考虑尺寸效应的深受弯构件受剪模型分析
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摘要
深受弯构件斜截面受剪机理复杂且受尺寸效应影响显著,缺乏准确、合理的受剪计算模型。结合Tan-Cheng模型中对混凝土软化作用和深受弯构件尺寸效应的全面考虑优势,在深入研究混凝土斜压杆倾角α和构件复合抗拉强度f_t对深受弯构件受剪承载力影响的基础上,简化压杆顶部节点区高度l_c与α的关系,考虑腹筋有效作用区域修正复合抗拉强度_ft计算模型,提出了不影响精度前提下的修正Tan-Cheng模型。研究表明:基于国内外308组深受弯构件受剪试验数据计算结果,建议模型计算精度等同Tan-Cheng模型,并能够准确考虑尺寸效应影响,但计算过程较为简洁;通过与现有典型各国规范建议模型对比分析表明,计算结果较规范计算值更接近试验值,能够更准确地对深受弯构件的受剪承载力进行预测。
There is a lack of accurate and reasonable shear design models for reinforced concrete deep flexural members such as typical D-region shear components with complicated force mechanism and significant size effect. In combination with the advantages of the Tan-Cheng model that fully considers the softening effect of concrete and the size effect of struts, and on the basis of the deep understanding of the effect of diagonal strut angle α and composite tensile stress f_t on the shear strength of deep flexural members, the relationship between the top node height l_c and α was simplified and a modified Tan-Cheng model was proposed by reconsidering the effective action region of web reinforcement. The predictions of 308 deep flexural members from either foreign or domestic source indicate that the proposed model has a comparable accuracy with the Tan-Cheng model, and it can accurately consider the size effect of concrete struts through a concise calculation process. The comparison between the proposed model and current code provisions shows that the predictions by the proposed model has a better agreement with the test results. It further indicates that the proposed model can reasonably predict the shear strength of deep flexural members.
There is a lack of accurate and reasonable shear design models for reinforced concrete deep flexural members such as typical D-region shear components with complicated force mechanism and significant size effect. In combination with the advantages of the Tan-Cheng model that fully considers the softening effect of concrete and the size effect of struts, and on the basis of the deep understanding of the effect of diagonal strut angle α and composite tensile stress f_t on the shear strength of deep flexural members, the relationship between the top node height l_c and α was simplified and a modified Tan-Cheng model was proposed by reconsidering the effective action region of web reinforcement. The predictions of 308 deep flexural members from either foreign or domestic source indicate that the proposed model has a comparable accuracy with the Tan-Cheng model, and it can accurately consider the size effect of concrete struts through a concise calculation process. The comparison between the proposed model and current code provisions shows that the predictions by the proposed model has a better agreement with the test results. It further indicates that the proposed model can reasonably predict the shear strength of deep flexural members.
引文
[1]ACI Committee 318:Building code requirement for structural concrete(ACI 318-14)and commentary[S].American Concrete Institute,2014.
[2]CSA A23.3-04,Design of concrete structures[S].Canadian Standards Association,2004.
[3]The European Standard EN 1992-1-1:2004,Eurocode 2.Design of concrete structures[S].British Standards Institution,2004.
[4]Kani G N J.How safe are our large reinforced concrete beams?[C]//ACI Journal Proceedings,1967,64(3):128-141.
[5]Bazant Z P,Kazemi M T.Size effect on diagonal shear failure of beams without stirrups[J].ACI Structural Journal,1991,88(3):268-276.
[6]Collins M,Kuchma D.How safe are our large,lightly reinforced concrete beams,slabs,and footings?[J].ACIStructural Journal,1999,96(4):482-490.
[7]Tan K H,Lu H Y.Shear behavior of large reinforced concrete deep beams and code comparisons[J].ACIStructural Journal,1999,96(5):836-845.
[8]Matsuo M,Lertsrisakulrat T,Yanagawa A,et al.Shear behavior in RC deep beams with stirrups[J].Transactions of the Japan Concrete Institute,2002,23(5):385-390.
