Effects of connection flexibility in steel-concrete composite beams due to live loads

The paper describes the girders of bridges made of steel beams connected in a flexible way with a concrete deck slab. There are analyzed internal forces and displacements versus the changes in the connection degree that are due to variable cyclic loads occurring in bridges. The analysis of the problem is based on a classical parameter characterizing the connection flexibility Cz and supplied with the coefficients μ and β defined by authors. They allow the connection degree of a combined girder to be estimated. There are analyzed two solutions to the problem of partial interaction in composite steel and concrete girder: a linear one based on the solution of analytical form (differential equations) and a non-linear one based on mechanics of clearances. The latter solution accurately shows the work of connectors in bridge spans. The analysis is illustrated by numerical examples of a real composite bridge. The attention is focused on the diagrams showing various shapes of curves representing the coefficients μ and β.