Project Description

According to the U.S. Department of Transportation, as of December 2008, of the 600,905 bridges 72,868 (12.1%) were categorized as structurally deficient (SD) and 89,024 (14.8%) were categorized as functionally obsolete (FO). Despite healthy economy during the period 1995? 2005, the numbers of SD and FO bridges were on the rise. It is very clear that our bridge evaluation and maintenance policies are not working efficiently. The high numbers of SD and FO bridges should not be allowed to continue to rise. Given the current state of the US economy, smarter bridge management policies should be adopted, as we cannot afford the high cost of proper maintenance of our huge transportation civil infrastructure.

Regardless of age and condition, current practice requires bi?annual inspection of highway bridges, which results in costly inspection caused by un?necessary frequent inspections of newer bridges and lack of frequent inspection of older bridges. There is a need for more rational approach for setting bridge inspection frequency based on safety, condition, design, age of the structure, and engineering judgment. In addition, there should be a clearer differentiation between maintenance and repair. The cost of major repairs is much higher than timely preventive maintenance measures. There are many cases where minor maintenance activity is delayed until it becomes a structural deficiency, which resulted in high number of bridges categorized as structurally deficient.

Practical experience coupled with non?destructive test (NDT) data produce good assessment of bridge condition. The question is how to utilize NDT data to develop a cost?effective maintenance policy for our bridges. NDT data should not only be used for assessing current condition of bridges, but also to predict its deterioration rate and its future maintenance needs. NDT data of the likelihood of corrosion in a bridge component is a very good indication of its future deterioration rate in the following few years. If implemented, low cost maintenance measures would stop or slow the deterioration rate resulting in lower maintenance cost over the service life of the bridge.

This paper will present smart use of NDT data to predict the near future service life of concrete bridge components, and its utilization for cost?effective maintenance policy, in a limited financial resources environment. The impact of this study will enhance the followings: (1) development of better rational for setting maintenance frequency based on condition, (2) development of low?cost maintenance measures for better control of deterioration rate, (3) understanding of financial consequences of delayed maintenance, and (4) reduction of the number of structurally deficient bridges.