Recent developments in bridge weigh in motion (B-WIM)

Abstract

Bridge weigh in motion (B-WIM) uses accurate sensing systems to transform an existing bridge into a mechanism to determine actual traffic loading. This information on traffic loading can enable efficient and economical management of transport networks and is becoming a valuable tool for bridge safety assessment. B-WIM can provide site-specific traffic loading on deteriorating bridges, which can be used to determine if the reduced capacity is still sufficient to allow the structure to remain operational and minimise unnecessary replacement or rehabilitation costs and prevent disruption to traffic. There have been numerous reports on the accuracy classifications of existing B-WIM installations and some common issues have emerged. This paper details some of the recent developments in B-WIM which were aimed at overcoming these issues. A new system has been developed at Queens University Belfast using fibre optic sensors to provide accurate axle detection and improved accuracy overall. The results presented in this paper show that the fibre optic system provided much more accurate results than conventional WIM systems, as the FOS provide clearer signals at high scanning rates which require less filtering and less post-processing. A major disadvantage of existing B-WIM systems is the inability to deal with more than one vehicle on the bridge at the same time; sensor strips have been proposed to overcome this issue. A bridge can be considered safe if the probability that load exceeds resistance is acceptably low, hence B-WIM information from advanced sensors can provide confidence in our ageing structures.

State-of-the-art review on bridge weigh-in-motion technology

“…It can be seen that each FAD sensor picked up five peaks corresponding to the five axles. However, it should be mentioned that clear peaks in the strain signal might not occur if the wheel load is directly applied over the beam (Lydon et al, 2015). In practice, a correlation function is usually used to calculate the vehicle speed.…”

“…In recent years, much effort has been made to continuously improve the accuracy of the existing algorithms and to develop novel algorithms to extend the applicability of BWIM technologies. Lydon et al (2015) provided a general review on the BWIM theory and critical issues emerged during the current practice along with detailed case studies of BWIM applications. The review presented herein will focus more on the technical aspects of the BWIM technology including the fundamental methodologies and the field implementation of BWIM systems.…”

First-passage probability of the deflection of a cable-stayed bridge under long-term site-specific traffic loading

“…25 In practice, WIM systems can be used for a wide range of tasks, such as protection and management of highways and other infrastructure investments. In this study, WIM measurements are used for statistical analysis of the traffic loading.…”

Bridge weigh-in-motion using fibre optic sensors

“…The theoretical response is the product of axle weight and the relevant influence ordinate, summed over all axles on the bridge. In recent years there have been extensive developments in the area of BWIM, as documented in the literature (Lydon et al, 2015;Richardson et al, 2014). In the most sophisticated algorithms, the static equations of Moses (1979) have been replaced by a system of differential equations of motion in an approach known as moving force identification (González et al, 2008;Law and Fang, 2001;Law et al, 1999;OBrien et al, 2009;Rowley et al, 2009).…”