In order to study the bending capacity of steel and concrete composite girder with concrete filled tubular flange (SCCGCFTF), a formula for the ultimate bending capacity of normal section was proposed based on perfected elastic-plastic model for steel and restricted concrete model for inner high performance self-compacted concrete. Analysis result shows that the mechanical behavior under static load can be divided into two phases in accordance with confining effects. Confining effects strength of the concrete-filled steel tube flange was relation to the restriction effect coefficient ξ. The ratios of the calculated value to the experimental ultimate bending capacity were between 0.93 and 0.97. Therefore, the theoretical formula is relatively safe to calculate the ultimate bending capacity.

In order to promote the applications of steel and concrete composite girder with concrete-filled tubular up-flange (SCCGCFTF) in practical bridge engineering, some actual issues for SCCGCFTF bridge structures have been discussed. The finite element static and dynamic analysis models of SCCGCFTF and conventional composite I-shape girder (CCIG) bridge structures were established. Then the stiffness, stress and dynamic characteristics of these composite girder bridges were studied and compared. Based on the numerical analysis results, the mechanical characters of SCCGCFTF bridges are obtained, and some design rules for SCCGCFTF bridges are also proposed. The analysis results show that SCCGCFTF bridges have high practical engineering application value.

There are many old steel bridges on Chinese transportation lines, which keep their normal traffic service function. The old bridges are often required to carry an increasing volume of traffic and heavier vehicles than the original design, so bridge management departments pay more attention to the actual remaining fatigue life of such structures. Based on probabilistic fracture mechanics theory, the member and the system fatigue failure evaluation models for old steel bridges are all proposed, and the fatigue reliability analysis program is developed using Monte-Carlo. As a case study, the evaluation models are used to predicate the fatigue reliability of Zhejiang Street Bridge. According to evaluation results, the probabilistic remaining fatigue life, safe inspection intervals and maintenance strategy are determined.