A compact and simpler formulation of the component method for steel connections L.M. Gil-Martín, E. Hern  andez-Montes * Department of Structural Mechanics, University of Granada (UGR), Campus Universitario de Fuentenueva s/n, 18072, Granada, Spain article info Article history: Received 1 September 2019 Received in revised form 17 September 2019 Accepted 23 September 2019 Keywords: Semi-rigid connections Component method Column web panel zone Yield rotation abstract A simpler and a more general formulation of the component method (CM) proposed by the European Standard of Steel Structures is presented in this work. There are two main differences from the meth- odology proposed in Eurocode 3-Part 1e8: first) the moment-rotation curve is obtained from the moment and axial equilibrium equations using only the translational stiffness (springs) of the compo- nents (i.e. avoiding the concept of rotational stiffness), and two) the shear response of the column panel zone is distributed over the joint and located at the level where other components exist, instead of concentrating it at the level of the compression zone, as Eurocode 3-Part 8 does. By using basic kinematic conditions and solving a simple system of equations, all the information regarding the behavior of the joint is obtained. Two examples are presented. © 2019 Elsevier Ltd. All rights reserved. 1. Introduction The component method (CM) allows the flexibility of the joint on the performance of the structure to be introduced. Eurocode 3, Part 1e8 (EC3:1-8) [1] provides a methodology based on the CM, that allows the characterization of the joint in terms of strength and stiffness. In the CM, each focus of deformation of the joint is modeled by a spring (component) whose behavior can be elastic- plastic (which is approximated by a bilinear curve [2]) or rigid- plastic [3] (see Fig. 1). All the components involved in a joint are assembled into a mechanical model. The application of the CM requires the previous characterization of each component of the joint; that is, their force-deformation relationship and the way they are assembled [4]. The characterization of each component is ob- tained either from experiments or from numerical or analytical models. This paper adopts the values of both stiffness and design resistance given by EC3:1-8 [1] for each component. The main advantage of the CM is its versatility [5], and it has been implemented in Eurocode 3 [1] and Eurocode 4 [6]. The procedure included in EC3:1-8 [1] is applicable to 2D joints (welded and bolted end plates and bolted flange cleats) subjected to in-plane bending under monotonic loading conditions [7]. The components involved in these types of joints have been widely studied [8e11] although recent pieces of research have further characterized some components under different conditions [7 , 10e15]. The CM in EC3:1-8 [1] has been formulated as a bending problem with axial force in the connected member not exceeding 5% of the axial capacity of the cross-section of the beam. This is a traditional “modus operandi” in structural engineering, where a division between bending with and without axial force is usually done. The origin of this distinction is not completely clear and recent research on reinforced concrete members has proved that it is unnecessary [16]. Taking the effect of an axial load into account, the CM has been extended to joints loaded in combined bending and axial force in the case of welded beam-to-column steel joints [17] and semi-rigid end-plate joints [18]. In this paper, a simpler and a more general formulation of the CM is presented. In this approach the deformation refers to the section located at the outer part of the flange of the column in contact with the beam. It is assumed that this section remains plane. The components included in EC3:1-8 [1] are considered but the stiffness of the joint is defined as a function of the stiffness of extensional springs, instead of defining an initial rotational stiff- ness, as EC3:1-8 [1] does. The main differences from the traditional CM are: i) The axial force equilibrium equation is also included, together with the moment equilibrium equation, ii) spring forces can be working either in the elastic or in the plastic range, iii) the component corresponding to the column web in shear is extended over the height of the joint (instead of concentrating it at the level of the compressed flange of the beam as has usually been done [1e4, 15]). * Corresponding author. E-mail addresses: mlgil@ugr.es (L.M. Gil-Martín), emontes@ugr.es (E. Hern andez-Montes). Contents lists available at ScienceDirect Journal of Constructional Steel Research journal homepage: www.elsevier.com/locate/ijcard https://doi.org/10.1016/j.jcsr.2019.105782 0143-974X/© 2019 Elsevier Ltd. All rights reserved. Journal of Constructional Steel Research 164 (2020) 105782