American Society of Civil Engineers

Deterioration Rates of Typical Bridge Elements in New York

by A. K. Agrawal, (corresponding author), M.ASCE, (Professor, Dept. of Civil Engineering, City College of New York, New York, NY 10031 E-mail:, A. Kawaguchi, (Associate Professor, Dept. of Computer Science, City College of New York, New York, NY 10031. E-mail:, and Z. Chen, (Graduate student, Dept. of Computer Science, Graduate Center of CUNY, New York, NY 10016)

Journal of Bridge Engineering, Vol. 15, No. 4, July/August 2010, pp. 419-429, (doi:

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Document type: Journal Paper
Special Issue: Bridge Inspection and Evaluation
Abstract: The New York State Department of Transportation (NYSDOT) maintains an inventory of over 17,000 highway bridges across the state. These bridges are inspected biennially or more often as necessary. Bridge inspectors are required to assign a condition rating for up to 47 structural elements of each bridge, including 25 components of each span of a bridge, in addition to the general components common to all bridges. The bridge condition rating scale ranges from 7 to 1; 7 being new and 1 being in failed condition. These condition ratings may be used to calculate the deterioration rates for each bridge element, while considering the effects of key factors, such as the bridge material type, on the deterioration rates. This paper describes an approach based on the Weibull distribution to calculate the deterioration rates of typical bridge elements in New York State using historical bridge inspection data and compares the results with those using the traditionally used Markov chains approach. It is observed that the Weibull-based approach performs better in terms of the observed conditions than the traditionally used Markov chains approach for developing deterioration curves for different bridge elements. Both Markov chains and Weibull-based approaches have been incorporated into a computer program that generates the deterioration curves for specific bridge elements based on historical NYSDOT bridge inspection data dating back to 1981. Case studies on the deterioration rates of various bridge elements in New York State are presented to demonstrate the two approaches. The case studies show that the element deterioration rate information can be used to determine the expected service life of different bridge elements under a variety of external factors. This information is extremely valuable for making bridge management decisions. Based on the Weibull-based approach, the deterioration rates for typical bridge elements in New York State have been presented.

ASCE Subject Headings:
Bridge inspection
Highway bridges
Markov process
New York

Author Keywords:
Deterioration rates
Markov chain method
Weibull-based method
Bridge inspection data
Condition ratings