Basement Wall Analysis (take 2)
Basement Wall Analysis (take 2)
(OP)
I am re-posting a question from a few days ago in the hope that some fresh thoughts from the group are generated. Thank you to all who have replied to the previous post.
The stresses created in basement walls by earth pressures against their exterior faces are resisted by bending of the walls in horizontal and vertical spans. The distribution of the total lateral load between the vertical and horizontal span depends on the height and length of the wall, and its stiffness in the spans. The lateral load on a basement wall will be carried entirely in the vertical span when the length of the wall between supports approaches three and a half to four times the height.
Question: can someone explain where the 3.5 to 4.0 times the height comes from? Either explain the theory or please point me to a code reference (explanation of theory preferred).
Thank you.
The stresses created in basement walls by earth pressures against their exterior faces are resisted by bending of the walls in horizontal and vertical spans. The distribution of the total lateral load between the vertical and horizontal span depends on the height and length of the wall, and its stiffness in the spans. The lateral load on a basement wall will be carried entirely in the vertical span when the length of the wall between supports approaches three and a half to four times the height.
Question: can someone explain where the 3.5 to 4.0 times the height comes from? Either explain the theory or please point me to a code reference (explanation of theory preferred).
Thank you.






RE: Basement Wall Analysis (take 2)
Your value of 3.5 to 4.0 may be a reasonable guide for some situations but it is by no means representative of all. It seems intuitively obvious that when the length of wall becomes large relative to height, the central part of the wall will tend to span vertically, not horizontally. But even in very long walls, the region around the corners is affected by continuity with the wall around the corner. A yield line analysis can be used to approximate the wall's behavior.
BA
RE: Basement Wall Analysis (take 2)
RE: Basement Wall Analysis (take 2)
RE: Basement Wall Analysis (take 2)
RE: Basement Wall Analysis (take 2)
Foundation walls are a beautifully complicated system.
RE: Basement Wall Analysis (take 2)
A good resource would be "Rectangular Concrete Tanks" by the Portland Cement Association. The book provides a number of tables with different edge restraints and varying aspect ratios. It explains how these tables were created and you can see the progession of the moment coefficients to the vertical axis as the wall length increases.
RE: Basement Wall Analysis (take 2)
BA