Drilled pier allowable lateral
Drilled pier allowable lateral
(OP)
IBC has the following limit on lateral loads on drilled piers. But is there any limit for lateral induced moment transferred from a fixed base column directly into the top of a pier?
1808.2.9.3 Allowable lateral load.
"Where required by the design, the lateral load capacity of a pier, a single pile or a pile group shall be determined by an approved method of analysis or by lateral load tests to at least twice the proposed design working load. The resulting allowable load shall not be more than one-half of that test load that produces a gross lateral movement of 1 inch (25 mm) at the ground surface."
1808.2.9.3 Allowable lateral load.
"Where required by the design, the lateral load capacity of a pier, a single pile or a pile group shall be determined by an approved method of analysis or by lateral load tests to at least twice the proposed design working load. The resulting allowable load shall not be more than one-half of that test load that produces a gross lateral movement of 1 inch (25 mm) at the ground surface."





RE: Drilled pier allowable lateral
Since it is hard to obtain a true fixity, it may be more conservative, to assume a "free head" condition. With this assumption, you can take shear and moment from the column and apply it to the pier head by using beam on elastic equations. You will get larger induce moment and larger top of pier head deflection by using a "free head" condition.
The only limit for lateral induced moment is based on your top of pier head condition (fixed head or free head).
RE: Drilled pier allowable lateral
Do geotechs a normally give a range of combined allowable lateral moments and shears that would cause 1/2" head deflection (for example)or just shears? I have only received allowable shears from the geotech for this project.
RE: Drilled pier allowable lateral
If you have access to Roark's Formulas and Bowles Foundation Analysis & Design book, you can set up your own spreadsheet in few hours. The geotechnical inputs are very minimal.