Study On The Pseudo-static Test Of Self-centering Pier With Sacrifice Component

The self-centering pier structure adopts the design of separation between pier and abutment.In the case of strong earthquakes,the pier is lifted and swayed to isolate the earthquake.After the earthquake,the self-centering is achieved by the self-weight,upper load and self-centering steel bars,which can play the dual role of protecting the pier and the abutment.It has one of the research hotspots in recent years.At present,a series of self-centering pier models have been proposed,but most of the self-centering rocking seismic isolation piers are close to the center of gravity of the pier in the horizontal direction when the pier bottom is lifted away,which makes the pier easy to overturn;In addition,the anti-overturning moment provided by the rocking seismic isolation pier device so small that can hardly maintain a large initial rigidity,so it is not suitable for high-speed railway bridges.At present,there are few researches on the rigid base lifting and Rocking Isolation,and there is no theoretical support in the existing finite element model about the setting position of the lifting spring and the value of the spring stiffness,and no scholars carry out experiments to verify it.Based on the current development status of self-centering piers at home and abroad,this paper designs and fabricates a set of self-centering model piers with sacrificial parts based on pier 9 of Yangbi No.1 Bridge of Yunnan Ruili Railway,and the quasi-static test is carried out.The finite element numerical analysis was carried out on Open Sees platform.By comparing the results of experiments and numerical analysis models,the seismic performance of selfcentering bridge piers with sacrificial component is evaluated,and the validity of the numerical analysis model is verified.It is hoped that this pseudo-static test and numerical simulation will provide reference and help for subsequent scholars to carry out research on the performance of self-centering piers with sacrificial component.The main work of this paper is as follows(1)Summarized the development process of self-centering rocking pier at home and abroad,combs the research work and research results of self-centering pier from the design concept,numerical simulation,experimental research,engineering application and other aspects,the previous design and practical experience was summarized,meantime it also pointed out the shortcomings of the existing research.(2)Based on the basic principle of self-centering rocking isolated bridge pier,a new type of self-centering bridge pier structure with sacrificial components was explored,and a selfcentering model bridge pier with scale ratio of 1 / 30 was designed and manufactured.Pseudo static tests were carried out under three working conditions as pier without sacrificial components and pier with sacrificial components of different diameters to explore the isolation principle and isolation effect of self-centering pier with sacrificial components.(3)The hysteretic characteristics,skeleton curve,pier top displacement,pier bottom rotation angle and other data of the self-centering pier model under different working conditions were obtained through the pseudo-static test through quasi-static test,The energy dissipation capacity,lateral stiffness and seismic mechanism of self-centering pier with sacrificial components were studied.The results showed that the existence of sacrificial components restricted the pier bottom slippage,lift-off of the self-centering pier and the rotate angle of the pier bottom,increased the energy consumption capacity of the self-centering pier,and improved the horizontal lateral rigidity and lifting of the self-centering pier.The sacrificial components had the functions of both self-centering reinforcement and energy dissipation components.The larger the diameter of sacrificial component,the more obvious its effect.(4)Based on the existing two-spring model,the hysteretic model of the sacrificial component element was given,and the self-centering pier calculation model with the sacrificial component was established,and the finite element simulation of the pseudo-static test results was carried out based on the Open Sees platform.The finite element simulation of the pseudo static test results was carried out based on the Open Sees platform.Finite element analysis model and calculation method that could be consistent with the test results were proposed.The results showed that the finite element simulation results were basically consistent with the test results,and the self-centering pier model with sacrificial components could accurately simulate the characteristics of pier shaft displacement,pier bottom angle,hysteretic curve and skeleton curve.