RC Wall Plastic Hinge Out-of-Plane Buckling: Analysis Using the Nonlinear Beam-Truss Model

The beam-truss model (BTM), developed for the nonlinear cyclic analysis of reinforced concrete components including softening, is extended to compute the out-of-plane buckling observed in plastic hinges of various slender structural walls. This is achieved by using fiber-section displacement-based elements with PDelta geometric transformation and diagonal truss-elements with Corotational transforma-tion. The BTM is enhanced by considering strain penetration at the base of the walls. This paper discusses the BTM for three test specimens that exhibited out-of-plane buckling and whose response softened as a result of this phenomenon. The test specimens' unsupported height-to wall thickness ratio ranged between 10 and 25. Using the same calibration of the modeling parameters for the development of the three models, the BTM is validated by comparing measured and computed lateral force-displacement responses, out-of-plane displacements, and local strain responses. The BTM accurately computes the force-displacement responses as well as out-of-plane displacements of the test specimens and the buckling behavior. DOI: 10.1061/(ASCE)ST.1943-541X.0002836. (c) 2020 American Society of Civil Engineers.