There are many steel structures in Iran with semi-rigid saddle connections. It has been observed that, during a strong earthquake, this type of connection can experience a premature fracture, which will endanger the stability of the structure. The present study endeavored to improve the mechanical characteristics including the initial stiffness, yield moment, maximum moment, crack rotation, and load transfer mechanisms of the conventional saddle connections using retrofitting methods. An experimental study was conducted on six full-scale specimens to study the effect of the retrofitting methods on the stiffness, yield moment, and maximum moment of the connection and for the prevention of premature fracture. A numerical study including 88 high-fidelity finite element models was conducted to further evaluate two selected retrofitting methods. Using the generated database, predictive expressions have been proposed for calculating the initial stiffness, yield moment, and crack rotation. The proposed retrofitting methods were shown to improve the mechanical characteristics of conventional saddle connections.

伊朗有许多钢结构采用半刚性鞍座连接。据观察，在强烈地震期间，这种连接可能会过早断裂，这将危及结构的稳定性。本研究致力于使用改造方法改善传统鞍座连接的机械特性，包括初始刚度、屈服力矩、最大力矩、裂纹旋转和载荷传递机制。对六个全尺寸试样进行了实验研究，以研究改造方法对连接的刚度、屈服力矩和最大力矩以及防止过早断裂的影响。进行了包括 88 个高保真有限元模型的数值研究，以进一步评估两种选定的改造方法。使用生成的数据库，已经提出了用于计算初始刚度、屈服力矩和裂纹旋转的预测表达式。所提出的改造方法被证明可以改善传统鞍座连接的机械特性。