Evaluating the impact of fluid viscous dampers on the seismic collapse and loss assessment of Chilean RC dual wall-frame buildings

Abstract

During the 2010 Mw 8.8 earthquake in Chile, with the exception of a few collapse occurrences, reinforced concrete (RC) buildings generally experienced minor structural damage. Nevertheless, the event caused significant economic losses partly due to damage to their nonstructural building components and contents. This observation suggests a need for higher levels of resilience in buildings, which might be achieved by incorporating seismic protection systems, such as fluid viscous dampers (FVDs), into the structural system. This study assesses the effect of FVDs on the seismic performance of code-conforming high-rise RC dual wall-frame office buildings. As a case study, a 16-story archetype building representative of the Chilean state of design and construction practice was selected. Two cases were analyzed: i) the archetype without dampers (i.e., conventional design), and ii) the same archetype equipped with supplemental FVDs. The archetypes were examined considering the latest developments in performance-based earthquake engineering. Three-dimensional nonlinear models, developed in Perform-3D, were subjected to incremental dynamic analyses using a set of hazard-consistent Chilean subduction ground motions to evaluate the collapse fragility of the case study buildings. Additionally, a loss assessment was carried out using the FEMA P-58 methodology at four distinct hazard levels with return periods of 72, 475, 2475, and 4975 years. The convenience of the performance improvement strategy was quantitively evaluated in terms of reduction in collapse risk and expected direct economic losses. The results revealed that the archetype equipped with FVDs exhibits a higher level of collapse capacity and smaller levels of economic losses despite higher initial construction costs. The 50-year probability of collapse was almost halved when the dampers were incorporated. Similarly, reductions in earthquake-induced repair costs were on the order of ~50% with respect to those from a conventional design. Greater cost decreases were observed under extreme shaking intensities (e.g., 2475 and 4975-year return periods) than under more frequent earthquakes (i.e., 72 and 475-year return periods).