Integral bridges (IBs) are jointless bridges where the deck is continuous and connected monolithically with the abutment wall with a moment-resisting connection. With the desire to design and construct longer span bridges with skew and non-skew alignments, and to evaluate of the performance of these bridges during seismic excitation, a new, more integrated analysis and design tool is necessary. This paper describes the implementation of a full 3D finite element (FE) model of an integrated bridge system which explicitly incorporates the nonlinear soil response behind the abutment walls and adjacent to the supporting piles. Using commercially available finite-element code GTSTRUDL (1991), the nonlinear soil behavior is handled using nonlinear springs at the abutment wall and pile nodes. This FE implementation streamlines the analysis and design of IAB systems and is capable of analyzing both skew and non-skew bridge orientations, and should be able to evaluate seismic response. An Integral Bridge of length 50m is adopted for this study. Three bridge models are prepared having single span, two span and three spans. Single span bridge is of 50m length, two spans of length 25m each and three spans of 16.67 each. Three steel girders Integral Bridge has modeled, in which the deck is modeled as reinforced concrete deck. Three Integral Bridge models are selected for this study. It is found that The bending moment in Integral Bridge can be reduced drastically by increasing number of spans and Converting an Integral Bridge into two spans results in reduction of BM upto 75% whereas a three span bridge results in 88% reduction. Converting an Integral Bridge into two spans result in reduction SF 50% whereas a three span bridge results in 66% reduction

Keywords: Integral bridges (IBs), non-skew alignments, span bridges, seismic excitation, deck, jointless bridges, abutment wall.