Cantilever reinforced concrete retaining wall with opening for pipe 1

[Bosco89]

Hello,

When an opening on the stem of a reinforced concrete retaining wall is required for a sewer pipe, what are the changes that should be considered in the design loads when compared to a retaining wall without the opening? Depending on the ratio between the area of the opening and the total area of the stem, do you consider the reduction on the weight of the stem and soil on top of the heel? Do you consider a reduction of active earth pressure along the cross-section with the opening?

Thank you.

 

[BridgeSmith]

For stability (overturning, sliding, soil bearing), I typically don't make any adjustments, since the the inclusion of the pipe typically presents a less critical loading case than without it.

For structural design, I make up for whatever loss of flexural strength occurs at the base of the stem wall, due to interrupted reinforcing, etc., in the adjacent portions of the wall.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[bridgebuster]

Typically for a circular opening, we add four diagonal bars to replace every cut vertical bar. If you have an exceptionally large opening making diagonal bars impractical you could treat the portion of the stem above as a beam or deep shear member.

 

[Bosco89]

Thank you so much!

 

[bridgebuster]

you're welcome