[9]Birrcher D B,Tuchscherer R G,Huizinga M,et al.Depth effect in deep beams[J].ACI Structural Journal,2014,111(4):731-740.
[10]Tan K H,Tong K,Tang C Y.Direct strut-and-tie model for prestressed deep beams[J].Journal of Structural Engineering,ASCE,2001,127(9):1076-1084.
[11]Tan K H,Cheng G H.Size effect on shear strength of deep beams:Investigating with strut-and-tie model[J].Journal of Structural Engineering,ASCE,2006,132(5):673-685.
[12]Kim J K,Yi S T,Park C K,Eo S H.Size effect on compressive strength of plain and spirally reinforced concrete cylinders[J].ACI Structural Journal,1999,96(1):88-94.
[13]Matamoros A B,Wong K H.Design of simply supported deep beams using strut-and-tie models[J].ACIStructural Journal,2003,100(6):704-712.
[14]GB50010-2010,混凝土结构设计规范[S].北京:中国建筑工业出版社,2010.GB50010-2010,Code for design of concrete structures[S].Beijing:China Architectural&Building Press,2010.(in Chinese)
[15]Smith K N,Vantsiotis A S.Shear strength of deep beams[J].ACI Structural Journal,1982,79(3):201-213.
[16]Kong F K,Robins P J,Cole D F.Web reinforcement effects on deep beams[C]//ACI Journal Proceedings.1970,67(12):1010-1018.
[17]Clark A P.Diagonal tension in reinforced concrete beams[C]//ACI Journal Proceedings,1951,48(10):145-156.
[18]Gardoni P,Der Kiureghian A,Mosalam K M.Probabilistic capacity models and fragility estimates for reinforced concrete columns based on experimental observations[J].Journal of Engineering Mechanics,ASCE,2002,128(10):1024-1038.
[19]Aguilar G,Matamoros A B,Parra-Montesinos G J,et al.Experimental evaluation of design procedures for shear strength of deep reinforced concrete beams[J].ACIStructural Journal,2002,99(4):539-548.
[20]Quintero-Febres C G,Parra-Montesinos G,Wight J K.Strength of struts in deep concrete members designed using strut-and-tie method[J].ACI Structural Journal,2006,103(4):577-586.
[21]Tan K H,Tang C Y,Tong K.Shear strength predictions of pierced deep beams with inclined web reinforcement[J].Magazine of Concrete Research,2004,56(8):443-452.
[22]Subedi N K,Vardy A E,Kubotat N.Reinforced concrete deep beams some test results[J].Magazine of Concrete Research,1986,38(137):206-219.
[23]Ramakrishnan V,Ananthanarayana Y.Ultimate strength of deep beams in shear[C]//ACI Journal Proceedings,1968,65(2):87-98.
[24]刘立新,谢丽丽,陈萌.钢筋混凝土深受弯构件受剪性能的研究[J].建筑结构,2000,30(10):19-22.Liu Lixin,Xie Lili,Chen Meng.The shear strength capability of reinforced concrete deep flexural members[J].Building Structure,2000,30(10):19-22.(in Chinese)
[25]龚绍熙.钢筋混凝土深梁在对称集中荷载下抗剪强度的研究[J].郑州工学院学报,1982,1:52-68.Gong Shaoxi.The shear strength capability of reinforced concrete deep beam under symmetric concentrated loads[J].Journal of Zhengzhou Technology Institute,1982,1:52-68.(in Chinese)
[26]Walravena J,Lehwalter N.Size effects in short beams loaded in shear[J].ACI Structural Journal,1994,91(5):585-593.
[2]CSA A23.3-04,Design of concrete structures[S].Canadian Standards Association,2004.
[3]The European Standard EN 1992-1-1:2004,Eurocode 2.Design of concrete structures[S].British Standards Institution,2004.
[4]Kani G N J.How safe are our large reinforced concrete beams?[C]//ACI Journal Proceedings,1967,64(3):128-141.
[5]Bazant Z P,Kazemi M T.Size effect on diagonal shear failure of beams without stirrups[J].ACI Structural Journal,1991,88(3):268-276.
