Effect of Link Slab on Seismic Response of Two Span Straight and Skew Bridges

Highway bridges are frequently constructed as simple span structures with steel or concrete girders and a cast-in-place concrete deck, spanning from one pier to another. At each end of the simple span deck, a joint is provided for deck movement due to temperature, shrinkage, and creep. Bridge deck joints are expensive and pose many problems with regard to bridge maintenance. Elimination of deck joints at the support of multi-span bridges has been the subject of recent studies. Recent researches have led to the development of a design concept and approach for jointless bridges where the expansion joints are replaced with continuous link slabs. Further studies have indicated the proper performance of such bridges under service loading conditions. This paper presents analytical study of seismic behavior and response of a two span bridge connected by link slabs. Three dimensional finite element analyses of straight and skew bridges with skew angles varying from 15 to 60 degrees is performed. Both linear time history and response spectrum analyses method are carried out in order to investigate the response of the bridge. The results indicate that the force and displacement demands of the interior bent maybe reduced considerably, if link slab is used in the middle of the bridge instead of an expansion joint.