STIFFNESS CORRECTION METHOD FOR LONG-TERM DEFLECTION CALCULATION OF STEEL-CONCRETE COMPOSITE BEAM BRIDGE

摘要

This paper presents a model test research on longterm deflection of prestressed steel-concrete composite beams caused by creep and shrinkage effects of concrete. The model is designed based on a 20.8m length segment of a service composite beam bridge in Guangzhou (with the main span length of 50 + 70 + 60m). Geometric scale between the model and prototype is 1:8. Long-term deflection of the test model changing with the time was obtained using 300 days' testing results. In addition, using the CEB-FTP (1990) criterion, effective modulus of concrete was calculated considering the effect of the concrete creep and shrinkage. Uniform the effective modulus of concrete to the modulus of steel, the value of structure stiffness changing with time can be calculated with single material theory, and establish the relationship between stiffness and deflection by introducing stiffness adjustment coefficient, then the value of deflection changing with time can be calculated.