Dissertation/Thesis Abstract

Development of Low Seismic Damage Structural Systems
by Nema, Arpit, Ph.D., University of California, San Diego, 2018, 248; 10975651
Abstract (Summary)

Modern society requires enhanced seismic performance from its structures that is beyond simple life-safety requirements, which has been the main design objective in the 20th and early 21st centuries. Multiple approaches to low-damage seismic structures have been developed towards the end of the last century, one of which is the hybrid re-centering element approach studied experimentally and analytically in this work.

The first half of this dissertation focuses on the application of re-centering behavior to structural walls in multi-story structures. A four story, half scale structure with an eccentric arrangement of structural walls was tested dynamically at the UC San Diego Large High-Performance Outdoor Shake Table (LHPOST). The test also incorporated a new low damage gravity column concept. Results from the test provided valuable information about the two-dimensional seismic behavior of multi-story structures incorporating hybrid-re-centering structural walls.

An analytical model was developed for modeling the behavior of re-centering structural walls and calibrated as a part of a full three-dimensional model of the test specimen analyzed under a sequential application of the measured excitation history. An analytical model for a re-centering system applicable to moment frames was also developed and calibrated against experimental results from a previous study undertaken at UC San Diego. As a conclusion, the two models were incorporated into an analytical model of a thirteen-story structure with different lateral force resisting systems in orthogonal directions which was then studied using seven historic ground motions following the guidelines of ASCE/SEI 7-10 (2010).

The second half of the dissertation focuses on re-centering systems in bridge structures. A 35% scale, bridge bent with two hybrid re-centering columns was tested dynamically at the UC Berkeley PEER Shaking table. The specimen was constructed using a new socket connection based Accelerated Bridge Construction technique. Precast construction was utilized for the three major bent components: the columns, the bent-cap and the foundation, which were then assembled at the test facility. Results from the test were used to calibrate the dynamic behavior of a computational model developed for the analysis of re-centering bridge columns. The proposed model improves upon earlier models resulting in significantly faster analysis speeds, allowing for the modeling of complete bridge systems in reasonable time-frames. Finally, the multi-column bridge bent model was incorporated into a comprehensive three-dimensional model of an existing bridge and used for studying the bridge response under different configurations of prestress force capacities and energy dissipation capacities.

Indexing (document details)
Advisor: Restrepo, José I.
Commitee: Conte, Joel P., Loh, Kenneth, Rao, Bhaskar, Uang, Chia-Ming
School: University of California, San Diego
Department: Structural Engineering
School Location: United States -- California
Source: DAI-B 80/05(E), Dissertation Abstracts International
Subjects: Engineering, Civil engineering
Keywords: Computer modeling, Low damage bridge, Low damage gravity column, Low damage structure, Re-centering bridge, Re-centering structure
Publication Number: 10975651
ISBN: 978-0-438-75817-9
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