A Complementary Approach to Condition Assessment of Highway Bridges Using a Quantitative Index Measure

Abstract

This paper discusses the preliminary stages for the development of a quantitative based performance index measure that will allow inspection engineers to complement existing qualitative inspection protocols. This proposed method seeks to implement select experimental load testing and rating parameters that are commonly computed by department of transportation (DOT) agencies on a selected bridge basis. The performance index measurement was developed to be a function of two particular variables, the neutral axis of bending and transverse load distribution factor. These parameters were selected as they are both independent of the vehicle weight used for exciting the bridge. This is significant in that it would not require inspection engineers to use the same vehicle loading each time for inspection. The performance index serves in a similar manor to that of the condition rating used today only the data will be gathered from strain sensors instead of being based solely on visual observations. The initial stages of the performance index are developed by calibrating the ratio of neutral axis to distribution factor as well as the load rating for the various steel girders of the 3- span stringer/multi-girder bridge tested. This tool would serve to complement existing inspection protocols as an additional index based on quantitative data as opposed to visual inspection findings. While still in the early stages of development, this assessment tool looks to help close a piece of the gap in the need for improved condition assessment methods.