Thesis
The effects of long-duration earthquakes on concrete bridges with poorly confined columns
Washington State University
Master of Science (MS), Washington State University
2004
Handle:
https://hdl.handle.net/2376/247
Abstract
The main goals of this research were to implement a mathematical damage model for older, poorly confined, concrete bridge columns into the computer program WSU-NEABS and then evaluate bridge response to long-duration earthquakes. Two actual highway bridges were modeled with finite element spine models and analyzed with this modified version of the nonlinear analysis program. The analyses were done in two stages, the first of which included analyzing the bridges subjected to a suite of ten earthquakes. The suite of earthquakes incorporated short and long-duration events. Results from the analyses were used to predict the response of the bridges and determine if long-duration earthquakes significantly change their response. The second stage of the analyses involved a parametric study in which the soil stiffness at the column bases and abutments was varied. In each case, the response of the bridge was then compared to that of the original model in the first stage. The results were also evaluated to determine if long-duration earthquakes were more damaging with these variations. A simplified bent model was also constructed to represent the center pier of the bridge with the most critical response. This model was then analyzed to determine if a bent model can accurately model the response of the bridge, or if the entire bridge model is necessary. The results from the analyses show that neither the short or long-duration events will cause major damage in the bridge columns for the bridges considered. However, the analyses do show that the bridges are predicted to have issues with pounding and possible failure of the bearing pads. The second stage of the analyses shows that the current modeling techniques used by the Washington Department of Transportation, in which rollers are applied at the abutments and the column bases are fixed, predicts more damage to the bridge columns compared to results from more refined foundation models. Thus, the present techniques are a conservative practice for the bridge columns. However, models based on these techniques under predict the pounding at the expansion joints and possible failure of the bearing pads, thus representing an unconservative approach these elements in the bridge.
Metrics
5 File views/ downloads
17 Record Views
Details
- Title
- The effects of long-duration earthquakes on concrete bridges with poorly confined columns
- Creators
- Theron James Thompson
- Contributors
- William F. Cofer (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
- 99900525123101842
- Language
- English
- Resource Type
- Thesis