Secant Piles

[burnhakp]

I have a 3'10" diamater secant pile with a W27x84 soldier pile spaced everyother pile (6.25'). The compressive strength of the concrete is 4 ksi.

How can I determine the composite bending capacity of the the secant pile? I am currently exceeding the bending moment of the wide flange and need to start taking into account the strenght of the concrete.

 

[Once20036]

I'd start with AISC 13th edition p 16.1-83 for design of composite members under flexure.

 

[FixedEarth]

If we assume it as a cantilever system, then you can ignore the unreinforced piers. The section modulus of the reinforced pier is (pi x DIA^3/32). Since this section modulus is much greater than the the W section, assume it as plain 4 ksi concrete pier, and use your retained height, spacing and earth pressure & surcharges to determine embedment depth.

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