高強度I形部分預力混凝土梁之剪力強度研究

Study on the Shear Strength of Partially Prestressed High Strength Concrete I Beams

黃青龍(Hoang Thanh Long)

指導教授 ： 黃世建 ； 徐增全

國立臺灣大學/工學院/土木工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01198

摘要

無資料

關鍵字

高強度 ； 分預力 ； 混凝土

並列摘要

Partial prestressing, which fills the gap between fully prestressed concrete and reinforced concrete, has now been accepted and becomes common practice in many countries. Partial prestressing has now been recognized as an intermediate case between full prestressing and conventional (nonprestressed) reinforcing. Compared with fully prestressed concrete (FPC) structures, adoption of partial prestressing may result in increased ductility and energy absorption capacity, improved economy, as well as reduction of the camber and creep deformation due to prestress. This research aims to solve one of the most troublesome problems in partially prestressed concrete (PPC) beam, namely the shear problem. In fact, there is no rational model at present to predict the shear behavior of prestressed concrete structures and the strength of shear failures. Although there were a lot of studies and researches about shear strength in FPC beams but not much research about PPC beams in the world. Because of this deficiency, all the shear design provisions, such as those in the ACI 318-14 [1] and AASHTO LRFD Specification- 2012 [2], are empirical, complicated and have severe limitations. In this research, four full- scale prestressed high strength concrete I-beams were tested to study the effect of number of prestressing tendons and amounts of flexural nonprestressed steel. The cross section, web reinforcement, flexural ultimate moment, and shear span ratio (a/d) were held constants. The numbers of prestressing tendons and amounts of non-prestressed tensile were varied. The prestressing factor was defined by this equation: . Ap and As are the cross sectional areas of prestressed steel and non-prestressed tensile steel; and are the yield strength of prestressed steel and non-prestressed tensile steel. The results from these tests, together with those found in literature, were used to help the engineers have an overview about the behavior of shear strength in partially prestressed high strength concrete beam.

並列關鍵字

Shear strength ； partially prestressed concrete beam ； high strength concrete

參考文獻

[1] ACI Committee 318 (2014), “Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14),” American Concrete Institute, Farmington Hills, MI.

[4] Laskar, A.; Hsu T. T. C.; and Mo, Y. L.,“Shear Strengths of Prestressed Concrete Beams Part 1:Experiments and Shear Design Equations,”ACI Structural Journal, V. 107, No.3, May-June 2010, pp.330-339.

[5] Hsu, T. T. C.; Laskar, A.; and Mo, Y. L., “Shear Strengths of Prestressed Concrete Beams Part 2: Comparisons with ACI and AASHTO Provisions,”ACI Structural Journal, V. 107, No.3, May-June 2010, pp.340-345.

[6] Lyngberg, B. S.,“Ultimate Shear Resistance of Partially Prestressed Reinforced Concrete I-Beams,”ACI JOURNAL, Proceedings V. 73, No.4, Apr. 1976, pp. 214-222.

[8] Kuo, W. W.; Hsu T. T. C.; and Hwang S. J.,“Shear Strength of Reinforced Concrete Beams,”ACI Structural Journal, V. 111, No.4, July-August 2014.