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Strain Rate Effect on Reinforced Concrete Members under Cyclic and Dynamic Loading

循环和动力荷载作用下钢筋混凝土构件的应变率效应

基本信息

批准号：
14350296
负责人：
OTANI Shunsuke
金额：
$ 4.54万
依托单位：
Chiba University (2003)The University of Tokyo (2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350296/
关键词：
Strain Rate Loading Rate Reinforced Concrete Members Strength Failure Mode Ductility Test Loading History 動的繰り返し鉄筋コンクリート靱性

项目摘要

To simulate accurately the behavior of building structural systems under earthquake loading, the model for the structural members should be accurate enough in particular under dynamic and cyclic loading condition. Hence, one-third scale nine-teen reinforced concrete cantilever beam specimens were tested to failure to compare their behavior under dynamic and quasi-static loading condition. The parameters for the test include loading speed as well as amount of longitudinal reinforcement, shear reinforcement, shear-span to depth ratio, shear stress level, strength of transverse reinforcement and loading history. The list of conclusions are as follow,1.The specimens under dynamic loading showed always larger flexural yielding strength than its pair with same parameter tested under quasi-static loading. It is possible to estimate the strength increase quantitatively with affordable presision, by considering the increase in yield point strength of the longitudinal steel and flexural theory.2.As far as the tests in this research concerns, loading speed has little effect on the ductility capacity in terms of the largest deflection at which significant strength decay initiates after cyclic loading. One of the most influential parameter on the ductility is not loading speed, but loading history, i.e. strength decay was delayed significantly in the specimen tested under one directional cyclic loading history.3.A special technique was invented to measure stress in longitudinal bar after tensile yielding and applied to the tests. The observed tensile stress in longitudinal bar were well estimated by flexural theory before flexural yielding, whereas, larger tensile stress is obtained than the theory for tensile reinforcing bars in hinge zone and larger compressive stress in compressive reinforcing bars which gradually increased due to cyclic loading.

为了准确地模拟建筑结构体系在地震荷载作用下的行为，尤其是在动力和循环荷载作用下，结构构件的模型必须具有足够的精度。因此，三分之一比例的十九个钢筋混凝土悬臂梁试件进行了破坏试验，以比较其在动态和准静态载荷条件下的行为。试验参数包括加载速度、纵筋数量、抗剪钢筋数量、剪跨比、剪应力水平、横筋强度和加载历史。主要结论如下：1.动载下试件的弯曲屈服强度均大于准静态下相同参数的试件。通过考虑纵筋屈服点强度的增加和弯曲理论，可以在可承受的精度下定量估计强度的增加。2.就本研究的试验而言，加载速度对循环加载后强度开始显著衰减的最大挠度的延性能力的影响很小。对延性影响最大的参数之一不是加载速度，而是加载历史，即在单向循环加载历史下，试件的强度衰减明显滞后。3.提出了一种测量纵向钢筋拉伸屈服后应力的特殊方法，并应用于试验。在弯曲屈服之前，纵向钢筋的拉应力可以用弯曲理论进行很好的估计，而在铰区受拉钢筋的拉应力比理论值大，受压钢筋的压应力也比理论值大，且随着循环荷载的作用，压应力逐渐增大。