How to Apply Load from Adjacent Building on New Retaining Wall?

[emanyalpsid]

Hello people of eng-tips after a couple years of lurking I finally have a question that I cant find a previous post to help with. I am designing a retaining wall that is deeper than the adjacent footing of the neighboring building. Its not ideal but thats how it goes sometimes. I have been trying to figure out how the loads from the existing structure will be applied to the new retaining wall.

Since loads travel downward in a triangular path, would it make sense to load the wall with an additional active pressure (Im only familiar with EFP for retaining wall design) of (P/2)/D since half of the load will travel to the right away from the new wall? I browsed over some geotechnical textbooks but didnt find any examples of adjacent loading but if anyone has any good sources id be grateful for some info. Thanks

 

[Celt83]

Bowles - Foundation Analysis and Design - 5th Edition

Also search for Boussinesq Equation.

AASHTO adopts a form of the Boussinesq Equation for their adjacent surcharge formulas.

 

[structSU10]

You have to hold that building up during construction. This seems to me to need either underpinning, driven sheeting, or a soldier pile and lagging wall. Depending on what is used you may or may not have pressure from that building exerted on your basement wall.

 

[emanyalpsid]

@structSU10 - theres temporary shoring designed by others so I still need to design for the loads after the shoring is removed

@Celt83 - thanks for the direction, I used boussinesq equation and applied it as a point load and summed all the point loads that would result from a line loading per ft of my wall. And then I noticed Enercalc has an adjacent footing option after all this and the answer from Enercalc is close to what I got so thats good that atleast I know now how its working.

Much appreciated

 

[Celt83]

Just be careful with the Boussinesq equation I recall seeing many discussions in the past about what value should be used for Poisson's ratio ( μ )