Steel-concrete composite structures are made of steel and concrete material or composted of steel and concrete sub-structures. Steel-concrete composite structures are widely used in engineering structures due to the satisfying utilization of the two materials of steel and concrete. With the development of technology, new kinds of composite structures and elements are constantly emerging which require the corresponding theoretical guidance. In this research program, the performance of thin-walled concrete-filled steel tubes and composite bridges are investigated by tests and theoretical analysis. Design methods and practical engineering technology are proposed. The research program is supported by a series of research projects such as National Key Technology R&D Program, National Natural Science Foundation of China and so on. The main contents are shown below:
1. An innovative composite structural element ─ thin-walled centrifugal concrete-filled steel tube are proposed. The theoretical model was established and design method was proposed. The thin-walled centrifugal concrete-filled steel tube are used in Ou river crossing electronic transmission tower, Jiao river crossing electronic transmission tower and several electricity substations.
2. The fire resistance of thin-walled concrete-filled steel tubes, new complex section thin-walled concrete-filled steel tubes and thin-walled concrete-filled steel tubes reinforced with lattice angles are studied.
3. The stress concentration factor, static behavior and dynamic behavior of concrete-filled steel tubular connections are investigated. The proposed design method provides reference for the design of ultra-high composite electronic transmission towers including Zhoushan electronic transmission tower, Yuhuan – YueQing electronic transmission tower, and Liuheng electronic transmission tower.
4. The durability of composite bridges in chloride environment is firstly studied. Analysis program for composite beam under hogging moment was developed. Monitor device and corresponding technology was developed. Test device for single stud shear connectors was also developed. Those technology was used in the Jiubao Bridge and Qingshuipu Bridge.
The results of the research program are incorporated into three design standards. In total 80 technical papers are published, in which 44 papers are indexed by SCI, 24 papers are indexed by EI. Four invention patents and two computer programs are authorized. The results of the research program are also applied in more than 10 engineering projects.
