偏心支撑框架空间子结构混合试验边界条件模拟方法

Boundary condition simulation in spatial substructure hybrid tests for eccentrically braced frames

数值子结构的建模精度和子结构的边界条件模拟是子结构混合试验中的两个关键问题。为进一步研究这种新型结构试验方法对于空间框架结构的适用性,基于高强钢组合Y形偏心支撑框架模型展开研究。首先建立了一套由OpenSees,OpenFresco试验平台以及MTS加载系统组成的混合试验系统。然后分别针对2层、3层和4层3跨高强钢组合Y形偏心支撑框架,取底层带有偏心支撑的框架部分作为试验子结构,其余部分作为数值子结构在OpenSees中进行模拟。在混合试验之前,利用已有单榀试件拟静力试验结果对数值子结构的建模方法进行了数值模拟验证。最后选取El Centro波作为原始输入地震波,针对试验子结构的平动模拟和竖向荷载作用进行了一系列空间子结构混合试验。结果表明:通过数值模拟验证拟静力试验结果的方式,可以为混合试验中数值子结构的建模提供参考依据;采用双作动器水平加载来实现试验子结构的平动,可以有效考虑数值子结构对试验子结构的边界约束;竖向荷载的考虑,可以更真实的模拟试验子结构的重力二阶效应。

The modeling accuracy of numerical substructure and boundary condition simulation of substructure are two key problems in substructure hybrid tests.Here,the applicability of this new structural test method to spatial frame structures was further studied based on the high-strength steel Y-eccentrically braced frame(Y-HSS-EBF)model.Firstly,a hybrid test system composed of the software OpenSees,OpenFresco test platform and MTS loading system was established.Then,for 2-story,3-story and 4-story 3-span Y-HSS-EBFs,respectively,frame parts with eccentrically braced bottom story were taken as test substructures,and rest parts as numerical substructures were simulated in OpenSees.Before hybrid tests,numerical simulation verifications were performed for the modeling method of numerical substructures by using the existing pseudo-static test results of single-span frame specimen.Finally,El Centro wave was selected as the original input seismic wave,and a series of spatial substructure hybrid tests were conducted for translational simulation and vertical load action of test substructures.The results showed that quasi-static test results verified by numerical simulation can provide a reference basis for modeling of numerical substructures in hybrid tests;horizontal loading of double actuators is used to realize translation of test substructures,and effectively consider boundary constraints of numerical substructures on test substructures;considering vertical load can more truly simulate the gravity second-order effect of test substructures.