Research on Application of Steel-Concrete Composite Members filled with Rigid Urethane to Structures

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 15560419
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Structural engineering/Earthquake engineering/Maintenance management engineering
• Research Institution: Takamatsu National College of Technology
• Principal Investigator: OTA Teiji Takamatsu National College of Technology, Department of Civil Engineering, Professor, 建設環境工学科, 教授 (20107212)
• Co-Investigator(Kenkyū-buntansha): OKAMURA Miyoshi Yamanashi University, Department of Civil and Environmental Engineering, Assistant, 工学部・土木環境工学科, 助手 (50162889)
• Project Period (FY): 2003 – 2005
• Keywords: Rigid Urethane / Steel-Concrete Composite Bridge / Vibration Test / Damping Ratio

Research Abstract

Steel-concrete composite member, the tension side concrete of which is replaced with light weight urethane, is used efficiently in low height bridges because it helps to reduce bridge weight. However, low height bridges tend to vibrate easily. In the first stage of the research (in 2003), we verified the effect of urethane, performing vibration tests on three steel-concrete composite slab bridges ; two filled with rigid urethane and one filled completely with concrete. The test result showed that rigid urethane increases damping ratio by more than 50 percent.
In the second stage (in 2004-2005), we verified vibration property of steel plates with rigid urethane because we thought that rigid urethane attached to steel plates could reduce noise from the bridge. We performed two kinds of vibration tests (impact loading test and vibration test on a shaking table) on steel plates with various urethane thickness.
Impact loading test : When we dropped a golf ball on a 3mm-thick steel plate with 150mm-thick urethane to check vibration in high-frequency region, damping ratio was approx. 4 times comparing a steel plate without urethane. When we dropped a softball on the above plate to check vibration in low-frequency region, damping ratio was approx. 2 times.
Vibration test on a shaking table : On the other hand, it was confirmed that attaching urethane to steel plates increases the acceleration response of steel plates when vibrating steel plates with rigid urethane on a shaking table.