Performance of externally bonded fiber-reinforced polymer retrofits in the 2018 Cook Inlet Earthquake in Anchorage, Alaska
Performance of externally bonded fiber-reinforced polymer retrofits in the 2018 Cook Inlet Earthquake in Anchorage, Alaska
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DOI：
10.1177/87552930211028609
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发表时间：
2021-08
影响因子：
5
通讯作者：
J. Tatar;S. Sattar;David Goodwin;S. Milev;Shafique Ahmed;J. Dukes;C. Segura
中科院分区：
文献类型：
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作者：
J. Tatar;S. Sattar;David Goodwin;S. Milev;Shafique Ahmed;J. Dukes;C. Segura
作为提高阿拉斯加州（AK）建筑物抗震性能的努力的一部分，对阿拉斯加州安克雷奇的许多缺陷结构进行了改造，其中一些采用了外部粘结纤维增强聚合物（EBFRP）复合材料系统。2018年库克湾7.1级地震影响了同一地区，这为评估EBFRP加固在相对高强度地震中的性能提供了机会。本研究总结了该现场调查的以下结果：（1）库克湾地震中EBFRP加固结构的性能，以及（2）在亚北极环境中暴露十多年的FRP加固条件的观察结果。美国国家标准与技术研究院（NIST）的部署团队与特拉华州大学（UD）复合材料中心合作，对多座建筑物的EBFRP改造进行了地震后检查，以评估其在地震期间的性能和老化条件。EBFRP剥离记录与红外热成像和声学测深和EBFRP与混凝土之间的粘结质量进行了评估，使用拉脱试验。目视检查显示，经EBFRP改装的部件没有重大地震损坏迹象。然而，剥离和拔出试验结果的评估表明，室外条件可能导致EBFRP和混凝土之间的粘结劣化，原因包括安装缺陷随时间推移而增加、FRP/混凝土界面处存在的水分引起的冻融膨胀、材料热膨胀差异或其组合。碳纤维增强聚合物（CFRP）粘结到混凝土被认为是更容易受到室外暴露比玻璃纤维增强聚合物（GFRP）债券。由于缺乏基线数据，无法评估地震对FRP/混凝土粘结的影响。
As part of the effort to improve the seismic performance of buildings in Alaska (AK), many of the deficient structures in Anchorage, AK, were retrofitted—some with externally bonded fiber-reinforced polymer (EBFRP) composite systems. The 2018 magnitude 7.1 Cook Inlet earthquake that impacted the same region offered an opportunity to evaluate the performance of EBFRP retrofits in a relatively high-intensity earthquake. This study summarizes the following findings of this field investigation: (1) the performance of EBFRP-retrofitted structures in the Cook Inlet earthquake and (2) the observations concerning the condition of FRP retrofits from over a decade of exposure in a subarctic environment. A deployment team from the National Institute of Standards and Technology (NIST) in collaboration with the University of Delaware (UD) Center for Composite Materials conducted post-earthquake inspections of EBFRP retrofits in multiple buildings to assess their performance during the earthquake and condition with respect to weathering. EBFRP debonding was documented with infrared thermography and acoustic sounding and the bond quality between EBFRP and concrete was assessed using pull-off tests. Visual inspections showed no major signs of earthquake damage in the EBFRP-retrofitted components. However, evaluation of debonding and pull-off test results suggested that outdoor conditions may have led to bond deterioration between EBFRP and concrete from installation defects that grew over time, freeze–thaw expansion from moisture present at the FRP/concrete interface, differences in thermal expansion of the materials, or a combination thereof. The carbon fiber–reinforced polymer (CFRP) bond to concrete was found to be more vulnerable to outdoor exposure than the glass fiber–reinforced polymer (GFRP) bond. Earthquake effects on FRP/concrete bond could not be assessed due to the lack of baseline data.