Axial-Load Resistance of a Novel UHPFRC Grouted SHS Tube-Sleeve Connection: Experimental, Numerical, and Theoretical Approaches

Experimental, numerical, and theoretical analyses were conducted of the axial load resistance a novel ultrahigh-performance fiber-reinforced concrete (UHPFRC) grouted square hollow section (SHS) tube sleeve connection. The experimental study tested 10 full-scale specimens with varying shear key spacings, grout thicknesses, lengths, volume proportions steel fiber in UHPFRC. Two types failure modes observed: (1) for connection high strength part, mode was fracture inner tube; (2) lower crushing significant bond-slip between tube. To understand further transfer mechanism connection, an advanced three-dimensional (3D) nonlinear finite-element (FE) model built to simulate load–displacement behavior, state stress strain, crack development grout. Based on test FE results, new derived predict axial-load proposed considers effect shape material parameters, is applicable UHPFRC SHS different corner radii. Validation versus results showed that can provide reasonably effective accurate predictions subjected tension.