Re-evaluation of Conventional Seismic Beam-to-Column Flange Steel Connection

本项目对钢梁柱节点进行了协调研究。研究将集中在焊接和连接的基本问题上。一些子组合将被测试来研究：背杆的作用。通过对背衬条进行实验，并将这些背衬条移走，对焊缝根部进行清理和重新焊接，将记录性能改善的程度。2. 全熔透坡口焊缝端部的焊坝和漏缝的影响。如果能做一些实验来说明这种水坝与径流水闸的影响，那将是很有价值的。3. 一般采用FCAW高沉积电极。虽然FCAW高沉积电极几乎被普遍使用，但使用GMAW（棒）的实验室经验往往显示出更好的效果。4. 预热和控制冷却对接头完整性的贡献。超出或违反AWS指南的情况将表明对该参数的敏感性。5. 尺寸对接头完整性的影响。在北岭地震中许多失效的节点中，由于对长跨度的要求，钢构件尺寸非常大。6. 改进了大尺寸连接的细节。将研究一些可能的细节，以通过迫使关键的塑性铰链远离柱的表面来增强这种连接。考虑对几个不同尺寸的样品进行测试。这可能包括带有混凝土板的试件。能力分析将用于确定构件尺寸，以及制定设计要求。7. 残余应力分布。残余应力加上死活（地震）荷载所施加的应力，可能导致破坏类型，在受损区域的钢建筑接缝中反复观察到。8. 悬臂梁-柱组件。计划制造和测试两个传统的梁柱组件。9. 立柱两侧的悬臂。由于资金的限制，只考虑了一个标本。该试验的主要目的是研究面板区域以及梁的连接。该项目与加州大学圣地亚哥分校和德克萨斯大学奥斯汀分校的伙伴项目协调。这是北岭地震项目。＊＊＊

9416457 Popov A coordinated research effort on steel beam-to-column joints is conducted in this project. The study will concentrate on the fundamental problems of welding and connections. Some subassemblages will be tested to study: 1. The effect of backing bars. By experiments with backing bars and with such bars removed and weld roots cleaned and rewelded, the extent of improvement in behavior would be documented. 2. The effect of dams and run-off tabs at the ends of full- penetration groove welds. A few experiments illustrating the influence of such dams versus run-off tabs would be valuable. 3. The general use of FCAW high deposition electrodes. Although the FCAW high deposition electrodes are almost universally used, laboratory experience using GMAW (stick) often shows better results. 4. The contribution of preheat and controlled cooling to the integrity of joints. Cases where AWS guidelines are exceeded or violated would indicate sensitivity to this parameter. 5. The effect of size on joint integrity. In many of the failed joints during the Northridge Earthquake, steel member sizes, driven by desire for long clear spans, were very large. 6. Improved details for large-size connections. Some possible details will be studied for enhancing such joints by forcing the critical plastic hinge away from the face of the column. Testing of several specimens of different size is contemplated. This may include specimens with concrete slabs. Capacity analyses will be used in establishing member sizes, as well as in developing design requirements. 7. Residual Stress Distribution. The residual stresses together with those imposed by dead and live (earthquake) loads that can cause failures of the type repeatedly observed in steel building joints in the damaged area. 8. Cantilever Beam-Column Subassemblages. It is planned to fabricate and test two conventional beam-column subassemblages. 9. Cantilevers on Both Sides of Col umn. Due to limitation of the funds, only a single specimen is contemplated. The main purpose of this test is to study the panel zone, as well as beam connections. This project is coordinated with companion projects at the University of California at San Diego and at the University of Texas at Austin. This is a Northridge Earthquake project. ***