Experimental characterization of an orthogonal joint for laminated glass without metal components

A first experimental assessment of a novel, metal-free orthogonal connection system for laminated glass plates, which uses in-situ injected mortar layers and structural silicone, is presented. The system features a horizontal glass element slotted into a vertical pane, with mortar blocks acting as compression wedges while silicone is utilized to resist sliding forces. Through combined push-out and bending tests, we established the joint performance across ultimate limit states, including accidental glass fracture. Key findings are: near-linear moment-rotation until peak load; exceptional rotational capacity, exceeding 10 ° ; high post-peak ductility, with ultimate failure occurring at 3.4 to 4.3 times the peak rotation; controlled stiffness reduction due to sequential mortar cracking, preventing catastrophic failure even under large deformations. We interpret this behaviour using a simple mechanical model that treats the mortar blocks as compression-only springs and employs an overall energy-based criterion for crack propagation. Although primarily designed for glass staircases, where load-bearing parallel stringers rely on these joints for lateral stability, buckling restraint, and handrail load transfer, the system’s strength, ductility, and minimal visual impact make it highly promising for a wider range of transparent architectural applications. • The glass joint integrates a mortar/silicone-secured tread interlocked in a slotted stringer. • In staircases, joints transfer handrail loads and provide lateral stability against stringer buckling. • Tests confirm post-peak rotational ductility ( > 10 ° ) with controlled stiffness degradation. • Sequential mortar cracking avoids catastrophic failure even after accidental glass breakage. • A spring model reproduces post-peak response assessing mortar cracking by energetic criteria.