Structural Floor Panels Design Guide - Hebel Supercrete AAC ...

More documents

Recommendations

Info

Worked Example Calculation 2.2.5 Calculation Example 2.2.5.1 Description of Example Building For this example, a 15 x 9 metre rectangular two storey structure has been considered with the following construction and location details: in a high wind zone and seismic zone A. The building is constructed from 200mm Supercrete Block for the exterior walls and 200mm and 150mm Supercrete Block for the interior walls and the roof is classed as heavy construction (i.e. concrete tile). Wall height of both lower and upper levels is 2.6 m. and apex height of roof gable is 2.0 m. above the top of walls. Wind Zone High Seismic Zone A Exterior Walls 200mm Supercrete Block Interior Walls 150mm Supercrete Bock (200mm Supercrete Block as required for Roof structure floor panel joins) Floor wall connection Heavy – concrete (ring tile tie) Upper floor Supercrete Structural Floor Panels Floor dead load 0.5 kPa (suspended ceiling) Floor live load 1.5 kPa Floor covering Flexible (L/250 deflection) Fire rating Nil (therefore use 90 minute minimum) 2.2.5.2 Determine the Panel Layout When determining panels, a minimum end seating of 70mm should be allowed, with a side seating of 50mm. Therefore, using the diagram below, the maximum panel span is 4800 minus 2 x 70mm = 4660mm for the panels in the largest diaphragm (D1). 2.2.5.3 Determine the Live and Dead Loads on the Floor Using AS/NZS 1170 Table 3.4.1 for a domestic structure, the floor live load shall be 1.5 kPa uniformly spread or 1.8 kN concentrated. Where using floor panels for balconies, a higher loading of 2 kPa is required. Also, note that for commercial uses, floor loadings are much higher, and the values given in Table 3.4.1 are the minimum that should be considered. Actual calculation of live loads from known loads that will be on the floor may give higher values. Internal Supercrete Block walls on the upper storey Load is transfered by the require direct support slab to the under shear the wall floor panels so that their mass does not influence the dead load. Non load bearing light framed partitions are allowed for in the structural design of the panels by the manufacturer, but these must be truly non load bearing, with no possibility of long term deflection of roof structures able to load the partitions. Load bearing light partitions must also have direct support from below. Generally the dead load used to determine panel thickness is derived from either a suspended ceiling under the panels, or a topping screed on top to encase under floor heating pipes (a 40mm topping slab will give an unfactored dead load contribution of 1.0 kPa on its own). 2.2.5.4 Determine the Floor Panel Thickness Using the load/span Table for flexible floor coverings on page 17 with 1.5 kPa Live Load and 0.5 kPa Dead Load Shear wall gives a required Lateral panel load thickness of 200mm, for 90 minute fire rating, for a span of 4.66 metres, as the maximum span of the next thickness down (175mm panel) is only 4.28 metres. D1 D2 4660 clear span 4800 panel length 15000 2.2.5.5 Determine the Horizontal Loads on the Floor Diaphragm In Supercrete structures, it is normally (but not always) the seismic load that will govern the diaphragm loads, due to the higher proportional mass of the structure compared with a timber structure. Steel beam support to suit wall layout 4160 clear span 4300 panel length SFP 2012 40 Copyright © Supercrete Limited 2008 D3 D4 Supercrete block wall support 4340 4340 9000 Floor slab diaphragm Shear forc Diagonal Accumula bottom st Foundatio
2.2.5.6 Wind Load The wind load on the structure can either be derived using AS/NZS 1170, or the information in Section 5.3 of NZS 3604 (Bracing Design). Even though this Standard is for Horizontal applied loads parallel to panel axis = w kN/m timber structures not requiring specific design, the data used to determine the wind loads applied to the exterior of a structure are universal and independent of the internal materials and construction of the building. NZS 3604 wind analysis is usually adequate for most standard domestic designs. If the structure has an unusual location, or an envelope shape or special feature that requires additional detailed analysis use Part 5 of AS/NZS 1170 Reaction to establish specific wind load. L force in bracing wall The wind zone is derived from factors relating to foundation to topography, exposure, ground roughness, and the wind Bending region detailed in Section 5.2 of NZS 3604. moment For the diagram purpose of this example, the building is deemed to be M max. = wL located in a High Wind Zone which equates to a wind speed of 44 m/s. The wind load acting on the floor diaphragm is generated from