Concrete shear/retaining wall

[nuche1973]

Working on a multistory structure where the foundation wall acts as both a retaining wall and a shear wall. Do I design as a retaing wall first then as a shear wall? or vise versa? How does one approach the combined stresses? Thanks for your assistance.

 

[civilperson]

Design as retaining wall and then check as a shear wall.

 

[DaveAtkins]

The bearing pressure caused by the wall acting as a shear wall should be added or subtracted as appropriate from the bearing pressure caused by the wall acting as a retaining wall.

DaveAtkins

 

[civeng80]

As a first design as a retaining wall.

Then I would tend to agree with DaveAtkins check bearing pressure due to increased pressure from shear wall and increase footing area if necessary.

 

[JAE]

When you say "retaining wall" do you mean it is cantilevered out of the footing and resisting soil pressure? Or does it get support from the footing at bottom and the floor/roof at top?

 

[msquared48]

Although the wall may be both a shear wall and a basement or cantilever wall (non-yielding or yielding), it may be a bearing wall too. I would be more concerned with the capacity of the wall to resist the P + M forces due to a vertical and lateral load combination. Since it is resisting soil, it is fully grouted and probably long with respect to its height. Longitudinal shear is not likely to be a real problem here.

Mike McCann
MMC Engineering

 

[Lion06]

I think he was talking about combined in-plane and out-of-plane loads.

 

[pelotoner]

I agree to design for a retaining wall first and check as a shearwall. Remember that compression will increase the moment capacity of a wall/column up to a point, then the P x e scenario comes into play.

Be careful of the tension end of the shearwall (probably both ends). Depending on the amount of retaining soil and moment, the tension will redestribute the stress blocks, increasing the tension and decreasing the compression. This will increase the steel required on the tension face of the retaining wall.

 

[nuche1973]

The foundation/retaining wall is a restrained wall. Restrained at the top and the bottom by floor slabs.

 

[haynewp]

I would start looking at it like it is a large concrete column with bi-axial bending and shear.

 

[JAE]

haynewp is right in my book.

This is a beam-column situation if it has forces acting perpendicular to its surface. Basically we take a 12" section of the wall and design as for a column.

 

[nuche1973]

Thanks for the information. It is greatly appreciated.