Comparative Study of Behavior of Integral and Bearing Type Bridge under Temperature Loading

As temperature changes daily and seasonally, the spans of integral bridge increase and decrease, pushing the abutment against the approach fill and pulling it away. As a result the bridge superstructure, abutment, approach fill, foundation piles and foundation soil are subjected to cyclic loading, and hence understanding their interactions is important for effective design and satisfactory performance of integral bridges In this paper, results of comparative study of behavior of integral and bearing type bridge under temperature loading is shown. For this purpose, three bridges are modelled viz. one span, two span and three span, and the results are compared with bearing type bridges. Computer analysis is done using STAAD Pro software. Soil structure interaction is considered using horizontal spring restraints, whose stiffness is calculated on the basis of earth pressure acting of the back of abutment. Results indicates that as the number of span increases the rate of increase in moment and displacement due to temperature reduces and in three span integral bridge, the intermediate span in both the cases viz. expansion and contraction, experiences very less moment under temperature forces. While in bearing bridges no moments and stresses are observed due to temperature effect because of the provision of expansion joints.