Civil Engineering/Horizontal Pressure from Neighbour footing on Retaining Wall
QUESTION: Dear Sir,
We are planning a basement for one building. there is a existing building in neighbour.
How do I calculate the Horizontal Pressure which will come due to these neighbour foundations on my proposed retaining wall ?
Am Attaching a pic showing the arrangement.
ANSWER: Dear Seyed
You should consider the retaining wall with loaded soil behind it. The general formula is Fh = Ka ( soil weight + Neighbor loading ) . But keep in mind that the distribution pattern of horizontal force due to soil weight is rectangular but the loading one is uniform and rectangular. Take a look at Bowles handbook. Don't hesitate to ask me if you have doubt.
Ka is the active coefficient of earth pressure.
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QUESTION: I do not have the column load of the neigh. foundation.
However i know the SBC is 150 kN/M2
Should i consider this as surcharge load ?? So if Ka is 0.3
The UDL on the retaining wall would be 0.3X150 =45 kn/M ?? Am i correct??
You should investigate the neighbor building and have a clear view of the actual situation. I don't have any idea about the loading , you can get it with in situ investigation. Assume that you found that a pressure of 20 KN/m2 ( be careful about the units) is present under neighbor foundation then you can accept that this loading have a semi infinite nature in area of action.
Then you can accept that the lateral pressure due to this item is about 0.3 x 20 = 6 KN/m2. I guess this quantity I found out is not very bad to follow, but you must to have your own idea about the actual situation.