Fundamental Study on Elasto-Plastic Behavior of Concrete Encased Steel Members

点击翻译按钮获取中文摘要

1. The ultimate compressive load of concrete-encased steel short columns with circular cross-section is 1.3-1.6 times the cumulated load of the squash loads of the isolated steel tube and confined concrete. This is because the confined concrete is subjected to triaxial stresses at the ultimate state and then its apparent compressive strength increases.2. The ultimate compressive load of concrete-encased steel short columns with rectangular cross-section can be approximated by the cumulated load of the confined concrete squash load and the steel plate ultimate load evaluated as the ultimate compressive load of a plate with all the edges built-in.3. The mean shear stress-slip displacement curves at the interface of the outer steel plate with small ribs and confined concrete in the composite member were obtained having the rib height as parameter, and the transference mechanism of the force in the outer steel plate to the confined concrete is formulated.4. The ultimate torsional moment of composite members with rectangular cross-section is 1.17-1.23 times the cumulated torsional moment of the fully plastic torsional moment of the outer steel plate and the collapse torsional moment of the isolated concrete section. However, supposed that the ultimate shear stress of confined concrete is taken as 0.5 tines the compressive strength of concrete, the ultimate torsional moment can be accurately evaluated by the cumulated torsional moment.5. Composite members subjected to compression or torsion possesses such an excellent ductility that no reduction of strength is observed even after the ultimate state.