Experimental study on compression–bending damage of segmental joints based on acoustic emission

Abstract

The damage evolution of segmental joints under compression–bending loads is critical in the structural design and strengthening of segmental structures. In this study, a loading device that can maintain the pure bending state of the joint is designed based on the deficiency of existing test methods in boundary conditions. Failure tests under positive and negative bending are performed to investigate the damage of segmental joints under high axial pressure, and the acoustic emission (AE) devices are adopted to measure the joint damage quantitatively. Based on the test results, the main conclusions are as follows: The damage process of the joint is divided into three stages, and the occurrence of clear peaks in the AE count signifies that the joints reached failure state; The development of joint damage location can be divided into the damage location increasing stage and the damage degree deepening stage; The damage of segmental joints under high axial pressure is mainly distributed around the core-pressure zone of the joint, this area is prone to cracking and crushing, and the joints are weaker under negative bending, and damage is more severe; Joint damage along the direction vertical to the joint surface ranges between ±0.855h (positive bending, where h is the height of joint) and ±0.584h (negative bending), moreover, the damage range along the joint surface is approximately 0.2h–0.7h from the compression zone, furthermore, the damage distribution along the segment width is concentrated at the bolt, and the damage range is approximately 0.4b (where b is the averaged segment width of each bolt).