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Flat slab: total design moment in a panel

Total design moment of a flat slab panel by the direct design method and its split into negative and positive moments. Reference: IS 456:2000 Cl. 31.4.2.2, 31.4.3.

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Flat slab: total design moment in a panel: worked example sheet in Equation Pad with typeset equations and results.

Example only. This sheet shows one way to set out the check. It is not endorsed by the bodies that publish the design codes and does not reproduce them. Check every clause, value and assumption against your own copy of the current edition of IS 456 before you use it, and have the result checked by a competent person. See the disclaimer.

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# Data
l_1 := 7 m
l_2 := 6 m
c := 0.5 m
w := 1.5*(6 kN/m^2 + 4 kN/m^2) =

# Total moment
l_n := max(l_1 - c, 0.65*l_1) =
W := w*l_2*l_n = kN
M_0 := W*l_n/8 = kN*m

# Interior span
M_neg := 0.65*M_0 = kN*m
M_pos := 0.35*M_0 = kN*m

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