Experimental study on the failure process of large shear key joints based on NDT methods

Dry joints with keys are often used in precast concrete segmental bridges (PCSBs) to transfer shear stresses. Large dry joints with keys can often provide greater shear bearing capacity, which can meet the needs of rapid construction and simple assembly. This study focuses on the shear response of super‐sized dry joints with keys under direct shear. Various monitoring methods, including digital image correlation (DIC) and distributed optical fiber sensing (DFOS), were used to systematically study the stress process of large concrete keys. The results show that as the size of the key teeth increases, the shear bearing capacity and ultimate vertical displacement of the specimens also increase. DIC and DFOS techniques provide detailed information on key tooth failure, which is beneficial for subsequent stress analysis of shear keys.