Research On Seismic Performance Of Prefabricated Concrete Frame With Groups Of Energy Dissipators

With the continuous promotion for industrialization of construction in China,the construction industry welcomes the new opportunity,but also challenging.Great changes is now taking place in conventional construction industry,which is based on the cast-in-site structures.Precast structures(PC structures)have wide application prospects for having advantages of short terms,high quality of construction,improved working conditions,conservation of resources as well as better sustainability.However,the seismic performance of precast frame joints generally falls short,leading to the application-constrained of PC structures in seismic fortified areas.Besides,nowadays populations have more severe demand on the safety of structures with the improvement of material and cultural life.Although it is feasible to improve the aseismic performance of the fabricated building by external shock absorption and isolation techniques,the existing external shock absorption and isolation techniques possess various disadvantages,such as large volume,complex construction,complicated processing technology,inconvenient transportation,large time and energy consumption in construction and installation.Moreover,conventional anti-seismic technologies could not accomplish the goal of multistage energy dissipation.Consequently,it is of great significance to develop a new type of fabricated frame joint overcoming shortcomings above.In this paper,the structural damping techniques both at home and abroad were systematically sorted out and summarized,especially the researches and applications of buckling restrained braces.A new type of longitudinally-cut circular-rod-type buckling restrained energy dissipator with small volume was put forward and a research on its seismic performance was conducted.The main contents of this paper are as follows:(1)5 groups,a total number of 33 longitudinally-cut circular-rod-type buckling restrained energy dissipators were tested under quasi-static load,of which 5 parameters including areas of cross sections,lengths of cut segments,shapes of cross sections,thicknesses of steel sleeves and specifications of steel bars varied in the test.Analyses on failure mode,hysteresis loop,maximum compression strength adjustment factor,effective viscous damping ratio,capacity of energy dissipation,ductility and skeleton curve was conducted demonstrating that the energy dissipators perform good hysteretic properties if proper parameters are selected.Furthermore,the effect of different parameter on the hysteretic behavior was determined and the optimal parameters were chose to ensure good energy dissipation and steady hysteretic behavior.(2)Buckling restrained energy dissipators of various cross-section areas were numerically analyzed through finite element software ABAQUS to provide a reliable method of numerical simulation for further researches.A conclusion could be drawn that results of the numerical analysis were basically in accordance with results of the experiment.(3)A new type of self-centering fabricated frame joint with groups of energy dissipators was designed and further analyzed through finite element software OpenSEES to simulate its aseismic behavior under earthquakes.The numerical simulation results demonstrated that this new-type joints performed well under earthquake action achieving the objective of multistage energy dissipation.Eventually,based on the summery,some suggestions and prospects for futher reseachers on the study of buckling restrained energy dissipators and the energy dissipation joint with groups of buckling restrained energy dissipators were put forward.Through research work above,this paper deeply analyzed the behavior of the new-type energy dissipation joint with groups of buckling restrained energy dissipators under eathquakes providing theoretical and experimental bases for futher studies.