Abstract In this study, new equations are developed for predicting the initial stiffness and ultimate moment of flush end-plate connections (FECs). FECs exhibit partially restrained behavior, which affects the distribution of forces and the displacement of a steel frame. Thus, the influences of the nonlinearity of connections on second-order moments are incorporated into structural analysis. FECs bolted to column flanges and welded to beams are investigated. The experimental data of FECs are collected, including initial stiffness and ultimate moment. Finite element analyses are used for analyzing the mechanical behavior of FECs and identifying the fracture mechanism of FECs. The finite element model of FECs is developed using ABAQUS software, and it is verified through comparison with the experimental results of previous studies. The mechanical behavior of FECs is investigated. An improved semi-empirical equation for the initial stiffness is suggested, and it provides good accuracy. A new type of fracture mechanism for FECs is suggested. An equation for estimating the ultimate moment is derived from the suggested fracture mechanism, and it shows good agreement with experimental data.

中文翻译：

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用于预测平端板连接的初始刚度和极限力矩的新方程

摘要 在这项研究中，开发了用于预测平端板连接 (FEC) 的初始刚度和极限力矩的新方程。FEC 表现出部分受约束的行为，这会影响力的分布和钢框架的位移。因此，连接的非线性对二阶矩的影响被纳入结构分析。研究了用螺栓固定在柱翼缘上并焊接到梁上的 FEC。收集 FEC 的实验数据，包括初始刚度和极限力矩。有限元分析用于分析 FEC 的力学行为并确定 FEC 的断裂机制。FECs的有限元模型是使用ABAQUS软件开发的，并通过与以往研究的实验结果进行比较来验证。研究了 FEC 的机械行为。提出了初始刚度的改进半经验方程，它提供了良好的精度。提出了一种新型的 FEC 断裂机制。估计极限力矩的方程是从建议的断裂机制推导出来的，它与实验数据显示出良好的一致性。