Detecting Hinge Joint Damage in Hollow Slab Bridges Using Mode Shapes Extracted from Vehicle Response

Abstract

Hinge joint damage is the main defect affecting the safety of assembled hollow slab bridges. The timely discovery of hinge joint damage is significant for guaranteeing the structural safety of assembled hollow slab bridges. This paper presents a damage detection approach for hinge joints of hollow slab bridges using mode shapes extracted from moving vehicle responses. A stationary excitation vehicle equipped with a shaker excites a bridge, another vehicle moves along the driving path, and its acceleration is collected to extract the mode shape, which is called the stationary excitation extraction mode (SEEM) method. First, the theoretical analysis model of the proposed method is established to analyze the response of the vehicle–bridge system, and the mode shape is extracted from vehicle acceleration by the Hilbert transform. An algorithm that requires no baseline is adopted to detect damage from the extracted mode shape. Then a procedure for damage detection in field testing is proposed in which the determination of important parameters is explained, including excitation frequency, moving vehicle departure time, and narrowband filtering. Finally, factors that affect the accuracy of the approach are studied by numerical analysis, including road roughness, vehicle speed, damage degree, and damage location. The results demonstrate that the damage detection approach for hinge joints is feasible at low vehicle speeds.