Experimental Study On Seismic Capacity Of Edged Joints Of Precast Prestressed Concrete Frame

The structural system, formed by the introduction of post-tensioned tendons in the pr ecast concrete frame structure, has advantages of precast systems, such as high constructi on speed, low pollution, assurance of quality and durability, etc. Furthermore, it also has following merits of its own. First, it’s helpful to realize the "beam end plastic hinge en ergy dissipation mechanism". Second, the damage of structure induced by earthquake is e asy to estimate. Third, it has high self-centering capacity, small residual displacement, an d convenient repaired after earthquake. However, poor overall performance, joint dependa bility insufficient and poor energy dissipation often make the application of the assembly structure restricted at the earthquake zone. Unbonded posttensioned assembled concrete s tructure have bright future of development and application, yet, research on their seismic capacity and design methods is few. Taking above matters into account.it is necessary t o study seismic behavior and design methods of this kind of structure system, and thus t o extend its application in China.In this paper, based on the experiment on four fabricated unbonded prestressed conc rete frame structure side nodes under low reversed cyclic loading, the stress process, fail ure pattern, hysteresis behavior, ductility, deformation displacement restoring capacity, stiff ness degradation and energy dissipation capacity of the frame are studied. Research show s that the four single-span components deformation condition are basically the same expe rienced elastic, yield and limit three parts, components and the ductility of the deformati on self recover ability is very good; From the damage of the four test component, it ace orded to the design, mainly concentrated in beam-column joint deformation of the mortar, while component itself damage deformation is tiny; The bearing capacity of the compon ent with initial tension stress and prestressed tendons area, increases, the energy dissipati on capacity with prestressed initial tension stress increasing, lower. This shows the prestr essed reinforcement reduce the energy dissipation of the structure.By deformation mainly concentrated, the iteration solution method on the beam mom ent-rotation one-way process of loading was set up. In this method, we presumed that th e fabricated unbonded prestressed concrete frame structure under horizontal loads was ass igned to the deformation completely the joint mortar. Comparing the iteration results and the experimental results, it shows that the simplified calculation method has a certain pr ecision, and can meet the practical requirement of design.We have used ANSYS workbench12.1to simulate the test component by finite ele ment analysis. For the processing of workbench interface, we realized effective definition of the unbonded prestressed and the assembly connection surface. The simulation results coincided with the experimental results, that the simulation has certain precision, can ve rify and perfect the research content.Whether the test results or the simulation results can recognize that, while the layers displacement angle achieved3%,the damage only occur on the mortar and beam-column itself don’t. Therefore, fabricated unbonded prestressed concrete frame structure as its go od displacement restoring capacity, the residual deformation small and concentrated, easy to repair after earthquake, reasonable seismic measures taken in the case, can be used in the zones.