Prestressed & Post Tensioned Bridge 1

[Mac75]

I am doing an assessment of a bridge which has span 1 & 4 Prestressed Beams and Span 2 & 3 Post Tensioned Beams. The beams at intermediate supports are sitting on rubber bearing pads.

I have modelled the bridge as 2D Grillage.Do I need to model the hogging section properties for the beams over the intermediate supports?

How do i model the stiffness for rubber bearing pads in my model.

Any help would be great.

 

[ishvaaag]

Certainly modeling any transversal members present is good since affect the behaviour under asymmetrical loadings.

Respect the pads, they have linear spring behaviour in x, y and z directions, x and y shear rigidity, and z compressive; if of substantial dimension have even stiffness against rotation that you can add directly on a support point after its estimation or subdivide the support points as to be able to provide the rotational stiffness.

Regarding values for E and G some investigation of the kind of elastomeric support may be interesting, if not look in AASHTO or fabricators typical values for the bearings.