Thermal actions have a great influence on the girder deflection variability of long-span cable-stayed bridges. The main objective of this study is to investigate the variability of the bridge girder deflection under thermal actions. A monitoring-based analysis of thermal actions and temperature-induced bridge girder deflection for a combined highway and railway cable-stayed bridge has been carried out; the correlation between the girder deflections at different positions is analyzed; a detailed analysis on the correlation between the structural temperature and the girder deflections has also been performed. Furthermore, the double thresholds with a specific probability for the deflection estimates are proposed. It is revealed that a strong linear relationship exists between the structural temperature and girder deflections. The proposed method can provide good estimates of the bridge girder deflections based on long-term monitoring temperature data.

Ground penetrating radar (GPR) is one of the most recommended tools for routine inspection of tunnel linings. However, the rebars in the reinforced concrete produce a strong shielding effect on the electromagnetic waves, which may hinder the interpretation of GPR data. In this work, we proposed a method to improve the identification of tunnel lining voids by designing a generative adversarial network-based rebar clutter elimination network (RCE-GAN). The designed network has two sets of generators and discriminators, and by introducing the cycle-consistency loss, the network is capable of learning high-level features between unpaired GPR images. In addition, an attention module and a dilation center part were designed in the network to improve the network performance. Validation of the proposed method was conducted on both synthetic and real-world GPR images, collected from the implementation of finite-difference time-domain (FDTD) simulations and a controlled physical model experiment, respectively. The results demonstrate that the proposed method is promising for its lower demand on the training dataset and the improvement in the identification of tunnel lining voids.

Coupled fatigue and corrosion is more detrimental for RC bridge deck slabs than either fatigue or corrosion separately. The main objectives of this study are to obtain a greater understanding of the deterioration mechanisms and failure modes of RC bridge deck slabs subjected to coupled fatigue and corrosion. Analysis of the joint interaction between chloride-induced steel corrosion and fatigue cracking of concrete is presented. Moreover, the effects of fatigue cracking on the chloride diffusion process and the influences of internal forces redistribution caused steel corrosion on the reinforcement-fatigue stress range were studied. On the basis of the coupled fatigue-corrosion damage mechanism, two fracture-failure modes of concrete bridge decks were proposed and the corresponding limit state functions were deduced. Finally, the performance assessment of an illustrative example shows that the coupled fatigue-corrosion effects obviously reduced the fatigue life of RC bridge deck slabs. It was concluded that the effects of coupled fatigue and corrosion should not be neglected in the fatigue safety design of RC bridge decks.