Investigate Multilevel Seismic Responses of Base Isolated Tall Building Using Triple Friction Pendulum Bearing


Abstract eng:
The global trend towards urbanization has led to unprecedented numbers of people working and living in tall buildings. For cities located in regions susceptible to strong earthquake ground shaking, seismic design of these costly, high-occupancy tall building is always a critical concern for engineers and general public. As a minimum requirement for structural safety, seismic design code for general structure is not enough for tall building. Performance design criteria has been proposed for tall buildings in order to achieve not only safety but also seismic resiliency so that they can continue to be functional with lower repair cost and shorter business downtime following a moderate earthquake. To achieve seismic resiliency in design, new structural systems and energy dissipation device have been studied and implemented. One efficient approach to enhance seismic performance is using seismic isolation. In this paper, a preliminary investigation of seismic responses for a 30-story tall, base isolated steel moment-resisting frame building is conducted by numerical analysis in Open System for Earthquake Engineering Simulation (OpenSEES). Global responses are evaluated in terms of several key engineering demand parameters (EDPs). Particular attention is paid to achieving improved performance by fine tuning the isolator properties under multi-level seismic events. While tuning can be done for many types of isolation bearings, the Triple Pendulum Friction Bearing (TPFB) is used in the study as it allows a wide variety of hysteretic characteristics to be obtained, which can be readily related to physical and mechanical characteristics of the bearing. Parametric studies have been conducted to investigate the sensitivity of global EDPs to different key design parameters of isolator as well as superstructure under different levels of seismic events. Based on numerical analysis results, the study first evaluates the effectiveness of using base isolation with different isolation periods to reduce seismic responses for a tall building. By comparing global responses from sensitivity studies on different design parameters, the study concludes that the upper structure responses of isolated tall building are mainly affected by radius of sliding surfaces, smaller radius results into better reduction of responses but with larger bearing deformation as trade off. Floor acceleration responses are sensitive to friction coefficients of sliding surfaces, especially for initial friction coefficient. Small initial friction coefficient not only reduces floor acceleration but improves the responses under frequent earthquake event. Large third friction coefficient is beneficial to control the displacement demand of bearing especially under rare event. The study also shows the advantages of TFPB comparing to Single Friction Pendulum Bearing (SFPB) when bearing deformation is small. In addition, the study reveals shorter fundamental period of superstructure leads to better efficiency of base isolation, while the deflection shape of the tall building is insignificant to the responses.

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Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 3023.:
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