STRUCTURAL DESIGN FOR ARCHITECTURE

Table 2.1 Normal span ranges for commonly used structural systems

A Timber structures

Structural system Normal span range (m) Span/depth ratio

softwood planks floor 0.6-0.8 25-35

roof 2-6 45-60

plywood board floor 0.3-0.9 30-40

roof 0.3-1.2 50-70

softwood timber joist floor 3.5-6 12-20

roof 2-6 20-25

stressed skin timber panel floor 3-6 20-30

roof 3-9 30-35

laminated timber beam floor 5-12 14-18

roof 4-30 15-20

plyweb beam floor 5-18 8-10

roof 6-20 10-15

trussed rafter roof 5-11 4-6

parallel chord truss roof 12-25 8-10

gluelam portal frame roof 12-35 30-50

gluelam arch roof 15-100 30-50

lattice dome roof 15-200 40-50

B Steel structures

Structural system Normal span range (m) Span/depth ratio

profiled decking floor 2-3 35-40

roof 2-6 40-70

profiled decking with composite concrete topping floor 2-6 25-30

beam (hot-rolled section) floor 6-25 15-20

roof 6-60 18-26

cold-formed open-web joist roof 4-30 15-25

hot-rolled triangulated parallel-chord truss floor 12-45 4-12

roof 12-75 10-18

pitched, triangulated truss roof 25-65 5-10

space deck roof 10-150 15-30

braced barrel vault roof 20-100 55-60

portal framework roof 9-60 35-40

cable-stayed roof roof 60-150 5-10

hanging cable roof roof 50-180 8-15

C Reinforced concrete structures

Structural system Normal span range (m) Span/depth ratio

one-way span solid slab reinforced 2-7 22-32

prestressed 5-9 38-45

two-way span solid slab reinforced 4.5-6 30-35

one-way span ribbed slab reinforced 4-11 18-26

prestressed 10-18 30-38

two-way span coffered slab reinforced 6-15 18-25

prestressed 10-22 25-32

beam/column frame with beam/slab floor slab 3.5-6 30-36

beam 6-12 15-20

portal framework 12-24 22-30

arch 15-60 28-40

Structural Design for Architecture

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