Technical Manual - Rlsd

Technical Manual 

The difference is… 

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2 

…innovation, commitment, support. 

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For a service with a difference, choose 

Richard Lees Steel Decking, the UK 

specialist steel decking company 

with a 50 year history of innovation in 

structural flooring products. In fact, ours 

is a service which has delivered results 

worldwide, with major projects in over 

30 countries, including some of the 

world’s most prestigious buildings. 

A commitment to excellence drives 

every aspect of our work, from the 

innovation that has seen us introduce 

a number of ‘firsts’, to producing 

top quality products. Perhaps that’s 

why Holorib has become the generic 

term for steel decking in the UK and 

consistently outsells any other profile in 

the UK range. Based on our extensive 

experience of working at height, we’ve 

even created our own safety net division. 

On-going development partnerships 

to create new products and services 

have introduced the Resotec vibration 

damping system and synthetic fibre 

reinforced concrete to the UK market. 

This is a service that’s as complete as 

it is reassuring; with all the support 

you need from initial advice to 

complete installation. 

The difference is… 

Richard Lees Steel Decking 

3

Advantages of steel decking: 

Steel decking acts as permanent or ‘lost’ shuttering for suspended in situ concrete floor or roof slabs in new 

or refurbished buildings. On most projects, it will act as all, or part, of the tensile bottom reinforcement for the 

concrete slabs, hence the term ‘composite’. 

The use of steel decking is especially suitable for fast construction methods. Quick to install, simple, and an ideal 

complement to steel framed structures make steel decking ideal for both high and low rise buildings. Steel decking 

is also used to speed up and simplify the construction of brickwork, blockwork and concrete framed buildings. 

• Up to 4 hours’ fire resistance with exposed 

soffit can be designed. 

• Composite construction reduces steelwork frame weight. 

• Lower dead load reduces frame and foundation loading. 

• Stiffens steelwork supporting frame. 

• Cover for following trades. 

4 www.rlsd.com 

• Provides a safe working platform. 

• Easily cut and fitted to awkward shapes. 

• Minimal site storage requirements. 

• Needs no (or minimal) propping. 

• Ceilings and services can be easily 

suspended using standard fixings.

Contents Steel decking product range page 6 

Section properties and notes to tables page 7 

Resotec page 16 

Fibre reinforced concrete page 18 

Guidelines for concrete producers page 26 

Shaping the London skyline page 28 

Architectural impact across the UK page 34 

Guidance notes for design and fixing page 38 

Deckspan design software page 46 

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6 

Steel Decking Product Range 

the original: 

Holorib 

less concrete 

Ribdeck E60 

longer spans 

Ribdeck 80 

shallow slabs 

efficient designs 

Ribdeck AL 

Holorib 

• Re-entrant profile. 

• Available in the UK since 1972. 

• The UK’s most widely specified steel decking profile. 

• Simple to detail and install. 

• Virtually continuous plain soffit finish. 

• Excellent load carrying capacity on the finished slab. 

• Use Holorib for its great versatility and strength. 

Ribdeck E60 

• Trapezoidal profile. 

• Fast to install – 1.0m cover width. 

• Designed to minimise concrete volume. 

• Use Ribdeck E60 to reduce the 

overall cost of a floor slab. 

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Ribdeck 80 


• Longer unpropped spans. 

• Excellent bond to the concrete for 

greater load carrying capacity. 

• Use Ribdeck 80 to reduce the number 

of steel members in a frame. 

Ribdeck AL 


• Shallowest slabs to satisfy fire 

insulation requirements. 

• Use Ribdeck AL to minimise 

ribbed soffit slab depth. 

Registered trademarks: 

Ribdeck and Deskspan are registered trademarks throughout Europe. Holorib is a registered trademark in the UK, ROI, 

Gibraltar, Norway and Sweden and Superib (the same profile as Holorib) is registered in all other Western European countries.

Section properties and notes to tables 

Holorib Section Dimensions 

Standard soffit fixings 

Ribdeck E60 Section Dimensions 


Ribdeck 80 Section Dimensions 


Ribdeck AL Section Dimensions 


In pages 8-15 The performance of each product is given in terms of span/load and simplified fire design tables. 

Span/load tables 

1. Spans shown assume clear span +100mm to the centreline of supports. 

2. Designs are fully in accordance with BS 5950: Parts 4 & 6. 

3. The dead weight of the slab has been included in the development of the 

spans shown. However, consideration should be given to finishes, partitions, 

walls, etc. when reading from the table. 

4. Based upon concrete densities at wet stage: normal weight concrete 

2400 kg/m 3 , lightweight concrete 1900 kg/m 3 . 

5. A span to depth ratio limit of 35:1 for normal weight concrete and 30:1 for 

lightweight concrete is generally used. Where isolated single spans occur, 

these should be reduced to 30:1 and 25:1 respectively. 

6. Maximum deflection in the direction of span of the decking is limited to span/130 

after taking account of ponding. 

Simplified fire design tables 

1. Tables are applicable for any construction where the mesh may act in tension 

over a supporting beam or wall (negative bending). This includes end bay 

conditions i.e. the concrete slab is continuous over more than one span. 

2. Loads shown are unfactored working loads and should include all imposed 

live and dead loads, excluding only the self-weight of the slab. 

3. An ultimate load factor of 1.0 is assumed throughout. 

4. - indicates that the area of mesh is less than the minimum 

for crack control recommended in BS5950: Part 4 

Holorib Section Properties (per metre width) 

Gauge Self Weight Area Inertia YNA 

mm kg/m 2 kN/m 2 mm 2 cm 4 mm 

0.9 12.8 0.126 1,597 64.4 16.7 

1.0 14.3 0.140 1,780 72.0 16.7 

1.2 17.1 0.168 2,145 87.2 16.8 

Concrete volume figures in the span/load tables that follow are based on constant slab 

thickness. To take account of deflection of the decking profile it is recommended that 

the volume of concrete will equate to: Overall slab depth – 9mm for voids + span/250. 

An additional allowance may also be required to allow for deflections within the 

supporting structure (refer to building design engineer). 

Ribdeck E60 Section Properties (per metre width) 



0.9 9.3 0.091 1,140 80.4 37.1 

1.0 10.3 0.101 1,273 89.8 37.2 

1.2 12.3 0.121 1,538 108.7 37.2 






Ribdeck 80 Section Properties (per metre width) 



0.9 11.1 0.109 1,375 167.5 40.7 

1.0 12.3 0.121 1,533 186.7 40.7 

1.2 14.8 0.145 1,848 224.8 40.7 






Ribdeck AL Section Properties (per metre width) 



0.9 9.5 0.093 1,171 67.4 28.0 

1.0 10.5 0.103 1,301 75.2 28.0 

1.2 12.6 0.124 1,570 90.9 28.0 






7. Construction stage design includes an allowance of 1.5kN/m 2 for construction 

loading. 

8. Composite slabs are designed as simply supported irrespective of the deck 

support configuration. A minimum crack control and distribution mesh is 

required in accordance with clauses 6.7, 6.8 and 6.9 of BS5950: Part 4. 

Alternatively the use of synthetic fibre reinforcement may be deemed 

acceptable after reference to the relevant design tables and consultation with 

the structural design engineers. 

9. S350 decking is manufactured from material meeting the specification: 

BS EN 10326-S350GD+Z275-N-A-C. It has guaranteed minimum yield 

strength of 350 N/mm 2 . 

5. Mesh should satisfy the minimum elongation requirement 

given in BS4449: 1988. 

6. For conditions outside the scope of the simplified tables, including all isolated 

spans, consult SCI publication 56 (2nd edition) or RLSD’s Deckspan software. 

7. Tables are based on the thinnest gauge of decking available in each product 

range. Improved performance with thicker gauges may be checked for using 

RLSD’s Deckspan software. 

7

8 

Holorib - Normal weight concrete 

Single - Unpropped 

Multiple - Unpropped 

Multiple - Propped 

Normal weight concrete 

Span/load table Normal weight concrete 

Support 

Condition 

Slab Concrete 0.9 Gauge 1.0 Gauge 1.2 Gauge 

Depth Volume Imposed Load Imposed Load Imposed Load 

(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

100 0.092 3.05 3.05 3.05 2.95 3.25 3.25 3.25 2.99 3.44 3.44 3.44 3.07 

120 0.112 2.88 2.88 2.88 2.88 3.09 3.09 3.09 3.09 3.27 3.27 3.27 3.27 

130 0.122 2.80 2.80 2.80 2.80 3.02 3.02 3.02 3.02 3.20 3.20 3.20 3.20 

150 0.142 2.67 2.67 2.67 2.67 2.89 2.89 2.89 2.89 3.07 3.07 3.07 3.07 

175 0.167 2.52 2.52 2.52 2.52 2.75 2.75 2.75 2.75 2.93 2.93 2.93 2.93 

200 0.192 2.40 2.40 2.40 2.40 2.61 2.61 2.61 2.61 2.82 2.82 2.82 2.82 

250 0.242 2.20 2.20 2.20 2.20 2.40 2.40 2.40 2.40 2.63 2.63 2.63 2.63 

100 0.092 3.36 3.36 3.36 2.95 3.53 3.53 3.53 2.99 3.50 3.50 3.50 3.07 

120 0.112 3.19 3.19 3.19 3.19 3.35 3.35 3.35 3.35 3.66 3.66 3.66 3.59 

130 0.122 3.12 3.12 3.12 3.12 3.28 3.28 3.28 3.28 3.58 3.58 3.58 3.58 

150 0.142 2.99 2.99 2.99 2.99 3.14 3.14 3.14 3.14 3.44 3.44 3.44 3.44 

175 0.167 2.85 2.85 2.85 2.85 3.00 3.00 3.00 3.00 3.29 3.29 3.29 3.29 

200 0.192 2.74 2.74 2.74 2.74 2.89 2.89 2.89 2.89 3.16 3.16 3.16 3.16 

250 0.242 2.52 2.52 2.52 2.52 2.70 2.70 2.70 2.70 2.95 2.95 2.95 2.95 

100 0.092 3.50 3.50 3.39 2.85 3.50 3.50 3.50 2.99 3.50 3.50 3.50 3.07 

120 0.112 4.20 4.15 3.69 3.12 4.20 4.20 4.13 3.48 4.20 4.20 4.20 3.59 

130 0.122 4.55 4.30 3.84 3.25 4.55 4.55 4.29 3.63 4.55 4.55 4.55 3.85 

150 0.142 5.25 4.58 4.10 3.48 5.25 5.11 4.58 3.89 5.25 5.25 5.25 4.38 

175 0.167 5.66 4.87 4.39 3.75 5.96 5.43 4.90 4.19 6.13 6.13 5.90 5.02 

200 0.192 5.43 5.12 4.64 3.98 5.72 5.70 5.17 4.45 6.27 6.27 6.23 5.37 

250 0.242 5.07 5.07 5.05 4.38 5.34 5.34 5.34 4.89 5.85 5.85 5.85 5.85 

Simplified fire design table Normal weight concrete 

Fire Rating Slab Span (m) for given Imposed Load (kN/m2 (Hrs) Depth 

(mm) 5.0 

A142 

6.7 

) 

A193 

10.0 5.0 6.7 10.0 5.0 

A252 

6.7 10.0 

100 3.36 3.36 2.95 3.36 3.36 2.95 3.36 3.36 2.95 

120 3.19 3.19 3.19 3.19 3.19 3.19 3.19 3.19 3.19 

130 3.12 3.12 3.12 3.12 3.12 3.12 3.12 3.12 3.12 

1.0 150 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 

175 - - - 2.85 2.85 2.85 2.85 2.85 2.85 

200 - - - 2.74 2.74 2.74 2.74 2.74 2.74 

250 - - - - - - 2.52 2.52 2.52 

110 3.27 3.12 2.70 3.27 3.27 2.90 3.27 3.27 3.11 

120 3.19 3.19 2.81 3.19 3.19 3.03 3.19 3.19 3.19 

130 3.12 3.12 2.92 3.12 3.12 3.12 3.12 3.12 3.12 

1.5 150 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 2.99 

175 - - - 2.85 2.85 2.85 2.85 2.85 2.85 

200 - - - 2.74 2.74 2.74 2.74 2.74 2.74 

250 - - - - - - 2.52 2.52 2.52 

125 3.05 2.78 2.42 3.15 3.06 2.66 3.15 3.15 2.90 

130 3.11 2.83 2.47 3.12 3.12 2.71 3.12 3.12 2.96 

2.0 150 2.99 2.99 2.62 2.99 2.99 2.89 2.99 2.99 2.99 

175 - - - 2.85 2.85 2.85 2.85 2.85 2.85 

200 - - - 2.74 2.74 2.74 2.74 2.74 2.74 

250 - - - - - - 2.52 2.52 2.52 

Refer to page 7 for notes on the use of these tables 

the original: 

Holorib

Holorib - Lightweight concrete 




Lightweight concrete 

Span/load table Lightweight concrete 

Support 

Condition 



(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

100 0.092 3.00 3.00 3.00 2.77 3.00 3.00 3.00 2.81 3.00 3.00 3.00 2.88 

120 0.112 3.10 3.10 3.10 3.10 3.31 3.31 3.31 3.28 3.50 3.50 3.50 3.36 

130 0.122 3.03 3.03 3.03 3.03 3.24 3.24 3.24 3.24 3.43 3.43 3.43 3.43 

150 0.142 2.90 2.90 2.90 2.90 3.11 3.11 3.11 3.11 3.29 3.29 3.29 3.29 

175 0.167 2.75 2.75 2.75 2.75 2.97 2.97 2.97 2.97 3.15 3.15 3.15 3.15 

200 0.192 2.62 2.62 2.62 2.62 2.85 2.85 2.85 2.85 3.03 3.03 3.03 3.03 

250 0.242 2.41 2.41 2.41 2.41 2.63 2.63 2.63 2.63 2.83 2.83 2.83 2.83 

100 0.092 3.00 3.00 3.00 2.77 3.00 3.00 3.00 2.81 3.00 3.00 3.00 2.88 

120 0.112 3.42 3.42 3.42 3.23 3.60 3.60 3.60 3.28 3.60 3.60 3.60 3.36 

130 0.122 3.34 3.34 3.34 3.34 3.52 3.52 3.52 3.52 3.84 3.84 3.84 3.61 

150 0.142 3.21 3.21 3.21 3.21 3.38 3.38 3.38 3.38 3.69 3.69 3.69 3.69 

175 0.167 3.07 3.07 3.07 3.07 3.23 3.23 3.23 3.23 3.53 3.53 3.53 3.53 

200 0.192 2.95 2.95 2.95 2.95 3.10 3.10 3.10 3.10 3.40 3.40 3.40 3.40 

250 0.242 2.75 2.75 2.75 2.75 2.90 2.90 2.90 2.90 3.18 3.18 3.18 3.18 

100 0.092 3.00 3.00 3.00 2.77 3.00 3.00 3.00 2.81 3.00 3.00 3.00 2.88 

120 0.112 3.60 3.60 3.60 3.16 3.60 3.60 3.60 3.28 3.60 3.60 3.60 3.36 

130 0.122 3.90 3.90 3.90 3.30 3.90 3.90 3.90 3.52 3.90 3.90 3.90 3.61 

150 0.142 4.50 4.50 4.21 3.55 4.50 4.50 4.50 3.97 4.50 4.50 4.50 4.11 

175 0.167 5.25 5.06 4.52 3.83 5.25 5.25 5.05 4.28 5.25 5.25 5.25 4.72 

200 0.192 5.84 5.34 4.79 4.08 6.00 5.95 5.35 4.56 6.00 6.00 6.00 5.33 

250 0.242 5.46 5.46 5.25 4.51 5.75 5.75 5.75 5.04 6.30 6.30 6.30 6.08 

Simplified fire design table Lightweight concrete 


(mm) 5.0 

A142 

6.7 

) 

