Thesis
Seismic retrofit of cruciform-shaped columns in the Aurora Avenue Bridge using FRP wrapping
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/100698
Abstract
One of the major problems associated with the seismic response of older reinforced concrete bridges has been brittle shear failure of inadequately reinforced bridge columns. The study reported in this thesis consisted of an experimental investigation of cruciform-shaped column specimens representative of columns in the SR-99 Aurora Avenue Bridge located in Seattle, Washington. The primary goal was to evaluate the effectiveness of fiber reinforced polymer (FRP) composite wrapping for enhancing the seismic shear strength of the columns. Five large-scale cruciform-shaped columns were subjected to increasing levels of cyclic displacements representative of seismic loading. Parameters varied in the tests included the presence or absence of FRP wrapping, presence or absence of reentrant corner anchorage, type of reentrant corner anchorage used, and the presence or absence of plastic hinge zone confinement. Two unretrofitted specimens were tested to examine the performance of the as-built columns with deficient transverse reinforcement, and three specimens were tested after retrofitting with carbon fiber FRP composite wrapping. The performance of the tested specimens was evaluated based on failure mode, peak displacement levels attained before failure, and hysteretic behavior. The as-built column specimens experienced a brittle shear failure at limited displacement levels. Retrofitting using FRP wrapping but without reentrant corner anchorage slightly improved the seismic performance of the column, but the specimen still experienced a brittle shear failure at only slightly larger displacement levels than those attained in the as-built specimens. Column specimens retrofitted with FRP wrapping and reentrant corner anchorage showed significant improvement in the seismic performance with enhanced strength, energy and ductility capacities. Evaluation of the FRP jacket stresses indicated that the FRP jacket remained elastic under large cyclic shear forces and provided the required shear strength enhancement. To prevent bulging in the plastic hinge region, one specimen was retrofitted with a grout filled steel collar throughout the plastic hinge length. Design and detailing guidelines for retrofitting cruciform-shaped columns are proposed. The guidelines include jacket thicknesses and reentrant corner anchorage required to prevent shear failure in the column.
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Details
- Title
- Seismic retrofit of cruciform-shaped columns in the Aurora Avenue Bridge using FRP wrapping
- Creators
- Brian John Walkenhauer
- Contributors
- David I. McLean (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525178001842
- Language
- English
- Resource Type
- Thesis