Pier Cap Design for Overhead Sign Structures
Pier Cap Design for Overhead Sign Structures
(OP)
Hi,
I am looking into the design of drilled shaft foundations for overhead sign structures. I was wondering if anyone knows of a good reference for structural design of a "pier cap" that connects a pair of drilled shafts?
Attached is a sketch of what I am trying to describe.
Thanks for the help,
Dale
I am looking into the design of drilled shaft foundations for overhead sign structures. I was wondering if anyone knows of a good reference for structural design of a "pier cap" that connects a pair of drilled shafts?
Attached is a sketch of what I am trying to describe.
Thanks for the help,
Dale





RE: Pier Cap Design for Overhead Sign Structures
Jim
RE: Pier Cap Design for Overhead Sign Structures
RE: Pier Cap Design for Overhead Sign Structures
This pier cap will have a moment of +/- 600 kip-ft, shear of +/- 30 kip, and column load of +/- 15 kip, applied at the base of the overhead sign structure. The drilled shafts will be 42" diameter with an 8 ft c-c spacing.
I briefly looked at the strut and tie model. It appears that the strut and tie model is better suited to handle a concentrated axial load which produces a moment in beam. Is this correct? Is there a strut and tie model that is tailored to applied moments rather than concentrated axial loads?
RE: Pier Cap Design for Overhead Sign Structures
Strut and tie would indeed be suitable approach given the typical proportions for these kind of things.
To my knowledge, there is no such thing as explicit moment in a strut and tie model (as there would not be in a truss). Moments are typically decomposed into force couples.
I've made an STM suggestion below. I think that your first step should be to ditch those J-bolts and get yourself some real anchorage.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.