A193 

10.0 5.0 6.7 10.0 5.0 

A252 

6.7 10.0 

100 3.00 3.00 2.77 3.00 3.00 2.77 3.00 3.00 2.77 

120 3.42 3.42 3.23 3.42 3.42 3.23 3.42 3.42 3.23 

130 3.34 3.34 3.34 3.34 3.34 3.34 3.34 3.34 3.34 

1.0 150 3.21 3.21 3.21 3.21 3.21 3.21 3.21 3.21 3.21 

175 - - - 3.07 3.07 3.07 3.07 3.07 3.07 

200 - - - 2.95 2.95 2.95 2.95 2.95 2.95 

250 - - - - - - 2.75 2.75 2.75 

105 3.15 3.15 2.73 3.15 3.15 2.88 3.15 3.15 2.88 

120 3.42 3.40 2.92 3.42 3.42 3.16 3.42 3.42 3.23 

130 3.34 3.34 3.04 3.34 3.34 3.28 3.34 3.34 3.34 

1.5 150 3.21 3.21 3.18 3.21 3.21 3.21 3.21 3.21 3.21 

175 - - - 3.07 3.07 3.07 3.07 3.07 3.07 

200 - - - 2.95 2.95 2.95 2.95 2.95 2.95 

250 - - - - - - 2.75 2.75 2.75 

115 3.17 2.86 2.46 3.45 3.17 2.72 3.45 3.45 2.98 

120 3.23 2.92 2.51 3.42 3.23 2.78 3.42 3.42 3.05 

130 3.34 3.03 2.61 3.34 3.34 2.89 3.34 3.34 3.17 

2.0 150 3.21 3.17 2.75 3.21 3.21 3.04 3.21 3.21 3.21 

175 - - - 3.07 3.07 3.07 3.07 3.07 3.07 

200 - - - 2.95 2.95 2.95 2.95 2.95 2.95 

250 - - - - - - 2.75 2.75 2.75 


9

10 

Ribdeck E60 - Normal weight concrete 






Support 

Condition 

less concrete 

Ribdeck E60 



(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

130 0.094 2.74 2.74 2.74 2.59 3.10 3.10 3.10 2.76 3.44 3.44 3.44 3.06 

140 0.104 2.68 2.68 2.68 2.68 3.03 3.03 3.03 2.91 3.36 3.36 3.36 3.25 

150 0.114 2.62 2.62 2.62 2.62 2.96 2.96 2.96 2.96 3.29 3.29 3.29 3.29 

160 0.124 2.57 2.57 2.57 2.57 2.90 2.90 2.90 2.90 3.23 3.23 3.23 3.23 

175 0.139 2.49 2.49 2.49 2.49 2.82 2.82 2.82 2.82 3.14 3.14 3.14 3.14 

200 0.164 2.39 2.39 2.39 2.39 2.71 2.71 2.71 2.71 3.01 3.01 3.01 3.01 

250 0.214 2.22 2.22 2.22 2.22 2.52 2.52 2.52 2.52 2.81 2.81 2.81 2.81 

130 0.094 3.31 3.31 3.22 2.59 3.67 3.67 3.47 2.76 4.00 4.00 3.93 3.06 

140 0.104 3.22 3.22 3.22 2.72 3.58 3.58 3.58 2.91 3.90 3.90 3.90 3.25 

150 0.114 3.14 3.14 3.14 2.87 3.49 3.49 3.49 3.07 3.81 3.81 3.81 3.45 

160 0.124 3.07 3.07 3.07 3.00 3.41 3.41 3.41 3.23 3.72 3.72 3.72 3.64 

175 0.139 2.96 2.96 2.96 2.96 3.30 3.30 3.30 3.30 3.61 3.61 3.61 3.61 

200 0.164 2.79 2.79 2.79 2.79 3.14 3.14 3.14 3.14 3.45 3.45 3.45 3.45 

250 0.214 2.53 2.53 2.53 2.53 2.87 2.87 2.87 2.87 3.19 3.19 3.19 3.19 

130 0.094 4.55 3.35 2.93 2.43 4.55 3.61 3.14 2.58 4.55 4.10 3.53 2.85 

140 0.104 4.90 3.49 3.07 2.54 4.90 3.78 3.30 2.71 4.90 4.32 3.72 3.00 

150 0.114 5.25 3.64 3.20 2.66 5.25 3.95 3.45 2.84 5.25 4.52 3.90 3.16 

160 0.124 5.60 3.78 3.32 2.77 5.60 4.10 3.59 2.96 5.60 4.72 4.08 3.31 

175 0.139 5.88 3.96 3.50 2.92 6.13 4.32 3.79 3.13 6.13 5.00 4.33 3.52 

200 0.164 5.59 4.24 3.76 3.15 6.23 4.64 4.09 3.40 6.50 5.40 4.71 3.84 

250 0.214 5.11 4.70 4.21 3.56 5.71 5.17 4.60 3.86 6.16 6.07 5.35 4.41 



(mm) 5.0 

A142 

6.7 

) 

A193 

10.0 5.0 6.7 10.0 5.0 

A252 

6.7 10.0 

130 3.31 3.22 2.59 3.31 3.22 2.59 3.31 3.22 2.59 

140 3.22 3.22 2.72 3.22 3.22 2.72 3.22 3.22 2.72 

150 3.14 3.14 2.87 3.14 3.14 2.87 3.14 3.14 2.87 

1.0 160 3.07 3.07 3.00 3.07 3.07 3.00 3.07 3.07 3.00 

175 2.96 2.96 2.96 2.96 2.96 2.96 2.96 2.96 2.96 

200 - - - 2.79 2.79 2.79 2.79 2.79 2.79 

250 - - - - - - 2.53 2.53 2.53 

140 3.22 3.02 2.61 3.22 3.22 2.72 3.22 3.22 2.72 

150 3.14 3.14 2.74 3.14 3.14 2.87 3.14 3.14 2.87 

1.5 160 3.07 3.07 2.81 3.07 3.07 3.00 3.07 3.07 3.00 

175 2.96 2.96 2.88 2.96 2.96 2.96 2.96 2.96 2.96 

200 - - - 2.79 2.79 2.79 2.79 2.79 2.79 

250 - - - - - - 2.53 2.53 2.53 

150 3.08 2.81 2.44 3.14 3.13 2.72 3.14 3.14 2.87 

160 3.07 2.92 2.55 3.07 3.07 2.84 3.07 3.07 3.00 

2.0 175 2.96 2.96 2.61 2.96 2.96 2.91 2.96 2.96 2.96 

200 - - - 2.79 2.79 2.79 2.79 2.79 2.79 

250 - - - - - - 2.53 2.53 2.53 

Refer to page 7 for notes on the use of these tables

Ribdeck E60 - Lightweight concrete 


Multiple - Propped Multiple - Unpropped Single - Unpropped 

Support 

Condition 



(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

120 0.094 2.98 2.98 2.98 2.44 3.36 3.36 3.26 2.60 3.60 3.60 3.59 2.86 

130 0.104 2.91 2.91 2.91 2.59 3.28 3.28 3.28 2.76 3.64 3.64 3.64 3.06 

140 0.114 2.84 2.84 2.84 2.72 3.21 3.21 3.21 2.91 3.57 3.57 3.57 3.25 

150 0.124 2.78 2.78 2.78 2.78 3.15 3.15 3.15 3.07 3.50 3.50 3.50 3.45 

175 0.139 2.66 2.66 2.66 2.66 3.01 3.01 3.01 3.01 3.34 3.34 3.34 3.34 

200 0.164 2.55 2.55 2.55 2.55 2.89 2.89 2.89 2.89 3.21 3.21 3.21 3.21 

250 0.214 2.38 2.38 2.38 2.38 2.69 2.69 2.69 2.69 3.00 3.00 3.00 3.00 

120 0.094 3.61 3.57 3.03 2.44 3.60 3.60 3.26 2.60 3.60 3.60 3.59 2.86 

130 0.104 3.52 3.52 3.22 2.59 3.90 3.90 3.47 2.76 3.90 3.90 3.87 3.06 

140 0.114 3.44 3.44 3.40 2.72 3.82 3.82 3.68 2.91 4.18 4.18 4.14 3.25 

150 0.124 3.36 3.36 3.36 2.87 3.73 3.73 3.73 3.07 4.08 4.08 4.08 3.45 

175 0.139 3.19 3.19 3.19 3.19 3.55 3.55 3.55 3.45 3.88 3.88 3.88 3.88 

200 0.164 3.04 3.04 3.04 3.04 3.39 3.39 3.39 3.39 3.70 3.70 3.70 3.70 

250 0.214 2.77 2.77 2.77 2.77 3.12 3.12 3.12 3.12 3.43 3.43 3.43 3.43 

120 0.094 3.60 3.26 2.84 2.33 3.60 3.52 3.04 2.48 3.60 3.60 3.40 2.73 

130 0.104 3.90 3.43 2.99 2.46 3.90 3.71 3.21 2.62 3.90 3.90 3.61 2.89 

140 0.114 4.20 3.59 3.13 2.58 4.20 3.90 3.37 2.75 4.20 4.20 3.81 3.05 

150 0.124 4.50 3.75 3.27 2.70 4.50 4.08 3.53 2.89 4.50 4.50 4.01 3.22 

175 0.139 5.25 4.11 3.60 2.98 5.25 4.49 3.90 3.20 5.25 5.21 4.47 3.60 

200 0.164 6.03 4.42 3.89 3.23 6.00 4.85 4.23 3.48 6.00 5.67 4.89 3.94 

250 0.214 5.55 4.94 4.38 3.66 6.19 5.46 4.80 3.98 6.50 6.45 5.61 4.56 

Fire Rating 

(mm) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

120 3.57 3.03 2.44 3.57 3.03 2.44 3.57 3.03 2.44 

130 3.52 3.22 2.59 3.52 3.22 2.59 3.52 3.22 2.59 

140 3.44 3.40 2.72 3.44 3.40 2.72 3.44 3.40 2.72 

1.0 150 3.36 3.36 2.87 3.36 3.36 2.87 3.36 3.36 2.87 

175 3.19 3.19 3.19 3.19 3.19 3.19 3.19 3.19 3.19 

200 - - - 3.04 3.04 3.04 3.04 3.04 3.04 

250 - - - - - - 2.77 2.77 2.77 

130 3.42 3.08 2.59 3.52 3.22 2.59 3.52 3.22 2.59 

140 3.44 3.25 2.72 3.44 3.40 2.72 3.44 3.40 2.72 

1.5 150 3.36 3.31 2.85 3.36 3.36 2.87 3.36 3.36 2.87 

175 3.19 3.19 2.98 3.19 3.19 3.19 3.19 3.19 3.19 

200 - - - 3.04 3.04 3.04 3.04 3.04 3.04 

250 - - - - - - 2.77 2.77 2.77 

140 3.26 2.95 2.53 3.44 3.29 2.72 3.44 3.40 2.72 

150 3.36 3.05 2.63 3.36 3.36 2.87 3.36 3.36 2.87 

2.0 175 3.19 3.16 2.74 3.19 3.19 3.07 3.19 3.19 3.19 

200 - - - 3.04 3.04 3.04 3.04 3.04 3.04 

250 - - - - - - 2.77 2.77 2.77 

Slab Span (m) for given Imposed Load (kN/m2 (Hrs) Depth A142 

) 

A193 A252 

Lightweight concrete Simplified fire design table Lightweight concrete 


11

12 

Ribdeck 80 - Normal weight concrete 






Support 

Condition 



(mm) 5.0 

A142 

6.7 10.0 

) 

