Influence of roller-bending on RHS steel arches: Experimental and numerical investigation

An experimental and numerical investigation of the roller-bending influence on the in-plane behavior of rectangular-hollow-section steel arches is presented. Twelve circular roller-bent specimens, grouped in two sets of curvatures, were tested under tensile and compressive loading at the crown. Finite element models were developed to simulate in detail the curving procedure as well as the compression and tension tests and implicit static analyses accounting for geometric and material nonlinearities were carried out. Good quantitative and qualitative agreement was achieved between numerical and experimental results, in terms of load-displacement equilibrium paths, strain-gauge measurements and deformed shapes. The arches under compression exhibited a gradually softening response, attributed to the Bauschinger effect. Locked-in stresses and plastic strains demonstrated a non-symmetrical layout in which significant concentrations were located at the edges of the bottom flange; extended plastification was observed due to the induced shear. The influence of roller-bending on the overall structural behavior was assessed through the comparison of identical roller-bent and stress-free numerical models under various load conditions. Residual stresses were found to have a varying effect up to 10% on the overall response of arches, depending on the axial-bending interaction that takes place in each loading case.