A dual-sensor AE localization method for damaged steel tendon in prestressed concrete girders using waveguide rods

Abstract

Prestressed steel tendons, as the key load-bearing component of prestressed concrete girders, will inevitably suffer damage, threatening the bridge’s safety and durability. Existing methods of locating damage to prestressed steel tendons necessitate the arrangement of numerous acoustic emission (AE) sensors outside the girder. To reduce the AE monitoring costs of the actual bridge, a dual-sensor AE localization method is proposed to monitor which steel tendon is damaged in a prestressed concrete girder. The key to implementing the proposed method is using a waveguide rod to preconnect the prestressed steel tendons inside the girder. To validate the feasibility of the proposed method, simplified positioning tests were performed on a test platform connected by waveguide rods, which includes connection forms of rebar welding, rebar adhesion, steel plate welding, and steel plate adhesion. Furthermore, the practicality of the proposed method was demonstrated by preinstallation of waveguide rods within a posttensioned prestressed hollow slab. Results indicate the dual-sensor localization method could precisely determine which prestressed steel tendon is suffering damage regardless of ambient AE noise, where AE wave velocity for localization could be selected empirically. The proposed method helps to reduce the cost of AE-based tendon breakage monitoring of bridges.