This dissertation deals with the analysis for long-term behavior of composite girder bridges. Time dependent effects due to the creep and shrinkage of concrete are investigated and the differences in structural behavior influenced by those effects are analyzed.
To consider the varying material properties through the sectional depth, the layer approach in which a section is divided into imaginary layers is adopted. The creep and shrinkage effects of concrete are also considered with the first-order algorithm based on the expansion of creep compliance function.
In sectional analysis of composite girder bridge, a simplified analytical method derived from the equilibrium equations and compatibility conditions is proposed to replace the sophisticated calculation procedures being adopted in the classical creep analysis.
Using the element stiffness matrix constructed based on the assumed displacement field formulation, the long-term behaviors of simple and continuous composite girder bridges considering the construction sequence are conducted. Besides, the characteristics of time-dependent behaviors following the bridge types such as the variation of deflections, and internal forces are discussed in detail.
