Analysis Of Seismic Damage Evolution Process Of SRC Frame Structure Strengthened With Steel Angles And Strips

The damage of building structure under earthquake is more economical for the repairable buildings to be repaired and strengthened.The steel reinforced concrete structures(SRC)have been widely used in long-span structures and high-rise buildings for their excellent seismic performance while there are few studies on seismic damage evolution of SRC structures strengthened with steel angles and strips.Based on the study on the seismic performance of damaged SRC frame structures reinforced with steel angles and strips,the reasonable finite element analysis models are established to quantitatively analyze the damage evolution process of the steel reinforced frames.Through the research of this paper,the following results are mainly obtained:1.Numerical modeling methods are put forward to reflect the damage degree of structures by material performance reduction,and the relationships between the damage degree and the material reduction factors are founded by using the damage index as the parameter.The experimental models are numerically simulated in finite element software ABAQUS,and the hysteresis curves and the skeleton curves are in good agreement with the curves obtained in the experiment,which shows that the finite element analysis are reasonable.2.Based on the finite element simulation results,the damage values of the SRC frame members and the whole structures strengthened with wrapped steel are calculated.The damage evolution curves of the frame beams and columns are fitted by polynomials.By analyzing and comparing the damage evolution curves of each component,it is found that the damage of frame beams is significantly worse than that of columns,and the damage of bottom layer is more serious than that of upper layers.The damage evolution of components and whole frames is a monotonous and increasing process,which shows that the damage of frame structures under earthquake is an irreversible cumulative process.3.Reference damage index ranges of SRC frames strengthened with steel angles and strips at characteristic points are given.Compared with the unreinforced SRC frame structure,the damage values of frames reinforced with external steel are smaller at yield point and peak point,showing that the reinforcement can make damaged SRC frame recover or even surpass the ability of original SRC frame to resist earthquake damage and further proving the effectiveness of external steel reinforcement.