## 1 Introduction  
Steel frames have been extensively utilized in structural engineering over recent decades [1, 2, 3, 4], owing to their high load-bearing capacity and ease of assembly. A fundamental element in these systems is the beam-column connection, for which multiple configurations are available [5]. Among them, bolted end-plate connections are particularly well-suited for moment-resisting frames. This type of connection is fabricated by welding a plate to the beam end during shop fabrication, followed by on-site bolting to the adjoining structural member. In addition to their relatively high stiffness, these connections offer enhanced ductility compared to fully welded joints, thereby improving structural safety under seismic loading and reducing the risk of brittle failure [6, 7, 8]. However, the design of steel frames--and especially end-plate connections--can be complex, primarily due to the difficulty in accurately characterizing their semi-rigidstructural response. This behavior is influenced by nonlinear phenomena, including the elasto-plastic properties of steel, large deformation effects, and interactions among individual components [9; 10]. A widely used approach in practice to simplify the design of such complex systems is the equivalent T-stub method, as defined in the Eurocode [11]. Nevertheless, this approach overlooks key nonlinear effects, such as the strain-hardening behavior of steel. To overcome these limitations and achieve higher analytical precision, the finite element method (FEM) offers a robust and versatile alternative. Even before the turn of the millennium, significant attention had been devoted to the numerical modeling of end-plate connections using the FEM, offering detailed insights into their structural behavior. One of the earliest studies was conducted by [PERSON] [12; 13], focusing on four-bolt, unstiffened extended end-plate connections, and included results from a series of experimental investigations. Later, [PERSON] et al. [14] employed FEM to develop a calculation method for predicting the load-bearing capacity and the corresponding moment-rotation relationship. Another notable early application was presented by [PERSON] et al. [15], who investigated the contact interaction between the end-plate and the column flange using FEM. Subsequently, [PERSON] et al. [16] introduced a novel finite element approach, utilizing an elasto-plastic nonconforming 3D solid element with a refined mesh and a relatively simple yet effective contact algorithm. Additionally, [PERSON] and [PERSON] [17] provided a comprehensive overview of FEM-based methodologies for simulating end-plate connections, addressing general modeling challenges. Over the past two decades, the high level of interest in the numerical simulation of end-plate connections has continued. Notably, [PERSON] et al. [18] conducted a detailed investigation into the influence of various parameters on the behavior of pretensioned bolted end-plate connections through both experimental and numerical analyses. Their study demonstrated the potential of finite element modeling and revealed how even relatively minor changes in parameters can significantly affect connection behavior. Furthermore, [PERSON] and [PERSON] [19] examined the impact of initial geometric imperfections, highlighting their considerable influence on the rotational stiffness of the connection. Later, [PERSON] et al. [20] further explored the role of initial geometric imperfections and recommended their consistent inclusion in simulations, as this approach yields the most conservative and safe design outcomes. Additionally, several recent studies have focused on the advanced design of these connections, in which FEM simulations played a key role [7; 21; 22]. A particularly relevant contribution is the work by [PERSON] et al. [23; 24], who conducted both numerical and experimental analyses on web-strip steel plate shear walls with rigid connections.