A193 A252 

5.0 6.7 10.0 5.0 6.7 10.0 5.0 

A393 

6.7 10.0 

140 3.65 3.31 2.86 3.91 3.55 3.06 4.01 3.79 3.27 4.01 4.01 3.51 

150 3.84 3.49 3.02 3.91 3.75 3.25 3.91 3.91 3.48 3.91 3.91 3.73 

160 3.82 3.64 3.16 3.82 3.82 3.41 3.82 3.82 3.65 3.82 3.82 3.82 

1.0 170 3.73 3.71 3.23 3.73 3.73 3.49 3.73 3.73 3.73 3.73 3.73 3.73 

175 3.69 3.69 3.26 3.69 3.69 3.52 3.69 3.69 3.69 3.69 3.69 3.69 

200 - - - 3.50 3.50 3.50 3.50 3.50 3.50 3.50 3.50 3.50 

250 - - - - - - 3.20 3.20 3.20 3.20 3.20 3.20 

150 3.31 3.01 2.61 3.60 3.27 2.83 3.89 3.54 3.06 3.91 3.91 3.51 

160 3.47 3.17 2.75 3.79 3.45 3.00 3.82 3.74 3.25 3.82 3.82 3.74 

1.5 170 3.61 3.30 2.87 3.73 3.60 3.14 3.73 3.73 3.41 3.73 3.73 3.73 

175 3.65 3.34 2.91 3.69 3.65 3.18 3.69 3.69 3.46 3.69 3.69 3.69 

200 - - - 3.50 3.50 3.31 3.50 3.50 3.50 3.50 3.50 3.50 

250 - - - - - - 3.20 3.20 3.20 3.20 3.20 3.20 

160 3.04 2.77 2.42 3.37 3.07 2.67 3.70 3.37 2.93 3.82 3.82 3.42 

170 3.18 2.91 2.54 3.53 3.23 2.81 3.73 3.55 3.09 3.73 3.73 3.62 

2.0 175 3.24 2.97 2.59 3.60 3.30 2.88 3.69 3.62 3.16 3.69 3.69 3.69 

200 - - - 3.50 3.43 3.02 3.50 3.50 3.32 3.50 3.50 3.50 

250 - - - - - - 3.20 3.20 3.20 3.20 3.20 3.20 

longer spans 

Ribdeck 80 

(mm) (m3 /m2 Slab Concrete 0.9 Gauge 1.0 Gauge 1.2 Gauge 


) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

140 0.098 3.73 3.73 3.73 3.51 4.11 4.11 4.11 3.56 4.28 4.28 4.28 3.67 

150 0.108 3.63 3.63 3.63 3.63 4.01 4.01 4.01 3.79 4.20 4.20 4.20 3.90 

160 0.118 3.55 3.55 3.55 3.55 3.92 3.92 3.92 3.92 4.12 4.12 4.12 4.12 

170 0.128 3.47 3.47 3.47 3.47 3.83 3.83 3.83 3.83 4.05 4.05 4.05 4.05 

175 0.133 3.43 3.43 3.43 3.43 3.79 3.79 3.79 3.79 4.02 4.02 4.02 4.02 

200 0.158 3.26 3.26 3.26 3.26 3.61 3.61 3.61 3.61 3.86 3.86 3.86 3.86 

250 0.208 2.97 2.97 2.97 2.97 3.30 3.30 3.30 3.30 3.57 3.57 3.57 3.57 

140 0.098 4.01 4.01 4.01 3.51 4.47 4.47 4.47 3.56 4.90 4.90 4.68 3.67 

150 0.108 3.91 3.91 3.91 3.73 4.36 4.36 4.36 3.79 5.09 5.09 4.99 3.90 

160 0.118 3.82 3.82 3.82 3.82 4.26 4.26 4.26 4.03 4.98 4.98 4.98 4.14 

170 0.128 3.73 3.73 3.73 3.73 4.17 4.17 4.17 4.17 4.87 4.87 4.87 4.38 

175 0.133 3.69 3.69 3.69 3.69 4.12 4.12 4.12 4.12 4.82 4.82 4.82 4.50 

200 0.158 3.50 3.50 3.50 3.50 3.92 3.92 3.92 3.92 4.60 4.60 4.60 4.60 

250 0.208 3.20 3.20 3.20 3.20 3.58 3.58 3.58 3.58 4.23 4.23 4.23 4.23 

140 0.098 4.90 4.74 4.33 3.51 4.90 4.81 4.39 3.56 4.90 4.90 4.51 3.67 

150 0.108 5.25 5.04 4.61 3.73 5.25 5.11 4.67 3.79 5.25 5.24 4.79 3.90 

160 0.118 5.60 5.34 4.88 3.97 5.60 5.41 4.95 4.03 5.60 5.55 5.08 4.14 

170 0.128 5.95 5.64 5.16 4.20 5.95 5.72 5.23 4.26 5.95 5.86 5.36 4.38 

175 0.133 6.13 5.79 5.26 4.31 6.13 5.87 5.37 4.38 6.13 6.02 5.50 4.50 

200 0.158 6.50 6.17 5.64 4.90 6.50 6.46 5.91 4.97 6.50 6.50 6.22 5.10 

250 0.208 6.37 6.37 6.22 5.48 6.50 6.50 6.50 5.75 6.50 6.50 6.50 6.15 


Ribdeck 80 - Lightweight concrete 






Support 

Condition 



(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

130 0.098 3.90 3.90 3.89 3.10 3.90 3.90 3.90 3.16 3.90 3.90 3.90 3.26 

140 0.108 3.97 3.97 3.97 3.30 4.20 4.20 4.20 3.36 4.20 4.20 4.20 3.46 

150 0.118 3.88 3.88 3.88 3.51 4.28 4.28 4.28 3.57 4.44 4.44 4.44 3.67 

160 0.128 3.80 3.80 3.80 3.73 4.19 4.19 4.19 3.79 4.36 4.36 4.36 3.89 

175 0.133 3.68 3.68 3.68 3.68 4.07 4.07 4.07 4.07 4.25 4.25 4.25 4.23 

200 0.158 3.51 3.51 3.51 3.51 3.88 3.88 3.88 3.88 4.10 4.10 4.10 4.10 

250 0.208 3.23 3.23 3.23 3.23 3.58 3.58 3.58 3.58 3.85 3.85 3.85 3.85 

130 0.098 3.90 3.90 3.89 3.10 3.90 3.90 3.90 3.16 3.90 3.90 3.90 3.26 

140 0.108 4.20 4.20 4.15 3.30 4.20 4.20 4.20 3.36 4.20 4.20 4.20 3.46 

150 0.118 4.18 4.18 4.18 3.51 4.50 4.50 4.49 3.57 4.50 4.50 4.50 3.67 

160 0.128 4.09 4.09 4.09 3.73 4.56 4.56 4.56 3.79 4.80 4.80 4.80 3.89 

175 0.133 3.96 3.96 3.96 3.96 4.43 4.43 4.43 4.11 5.18 5.18 5.18 4.23 

200 0.158 3.77 3.77 3.77 3.77 4.22 4.22 4.22 4.22 4.95 4.95 4.95 4.79 

250 0.208 3.47 3.47 3.47 3.47 3.89 3.89 3.89 3.89 4.58 4.58 4.58 4.58 

130 0.098 3.90 3.90 3.80 3.10 3.90 3.90 3.86 3.16 3.90 3.90 3.90 3.26 

140 0.108 4.20 4.20 4.04 3.30 4.20 4.20 4.11 3.36 4.20 4.20 4.20 3.46 

150 0.118 4.50 4.50 4.30 3.51 4.50 4.50 4.37 3.57 4.50 4.50 4.49 3.67 

160 0.128 4.80 4.80 4.56 3.73 4.80 4.80 4.63 3.79 4.80 4.80 4.75 3.89 

175 0.133 5.25 5.25 4.95 4.05 5.25 5.25 5.02 4.11 5.25 5.25 5.15 4.23 

200 0.158 6.00 6.00 5.59 4.59 6.00 6.00 5.67 4.66 6.00 6.00 5.82 4.79 

250 0.208 6.50 6.50 6.50 5.67 6.50 6.50 6.50 5.76 6.50 6.50 6.50 5.91 



(mm) 5.0 

A142 

6.7 10.0 

) 

A193 A252 

5.0 6.7 10.0 5.0 6.7 10.0 5.0 

A393 

6.7 10.0 

130 3.62 3.25 2.78 3.87 3.48 2.98 3.90 3.72 3.10 3.90 3.89 3.10 

140 3.85 3.47 2.98 4.15 3.73 3.20 4.20 4.00 3.30 4.20 4.15 3.30 

150 4.04 3.65 3.14 4.18 3.94 3.38 4.18 4.18 3.51 4.18 4.18 3.51 

1.0 160 4.09 3.78 3.26 4.09 4.09 3.52 4.09 4.09 3.73 4.09 4.09 3.73 

175 3.96 3.89 3.36 3.96 3.96 3.63 3.96 3.96 3.90 3.96 3.96 3.96 

200 - - - 3.77 3.77 3.77 3.77 3.77 3.77 3.77 3.77 3.77 

250 - - - - - - 3.47 3.47 3.47 3.47 3.47 3.47 

140 3.37 3.04 2.61 3.68 3.31 2.84 3.99 3.59 3.08 4.20 4.13 3.30 

150 3.59 3.24 2.79 3.93 3.55 3.05 4.18 3.85 3.31 4.18 4.18 3.51 

1.5 160 3.76 3.40 2.93 4.09 3.73 3.21 4.09 4.06 3.50 4.09 4.09 3.73 

175 3.84 3.49 3.02 3.96 3.82 3.31 3.96 3.96 3.60 3.96 3.96 3.96 

200 - - - 3.77 3.77 3.44 3.77 3.77 3.74 3.77 3.77 3.77 

250 - - - - - - 3.47 3.47 3.47 3.47 3.47 3.47 

150 3.18 2.87 2.47 3.53 3.19 2.75 3.89 3.51 3.02 4.18 4.12 3.51 

160 3.37 3.05 2.63 3.75 3.39 2.93 4.09 3.74 3.22 4.09 4.09 3.73 

2.0 175 3.49 3.17 2.74 3.89 3.54 3.06 3.96 3.90 3.37 3.96 3.96 3.96 

200 - - - 3.77 3.64 3.17 3.77 3.77 3.49 3.77 3.77 3.77 

250 - - - - - - 3.47 3.47 3.47 3.47 3.47 3.47 


13

14 

Ribdeck AL - Normal weight concrete 






Support 

Condition 

shallow slabs 


Ribdeck AL 



(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

120 0.095 2.96 2.96 2.96 2.95 3.06 3.06 3.06 3.06 3.23 3.23 3.23 3.20 

130 0.105 2.88 2.88 2.88 2.88 2.98 2.98 2.98 2.98 3.15 3.15 3.15 3.15 

140 0.115 2.81 2.81 2.81 2.81 2.90 2.90 2.90 2.90 3.07 3.07 3.07 3.07 

150 0.125 2.75 2.75 2.75 2.75 2.84 2.84 2.84 2.84 3.00 3.00 3.00 3.00 

175 0.150 2.61 2.61 2.61 2.61 2.70 2.70 2.70 2.70 2.85 2.85 2.85 2.85 

200 0.175 2.49 2.49 2.49 2.49 2.58 2.58 2.58 2.58 2.73 2.73 2.73 2.73 

250 0.225 2.31 2.31 2.31 2.31 2.39 2.39 2.39 2.39 2.53 2.53 2.53 2.53 

120 0.095 3.27 3.27 3.27 2.95 3.53 3.53 3.53 3.08 3.81 3.81 3.81 3.20 

130 0.105 3.19 3.19 3.19 3.14 3.44 3.44 3.44 3.27 3.71 3.71 3.71 3.44 

140 0.115 3.12 3.12 3.12 3.12 3.36 3.36 3.36 3.36 3.62 3.62 3.62 3.62 

150 0.125 3.05 3.05 3.05 3.05 3.28 3.28 3.28 3.28 3.54 3.54 3.54 3.54 

175 0.150 2.88 2.88 2.88 2.88 3.12 3.12 3.12 3.12 3.37 3.37 3.37 3.37 

200 0.175 2.73 2.73 2.73 2.73 2.99 2.99 2.99 2.99 3.23 3.23 3.23 3.23 

250 0.225 2.48 2.48 2.48 2.48 2.76 2.76 2.76 2.76 3.00 3.00 3.00 3.00 

120 0.095 4.20 3.94 3.40 2.75 4.20 4.10 3.53 2.87 4.20 4.20 3.80 3.10 

130 0.105 4.55 4.14 3.57 2.90 4.55 4.30 3.72 3.02 4.55 4.55 3.99 3.26 

140 0.115 4.90 4.34 3.75 3.05 4.90 4.50 3.90 3.17 4.90 4.82 4.19 3.42 

150 0.125 5.25 4.52 3.92 3.19 5.25 4.69 4.07 3.32 5.25 5.02 4.37 3.58 

175 0.150 5.73 4.94 4.30 3.52 6.13 5.12 4.47 3.66 6.13 5.47 4.79 3.93 

200 0.175 5.47 5.30 4.65 3.82 5.92 5.49 4.82 3.97 6.40 5.86 5.16 4.26 

250 0.225 5.03 5.03 5.03 4.34 5.49 5.49 5.41 4.51 5.95 5.95 5.78 4.83 



(mm) 5.0 

A142 

6.7 

) 

A193 

10.0 5.0 6.7 10.0 5.0 

A252 

6.7 10.0 

120 3.27 3.23 2.79 3.27 3.27 2.95 3.27 3.27 2.95 

130 3.19 3.19 2.93 3.19 3.19 3.14 3.19 3.19 3.14 

140 3.12 3.12 3.01 3.12 3.12 3.12 3.12 3.12 3.12 

1.0 150 3.05 3.05 3.05 3.05 3.05 3.05 3.05 3.05 3.05 

175 - - - 2.88 2.88 2.88 2.88 2.88 2.88 

200 - - - 2.73 2.73 2.73 2.73 2.73 2.73 

250 - - - - - - 2.48 2.48 2.48 

130 3.19 2.96 2.57 3.19 3.19 2.80 3.19 3.19 3.04 

140 3.12 3.10 2.69 3.12 3.12 2.94 3.12 3.12 3.12 

1.5 150 3.05 3.05 2.75 3.05 3.05 3.02 3.05 3.05 3.05 

175 - - - 2.88 2.88 2.88 2.88 2.88 2.88 

200 - - - 2.73 2.73 2.73 2.73 2.73 2.73 

250 - - - - - - 2.48 2.48 2.48 

140 3.01 2.74 2.38 3.12 3.05 2.65 3.12 3.12 2.90 

150 3.05 2.85 2.49 3.05 3.05 2.76 3.05 3.05 3.04 

2.0 175 - - - 2.88 2.88 2.88 2.88 2.88 2.88 

200 - - - 2.73 2.73 2.73 2.73 2.73 2.73 

250 - - - - - - 2.48 2.48 2.48 


Ribdeck AL - Lightweight concrete 




Lightweight concrete 


Support 

Condition 



(mm) (m3 /m2 ) FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 FW 5.0 6.7 10.0 

110 0.095 3.27 3.27 3.27 2.67 3.30 3.30 3.30 2.72 3.30 3.30 3.30 2.80 

120 0.105 3.18 3.18 3.18 2.88 3.28 3.28 3.28 2.93 3.46 3.46 3.46 3.01 

130 0.115 3.09 3.09 3.09 3.09 3.19 3.19 3.19 3.15 3.37 3.37 3.37 3.23 

150 0.125 2.95 2.95 2.95 2.95 3.05 3.05 3.05 3.05 3.22 3.22 3.22 3.22 

175 0.150 2.80 2.80 2.80 2.80 2.90 2.90 2.90 2.90 3.06 3.06 3.06 3.06 

200 0.175 2.68 2.68 2.68 2.68 2.77 2.77 2.77 2.77 2.93 2.93 2.93 2.93 

250 0.225 2.49 2.49 2.49 2.49 2.58 2.58 2.58 2.58 2.73 2.73 2.73 2.73 

110 0.095 3.30 3.30 3.30 2.67 3.30 3.30 3.30 2.72 3.30 3.30 3.30 2.80 

120 0.105 3.49 3.49 3.49 2.88 3.60 3.60 3.60 2.93 3.60 3.60 3.60 3.01 

130 0.115 3.41 3.41 3.41 3.10 3.69 3.69 3.69 3.15 3.90 3.90 3.90 3.23 

150 0.125 3.27 3.27 3.27 3.27 3.53 3.53 3.53 3.53 3.81 3.81 3.81 3.70 

175 0.150 3.11 3.11 3.11 3.11 3.35 3.35 3.35 3.35 3.62 3.62 3.62 3.62 

200 0.175 2.97 2.97 2.97 2.97 3.21 3.21 3.21 3.21 3.47 3.47 3.47 3.47 

250 0.225 2.72 2.72 2.72 2.72 2.99 2.99 2.99 2.99 3.23 3.23 3.23 3.23 

110 0.095 3.30 3.30 3.27 2.63 3.30 3.30 3.30 2.72 3.30 3.30 3.30 2.80 

120 0.105 3.60 3.60 3.47 2.79 3.60 3.60 3.60 2.91 3.60 3.60 3.60 3.01 

130 0.115 3.90 3.90 3.66 2.95 3.90 3.90 3.81 3.07 3.90 3.90 3.90 3.23 

150 0.125 4.50 4.50 4.04 3.25 4.50 4.50 4.19 3.39 4.50 4.50 4.50 3.65 

175 0.150 5.25 5.17 4.46 3.60 5.25 5.25 4.62 3.75 5.25 5.25 4.95 4.03 

200 0.175 5.90 5.58 4.83 3.92 6.00 5.78 5.01 4.08 6.00 6.00 5.36 4.38 

250 0.225 5.46 5.46 5.46 4.49 5.92 5.92 5.69 4.66 6.41 6.41 6.06 4.99 



(mm) 5.0 

A142 

6.7 

) 

A193 

10.0 5.0 6.7 10.0 5.0 

A252 

6.7 10.0 

110 3.30 3.18 2.67 3.30 3.30 2.67 3.30 3.30 2.67 

120 3.49 3.37 2.88 3.49 3.49 2.88 3.49 3.49 2.88 

130 3.41 3.41 3.01 3.41 3.41 3.10 3.41 3.41 3.10 

1.0 150 3.27 3.27 3.15 3.27 3.27 3.27 3.27 3.27 3.27 

175 - - - 3.11 3.11 3.11 3.11 3.11 3.11 

200 - - - 2.97 2.97 2.97 2.97 2.97 2.97 

250 - - - - - - 2.72 2.72 2.72 

120 3.35 3.01 2.58 3.49 3.31 2.83 3.49 3.49 2.88 

130 3.41 3.17 2.73 3.41 3.41 3.00 3.41 3.41 3.10 

1.5 150 3.27 3.27 2.85 3.27 3.27 3.13 3.27 3.27 3.27 

175 - - - 3.11 3.11 3.11 3.11 3.11 3.11 

200 - - - 2.97 2.97 2.97 2.97 2.97 2.97 

250 - - - - - - 2.72 2.72 2.72 

130 3.18 2.87 2.47 3.41 3.20 2.75 3.41 3.41 3.03 

150 3.27 3.02 2.61 3.27 3.27 2.91 3.27 3.27 3.22 

2.0 175 - - - 3.11 3.11 3.03 3.11 3.11 3.11 

200 - - - 2.97 2.97 2.97 2.97 2.97 2.97 

250 - - - - - - 2.72 2.72 2.72 


15

16 

Resotec is an innovative way to design footfall vibration damping into a building. In the past a great 

emphasis has been put on countering vibrations through the provision of mass in the structure but with 

Resotec the building can remain lightweight whilst still benefiting from a low design response factor. 

www.rlsd.com

What is it? 

Resotec is a thin constrained layer damping membrane that 

sits between the soffit of the steel decking and parts of the top 

flange of the steel beams. In these zones there is no mechanical 

connection between the floor and the supporting structure, 

allowing the two to move independently under the influence of 

vibration induced excitation. 

Where does it go? 

