透過您的圖書館登入
IP:44.195.47.227
  • 學位論文

預力與非預力混凝土梁之剪力強度研究

Study on Shear Strength of Prestressed and Non-Prestressed Reinforced Concrete Beams

指導教授 : 黃世建
共同指導教授 : 徐增全
若您是本文的作者,可授權文章由華藝線上圖書館中協助推廣。

摘要


鋼筋混凝土梁之剪力強度預測歷史由來已久,時至今日,一般相信鋼筋混凝土梁中混凝土抗剪貢獻係分為剪力裂縫互鎖效應、壓力區範圍混凝土抗剪與主筋插筋效應三部分,但ACI 318-14 規範中對於混凝土剪力貢獻之主要來源仍有爭議。ACI 318-14認為,梁剪力裂縫互鎖機制為混凝土抗剪強度中之穩定來源,故剪力鋼筋設計時之降伏應力值須小於420MPa,此乃因避免剪力裂縫寬度過大,使剪力裂縫互鎖機制喪失之故。然徐增全等人,於2010與2014年分別提出預測預力混凝土(PC) 梁與鋼筋混凝土 (RC) 梁剪力強度之經驗公式。在混凝土剪力強度貢獻來源的認定上係認為混凝土梁壓力區為主要剪力強度貢獻來源,且對試體剪力預測結果具有合理之精確度。但此套公式,其物理含意與ACI-318規範有著本質上的差異。 有鑒於前述,在2015年,本系列研究規劃測試8支I形梁試體、8支矩形梁試體之剪力強度,本論文主要執行8支矩形梁試體之實驗測試。希望藉由施加預力改變,印證是否預力量會影響梁剪力強度,並探討混凝土剪力強度之貢獻來源及釐清I形梁翼版之抗剪貢獻,並歸納整合提出一套非預力梁與預力梁皆可適用之剪力強度預測公式。 綜合歸納本研究之實驗結果與參考前人之研究經驗發現,本論文確認混凝土主要抗剪來源為壓力區混凝土提供,且預力大小確實影響壓力區混凝土之抗剪強度。且I形梁之翼版以提供壓力區混凝土束制之方式參與抗剪。本研究提出之整合型梁剪力強度預測公式考量上述結果做為預測梁剪力強度之依據,使本研究之剪力強度預測公式能夠廣泛涵蓋矩形梁及I形梁,並統一RC梁與PC梁之剪力預測公式。

並列摘要


It’s commonly believed that the shear contribution from concrete consists of shear crack interlocking, concrete in compression zone and dowel action. However , there is still controversial about the major part of shear contribution from concrete. ACI 318-14 considers the major shear resistant from concrete is shear crack interlocking. So there is a specific restriction about the yielding strength of shear stirrup in ACI 318-14. Hsu et al. proposed two equations for predicting shear strength of PC beam and RC beam at 2010 and 2014 respectively. Hsu et al. considered the major shear resistant from concrete is concrete in compression zone. This research tested 8 I beams and 8 rectangular beams. By varying the effective pre-stress force on the specimens, this research want to clarify the effect of pre-stressed force on the shear strength. Also the effect of flange of I beam on the shear strength is investigated. According to the test results of this research and the existing finding from literature, this research concludes that the major shear resistant from concrete is concrete in compression zone and pre-stressed force does increase the shear strength. Also the flange of I beam can increase the shear strength of beam by providing well confinement to the compression zone. Finally this research proposes a new equation that can be used for both RC Beam and PC Beam for shear strength prediction.

參考文獻


[13] 陳憲宏,「部分預力普通強度混凝土I形梁之剪力強度研究」,碩士論文,國立台灣大學土木工程學系,台北,民國104年。
[3] ACI-ASCE Committee 426, “Shear Strength of Reinforced Concrete Members (ACI 426R-74) (Reapproved 1980),” Proceedings, ASCE, V. 99, No. ST6, June 1973, pp. 1148-1157.
[4] ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14),” American Concrete Institute, Farmington Hills, Mich., 2014, 519 pp.
[5] Fenwick, R. C., and Paulay, T., “Mechanisms of Shear Resistance of Concrete Beams,” Journal of Structural Division, ASCE, Vol. 94, ST10, October 1968, pp. 2235-2350.
[6] Taylor, H. P. J., “Investigation of the Forces Carried Across Cracks in Reinforced Concrete Beams in Shear by Interlock of Aggregate,” Cement and Concrete Association, London, TRA42.447, 1970, 22 pp.

延伸閱讀