Study On The Mechanical Properties Of Joints Between Circular Steel Tubular Columns Filled With Steel-reinforced Concrete And Beams Under Low Frequency Cyclic Loading

With the perfection day by day of the Concrete-Filled Steel Tube theory and the wide application in engineering, the joint between the column of concrete-filled steel tubes and the beams has become one of the key technology problems of studying in the structure of concrete-filled steel tubes. Therefore, the deep study on the dynamic behavior of the joints above-mentioned will contribute to promoting the structural design and engineering application. The columns employed in the paper are a new type of steel-concrete composite column, circular steel tube column filled with steel-reinforced concrete. In this kind of steel-concrete composite column, the section steel figured as ' 十' is inserted into concrete-filled steel tube column. The beams used in the paper include steel-I beams and steel-box beams. Based on experimental and theoretical analysis, the dynamic behavior of this new type of joints between column and beams is researched. This thesis carried out following aspects:1. Eleven joints have been designed in the experiment ,of which eight are steel-I beams figured as 'I',the others are steel-box beams figured as 'D'.The design scheme and the process of manufacture of these joints are mainly described. In addition, the paper introduces the loading scheme and test apparatus.2. The dynamic behavior of these joints under low frequency cyclic loading is also investigated, of which the beam sections of these specimens are figured as 'X'and ' 口'.In term of the data obtained from the experiment, the index of seismic behavior to the joints are achieved, such as proportional coefficient on energy consuming and the coefficient ductility on displacement . By means of analyzing the index, we can know the properties of these new types of joints of steel-concrete composite columns. Thereby, the main factors that include the confinement index (θ), the steel embedded index (ρ) and the axial load ratio (n), etc are discussed, which influenced the dynamic behavior of this new type of steel-concrete composite column.3. In order to know the service behavior and bearing capability of this new type of joints entirely, it's necessary not only to analyze the data of experiment but also to make use of software ANSYS doing the finite element analysis on the structure of joint. In this paper, the finite element analysis results will be compared with the data of experiment. And the comparison show that the finite element model could be used to analyse this type of joint because of their good results.The test results show that these beam-column joints can provide very high shear strength and excellent quake-resisting property. Through analysing these results of the test, the conclusion drawn from this paper can be used as a reference for engineering practice.