Retrofit Existing Frame Structures to Increase Their Economy and Sustainability in High Seismic Hazard Regions

Abstract

Featured Application: The study can be used for retrofitting frame structures to satisfy a revised seismic design code, where a building site had a low seismic hazard but now has a high seismic hazard. Abstract:The study proposes a retrofitting method with an optimum design of viscous dampers in order to improve the structural resistant capacity to earthquakes. The retrofitting method firstly uses a 2D frame model and places the viscous dampers in the structure to satisfy the performance requirements under code-specific design earthquake intensities and then performs an optimum design to increase the structural collapse-resistant capacity. The failure pattern analysis and fragility analysis show that the optimum design leads to better performance than the original frame structure. For regular structures, it is demonstrated that the optimum pattern of viscous damper placement obtained from a 2D frame model can be directly used in the retrofitting of the 3D frame model. The economic loss and repair time analyses are conducted for the retrofitted frame structure under different earthquake intensities, including the frequent earthquake, the occasional earthquake, and the rare earthquake. Although the proposed method is based on time-history analyses, it seems that the computational cost is acceptable because the 2D frame model is adopted to determine the optimum pattern of viscous damper placement; meanwhile, the owner can clearly know the economic benefits of the retrofitting under different earthquake intensities. The retrofitting also causes the frame to have reduced environmental problems (such as carbon emission) compared to the original frame in the repair process after a rare earthquake happens. Appl. Sci. 2019, 9, 5486 2 of 23 due to several aspects; e.g., the new observations from recent earthquakes, technical improvements of hazard analysis, data accumulation, and societal and economic increases.One of the issues is that a large number of existing buildings have insufficient resistant capacities to satisfy the increased design earthquake intensity. In terms of economic benefit and environmental sustainability, the best choice is to retrofit existing structures rather than demolish them and rebuild new ones. Among many retrofitting methods [4][5][6][7][8][9][10][11], the placement of viscous dampers may be one of the easy ways to improve the seismic performance of structures, because it only induces limited downtime. To date, many studies have focused on the retrofitting of structures with viscous dampers. Pekcan et al. [12] showed that the setting of the viscous damper coefficient of the story should be according to the story shear, and placements of dampers at upper stories may be not effective. Uriz and Whittaker [13] studied the effectiveness of using viscous dampers for the retrofit of a frame building before the Northridge earthquake. Silvestri and Trombetti [14] presented a parametric analysis to compare the performances offered by various systems of added viscous dampers in shear-type structures. ...

Comparative Study on Seismic Performance of Existing Building with and without Retrofitting Using Lateral Load Resisting Systems

“…This is where various innovative strategies like energy dissipation devices come into picture [1]. Different case studies of actual buildings where traditional and innovative retrofitting methods pplied were reviewed [2]. To verify the retrofitting method, a six storey building was considered and the aim was to increase the structural sustainability in an environment prone to higher seismic hazard than in the initial structural ncluded the different restrictions involved in retrofitting and choosing an optimal method which is cost effective.…”

Effectiveness of the Novel Rehabilitation Method of Seismically Damaged RC Joints Using C-FRP Ropes and Comparison with Widely Applied Method Using C-FRP Sheets—Experimental Investigation

“…Considering the abovementioned, it is clear that inexpensive, fast and long-term strengthening strategies for repairing/upgrading RC structures are urgently required, not only after destructive earthquakes, but even before they occur [4]. Retrofitting existing buildings rather than demolishing and rebuilding new ones is the best option in terms of economic gain and environmental protection [5,6]. Therefore, the investigation of strengthening and rehabilitation techniques for RC structural members that have suffered damage during an earthquake and are to be reused afterwards is a very important area of research, since both the safety of the structures and economic interests are involved [7,8].…”