Study On Mechanical Behavior Of Prefabricated Prestressed Frame Joints

Compared with the cast-in-place concrete frame structure,we can find that they have their own advantages,such as light weight,short construction period,energy conservation and environmental protection,small residual deformation of the structure after earthquake and strong self reset ability,which has attracted the attention of many countries.However,we can see from the aspect of energy consumption capacity that prefabricated concrete frame structure is weaker than cast-in-place concrete,and this requires high construction technology on site,and can only be used in areas with low earthquake frequency or low requirements of building structure level.This is the reason why many countries are willing to use cast-in-place concrete.In this paper,prestressed steel strand and angle steel are used as energy dissipation components in prefabricated frame structure,which not only improves the capacity of the whole structure in terms of seismic performance,but also takes the prestressed steel bar and angle steel as energy dissipation components.The structure repair after earthquake is very convenient,and the cost is low.We only need to replace it.In this paper,ABAQUS finite element software is used to simulate the pre-stressed prefabricated joint of additional angle steel,and the numerical analysis is established under low cycle reciprocating load.The specific research contents and analysis results are as follows:?1?ABAQUS finite element software is used to establish four groups of model joints with different prestress size,and mainly in the aspect of joint characteristics.The influence of different prestress on the seismic performance of joints is analyzed.The results show that:the joint with large prestress is stronger than that with small prestress in all aspects,but the applied value of prestress should not be too large or too small,which must meet the requirements of the specification,The prestress of?_{co n}?28?0.6f_ptkis the most suitable.If the prestress is too small,the energy consumption capacity will be insufficient,and the seismic performance will not meet the structural requirements;if the prestress is too large,the concrete at both ends of the prestress will be damaged due to the excessive prestress,and the bolt anchoring the prestressed steel strand will also be invalid due to the excessive prestress.Moreover,if the prestress is too large,the safety requirements in the application process will be higher,which is very easy to occur The accident was caused by operation error.?2?In the same way,ABAQUS finite element software is used to establish two groups of joints:Prefabricated joint with additional angle steel and cast-in-place joint model,and then the two joints are compared and analyzed.The results show that:the cast-in-place concrete joints have greater advantages in load-bearing capacity and structural deformation resistance compared with the prestressed frame joints with additional angle steel.However,the angle steel and prestressed reinforcement of the pre-stressed prefabricated joint with additional angle steel are always in elastic state,and the self recovery capacity of the structure is much better than that of the cast-in-place joint,and the residual deformation is small,which is convenient for recovery after earthquake At the later stage of loading,the elastic deformation resistance capacity of prestressed frame joints with additional angle steel is basically the same as that of cast-in-place joints.