Risk‐based seismic design of base‐isolated structures with single surface friction sliders

Abstract

Choosing friction pendulum isolators to avoid problems with device displacement capacity or boundary wall collision is a critical part of the seismic design of base isolation systems. This paper developed a probabilistic method to quantify the risk of failure in single friction pendulum bearing (FPB) devices. This was done by calibrating a demand-intensity model for FPBs from numerical analysis for several device property combinations. These properties encompassed the dynamic friction coefficient and effective radius of curvature-key parameters impacting these FPB devices' seismic response. Through this demand-intensity model, a closed-form and relatively simple approach to quantify the mean annual frequency of exceeding a given device displacement threshold, or risk of failure, was proposed. By applying this simplified method to several case study structures and comparing it with a more extensive assessment involving multiple stripe analysis (MSA) using hazard-consistent ground motions, the proposed simplified approach could provide very accurate estimates of displacement-based failure risk in FPB devices under the assumption of no non-linear behaviour in the superstructure. This proposed approach implies that structural engineers can now quickly assess the actual failure rates of different FPB device combinations used in practice to give a more uniform level of safety or reliability when designing and assessing FPB-isolated systems. It is also arguably much simpler, direct and accurate than currently available code-based approaches.

Exploring the site dependency of fragility functions in risk‐targeted design

“…As soon as the site characteristics during the application of these methods notably differ from the distribution of ground motions used in their developments, the consistency will begin to break down slightly. The same is also true of a recent risk‐targeted method to design friction pendulum isolators 44 or to the extension of the SPO2IDA tool to infilled frame systems 45 . While the above statements may appear to be rather critical, it is noted that these principally apply to methods that are based around using Sa ( T ) as the IM.…”

Risk‐targeted importance factors for prescriptive seismic design of critical buildings

“…As a result, despite its superiority, the adoption of the PBSD approach in design standards is rare, and a large majority of buildings worldwide continue to be designed using prescriptive force‐based standards 28 . In the last decade and a half, simplified risk‐targeted seismic design (RTSD) has been a thriving area of research for gradually introducing performance‐based design into practice 29–33 . Gkimprixis et al 34 .…”

The risk‐targeted verification model of earthquake‐induced sliding displacement of low‐rise thermally base‐insulated buildings

“…For example, Franchin et al 18 presented the risk-targeted seismic design of reinforced concrete frames. O'Reilly et al 23 presented an approach for risk-based seismic design of base-isolated structures with single surface friction sliders. Žižmond and Dolšek 20 proposed risk-targeted design procedures using linear elastic whereas Lazar et al 21 presented the procedure for risk-based design using nonlinear analysis.…”

“…presented the risk‐targeted seismic design of reinforced concrete frames. O'Reilly et al 23 . presented an approach for risk‐based seismic design of base‐isolated structures with single surface friction sliders.…”

“…Consequently, the latter of which is preferred for practical applications and is considered in the present study. Some procedures for the risk-targeted [16][17][18][19][20] and risk-based [21][22][23] design of the structures have already been proposed. For example, Franchin et al 18 presented the risk-targeted seismic design of reinforced concrete frames.…”