Nonlinear Analysis Of Mechanical Properties Of Prestressed Steel Reinforced Concrete Frames

Throughout the history of Chinese architectural development,since the reform and opening up,China has invested a large amount of power to develop new types of buildings.Today,with the rapid development of the economy and the continuous improvement of living standards,human beings have made significant progress in building structures.Especially in the process of continuous urbanization,various types of buildings emerge in an endless stream,and in the construction process,high-rise and long-span building structures are used more and more,and the quality is continuously improved.At the moment when buildings such as high-rises and large-spans are becoming more and more popular,with the needs of human life production,on the basis of the original concrete structure,the rapid development of new-type steel-concrete frames has become an important development direction of today's new structural systems.The steel reinforced concrete frame structure can meet the requirements of modern space and meet the requirements of bearing capacity and seismic performance.It is one of the important research directions in the field of building structure in the futureBy reading a large number of documents,it is found that some scholars have proposed a new type of steel-concrete frame with prestressed steel-concrete beams as frame beams and steel-reinforced concrete columns as frame columns.On the basis of this,Fu Chuanguo analyzes prestressed and non-prestressed.The seismic behavior of the stress-type steel concrete frame under verticalloads and low-cycle reciprocating loads was tested.According to the experimental results,the failure state and hysteresis curve of the two truss frames under load are analyzed,and the seismic performance of the two truss frames is summarized.However,the microscopic state and stress strain of the two truss frames are not analyzed in this experiment.Therefore,based on this test,the mechanical properties of two single-storey single-span prestressed and non-prestressed steel reinforced concrete frames are analyzed in detail by using finite element software.(1)Based on the three-dimensional element theory,ABAQUS software is used to introduce the modeling process of the finite element model in detail,and then the calculated skeleton curves are compared with the experimental hysteretic curves.It is found that the two curves are basically identical,and the initial stiffness and ultimate bearing capacity are close.(2)By analyzing the stress-strain state of the two frames and observing the stress-strain state carefully,it is found that plastic hinges are formed at the bottom of the frame column at first.With the application of horizontal load,plastic hinges begin to form at the end of the beam and gradually develop into the span of the beam,which is basically similar to the test results.(3)Based on the theory of fiber beam-column element,OpenSEES is used to simulate the hysteretic behavior of two frames under low-cycle reciprocating loads,and the hysteretic curves are compared with the experimental hysteretic curves.It is found that the hysteretic curves are similar in stiffness degradation and hysteretic loop shape.Then,10 parameters,such as slenderness ratio of columns,axial compression ratio and concrete strength,are analyzed.The effect of axial compression ratio on the hysteretic behavior of frame is obvious,and both of them are the main influencing factors.(4)Based on a large number of data obtained from parameter analysis,the restoring force model and its parameter calculation formulas of prestressed steel reinforced concrete frame structure are deduced by using mathematical software MATLAB regression,and compared with the numerical hysteretic curve,the effect is good,which proves that the formula can achieve a better effect in predicting the hysteretic performance of such frame based on borizontal load.