Utilizing Remote Sensing to Assess the Implication of Tall Building Performance on the Resilience of Urban Centers

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Tall buildings have become a staple of central business districts in the United States and other parts of the world, reflecting the intersection of increased urbanization with the constraints of limited land space. Recent advancements in computer modeling and performance-based engineering are enabling improved scientific assessment of the expected seismic performance of tall buildings in terms of stakeholder-driven metrics, such as the cost to repair damage from future earthquakes. However, these methodologies are based on the notion of the building as "an island," where seismic impacts are constrained within its footprint. However, recent earthquakes that have occurred around the world have highlighted the critical role of building performance in minimizing the impact on community functionality. This research aims to address this fundamental limitation by investigating and applying new methods to assess the impact of tall building performance on the resilience of dense urban centers, using downtown Los Angeles as a test bed. Los Angeles is selected due to the density of tall buildings, both old and new, existence of the only mandatory seismic instrumentation program in a U.S. city, and recent focus on resiliency by city government officials. An educational and outreach program will be established to create new learning modules for undergraduate students, which provide an appreciation of the critical relationship between the response of buildings to extreme events and the functionality of the communities they serve. The research program will include active participation from undergraduate and graduate students, local building officials, and researchers and practitioners with interests in performance assessment of tall buildings, application of sensor networks for monitoring and decision making, and development of local, regional, and national standards, guidelines, and codes. A primary research goal is to provide a framework that can be used in other urban centers in the U.S. This research entails three main tasks: (1) investigate how to model and assess the seismic performance of tall buildings by using and enhancing the only mandatory seismic instrumentation program for buildings that exists in the U.S. in the City of Los Angeles, (2) develop a framework that enables the study of the impact of tall buildings on the resilience of urban clusters by using Los Angeles as a test bed, and (3) create tools that enhance data use and visualization, creating opportunities for collaboration among scientists, engineers, social scientists, and policy makers. The research program will improve Los Angeles' standing as a field laboratory, which, after the occurrence of a large earthquake event, in addition to facilitating a rapid assessment of damage, will generate valuable building response data that cannot be obtained from reduced-scale experiments of idealized structures. Alternative and novel sensors will be used to capture important building responses to enable better performance assessment. Structural models will also be developed with advanced characterization of nonlinear behavior and earthquake ground motions. These models will be used to generate engineering demand parameters for the resilience-based assessment, which includes a probabilistic multi-limit state assessment of performance and quantifying the temporal evolution of the building's functionality following an earthquake. The research program tackles an important and challenging problem that will advance the ability to model and design tall buildings, taking into account the impact of their performance on urban resilience. Technology transfer will include active participation of local building officials and interactions with researchers and practicing engineers in the U.S. and abroad.