Question

Explain in details why only panel shear needs to be considered instead of shear at specific section in case of influence line for floor girder.

Answer 1

Floor girders support the panels on which load acts .In the presence of load or when load acts on the panel ,even at a specific point in a panel ,the load is distributed throughout the panel .For example, if we put a point load at a specific point of a panel , the whole panel exerts a certain force on the object supporting the panel , meaning that when load acts on the panel ,the load is distributed throughout the panel .The floor girders supporting the panel will not experience a point load but a distributed load of the panel . Therefore ,in case of influence line for floor girder , panel shear needs to be considered instead of the shear at specific section .