Corbel design for torsion

[sam3990]

Hi all
I'm having to design a corbel but it is subjected to torsional moments due to a sign structure being supported by the corbel. Now most of the literature talks about vertical downward and horizontal force creating moment on face of corbel. what about any moment that creates torsion on the face? below image from aashto and a sketch for explanation. can anyone pls share some inputs/literature for design of corbel for this torsional moment. thanks a lot.

 

[ANE91]

Finite element model and strut-and-tie. How substantial is the torsional moment? I doubt it’s much.

 

[KootK]

My recommendation:

1) Split the torsion into an up/down couple.

2) Split the corbel, fictitiously, into two arms that resist [1]. This is akin to warping torsion in steel.

3) Be generous with the ties between the arms for crack control.

A corbel with true net uplift like this presents some special challenges. On the uplift side, the detailing may look different from conventional corbel designs which are predicated on downward load. And you'll want to consider your tension side anchorage setup in conjunction with detailing on that side.

A corbel with torsion and significant axial load can often be treated as a reduction in downward load on one side. This will likely not be the case here.