Dissertation/Thesis Abstract

Seismic Assessment of Bridges with Hybrid Sliding-Rocking Columns
by Valigura, Jakub, Ph.D., University of Colorado at Boulder, 2019, 289; 22615753
Abstract (Summary)

Many U.S. bridges will require upgrade or replacement in following years. This situation is even more acute in high seismic regions where bridges may also need seismic retrofit. This effort requires large investments for new construction, but also affects the local economy with construction impacts, including traffic delays/detours. The term “accelerated bridge construction” refers to design and construction techniques that aim to lower the economic impacts of bridge construction through speedier on-site construction. This dissertation focuses on one ABC technology, bridges with hybrid sliding-rocking (HSR) columns. These columns combine precast concrete segments with internal unbonded post-tensioning. HSR column response exhibits both joint sliding, providing energy dissipation with low damage, and joint rocking, providing self-centering capabilities.

This dissertation compares the life-cycle costs of bridges with HSR columns with bridges with conventional cast-in-place columns in high seismic areas. These life-cycle costs include the costs of constructing both types of bridges, considering both direct construction costs and costs associated with construction time and traffic impacts, as well as the costs of repairing earthquake damage. To do so, the dissertation develops the methods and data needed to make this assessment. First, the seismic repair costs of bridges with conventional columns are examined. It then studies damage states and repair strategies for HSR columns. The study concludes by evaluating the life-cycle costs of the two bridge design strategies.

Chapters 2 and 3 show that for conventional bridges, different seismic column repair methods result in very similar initial investment, but can provide significantly different post-repair performance. Chapter 4 conducts cyclic lateral tests of a HSR column, confirming its superior seismic behavior to conventional columns, defining damage states, and identifying and testing repair strategies. Chapter 5 compares life-cycle assessments of bridges with conventional and HSR columns. The results show that the upfront construction costs are similar, but construction time is reduced when using HSR columns; earthquake repairs are generally less for the HSR columns. In total, the bridges with HSR column have economic benefits; the extent of the benefits are a function of bridge geometry, traffic demands and seismic hazard.

Indexing (document details)
Advisor: Liel, Abbie B., Sideris, Petros
Commitee: Porter, Keith, Dashti, Shideh, Padgett, Jamie
School: University of Colorado at Boulder
Department: Civil, Environmental, and Architectural Engineering
School Location: United States -- Colorado
Source: DAI-B 81/6(E), Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Civil engineering, Engineering
Keywords: Accelerated bridge construction, Bridge repair, Cost assessment, Performance-based earthquake engineering, Post-repair performance
Publication Number: 22615753
ISBN: 9781392764923
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