Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants|
|Research Institution||HIROSHIMA UNIVERSITY|
YONEKURA Asuo HIROSHIMA UNIVERSITY,FACULTY OF ENGINEERING,PROFESSOR, 工学部, 教授 (00034372)
TADROS Maher K. UNIVERSITY OF NEBRASUKA,COLLEGE OF ENGINEERING AND TECHNOLOGY,PROFESSOR, 工学部, 教授
TAZAWA Ei-ichi HIROSHIMA UNIVERSITY, FACULTY OF ENGINEERING,PROPESSOR, 工学部, 教授 (60155067)
周 平 広島大学, 大学院・工学研究科, 日本学術振興会特別研
河合 研至 広島大学, 工学部, 助教授 (90224716)
|Project Period (FY)
1996 – 1997
Completed(Fiscal Year 1997)
|Budget Amount *help
¥9,500,000 (Direct Cost : ¥9,500,000)
Fiscal Year 1997 : ¥4,600,000 (Direct Cost : ¥4,600,000)
Fiscal Year 1996 : ¥4,900,000 (Direct Cost : ¥4,900,000)
|Keywords||ductility / three dimensional confinement / fIexural rigidity / ultimate shear strength / reinforced concrete column / prestressed concrete composite girder / high ductile concrete member / seismic resistant structure / 靱性 / 高靱性コンクリート部材 / 広島大学 / ネブラスカ大学 / ノースリッジ地震 / 阪神・淡路大震災 / 鉄筋コンクリート橋脚 / 炭素繊維|
Generally, ductility of reinforced concrete members is lower steel members because of the brittle characteristics of concrete. Hanshin-Awaji Earthquake and Northridge Earthquake destroyed many infrastructures in an instant. To avoid critical damages of concrete structures, the concrete members with high ductility must be developed.
Nominal tensile strength can be dramatically improve when concrete is triaxially precompressed. To apply triaxial precompression, concrete members must be tie with steel or FRP.Another way is to cast concrete in a steel or FRP pipe, and apply prestress with conventional method. This method create triaxial precompression by which a steel or FRP pipe confines poisson's strain nominal to the prestress.Another method to create triaxially precompressed concrete member is chemical prestressing using expansive concrete in steel or FRP pipes.
The objective of this research is to study mechanical characteristics of the triaxially precompressed members and the applicati
ons, and to develop new type of concrete structures with this concept. The following results were obtained from the research at Hiroshima University in Japan and the University of Nebraska in the US.
1.The ductility of the triaxially precompressed concrete beams subjected to bending moment can reach ten times more than conventionally reinforced or prestressed concrete members.
2.In the study on the mechanical characteristics of triaxially confined concrete, the ultimate load and ductility are improved for the specimens with regular concrete in steel and FRP pipes subjected to axial load, comparing with the conventional reinforced concrete column. And at the same condition, the ultimate load and ductility for an unbond confined concrete column are larger than those for a bond one.
3.The ultimate load and stiffness of confined concrete columns with expansive concrete in steel or FRP pipes subjpcted to axial load are larger than those with regular concrete.
4.The ultimate strength and compressive stiffness of reinforced concrete columns with steel straps are higher than those with deformed round bars in case of the same nominal confining effect. The shear strength of the columns with steel straps subjected to vertical load and cyclic horizontal load is higher than that with deformed round bars.
5.Studies on the applications and feasibility of the new type of structures with triaxially precompressed members to arch structures or composite girders were carried out.
6.Field trip to see Repaired and Retrofitted structures damaged by Hanshin-Awaji Earthquake in Japan and Northridge Earthquake in the US were conducted. Less