Closure to “Application of a Nonstandard Explicit Integration to Solve Green and Ampt Infiltration Equation” by Damodhara R. Mailapalli, Wesley W. Wallender, Rajendra Singh, and Narendra S. RaghuwanshiHybrid Simulation of Small-Scale Steel Braced Frame Subjected to Fire and Fire Following Earthquake

Abstract

Various studies have demonstrated the effectiveness of employing different fire protection strategies in reducing damage and losses associated with fire events in conventional buildings. However, studies geared toward understanding structural vulnerability due to fire following an earthquake, as a result of failure of the fire protection systems in a seismic event, are scarce. This study investigated the fire performance of a steel structure in two different scenarios: without a prior earthquake event, and with residual deformation from an earthquake event. To understand the fire performance of a structure that has been subjected to an earthquake, three different levels of seismic intensities were considered, represented by interstory drift ratios. To realistically simulate the structural behavior when subjected to elevated temperature, a hybrid fire simulation method was adopted in which a column was modeled physically and subjected to temperature and mechanical loads, whereas the remainder of the structure was modeled numerically. Due to laboratory constraints, a small-scale structure was used to illustrate the developed framework and demonstrate the potential effect of an earthquake on fire performance of a building. The test results showed that smaller axial deformation but larger force developed in the physical column when it was not subjected to an interstory drift prior to the fire event. On the other hand, columns with higher levels of residual interstory drift experienced larger vertical deformation and smaller axial force, and failed earlier than those with lower interstory drift. Based on the preliminary findings from this study, further investigations are recommended to quantify the effect of interstory drifts from seismic events on fire vulnerability of various types and configurations of structural steel systems. Full-scale hybrid simulations can serve as a valuable tool to gain insight into the behavior of these various systems.