Numerical analysis of time-dependent behavior of pre-cast pre-stressed concrete girder bridges

This paper deals with the analysis of uncertainties associated with the behavior of bridges constructed with pre-cast pre-stressed girders and a continuous deck. To analyze the long-term behavior of bridges, an analytical model which can simulate the effects of creep, the shrinkage of concrete, and the cracking of concrete slabs in the negative moment regions is introduced. Based on the equilibrium of forces and the compatibility of strains with time, the prediction of stresses and strains in the constitutive materials at any time is achieved. To consider the different material properties across the sectional depth, the layer approach in which a section is divided into imaginary concrete and steel layers is adopted. An element stiffness matrix is constructed according to the assumed displacement field formulation, and the creep and shrinkage effects of concrete are considered in accordance with the first-order recursive algorithm based on the expansion of the compliance function. Correlation studies between analytical and experimental results are conducted with the objective of establishing the validity of the proposed model. Also, many parameters related to the continuity of spans are analyzed to minimize deck cracking at the interior supports. (C) 2002 Elsevier Science Ltd. All rights reserved.