Analysis On Prevention Of Progressive Collapse For Concrete Filled Steel Tubular Column—Steel Reinforced Concrete Beam Composite Frame Structure

As the important performance of building structures, the progressive collapse resistance of building structure is highly valued in the engineering field. So far, the research on collapse resistance of building structure is mainly focused on the reinforced concrete structure, steel structure and masonry structure. But the study on progressive collapse resistance of composite structure is relatively less. There is no specific applicable normative provision in specific design. Therefore, this paper mainly studies on resistance distribution of progressive collapse resistance of composite structures, collapse resistant capacity of the structure is assessed, and law of internal force response of the structure and displacement dynamic coefficient of remaining structure are obtained. The specific research content and research results are as follows:(1)The typical transverse cross single corridor type concrete filled steel tubular column— steel reinforced concrete beam composite frame structure is designed by using PKPM software to make sure that the model conforms to the requirements of design code. The model of concrete filled steel tubular column — steel reinforced concrete beam composite frame structure built by using finite element software ANSYS13.0.In modeling, the combination of steel and concrete is simulated by choosing reasonable material constitutive relation and the custom section function of ANSYS.(2)Considering the combination of line stiffness and the constraint condition change of the beam within the scope of invalid columns before and after the column failure, four kinds of the most unfavorable condition are preinstalled. Through the method of alternative load path,nonlinear transient dynamic analysis of the remaining structure is carried out. Besides,investigating internal force time history variation of the beams and columns within the scope of columns which lose of function, continuous collapse resistance, law of internal force response of the remaining structure and displacement dynamic coefficient of the remaining parts of the structure are obtained.(3) The results of the research proved :Removing the columns of different parts, the displacement dynamic coefficient of progressive collapse resistance of the remaining structure differs considerably, and the coefficients the largest when removing the middle columns in the long side;The amplitude of variation of linear stiffness within the limit of column which loses its function is the major factor which has a great influence on internal force response of the remaining structure, and inertia effect of column failure on internal force of beam and column focus the direction of the greater change of line stiffness of beam before and after the column failure, but the influence time is short; The ability to continuous collapse resistance ofbeams is stronger than that of the columns; Under such four conditions, the structure does not collapse, and has good resistance to progressive collapse.(4)According to the results of the comparative analysis, some measures of resisting progressive collapse are taken.