Study On The Bearing Capacity Of Concrete Filled Steel Tubes

Concrete filled steel tubular (CFT) structure is playing a decisive role inmodern civil engineering. Its excellent properties like high bearingcapacity, light weight, good plasticity and toughness, fatigue and toughnessresistance, saving steel have made it one of the most widely usedstructures. This thesis investigates the mechanical properties of fly-ashconcrete filled steel tubes through experimental methods.This thesis first carries out axial compression tests on79cement fly-ashconcrete filled square steel tubular stub columns, analyzes and discusses themechanical behavior of concrete filled steel tubular stub columns under axialcompression, and explores the effect of fly ash addition and steel ratio onthe ultimate strength of concrete filled steel tubes. Then this thesis studies thebearing capacity of cement-free fly ash concrete filled steel stub columnswith different lime addition and steel ratio, and obtains the constitutiverelations of the core concrete by analyzing the experimentaldates. Subsequently, the thesis derives the theoretical formula calculating theultimate strength of cement-free fly-ash concrete filled steel tubes undereccentric compression. Experiments on8cement-free fly-ash concrete filledsteel tubular stub columns under eccentric compression are implemented andexperimental results are obtained. Both results are evaluated.