Question

A fully grouted reinforced concrete masonry wall, composed of 8 inch (7.63 in. effective) thick hollow concrete masonry units laid out in full bedding is reinforced with #6 (Ab = 0.44 in2 ) Grade 60 bars (fy = 60,000 psi) at 25 inches on center. Find the wall load capacity for pure compression and pure flexure conditions. The compressive strength of the masonry, f’m, is 2000 psi.

Answer 1

Capacity in pure compression,

P = A​​​​​​wall​​.f'wall + A​​​​​​steel​.f'steel

This calculation should be done for 1 foot width of wall.

Steel in wall is #6 at 25 inch centre to centre distance. Area of steel in 1 foot (12 inch) is = (12/25) x area of one #6 rebar

= (12/25) x 0.44

= 0.2112 sq. Inch

Area of wall = Gross area of wall - area of steel ( All for 1 foot)

= 7.63 x 12 - 0.2112

= 91.3448 sq. Inch

p = 91.3448 x 2000 + 0.2112 x 60000

= 195369.6 pound or 195.37 kips (per foot length of wall)