Model of bridge with supports activated under heavy load

Abstract

Road bridges can sometimes be used exceptionally for nonstandard loads (heavy cargo). This article presents structural analyses of a bridge loaded by a 620-ton vehicle. The case in question concerns a specially reinforced bridge. Its specific feature is the use of additional frame supports, which are activated only when loads significantly exceed the service load. Therefore, the structure’s structural system is variable, and the additional support is activated during increased load intensity. The article demonstrates that the results of field tests performed during abnormal loads are necessary to properly model the structure. It is also essential to determine the degree of interaction (bonding) between concrete deck slab and the steel beams, the load distribution among the girders, and the stiffness of the frame supports, considering the unintended gaps between the span and the frames.