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首页> 外文学位 >Finite Element Modeling of Pretensioned Concrete Girders: A Methodological Approach with Applications in Large Strands and End Zone Cracking.
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Finite Element Modeling of Pretensioned Concrete Girders: A Methodological Approach with Applications in Large Strands and End Zone Cracking.

机译：预应力混凝土梁的有限元建模：一种在大钢绞线和端部开裂中应用的方法学方法。

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摘要

Two issues pertaining to the current state of pretensioning industry are investigated in this research: spacing of 0.7-in. diameter strands and effectiveness of end zone reinforcing details.;Given the current economic constraints and the limitation of testing facilities, there is a great need for reliable and unified methodological approaches for simulation of the behavior of pretensioned concrete members to complement experimental investigations. Therefore, two finite element techniques are evaluated: extrusion and embedment techniques. Once the techniques are verified and validated against closed form solutions and experimental data, respectively, they are utilized for analytical purposes of this research.;Extrusion technique is utilized to show that 0.7-in. diameter strands can be potentially spaced at reduced spacing of 2-in. on center under certain conditions including minimum concrete compressive strength of 10,000 psi at the time of release.;Embedment technique is utilized for comparative investigation of four end zone reinforcing details: AASHTO LRFD , NCHRP Report 654, Illinois and combined AASHTO-Illinois details. The research indicates that NCHRP Report 654 offers an optimum end zone remedial scheme for typical AASHTO/PCI bulb-tee girders. Without requiring any additional reinforcement in comparison to AASHTO LRFD, it results in fabrication-friendly rebar spacing.;Finally, eight Washington WF100 Super-girders are instrumented and investigated for potential end zone cracking as part of the Alaskan Viaduct Project in the state of Washington. Each girder is 100 in. deep and over 200 ft long among the largest precast girders in North America at the time of this research. The instrumentation set-up is intended for on-site collection of strain data at the end zone reinforcing bars and the 0.6-in. diameter strands. The experimental observations indicate that the response of the super-girders at release is similar to other I-girders commonly used in practice. In addition, all eight girders experienced different levels of end zone cracking most severely along the web-bottom flange interface.;A new closed-form solution is proposed and validated against the experimental results, based on the shear-friction theory to estimate the tensile cracking at the web-bottom flange interface of precast I-girders immediately after the release of pretensioning.
机译：本研究调查了与预张紧行业的现状有关的两个问题：间距为0.7英寸。考虑到当前的经济限制和测试设备的局限性，迫切需要一种可靠且统一的方法来模拟预张混凝土构件的性能，以补充实验研究。因此，评估了两种有限元技术：挤压和嵌入技术。一旦分别针对封闭形式的解决方案和实验数据对技术进行了验证和验证，就将其用于本研究的分析目的。挤压技术用于显示0.7英寸。直径的股可能会以2英寸的减小间距隔开。在某些条件下，包括在释放时混凝土的最小抗压强度为10,000 psi的情况下，在中心处进行；嵌入技术用于比较研究四个端部区域的钢筋细节：AASHTO LRFD，NCHRP Report 654，伊利诺伊州和AASHTO-Illinois的综合细节。研究表明，NCHRP报告654为典型的AASHTO / PCI灯泡T形梁提供了最佳的端部补救方案。与AASHTO LRFD相比，不需要任何额外的加固，它可以使制造过程中的钢筋间距更小。最后，作为华盛顿州阿拉斯加高架桥项目的一部分，对8台华盛顿WF100超级梁进行了仪器检测，并研究了潜在的端部区域开裂。 。在进行这项研究时，在北美最大的预制梁中，每个梁的深度为100英寸，长超过200英尺。仪器设置旨在在端部区域钢筋和0.6英寸处现场采集应变数据。直径股。实验观察表明，超级大梁在释放时的响应与实践中常用的其他工字梁相似。此外，所有八个大梁沿腹板-底部翼缘交界处的端部区域开裂程度最高。;基于剪切摩擦理论估算拉力，提出了一种新的封闭形式的解决方案，并针对实验结果进行了验证释放预应力后立即在预制工字钢的腹板-底部翼缘界面处开裂。

著录项

  • 作者

    Arab, Amir A.;

  • 作者单位

    The George Washington University.;

  • 授予单位 The George Washington University.;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 596 p.
  • 总页数 596
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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