Evaluation of Reinforced Steel Moment Connections

9416287 Engelhardt 1994年1月北岭地震造成了前所未有的破坏梁柱连接在钢抗弯框架。 破坏主要发生在标准的焊接法兰-螺栓腹板型钢节点上. 这些故障反映了非延性行为，并提出了严重的问题，目前的方法和标准的设计。 本项目中进行的研究将通过实验评估加固弯矩连接的性能。 将研究两种加固方案。 两者都涉及在连接处添加加强板。 加强板大大增加了连接的抗弯承载力，同时降低了梁翼缘焊缝上的应力水平。 较低的焊接应力将显著降低连接对焊接质量的敏感性。 这种加强连接细节在有限的过去测试中显示出有希望的性能。 然而，需要对这些细节进行额外的大规模验证，并将由本研究项目提供。 大多数试验将使用具有高屈服强度和高屈服抗拉强度比的梁钢进行，以便对钢筋连接进行严格的试验。 然而，也将使用屈服和屈服抗拉强度受控低值的梁钢进行一些试验。 这些试验将证明钢的强度特性在所观察到的连接失效中的作用，并研究通过控制钢材料性能来改善连接性能的可能性。 该测试项目的结果将为结构工程师和建筑规范官员提供急需的数据，这些数据涉及新钢框架的设计以及现有钢框架的维修或改造。 这是一个北岭地震项目。 ***

9416287 Engelhardt The January 1994 Northridge Earthquake caused unprecedented damage at beam-to-column connections in steel moment resisting frames. The failures occurred largely at the standard welded flange - bolted web type of steel moment connection. These failures reflected nonductile behavior, and has raised serious questions on current methods and standards of design. The research undertaken in this project will experimentally evaluate the performance of reinforced moment connections. Two reinforcing schemes will be investigated. Both involve the addition of reinforcing plates at the connection. The reinforcing plates substantially increase the flexural capacity of the connection, and at the same time, reduce stress levels on the beam flange welds. The lower weld stresses will significantly reduce the sensitivity of the connection to welding quality. Such reinforced connection details have shown promising performance in limited past tests. However additional large scale verification of these details is needed, and will be provided by this research project. Most tests will be conducted using beam steels with high yield strength and high yield to tensile strength ratio, in order to provide a severe test of the reinforced connections. However, some tests will also be conducted using beam steels with a controlled low value of yield and yield to tensile strengths. These tests will demonstrate the role of steel strength characteristics in the observed connection failures, and investigate the possibility of improved connection performance through control of steel material properties. The results of this testing program will provide urgently needed data for structural engineers and building code officials involved with design of new steel moment frames, as well as the repair or retrofit of existing steel moment frames. This is a Northridge Earthquake project. ***