Research on seismic absorption of high-speed railway segmental assembled round-end hollow pier with low yield point steel connection buckle

The research aims to enhance the seismic safety of the segmental assembled round end hollow pier (SAREHP) of high-speed railway in high intensity seismic regions and ensure the repairability of the pier after earthquake. A low yield point steel connection buckle (LYPSCB), which is easy to be installed and to be replaced after earthquake damage, was proposed as a new seismic absorption measure for the pier, and the seismic absorption effect of the LYPSCB was deeply studied. Firstly, the nonlinear numerical model of the SAREHP with energy dissipation bar (SAREHP-EDB) was established according to the pseudo-static test results of the pier completed. Based on the numerical model of the SAREHP-EDB, the SAREHP with the LYPSCB (SAREHP-LYPSCB) was established and corrected. Subsequently, the influence of the LYPSCB on the hysteretic behavior of the SAREHP was studied, and the hysteretic behavior of the SAREHP-LYPSCB was comprehensively compared with a reference to the SAREHP-EDB. Furthermore, considering the far-field seismic wave and the near-field seismic wave with or without pulse, the seismic absorption effect of the LYPSCB was revealed through dynamic time history analysis method. The research results indicated that, by increasing the section contribution rate of the LYPSCB, the horizontal resistance, loading and unloading stiffness as well as energy dissipation capacity of the SAREHP-LYPSCB are significantly improved. However, the residual displacement of the pier is also indirectly increased. Therefore, it is suggested that the section contribution rate of the LYPSCB is controlled and designed in combination with the seismic target displacement and self-centering capacity demand of pier. The hysteretic behavior of the SAREHP-LYPSCB is better than that of the SAREHP-EDB, which indicated that the LYPSCB possesses better seismic absorption effect. Note that the seismic absorption effect of the LYPSCB is more obvious in resisting strong earthquake, in which the seismic absorption rate can reach 80 %. The near-field pulse seismic wave has the greatest impact on the seismic response of the SAREHP-LYPSCB compared with other types of seismic wave, which should be paid special attention.