05-09-2014, 03:10 PM
Structural Response and Cost Characterization of Bridge Construction using Seismic Performance Enhancement Strategies
Author: Ady Aviram Traubita | Size: 12.3 MB | Format: PDF | Quality: Unspecified | Publisher: University of California, Berkeley | Year: 2009 | pages: 302
The improved seismic performance and cost-effectiveness of two innovative performance-enhancement technologies in typical reinforced concrete bridge construction in
California were assessed in an analytical and experimental study. The technologies considered were lead rubber bearing isolators located underneath the superstructure and fiber-reinforced
concrete for the construction of bridge piers. A typical five-span, single column-bent reinforced concrete overpass bridge was redesigned using the two strategies and modeled in OpenSees finite element program. Two alternative designs of the isolated bridge were considered; one with columns designed to remain elastic and the other such that minor yielding occurs in the columns (maximum displacement
ductility demand of 2). The analytical model of the fiber-reinforced concrete bridge columns was calibrated using the results from two bidirectional cyclic tests on approximately ¼-scale circular cantilever column specimens constructed using concrete with a 1.5% volume fraction of highstrength hooked steel fibers, relaxed transverse reinforcement, and two different longitudinal reinforcement details for the plastic hinge zone. Pushover and nonlinear time history analyses using 140 ground motions were carried out for the different bridge systems. The PEER performance-based earthquake engineering
methodology was used to compute the post-earthquake repair cost and repair time of the bridges. Fragility curves displaying the probability of exceeding a specific repair cost and repair time
thresholds were developed. The total cost of the bridges included the cost of new construction and post-earthquake repair cost required for a 75 year design life of the structures. The intensitydependent repair time model for the different bridges was computed in terms of crew working days representing repair efforts. A financial analysis was performed that accounted for a wide range of discount rates and confidence intervals in the estimation of the mean annual postearthquake
repair cost.
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