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[mc.upadhyay1]

IS 13920 says that Effective Depth of wall for shear stress calculation may
be taken as 0.8 time length of wall & flanges are not taken into account
for shear capacity.

Why the example 9 on Design of a shear wall for a two-storey building
(Explanatory Example for Ductile Detailing of RC Buildings Doc No. EQ22-V1)
calculates the effective depth as sum of web depth & flange thickness
(3380+380=3760);
which is more than 0.8*length of the wall (0.8*4140= 3312).

Vertical reinf. is represented by an equivalent steel plate along the
length of
the section as per Annex A of IS 13920 .
I have seen the paper "Seismic behaviour, design and detailing of RC shear
walls Part 1
......... by M.S. Medhekar & S.K. Jain in ICJ July 1993" in which area of
the vertical reinforcement
has been taken as vertical reinf. ratio*area of the considered part of wall
section as if there is steel plate
rather than reinforcement at some spacing.

I want to know whether the limitation of maximum spacing of 450 mm on
vertical reinforcement
as per Cl 9.1.7 is O.K. as per the assumption (of steel plate as vertical
reinforcement) in the
derivation of these equations.

& whether the limitation of maximum spacing of 450 mm on horizontal
(shear) reinforcement
as per Cl 9.1.7 is O.K. as for beams we have maximum spacing of stirrups as
300 mm as per IS 456:2000.
(it was reduced to 300 mm in IS 456:2000 from 450mm in IS 456:1978; don't
know why)

Regards

Mukesh Upadhyay

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