Acoustic Emission Assessment of Concrete Hinge Joints

Abstract

Concrete hinge joints are present in over 100 bridges in Wales and England, they were introduced into bridge decks as a means of simplifying the design and standardising details on bridges having a range of span and functional requirements. Hinged joints are not easily accessible for inspection or maintenance due to their form and their location over or under live traffic lanes. They are vulnerable to deterioration in the event of bridge deck waterproofing failure, which can cause steel reinforcement bar corrosion. This reinforcement is crucial to the integrity of the joint, and the loss of reinforcement section can induce higher stresses leading to eventual failure by yielding.The aim of these investigations was to determine the effectiveness of the Acoustic Emission (AE) technique in detecting defects in reinforced concrete bridge hinge joints. A laboratory investigation was completed on a 1m length of reinforcement bar. Sensors were attached to the bar during fatigue loading and a fatigue crack monitored. The tests showed that it was possible to locate fatigue cracks within reinforcement bars. A field trial was completed on one hinge joint on the M4 River Usk Crossing. Sensors were attached to the reinforcement steel using wave-guides and onto the concrete face of the joint. Monitoring was undertaken during a one-day period of normal traffic loading and via a series of controlled load tests. Located AE emissions associated with the steel work were low in energy level and activity which suggested that there was no active damage associated with this particular hinge joint, this result was confirmed by X-ray monitoring.

Acoustic emission monitoring of bridges: Review and case studies

“…Since all points lie in the A zone, implying no serious deterioration within monitored zones, the plot aptly portrays the structural health of the new bridge. In-service RC bridges were also assessed by Beck et al [40] and Pullin et al [41], who reported that the reliability of the AE technique of monitoring bridges was in need of an upgrade. Bridge cable monitoring using AE had been set up since the 1970s.…”

Structural health monitoring of a composite bridge using Bragg grating sensors. Part 1: Evaluation of adhesives and protection systems for the optical sensors

“…Health monitoring is also used as a diagnostic tool to detect or infer the presence of defects and to schedule maintenance operations. Assessment of conventional civil structures can be performed by established techniques such as ultrasonic scanning [7], transient pulse and infrared thermography [8][9][10], ground penetrating radar [11] and acoustic emission [12,13]. Although these conventional techniques are adequate and reliable, they are not suitable for real-time and in-situ evaluation of civil structures.…”

Numerical Analysis of Reasonable Hinge Joints Size of Reinforced Concrete Hinged Plates

“…Meanwhile, some experts and engineers had carried out relevant researches at home and abroad. For example, ZHANG Yong-fang had studied the disease and treatment of hinge joints [1]; WANG Tie-cheng had studied the different configurations of hinge joints through experimental [2]; ZHANG Li-fang had comparatively analyzed the difference between bridge transverse connection of transverse steel plates and hinge joints [3]; WEI Hong-tao had studied the influence of concrete crack at slab bottom by depth of hinge joints [4]; Pullin, R. had studied the detection method of fatigue crack in hinge joints [5]. However, all these studies hadn't analyzed the stress state of hinge joints systematically, especially of different internal stress distribution in hinge joints of different construction sizes.…”