Masonry Allowable Stress Unity Check

\frac{f _{a}}{F _{a}} + \frac{f _{b}}{F _{b}} \leq 1

ASD masonry: axial fa=P/A and bending fb=M/S interact by a unity equation (handbook). Fa includes slenderness; Fb is a fraction of f'm. Inspect special inspection / k-factors as given.

$f a$: Axial compressive stress
$f b$: Bending compressive stress
$F a, F b$: Allowables

Step-by-step solved example

fa=40 psi, Fa=80, fb=90, Fb=200. Unity?

Masonry wall: fa/Fa + fb/Fb ≤ 1 with slenderness in Fa.

1. Ratio
40/80 + 90/200 = 0.50+0.45=0.95.
2. Check
0.95 ≤ 1, OK.

Answer: 0.95 ≤ 1 (OK)

10 practice questions

0/10 correct

1.If unity >1 the wall is

2.f'm is

3.Fa drops as h/t increases because

4.An unreinforced masonry wall has limited

5.40/80+90/180 =

6.Grouted cells plus rebar make the wall

7.Modulus Em is often

8.Out-of-plane wind is typically the source of

9.A pilaster is

10.Allowable Fb is a fraction of f'm (e.g. 1/3) so if f'm doubles, Fb