دانلود رایگان مقاله انگلیسی بهینه سازی احتمالی مبتنی بر سیستم میراگر ویسکوز سیال مجهز شده در پل کابلی - Sage 2018

Abstract

This study presents a methodology to evaluate the optimal parameters of fluid viscous damper for cable-stayed bridges using the system-level fragility assessment approach. Instead of investigating the impact of different isolation devices on the component’s vulnerability separately, this study focuses on evaluating the optimal parameters of fluid viscous damper to achieve the best overall performance of cable-stayed bridge as a system. Numerical model of a cable-stayed bridge with the most common configuration in China is established using OpenSEES that can account for their nonlinear response and uncertainty treatment. A joint probabilistic seismic demand model and Monte Carlo simulation are employed to obtain the system fragility of cable-stayed bridges by accounting for the contribution of multicomponents to the global damage state. The system-level fragility curves and component fragility curves are compared before and after the application of fluid viscous damper with different parameters. The results indicate that a given parameter of the fluid viscous damper may have a negative impact on some components, yet lead to a better performance of the bridge as a system. Thus, in order to obtain comprehensive knowledge of bridge performance and derive the accurate optimal parameters of fluid viscous damper, it is necessary to consider the fragility based on bridge system.

Conclusion

Seismic retrofit measures tend to focus on individual component response, less research has been carried out on the cable-stayed bridge performance as a system, and the optimal parameters of retrofit devices have not been addressed in the literature. This study presents a methodology to evaluate the optimal parameters of FVD for cable-stayed bridges using the system-level fragility function. JPSDM and Monte Carlo simulation are employed to obtain the system fragility of cablestayed bridges by accounting for the contribution of multi components to the global damage state. Optimal parameters of FVD are derived by directly evaluating the system-level fragility curves of the cable-stayed bridge equipped with these given FVD. A case study bridge, Polonggou cable-stayed bridge, retrofit with varied FVD is employed to exemplify the methodology. Details of the numerical modeling include nonlinear analysis, the uncertainty treatment, limit state capacities, contribution of critical components to the bridge performance as a system, and so on. For illustration purposes, component fragility curves are developed, which indicate that retrofit measures alters the relative vulnerability of the different components. The system-level fragility curves as well as component fragility curves are compared before and after the application of FVD with different parameters. The results indicate that a given parameter of the FVD may have a positive impact on some components, yet lead to a worse performance of the bridge as a system. Thus, in order to obtain comprehensive insight of bridge performance and derive the accurate optimal parameters of FVD, it is necessary to consider the fragility based on bridge system.