Structural deformation is an important consideration in the health monitoring of bridges, and its dependence on temperature variations is quite complex. Based on field measurements performed for an operational cable-stayed bridge, the proposed study investigates mechanisms of thermally induced variations in girder length and mid-span deflection through plane geometric and finite element analyses. The objective of this study is to understand the behaviour of such bridges over annual and diurnal cycles. It has been observed that the girder length and mid-span deflection of a cable-stayed bridge exhibit different modes of the temperature–response correlation. Thermally induced changes in girder length are solely governed by the average girder temperature, and its annual variation in amplitude is significantly larger compared to the diurnal variation. However, thermally induced mid-span deflections are simultaneously influenced by the cable temperature and average girder temperature, and these do not vary monotonously with temperature, thereby resulting in nearly equal variation amplitudes over both annual and diurnal cycles. Temperature-induced deformations of a cable-stayed bridge could well be approximated through multiple linear superposition of thermal-expansion effects of individual components. Besides thermal-expansion coefficients of structural materials, the temperature dependency of mid-span deflection of a symmetrical twin-tower cable-stayed bridge is closely related to the ratio of tower height above the deck to central span of the girder as well as span ratio of the side span to central span. The proposed simplified formulae to estimate the sensitivities of temperature effects could be readily extended to other cable-stayed bridges with different geometric arrangements, thereby providing valuable insights into thermally induced deformation of such bridges.

This work provides a comprehensive review of previous studies concerning the static thermal behaviors of various types of bridges, including beam bridges, arch bridges, cable-stayed, and suspension bridges. Given that thermal behaviors are closely associated with the temperature distribution of bridges, the basis of the heat transfer analysis is briefly introduced first. The studies of the temperature distribution and the temperature actions of each type of bridge are then reviewed from the perspective of theoretical analysis, numerical simulation, experimental tests, and field monitoring. Finally, some existing problems are discussed, and future research topics are recommended.

This study proposes analytical formulas of the temperature-induced displacements that can be applied to general suspension bridges with any number of spans. The analytical formulas take account of the tower lateral stiffness and the elastic deformation of cables caused by the tension changes, which have not been studied in previous studies. The derived formulas are validated by the field monitoring data of the four-span Maanshan Yangtze River Bridge. A succinct unified one-dimensional formula is further derived for practical use. This study enables engineers to better understand the behaviour of suspension bridges and to predict the thermal deformation in a simple, generalized way.

Six years of wind data are used to investigate the statistical characteristics of general and strong winds acting on the Donghai Bridge, a sea-crossing bridge in China. The general wind at the bridge site shows a relatively stable annual repeatability, and the discrepancies are found between the measured wind field parameters and those suggested by the design code. For strong winds, both the 10-min mean wind speed and the turbulent variance greatly exceed those of general winds, while the turbulence intensity, integral length scale, and gust factor do not exhibit any noticeable quantitative trends. The measured wind spectra of both general and strong winds show a shift toward the high-frequency range compared with Simiu’s spectrum (along-wind direction). The wind measurements at the bridge site are easily interfered with the bridge structure itself, resulting in a greater turbulence along the bridge axis and a higher turbulent kinetic energy in the high-frequency range, which needs to be considered in designing structural health monitoring systems in the future. This study provides field evidence for the wind-resistant design and evaluation of long-span sea-crossing bridges.