Research On Seismic Performance Of Cam Response Amplification Device Of Viscous Damper And Isolated Precast Concrete Structures

Compared with the traditional cast-in-place structure,the prefabricated concrete structure has the advantages of high industrialization,short construction period,low labor intensity and little impact on the environment.However,due to the weak joints and poor integrity,the failure of precast concrete members is lighter and the connection parts between the components are extremely serious,which restricts the development of precast assembled concrete structures.Base isolation technology can effectively prolong the natural vibration period of the structure,increase the damping and reduce the seismic action of the input superstructure.The application of base isolation technology to the assembled concrete structure is an effective way to improve its overall seismic performance.Seismic isolation assembly concrete structure will face the problem of shear failure of isolation bearing caused by excessive displacement of isolation layer under rare earthquake.The application of isolation limit technology can effectively limit the displacement of isolation layer.At present,passive dampers are mostly used as isolation layer limiters.The CRAD-VD(Cam Response Amplification Device of Viscous Damper)with viscous damper studied in this paper has the effect of force,displacement an·d velocity amplification.It can convert linear motion into reciprocating linear motion within the limits of vertical direction,and has the characteristic that displacement never fails.The main contents of this paper are as follows:1、Design and theoretical formula derivation of CRAD-VD: Based on the systematic summary,a new type of cam response amplifier device of viscous damper is proposed.The theoretical calculation formula of CRAD-VD is deduced.The hysteresis curve of restoring force model is obtained.The calculation formulas of force,displacement,speed and mass amplification factor are given.2、 Pseudo-static test of CRAD-VD: Two groups of CRAD-VD with different cam eccentricities were designed for pseudo-static test comparison.Sinusoidal wave and triangular wave loaded by displacement control were used in the test.The change rule was studied by changing loading frequency,loading speed and loading amplitude.The experimental results are compared with the theoretical analysis results to verify the correctness of the theoretical calculation formula.3 、 Seismic response analysis of CRAD-VD single-degree-of-freedom Seismic Absorption System Based on MATLAB: The motion equation of CRAD-VD single-degreeof-freedom system is established,and the non-linear analysis program of MATLAB is compiled.Under the action of frequent earthquakes and rare earthquakes,the comparative analysis of the effect,energy,response spectrum and dynamic amplification coefficient of single-degree-offreedom system,CRAD-VD single-degree-of-freedom system and VD single-degree-offreedom system are carried out.4、Seismic response analysis of CRAD-VD two-degree-of-freedom isolation system: The superstructure of the isolation structure is simplified into a single mass,and a two-degreeof-freedom isolation system is formed with the isolation layer.CRAD-VD is used as the limit device of isolation layer to study the limit effect and energy response of two-degree-of-freedom isolation system under rare earthquakes.5、Seismic Performance of Isolated Precast Concrete Structures: Based on ABAQUS,the seismic performance of a 10-storey seismic isolation assembled concrete frame structure under rare earthquakes and rare earthquakes is analyzed.The seismic isolation assembled structures with CRAD-VD and VD installed on the isolation layer are compared and analyzed respectively,and the action rule of CRAD-VD in the actual structure is studied.