Study On Seismic Performance Of Spine-frame Damping Structure

How to simultaneously reduce the drift ratio,floor acceleration,and residual deformation of the frame with elastic vertical element under earthquake is the key to further improving its seismic resilience as floor acceleration may be greatly increased by the highermode response triggered by elastic vertical element.This dissertation takes the spine-frame system as the research object,and two kinds of spine-frame structure with supplementary damping(SFD)are proposed: 1)spine-frame structure using rotary damper as the momentlimiting connection between the spine and frames,and 2)spine-frame structure arranged damper between adjacent floors.The dampers suitable for the above two SFD structures are proposed: 1)rotary friction damper with a decoupled bending and shear resistance capacity;2)lead viscoelastic damper with single shear plate and multi-lead rods.The main research object includes studying the mechanical properties of the two dampers,revealing the damping mechanism of the two SFD structures,finding out the influence of the mechanical parameters of the dampers on the dynamic response of the two SFD structures,and investigating the seismic performance and uncertainty of the two SFD structures.The main research contents are as follows:(1)Study on mechanical properties of rotary friction damper with a decoupled bending and shear resistance capacity(RFD): The wear-resistance of metallic friction shims and brake pads was investigated by quasi-static test;The advantage of RFD compared to the traditional rotary friction damper was study by numerical analysis;And the mechanical properties and repeatability were investigated by quasi-static test.(2)Study on mechanical properties and mechanical-model parameters of lead viscoelastic damper(LVD)with single shear plate and multi-lead rods: Two connection configurations for LVD with single shear plate and multi-lead rods were proposed;The effects of deformation,frequency,fatigue,temperature,aging and repeated loading on the mechanical properties of the LVD with single shear plate and multi-lead rods was investigated;The mechanical properties of the two types of LVDs with different product design parameters were compared;The change of the mechanical properties of the LVDs under six-times repeated loading was studied;And the parameters for bilinear,Bouc-Wen and Steel-MPF mechanical model were given based on the test results.(3)Establishment of an uncertainty-reduced numerical model of spine-frame structure: An optimization algorithm based on updated probability is proposed to reduce the uncertainty in numerical parameters;An overview of the shaking table test of full-scaled four-story spine-frame structure is introduced;And an uncertainty-reduced numerical model of spine-frame structure is established by applying optimization algorithm based on updated probability in combination with the shaking table test.(4)Demand analysis and prediction method of spine stiffness in spine-frame structure: The calculation sketch of the spine in the spine-frame structure was established according to the internal force distribution law,and the formula of stiffness ratio of the spine to frame was derived;The coefficient of variation in drift ratio and the normalized minimum drift ratio were proposed to measure the degree of uniformity of story deformation;A parameter analysis based on the uncertainty-reduced numerical model of spine-frame was carried out to investigate the effect of stiffness ratio of the spine to frame on the degree of uniformity of story deformation,and formula of the stiffness ratio-floor deformation uniformity was given by the 5th polynomial fitting;And the prediction method for spine stiffness demand was established.(5)Study on seismic performance of spine-frame with supplementary damping:The design procedure of SFD structures was proposed;The damage mechanisms of three kinds of reference structures(ordinary frame,spine-frame,and spine-frame with forcelimiting connection)and three kinds of damping structures(frame with LVD,spine-damping frame,and spine-rotary damping-frame)were revealed;The influence of damper parameters on the dynamic response of the three kinds of damping structures was investigated;And the seismic performance of three kinds of reference structures and three kinds of damping structures was compared under different seismic risks.(6)Uncertainty quantification of the seismic performance of the spine-frame structure with supplementary damping: A probabilistic model to represent the uncertainty in mechanical properties of the damper between real practice and software was established,which is a normal distribution model with a standard deviation of 0.05 times its mean(3σprinciple);2000 groups of samples of each damping structure were generated by randomly sampled the mechanical parameters of each damper;And the effect of uncertainty from mechanical parameter of damper on the dynamic response of the three types of damping structures and characteristic response of damper was quantified.The above studies show that: the maximum drift ratio,floor acceleration,and residual deformation of the two SFD structures proposed in this paper were smaller than those of the spine-frame structure under three seismic risks;The maximum floor acceleration of the spine-frame with force-limiting connection was smaller than that of the spine-frame structure under various seismic risks,but the coordination effect of spine on the uniform deformation of each story of the frame was weaken due the yielding of force-limiting connection for controlling the floor acceleration,resulting in a bigger maximum drift ratio and residual deformation of the spine-frame with the force-limiting connection under three earthquake risk compared to spine-frame structure;And it is feasible to improve the seismic resilience of the frame with elastic vertical element by using additional damping to reduce the displacement Angle,acceleration and residual deformation simultaneously.