For maximum effectiveness the Resotec strips are installed on 

the top flange of a steel beam, extending from each end for 

approximately one quarter of the length towards the middle 

of the span. Steel decking can then be laid over the top of the 

Resotec but it should not be secured down to the beams in 

any way. Instead fixity is achieved by side lapping and stitching 

together the sheets to form one continuous membrane. 

Composite beams 

In a traditional secondary beam design the shear studs are 

evenly spaced along the length of the beam. With a Resotec 

layer installed there can be no shear studs in the outer quarter 

portion of the beam so a new approach is needed. The result is 

a 50% partially composite beam design which is illustrated in 

the Bending Moment diagram. Shear studs are installed in the 

middle section of the beam and the design allows for partial 

interaction between the beam and the slab to be developed 

in this zone only. The bending and shear resistance of the 

structure in the outer quarter regions of the beam is that of the 

steel section alone with no composite interaction with the slab. 

Design assistance 

Engineers are encouraged to consider the use of Resotec 

when designing large column free floor areas with lightweight 

long span beams. Because of the effects Resotec has on the 

placement of shear studs and the design of the supporting 

structure it is seldom possible to incorporate Resotec as a 

last minute solution to a footfall vibration issue. Engineers are 

therefore encouraged to consider Resotec in the early stages 

of a building design. Assistance for doing this can be obtained 

through the use of COMPOS, part of the OASYS suite of 

structural design programmes, or through contacting Richard 

Lees Steel Decking. 

Moment (Nm) 

X 105 

16 

14 

12 

10 

8 

6 

2 

0 

0 

Strength 

required 

50% partially composite beam: BM capacity and demand 

Beam 

strength 

Strength provided 

in 100% 

composite design 

Effect with Resotec 

Partially composite 

5 10 15 

Length (m) 

17

18 

www.rlsd.com 

Fibre Reinforced 

Concrete 

Traditional composite floor slab design 

makes use of the decking profile to act 

as tensile reinforcement in the bottom of 

the slab. It also includes a layer of welded 

wire fabric in the top of the slab to control 

cracks, distribute loads around minor 

openings, resist horizontal shear forces, 

and to provide continuity over supports in 

the fire limit state. In many design cases 

synthetic macro fibre reinforcement can be 

used to replace the fabric layer and provide 

added benefits associated with simplicity 

and speed of construction. 

STRUX ® 90/40 fibre 

reinforcement 

STRUX ® 90/40 synthetic structural fibres are 

marketed by Grace Construction Products 

Limited and have been used extensively in 

ground slabs for a number of years. 

The fibres are 40 mm long with an aspect 

ratio of 90, giving high strength with a high 

modulus. They have been designed to 

provide tight crack control whilst exhibiting 

excellent dispersion and pumpability 

characteristics. STRUX ® 90/40 synthetic 

structural fibres offer a quick, easy and safe 

option for providing secondary reinforcement 

to a composite floor slab. 

Application 

In collaboration with Grace Construction 

Products Limited, Richard Lees Steel 

Decking have researched and developed 

a system whereby much of the steel 

reinforcement in a composite floor slab can 

be replaced by fibres in the concrete mix. 

The development of this system required full 

scale testing of structural floor slabs and the 

results are therefore only applicable to the 

unique combinations of decking profile, fibre 

and fibre dosage tested. The test programme 

was developed in conjunction with the Steel 

Construction Institute (SCI) and the results 

processed by them to produce the design 

guidance given here. In the pages that 

follow design information is given for the 

use of Holorib, Ribdeck E60, Ribdeck 80 

and Ribdeck AL with STRUX ® 90/40 

synthetic structural fibres at a dosage of 

5.3 kg/m 3 of concrete. These products 

cannot be substituted with other types of 

decking or fibres based on the information 

published here.

Principal Benefits 

Extensive testing, specified and verified by the Steel Construction Institute, has shown that STRUX ® 90/40 can be an ideal replacement 

for steel fabric reinforcement in steel composite decks designed and supplied by Richard Lees Steel Decking Ltd. This testing has 

shown that, not only can the STRUX ® 90/40 reinforcement meet the physical requirements for longitudinal shear and composite 

interaction in the floor plate, but also that with Holorib, a fire rating of up to two hours can be achieved. 

Advantages of STRUX ® 90/40 over steel 

fabric reinforcement 

STRUX ® 90/40 reinforcement is premixed into the concrete so 

that when concrete is delivered to site it is immediately ready 

to be pumped and placed. 

Project time & cost 

• No fabric to lift to level. 

• No fabric storage space required. 

• No fabric to fix, eliminating an entire step from the process. 

• Productivity improvements. 

• Reduction in clashes with the requirements of other 

contractors. 

Safety 

• Risk reduction. 

• Removal of all hazards associated with the 

installation of fabric. 

• Removal of a trip hazard from the floor area prior to and 

during concreting. 

Flexibility & ease of application 

• Improved logistics on site. 

• Easier to maintain a clean and clear area for concrete 

placement. 

• Reduction in pre-pour inspection checks of reinforcement. 

• Concrete arrives on site with STRUX ® 90/40 already added. 

Superior crack control 

• STRUX ® 90/40 fibres are evenly distributed through the 

concrete and always in the right place. 

• Crack propagation is arrested early. 

Advantages of STRUX ® 90/40 

over steel fibres 

The high strength to weight ratio of STRUX ® 90/40 and high 

fineness compared to steel fibres leads to very different 

dosage rates of the two materials. In composite floor slabs 

STRUX ® 90/40 is added at a dosage rate of 5.3kg/m 3 . 

A similar application using steel fibres would require a 

dosage of 30kg/m 3 . 

Clear advantages of STRUX ® 90/40 include: 

• Ease of addition 

No specialist equipment is needed to add STRUX ® 90/40 to 

the mixing plant. A simple platform or suitable mobile steps 

will give safe access for adding the material. 

• Safe & easy to handle 

Individual bags of STRUX ® 90/40 are light (2.3kg), safe and 

easy to handle. 

Span/load/fire tables 

1. Spans shown assume clear span +100mm to the centreline of supports. 

2. Designs are fully in accordance with BS 5950: Parts 4 & 6. 

3. The dead weight of the slab has been included in the development of the 

spans shown. However, consideration should be given to finishes, partitions, 

walls, etc. when reading from the table. 

4. Based upon concrete densities at wet stage: normal weight concrete 2400 kg/ 

m 3 , lightweight concrete 1900 kg/m 3 . 

5. A span to depth ratio limit of 35:1 for normal weight concrete and 30:1 for 

lightweight concrete is generally used. Where isolated single spans occur, 

these should be reduced to 30:1 and 25:1 respectively. 

• Good pumping characteristics: 

When used in conjunction with the right mix design, 

STRUX ® 90/40 fibres display excellent pumping 

characteristics, minimising job downtime through equipment 

problems. 

Longitudinal shear strength 

For design in accordance with BS 5950: Part 3, the shear 

resistance of each shear plane of concrete reinforced with 

5.3 kg/m 3 of STRUX ® 90/40 fibres can be expressed as 

v r = 2A cv + v p 

Acv is the cross-sectional area of concrete per unit length of 

beam. Where the decking spans perpendicular to the span of 

the beam this area includes the concrete both above the profile 

and within the decking troughs. If the decking is spanning 

parallel to the beam then only the concrete above the profile 

should be considered to be resisting longitudinal shear. 

Acv 

Perpendicular 

To this longitudinal shear resistance may be added a 

component, vp, arising from the tensile strength of the deck, 

but only in the situation where the deck spans perpendicular 

to the beam and it is either continuous across the beam 

or anchored to it with through-deck welded shear studs. 

Guidance on the calculation of vp can be found in the 

appropriate section of BS 5950: Part 3. 

Shear stud resistance 

Acv 

Parallel 

Testing established that the performance of stud connectors 

was enhanced when embedded in specimens using concrete 

reinforced with 5.3kg/m 3 of STRUX ® 90/40 fibres, compared 

to identical specimens using conventional reinforcement bars. 

This was demonstrated by an improvement in both shear 

resistance and ductility and demonstrates that the BS 5950- 

3:1990 codified stud reduction factors (k) can be adopted 

without additional modification. 

6. Maximum deflection in the direction of span of the decking is limited to span/130 

after taking account of ponding. 

7. Construction stage design includes an allowance of 1.5kN/m 2 for construction 

loading. 

8. Composite slabs are designed to be simply supported irrespective of the deck 

support configuration. The STRUX ® 90/40 fibres are included to satisfy the 

minimum crack control and load distribution requirements of BS 5950: Part 4. 

9. S350 decking is manufactured from material meeting the specification: 

BS EN 10326-S350GD+Z275-N-A-C. It has guaranteed minimum yield 

strength of 350 N/mm2. 

19

20 

Holorib with STRUX ® 90/40 fibres 1hr Fire Rating 





Span/load/fire table Normal weight concrete 

Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

100 0.092 3.36 3.36 2.95 3.53 3.53 2.99 3.50 3.50 3.07 

120 0.112 3.19 3.19 3.19 3.35 3.35 3.35 3.66 3.66 3.59 

130 0.122 3.12 3.12 3.12 3.28 3.28 3.28 3.58 3.58 3.58 

150 0.142 2.99 2.99 2.99 3.14 3.14 3.14 3.44 3.44 3.44 

175 0.167 2.85 2.85 2.85 3.00 3.00 3.00 3.29 3.29 3.29 

200 0.192 2.74 2.74 2.74 2.89 2.89 2.89 3.16 3.16 3.16 

250 0.242 - - - - - - - - - 

100 0.092 3.50 3.39 2.85 3.50 3.50 2.99 3.50 3.50 3.07 

120 0.112 4.15 3.69 3.12 4.20 4.13 3.48 4.20 4.20 3.59 

130 0.122 4.30 3.84 3.25 4.55 4.29 3.63 4.55 4.55 3.85 

150 0.142 4.58 4.10 3.48 5.11 4.58 3.89 5.25 5.25 4.38 

175 0.167 4.87 4.39 3.75 5.43 4.90 4.19 6.13 5.90 5.02 

200 0.192 5.12 4.64 3.98 5.70 5.17 4.45 6.27 6.23 5.37 

250 0.242 - - - - - - - - - 

Span/load/fire table Lightweight concrete 

Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

100 0.092 3.00 3.00 2.77 3.00 3.00 2.81 3.00 3.00 2.88 

120 0.112 3.42 3.42 3.23 3.60 3.60 3.28 3.60 3.60 3.36 

130 0.122 3.34 3.34 3.34 3.52 3.52 3.52 3.84 3.84 3.61 

150 0.142 3.21 3.21 3.21 3.38 3.38 3.38 3.69 3.69 3.69 

175 0.167 3.07 3.07 3.07 3.23 3.23 3.23 3.53 3.53 3.53 

200 0.192 2.95 2.95 2.95 3.10 3.10 3.10 3.40 3.40 3.40 

250 0.242 - - - - - - - - - 

100 0.092 3.00 3.00 2.77 3.00 3.00 2.81 3.00 3.00 2.88 

120 0.112 3.60 3.60 3.16 3.60 3.60 3.28 3.60 3.60 3.36 

130 0.122 3.90 3.90 3.30 3.90 3.90 3.52 3.90 3.90 3.61 

150 0.142 4.50 4.21 3.55 4.50 4.50 3.97 4.50 4.50 4.11 

175 0.167 5.06 4.52 3.83 5.25 5.05 4.28 5.25 5.25 4.72 

200 0.192 5.34 4.79 4.08 5.95 5.35 4.56 6.00 6.00 5.33 

250 0.242 - - - - - - - - - 

STRUX ® 90/40 synthetic macro fibres are included in the concrete mix at a dosage rate of 5.3 kg/m 3 

Refer to notes on page 19 

the original: 

Holorib

Holorib with STRUX ® 90/40 fibres 1 1/2 hr Fire Rating 






Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

110 0.102 3.25 2.99 2.57 3.44 3.12 2.71 3.50 3.39 2.93 

120 0.112 3.19 3.11 2.68 3.35 3.26 2.83 3.66 3.54 3.07 

130 0.122 3.12 3.12 2.82 3.28 3.28 2.95 3.58 3.58 3.19 

150 0.142 2.99 2.99 2.99 3.14 3.14 3.14 3.44 3.44 3.43 

175 0.167 2.85 2.85 2.85 3.00 3.00 3.00 3.29 3.29 3.29 

200 0.192 2.74 2.74 2.74 2.89 2.89 2.89 3.16 3.16 3.16 

- - - - - - - - - 2.95 2.95 

110 0.102 3.25 2.99 2.57 3.45 3.12 2.71 3.75 3.39 2.93 

120 0.112 3.37 3.11 2.68 3.59 3.26 2.83 3.89 3.54 3.07 

130 0.122 3.55 3.24 2.82 3.71 3.39 2.95 4.03 3.68 3.19 

150 0.142 3.77 3.45 3.02 3.95 3.62 3.17 4.28 3.93 3.43 

175 0.167 4.02 3.70 3.26 4.20 3.87 3.41 4.55 4.19 3.69 

200 0.192 4.28 3.96 3.50 4.46 4.14 3.66 4.82 4.46 3.94 

250 0.242 - - - - - - - - - 


Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

105 0.097 3.15 3.07 2.62 3.15 3.15 2.75 3.15 3.15 2.98 

120 0.112 3.42 3.32 2.85 3.60 3.46 2.97 3.60 3.60 3.21 

130 0.122 3.34 3.34 2.99 3.52 3.52 3.12 3.84 3.84 3.37 

150 0.142 3.21 3.21 3.21 3.38 3.38 3.38 3.69 3.69 3.66 

175 0.167 3.07 3.07 3.07 3.23 3.23 3.23 3.53 3.53 3.53 

200 0.192 2.95 2.95 2.95 3.10 3.10 3.10 3.40 3.40 3.40 

- - - - - - - - - 3.18 3.18 

105 0.097 3.15 3.07 2.62 3.15 3.15 2.75 3.15 3.15 2.98 

120 0.112 3.60 3.32 2.85 3.60 3.46 2.97 3.60 3.60 3.21 

130 0.122 3.84 3.47 2.99 3.90 3.63 3.12 3.90 3.90 3.37 

150 0.142 4.14 3.76 3.25 4.32 3.93 3.39 4.50 4.23 3.66 

175 0.167 4.53 4.12 3.59 4.71 4.29 3.73 5.05 4.61 4.00 

200 0.192 4.90 4.50 3.93 5.09 4.66 4.07 5.43 4.97 4.35 

250 0.242 - - - - - - - - - 



21

22 

Holorib with STRUX ® 90/40 fibres 2hrs Fire Rating 






Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

125 0.117 3.12 2.80 2.46 3.25 2.96 2.59 3.59 3.25 2.84 

130 0.122 3.12 2.87 2.50 3.28 3.06 2.67 3.58 3.31 2.87 

150 0.142 2.99 2.99 2.73 3.14 3.14 2.86 3.44 3.44 3.10 

170 0.162 2.88 2.88 2.88 3.03 3.03 3.03 3.32 3.32 3.28 

175 0.167 2.85 2.85 2.85 3.00 3.00 3.00 3.29 3.29 3.29 

200 0.192 2.74 2.74 2.74 2.89 2.89 2.89 3.16 3.16 3.16 

250 0.242 - - - - - - - - - 

125 0.117 3.12 2.80 2.46 3.25 2.96 2.59 3.59 3.25 2.84 

130 0.122 3.20 2.87 2.50 3.34 3.06 2.67 3.62 3.31 2.87 

150 0.142 3.40 3.12 2.73 3.57 3.27 2.86 3.87 3.55 3.10 

170 0.162 3.57 3.29 2.89 3.74 3.44 3.03 4.05 3.73 3.28 

175 0.167 3.61 3.33 2.93 3.78 3.49 3.07 4.10 3.78 3.33 

200 0.192 3.82 3.53 3.13 4.00 3.70 3.27 4.32 4.00 3.54 

250 0.242 - - - - - - - - - 


Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

115 0.107 3.25 2.93 2.52 3.39 3.05 2.62 3.45 3.29 2.82 

120 0.112 3.32 2.99 2.57 3.46 3.12 2.68 3.60 3.37 2.89 

130 0.122 3.34 3.11 2.68 3.52 3.26 2.81 3.84 3.53 3.03 

150 0.142 3.21 3.21 2.90 3.38 3.38 3.03 3.69 3.69 3.28 

175 0.167 3.07 3.07 3.07 3.23 3.23 3.23 3.53 3.53 3.53 

200 0.192 2.95 2.95 2.95 3.10 3.10 3.10 3.40 3.40 3.40 

250 0.242 - - - - - - - - - 

115 0.107 3.25 2.93 2.52 3.39 3.05 2.62 3.45 3.29 2.82 

120 0.112 3.32 2.99 2.57 3.46 3.12 2.68 3.60 3.37 2.89 

130 0.122 3.44 3.11 2.68 3.60 3.26 2.81 3.90 3.53 3.03 

150 0.142 3.69 3.35 2.90 3.86 3.50 3.03 4.18 3.79 3.28 

175 0.167 3.99 3.64 3.17 4.16 3.80 3.30 4.49 4.09 3.56 

200 0.192 4.31 3.94 3.45 4.48 4.10 3.59 4.81 4.40 3.85 

250 0.242 - - - - - - - - - 



the original: 

