鉄骨の脆性破断に及ぼす溶接入熱の影響 : 鉄骨破断に関する研究 その2

抄録

Brittle fracture observed in steel buildings during the 1995 Hyogoken-Nanbu Earthquake is attributed to unexpectedly poor behaviors of welded connections. This study deals with welding effects on brittle fracture which was planned in the second series of full-scale fracture test in an extensive research project. Two types of 490MPa-tensile-strength, 40mm- thick steel plates having 150J and 45J in O-℃ Charpy impact energy absorption were tested, and two types of welding, i. e., C0_2 and electroslag weldings which introduce moderate and huge amounts of heat input, respectively, were examined. Major findings are as follows : all specimens failed brittle and there was no chance of ductile rupture during the development of plastic deformation without buckling instability ; welding heat input caused decrease in plastic deformation capacity of steel members prior to brittle fracture ; and a larger heat input escalated the reduction of capacity, however the mother steel having a larger Charpy impact energy provided a higher deformation capacity even after welded.