地震模拟振动台试验模型相似设计中的材料弹性模量取值问题研究

Evaluation method for material elastic modulus in the similitude design of structural shaking table test

为了提高结构地震模拟振动台试验的精度,采用常用模型材料的力学性能试验与规范计算理论分析相结合的方式,对混凝土结构、砌体结构及钢结构地震模拟振动台试验模型相似关系设计中的材料弹性模量取值方法进行了系统研究,推荐了混凝土结构、砌体结构及钢结构地震模拟相似关系设计中材料弹性模量的合理取值方法。试验与分析结果表明:模型材料弹性模量的试验值与原型材料弹性模量的规范值可能会存在较大差异,造成模型相似关系中的模型与原型弹性模量比过小,使振动台试验结果失真。因此,当混凝土结构振动台试验模型采用微粒混凝土或砂浆材料浇筑时,模型材料与原型混凝土材料的弹性模型应统一采用规范提供的拟合公式根据材料立方体抗压强度计算得到;当砌体结构振动台试验模型采用小型混凝土砌块制作时,模型材料弹性模量应采用规范拟合公式由材料试验确定的砌体抗压强度设计值计算得到;钢结构地震模拟相似关系中的弹性模量比可采用1.0。以上结论可为不同结构地震模拟振动台试验的模型相似关系设计提供理论依据。

In order to improve the accuracy of shaking table test, the calculation methods for model material elastic modulus in the similitude design of concrete structure, masonry structure and steel structure were studied based on the mechanical testing of model materials commonly used in laboratory and the analysis of calculation method provided by specifications. Then reasonable evaluation methods for elastic modulus of model materials were proposed for the similitude design of shaking table tests： The material test results and the analysis results show that the test value of model material elastic modulus may have great difference from that of prototype materials. As a result, the elastic modulus ratio in the similitude will be too small, which will make the shaking table test results distorted. Therefore, when the shaking table test model of concrete structure is made of microconcrete or mortar, the material elastic modulus of model and prototype should be obtained by using the uniform formula provided by the concrete structure specification according to the cubie compressive strength of materials. When the shaking table test model of masonry structure is made by small concrele hollow block, the elastic modulus of model materials should be calculated with the method provided by masonry structure specification based on the compressive strength obtained by the material test. The elastic modulus ratio in the similitode design of steel structure shaking table test can be set to 1. 0. The conclusions above can provide a basis for the smilibak designing in shaking table tests of different structures.