Design and Analysis of Moment Connections Using Truss Analogy

本计画的目标是建立钢梁柱连接分析的桁架类比法，并发展钢抗弯框架焊接连接的新设计程序与细部作法。 现代钢结构建筑遵循经典的伯努利假设。 梁的弯矩通过翼缘焊缝传递给柱，而剪力由剪力翼片承受，这隐含地假定梁与柱连接处的梁承载力与梁跨中的梁承载力相同。 然而，详细的模型分析表明，剪切翼片附近的连接区域几乎没有应力，而高应力集中发生在凸缘和凸缘焊缝处。 本文采用桁架比拟法建立了梁柱连接的合理传力模型。 该模型假定连接弯矩通过水平弦杆力传递，而连接剪力由斜撑承担。 在弯曲状态下，法兰焊缝将承受复杂的应力状态和过载。 桁架比拟法表明，连接处的梁必然比跨中的梁弱。 新的设计方案？ 基于合理的桁架传力模型。 新的设计策略是通过增加弯曲和剪切加强元件来增加连接附近的梁的能力。 为实现研究目标所需的分析工作已经开展。 本项目的重点是验证桁架模拟方法和完善建议的梁柱连接设计程序所需的实验研究。 总之，结果将形成一个新的连接设计程序和详细的实践全面验证测试的基础。

The objectives of this project are to establish the truss analogy approach for analysis of steel beam-to-column connection and to develop a new design procedure and detailing practice for welded connections in steel moment-resisting frames. Modern steel buildings in the wake of the classical Bernoulli hypothesis. The beam bending moment is transferred to the column through the flange welds, while the shear force is taken by the shear tab, which implicitly assumes the capacity of the beam at the beam-to-column connection is the same as the capacity of the beam in the span. However, detailed model analysis showed that the area of the connection near the shear tab is virtually devoid of stresses, while high stress concentrations occurring the flanges and the flange welds. The truss analogy approach is used herein to develop a rational model of force transfer in the beam-to-column connection. The model postulates that the connection bending moment is transferred through the horizontal chord forces, while the connection shear is taken by a diagonal strut. Under bending, the flange welds will be subjected to a complex state of stress and overloaded. The truss analogy approach shows that the beam in the connection is necessarily weaker than in the span. The new design procedure ? is based the rational truss force transfer model. The new design strategy is to increase the capacity of the beam near the connection by adding a flexural and a shear strengthening element. Analytical work needed to achieve the research objectives has been carried out. This project focuses on the experimental research needed to verify the truss analogy approach and refine the proposed beam-to-column connection design procedure. Together, the results will form a base for full-scale proof-testing of the new connection design procedure and detailing practice.