Methods to Calculate Reaction Forces of Bearings and Girder Displacement During System Transformation of Multi-span Continuous Girder Bridge

Formulas to calculate reaction forces of bearings and girder displacement of continuous girder bridges with different cross-sections and segment lengths are derived based on the basic principles of mechanics, aiming to facilitate the calculation and improve the calculation efficiency. The Haizi Lake Bridge, a continuous girder bridge with a unit of 15 spans, is taken as the prototype bridge to verify the proposed theoretical formulas using finite element analysis. The variation law of reaction forces of the bearings and girder displacement during multiple system transformation processes are studied. The results show that the values from numerical simulation agree well with the values calculated by the theoretical formulas, and the relative errors are less than 5%. Closure temperature of the girder segments on the two sides is a main influential factor of the reaction forces of bearings, with equal cross-sectional areas, the reaction forces of bearings induced by thermal effect would not be affected by the subsequent construction methodologies. Compared with the finite element analysis, the theoretical formulas are easier and more efficient in calculating the reaction forces of bearings and girder displacement of the continuous girder bridge under thermal effect, which can be applied to real engineering construction. © 2021, Journal Press, China Railway Bridge Science Research Institute, Ltd. All right reserved.