the total contributory area of wall that the wind acts on. This includes both pressure and suction wind loads, which must be added together n panels for the load on the floor diaphragm. For the sake of simplicity, the bending capacity of the Supercrete Block walls perpendicular to the wind direction is ignored – this is a conservative approach. The method in which the force resisting system of the structure Panel Axis works, is for the gable end loads to be transferred into the side walls via the diaphragm action and bracing in the roof plane. This load, plus the end wall loads, is transferred to the first floor level via the upper level bracing walls. There is also an additional load at this level from the contributory area of end wall below the floor diaphragm. This total force on the floor diaphragm is therefore calculated as follows: 2 8 8n Max. panel shear force = wS 2n Bending moment diagram for single panel S Reaction force in bracing wall to foundation M max. = wS 2 S Horizontal applied loads perpendicular to panel axis w / m End Elevation Gable end where Pn = ∑ (Pe pressure+ Pe suction) First floor end wall Ground floor wall contribution Total F = = Pn x 9 x 4.67 = 40.2 Pn Ceiling Floor Diaphragm Demand F First Floor Ground Floor Wind Load Pe (kPa) +ve pressure Copyright © Supercrete Limited 2008 2600 2600 2000 F = (Pn x 9) x 2.0 2 F = (Pn x 9) x 2.6 F = (Pn x 9) x 2.6 3 Ceiling First Floor Ground Floor Structure Elevation with applied wind loads. 41 Side Elevation F = Pn x 15 x 2.6 x 1.33 = 51.9 Pn (i.e. > 40.2 Pn) And Pn = Cpn x q where Cpn = net pressure coefficient from pressure and suction combined q = design wind pressure From NZS 3604 5.5.1 q = 0.6 x Vd 2 x 10-3 kPa = 0.6 x 44 x 10-3 = 1.16 kPa 3 Pressure coefficients for end of gable roof structure: Cpe = +0.7 on windward 1wall Table 5.6.2(a) Cpe = - 0.33 on leeward wall Table 5.6.2(b) 2 (by linear interpolation) Total Cpe =+0.7 – (-0.33) = +1.03 Total Pn = 1.03 x 1.16 = 1.2 kPa Total F = 51.9x 1.2 = 62.2 kN This load is assumed to be spread uniformly across the floor area encompassing D1, D2, D3 and D4, so the actual load on each diaphragm is simply proportioned by area. 2.2.5.7 Earthquake Loads Because of its lower strength, Supercrete Block walls are often envisaged as not being suitable for seismic areas. However, because it is solid without cores, it has the same properties in all directions, which is a distinct advantage for earthquake loads, as earthquake loads can apply forces to a structure from any direction. The seismic loadings are determined from a number of factors resulting from the structure type, material and size. These are used to calculate the bracing demand values, given in the NZ Addendum to the Technical Manual for Supercrete Block Construction (January 2006). For this example structure with a heavy roof in Seismic 100 mm Zone A, the seismic demand is for 28 Bu/m2100 mm of floor area. This equates to a total seismic force at this 0.6D level of : F1 = 28 x15 x 9 = 189 kN 20* *Note: 20 Bracing unit = 1 KN of Shear Force Note that this load does not have to be factored for analysis as a building part as defined in AS/NZS 1170 Section 4.12.1 as this has already been taken into account in the above table. 15000 Total Wind Load per metre of building width =7.2 x Pe Wind Load Pe (kPa) -ve suction SFP 2012 D Worked Example Calculation
Page 1 and 2: Structural Floor Panels Design Guid
Page 3 and 4: Contents 1.0 System Overview 1.1 In
Page 5 and 6: 1.0 System Overview 1.1 Introductio
Page 7 and 8: 1.1.3 Material Characteristics Work
Page 9 and 10: Airborne noise is effectively block
Page 11 and 12: Table 3. Directly Glued Vinyl Sheet
Page 13 and 14: Table 7. 20mm timber T&G plank floo
Page 15 and 16: 1.5 Other System Features and Benef
Page 17 and 18: Table 9. Span Chart - Max. Clear Sp
Page 19 and 20: Structural Floor Panel floor step d
Page 21 and 22: Full width panel openings Detail No
Page 23 and 24: Selected Supercoat Coating System 1
Page 25 and 26: A ‘Below Plane Beam’ has the pa
Page 27 and 28: In-Plane Steel Beam Support Detail
Page 29 and 30: 2.1.6.7 Panel Connection to Interme
Page 31 and 32: 2.2 Bracing Design 2.2.1 Floor Brac
Page 33 and 34: 2.2.2 Supercrete Structural Floor P
Page 35 and 36: Varies 200, 250, or 300 mm TYPE 2 2
Page 37 and 38: lied loads parallel to panel axis =
Page 39: 2.2.4.5 Flow Chart for Floor Diaphr
Page 43 and 44: Panels arrive on site, strapped in
Page 45 and 46: 3.2.3 Personnel Required Pallet Cre
Page 47 and 48: 4.0 Surface Treatments The installa
Page 49 and 50: 4.2.8 Tiles Supercrete Structural F
Page 51 and 52: Appendix A Custom Floor Panel Reque

Structural Floor Panels Design Guide - Hebel Supercrete AAC ...

Create successful ePaper yourself

Delete template?

Save as template?