Punching shear performance of composite CFST-RC slab systems: Experimental and numerical evaluation

• Experimental assessment of punching shear behavior in RC slabs supported by embedded square CFST columns. • Evaluation of multiple strengthening techniques including steel bolts, welded bars, hybrid systems, and prestressing. • Strengthening methods increased punching capacity up to 5.47 times and energy absorption up to 10.49 times. • Strengthened connections exhibited a clear transition from brittle punching to ductile failure modes. • A validated nonlinear finite element model accurately pr