Bridges Designed for Minimum Maintenance, TR-791, 2025

(2025) Bridges Designed for Minimum Maintenance, TR-791, 2025. Transportation, Department of

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Abstract

Service-life based designs of highway bridges have gained significant interest from state DOTs in recent years. The primary purpose of these efforts is to provide durability-based designs for bridges and bridge elements that require minimal maintenance during the targeted service life of the structure. This is achieved by defining different target service lives for bridge design with the assumption that a longer target service life will result in a longer period with no or minimal maintenance. While the importance of durability-based design is highlighted in the report, which aims to achieve varying levels of target service lives that change based on the importance or the criticality of the bridge, the study acknowledges that most common bridges could be replaced due to functional improvements rather than reaching the end of their service life. Target service lives of 75 years (Normal), 100 years (Enhanced), and 125 years (Maximum) are considered in this report. The study focuses on identifying common types of bridge deterioration and maintenance activities, developing design recommendations suited to various traffic conditions and exposures, and validating the performance and cost-effectiveness of these designs through service life analysis. The report also discusses the challenges of predicting long-term degradation mechanisms and exposure conditions, and the importance of preventive maintenance strategies to prolong bridge life. Practical recommendations are presented for the considered bridge elements to achieve the different target service lives using economical design considerations. The immediate benefit of this research is implementing cost-effective bridge designs that require little to no maintenance, thereby reducing long-term costs and improving the overall performance of the transportation system in Iowa. The findings of this study could also be used by Iowa DOT to develop a guide for service life design of Iowa bridges.