CIVIL ENGINEERING FORMULAS

154 CHAPTER FIVE

Shear unit stress on a horizontal section of a counterfort may be computed
fromvcV 1 /bd, where bis the thickness of the counterfort and dis the hori-
zontal distance from face of wall to main steel,

(5.120)

where Vshear on section
Mbending moment at section
angle earth face of counterfort makes with vertical
angle wall face makes with vertical

For a vertical wall face, 0 and V 1 V(M/d)tan. The critical section
for shear may be taken conservatively at a distance up from the base equal to d
sin cos , where dis the depth of counterfort along the top of the base.

V 1 V

M

d

(tan tan)

Counterfort

AA

Heel

(a) Section B-B

(b) PlanA-A

B

B

Toe

FIGURE 5.6 Counterfort retaining wall. (a) Vertical

section. (b) Horizontal section.