Ductility Analysis On The Beam End Of The Prefabricated Pretensioned Prestressed Frame Structure

Prefabricated pretensioned prestressed frame has advantages such as faster installation process,higher quality in production and higher integrity,therefore more and more countries in the world start to adopt this structure.In the requirement of “Green Buildings”,the steel structure and prefabricated pretensioned prestressed frame could be the suitable structure system which could meet the demands of the time.However,due to the assembling requirements of prefabricated concrete structure,the nodes are not as secure as the cast-in-place concrete frame nodes,its integrity has weakened as well.Furthermore,the using of steel strand has changed the ductility of beam.The seismic performance of the whole structure has decreased as well.In order to promote the use of prefabricated pretensioned prestressed frame in the seismic fortification intensity of 7 degrees and above areas,its seismic performance must make a relevant research to assure the safety of actual use.In order to make clear the seismic performance of prefabricated pretensioned prestressed frame structure,a batch of prefabricated pieces of prestressed concrete beams were researched under the low-cyclic load.Based on the experimented results,the finite element model is adopted to analyze the ductility of the members.The model takes account the bond-slip relations between the strand and concrete,the mechanical performance of the concrete under the cyclic load,and the connections between prefabricated concrete beam and column.After a large quantity of trials,the finite element parameters were confirmed,after that the corresponding parametric analysis were made about the factors which could affect the ductility of the members.The restoring force model is established on the basis of experiments and analysis,the results could be a reference of this prefabricated pretensioned prestressed frame structure analysis as Time-History analyze and Push-Over analyze.The results show that the ductility of the prefabricated prestressed concrete beam component could be affected greatly by the concrete compression zone height,reinforced index,shear span ratio and the properties of steel strand.Besides,the concrete strength,the arrangement of stirrups in the roots and the tensile strength of ordinary reinforced in the tension zone could affect the ductility,too.Finally this paper summarized the certain area of each parameter to make the beam member maintains in higher ductility.The established restoring force model fits the test and analysis results well,so the results could be a reference for the later analysis.