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Accession Number PB2014-100859
Title Seismic Design and Performance of Bridges with Columns on Rocking Foundations.
Publication Date Sep 2013
Media Count 103p
Personal Author G. Antonellis M. Panagiotou
Abstract Traditional seismic design of bridges includes ductile details that allow bridges to develop substantial inelastic deformations when subjected to severe earthquakes. While bridges designed in this manner may be safe from collapse following an earthquake, they are susceptible to considerable damage and permanent lateral displacements that can impair traffic flow and necessitate costly and time-consuming inspections and repairs (perhaps even demolition). Nowadays, as an alternative design strategy, bridges with columns supported on rocking foundations are designed to undergo large deformations but sustain far less damage and can recenter after large earthquakes. The numerical study presented herein investigates the seismic response of two bridges subjected to two sets of forty ground motions each, one consisting of pulse-type near-fault ground motions and another containing a mix of near- and far-fault ground motions. Three design strategies were considered for each of the two bridges. The first design is based on current common practice, which expects flexural plastic hinging in the columns. The other two designs use rocking shallow and pile foundations, respectively. The columns in the bridge with the rocking foundation are designed to remain elastic while also accounting for the effect of framing between the columns, the deck, and the abutments. The bridges with rocking foundations consider several different cases in terms of size of columns, bearings, and expansion joints at the abutments. Each bridge model is subjected to the two sets of ground motions using two horizontal components for each ground motion. The numerical results show that lateral drift similar to that experienced by fixed-base bridges is possible in the bridges with rocking pile foundations, with essentially an elastic response in the columns. A comparison of the seismic performance of the bridges in terms of post-earthquake repair cost is conducted using an existing performance evaluation framework based on the Pacific Earthquake Engineering Research Centers performance-based earthquake engineering method. Existing damage models for the columns, bearings, and shear keys are used, while a new damage model of rocking shallow foundations is developed. The structural components are classified in different performance groups, with discrete damage states and repair methods.
Keywords Bridge abutments
Bridge foundations
Bridges
Columns(Supports)
Damage assessment
Deformation
Design methods
Earthquakes
Ground motion
Joints
Performance evaluation
Repair
Seismic effects


 
Source Agency National Science Foundation
NTIS Subject Category 50A - Highway Engineering
89D - Structural Analyses
Corporate Author California Univ., Berkeley. Dept. of Civil and Environmental Engineering.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1403
Contract Number N/A

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