SRW Abut Existing Structures

How do you design a modular retaining wall that adjoins an existing structure?

Our Allan Block Engineering Department fields multiple questions everyday from our AB Walls Design Software to design solutions for a project. A common question we have received lately is: How do you design a modular retaining wall that adjoins an existing structure?

Be it a building foundation, an existing concrete wall or even another segmental retaining wall (SRW) there are a few things to consider:

• How are the walls abutting? Perpendicular or in-line?
• The setback/batter of the walls – do they match?
• How will they connect?

An SRW can abut an existing structure perpendicularly on its face with little concern beyond aesthetic but for wall abutting in-line, the concern of how the setback of the wall(s) will align come into consideration.

If the existing structure has no setback its thickness and height are factors that will affect the layout of the SRW. Sometimes the amount of setback could result in exposing the soil behind an existing retaining wall, which will require returns, either at the top or bottom of the SRW, to enclose the exposed soil.

It is not recommended to mechanically connect SRWs to existing structures for many reasons, as listed below.

• SRWs are meant to move with soil movement and if they are connected to a rigid structure, the connection points will be subject to loading that was not designed for, resulting in damage to both structures.
• If the existing structure is another SRW, the block heights and setbacks may not be the same which could lead to issues if the walls are to be weaved together. A solution would be to place a column between the 2 walls for a vertical transition.

If you have a SRW that is to adjoin with an existing structure, give the Allan Block engineering department a call (800-899-5309 x 3) or email engineering@allanblock.com for assistance.