Monitoring and Evaluating the Damage to Shear Connectors in Steel–Concrete Composite Beams by Curvature-Based Indicators Through Vibration Tests

In order to assess the workability of shearing connectors of steel–concrete composite beams (SCCBs), this manuscript proposed a novel solid-slipping nonlinear finite element (FE) model, which is independent of stiffness-slip function for simply supported SCCBs. The modal curvature difference and the modal flexibility difference curvature were prompted, which are able to evaluate both sole-damage and multi-damage. It was concluded that the proposed indicators can locate the damaged shear studs and quantify the damage degree correctly, having a maximum error of less than 1%. Robust analysis proved that the proposed indicators are still highly precise when the noise level is up to 8%, which is highly significant for further practical application.