Analysis Of Free Vibration Characteristics And Seismic Response Of H-radiant Beam String Structure

For the development of modern construction industries,with the advantages of short construction period,reduction of the usage of on-site labor forces,and the improvement of the construction quality,prefabricated buildings have become an unstoppable trend.Among them,the prefabricated reinforced concrete beam-column joint is an important part of the transfer load and is related to the safety of the overall structure.Related to the safety of the massive structure,when designing the beam-column joint,the requirement of the “strong column weak beam and strong joint weak component” should be satisfied and the requirements for ensuring the strength,stiffness,and ductility of the node area should be ensured preferentially.In this paper,based on the experiments of the experiments results of the beam-column connection,we select a new type of penetrating prestressed beam column joint model.Through analyzing the cast-in-place and assembly type model at different axial compression ratios and concrete strengths by the finite element methods,the shear resistance of the components of the beam-column in different concrete and stirrup strengths was analyzed,and also the seismic capacity of the joint in different compression ratios and components strength.The major researches are shown as follows:(1)We establish the cast-in-place model and a new type of assembly beam-joint model.The new type of model uses prestressed bolt connecting at the joints,and the steel hoop is established in the beam-end in replace of the stirrup.In the process of the model establishment,the nonlinear of the material and the contact non-linear between the bolt and beam.(2)We analyze the components through analyzing the natural vibration characteristics of the cast-in-place and assembled-type models,and changing the parameters of the axial compression ratios,the concrete strength and the prestress.From the numerical analysis results,it can be found that since the effect of the steel plate hoop and the prestressed bolt in the beam-column node of the assembly model,the cast-in-place model has a larger change in the vibration mode of the component than the assembled-type.When the structure has the same constrains,The global stiffness of the structure can be increased through increasing the concrete strength or adding the effect of the prestress.(3)Through varying the concrete and stirrup strengths of assembly-type model,we analyze the shear performance of the beam-column joint.From the numerical analysis results,with the effect of steel plate hoop of the beam end of the assembly-type,when the concrete strength of the beam increases,the hoop can restrain the failure.At this moment,there is shear failure of the diagonal section in the beam,and with the increasement of the stirrup strength,the ultimate loads of the beam also increase.When the stirrup strength increases,the hooping can take a part of the shear effectively,and has the effect of restraining the crack development and extension.The higher the stirrup strength,the larger the shear capacity.(4)We learn the seismic capacity of the assembly-type model,and analyzing the effect of the compression ratios and components strength on the cast-in-place and the assembly type model on seismic.From the results,it can be found that because of the effect of the prestressing bolt of the beam-column joint of the assembly-type,the assembly type model has a better seismic capacity than the cast-in-place model.When the axial compression ratio of the joint increases,the bearing capacity also increases,however,when the ratio goes out of a certain range,there will be a majority of the adverse affect of the effect of the ratio.With the concrete strength growth,the global seismic capacity of the joint also increases.