Field Study of an Integral Backwall Bridge: Final Report

About the report:

Integral bridges offer reduced maintenance expenditures, primarily due to the elimination of deck expansion joints. The design of an integral bridge, however, is complicated by the soil-structure interaction associated with thermal movements. It has been widely recognized that more data on the actual stresses and their distribution within the structure are needed for an optimal design. Current integral designs are often conservative and based on empirical values. This study is an analysis of an integral backwall bridge which was instrumented during construction and monitored for 2.5 years. Field instrumentation included strain gages, temperature probes and earth pressure cells. Data were collected continuously using electronic dataloggers. The results demonstrate a satisfactory performance of the structure; however, some maintenance problems associated with excessive approach settlement were observed. Soil pressures exerted on the back of the integral backwall showed significant daily variation as a result of ambient air temperature fluctuation.

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