Pre-stressed bolted joints are widely used in civil structures and industries. The tightening force of a bolt is crucial to the reliability of the joint connection. Loosening or over-tightening of a bolt may lead to connectors slipping or bolt strength failure, which are both harmful to the main structure. In most practical cases it is extremely difficult, even impossible, to install the bolts to ensure there is a precise tension force during the construction phase. Furthermore, it is inevitable that the bolts will loosen due to long-term usage under high stress. The identification of bolt tension is therefore of great significance for monitoring the health of existing structures. This paper reviews state-of-the-art research on bolt tightening force measurement and loosening detection, including fundamental theories, algorithms, experimental set-ups, and practical applications. In general, methods based on the acoustoelastic principle are capable of calculating the value of bolt axial stress if both the time of incident wave and reflected wave can be clearly recognized. The relevant commercial instrument has been developed and its algorithm will be briefly introduced. Methods based on contact dynamic phenomena such as wave energy attenuation, high-order harmonics, sidebands, and impedance, are able to correlate interface stiffness and the clamping force of bolted joints with respective dynamic indicators. Therefore, they are able to detect or quantify bolt tightness. The related technologies will be reviewed in detail. Potential challenges and research trends will also be discussed.

The paper takes the corrosion fatigue damage of cable or sling in the actual bridge as a starting point. The high-strength steel wire is chosen as the basic component to study the corrosion fatigue failure mode. The service life prediction model is put forward, which provides a basis for future research. In this paper, the S-N curves of the steel wire with the different corrosion degrees are given through fatigue tests of six groups of steel wire under different corrosion conditions. The results show that the higher the corrosion degree, the steeper the S-N curve, and the fatigue life considering corrosion are much lower than that without considering corrosion. Finally, a fatigue life prediction model considering the coupling effect of corrosion fatigue is proposed and embedded into Abaqus v6.14 (Dassault, Paris, French). The calculation results show that the fatigue model considering the corrosion can predict the service life to some extent.

The authors wish to make the following corrections to this paper