Details:

Creators:
Banerjee, Swagata ; Chandrasekaran, Sandhya ; Venkittaraman, Ashok
Banerjee, Swagata ; Chandrasekaran, Sandhya ; Venkittaraman, Ashok Less -
Corporate Creators:
Thomas D. Larson Pennsylvania Transportation Institute
Corporate Contributors:
United States. Dept. of Transportation. Research and Innovative Technology Administration
Subject/TRT Terms:
[+]
Before And After Studies Benefit Cost Analysis Earthquake Resistant Design Highway Bridges Jacketing (Strengthening) Optimization Reinforced Concrete Bridges Resilience Retrofitting Scour Seismicity Statistical Analysis
Publication/ Report Number:
PSU-2012-01 ; LTI 2014-11
PSU-2012-01 ; LTI 2014-11 Less -
Resource Type:
Tech Report
Geographical Coverage:
United States
Corporate Publisher:
Mid-Atlantic Universities Transportation Center
Abstract:
This study evaluated the resilience of highway bridges under the multihazard scenario of earthquake in the presence of

flood-induced scour. To mitigate losses incurred from bridge damage during extreme events, bridge retrofit strategies are

selected such that the retrofit not only enhances bridge performance, but also improves resilience of the system consisting

of these bridges. The first part of the report focuses on the enhancement of seismic resilience of bridges through retrofit. To

obtain results specific to a bridge, a reinforced concrete bridge in the Los Angeles region was analyzed. This bridge was

severely damaged during the Northridge earthquake due to shear failure of one bridge pier. A seismic vulnerability model of

the bridge was developed through finite element analysis under a suite of time histories that represent regional seismic

hazard. The obtained bridge vulnerability model was combined with appropriate loss and recovery models to calculate the

seismic resilience of the bridge. The impact of retrofit on seismic resilience was observed by applying a suitable retrofit

strategy to the bridge, assuming its undamaged condition prior to the Northridge event. A difference in resilience observed

before and after bridge retrofit signified the effectiveness of seismic retrofit. The applied retrofit technique was also found to

be cost effective through a cost-benefit analysis. A first-order, second-moment reliability analysis was performed and a

tornado diagram developed to identify major uncertain input parameters to which seismic resilience is most sensitive.

Statistical analysis of resilience obtained through random sampling of major uncertain input parameters revealed that the

uncertain nature of seismic resilience can be characterized with a normal distribution, the standard deviation of which

represents the uncertainty in seismic resilience. An optimal (with respect to cost and resilience) bridge retrofit strategy under

multihazard was obtained in the second phase of this study. A multi-objective evolutionary algorithm, namely Non-dominated

Sorting Genetic Algorithm II, was used. Application of this algorithm was demonstrated by retrofitting a bridge with column

jackets and evaluating bridge resilience under the multihazard effect of earthquake and flood-induced scour. Three different

retrofit materials—steel, carbon fiber, and glass fiber composites—were used. Required jacket thickness and cost of

jacketing for each material differed to achieve the same level of resilience. Results from the optimization, called Pareto-optimal set, include solutions that are distinct from each other in terms of associated cost, contribution to resilience

enhancement, and values of design parameters. This optimal set offers the best search results based on selected materials

and design configurations for jackets.


Format:
PDF
Funding:
DTRT12-G-UTC03
Collection(s):
US Transportation Collection University Transportation Centers
Main Document Checksum:
[+]
urn:sha256:3d09794268823bb9daf60477bf45498839c226080a1da9e44e186c15167782ea
Download URL:
https://rosap.ntl.bts.gov/view/dot/27476/dot_27476_DS1.pdf
File Type:

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