[6]Collins M,Kuchma D.How safe are our large,lightly reinforced concrete beams,slabs,and footings?[J].ACIStructural Journal,1999,96(4):482-490.
[7]Tan K H,Lu H Y.Shear behavior of large reinforced concrete deep beams and code comparisons[J].ACIStructural Journal,1999,96(5):836-845.
[8]Matsuo M,Lertsrisakulrat T,Yanagawa A,et al.Shear behavior in RC deep beams with stirrups[J].Transactions of the Japan Concrete Institute,2002,23(5):385-390.
[9]Birrcher D B,Tuchscherer R G,Huizinga M,et al.Depth effect in deep beams[J].ACI Structural Journal,2014,111(4):731-740.
[10]Tan K H,Tong K,Tang C Y.Direct strut-and-tie model for prestressed deep beams[J].Journal of Structural Engineering,ASCE,2001,127(9):1076-1084.
[11]Tan K H,Cheng G H.Size effect on shear strength of deep beams:Investigating with strut-and-tie model[J].Journal of Structural Engineering,ASCE,2006,132(5):673-685.
[12]Kim J K,Yi S T,Park C K,Eo S H.Size effect on compressive strength of plain and spirally reinforced concrete cylinders[J].ACI Structural Journal,1999,96(1):88-94.
[13]Matamoros A B,Wong K H.Design of simply supported deep beams using strut-and-tie models[J].ACIStructural Journal,2003,100(6):704-712.
[14]GB50010-2010,混凝土结构设计规范[S].北京:中国建筑工业出版社,2010.GB50010-2010,Code for design of concrete structures[S].Beijing:China Architectural&Building Press,2010.(in Chinese)
[15]Smith K N,Vantsiotis A S.Shear strength of deep beams[J].ACI Structural Journal,1982,79(3):201-213.
[16]Kong F K,Robins P J,Cole D F.Web reinforcement effects on deep beams[C]//ACI Journal Proceedings.1970,67(12):1010-1018.
[17]Clark A P.Diagonal tension in reinforced concrete beams[C]//ACI Journal Proceedings,1951,48(10):145-156.
[18]Gardoni P,Der Kiureghian A,Mosalam K M.Probabilistic capacity models and fragility estimates for reinforced concrete columns based on experimental observations[J].Journal of Engineering Mechanics,ASCE,2002,128(10):1024-1038.
[19]Aguilar G,Matamoros A B,Parra-Montesinos G J,et al.Experimental evaluation of design procedures for shear strength of deep reinforced concrete beams[J].ACIStructural Journal,2002,99(4):539-548.
[20]Quintero-Febres C G,Parra-Montesinos G,Wight J K.Strength of struts in deep concrete members designed using strut-and-tie method[J].ACI Structural Journal,2006,103(4):577-586.
[21]Tan K H,Tang C Y,Tong K.Shear strength predictions of pierced deep beams with inclined web reinforcement[J].Magazine of Concrete Research,2004,56(8):443-452.
[22]Subedi N K,Vardy A E,Kubotat N.Reinforced concrete deep beams some test results[J].Magazine of Concrete Research,1986,38(137):206-219.
[23]Ramakrishnan V,Ananthanarayana Y.Ultimate strength of deep beams in shear[C]//ACI Journal Proceedings,1968,65(2):87-98.
[24]刘立新,谢丽丽,陈萌.钢筋混凝土深受弯构件受剪性能的研究[J].建筑结构,2000,30(10):19-22.Liu Lixin,Xie Lili,Chen Meng.The shear strength capability of reinforced concrete deep flexural members[J].Building Structure,2000,30(10):19-22.(in Chinese)
[25]龚绍熙.钢筋混凝土深梁在对称集中荷载下抗剪强度的研究[J].郑州工学院学报,1982,1:52-68.Gong Shaoxi.The shear strength capability of reinforced concrete deep beam under symmetric concentrated loads[J].Journal of Zhengzhou Technology Institute,1982,1:52-68.(in Chinese)
[26]Walravena J,Lehwalter N.Size effects in short beams loaded in shear[J].ACI Structural Journal,1994,91(5):585-593.