Experimental study on cyclic behavior of interior demountable beam-to-column composite joints having precast geopolymer concrete slab

Modern construction necessitates eco-friendly structures that minimize carbon dioxide emissions and are designed for easy disassembly, facilitating the reuse of structural components with minimal effort and cost. Facilities employing geopolymer concrete designed for disassembly serve as an exemplary model for such construction. In this research, four full-scale interior demountable steel-concrete composite beam-to-column joints having precast geopolymer concrete slab were conceived, produced, and subjected to cyclic loading tests. A comprehensive examination was conducted on the structural behaviors of interior demountable steel-concrete composite beam-to-column joints, encompassing crack patterns, failure modes, moment-rotation responses, force-displacement curves, strain distributions, shear connector slippage, and energy dissipation. The research examined how the structural behavior of interior demountable composite joints is affected by the diameter of bolted shear connectors and the reinforcement ratio of precast concrete slabs. The results indicated that increased reinforcement in the slab enhances the rotation of the connection, the initial rotational stiffness, the bearing capacity of the joint, and the joint's over-strength. The dissipation of energy is impacted by both the dimensions of the reinforcement in the slab and the diameter of the shear connectors. The joint's stiffness was assessed through an analysis of the bending moment-rotation curve, following the guidelines outlined in Eurocodes 3 and 4. The deformability meets the minimum rotation capacity requirement (0.03 rad) specified by these codes. In summary, bolted shear connectors enable controlled slippage, ensuring a smooth response to applied loads and making this joint well-suited for withstanding cyclic loads, such as those associated with earthquakes. The test results also show that the composite beam to column joints having precast concrete slab and bolted shear connectors can be deconstructed easily at the end of their service life.