Masonry shear wall - design methodology

[Murali27]

Hi

Can any one suggest on the following steps in masonry shera wall design
I use ACI 530 to design masonry shear wall (In-plane flexure and shear) < Allowable stress design method>

Here the steps what i am following;

1. Calculation of wind loads as per ASCE 7 - 98 with out considering Factor Kd < wind directionality factor>

2. Using the load combinations spelt in ACI 530.

3. The allowable stresses as per ACI 530...

(using the phi factor and 2.5 for arriving design strength)

say allowable shear stress is Fv need to be multipied with 2.5 and phi factor of 0.6 (in shear).. Is it right.

In the context of not using kd factor in wind load calculation, can i increase allowable stresses by one-third

 

[boo1]

1. Allowable shear stresses:
Quantified in terms of M / V d, which is the same thing as h / d since M = V h. Recognize a decrease in wall shear capacity as wall increases in height from a pure shear to a flexural element. Allowable shear stresses are assigned according to whether or not the wall falls into one of two categories:
a. Masonry resists all the shear, and the allowable shear stress takes on one of these values, depending upon M/Vd. In this case, there is no horizontal steel for resisting in-place shear.
b. If the actual wall shear stresses exceed Fv from either (7-19) or (7-20), then the masonry, arbitrarily, is no longer permitted to resist shear. Horizontal steel must be provided to carry the entire shear force. The allowable shear stress is then given by: Shear steel resist all the in-plane shear.

2. Design considerations:
a. In zones 3 and 4, must design shear wall to resist a shear force 1.5 times the force developed from UBC chapter 16 procedures. (UBC 2107.1.7)
b. In zones 3 and 4 (UBC 2106.1.12.4), horizontal steel shall be:
Uniformly distributed over wall height.
smax = smaller of d / 2 or 48&quot;.
Continuously inspected Þ special inspection.
Terminated with standard hook or adequate imbedment.
c. Spacing of horizontal shear steel
d. Not covering shear walls with flange here.

3. In-plane shear is generally the primary stress condition, but must also check: If a single function wall, (e.g. carries only shearforces and no vertical), check wall for bending due to over-turning moment, OTM.
Size jam steel according to Fs = M / As j d. check that fb < Fb
a. If a dual function wall, check wall for bending and compression due to OTM. Size jam steel for tension wall with Fs = M / As j
b. Check that fa / Fa + fb / Fb </= 1