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

点击翻译按钮获取中文摘要

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.