Holorib

Ribdeck E60 with STRUX ® 90/40 fibres 1hr Fire Rating 






Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

130 0.094 3.31 3.00 2.58 3.44 3.11 2.68 3.69 3.33 2.87 

140 0.104 3.22 3.13 2.70 3.58 3.25 2.81 3.83 3.47 3.00 

150 0.114 3.14 3.14 2.82 3.49 3.37 2.93 3.81 3.60 3.12 

160 0.124 3.07 3.07 2.93 3.41 3.41 3.03 3.72 3.72 3.25 

175 0.139 2.96 2.96 2.96 3.30 3.30 3.22 3.61 3.61 3.43 

200 0.164 2.79 2.79 2.79 3.14 3.14 3.14 3.45 3.45 3.45 

250 0.214 - - - - - - - - - 

130 0.094 3.31 2.93 2.43 3.44 3.11 2.58 3.69 3.33 2.85 

140 0.104 3.45 3.07 2.54 3.58 3.25 2.71 3.83 3.47 3.00 

150 0.114 3.57 3.20 2.66 3.71 3.37 2.84 3.96 3.60 3.12 

160 0.124 3.69 3.32 2.77 3.83 3.49 2.96 4.09 3.73 3.25 

175 0.139 3.88 3.50 2.92 4.02 3.68 3.13 4.29 3.93 3.43 

200 0.164 4.18 3.76 3.15 4.32 3.98 3.40 4.60 4.23 3.71 

250 0.214 - - - - - - - - - 


Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

120 0.084 - - - - - - - - - 

130 0.094 3.50 3.14 2.59 3.64 3.26 2.76 3.89 3.49 2.98 

140 0.104 3.44 3.30 2.72 3.81 3.43 2.91 4.07 3.66 3.13 

150 0.114 3.36 3.36 2.87 3.73 3.57 3.07 4.08 3.81 3.27 

175 0.139 3.19 3.19 3.19 3.55 3.55 3.40 3.88 3.88 3.62 

200 0.164 3.04 3.04 3.04 3.39 3.39 3.39 3.70 3.70 3.70 

250 0.214 - - - - - - - - - 

120 0.084 - - - - - - - - - 

130 0.094 3.43 2.99 2.46 3.64 3.21 2.62 3.89 3.49 2.89 

140 0.104 3.59 3.13 2.58 3.81 3.37 2.75 4.07 3.66 3.05 

150 0.114 3.75 3.27 2.70 3.96 3.53 2.89 4.22 3.81 3.22 

175 0.139 4.11 3.60 2.98 4.34 3.90 3.20 4.61 4.18 3.60 

200 0.164 4.42 3.89 3.23 4.69 4.23 3.48 4.97 4.53 3.94 

250 0.214 - - - - - - - - - 



less concrete 

Ribdeck E60 

23

24 

Ribdeck 80 with STRUX ® 90/40 fibres 1hr Fire Rating 






Support 

Condition 

longer spans 

Ribdeck 80 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

140 0.098 3.24 3.06 2.79 3.34 3.14 2.88 3.51 3.30 3.02 

150 0.108 3.46 3.26 2.96 3.56 3.35 3.05 3.73 3.52 3.21 

160 0.118 3.68 3.46 3.12 3.78 3.57 3.22 3.95 3.74 3.41 

170 0.128 3.73 3.65 3.25 4.00 3.76 3.38 4.18 3.95 3.59 

175 0.133 3.69 3.69 3.32 4.10 3.85 3.45 4.29 4.05 3.67 

200 0.158 3.50 3.50 3.50 3.92 3.92 3.75 4.60 4.52 4.03 

250 0.208 3.20 3.20 3.20 3.58 3.58 3.58 4.23 4.23 4.23 

140 0.098 3.24 3.06 2.79 3.34 3.14 2.88 3.51 3.30 3.02 

150 0.108 3.46 3.26 2.96 3.56 3.35 3.05 3.73 3.52 3.21 

160 0.118 3.68 3.46 3.12 3.78 3.57 3.22 3.95 3.74 3.41 

170 0.128 3.89 3.65 3.25 4.00 3.76 3.38 4.18 3.95 3.59 

175 0.133 3.99 3.74 3.32 4.10 3.85 3.45 4.29 4.05 3.67 

200 0.158 4.43 4.10 3.60 4.58 4.25 3.75 4.82 4.52 4.03 

250 0.208 5.07 4.71 4.18 5.25 4.87 4.32 5.59 5.18 4.60 


Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

130 0.088 3.16 2.93 2.66 3.25 3.02 2.72 3.47 3.21 2.88 

140 0.098 3.39 3.17 2.86 3.49 3.25 2.94 3.68 3.43 3.10 

150 0.108 3.63 3.40 3.07 3.72 3.49 3.16 3.89 3.65 3.32 

160 0.118 3.87 3.63 3.25 3.96 3.72 3.36 4.14 3.89 3.53 

175 0.133 3.96 3.95 3.49 4.33 4.06 3.62 4.50 4.24 3.83 

200 0.158 3.77 3.77 3.77 4.22 4.22 3.98 4.95 4.79 4.25 

250 0.208 3.47 3.47 3.47 3.89 3.89 3.89 4.58 4.58 4.58 

130 0.088 3.16 2.93 2.66 3.25 3.02 2.72 3.47 3.21 2.88 

140 0.098 3.39 3.17 2.86 3.49 3.25 2.94 3.68 3.43 3.10 

150 0.108 3.63 3.40 3.07 3.72 3.49 3.16 3.89 3.65 3.32 

160 0.118 3.87 3.63 3.25 3.96 3.72 3.36 4.14 3.89 3.53 

175 0.133 4.23 3.95 3.49 4.33 4.06 3.62 4.50 4.24 3.83 

200 0.158 4.78 4.40 3.83 4.91 4.54 3.98 5.11 4.79 4.25 

250 0.208 5.60 5.14 4.50 5.78 5.31 4.65 6.11 5.63 4.93 


Refer to notes on page 19

Ribdeck AL with STRUX ® 90/40 fibres 1hr Fire Rating 






Support 

Condition 

shallow slabs 


Ribdeck AL 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

120 0.095 3.25 2.93 2.50 3.41 3.07 2.62 3.70 3.34 2.86 

130 0.105 3.19 3.07 2.64 3.44 3.21 2.76 3.71 3.47 2.99 

140 0.115 3.12 3.12 2.75 3.36 3.32 2.88 3.62 3.60 3.11 

150 0.125 3.05 3.05 2.86 3.28 3.28 2.99 3.54 3.54 3.23 

175 0.150 2.88 2.88 2.88 3.12 3.12 3.12 3.37 3.37 3.37 

200 0.175 2.73 2.73 2.73 2.99 2.99 2.99 3.23 3.23 3.23 

120 0.095 3.25 2.93 2.50 3.41 3.07 2.62 3.70 3.34 2.86 

130 0.105 3.39 3.07 2.64 3.54 3.21 2.76 3.84 3.47 2.99 

140 0.115 3.50 3.18 2.75 3.67 3.32 2.88 3.96 3.60 3.11 

150 0.125 3.62 3.29 2.86 3.78 3.44 2.99 4.09 3.72 3.23 

175 0.150 3.95 3.61 3.16 4.12 3.77 3.29 4.43 4.06 3.54 

200 0.175 4.23 3.89 3.43 4.40 4.05 3.56 4.71 4.34 3.82 


Support 

Condition 



(mm) (m3 /m2 ) 5.0 6.7 10.0 5.0 6.7 10.0 5.0 6.7 10.0 

110 0.085 3.27 2.92 2.48 3.30 3.06 2.60 3.30 3.30 2.80 

120 0.095 3.43 3.07 2.62 3.59 3.21 2.74 3.60 3.47 2.96 

130 0.105 3.41 3.22 2.75 3.69 3.37 2.88 3.90 3.64 3.10 

150 0.125 3.27 3.27 3.00 3.53 3.53 3.14 3.81 3.81 3.38 

175 0.150 3.11 3.11 3.11 3.35 3.35 3.35 3.62 3.62 3.62 

200 0.175 2.97 2.97 2.97 3.21 3.21 3.21 3.47 3.47 3.47 

110 0.085 3.27 2.92 2.48 3.30 3.06 2.60 3.30 3.30 2.80 

120 0.095 3.43 3.07 2.62 3.59 3.21 2.74 3.60 3.47 2.96 

130 0.105 3.59 3.22 2.75 3.75 3.37 2.88 3.90 3.64 3.10 

150 0.125 3.88 3.50 3.00 4.05 3.65 3.14 4.36 3.93 3.38 

175 0.150 4.29 3.89 3.36 4.46 4.05 3.50 4.78 4.34 3.75 

200 0.175 4.64 4.23 3.68 4.81 4.38 3.81 5.13 4.68 4.06 



25

26 

Guidelines for concrete producers 

The following guidelines are designed to assist concrete producers with the efficient batching 

and dispersion of STRUX ® 90/40 synthetic structural fibres and to provide concrete that has the 

optimum pumping, placing and finishing characteristics for composite floor slab construction. 

1. Mix design 

1.1 The dosage of STRUX ® 90/40 for this application has been set 

at 5.3kg/m 3 . This has been determined by extensive research 

programmes into the behaviour of composite floors using Richard 

Lees Steel Decking profiles and must not be altered without 

engineering approval. The addition of fibres will reduce the 

workability and the apparent paste volume of the concrete. In order 

to supply a concrete with optimum pumping, placing and finishing 

characteristics, these effects will need to be addressed by attention 

to the mix design and the selection of an appropriate and proven 

superplasticising admixture. The recommended admixture for this 

application is ADVA ® , supplied by Grace Construction Products. 

1.2 Typically we suggest that an optimum paste volume for concrete 

with 5.3kg/m 3 of STRUX ® 90/40 would be achieved with a 

cementitious content of 360kg and a coarse to fines ratio set at 

45%. Where possible, trial mixes should be performed to determine 

a suitable mix and Grace Construction Products will provide 

technical advice where requested. 

1.3 The exact water content and admixture dose are best determined 

experimentally. 

2. Dry batching 

2.1 STRUX ® 90/40 synthetic structural fibres are supplied in concrete 

dispersible bags; either 0.5kg or 2.3kg. The whole bags can be 

added into the mixing operation without the need to open them. 

The appropriate number of bags can be added to the empty truck 

prior to loading with concrete. A suitable safe loading platform or 

safety steps should be provided to give the operator secure access 

to the mixer truck. 

www.rlsd.com 

2.2 Once the STRUX ® 90/40 bags have been loaded, 200 litres of 

water should then be added. This water addition assists the 

bags to break up, releasing their contents. 

2.3 On completion of the weighing of the aggregates into the weigh 

hopper, a small amount (e.g. 0.5 - 1.0 tonne) of preferably coarse 

aggregates should be released into the truck. The contents (now 

containing the full quantity of fibres, ~ 200 litres of water and a 

portion of the aggregates alone) should be mixed for 2 - 3 minutes 

to allow the coarse aggregates to abrade and disperse the 

fibres thoroughly. 

2.4 The remaining aggregates and cementitious materials can now 

be loaded into the truck along with further water. Mixing should 

now proceed as usual, targeting an initial slump of 50 - 70mm, 

before the addition of ADVA ® . Once this has been achieved, the 

appropriate dosage of ADVA ® should be added to increase the 

workability to 140 - 180mm. 

3. Wet mixing 

3.1 In wet mixed plants the bags of STRUX ® 90/40 are normally added 

directly into the mixer prior to charging with aggregates. 

However this procedure may depend on the mixer and overall plant 

specifications and it is recommended that Grace Construction 

Products are consulted for advice on the best method of fibre 

addition.

Guidelines for contractors 

These guidelines are designed to provide contractors with advice on how best to pump, place, compact and finish 

concrete containing STRUX ® 90/40 synthetic structural fibre reinforcement for composite floor slab construction. 

1. Concrete pumping 

1.1 Mix Design and Workability 

When STRUX ® 90/40 is used in concrete for Holorib and Ribdeck 

composite floor slabs it is always used at a fixed dosage of 

5.3kg/m 3 . This requires careful attention to mix design in order 

to ensure that there is sufficient paste volume to coat the fibres 

fully. In general we recommend a pump mix with a minimum fine 

aggregate to coarse aggregate ratio of 45%. 

STRUX ® 90/40 reinforced concrete should be delivered and 

discharged into the pump hopper at a workability of between 

2. Concrete placing, compacting and finishing operations 

2.1 Placing the concrete 

Placing and levelling STRUX ® 90/40 reinforced concrete should be 

carried out exactly as per normal concrete. The high dosage of fibre 

reinforcement in the concrete may give the apparent appearance 

of over cohesiveness, but raking/levelling will not be affected and 

will require no more than usual effort. Additionally, where ADVA ® 

Floor 200 has been used, this will assist the concrete in levelling, 

compaction and finishing. 

2.2 Compacting the concrete 

The best plant suited for compacting fibre reinforced concrete is 

the ‘Magi Screed’ as figure 1; 

The concrete should be compacted sufficiently to ensure that 

adequate paste is brought to the surface to allow easy finishing, 

particularly when power floating. If this method of applying some 

form of surface vibration to the fibre reinforced concrete is not 

used, then a high number of fibres will appear at the surface of 

the concrete. This may not be an issue if the concrete floor is 

being covered by insulation etc. but if the specified finish is 

power floating, then the use of the Magi Screed greatly 

assists in achieving a satisfactory surface. 

figure 1 figure 2 

figure 3 

140mm - 180mm, i.e. high enough to allow the concrete to fall 

through the hopper grill without stacking up, but not so high as to 

promote segregation of the concrete in the pump line, particularly 

while pumping has ceased during concrete truck change-over. An 

approved superplasticising admixture must be used to reinstate the 

workability lost through the addition of fibres. Grace Construction 

Products strongly recommends that ADVA ® be used, which also 

provides lubrication to the concrete, reducing pumping pressures. 

2.3 Finishing the concrete surface 

After compaction with the Magi Screed, an easy float (refer figure 2) 

is usually passed over the concrete to close up the surface. 

2.4 Once the fibre reinforced concrete has been levelled, 

compacted and floated, it is allowed to cure in accordance with 

good concreting practice. If a power float finish has been specified, 

then the surface of the concrete floor is usually closed up using 

a “panning” operation, followed by the floating operation 

as shown in figure 3. 

If the type of floating machine shown in figure 3 is used, then some 

fibres will be seen in the surface of the finished concrete floor. 

