Abstract

The eight bolted stiffened extended endplate (8ES) and bolted flange plate (BFP) moment connection are two common rigid joints that are widely used in special steel moment frames (moment resisting frames with high ductility). In this study, to investigate these connections' behaviour and capacity, first, verification of finite element assumptions was carried out using the Abaqus software. Then, based on the verification models, by changing different parameters, 17 specimens were designed following the AISC Manual using two beams and three columns to determine the maximum capacity values in a column loss scenario. The finite element analysis represents that the 8ES connection's failure begins near the joint area and at the vicinity of the rib stiffener, and the BFP connections provided no warning of failure before brittle fracture of bolts at the large displacement due to catenary action mode. The plastic equivalent strain, Von-Mises stress, and middle column force–displacement curve were discussed. Finally, a formula is presented based on the numerical results to determine the displacement at the maximum capacity of these connections, a formula is presented based on the numerical results using the Least Square Method (LSM). Finally, the modification factors are presented for the theoretical formula to determine these connections' maximum capacity under column removal demands.

摘要

八螺栓加筋延伸端板（8ES）和螺栓法兰盘（BFP）弯矩连接是两种常见的刚性接头，广泛用于特种钢弯矩框架（高延性抗弯框架）。在本研究中，为了研究这些连接的行为和容量，首先，使用 Abaqus 软件对有限元假设进行验证。然后，基于验证模型，通过改变不同的参数，按照 AISC 手册设计了 17 个试件，使用两根梁和三根柱子来确定柱子损失情况下的最大承载力值。有限元分析表明 8ES 连接的失效始于接头区域附近和加强筋附近，由于悬链线作用模式，在大位移处螺栓脆性断裂之前，BFP 连接没有提供失效警告。讨论了塑性等效应变、Von-Mises 应力和中柱力-位移曲线。最后，根据数值结果提出了一个公式，以确定这些连接的最大容量处的位移，并根据最小二乘法（LSM）的数值结果提出了一个公式。最后，给出了理论公式的修正因素，以确定这些连接在柱去除需求下的最大容量。根据数值结果提出了一个公式来确定这些连接的最大容量处的位移，并根据使用最小二乘法 (LSM) 的数值结果提出了一个公式。最后，给出了理论公式的修正因素，以确定这些连接在柱去除需求下的最大容量。根据数值结果提出了一个公式来确定这些连接的最大容量处的位移，并根据使用最小二乘法 (LSM) 的数值结果提出了一个公式。最后，给出了理论公式的修正因素，以确定这些连接在柱去除需求下的最大容量。