Issue 50

C. C. Silva et alii, Frattura ed Integrità Strutturale, 50 (2019) 264-275; DOI: 10.3221/IGF-ESIS.50.22 264 Focused on Structural Integrity and Safety: Experimental and Numerical Perspectives Web rotational stiffness of continuous steel-concrete composite castellated beams Carla Cristiane Silva, Rodrigo Barreto Caldas, Ricardo Hallal Fakury, Hermes Carvalho, João Victor Fragoso Dias Department of Structural Engineering, Federal University of Minas Gerais, Av. Pres. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brazil carlacristianesilva@hotmail.com A BSTRACT . Continuous composite beams can present a global instability known as lateral distortional buckling (LDB). The design code EN 1994-1-1:2004 provides a procedure for the verification of this ultimate limit state, in which the resistant bending moment is calculated considering the behavior of the inverted “U-frame” mechanism. An essential parameter for the determination of this moment is the rotational stiffness of the composite beam, which depends on the web stiffness. The EN 1994-1-1:2004 procedure is restricted to composite beams with solid-web steel sections without openings. This paper presents several numerical analyses of the web rotational stiffness of castellated sections such as Anglo- saxon, Litzka and Peiner typologies . Finally, based on numerical results obtained, three different adjustment coefficients were proposed for the Anglo-Saxon, Litzka and Peiner typologies for the calculation of the web rotational stiffness of the castellated profile. The proposed coefficients provided an excellent adjustment between the results obtained numerically and those obtained from the classical formulation of the plate theory, with an average deviation of 2%, indicating low dispersion and homogeneous results. K EYWORDS . Rotational stiffness; Castellated composite beam; Lateral distortional buckling; Elastic critical moment. Citation: Silva, C. C., Caldas, R. B., Fakury, R. H., Carvalho, H., Dias, J., V., F., Web rotational stiffness of continuous steel- concrete composite castellated beams, Frattura ed Integrità Strutturale, 50 (2019) 264-275. Received: 16.06.2019 Accepted: 16.08.2019 Published: 01.10.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION n continuous and semi-continuous composite beams, in the regions of hogging moment, the bottom flange is compressed, which makes it susceptible to buckling in relation to its major axis of inertia (axis located in the plane of flexion), since the buckling in relation to the its minor axis of inertia is restrained by the web. If the web has insufficient stiffness to prevent lateral flexion, the compressed flange shows a lateral displacement, δ, accompanied by a twist, θ, (Fig. 1), characterizing an ultimate limit state called lateral distortional buckling (LDB). I