If a ride-on machine is used (refer figure 4), then usually all of the 

fibres disappear during the floating operation. 

figure 4 

27

28 

RLSD Shaping the London Skyline 

30 St. Mary Axe - The Gherkin 

www.rlsd.com 

Location: 

30 St Mary Axe, London, 

England, United Kingdom 

Status: Complete 

Completion Date: 2004 

Height: 180 metres 

Floor Area: 

70,000 square metres 

Architect: Foster & Partners 

Steel Contractor: 

Victor Buyck – Hollandia JV 

RLSD Profile: Ribdeck 80 

Widely known throughout the world by 

the nickname ‘The Gherkin’, 30 St Mary 

Axe stands at 180 metres tall, making it on 

completion the second tallest building in the 

City of London and the sixth tallest in the 

Greater London region. 

Thanks to the efficiency of it’s 

environmentally-conscious design, The 

Gherkin uses half the power that a similar 

tower would typically consume, whilst the 

unique triangulated perimeter structure 

makes this tall building sufficiently stiff 

to control wind-excited sways without 

requiring any additional cross-bracing. 

The specification of Ribdeck 80 for this 

project was an integral factor in achieving 

the ambitious design of this unique building, 

with its radial steel beam arrangement 

requiring a decking profile that could span 

up to 4.75m without any requirement for 

additional framing or temporary support. 

Ribdeck 80 was the obvious choice.


The Emirates Stadium, London 

The Emirates Stadium 

– home of Arsenal 

Football Club – is 

the second largest 

stadium in the Premier 

League, and is widely 

acknowledged as 

being one of the finest 

sporting venues in 

the world. 

The stadium is a 

four-tiered bowl 

that creates an 

amphitheatre type arena, with roofing spanning around the curved stands. 

With any modern sporting venues, it was essential to minimise the number 

of obstructions that could detract from the viewing experience. 

Location: 

Ashburton Grove, London, 





Floor Area: 


Architect: HOK Sport 


Watson Steel Structures 


29

30 


Canary Wharf 

Location: Isle of Dogs, London, England, United Kingdom 

Status: Incomplete 

Completion Date: Ongoing 

Height: 235 metres (highest point) 

Floor Area: See panel opposite 

Architect: Various 

Steel Contractor: Various 

RLSD Profile: See panel opposite 

www.rlsd.com 

13 

9 

Canary Wharf is a large business and shopping development 

in London, located on the Isle of Dogs in the London Borough 

of Tower Hamlets, centred on the old West India Docks in the 

London Docklands. When topped out in 1990, One Canada 

Square became the UK’s tallest building and a powerful 

symbol of the regeneration of Docklands, as well as being an 

imposing architectural presence on the London skyline. 

During the various phases of construction at Canary Wharf, 

RLSD have supplied over 800,000 square metres of decking 

profile – testament to the quality of service and the superiority 

of the profiles that we have supplied over the years. 

8 

7 

6 

12

1 

10 

5 

11 

4 

2 

1 1 Canada Square - 147,000 m 2 Ribdeck 60 

2 8 Canada Square - 101,700 m 2 Ribdeck AL 

3 5 Churchill Place - 38,500 m 2 Ribdeck E60 

4 20 Churchill Place - 38,700 m 2 Ribdeck E60 

5 25 North Colonnade - 34,000 m 2 Ribdeck 60 

6 30 South Colonnade - 35,000 m 2 Ribdeck 60 

7 20 Cabot Square & 10 South Colonnade 

- 68,000 m 2 Ribdeck 60 

3 

8 25 Cabot Square - 60,000 m 2 Ribdeck 60 

9 40 Bank Street - 71,700 m 2 Ribdeck AL 

10 1 Cabot Square - 65,000 m 2 Ribdeck 60 

11 10 Cabot Square & 5 North Colonnade 

- 75,000 m 2 Ribdeck 60 

12 15 Westferry Circus - 23,500 m 2 Ribdeck AL 

13 20 Bank Street - 59,300 m 2 Ribdeck AL 

Total decking supplied: 817,400 m2 

31

32 


Willis Building 

Location: 

51 Lime Street, London, 





www.rlsd.com 

Floor Area: 


Architect: Norman Foster 


William Hare 


The Willis Building stands opposite the 

famous Lloyd’s building in the heart of 

the City of London. The building features 

an iconic “stepped” design, which was 

intended to resemble the shell of a 

crustacean, with setbacks rising at 97 and 

68 metres respectively. 

Constructed between 2004 and 2007, it was 

a significant addition to the London skyline, 

becoming the third tallest building in the 

City after 30 St Mary Axe and CityPoint. 

The core was topped out in July 2006, 

with Ribdeck 80 specified throughout the 

structure primarily due to its excellent load 

carrying properties and unrivalled ability to 

carry long unpropped spans. 51 Lime Street 

is the first in a wave of new skyscrapers 

planned for the area.


St Pancras International, London 

The £800m redevelopment, extension and 

re-branding of St Pancras International 

echoes the opulence of New York’s Grand 

Central Station, and features a wide 

range of top quality retail stores, as well 

as Europe’s longest champagne bar, and 

even a daily fresh farmers’ market. 

Famed for it’s recently introduced Eurostar 

train service to continental Europe, the 

need to accommodate the unusually long 

Eurostar trains necessitated the extension 

of the architecturally iconic Barlow Shed. 

Longer trains also means longer platforms 

and longer decking spans. RLSD were the obvious choice for providing decking profiles 

capable of spanning great lengths without compromising load carrying capacity. 

Location: 

St Pancras, London, 



Completion Date: 

November 2007 

Floor Area: 


Architect: 

Rail Link Engineering 


Watson Steel Structures 

RLSD Profile: 

Holorib, Ribdeck 80 

33

34 

RLSD Architectural Impact Across the UK 

Civil Justice Centre (Manchester) 

www.rlsd.com 

Location: 

Spinningfields, Manchester, 





Floor Area: 


Architect: 

Denton Corker Marshall 


William Hare 

RLSD Profile: Holorib 

This distinctive building is widely 

recognisable for the ‘fingers’ at each end 

that are cantilevered over the lower levels - 

it is rumoured that architect Barrie Marshall 

sketched the entire building by hand and 

that very little has deviated from his original 

drawings. On the west side of the building 

is an imposing 11,000 m2 suspended glass 

wall - the largest in Europe. 

The specification of Holorib throughout 

the building was an important factor in 

minimising the construction depth of the 

floor slab to suit the architect’s vision of the 

slender form of the ‘finger’ protrusions at 

each end of the building.


Wales Millennium Centre, Cardiff 

The Wales Millennium Centre is a national 

centre for performing arts. The architect’s 

concept of the building was to design 

a structure that expressed “Welshness” 

and that was instantly recognisable and 

distinctive across Europe. 

The building was designed to reflect the 

many different parts of Wales with local 

Welsh materials that dominate its history; 

slate, metal, wood and glass. With Ribdeck 

80 being produced in a factory just 15 miles from the Millennium Centre the specification 

of this profile went some way to further enhancing the building’s “Welshness”. 

As a performing arts centre, clearly the acoustics of the building would play an integral 

part in its success as a venue – the specification of Ribdeck 80 allows the internal 

structure to be acoustically isolated from the main frame, with additional decking 

used in the roof to shield aircraft noise. 

Location: Cardiff Bay, 

Cardiff, Wales 



Seating Capacity: 1,900 

Floor Area: 


Architect: 

Capita Architecture 


Watson Steel 


35

36 


Spinnaker Tower, Portsmouth 

www.rlsd.com 

Location: 

Portsmouth Harbour, 

Portsmouth, 

United Kingdom 




Floor Area: 


Architect: HGP Architects 

Steel Contractor: Butterley 


The Spinnaker Tower is the centrepiece of 

the redevelopment of Portsmouth Harbour, 

and was chosen by Portsmouth residents 

from a selection of concept designs. 

The tower reflects Portsmouth’s maritime 

history, representing sails billowing in the 

wind – a design accomplished using two 

large, sweeping steel arcs. 

An imposing and stunning addition to the 

Portsmouth horizon, Spinnaker Tower 

is the tallest accessible structure in the 

United Kingdom outside London, with three 

observation platforms constructed from 

Ribdeck 80 affording glorious views of up to 

23 miles.


The Curve – Leicester Performing Arts Centre 

Location: 

Rutland Street, Leicester, 

United Kingdom 



Floor Area: 


Architect: 

Rafael Vinoly Architects 


William Hare 


Based in the 

redeveloped Cultural 

quarter in Leicester 

City Centre, the Curve 

theatre opened in 

Autumn 2008, and 

is one of the main 

flagship projects in the 

regeneration of the city. 

This ambitious and 

innovative design has 

complete architectural 

transparency, with the weight of the structure suspended from the roof of the building. 

The long spanning capacity of Ribdeck 80 allowed the number of steel members in the 

structure to be kept to a minimum, emphasising the light and airy form of the structure. 

37

38 

Guidance notes for Design and fixing 

DESiGn PAGES 38-39 

General 38 

Construction Loading 38 

Permanent Loading 38 

Reinforcement 38 

Deflection 38 

Temporary Support 39 

Durability 39 

Full Lateral Restraint 39 

Diaphragm Action 39 

Composite Beams 39 

Perimeter Beams 39 

Transverse Reinforcement 39 

Shear Studs 39 

Reference Literature 39 

DELIVERy PAGE 40 

Delivery, Transportation and Access 40 

Identification 40 

Lifting and Storage 40 

General 

RLSD’s structural decking can be used as permanent shuttering 

to an in situ concrete topping, or as both shuttering and tensile 

reinforcement to form what is referred to as a composite floor slab. 

Composite floor slabs form the most frequent application and these 

are designed to the currently applicable design codes (principally 

BS5950: Part 4). A slab design appropriate to the required application 

can be selected by a suitably qualified person from reference to 

either RLSD’s span/load tables or using Deckspan software, both 

of which are available free of charge at www.rlsd.com. When 

decking is used as permanent shuttering only it is the responsibility 

of the Project Structural Design Engineer to specify all the slab 

reinforcement necessary to support the permanent loads, ignoring 

any contribution from the decking profile. 

Construction Loading 

The RLSD design span/load tables generally make allowance for 

a temporary construction live load of 1.5kN/m 2 in addition to the 

wet weight of concrete. This should not be exceeded without 

consultation with the RLSD Technical Advisory Service. The heaping 

of concrete during placement should be avoided. In the unpropped 

condition it is normally the construction stage that governs the 

allowable spans shown in the tables. 

Construction Loading after Initial Concrete Set 

The slab strength will generally have been specified by the Project 

Structural Design Engineer on the basis of support of long-term 

loads consistent with the building’s intended use. In the temporary 

condition, construction loads from plant used for erecting steelwork 

or from materials stored for following trades may constitute a more 

onerous design condition and should be referred back to the Project 

Structural Design Engineer for assessment. 

Permanent Loading 

The self weight of the slab has been taken into account in the design 

process and need not be included in the imposed loads indicated 

in the span/load tables. The Project Structural Design Engineer 

should sum all predominantly uniform applied live, partition, finishes 

www.rlsd.com 

PROFESSIONAL 

fixinG PAGES 40-42 

Installation Service 40 

Health & Safety 40 

Fall Arrest 40 

Fixing and Securing 41 

Cartridge Tools 41 

Site Testing 41 

Edge Trim 41 

Cantilevered Deck and Trim 42 

Decking on Shelf Angles 42 

Decking Around Columns 42 

Minimising Concrete Loss 42 

Concrete Encased Perimeter 

Steel Beams 42 

SHEAR STUDS PAGE 43 

Spacing of Shear Studs 43 

Preparation of Steel Flanges 43 

Stud Installation Equipment 43 

Installation and Testing 43 

PRIOR TO CONCRETE 

PLACEMENT PAGE 44 

Forming Openings 44 

Cleaning the Decking 44 

CONCRETE 

PLACEMENT PAGE 44 

Temporary Props 44 

Construction Joints 44 

Placing and Compacting 44 

Curing 44 

COMPOSITE 

FLOOR SLAB PAGE 45 

Soffit Fixings 45 

Holowedge and Ribwedge R80 45 

Alphawedge 45 

GOOD PRACTiCE: These guidance notes have been developed by RLSD during our many years in the Steel Decking Industry. 

Whilst every effort has been made to ensure that they are comprehensive, we would refer you to the BCSA publication No 37/04 – 

BCSA Code of Practice for Metal Decking and Stud Welding – for further guidance. These notes should also be read in conjunction 

with the prevailing national design guidance and health and safety legislation. 

DESiGn 

and loads when reading from these tables. Any walls other than 

lightweight partitions should be considered separately as either line 

or concentrated loads, and specific calculations should be made to 

check the adequacy of the selected slab to support them. 

Reinforcement 

In all circumstances appropriate crack control and distribution 

reinforcement should be provided within the slab and this can be in 

the form of a wire-welded mesh or, in certain situations, as synthetic 

macro fibres. This reinforcement may also be sufficient to provide 

the necessary fire resistance for the slab and this can be checked by 

reference to the RLSD tables for the Simplified Fire Design Method, 

available in literature and on the RLSD website. Where the design 

criteria are not covered by the simplified tables, then reinforcing bars, 

positioned in the decking troughs, will be required, the exact quantity 

being determined using RLSD’s Deckspan software or by reference 

to the Steel Construction Institute publication 056. 

Decking can only contribute to the transverse shear reinforcement 

for the distribution of longitudinal shear forces in composite beams 

when it is spanning perpendicular to the beam. In addition it should 

either be continuous across the beam, or the beam flange be wide 

enough to allow effective anchorage of the deck using shear studs 

welded in a staggered pattern. 

Additional reinforcement may also be required to comply with 

building or other regulations and it is the customer’s responsibility 

to ensure that the necessary design checks and approvals have 

been granted. 

Deflection 

Decking will deflect under the weight of wet concrete as it is placed. 

The design process takes account of this deflection and limits it 

in accordance with the relevant code of practice. The additional 

weight of concrete due to this deflection is factored into this and 

all subsequent calculations. No account is taken in RLSD’s tables 

or software for any deflection of the supporting steel frame. Those 

responsible for the placement of the concrete should be made aware 

of all expected deflections when assessing concrete volumes and 

finishing techniques.

Temporary support 

Temporary support may sometimes be necessary to sustain the dead 

weight of wet concrete and any other construction loads. General 

guidance is provided by RLSD in the form of span/load tables 

and Deckspan software and, where provided, on project specific 

installation layout drawings and design calculations. The Project 

Structural Design Engineer may also specify temporary propping in 

situations where tighter control on deflections is deemed necessary. 

The design and safe installation of temporary supports, including 

any bracing necessary, is the responsibility of the Project Structural 

Design Engineer. There should be continuous sole and header plates 

across the full width of every propped bay and the system should 

be installed so as to ensure zero deflection of the deck at propped 

points prior to concrete placement. The header plate should offer a 

wide area of support so as not to locally compromise the structural 

integrity or the appearance of the decking. 

Except where specifically advised by RLSD’s Technical Department, 

all temporary props to unsupported slab edges are to be fully in place 

prior to installation of the edge trim or decking. The same condition 

also applies to internal props meeting the conditions set out in Table 1. 

Profile Span 

Holorib >= 4.0 m 

Ribdeck AL >= 4.0 m 

Ribdeck E60 >= 4.0 m 

Ribdeck 80 >= 4.5 m 

Table 1: Lower Limit for Pre-installation of Temporary Supports. 

Temporary supports should remain in place until the concrete has 

reached a minimum of 70% of its characteristic strength. 

Durability 

Decking is produced from galvanised steel strip to BS EN 10326 

with a standard Z275 coating. When used in a dry and unpolluted 

environment, such as is the case in the majority of offices, 

warehouses, hospitals, and schools etc, a design ‘life to first 

maintenance’ of 20 - 50 years can be expected. Recent documented 

research would suggest that the predicted performance is likely to 

approach the higher end of this range. 

