Cyclic Rotation Capacity of Beam-To-Column Connections Using the Various Steel Grade

Abstract eng:
In the 1995 Kobe earthquake, many steel structures suffered damage at beam-to-column connections. And in those damaged buildings, fractures of a beam flange at the beam-to-column connections were observed. After that, a remarkable number of studies have been conducted to prevent early fracture at beam-to-column connections and enhance the plastic deformation capacity of steel beams. In these researches, it was pointed out that the small joint efficiency of the beam web, which is caused by the out-of-plane deformation of the skin plate of RHS column used for moment resisting frames in Japan, decreases plastic rotation capacity of the beam limited by the fracture of the beam flange. In the high-rise buildings of Japan, the on-site full penetration welding to beam flanges has to be achieved with the bolted beam-web joint (WBFW type connection). However, the bolted beam-web joint has problem of the poor joint efficiency. Recently, the plastic deformation capacity of the WBFW connections subjected to a long-duration earthquake of ground motion with many cycle of small amplitude of deformation has become a very important issue for structural engineers in Japan. The plastic deformation capacity of the WBFW type connections is evaluated by low cycle fatigue characteristics plotted with fracture life as the vertical axis and ductility factor as the horizontal axis. However, it is difficult to evaluate several test results with various test conditions such as steel grade and beam span. In this paper, cyclic loading tests focusing on suggesting an appropriate evaluation method of plastic deformation capacity of WBFW type connections were carried out. Three types of specimen were tested. Each group of specimens has similar joint efficiency and connection details. The 400MPa conventional strength steel was used for the first group of specimen, and the 490MPa conventional strength steel and the 590MPa high strength steel was used for the second and third ones, respectively. The test results can be summarized as follows:(1) the beam-to-column connection made of the 590MPa high strength steel fractured in 14 cycles of constant rotation angle loading of the 1.5θ p , although that of the 400MPa conventional strength steel showed sufficient plastic deformation capacity; (2) the plastic deformation capacity of the 590MPa high strength steel is almost the same as that of the others in evaluation of low cycle fatigue characteristics based on the maximum rotation angle; (3) finally, it was very effective to evaluate several test results with various test condition such as steel grade and beam span.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket