Structural performance test and FEM analysis of a thermal break system for slabs using H-Shaped steel and UHPC blocks

The connection between the wall and slab is a critical area in traditional structural systems that affects thermal efficiency and presents structural challenges. This study investigates a novel design to mitigate thermal bridging in residential structures by evaluating the structural performance of connections between ultra-high-performance concrete (UHPC) blocks and H-shaped steel elements integrated with existing slab-wall systems. The primary objective is to develop a design procedure for these connections and assess their mechanical behavior under direct shear and bending loads. The experimental program comprised two specimens for each loading scenario, yielding peak load capacities of 204.4 kN in shear and 76.6 kN m in bending. To validate the tests, finite element (FE) analysis was conducted using LS-DYNA to simulate the response of the specimens. The numerical results closely matched the experimental data, confirming the reliability of the developed FE model. Further parametric analysis revealed that the inclusion of UHPC blocks enhanced the load-bearing capacity by approximately 29.7% in shear and 22.8% in bending, highlighting the potential of this detail for performance structural retrofitting.