Structural Review of a Bridge for Condition Assessment

The cost of performing a thorough bridge condition assessment is prohibitive, as it requires the installation of sensors, weigh-in-motion bridge facilities, load tests, destructive and non-destructive testing, and monitoring of the data they provide to estimate the bridge's durability. This study establishes the applicability of the structural review approach and demonstrates how it can be effectively utilized for assessing bridge conditions, particularly in developing countries such as Nigeria. Bridge inspection was performed on the Benin-Sagamu Overpass bridge to demonstrate this approach and condition rating of key bridge elements. Numerical appraisal equations were applied to the findings of the bridge inspection, which quantified the risks associated with the structure and its reliability. The decision on whether to embark on an intensive assessment scheme or not, and to determine the extent of assessment required if necessary, was arrived at based on the risk and reliability indices. The structural review tool proves to be less expensive and effective as the results it presents, reflect the actual physical conditions of the bridge. The cost of using the structural review tool for an assessment is only about 4% of the cost associated with a complete bridge structural assessment. The value of reliability deduced, which is 11.028, reflects the system reliability of the bridge, while the risk score of 333.33 reflects all the risks directly associated with the bridge and is a reliable tool for decision-making. The findings from the review on the bridge suggest there is no need for an inspection for assessment or a full-scale investigation for the durability of the bridge, and that the best decision regarding the bridge is to allow for another review after a certain number of years. It is recommended that the bridge authority perform a well-documented Principal Inspection on the facility for reference purposes in future reviews, and that this review tool be adopted to assess and document bridges across Nigeria in order to establish a database for the current condition of all bridges and start a bridge management program.