Full Lateral Restraint 

Guidance on lateral stability of beams can be obtained from SCI 

publication 093. Positive connection between the composite floor slab 

and the compression flange of a steel support beam may be achieved 

using either ENP2 or DAK 16 nails. These nails are capable of resisting 

lateral forces as required by BS 5950: Part 1, with safe working loads 

per nail indicated for differing sheet thicknesses in Table 2. 

Deck Thickness ENP2 DAK 16 

(mm) Shear (kN) Shear (kN) 

0.8 2.3 0.8 

0.9 2.7 0.8 

1.0 3.0 0.8 

1.1 3.5 0.8 

1.2 4.0 0.8 

Table 2: Safe Working Load per Nail 

As examples, values for lateral restraint with 0.9mm thickness 

decking are: 

a) with nails at 333mm centres at sheet ends 

ENP2 = 8.10 kN/m DAK 16 = 2.40 kN/m 

b) with nails at 666mm centres at intermediate support 

ENP2 = 4.05 kN/m DAK 16 = 1.20 kN/m 

Diaphragm Action 

Guidance on diaphragm action of steel decking during construction 

can be obtained from the SCI Advice Note AD175 (1995) and by 

reference to BS 5950: Part 9. 

Composite Beams 

Guidance on the design of composite beams is given in BS5950: 

Part 3: Section 3.1. Within the design there is a requirement for the 

provision of transfer of horizontal shear forces between the steel 

beam and the concrete slab. This is commonly achieved with the 

use of headed shear studs welded through the decking panels to the 

underlying beam top flange. 

The Project Structural Design Engineer should ensure that sufficient 

studs can be welded within the confines of the metal decking troughs 

to achieve the required degree of shear connection. In particular it is 

important to avoid the specification of beams with top flanges that 

are too thin and/or too narrow to accept off-centre welded studs. 

(Refer to Shear Studs section for further guidance - page 43). 

Perimeter Beams 

If perimeter beams, and beams adjacent to internal slab openings, 

are to be designed as composite ‘L’ beams, then the edge of the 

slab should extend a minimum distance of 6 times the stud diameter 

beyond the beam centreline. In most cases this will equate to a 

minimum distance of 114mm. If this condition is satisfied but does 

not exceed 300mm, then reinforcement should be specified in 

the form of ‘U’ bars detailed below the heads of the studs. If the 

edge distance exceeds 300mm, then the composite beam may 

be designed as an internal beam (albeit with reduced effective 

composite flange width) and reinforcement added as required to 

satisfy longitudinal shear transmission rules. 

Transverse Reinforcement 

The concrete flange of a composite beam is subjected to splitting 

forces and these may be resisted in part by contributions from the 

concrete, decking, top mesh and any additional steel bars crossing 

the beam perpendicular to the span direction. Any contribution 

from the decking should only be considered where the decking 

spans onto the beam and is either continuous across or is securely 

anchored to it with through deck welded shear studs. The decking 

contribution should be ignored where it spans parallel to the 

composite beam being considered. Any shortfall in transverse shear 

resistance is normally compensated for by the design and inclusion 

of additional reinforcement bars. 

Shear Studs 

Shear studs are manufactured from low carbon steel with minimum 

values of yield point of 350 N/mm2 , ultimate tensile strength 

450 N/mm2 , and elongation 15%. The studs should be headed and 

for through deck welding they should be specified with a shank 

diameter of 19mm. Studs should protrude a minimum of 35mm 

above the shoulder of the decking profile and the covering of 

concrete over the head of the stud should be a minimum of 15mm. 

The shear capacity of headed studs embedded in solid concrete is 

tabulated in BS 5950:Part 3:Section 3.1. In composite slabs the studs 

may be affected by the proximity of the webs of the steel decking sheet 

and their capacity may be reduced. Refer to BS5950:Part 3:Section 3.1 

for reduction factor formulae. 

Reference Literature 

• MCRMA Technical Paper 13 / SCI Publication P300: 

Composite Slabs and Beams Using Steel Decking: 

Best Practice for Design and Construction. 

• BCSA Publication 37/04: 

Code of Practice for Metal Decking and Stud Welding. 

• BS 5950: Structural Use of Steelwork in Building. 

39

40 

DELIVERy 

Delivery, Transportation and Access 

Loads are normally delivered by articulated vehicles of approximately 

16 metres in length and with maximum gross weights of up to 36 

tonnes. Decking will normally be delivered in full loads. Suitable 

access to and from unloading points on sites must be provided 

and maintained by the client. Delivery vehicles have a maximum 

unloading time of 2 hours. Unless otherwise agreed in writing 

before delivery, offloading and lifting to level and position is the 

responsibility of the customer. 

Deck Width (mm) Height (mm) 

Holorib 680 525 

Ribdeck E60 1020 175 

Ribdeck AL 910 200 

Ribdeck 80 620 350 

Table 3: Approximate Maximum Sizes of Bundles 

Bundle length will depend on decking panel lengths. Export/shipped 

bundles may differ – please ask for details. 

Lengths of decking manufactured in accordance with RLSD layout 

drawings or customer schedules are normally consolidated into 

compact, banded bundles as shown in Table 3. These bundles may 

weigh up to 2 tonnes and cover an effective area up to 100 square 

metres when laid, depending on the profile, gauge and length of 

the panels being delivered. Table 4 gives the mass per linear metre 

(kg/m) of each profile and gauge to assist in the calculation of 

individual bundle weights. 

Deck 

Gauge of Steel 

Table 4: Mass of Deck Panels (kg/m) 

The maximum sheet length on a particular project could be governed 

by one or more of the following: manual handling limitations, support 

configuration, transportation and access for loading deck bundles 

onto the steel frame. 

INSTALLATION 

Except in situations where fixing is contracted to RLSD, it is the customer 

who is responsible for the safe execution of the works. 

All users, installers and persons working in the proximity of the decking 

should be made familiar with the recommendations in this section. 

Installation Service 

RLSD provides the UK’s most experienced and professional 

installation service. Operating throughout the country, installing 

decking on projects ranging from 10m 2 to over 100,000m 2, 

RLSD can provide fully-trained construction teams backed by expert 

safety, construction and technical departments. The company also 

boasts externally-accredited management systems for health, safety 

and the environment to OHSAS 18001 and ISO 14001. 

Health and Safety 

Decking is manufactured to ISO 9001 from high yield steel coated with 

zinc and may be covered with a soluble protective lubricant which does 

not adversely affect performance. The sheets will have sharp edges 

and corners. COSHH data sheets are available for all hazards/activities 

associated with the handling and fixing of RLSD decking. 

Fall Arrest 

It is recommended that appropriate fall arrest systems are used. 

Generally safety netting is advised for steel-framed structures; air 

bags or similar for other structures. Details of the appropriate fall 

arrest system, together with a risk assessment covering the safety 

system installation method, should be included in the detailed 

installation method statement prepared by the decking installer prior to 

commencement of work. 

www.rlsd.com 

0.9 1.0 1.1 1.2 

Holorib 8.0 8.9 9.8 10.6 

Ribdeck E60 9.3 10.3 11.3 12.4 

Ribdeck AL 8.7 9.6 10.6 11.5 

Ribdeck 80 6.8 7.5 8.3 9.0 

Identification 

Where appropriate, bundles will be marked to correspond with RLSD 

layout drawings, with a bundle label identifying the product, the site, 

and a schedule reference code. To further aid identification, each 

panel of decking has its gauge and yield stress stamped in the base 

of the trough on the overlap return side of the sheet and each bundle 

has a paint splash colour identification code on one side as 

shown in table 5. 

Steel Yield Gauge of Steel (mm) 

Stress 0.9 1.0 1.1 1.2 

S350 BLUE/ YELLOW/ ORANGE/ RED/ 

BLACK BLACK BLACK BLACK 

Table 5: Colour Coding for Deck Bundles 

Lifting and Storage 

The customer should arrange for bundles to be lifted using two 

double wrapped chains, with care taken to avoid excessive pressure 

across the sheets. Careless use of the slings can cause panels to 

buckle. Under no circumstances should the bundles or sheets be 

removed from delivery vehicles by tipping, barring or similar means. 

Bundles should be lifted directly from the delivery vehicle and placed 

on the building framework at the correct level and in positions 

appropriate for installation. Generally one bundle of decking will 

be positioned in each steelwork bay. The sides of the bundles are 

identified with paint splashes and these marked sides must all face 

the appropriate set out point. Care must be taken to avoid local 

overloading of the structure.

Fixing and Securing 

Prior to the commencement of installation of the decking the 

supporting structure must be in a sound and stable condition. 

Steelwork must be adequately restrained and support for the decking 

must be provided around columns, splices, openings and other 

penetrations. Brickwork, blockwork and concrete supports must be 

adequately cured. 

Steelwork Concrete Other Materials 

(incl. Brick and Block) 

50mm 70mm 70mm 

Table 6: Minimum Bearing Requirements for Decking 

Decking MUST be suitably secured to avoid excessive deflection 

or dislodgement during construction. The fixings should be placed 

at 333mm maximum spacing at panel ends and 667mm maximum 

spacing on intermediate supports. No pedestrian access to the 

installed decking should be permitted until it has been securely fixed 

to the supporting structure and access is recommended to be limited 

to essential construction personnel once installation is complete. 

In the case of a steel support structure, low power powder-actuated 

fastenings such as Hilti ENP 2 can be used with the DX 750 cartridge 

tool to make this connection. In situations where shear studs are 

subsequently to be welded through the decking, a lighter gauge nail 

such as Hilti DAK 16 can be used with the DX A40 or A41 cartridge 

tools at the discretion of the Project Structural Design Engineer. 

Alternatives to Hilti nails are available through companies such as 

Spit, or decking can be secured to steelwork using self-tapping 

screws. Decking may be secured to brickwork, blockwork and 

concrete supports provided that the top surface is flat and level and 

that the top course of bricks or blocks are of solid construction. 

Special masonry fixings, such as the Hilti HPS-1 Hammer Screw 

and Hilti X-SW Soft Washer Fastener can be considered, but in all 

instances it is recommended that the decking installer refers to the 

fixing manufacturer’s recommendations for the system to be used. 

Decking may be cut on site to accommodate notching around 

obstructions such as columns but this may affect the design of 

the sheet and its spanning capability. In such situations special 

consideration should be given as to the adequacy and completeness 

of bearings and to the spanning capability of cut sheets, adjacent 

sheets and the finished floor slab. A petrol-driven disc cutter is the 

preferred method for cutting deck sheets and edge trim on site. 

It is recommended that all profiles in the Ribdeck range be seamstitched 

at regular intervals along their length using self-tapping 

screws. Care should be taken to ensure that the seam stitch screws 

effectively penetrate and engage with the under-lapping deck sheet. 

Ribdeck E60 Ribdeck 80 Ribdeck AL 

1.0 m 1.5 m 1.0 m 

Table 7: Max imum Spacing of Seam Stitch Screws 

Note: The guidance given here applies to the shallow deck range of 

profiles supplied by RLSD. Separate guidance should be sought on 

the safe installation of deep deck profile CF225. 

Cartridge Tools 

Hilti cartridge tools are commonly used to install ENP 2 and DAK 

16 nails. No external power source is required. These tools should 

be used only by suitably-trained personnel in accordance with 

manufacturer’s instructions. When detailing steelwork for the 

support of metal decking sheets, consideration should be given to 

the physical dimensions of the cartridge tool, which must be held 

perpendicular to the fixing surface and will experience a re-coil effect 

on firing. 

The nails are suitable for 

fastening decking and edge 

trim to structural steelwork 

up to 630 R N/mm m 2 and a 

minimum thickness of 6mm. 

Technical advice on the 

use of these tools can be 

obtained from Hilti Technical 

Advisory Service, Manchester 

(Freephone 0800 886 100, 

e-mail gbsales@hilti.com, 

web www.hilti.com). 

Alternative tools and fixings 

can be obtained from Spit 

(tel: 0141 764 2700, e-mail 

support@itwspit.co.uk, web 

www.itwspit.co.uk). 

Site Testing 

Once nails have been installed, the effectiveness of the fixing can 

be determined by comparing appearance of the installed nail 

with guidance diagrams and other information in the 

manufacturer’s literature. 

Edge Trim 

Galvanised steel edge trim is not a structural component. It is used 

only as permanent formwork to retain the wet concrete slabs, 

avoiding the need for timber shuttering. It is normally supplied in 

3m lengths but may be in 2.5m lengths if obtained directly from our 

stock depots. Thicknesses, or gauges, are usually 1.0mm or 1.2mm, 

but can be up to 2mm when needed. Edge trim is supplied complete 

with restraint strapping in standard 1.2m lengths to be cut to suit 

on site. Fixing screws are only provided when RLSD is carrying out 

installation. 

Edge trim can be secured to the end of a decking sheet using selftapping 

screws (see detail 1) or to the main support structure using 

the same fixings as used for securing the decking (details 2 & 3). 

Fixings to the top flange are normally made at each end of the edge 

trim sheet and at no more than 600mm centres along its length. 

Edge trim is delivered to 

site in straight lengths 

and is cut to suit on 

site. To approximate a 

curve, the edge trim can 

be cut on site to form 

a facetted face and the 

frequency of fixings may 

need to be increased 

accordingly. 

Restraint straps are used 

to control the outward 

deflection of the edge 

trim under pressure 

from the wet concrete 

and should generally be 

installed at no more than 

600mm centres and at 

an angle no steeper than 

45o . Restraint straps will 

normally be provided in 

1.0 mm gauge but this 

may be increased where 

additional rigidity is 

demanded. 

WARninG: Steel decking is a structural element of the 

construction and should always be installed by a competent 

contractor to avoid adverse effects on following trades. As a 

minimum requirement, valid CSCS cards for steel decking and/ 

or stud welding should be held by all workers involved in the 

installation of these products. 

41

42 

Cantilevered Deck and Trim 

Special consideration should be given to cantilevers. Guidance is 

given here on the use of both decking and edge trim as cantilevered 

shuttering. It is the responsibility of the Project Structural Design 

Engineer to assess whether any additional reinforcement is required 

to enable the finished floor slab to carry the design imposed loads. 

In the direction of span of the decking sheets, a maximum cantilever 

distance of 600mm is recommended. This limit is based on health & 

safety considerations and is not affected by the gauge or profile of 

decking, or the depth of concrete to be poured. It is important that 

the back span of the decking sheet is securely anchored at no more 

than the recommended maximum spacing for end and intermediate 

supports respectively. Unsupported side cantilevers of decking are 

NOT permitted in any circumstances. 

Edge trim cantilevers are measured from the toe of the beam flange. 

The maximum cantilever length permitted varies with concrete depth 

to be poured and with gauge of edge trim. When cantilevering edge 

trim to the distances shown in Table 8, the maximum spacing of the 

restraint straps and fixings to the beam top flange should follow the 

guidelines given previously for non-cantilevered edge trim. 

Overall Deck End Deck Side Edge Trim 

Slab From Beam Centreline From Toe of Beam 

Depth Any Gauge 1.0 1.2 2.0 

130 600 0 105 120 180 

150 600 0 100 115 175 

175 600 0 n/a 110 165 

200 600 0 n/a 105 160 

250 600 0 n/a n/a 150 

Table 8: Maximum Cantilever Distances 

For conditions outside of the scope of Table 8, permanent supports 

or temporary propping may be required. Please refer to the RLSD 

Technical Department for further guidance. 

Decking on Shelf Angles 

Where decking is required to be supported on shelf angles, the 

following checks are made to ensure it is physically possible to place 

panels of sufficient length to achieve 50mm minimum end bearings. 

