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Structural Behavior of Full Scale Totally Precast Concrete Counterfort Retaining Wall System

机译：全尺寸全预制混凝土防撞墙结构性能

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摘要

Totally Prefabricated Concrete Counterfort Retaining Wall (TPCCRW) provides an alternative for conventional construction techniques to reduce the drawbacks associated with cast-in-place construction. TPCCRW is composed of a precast concrete wall component (face panel and counterforts) and a base slab connected, on-site, through headed anchors. The anchors extend downward from the counterforts into shear pockets located in the precast base slab. While the structural design of TPCCRW shares some features with cast-in place systems, it also has specific requirements for anchor connections, strength of shear pockets, and counterfort design. The design of TPCCRW was developed according to AASHTO LRFD (2012) specifications and compared to an existing cast-in-place counterfort system in Chicago, IL, for both structural and economic performances. The design strength of TPCCRW (moment and shear) surpassed that of the existing system with an overall reduction in concrete volume of 57%. A parametric study identified a counterfort spacing-to-base length ratio of 0.35 and a counterfort extension-to-heel length ratio of 0.6 as optimal values.;In addition, the overall structural behavior of TPCCRW was examined experimentally and analytically using Nonlinear Finite Element Analysis (NLFEA). A full scale prototype (20 ft 2 in. high and 13 ft 10 in. wide) was designed meeting the requirements of AASHTO LRFD specifications, assembled, constructed, instrumented and tested at the precast concrete plant. The design was optimized and validated using NLFEA. The precast components were connected through five headed anchors at each counterfort. The results showed that the wall experienced a deflection of 0.2 in. at its middle. The anchors succeeded to maintain serviceability and ultimate strength requirements. The proposed system required a unique method of construction. Therefore, the fabrication and construction procedures and guidelines required to accelerate the erection process on site were detailed. The system components can be fully assembled and set in place in less than 2 hours.;Finally, the pullout behavior of headed anchors used in TPCCRW was examined experimentally and analytically using NLFEA. Eighteen precast concrete blocks (21 in. x 20 in.) having a truncated shear pocket identical to those used in TPCCRW were prepared, grouted with headed anchors, instrumented, and experimentally tested. The study took into consideration two different block thicknesses (14 in. and 6 in.), two IDOT certified types of headed anchors and types of concrete grout, different bar sizes (#6, #7, #8, #9), and different embedment depths (12.5 in., 10 in., 8 in, and 6 in.). The structural behavior of the pullout specimens was characterized by yielding and fracture of steel anchors regardless of their size. Concrete breakout was witnessed in 14 in. thick concrete specimens made with #9 headed anchors and 6 in. embedment depth when the specimen was tested to ultimate. The experimental test results were verified using finite element analysis and compared to design codes and other studies in the literature. The result showed close correlation with the AISC design guide for base plates and headed rods.
机译：完全预制的混凝土防撞墙（TPCCRW）为常规施工技术提供了一种替代方案，可减少现浇施工带来的弊端。 TPCCRW由预制混凝土墙构件（面板和反作用墙）和基础板组成，这些板通过有头锚固在现场连接。锚从反作用力向下延伸到位于预制基础板中的剪切袋中。 TPCCRW的结构设计与现浇系统具有某些功能，但对锚固连接，剪力袋的强度和反作用设计也有特定要求。 TPCCRW的设计是根据AASHTO LRFD（2012）规范开发的，并与伊利诺伊州芝加哥市的现有现场浇筑的对撞系统进行了比较，以了解其结构和经济性能。 TPCCRW（弯矩和剪力）的设计强度超过了现有系统，混凝土体积总体减少了57％。一项参数化研究确定了平衡力的间距与底座的长度之比为0.35和平衡力的延伸杆与脚跟的长度之比为0.6为最佳值;此外，使用非线性有限元对TPCCRW的整体结构行为进行了实验和分析分析（NLFEA）。设计了一个完整的原型（高20英尺2英寸，宽13英尺10英寸），以满足AASHTO LRFD规范的要求，并在预制混凝土工厂进行了组装，构造，测试和测试。使用NLFEA对设计进行了优化和验证。在每次反抗时，预制组件通过五个带头的锚连接。结果表明，墙的中间变形为0.2 in.。这些锚成功地满足了维修性和极限强度的要求。拟议的系统需要一种独特的构造方法。因此，详细说明了加快现场安装过程所需的制造和施工程序以及指南。系统组件可以在不到2小时的时间内完全组装好并安装到位。最后，使用NLFEA对TPCCRW中使用的带头锚栓的拉拔性能进行了实验和分析。制备了18个预制的混凝土砌块（21英寸x 20英寸），该砌块具有与TPCCRW中使用的截断剪切袋相同的截断剪切袋，并用带头锚固剂灌浆，进行了仪器测试和实验测试。该研究考虑了两种不同的砌块厚度（14英寸和6英寸），两种IDOT认证的带头锚栓类型和混凝土灌浆的类型，不同的钢筋尺寸（＃6，＃7，＃8，＃9）和不同的嵌入深度（12.5英寸，10英寸，8英寸和6英寸）。不论尺寸如何，拉拔试样的结构行为均以钢锚的屈服和断裂为特征。在测试样品至极限时，在14英寸厚的混凝土样品中发现了混凝土破裂，该样品由＃9头锚和6英寸的埋深制成。实验测试结果使用有限元分析进行了验证，并与设计规范和文献中的其他研究进行了比较。结果显示与AISC设计指南有关的底板和有头杆密切相关。

著录项

  • 作者

    Farhat, Maen.;

  • 作者单位

    University of Illinois at Chicago.;

  • 授予单位 University of Illinois at Chicago.;
  • 学科 Civil engineering.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 188 p.
  • 总页数 188
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 遥感技术;
  • 关键词

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