Study On Seismic Capacity Of A Pre-stressed Swing RC Frame Damaged During Main Shock But Repaired By Using Quasi-static Test

The study on the seismic performance of pre-stressed swaying self-centering RC frame structures began in the 1990 s.For this type of structure,the precast RC(reinforced concrete)beams and columns are connected in series by clamping force provided by unbonded post-tensioning tendons,allowing the beam and column joints to rotate relatively to each other.The damper installed on the beam and column joints is used to dissipate seismic energy,and the pre-stressed tendons are used to provide the structure with the ability to self-centering after earthquake.A large number of studies have shown that this type of structure has excellent seismic performance and post-earthquake self-centering ability,which can ensure the structure to quickly restore the functionality after the earthquake.At present,there are still two problems to be studied for this this type of structure :(1)actual earthquake events are always followed by intensive aftershocks.What is the residual bearing capacity of the pre-stressed swaying self-centering structure damaged in the main earthquake ?(2)The pre-stressed swaying self-centering RC frame has a larger interlayer deformation than the conventional cast-in-place RC frame,and the conventional infilled wall will cause severe damage after the earthquake,which is not conducive to the restoration of the function of the structure.Therefore,it is of great significance to study the new infilled wall suitable for this kind of structure.Based on the above background,this paper studies the residual seismic capacity of a pre-stressed swaying self-centering structure specimen which has suffered extremely rare ground motion and caused damage in shaking table tests.The joint damper is replaced and two different types of ALC panels infilled walls are installed to carry out reciprocating loading quasi-static tests.The applicability of the new wall panel system in the pre-stressed swinging self-centering structure is also studied.The chief study contents of this paper contain:(1)Two kinds of ALC infilled walls can be installed on pre-stressed swinging self-centering frame: rotary ALC panel installed by rotating straight screw method and traditional ALC panel installed by hook bolt method are designed.The design ideas and concrete design methods of two kinds of infilled wall panels are given.(2)A pre-stressed swaying self-centering RC frame was damaged by rare earthquake in shaking table tests.The dampers of beam-column joints and column-foundation joints are improved and replaced,and two types of ALC panels are installed.The reciprocating quasi-static tests are carried out to observe and record the phenomenon and response of the structure in the process of loading and unloading.(3)The structural damage phenomenon and test data in the above tests are analyzed in detail,and the hysteretic characteristics of base shear-peak displacement,skeleton curve and stiffness degradation law,the opening angle of each component node,the performance of pre-stressed tendons and additional energy dissipation dampers of beams and columns,and the comparison of the damage pattern of the two wall panels are obtained.(4)The seismic performance of this structure model under 8 degree rare earthquakes is evaluated by capacity spectrum method,and the displacement and failure states of the structure are analyzed from the performance points,and the damage control effect of the self-centering structure is investigated.