Temperature Monitoring and Response of Deck-Extension Side-by-Side Box Girder Bridges

To enhance the durability of side-by-side box girder bridges, a common source of maintenance issues can be eliminated using the jointless bridge concept. Accurate estimation of the average effective bridge temperature range is a key issue. A deck-extension bridge containing side-by-side box girders was chosen as case study. The temperature distribution on the bridge cross section and the longitudinal thermal movement of the superstructure were monitored. Finite-element models of the bridge superstructure were developed, which indicated close agreement with measured temperature responses. The average effective temperature of girder cross sections could accurately predict the longitudinal thermal movement of the superstructure. The highest and lowest average effective bridge temperatures for side-by-side box girders were estimated for 12 cities in 4 climatic regions in China under historically extreme temperature conditions. For most cities, the difference between the highest and lowest average effective bridge temperatures exceeded the design temperature range. The Chinese-code design procedures may overestimate the allowable length of deck-extension bridges, because the code underpredicts the change in the average effective bridge temperature.