Analysis Of Ultimate Load Capacity Of Concrete-filled Steel Tube Arch Bridges Considering Creep

Concrete-filled steel tube structure (CFST) is more and more applied in the engineeringpractice and especially in arch bridges because it has many unique advantages just like highload capacity and convenient construct and so on. Meanwhile, the stability of the concretefilled steel tube arch bridge also becomes an important concern to the bridge engineers andresearchers. As an important cause of structural geometry nonlinear, concrete shrinkage andcreep has a significant impact on the redistribution of the CFST arch bridge’s section stressand the main arch rib’s internal force distribution. In view of the characteristics of concretefilled steel tube arch bridge, this article mainly researches the ultimate load capacity analysismethod considering the effect of concrete creep, including the following aspects:1. Domestic and foreign research results are summarizes, and the concept of equivalentmodulus bringed in. Based on fiber model of beam structural finite element method, theultimate load capacity analysis method with a consideration of the effect of creep isestablished. Corresponding two different creep models and based on the ultimate loadcapacity program ignoring creep effect, two kinds of FORTRAN programs are worked out.2. Ultimate load capacity analysis is carried out on CFST axial compression members,eccentric compression members and arch ribs members load capacity analysis. The results arecompared with the experiment data or theory data did by some famous scholars, which showthat in this article the programs used to solve CFST arch bridge’s ultimate load capacityconsidering the creep effect are correct and effective. What’s more, the results show that thecreep has an effect on structural deformation and its load capacity.3. To a128m main span CFST arch bridge with a dumbbell section as a research object,four load cases are considered to analyze by the effect of creep. The analysis results show thatthe creep effect on the influence of the arch rib deformation is not allowed to ignore, and onthe influence of the load capacity of the arch rib vary in creep mode and load condition.