Structure material - Engineering Class Home Pages

Structure 

material 

Wood 

Steel 

Concrete 

Masonry 

Fabric 

Material Copyright Prof Schierle 2011 1 

Rupture Length 

Rupture length is the maximum length a bar of 

constant cross section can be suspended without 

rupture under it’s weight in tension (compression 

for concrete & masonry) 

Rapture length defines the efficiency of material as 

ratio strength / weight: 

R = F / � 

where 

R = rupture length 

F = breaking strength 

� = specific gravity (self weight) 

The graph is partly based on a study of the 

Light weight Structures Institute Stuttgart University 


Wood 

Energy use 

For simple beam of 

• Aluminum [Aluminium] 

• Concrete [Béton] 

• Steel [Acier] 

• Wood [Bois] 

demonstrates wood requires 

much less energy ! �� 

Study of EPFL 

(Ecole Polytechnique Federale de Lausanne) 


1

Wood 

Types: 

• Balloon framing (rare) 

• Platform framing 

• Heavy timber framing 

Advantages: 

• The only renewable material 

• Warm, natural appearance 

• Low energy required 

• Easy to work 

• Low cost 

Challenges: 

• Combustible 

• Termite attacks 

• Decays in variable humidity 

• Limited height and floor area 


Platform framing 

Platform framing is used for low-rise residential 

structures, due to economy & flexibility. 2x4 studs 

@ 16” reach from platform to platform. Double 

top plates overlap at corners and splices. Plywood 

sheathing, nailed to studs, resists lateral wind and 

seismic loads. Joists, usually 2x12 @ 16” support 

plywood floor and roof (platforms). Blocking 

resists joist buckling and supports plywood panel 

edges to transfer shear. Standard plywood and 

gypsum board panels 48” (4’) wide match 2, 3, or 4 

joist/stud spaces of 24”, 16” or 12”, respectively. 

A Joists, 2x12 or 2x10 @ 16", 24“, or 12” o.c.. 

B Blocking 

C Double top plates overlap at corners and splices 

D Studs, 2x4, 2x6, or 3x4 @ 16“ or 24” o. c. 

E Bottom plates 

F Double plates supporting joists 

G Anchor bolt, 1/2“ @ 4‘ o. c. 

H Sole plate, min. 6" above soil 

I Concrete foundation 

Maximum height: 3 stories (4 with fire sprinklers) 


Wall erection 

Plywood shear wall resists 

lateral wind and seismic loads 

Woodframe house 


2

Clifton Condos, Beverly Hills 

Architect: Schierle 


Terrace Homes, Hermosa Beach 



Terrace Homes 

Hermosa Beach 


3

Heavy timber framing 


Timber house 

Architect: Thomas Herzog 

(rods resist lateral load) 

Gamble house Pasadena 

Architects: Green and Green 


Compression � �Tension 

- � Strain � + 

Hysteresis loop 

(test stress-strain curve) 

E = Energy absorbed by 

ductility 

Steel 

Types: 

• Heavy steel 

• Light gauge steel 

Advantages: 

• Can be recycled 

• Ductile (absorbs seismic energy) 

• Lighter than concrete and masonry 

(small seismic forces) 

• No limitation of height or floor area 

Challenges: 

• Requires much energy to produce 

• Higher cost than other material 

• Requires fire proofing 

• Requires accurate workmanship 

• Limited availability in some countries 


4

Heavy steel shapes 

Profiles: typical labels 

1. W-shape, light (W14x22) 

2. W-shape, heavy (W14x730) 

3. S-shape, Standard (S12x50) 

4. W-shape, wide flange (W16x40) 

5. C-shape, Channel (C10x30) 

6. T-shape 

Cut from S-shape (ST6x25) 

Cut from W-shape (WT8x20) 

7. Angle, unequal legs (L6x4x½) 

Double angle (DL6x4x½) 

8. Angle, equal legs (L4x4x½) 

Double angle (DL3x3x½) 

9. Pipe 

Standard (P4) 

Extra strong (XP4) 

Double extra strong (DXP4) 

10. Structural Tubing 

Square (ST6x6x½) 

Rectangular (ST8x4x½) 


