设防框架的梁铰模型和能力易损性的试验研究

EXPERIMENTAL STUDY ON THE BEAM HINGE MODEL AND CAPACITY FRAGILITY OF FORTIFIED FRAMES

抗震设防等级越高,建筑物的抗震能力越强。然而反映设防能力区别的实用力学模型及其参数却很少。该研究即通过试验得到RC框架梁的塑性铰的本构模型及概率能力,为整体结构的地震风险研究奠定基础。为此,制作了4组12个基于GB50011-2010不同设防等级和位置的节点缩尺模型并做了拟静力试验。结果表明,节点的破坏实质是梁的受弯破坏,节点所在位置对梁的受力变形指标影响不大。因此,较少的试验试件可得到扩充数倍的梁铰样本,提高概率分析精度。因此,基于试验的统计结果并参照FEMA 356,提炼了不同设防等级的梁的塑性铰归一化本构模型,提出了梁铰破坏程度的性能指标,计算了梁的概率抗震能力,总结了设防能力和易损性的级差。用试验的方法量化结构模型的规范要求并赋予模型指标可靠度,是该文的创新点。

Higher seismic fortification grades require higher seismic capacity of the building. However, mechanical models and parameters that can reflect fortification capacity differences are limited in practice. This study aims to obtain the constitutive models and probabilistic capacities of RC frame beam hinges from tests, which is important for the seismic risk study of the whole structure. For this purpose, 4 groups with 12 reduced scale joint models that conform to GB50011-2010 with different fortification levels and locations were made and subjected to pseudo-static tests. The test results showed that failure of joints was essentially bending failure of beams; the locations of joints did not influence the strength and deformation indices of beams. Therefore, the number of beam hinge samples could be expanded several times from limited test specimen, which increased the precision of probability analyses. Thus, based on statistical results and with reference to FEMA 356, beam hinge models of different fortification levels were extracted; performance indices to different damage states were proposed; model parameter reliabilities were calculated; and fortification gradients and fragility gradients were summarized. Quantifying structural models by the code requirements while assigning the model parameters with reliabilities by means of structural tests are the main innovation of this study.