Experimental Study On Seismic Behavior Of Prestressed Precast Concrete Frame Structures

Prefabricated structure has become an important engineering structure in engineering practice because of its Superior environmental advantages and efficient construction speed.However,its mechanics performance depends largely on the connection form of joints.Therefore,when studying this type of structure,if the joint form and key parameters can be properly designed,the mechanics performance of the precast structure will be greatly improved.In this paper,two frames are made,one is a prestressed precast frame,and the other is a comparison frame that is assembled monolithic frame.Through the comparative analysis of the two frame structure manufacturing process and the subsequent quasi-static test results,it is verified that the new prestressed prefabricated frame structure not only reduces on-site wet operation,shortens the construction period,but also has good seismic performance.The research in this paper has the following beneficial conclusions:1.Prestressed prefabricated frame structure adopts prestressed dry connection,which can effectively reduce on-site wet work volume and formwork operation,fast construction speed,and conform to the trend of environmental protection and industrial production.2.The quasi-static test of the two frames is carried out.The results show that the prestressed precast frame has the structural performance that is not weaker than the assembled monolithic frame under the condition of reasonable design and proper parameter selection.The prestressed precast frame is an optional structural form of the current fabricated frame,and has a broad development prospect.The results and analysis of the two frame tests are as follows:(1)Prestressed prefabricated frame structure Beam-column members have fine and dense cracks,small structural damage,small residual deformation and good recoverability.Structural damage is mainly concentrated in the joint parts of the beam and column.By rationally designing the replaceable joints,the technical difficulty and cost of structural repair after earthquake can be greatly reduced.(2)The hysteresis curves of the two specimens obtained by the quasi-static test are relatively full,indicating that both types of frames have good energy dissipation capacity,but the energy dissipation capacity of the prestressed precast frame is slightly lower than that of the assembly.The main reason f is that the energyconsumption of the assembled monolithic frame achieves higher energy consumption through larger residual deformation.The residual deformation and repairability of the structure should be fully evaluated in the actual project.Prestressed precast frame structures will achieve good seismic performance through reasonable design and parameterization.(3)The overall development trend of the skeleton curves of the two frames is similar,and they have experienced three stages of elasticity,yielding and strengthening,and the bearing capacity of the two is equivalent.In this test,the prestressed prefabricated frame stiffness is slightly higher than the assembled monolithic frame,mainly due to the small overall damage of the prestressed prefabricated frame structure.3.Using the finite element software OpenSEES,the factors affecting the seismic performance of the prestressed precast frame are further analyzed: the area of the prestressed tendon,the tensile stress of the prestressed tendon,and the size of the angle steel.The simulation results show that with the increase of the area of prestressed tendons and the tensile stress,the load corresponding to the structure increases,the residual deformation decreases,the restoring force of the structure increases,and the area of the hysteresis loop remains basically unchanged.As the thickness of the angle increases,the load corresponding to the structure increases,the residual deformation increases,the area of the hysteresis loop increases,and the energy consumption capacity increases,but the overall increase is limited.