Monitoring Of Long-span Bridges Research Articles

Effectiveness of GPS technology in monitoring of traffic-induced response of highway steel bridge

Despite some disadvantages, regarding the limited accuracy, the Global Positioning System (GPS) is widely used in monitoring of long-span bridges. This paper is concerned with the analysis of the capabilities and limitations of the use of the GPS technology in monitoring of semi-static and dynamic vertical responses of a highway steel cable-stayed bridge excited by traffic loads. The field test was conducted on the Maxau Rhine Bridge, located over the Rhine River near Karlsruhe, Germany. The so-called baseline method with the Post-Processing mode was applied using two units Leica Viva GS15. The basic characteristics of the GPS background noise before and after filtering were examined in the time and frequency domain. The natural frequencies of the bridge were extracted based on the vertical dynamic displacements recorded in the mid-span of the bridge using GPS and accelerometer. It was shown that the GPS receivers were able to measure only two primary modal frequencies of the bridge. The obtained experimental results proved that the GPS system is an efficient tool in measuring the vertical semi-static displacements of the bridge with satisfactory accuracy. Moreover, GPS is capable of tracking the vertical vibrations of long-period bridges to a few millimeters.

Numerical evaluation of multi-metric data fusion based structural health monitoring of long span bridge structures

This work focuses on structural health monitoring of long span bridges for damage detection. A feature extraction level data fusion based damage isolation strategy is presented using multi-metric sensing. The multi-metric sensing uses two types of sensors, namely strain sensors and accelerometers. The methodology combines the advantages offered by each type of sensors, while at the same time overcomes their limitations. The flexibility index method is applied and the flexibility matrices based on the strain and displacement data are combined after performing co-ordinate transformation. A study has been carried out on a simulated finite element model of the Great Belt East Bridge where realistic damage scenarios like damage in the girder, breaking of hanger cables, pier settlement, and loss of cable pretension were introduced on the structure. The study indicates that multi-metric sensing is indeed necessary as it reduces the possibility of false detections and increases the sensitivity and robustness of the methodology.

Multi-type, multi-sensor placement optimization for structural health monitoring of long span bridges

The paper presents a multi-objective optimization strategy for a multi-type sensor placement for Structural Health Monitoring (SHM) of long span bridges. The problem is formulated for simultaneous placement of strain sensors and accelerometers (heterogeneous network) based on application demands for SHM system. Modal Identification (MI) and Accurate Mode Shape Expansion (AMSE) were chosen as the application demands for SHM. The optimization problem is solved through the use of integer Genetic Algorithm (GA) to maximize a common metric to ensure adequate MI and AMSE. The performance of the joint optimization problem solved by GA is compared with other established methods for homogenous sensor placement. The results indicate that the use of a multi-type sensor system can improve the quality of SHM. It has also been demonstrated that use of GA improves the overall quality of the sensor placement compared to other methods for optimization of sensor placement.

Development and Challenge of Structural Health Monitoring of Long-Span Bridges

This paper reviewed and discussed some key issues of structural health monitoring (SHM) of long-span bridges. Firstly, the current situation of the application of structural health monitoring technique to long-span bridges was summarized in detail. Secondly, starting from the purpose of ensuring the safety of operational bridges, the composition characteristics and functional requirements of structural health monitoring system of long-span bridges were discussed, which include the global design principles of health monitoring system and the design approaches for each subsystem. Finally, some challenges of the technique of SHM were proposed including structural force analysis, the principles of optimized distribution of sensors and the assessment methods of structural damages of bridges etc,.

Application of Global Positioning System Measuring Technology in Safety Monitoring of Long-Span Bridges

With the application of Global Positioning System (GPS) echnology using in the field of modern transport, more and more long-span bridges have set up the GPS system to monitor the real-time deformation in safety monitoring system. Nowadays the highest measuring accuracy of GPS technology achieves millimeter, and the sampling frequency can reach 20Hz. It can solve real-time deformation data and adapt to the complexity and poor working environment. Based on the application of GPS technology using in long-span bridges safety monitoring system, this paper set the Huangpu bridge as the engineering project and demonstrate how to apple the GPS technology in deformation monitoring and security evaluation.

Vibration, control and monitoring of long-span bridges—recent research, developments and practice in Japan

This paper discusses vibration, control and monitoring of long-span bridges, in particular, of cable-supported bridges with emphasis on recent research, developments and practice in Japan. Primary stress is placed on the vibration due to motion-dependent forces such as wind-induced aerodynamic forces and its control. Implementation of passive and active control in the long-span bridges in Japan is described. In the last part of the paper, importance and usefulness of vibration monitoring of long-span bridges is discussed with an actual example.