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Cantilever slab (chajja)

Moment and steel for a cantilever slab with a point load at the tip, with the deflection ratio check. Reference: IS 456:2000 Cl. 23.2.1, 26.5.2.

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Cantilever slab (chajja): 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 := 1.2 m
D := 200 mm
d := 175 mm
b := 1000 mm
f_ck := 25 MPa
f_y := 415 MPa
w := (25 kN/m^3)*D + 1 kN/m^2 + 2 kN/m^2 =
P := 1 kN/m

# Moment and steel
M_u := 1.5*(w*b*l^2/2 + P*b*l) = kN*m
A_st := 0.5*f_ck/f_y*(1 - sqrt(1 - 4.6*M_u/(f_ck*b*d^2)))*b*d = mm^2
A_st.min := 0.0012*b*D = mm^2

# Deflection
l/d <= 7 =

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