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首页> 外文学位 >Investigation of rectangular concrete columns reinforced or prestressed with fiber reinforced polymer (FRP) bars or tendons.
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Investigation of rectangular concrete columns reinforced or prestressed with fiber reinforced polymer (FRP) bars or tendons.

机译：研究了用纤维增强聚合物（FRP）筋或腱加固或预应力的矩形混凝土柱。

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摘要

Fiber reinforced polymer (FRP) composites have been increasingly used in concrete construction. This research focused on the behavior of concrete columns reinforced with FRP bars, or prestressed with FRP tendons. The methodology was based the ultimate strength approach where stress and strain compatibility conditions and material constitutive laws were applied.;Axial strength-moment (P-M) interaction relations of reinforced or prestressed concrete columns with FRP, a linearly-elastic material, were examined. The analytical results identified the possibility of premature compression and/or brittle-tension failure occurring in FRP reinforced and prestressed concrete columns where sudden and explosive type failures were expected. These failures were related to the rupture of FRP rebars or tendons in compression and/or in tension prior to concrete reaching its ultimate strain and strength. The study also concluded that brittle-tension failure was more likely to occur due to the low ultimate tensile strain of FRP bars or tendons as compared to steel. In addition, the failures were more prevalent when long term effects such as creep and shrinkage of concrete, and creep rupture of FRP were considered. Barring FRP failure, concrete columns reinforced with FRP, in some instances, gained significant moment resistance. As expected the strength interaction of slender steel or FRP reinforced concrete columns were dependent more on column length rather than material differences between steel and FRP.;Current ACI minimum reinforcement ratio for steel (rhomin) reinforced concrete columns may not be adequate for use in FRP reinforced concrete columns. Design aids were developed in this study to determine the minimum reinforcement ratio (rhof,min) required for rectangular reinforced concrete columns by averting brittle-tension failure to a failure controlled by concrete crushing which in nature was a less catastrophic and more gradual type failure. The proposed method using rhof,min enabled the analysis of FRP reinforced concrete columns to be carried out in a manner similar to steel reinforced concrete columns since similar provisions in ACI 318 were consistently used in developing these aids. The design aids produced accurate estimates of rhof,min. When creep and shrinkage effects of concrete were considered, conservative rhof,min values were obtained in order to preserve an adequate margin of safety due to their unpredictability.
机译：纤维增强聚合物（FRP）复合材料已越来越多地用于混凝土建筑中。这项研究的重点是用FRP筋加固或用FRP筋预应力的混凝土柱的性能。该方法基于极限强度方法，其中应用了应力和应变相容性条件以及材料本构关系。研究了钢筋混凝土或预应力混凝土柱与线弹性材料FRP的轴向强度-矩（P-M）相互作用关系。分析结果确定了在FRP加固和预应力混凝土柱中可能发生过早的压缩和/或脆性-拉伸破坏的可能性，这些区域可能会发生突然和爆炸性的破坏。这些失败与FRP钢筋或钢筋在混凝土达到其极限应变和强度之前的受压和/或拉力断裂有关。研究还得出结论，与钢相比，由于FRP筋或钢筋的极限拉伸应变低，因此更有可能发生脆性拉伸破坏。此外，考虑到混凝土的蠕变和收缩以及FRP的蠕变断裂等长期影响，这种破坏更为普遍。除非FRP失效，否则在某些情况下用FRP加固的混凝土柱具有明显的抗弯矩性。正如预期的那样，细长钢或FRP钢筋混凝土柱的强度相互作用更多地取决于柱长，而不是钢和FRP之间的材料差异。；钢（大黄粉）钢筋混凝土柱的当前ACI最小增强比可能不足以用于FRP钢筋混凝土柱。在这项研究中开发了设计辅助工具，通过将脆性拉伸破坏避免由混凝土压碎控制，从而确定矩形钢筋混凝土柱所需的最小钢筋比率（rhof，min），而自然压碎的破坏性较小，而逐步破坏性较大。所提出的使用rhof，min的方法使FRP钢筋混凝土柱的分析可以类似于钢钢筋混凝土柱的方式进行，因为在开发这些辅助工具时始终使用ACI 318中的类似规定。设计辅助工具可精确估算出rhof，min。当考虑混凝土的蠕变和收缩效应时，由于它们的不可预测性，因此获得了保守的rhof，min值，以保留足够的安全裕度。

著录项

  • 作者

    Choo, Ching Chiaw.;

  • 作者单位

    University of Kentucky.;

  • 授予单位 University of Kentucky.;
  • 学科 Engineering Civil.;Plastics Technology.;Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 158 p.
  • 总页数 158
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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