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The steel-concrete composite bridges started to be designed in the  30s of the last century . They are formed with a concrete deck and steel beams , which can be an I section  or a box girder . Despite the configuration , the final solution strongly depends on the engineer experience due to the great number of design variables. Therefore , it is intended to archive better economical solution with the help of optimization procedures.

Composite bridges are more popular around the world since they combine some advantages of steel bridges with some key factors of concrete bridges. In fact, a composite bridge presents the following:

A steel main structure that is much easier to erect if compared to the construction of a concrete girder

A light structure, which imposes smaller loads on piers and foundations, allowing for economy

A concrete slab, which is cheaper and easier to build than a steel orthotropic deck, and also presents two other advantages