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Development of real-time dynamic substructuring procedures for the seismic testing of steel structures.

机译：开发用于钢结构抗震测试的实时动态子程序。

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摘要

The first specific objective of this PhD project was to develop and validate an RTDS (Real Time Dynamic Substructuring) testing technique that would be suitable for the simulation of the seismic collapse analysis of multi-storey braced steel frames taking into account the possibility of inelastic buckling of the columns. The focus of this first part of the work was on the development of a robust discrete time integration scheme for this particular RTDS application. The second specific objective of this study was to verify if the software OpenSees could model the cyclic inelastic response of steel columns. To better model the behaviour of steel columns, the base code of the OpenSees software was modified to include the effect of residual stress patterns in the nonlinear beam-column elements with fibre sections. Buckling tests on isolated full scale column specimens subjected to cyclic loading were also performed to validate the adequateness of the numerical models, and also to verify if strain rate effects modify the buckling behaviour of columns.;The inclusion of initial stress patterns in nonlinear beam-column elements was achieved by modifying the Steel02 material of OpenSees. Column buckling simulation results were compared to past experimental data. This comparison showed that OpenSees can accurately model the overall buckling behaviour of steel columns under monotonically loaded columns. The effects caused by residual stresses on the buckling responses were found to be of greater importance on the prediction of the first buckling load. The effect of residual stresses becomes less pronounced in the post-buckling range.;Additional column tests were conducted in this project to validate the numerical model for columns subjected to various compression loading conditions. The behaviour of the columns under monotonic and cyclic compression loading was found to be nearly identical. Testing under dynamically applied loading showed that the high strain rates anticipated during seismic events can increase the ultimate strength in the first buckling cycles but are of less important in the post-buckling range. At the end of all buckling tests, the columns still exhibited substantial reserve compression capacity even after having sustained several severe global buckling cycles, local buckles at their mid-height, and very large permanent out-of-plane displacements. This demonstrates the potential for compact sections (Class 1) to accommodate limited yielding excursions and inelastic buckling occurrences during an earthquake without adverse lost in load carrying capacity. Except for strain rate effects, the overall response of the tested columns could be very well predicted using the Steel02 model modified to account for residual stresses. Using the numerical model, it was shown that strain hardening plays a key role in predicting the local stress-strain response in the column plastic hinge. The effects of the strain rate on the steel yield strength should be implemented in the model to better predict the inelastic seismic response and stability of braced frames.;Exploratory nonlinear seismic analyses were performed to investigate the effects of reducing the size of the columns in a two-storey chevron braced steel frames designed according to capacity design principles. The structure examined could withstand a design ground motion without collapse even if column buckling occurred. (Abstract shortened by UMI.);A Rosenbrock-W integration scheme was developed to eventually perform Real Time Dynamic Substructuring (RTDS) experiments involving experimental column buckling. It was shown that the performance, stability and accuracy properties of the scheme can be improved by accounting for the properties of the physical substructure in the Jacobian matrix involved in the integration process. The proposed scheme was proven to be unconditionally stable, second order accurate and yields to explicit displacements and velocities. RTDS experiments on SDOF and MDOF systems in the linear and nonlinear regimes showed that the method can be easily implemented and perform as intended in a testing environment. The tests also provided the opportunity to propose a novel modal decomposition based method to predict the potential adverse effects of experimental errors on the overall response during RTDS tests.
机译：该博士项目的第一个特定目标是开发和验证RTDS（实时动态子结构）测试技术，该技术将适用于考虑非弹性屈曲可能性的多层支撑钢框架地震倒塌分析的模拟。列。该工作的第一部分的重点是针对该特定RTDS应用程序开发鲁棒的离散时间积分方案。这项研究的第二个具体目标是验证OpenSees软件是否可以对钢柱的循环非弹性响应进行建模。为了更好地模拟钢柱的性能，对OpenSees软件的基本代码进行了修改，以包括带有纤维截面的非线性梁柱单元中残余应力模式的影响。还对循环荷载作用下的独立全尺寸柱样本进行了屈曲测试，以验证数值模型的适当性，并验证应变率效应是否会改变柱的屈曲行为。列元素是通过修改OpenSees的Steel02材料实现的。将柱屈曲模拟结果与过去的实验数据进行了比较。该比较表明，OpenSees可以准确地模拟单调加载柱下钢柱的整体屈曲行为。发现残余应力对屈曲响应的影响在预测第一屈曲载荷时更为重要。在屈曲后范围内，残余应力的影响变得不那么明显。在该项目中进行了附加柱测试，以验证承受各种压缩载荷条件的柱的数值模型。发现柱在单调和循环压缩载荷下的行为几乎相同。在动态施加的载荷下进行的测试表明，地震事件期间预期的高应变率可以增加第一个屈曲周期的极限强度，但在后屈曲范围内的重要性较小。在所有屈曲测试结束时，即使经历了几次严峻的整体屈曲循环，在其中间高度处的局部弯曲以及非常大的永久性平面外位移，这些柱子仍显示出相当大的储备压缩能力。这证明了紧凑型截面（1类）在地震过程中能够承受有限的屈服偏移和非弹性屈曲的可能性，而不会对承载能力造成不利影响。除了应变率影响外，使用修改后的Steel02模型来考虑残余应力，可以很好地预测被测柱的整体响应。使用数值模型表明，应变硬化在预测柱塑料铰链中的局部应力-应变响应中起关键作用。在模型中应考虑应变率对钢屈服强度的影响，以更好地预测支撑框架的非弹性地震响应和稳定性。;进行了探索性非线性地震分析，以研究减小圆柱体尺寸的影响。按照容量设计原则设计的两层人字形支撑钢框架。即使发生柱屈曲，所检查的结构也可以承受设计的地面运动而不会崩溃。 （摘要由UMI缩短。）；开发了Rosenbrock-W集成方案，以最终执行涉及实验列屈曲的实时动态子结构（RTDS）实验。结果表明，通过考虑积分过程中涉及的雅可比矩阵中物理子结构的性质，可以提高该方案的性能，稳定性和准确性。所提出的方案被证明是无条件稳定的，二阶精确的，并且能够产生明确的位移和速度。在线性和非线性状态下的SDOF和MDOF系统上的RTDS实验表明，该方法可以轻松实现并在测试环境中按预期执行。这些测试还提供了机会，可以提出一种基于模式分解的新颖方法，以预测RTDS测试期间实验错误对整体响应的潜在不利影响。

著录项

  • 作者

    Lamarche, Charles-Philippe.;

  • 作者单位

    Ecole Polytechnique, Montreal (Canada).;

  • 授予单位 Ecole Polytechnique, Montreal (Canada).;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 298 p.
  • 总页数 298
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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