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

機譯：全尺寸全預制混凝土防撞墻結構性能

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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.
機譯：完全預制的混凝土防撞墻（TPCCRW）為常規(guī)施工技術提供了一種替代方案，可減少現(xiàn)澆施工帶來的弊端。 TPCCRW由預制混凝土墻構件（面板和反作用墻）和基礎板組成，這些板通過有頭錨固在現(xiàn)場連接。錨從反作用力向下延伸到位于預制基礎板中的剪切袋中。 TPCCRW的結構設計與現(xiàn)澆系統(tǒng)具有某些功能，但對錨固連接，剪力袋的強度和反作用設計也有特定要求。 TPCCRW的設計是根據(jù)AASHTO LRFD（2012）規(guī)范開發(fā)的，并與伊利諾伊州芝加哥市的現(xiàn)有現(xiàn)場澆筑的對撞系統(tǒng)進行了比較，以了解其結構和經(jīng)濟性能。 TPCCRW（彎矩和剪力）的設計強度超過了現(xiàn)有系統(tǒng)，混凝土體積總體減少了57％。一項參數(shù)化研究確定了平衡力的間距與底座的長度之比為0.35和平衡力的延伸桿與腳跟的長度之比為0.6為最佳值;此外，使用非線性有限元對TPCCRW的整體結構行為進行了實驗和分析分析（NLFEA）。設計了一個完整的原型（高20英尺2英寸，寬13英尺10英寸），以滿足AASHTO LRFD規(guī)范的要求，并在預制混凝土工廠進行了組裝，構造，測試和測試。使用NLFEA對設計進行了優(yōu)化和驗證。在每次反抗時，預制組件通過五個帶頭的錨連接。結果表明，墻的中間變形為0.2 in.。這些錨成功地滿足了維修性和極限強度的要求。擬議的系統(tǒng)需要一種獨特的構造方法。因此，詳細說明了加快現(xiàn)場安裝過程所需的制造和施工程序以及指南。系統(tǒng)組件可以在不到2小時的時間內(nèi)完全組裝好并安裝到位。最后，使用NLFEA對TPCCRW中使用的帶頭錨栓的拉拔性能進行了實驗和分析。制備了18個預制的混凝土砌塊（21英寸x 20英寸），該砌塊具有與TPCCRW中使用的截斷剪切袋相同的截斷剪切袋，并用帶頭錨固劑灌漿，進行了儀器測試和實驗測試。該研究考慮了兩種不同的砌塊厚度（14英寸和6英寸），兩種IDOT認證的帶頭錨栓類型和混凝土灌漿的類型，不同的鋼筋尺寸（＃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）。不論尺寸如何，拉拔試樣的結構行為均以鋼錨的屈服和斷裂為特征。在測試樣品至極限時，在14英寸厚的混凝土樣品中發(fā)現(xiàn)了混凝土破裂，該樣品由＃9頭錨和6英寸的埋深制成。實驗測試結果使用有限元分析進行了驗證，并與設計規(guī)范和文獻中的其他研究進行了比較。結果顯示與AISC設計指南有關的底板和有頭桿密切相關。

著錄項

  • 作者

    Farhat, Maen.;

  • 作者單位

    University of Illinois at Chicago.;

  • 授予單位 University of Illinois at Chicago.;
  • 學科 Civil engineering.
  • 學位 Ph.D.
  • 年度 2016
  • 頁碼 188 p.
  • 總頁數(shù) 188
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 遙感技術;
  • 關鍵詞

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