Temperature effects on cable stayed bridge using health monitoring system: a case study

Abstract

The Zhanjiang Bay Bridge, located in an inner gulf of South China, is a cable stayed bridge with a main span of 480 m. An analysis on the thermal effects experienced by the bridge is presented according to a health monitoring system (HMS) that began operation in 2006. The parameters studied in the analysis include thermal time lags and gradients of the steel box girder, concrete tower, and stayed cables, as well as displacements at center span and tops of the towers. Among the findings, temperature gradient in the steel girder was larger than the design specification, concrete temperature lagged significantly behind ambient air, and stayed cable temperatures were between those of ambient air and concrete. Additional findings were obtained by comparing the measured data to values calculated using a finite element model. The comparison made it possible to approximate the unmeasured thermal gradient on the surface of the towers, and to determine that an expansion joint was likely jammed and contributing to the bridge's asymmetrical displacement. This article presents these findings in a thorough manner, and in doing so conveys the ability of a HMS to provide realistic examples of thermal behavior, to estimate conditions at locations free of measurement devices, and to suggest areas of concern for future manual inspections. Furthermore, it provides evidence that a HMS is not only helpful for bridge design and management, but also for the development of itself.

Measuring and modelling the thermal performance of the Tamar Suspension Bridge using a wireless sensor network

“…While the use of safety factors is widely accepted as good engineering practice, the lack of detailed knowledge about the thermal behaviour of complex bridge structures can sometimes lead to excessively over-estimated thermal movements. Even worse, despite the use of safety factors, serviceability failures such as locked expansion joints (Cao et al, 2010) or component failure (Hornby, Collins, Hill, & Cooper, 2012) can occur, leading to questions about the extreme ranges and accumulation of displacement.…”

“…However, neither of these studies considered the temperature of other structural members, which were likely to have directly influenced the deck displacement. Cao, Yim, Zhao, and Wang (2010) identified temperature distributions and time lags for various structural members of the Zhanjiang Bay Bridge (cable-stayed, 480 m main span) in China, and how these influenced the displacement of the bridge deck and towers. Since their results were based on four days of data collected during summer, the interesting findings of this study are not necessarily indicative of the general thermal behaviour of the bridge.…”

Thermal Load in Large-Scale Bridges: A State-of-the-Art Review

“…The minimum effective temperature of bridge deck, main cable, and air is almost the same, while the maximum effective temperature of bridge deck is significantly higher. Cao et al [74] studied the monitored temperatures including steel deck, stayed cables, and concrete tower of the Zhanjiang Bay Bridge, located in an inner gulf of South China, and found that the maximum temperature gradient in the steel girder was more than twice the original design value. The concrete temperature lagged significantly behind ambient air by 5-6 hours, and stayed cable temperatures were between those of ambient air and concrete.…”

Real-time quantitative evaluation on the cable damage of cable-stayed bridges using the correlation between girder deflection and temperature

“…The abnormal change of static girder deflection indicates the occurrence of cable damage. 31,32 Hence, it is feasible that cable damage is quantified using the abnormal change of static girder deflection. For example, our previous research revealed that cable damage resulted in the abnormal change of linear correlation between static girder deflection and uniform temperature, which was used for damage quantification in the Zhijiang Bridge.…”