不同加载模式下方钢管混凝土力学性能试验研究与理论分析

对钢管和混凝土同时受力和核心混凝土受力的构件进行了试验研究,考虑了钢管和混凝土之间的粘结力对构件力学性能的影响。同时采用有限元法对钢管和混凝土同时受力、核心混凝土受力和钢管存在初应力的构件进行了理论分析。理论分析结果和该文的试验结果进行了对比,验证了理论分析的正确性。在此基础上对比分析了3种加载模式下构件受力性能的异同,分析了钢材屈服强度、混凝土强度、含钢率等参数对构件力学性能的影响。研究表明:当含钢率较低时,钢管与核心混凝土同时受力构件的刚度和承载力要明显高于核心混凝土受力时构件的刚度和承载力;在3种不同加载模式下,试件的承载力都要高于钢材和混凝土两者承载力的简单叠加;核心混凝土受力时构件的延性要优于同时受力时构件的延性;钢材屈服强度对核心混凝土受力构件的承载力影响很小,提高钢材屈服强度能提高构件的延性。

BEHAVIOR OF CONCRETE-FILLED SHS STEEL TUBES UNDER DIFFERENT LOADING CONDITIONS

The experimental research has been made to study the behavior of specimens under different loading conditions, which include the steel tube and core concrete to be simultaneously loaded, only the core concrete to be loaded, only the core concrete to be loaded together with grease between steel tube and core concrete. At the same time, the finite element method is used to analyze the behavior of concrete-filled square hollow-section (SHS) steel tube under different loading conditions. The accuracy of the proposed method is assessed by comparing the analytical values with corresponding experimental ones. For the three loading conditions, the results show that the difference on bearing capacity will become larger with the increase of steel ratio. For the single concrete core specimen with lower steel ratio, the bearing capacity is the lowest, but its ductility is the best. With the increase of steel yield strength, the bearing capacity will increase evidently for the specimen loaded simultaneously. While for the specimen with core concrete, the steel yield strength has little influence exceptincrease of the ductility.