Bridge distributed stiffness identification of continuous beam bridge based on microwave interferometric radar technology and rotation influence line

• Published in: Measurement : journal of the International Measurement Confederation 2023-10, Vol.220, p.113353, Article 113353
• Main Authors: Zhang, Guangwei, Zhao, Wenju, Zhang, Jian
• Format: Article
• Language: English
• Subjects: Bridge distributed stiffness; Continuous beam bridge; Displacement influence line; Microwave interference radar; Rotation influence line
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2023.113353

•Develop a lightweight radar device and enable simultaneous monitoring of multi-point rotation influence lines.•Continuous beam decoupled into simply supported beams by using rotation and MEA is obtained quickly by superposition method.•Realizing the stiffness identification of continuous beam bridge and validating the proposed method through a laboratory experiment. Continuous beam bridges are a widely used and prevalent type of bridge. As material properties degrade over time, the bridge stiffness decreases, leading to a reduction in bearing capacity. Accurate identification of bridge stiffness is crucial for safe operation, but there are few studies on identifying the stiffness of continuous beam bridges. This paper proposes a novel method to identify regional stiffness distribution using microwave interference radar technology and rotation influence lines. Firstly, the regionally distributed multi-point displacement influence lines (DILs) are procured via an innovatively designed lightweight radar device and the multi-point rotation influence lines (RILs) can be subsequently derived through a difference method. Utilizing the derived multi-point RILs, the continuous beam is decoupled into multiple-span simple beams featuring additional moment couples. Then the moment envelope area (MEA) can be computed by integrating the superposition principle and the curvature envelope area (CEA) can be determined using multi-point DILs. Finally, the bridge distributed stiffness can be obtained by combining the MEA and CEA of the monitored area. To verify the validity of the proposed method, a laboratory experiment involving a continuous beam is conducted to identify its’ bridge distributed stiffness (BDS).