钢筋混凝土及预应力混凝土梁抗剪设计方法研究
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孟少平1，王国林2，潘钻峰3（1 东南大学土木工程学院， 南京 210096； 2 上海应用技术学院城市建设与安全工程学院，上海 201418； 3 同济大学土木工程学院， 上海 200092）［摘要］ 对几个典型的基于截面的抗剪设计方法和基于拉压杆模型的抗剪设计方法进行了讨论，并建立剪切试验数据库对其进行了评估比较。显式修正压力场理论（MCFT）方法和加拿大规范CSA-04规范公式分别对钢筋混凝土（RC）梁（剪跨比λ≥ 2.4）和预应力混凝土（PC）梁（λ≥2.0）的预测精度最高，而对于小剪跨比RC梁（λ≤2.0）和PC梁（λ≤ 2.5），改进的拉压杆模型（MSTM）和我国《混凝土结构设计规范》（GB 50010—2010）公式的预测结果均偏于安全，但MSTM因合理考虑了预应力贡献，精度较高。基于数据库研究表明，轴向预压应力对梁抗剪的有利作用存在一个上限，而试验研究表明曲线预应力筋竖向分力的抗剪作用同时与剪跨比和纵筋配筋率相关。［关键词］钢筋混凝土; 预应力混凝土; 基于截面的抗剪设计方法; 拉压杆模型; 预应力效应中图分类号：TU375.1， TU378.1 文献标识码：A 文章编号：1002-848X(2013)19-0025-05Study on shear design methods for reinforced and prestressed concrete beamsMeng Shaoping1, Wang Guolin2, Pan Zuanfeng3(1 School of Civil Engineering, Southeast University, Nanjing 210096, China; 2 College of Urban Construction and Safety Engineering, Shanghai Institute of Technology, Shanghai 201418, China; 3 College of Civil Engineering, Tongji University, Shanghai 200092, China)Abstract: Several sectional design methods and the strut and tie methods for shear had been discussed. Shear database was established respectively to evaluate the design methods. Among the sectional design methods, the explicit Modified Compression Field Theory(MCFT) method gives a good agreement with test results of RC beams with shear span-to-effective depth ratio, λ larger than 2.4, and so does the CSA-04 design formula for PC beams with λ larger than 2.0. For RC beams (λ≤2.0) and PC beams (λ≤2.5), both modified strut and tie model (MSTM) and Chinese code for design of concrete structures(GB 50010—2010) give safe predictions, and MSTM is more accurate due to its reasonable consideration of the prestress effect. Besides, the favorable effect of the axial prestressing on shear strength is verified to have an upper limit through shear database, and the contribution of vertical component of draped tendons is related to both λ and longitudinal reinforcement ratio.Keywords: reinforced concrete; prestressed concrete; sectional design method for shear; strut and tie model; prestress effect作者简介：孟少平，博士，教授，博导，Email: cardoso_meng@sina.com。参考文献［1］ASCE-ACI Committee 445. Recent approaches on shear design of structural concrete［J］. ASCE Journal of Structural Engineering, 1998, 124(12): 1375-417.［2］AASHTO LRFD Bridge specifications SI Units Third Edition［S］. USA: American Association of State Highway and Transportation Officials, 2004.［3］ACI 318R-08. Building code requirements for structural concrete and commentary［S］. Farmington(MI): American Concrete Institute, 2008.［4］CSA Committee A23.3. Design of concrete structures (CSA A23.3-04)［S］. Mississauga: Canadian Standards Association, 2004.［5］GB 50010—2010 混凝土结构设计规范［S］. 北京: 中国建筑工业出版社, 2010.［6］GB 50010—2002 混凝土结构设计规范［S］. 北京: 中国建筑工业出版社, 2002.［7］COLLINS M P. Towards a rational theory for RC members in shear［J］. Journal of the Structural Division, ASCE, 1978, 104(4): 649-666.［8］VECCHIO F J, COLLINS M P. The modified compression field theory for reinforced concrete elements subjected to shear［J］. ACI Journal Proceedings, 1986, 83(2): 219-231.［9］BENTZ E C, COLLINS M P. Development of the 2004 CSA A23.3 shear provisions for RC［J］. Canadian Journal of Civil Engineering, 2006, 33(5): 521-534.［10］潘钻峰. 混凝土结构时效变形及受剪性能试验与理论研究［D］. 南京: 东南大学, 2011.［11］王国林. 预应力混凝土梁受剪性能试验研究与理论分析［D］. 南京: 东南大学, 2009.［12］KUPFER H B, GERSTLE K H. Behavior of concrete under biaxial stress［J］. ASCE Journal of Engineering Mechanics Division, 1973, 99(EM4): 853-866.［13］王国林, 孟少平, 黄仕平. 一种预测深受弯构件受剪承载力的协调方法［J］.建筑结构,2009,39(4):97-99.［14］SHAHAWY M A, BATCHELOR B. Shear behavior of full-scale PC girders: Comparison between AASHTO Specification and LRFD Code［J］. PCI Journal, 1996, 41(3): 48-62.
