PSI - Issue 79

Albena Doicheva et al. / Procedia Structural Integrity 79 (2026) 370–378

371

Keywords: larges deformations; crack on the face of the column; beam-column connection; limite state; shear force; cantilever beam; linearly distributed load; reinforced concrete; asymmetrical cross section

1. Introduction The beam-column connection is a fundamental and still incompletely uncleared element in frame structures. The design and construction of earthquake-resistant beam-column connections is possible with a complete knowledge of the magnitudes of the forces passing in the beam-beam and column-column directions. Hundreds of experimental and analytical studies have been conducted over the past 6 decades. The influence of various variables on the response of frame joints has been investigated. We find such studies in Park and Paulay (1975), Paulay (1989), Javad et al. (2018), Gombosuren and Maki (2020), Hayat et al. (2021), Kim and LaFave (2007), Bonacci and Pantazopoulou, (1993), Alaee and Li (2017), Ramaglia et al. (2022), Doicheva et al. (2023c), Zhuang et al. (2024), Pham et al. (2025), Hu et al. (2025), Ru et al. (2025). The determination of the shear force in Eurocode 8 (2004) becomes capacitive. This is the force that occurs in the longitudinal reinforcing bars of the beam, which pass through the beam-column joint, when the steel yields. We find the same acceptance in Barbagallo et al. (2023). Nowadays, capacitive methods are proposed with additional consideration of the participation of the concrete section and stirrups in the beam-column connection, Shiohara (2001), Pauletta et al. (2015), Fardis (2021), Floridia et al. (2023). In Angiolilli et al. (2023), a 3D model was studied, allowing the material characteristics of the used construction materials to be changed. Control of the shear force under cyclic loading was proposed in Pagnotta et al. (2023). In Wang et al. (2012) proposed a shear strength model for RC beam column joints under seismic loading. In Nicoletti et al. (2023), a method was proposed that allows the determination of the geometric dimensions of the beam-column joint and the number of stirrups. In De Domenico et al. (2023) a machine-learned variable-angle truss model was proposed to predict the shear capacity of reinforced concrete members with transverse reinforcement. These approaches do not answer the question of how large the shear force actually is under specific loads and how it changes when a crack appears and grows between the beam and the column. In this study, expressions will be determined for calculating the forces transmitted from a cantilever beam to the column by the action of a linear distributed load. They will be used to calculate the shear force. The resulting expressions will allow one to track the change in the shear force with a change in the material characteristics and geometry of the beam, Doicheva (2023a), Doicheva (2023b), Doicheva (2024a), Doicheva (2024b), Doicheva (2025a), Doicheva (2025b), Doicheva (2025c), Doicheva (2025d). The results obtained for the magnitude of the shear force will be compared with those given in the literature and the corresponding ones prescribed in Eurocode 8 (2004). 2. Materials Equation (1) illustrates the first quantitative definition of shear force, given by Hanson and Connor (1967).

j C C C V T C C V T T V           S

(1)

Fig. 1. Horizontal joint shear force in the interior RC beam – column connection.