A delaying and neutralizing procedure of bending brittle fracture of glulam beam with inserted steel plates

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 15560392
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Civil engineering materials/Construction/Construction management
• Research Institution: Akita University
• Principal Investigator: USUKI Seizo Akitauniversity, Faculty of Engineering & Resource Science, Professor, 工学資源学部, 教授 (50006681)
• Co-Investigator(Kenkyū-buntansha): GOTOU Fumihiko Akitauniversity, Faculty of Engineering & Resource Science, Assistant Professor, 工学資源学部, 助手 (10261596) ; SASAKI Takanobu Akita Prefectural University, Institute of Woody Technology, Assistant Professor, 木材高度加工研究所, 講師 (00279514)
• Project Period (FY): 2003 – 2005
• Keywords: material / glulam beam / inserted steel plate / epoxy resin / ultimate load / yield point / non-linear / 降伏点

Research Abstract

The glulam beams having a cross section of 120mm × 60mm and a span of 216cm (the span by beam height equals 18) are arranged and the steel plates having a section of 40mm × 9mm are inserted to upper slits of beams and are glued with epoxy resin. On the other hand, one steel plate having the same section as upper steel plate is inserted and glued to lower slits of beams (Type-A), two steel plates having a section of 40mm × 4.5mm are inserted and glued to those (Type-B) and finally, three steel plates having a section of 40mm × 3mm are inserted and glued to those (Type-C). As a results, three types of glulam beams having different inserted steel plate layout in tension sides of beams are provided and tested under consentrated load at mid span.
Then, these have same bending rigidity, as they have same cross sectional area of steel plates in tension sides of beams. The average ultimate load of three Type-A beams is 25.9kN, that of Type-B is 27.1kN and that of Type-C is 30.7kN, respectively. The different of these ultimate loads are depending to yield points of steel plates. This is no doubt, as the load-srain curves of Type-A, B, C reveal non-linearity at different loading points of the curves. The ductile capacity is also follow the order of Type-C, Type-B and Type-A.
As a conclusion, if the glulam beams have same bending rigidity, the type having multiple inserted steel plates in tension side are superior in engineering ability.