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Study on Development of Steel-Free Concrete Deck Slabs

无钢混凝土楼承板的开发研究

基本信息

批准号：
11555114
负责人：
KAWAKAMI Makoto
金额：
$ 3.33万
依托单位：
Akita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

(1)First series of loading tests for steel-free slabs were carried out to clarify ultimate strength and deflection. In these tests, the thickness and width of steel plate used to confine the concrete slabs were considered as variable parameter. From these tests results, the increase of confinement ratio has drastically influenced the change of failure mode from bending to shear failure. However higher confinement ratios than 2% have not increased the strength significantly.(2)Effect of the end supports condition and prestressing on the flexural behavior of steel-free slab by undergoing an experimental and theoretical study on a simple supported and fixed slabs in both prestressed and non-prestressed cases were investigated. The results obtained from the second series of tests can be summarized as follows ; 1)End support confinement is efficient in restraining the steel-free slabs before cracking, but it is not reliable after cracking. 2)External prestressing is effective in increasing both cracking and ultimate loads.(3)Third series of load tests are punching tests on six full scale steel-free slabs transversely prestressed with unbonded external bars. The obtained results showed that unbonded prestressing and concrete strength increased the ultimate punching load to some extent but no considerable effect on increasing the cracking load was obtained. Prestressing proved efficiency in controlling cracks development, which means a great improvement on the serviceability of the slab.(4)All results of two years from 1999 to 2001 were summarized and the report was completed.

(1)进行了第一批无钢板加载试验，明确了极限强度和挠度。在这些测试中，用于限制混凝土板的钢板的厚度和宽度被视为可变参数。从这些试验结果来看，限制比的增加极大地影响了破坏模式从弯曲破坏到剪切破坏的转变。然而，高于2%的约束比并没有显着提高强度。(2)通过对预应力和非预应力情况下的简单支撑和固定板进行实验和理论研究，研究了端部支撑条件和预应力对无钢板弯曲行为的影响。第二系列测试的结果可总结如下： 1)端部支撑约束对无钢板开裂前的约束效果较好，但开裂后约束效果不可靠。 2）外部预应力可有效增加开裂和极限荷载。（3）第三系列荷载试验是在六块全尺寸无钢板上进行冲孔试验，用无粘结外部钢筋进行横向预应力。结果表明，无粘结预应力和混凝土强度在一定程度上增加了极限冲切荷载，但对增加开裂荷载没有明显作用。事实证明，预应力在控制裂缝发展方面是有效的，这意味着板的使用性能得到了很大的提高。(4)总结了1999年至2001年两年的所有成果，完成了报告。