Two-Way Spanning Slab Design
BS 8110-1:1997 · Cl. 3.5.31
Slab Dimensions & Material Properties
Cl. 3.5.1m
m
mm
mm
mm
mm
N/mm²
N/mm²
kN/m³
2
Boundary Conditions
Table 3.13 / 3.14Hatched edge = continuous · Plain edge = discontinuous
3
Loading
Cl. 2.4.3kN/m²
kN/m²
| Item | Formula | Value |
|---|---|---|
| Self-weight of slab | h × ρ | — |
| Total dead load, Gk | self-weight + partitions/finishes | — |
| Design ultimate load, n | γf,G·Gk + γf,Q·Qk | — |
4
Bending Moment Coefficients & Ultimate Moments
Msx=βsx·n·Lx² · Msy=βsy·n·Lx²| Location | Coefficient β | Formula | Ultimate moment Mu |
|---|
Coefficients are linearly interpolated from BS 8110-1:1997 Table 3.14 at the current Ly/Lx ratio. Hogging coefficients apply only where the corresponding edge is continuous; discontinuous edges carry nominal top steel only (no calculated hogging moment).
5
Reinforcement Design
Cl. 3.4.4.4 · b = 1000 mm stripShort span (Lx direction) — dx = — mm
Long span (Ly direction) — dy = — mm
6
Deflection Check
Cl. 3.4.6 · Table 3.9 / 3.107
Design Summary & Checks
Final outputReinforcement summary
Design checks
This tool implements the standard BS 8110-1:1997 restrained-slab moment-coefficient method (Table 3.13/3.14) for engineering guidance. Independently verify moment coefficients, member sizing and detailing against your own copy of BS 8110-1:1997 before use in a final design submission.