Seismic assessment and strengthening of 3D beam-column joints

3D梁柱节点的抗震评估和加固

• 批准号: 445697424
• 负责人: Dr.-Ing. Josipa Bosnjak
• 金额: --
• 依托单位: MPA Stuttgart, Otto-Graf-Institut (FMPA)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/445697424?language=en
• 关键词: Seismic; assessment; strengthening; 3D; beam

The primary goals of this project are (i) to develop practical and reliable models for realistic performance assessment of 3D beam-column joints of NSD structures while taking into account the influence of slabs and transverse beams, and (ii) to develop a low-invasive, high-effective strengthening solution for 3D beam-column joints and the corresponding models for their performance assessment. The existing research work has primarily been focused on the planar 2-dimensional beam-column joint sub-assemblies without considering the influence of transverse beams or slabs. Limited studies existing in literature clearly brought out the significant influence of slabs and transverse beam as well as bi-directional loading on the seismic performance of beam-column joints especially of NSD structures. For the strengthening of insufficient planar beam-column joints, fully fastened haunch retrofit solution (FFHRS) has been investigated by the applicant and other researchers and is shown to be a practically viable and effective strengthening method provided the fasteners used to connect the haunch element to the structural members perform well. The effectiveness of the retrofit solution is largely dependent on the relative stiffness of the connecting members, the haunch element and the stiffness of post-installed anchors. The participation of slab in a beam-column joint can significantly modify these relative stiffness values and therefore, the existing data on 2D joints is insufficient to develop a reliable strengthening solution. With the above-mentioned primary goals in sight, in this project, experimental investigations will be performed on full-scale beam-column joints to clearly and step-by-step bring out the influence of (i) transverse beam, (ii) monolithic slab, and (iii) bi-directional loading on the seismic performance of beam-column joints of NSD structures. Experiments will be augmented by a detailed numerical investigation and parametric study to quantify the influence of various parameters. Further experimental investigations on full-scale beam-column joints after strengthening using FFHRS will be carried out. However, tests will first be performed on anchorages under cyclic loading to: (i) identify the most suitable anchor type for connecting the haunch elements to frame members, and (ii) provide information on the load-displacement and hysteretic behavior of the anchors. A new displacement based protocol will be used for these tests. Based on the experimental and numerical investigations carried out within the framework of the project, multi-spring models will be developed that can be used for the performance assessment of as-built joints as well as the joints retrofitted with FFHRS while taking into account the influence of the slabs, transverse beam, bi-directional loading and anchorage behavior.

该项目的主要目标是（i）开发实用可靠的模型，用于 NSD 结构 3D 梁柱节点的实际性能评估，同时考虑板和横梁的影响；（ii）开发低侵入、高效的 3D 梁柱节点加固解决方案及其性能评估的相应模型。现有的研究工作主要集中在平面二维梁柱节点组件上，没有考虑横梁或板的影响。现有文献中有限的研究清楚地表明了板和横梁以及双向荷载对梁柱节点尤其是NSD结构的抗震性能的显着影响。对于不足的平面梁柱节点的加固，申请人和其他研究人员已经研究了完全紧固的腋部改造解决方案（FFHRS），并且证明，只要用于将腋部元件连接到结构构件的紧固件性能良好，它是一种实际可行且有效的加固方法。改造解决方案的有效性很大程度上取决于连接构件、腋部元件的相对刚度以及后安装锚固件的刚度。梁柱节点中板的参与可以显着改变这些相对刚度值，因此，二维节点的现有数据不足以开发可靠的加固解决方案。围绕上述主要目标，本项目将对梁柱节点进行足尺试验研究，逐步明确横梁、整体板、双向荷载对NSD结构梁柱节点抗震性能的影响。实验将通过详细的数值研究和参数研究来增强，以量化各种参数的影响。使用 FFHRS 加固后的全尺寸梁柱节点将进行进一步的实验研究。然而，首先将在循环载荷下对锚固进行测试，以：（i）确定将腋元件连接到框架构件的最合适的锚类型，以及（ii）提供有关锚的载荷位移和迟滞行为的信息。这些测试将使用新的基于位移的协议。基于该项目框架内进行的实验和数值研究，将开发多弹簧模型，可用于竣工节点以及采用 FFHRS 改造的节点的性能评估，同时考虑板、横梁、双向载荷和锚固行为的影响。