Similar arrangements are necessary where the decking panels sit on 

the bottom flanges of steelwork. 

lm i n = lc l e a r + 2 x 50mm 

lm a x = lc c –B / 2 - Tw / 2 - 20mm [- Tr s a if angle leg upwards] 

Where: 

lm i n is the minimum allowable sheet length 

lm a x is the maximum allowable sheet length 

lc l e a r is the clear distance between toes of shelf angles 

lc c is the centre to centre spacing of the beams 

B is the smaller of the two flange widths 

Tw is the web thickness of the other beam 

T r s a is the thickness of the vertical leg of the shelf angle 

T w 

B 

The shelf angles are structural supports and the Project Structural 

Design Engineer should ensure that they are fit for purpose. In 

addition it is important that the angles project a minimum of 50 mm 

beyond the top flange of the steel beam to enable a cartridge tool or 

similar to be used to secure the decking to the supporting structure. 

www.rlsd.com 

L c c 

L c l e a r 

T r s a 

Decking Around Columns 

Decking should be cut on site to fit into the webs of columns that 

penetrate the floor plate. Where there are no beams available as 

supports, and where column penetrations exceed 250mm in width, 

the steel frame supplier should provide additional support (such as 

welded on angle brackets) in the web of the column. 

Decking Support Details at a Column Web 

Minimising Concrete Loss 

Wherever possible, decking sheets are butt jointed with ribs 

lined through. Gaps up to 5mm in width can be tolerated without 

significant leakage of concrete over the top flange of the beams. 

Gaps greater than 5mm should be sealed using a method such as 

adhesive tape or expanding foam. At the building perimeter the 

decking should either continue out to butt up against the edge trim 

or be sealed using a 0.7mm gauge galvanised steel closure plate or 

preformed polystyrene inserts. 

For the treatment of side 

lap joints of decking refer to 

the earlier section on seam 

stitching requirements. 

Where the decking changes 

direction of span it may 

be necessary to stitch the 

edge of the last sheet to 

the supporting beam and 

seal off the ends of the 

perpendicularly-spanning sheets with closure plates or preformed 

polystyrene inserts. 

Concrete Encased Perimeter Steel Beams 

Concrete encasement may be specified as part of the fire resistant 

design of perimeter steel members. The preferred method of 

construction is for concrete encasement to be carried out off site 

prior to erection of the steel frame. If the encasement only extends 

to the top of the steel beam, then metal decking installation can 

proceed as normal. 

In situations where pre-encasement is not practical, the following 

solution is offered for Holorib floor slabs only. The Holorib decking 

should be fitted to the perimeter steel beams as normal to provide a 

working platform and then cut back to the line of the shuttering once 

it has been installed around the beam. The Project Structural Design 

Engineer should check that the shuttering system has been designed 

to support the decking and subsequent weight of wet concrete, and 

if not, to specify the inclusion of an adequate temporary propping 

system as indicated in the diagram. 

A sufficient quantity of hairpin tie bars, as determined by the Project 

Structural Design Engineer, should be positioned in each trough of 

the Holorib decking prior to placement of the concrete.

SHEAR STUDS 

Shear studs are normally welded through the decking to the top 

flange of the steel beam. To avoid burn through of the beam 

flange the studs should be welded directly above the web (on the 

beam centreline) or the flange should have a minimum thickness 

of 0.4 times the shank diameter (0.4 d = 7.6mm generally). It is 

preferable to limit the number of studs to a maximum of 2 per 

trough, wherever possible. As the number of studs increases beyond 

this limit, the decking becomes more susceptible to localised heat 

warping and weld splatter can interfere with subsequent welds. 

An alternative to welded shear studs is the Hilti HVB shear 

connector. These connectors are ‘L’ shaped galvanised steel 

sections that are secured to the steel beam flange using the Hilti 

DX750 powder actuated tool. The mechanical properties of the HVB 

connectors are different to those of welded studs and a substitution 

should not be made without the consent of the Project Structural 

Design Engineer. 

A greater number of HVB connectors are needed to provide the 

same degree of shear connection as when using welded studs, and 

particular attention should be paid to the space available for placing 

these within the confines of a steel decking profile. Guidance and 

assistance on the application of the HVB system is available from 

Hilti (tel: 0800 886100). 

Spacing of Shear Studs 

In order to maintain effective shear connection, both maximum 

and minimum spacings are defined for the studs. The maximum 

longitudinal spacing is defined to prevent localised vertical separation 

of the slab from the beam. Minimum spacings are defined to 

ensure that each stud is adequately embedded in concrete and that 

concentrations of compressive force do not occur as a result of 

overlapping zones of influence around adjacent studs. 

The studs should not be welded closer than 20mm 

clear distance from the edge of the top flange 

Preparation of Steel Flanges 

Any impurities present at the welding interface will lead to a 

decrease in weld quality. RLSD profiles are formed from steel with a 

Z275 galvanised coating and the through deck welding process can 

be successfully applied to this material provided that the top flange 

of the steel beam is not primed, painted or galvanised and is also 

free from dirt, grease and loose rust. Light rusting that occurs after 

shot blasting is acceptable. In the welding zone, the decking should 

fit closely against the beam top flange, a condition that can generally 

be assured by the installer at the time of welding. 

Stud Installation Equipment 

The preferred method for welding shear studs is through the use 

of mains power. This provides a quiet, clean and environmentallyfriendly 

option. The supply should be 3 phase with 415 V / 150 A per 

phase. The welding convertor, measuring 0.5m cubed and weighing 

0.5 tonne, is connected to this supply through a watertight 150 amp 

plug and socket. 

Where RLSD is carrying out installation using a chassis mounted 

mobile generator unit, access to within 7.5m of the structural 

steel frame will be required. This unit consists of a 200 KVA diesel 

generator and welding convertor housed in the rear of a vehicle 

which is 7m long, 2.6m wide and 3.5m high. From this position stud 

welding can be carried out at a radius of up to 80m. 

Where access for the welding rig to within 7.5m of the frame is 

restricted, a steel section may be welded to the frame and extended 

to a position from which the 7.5m access rule may be applied. 

This steel section should, as a minimum, be a steel plate 

measuring 100 x 10mm. 

In situations where access for the mobile rig is restricted and mains 

power is not available, a static generator can be provided. This 200 

KVA generator is housed in a unit measuring 3m long, 2m wide and 

2m high and with a gross weight of 5 tonnes. This unit will emit 

diesel fumes when in operation and should be positioned on the 

structure in a well-ventilated area which is verified as suitable for this 

purpose by the Project Structural Design Engineer. Consideration 

should also be given to the method of safely re-fuelling the unit and 

to the safe storage of fuel in a bunded diesel bowser on the site. 

Installation and Testing 

Welded shear studs should be installed and tested in accordance 

with BS5950:Part 3:Section 3.1, the recommendations of the 

manufacturers of the welding equipment and studs, and the project 

specific design and layout. On projects where RLSD have installed 

the studs, any testing in addition to this should be carried out prior 

to the demobilisation of personnel and equipment to avoid any 

additional charges for return visits. 

43

44 

PRIOR TO PLACEMENT OF CONCRETE 

Forming Openings 

The following guidelines are offered for forming openings in a slab. 

It is the responsibility of the Project Structural Design Engineer to 

ensure the slab will be adequate to support the design imposed loads 

after the formation of any openings. RLSD’s responsibilities exclude 

the design, supply or installation of any framing or reinforcement and 

the boxing out of decking to form openings. 

Openings can be classified in terms of the width measured 

perpendicular to the span of the decking: 

1) Up to 250mm wide – No special treatment is required. 

The opening should be boxed out and the decking only cut out 

using a reciprocating saw or nibbler when the slab has cured. 

2) Between 250mm and 700mm wide – The opening should be 

formed as above but additional reinforcement bars should 

be designed and added as necessary to spread the load 

laterally around the opening, supplement the slab strength 

immediately parallel to the opening, and control crack widths 

at corners. 

3) Over 700mm wide – Structural trimming steel should be 

added to the framing arrangement before the decking is 

installed. 

Health and Safety note: Due consideration should be given to the 

means of providing protection against falls and accidental passage 

through of materials at whatever stage openings are formed in the 

slab. One method that can be used is to provide a temporary cover to 

the opening using unconcreted decking secured to a special edge trim. 

CONCRETE PLACEMENT 

Temporary Props 

Immediately prior to concrete placement, it is recommended that 

checks are made to ensure that temporary propping is installed: 

a) where indicated on RLSD drawings if supplied 

under the contract; 

b) where shown to be required on RLSD standard 

span/load tables; 

c) where indicated on project specific design calculations. 

Care should be taken not to over-jack these props whilst ensuring 

that the prop header is in continuous and level contact with the deck 

soffit. The propping system should extend to the full width of the bay 

and be left in place for a minimum of 14 days after the concrete has 

been placed to ensure that sufficient shear bond resistance 

is developed. 

Construction Joints 

Continuous concrete pours in excess of 1,000m 2 can be achieved 

on composite floor slabs. If the limits of the pour do not coincide 

with permanent slab edges, a construction joint should be formed. 

The construction joint should wherever possible be positioned 

over permanent supports at the ends of decking panels, not over 

intermediate supports which would result in only one span of a 

multiple span sheet receiving concrete. 

Where it is not possible to have the construction joint at a sheet end, 

it should be positioned such that no more than 1/3 of the final span 

is left unconcreted. 

www.rlsd.com 

Deck Over Void 

The three size categories, outlined here, relate to isolated openings. 

If openings are grouped such that a gap of less than 1.5 times 

the width of the largest opening exists between them, then 

consideration should be given to the combined width. 

Cleaning the Decking 

It is recommended that any debris on the decking be removed by the 

contractor after all reinforcement has been positioned and openings 

boxed out and immediately prior to concreting. Slight surface grease 

or oil residue from the decking manufacturing process does not 

affect the design bond strength between decking and concrete 

and therefore need not be removed. Any residual ceramic ferrule 

fragments left over after breaking them away from the welded shear 

studs can be left distributed over the decking surface and lost within 

the concrete pour. 

Placing and Compacting 

Care should be taken when concreting in extremes of temperature. 

If the air temperature falls below 4oC, then the concrete should be 

discharged from the mixer at a temperature of no lower than 10oC and be protected from frost and maintained at no lower than 5oC for 

72 hours after placement. In hot weather the concrete temperature 

when deposited should not exceed 32oC and measures should 

be taken to prevent drying out of the surface before any curing 

protection can be applied. 

Where possible the concrete should be pumped or discharged 

from a skip in a controlled manner over an intermediate beam of 

a multiple span sheet and spread evenly into the adjacent spans. 

For single span slabs and in situations where the concrete must be 

discharged directly on to the span, care should be taken not to allow 

the concrete to fall from a height exceeding 1.0m nor for heaping to 

a depth significantly in excess of the design slab depth. Work should 

progress transversely across each bay in a direction such that the lap 

joints are approached from the side of the overlapping sheet. 

If the workability of the concrete is too low, then it will not be 

possible to achieve full compaction and an acceptable finish. 

Advice should be obtained from the concrete supplier on any 

measures to be taken to recover the workability of the mix. Under no 

circumstances should water be added to the concrete after it has left 

the batching plant. 

The concrete should be compacted using a power driven beam or 

plate vibrator. Immersion vibrators should not be used. Care should 

be taken to avoid over-vibration as this could cause segregation of 

the mix, leakage through deck joints, and surface laitance. 

Curing 

Concrete should be protected from the harmful effects of sun, wind, 

cold and rain during the first stage of hardening. The protection 

should be applied as soon as possible after placing the concrete and 

be designed to prevent surface drying for a minimum of 7 days. 

No concrete should be disturbed for at least 24 hours after placing.

COMPOSITE FLOOR SLAB 

Loading of the composite floor slab to its full design load should only 

take place once the concrete has reached its target strength. Early 

loading of the slab can have detrimental effects on the long-term 

strength and load-bearing capacity of the structure. The use of the 

floor slab for storage of materials or as a working platform for further 

erection of the structure should only be attempted with the prior 

approval of the Project Structural Design Engineer. 

Soffit Fixings 

The Holorib and Ribdeck ranges of steel decking allow the 

suspension of lightweight services and fixtures from removable 

wedge-shaped fixings. It is important that the correct wedge fixing 

and decking are paired together and that the wedges are not 

inserted into lap joints. Table 9 shows the options available, together 

with the safe static working load that can be suspended from each 

fixing when attached to a fully cured composite floor slab. 

Profile Wedge Type Thread Size Safe Static 

(mm) Working Load (kg) 

Holorib Holowedge 4 150 

6, 8, 10 200 

Ribdeck E60 Alphawedge 6, 8, 10 100 

Uni-Deck BN1Z 6, 8, 10 150 

Ribdeck 80 Ribwedge R80 6 100 

Alphawedge 6, 8, 10 100 

Uni-Deck BN1Z 6, 8, 10 150 

Ribdeck AL Alphawedge 6, 8, 10 100 

Uni-Deck BN1Z 6, 8, 10 150 

Table 9: Safe Static Working Loads 

Holowedge and Ribwedge R80 

The Holowedge and Ribwedge R80 suspension fixings are available 

from RLSD. They are supplied for use with all gauges of decking 

and are formed in mild steel grade EN1A, electrolytic zinc plated and 

bright passivated to BS EN 12329/12330. To help identify that the 

Holowedges and Ribwedge R80s have been supplied by RLSD and 

are the correct size and shape to carry the loads indicated in Table 9, 

they are uniquely embossed as illustrated. 

Holowedges 

Ribwedges 

The wedges are designed to act as vertical anchors only and should 

not be used as nuts. To avoid local overloading of the floor slab 

the wedges should not be closely grouped, a nominal 600 mm 

grid being recommended as a minimum. Design advice for closer 

groupings should be obtained from the project structural design 

engineer or from RLSD Technical Department. Dynamic loads should 

NOT be supported by wedge fixings. Proprietary anchors can be 

embedded in the slab and used as directed by the manufacturer and 

where approved by the Project Structural Design Engineer. 

Installation Procedure: 

1) Ensure that the correct wedge is selected. 

2) Thread wedge onto the required bolt or rod. 

3) Insert wedge in to dovetail rib from below and rotate 

through 90o so that the sloped faces of the wedge bear on 

the decking ribs. 

4) The bolt or rod should then be finger tightened up to the 

roof of the dovetail or to a washer set against the soffit of 

the decking. 

5) Use mechanical tightening to finish. 

Alphawedge 

The Alphawedge suspension fixing is available from Lindapter 

International Ltd (tel: 01274 521444). It is designed for use with 

all gauges of Ribdeck E60, Ribdeck 80 and Ribdeck AL. Guidance 

on the use of Alphawedge fixings is available from Lindapter 

International Ltd. 

45

Deckspan Design Software 

for Holorib, Ribdeck E60, Ribdeck AL and Ribdeck 80 

available to download free of charge at www.rlsd.com 

46 www.rlsd.com

Our partners... 

Carthusian Court, 12 Carthusian Street, 

London EC1M 6EZ 

Tel: +44 (0) 20 7397 8128 www.faset.org.uk 

Supplied by RAM International 

Tel: +44 (0) 141 353 5168. 

www.ramint.co.uk 

Supplied by CSC (UK) Ltd. 

Tel: +44 (0) 113 239 3000 www.cscworld.com 

Supplied by Oasys Ltd 

Tel: +44 (0) 191 238 7559 www.oasys-software.com 

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Tel: +44 (0) 20 7839 8566 

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Tel +44 (0)1753 692929 Fax +44 (0)1753 691623 

www.graceconstruction.com 

ADVA and STRUX are registered trademarks of W.R. Grace & Co.-Conn. 

47

Richard Lees Steel Decking Ltd 

Moor Farm Road West, The Airfield, Ashbourne, 

Derbyshire, DE6 1HD, UK. 

Tel: +44 (0) 1335 300 999 Fax: +44 (0) 1335 300 888 

www.rlsd.com Email: rlsd.decks@skanska.co.uk 

Content copyright Richard Lees Steel Decking Ltd and liable to change without notice. 

Trademarks acknowledged. 

TM1

Technical Manual - Rlsd

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