Braking Force Distribution

[Darkangel24]

Hello All,

I have a 2 span bridge with Expansion Joints at the abutments and all the bearings are elastomeric. Currently i have distributed the moment caused due to the longitudinal braking force equally to the abutment and the pier, but in actuality, the abutment with pile connection stiffness would be greater than the pier column connection(but due to presence of elastomeric bearings used on abutments and pier shouldn't the forces be equally distributed), SO i am thinking the percentage of moment distributed would be respective of its element stiffness. I am not sure if i should use equally distributed forces or determine the stiffness and then distribute the forces?

 

[ishvaaag]

The kynematics of the movement (out of the taken constant length of the spans) asks for the same absolute displacement of the upper layer of the elastomeric support. Something like in the scheme can be used (can be perfected by including as well some displacement out of the lateral flexibility of the abutments themselves).

 

[ishvaaag]

A SAP2000 model can resolve all the forces single-step, needs not to be made by hand.