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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系统在地震荷载下的行为，结构构件的模型应该足够准确，特别是在动态和循环荷载条件下。因此，对三分之一比例的九十钢筋混凝土悬臂梁试件进行了失效测试，以比较它们在动态和准静态加载条件下的行为。试验参数包括加载速度、纵向钢筋数量、抗剪钢筋、剪跨深比、剪应力水平、横向钢筋强度和加载历史。主要结论如下： 1.动态加载下的试件始终表现出比准静态加载下相同参数的试件更大的弯曲屈服强度。通过考虑纵向钢材屈服点强度的增加和弯曲理论，可以以可承受的精度定量估计强度增加。2.就本研究中的试验而言，就循环加载后开始显着强度衰减的最大挠度而言，加载速度对延性能力影响不大。对延性影响最大的参数之一不是加载速度，而是加载历史，即在一个定向循环加载历史下测试的试样中，强度衰减显着延迟。3.发明了一种测量拉伸屈服后纵向钢筋应力的特殊技术，并将其应用于试验。在弯曲屈服之前，通过弯曲理论可以很好地估计纵向钢筋中观察到的拉应力，而在铰接区，获得比受拉钢筋理论更大的拉应力，而受压钢筋则获得更大的压应力，并且由于循环荷载而逐渐增加。