Floor / roof framing 


Steel joints 

1 Pin joint, transfers only beam shear to column 

2 Classic moment joint, transfers shear and bending moment 

3 Dog-bone moment joint, reduces stress for seismic safety 

4 Joist to beam joint with top flange cut back 

5 Beam to beam joint with both flanges cut back 

A Column 

B Beam 

C Connector angles, welded in shop, bolted in field 

D Machine bolts, usually installed in field to connect beam 

E Welded connection of beam flanges to column 

F Stiffener plates resist bending stress from beam flanges 

G Secondary beam / joist supported by primary beam / girder 


5

Steel moment frames 

Beam / column moment joint 

provides lateral resistance 


Truss floors 

Joist and beam roof 


Expressed steel 

Hillside house 

Architect: Helmut Schulitz 

Braced frame 

Imos factory 

Architect: Richard Rogers 

Cable stayed roof 


6

Light-gauge steel 

(cold-rolled) 

1. Channel stud (2 ½ – 6“) 

2. C-stud (2 ½ – 6“) 

3. I-stud (3 5/8 –8“) 

4. C-joist (6 – 12”) 

5. I-joist (6 – 12”) 


Light-gauge steel 


Concrete 

Types: 

• Site cast 

• Precast 

• Prestressed 

Advantages: 

• Widely available 


• Many finishes 

• Takes any form 

• Fire resistant 

• Durable 

Challenges: 

• Heavy weight 

(large seismic forces) 

• Requires rebars 

to resist tension 

• Possible cracks 

without prestress 


7

Concrete properties: 

• strong in compression 

• weak in tension 

• steel re-bars resist tension 


Site cast concrete 

facilitates free forms but 

formwork may be costly 


Precast Concrete 

Advantages: 

• repetitive use of formwork 

• factory quality control 

Challenges: 

• element joints 

• transportation cost 


8

Precast Concrete 


Masonry 

Types: 

• Brick masonry 

• Concrete masonry 

• Stone masonry 

Historic stone masonry: 

Roman aqueduct Segovia, Spain 

Roman aqueduct Pont du Gard France 

Advantages: 

• Widely available 


• Earthy appearance 

• Fire rated 

• Durable 

Challenges: 

• Heavy weight 

(large seismic forces) 

• Requires rebars to 

resist seismic forces 

• Limited height 


Brick Masonry 

CMU (Concrete Masonry Units) 


9

Modular coordination 

Based on unit size 

A Inside dimensions: # of units + 1 joint 

3 units+4 joints 

B Outside dimensions: # of units – 1 joint 


C System dimensions: # of units 



Concrete masonry 

CMU: Concrete Masonry Units 

Minimum reinforcement 

Rebars around openings 

In severe seismic areas: 

Horizontal & vertical rebars @ 4 feet 

In moderate seismic areas: 

Horizontal rebars @ 10 feet 

Vertical rebars @ 4 feet 


Brick masonry 

Minimum reinforcement 

Rerbars around openings 

In severe seismic areas: 

Horizontal & vertical rebars @ 4 feet 

In moderate seismic areas: 

Horizontal rebars @ 10 feet 

Vertical rebars @ 4 feet 


10

CMU wall with rebars 

Grouting 

(bonds rebars with masonry) 


San Diego Convention Center (anticlastic) 

Architect: Arthur Erickson; Engineer: Horst Berger 

Fabric 

Types: 

• Anticlastic (saddle shape) 

• Air supported 

• Air inflated 

Advantages: 

• Light-weight 

(less seismic load) 

• Translucent 

(daylight saves energy) 

Challenges: 

• Fire rating 

(Teflon coated fiber glass is 

fire rated; polyester is not) 

• Durability (about 30 years) 


Air supported 

Inside air pressure 

greater than outside 

• Require revolving doors 

to keep air pressure 

Air inflated 

Air pressure between 

double membrane or tubes 


11

Anticlastic Membranes 

Stadium roof Oldenburg, Germany 

Engineer: Schlaich / Bergermann 



Architect: Saugey / Schierle 

Engineer: Froadveaux / Weber 

Swiss Expo 64 

Stuttgart 


Engineer: ASI 

Sea World Vallejo 

Stadium roofs 

Engineer: Schlaich / Bergermann 

Kuala Lumpur 


12

Structure 

material 

Use intrinsic beauty 

Wood 

Steel 

Concrete 

Masonry 

Fabric 


13

Structure material - Engineering Class Home Pages

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