摘要
纤维增强复合材料(Fiber Reinforced Polymer,简称FRP)以其轻质、高强、抗疲劳等优越的力学性能,广泛地应用于工程结构加固领域之中。表层嵌贴加固法是FRP材料加固钢筋混凝土结构的一种新的应用形式,较外贴加固法在某些方面具有明显优势,具有远大的发展前景。
本文结合已有试验数据,采用大型通用有限元软件ANSYS 10.0建立了表层嵌贴CFRP板条抗弯加固钢筋混凝土梁的三维非线性有限元模型,数值模拟了加载的全过程。然后将该模型用于加固梁抗弯性能的参数影响分析,主要考察了承载力、刚度、延性和破坏模式等方面。最后对表层嵌贴FRP抗弯加固梁中不同材料的应力分布规律进行了初步的探讨,获得了试验中相对不易观察到的数据。
研究结果表明:加固后,梁的极限承载力和开裂后刚度得到了较大的提高;CFRP板条的嵌贴长度、宽度、厚度、弹性模量、抗拉强度和胶层的弹性模量对加固梁的抗弯性能有较大影响;在板端附近,FRP的正应力沿板宽方向的分布发生了奇异,与纯弯段有较大区别;对于不同嵌贴长度的加固梁,胶层中的最大剪出现的位置是不相同的。
Fiber Reinforced Polymer(FRP) has been widely used in the field of strengthening structures due to its advantages such as high strength-to-weight ratio and good fatigue properties. Near-surface Mounted(NSM) reinforcement is emerging as a latest strengthening techniques for reinforced concrete structures and is showing great prospect, as it offers some real advantages over externally bonded(EB) FRP reinforcement.
Based on existing test data, this paper presents analysis of CFRP strips NSM flexurally strengthened RC beams using 3-D nonlinear element model which is implemented in ANSYS 10.0 and numerically simulate the whole process of load application. And then an extensive parameter influence analysis is given mainly focused on capacity, rigidity, ductility and failing modes. At last, different stress distributions of NSM strengthened RC beams are tentatively explored, and someresults not easily observed in tests are obtained.
Following conclusions can be drawn: the NSM reinforcement improves the ultimate capacity and post-cracking rigidity; embedment length, width, thickness, elastic modulus, tension strength of CFRP and elastic modulus of groove filler have great influence on the flexural behavior of strengthened RC beams; normal stress distribution of FRP near the plate end is different from other region; the maximum shear stress of groove filler is on different location as the embedment length different.
引文
[1]姚谏.FRP复合材料加固混凝土结构新技术研究进展[J].科技通报,2004,20(3):216-22
[2]飞云江大桥检查报告[R].杭州:浙江省交通规划设计研究院,2007
[3]中华人民共和国国家标准.混凝土结构加固设计规范(GB50367-2006)[S],中国建筑工业出版社,2006
[4]De Lorenzis L,Teng JG.Near-surface mounted FRP reinforcement:An Emerging Technique for Strengthening Structures[J],Composites:Part B 38(2007):119-143
[5]中国工程建设标准化协会标准.碳纤维片材修复加固混凝土结构技术规程(CECS146:2003)[S].北京:中国计划出版社,2003
[6]Asplund SO.Strengthening Bridge Slabs with Grouted Reinforcement[J],Journal of the American Concrete Institute,1949,20(6):397-406
[7]De Lorenzis L,Rizzo A,La Tegola A.A Modified Pull-out Test for Bond of Near-Surface Mounted FRP Rods in Concrete[J],Composites Part B:Engineering,2002,33(8):589--603
[8]De Lorenzis L.Strengthening of RC structures with near surface mounted FRP rods[D],PhD Thesis,Department of Innovation Engineering,University of Lecce:Italy,2002.
[9]Parretti R,Nanni A.Strengthening of RC members using near-surface mounted FRP composites:design overview[J],Advances in Structure Engineering,2004,7(6):469-483
[10]陆新征,谭壮,叶列平,江见鲸.FRP布一混凝土界面粘结性能的有限元分析[J],工程力学,2004,21(6):45-50
[11]陆新征,叶列平,滕锦光,庄江波.江见鲸.FRP片材与混凝土粘结性能的精细有限元分析[J],工程力学,2006,23(5):74-82
[12]叶锋.FRP-混凝土粘结性能的有限元分析[D].杭州:浙江大学,2007
[13]Yang ZJ,Chen JF,Proverbs D.Finite element modeling of concrete cover separation failure in FRP plated RC beams[J],Construction and Building Materials,2003(17):3-13
[14]Guido Camata,Enrico Spacone,Roko Zarnic.Experimental and nonlinear finite element studies of RC beams strengthened with FRP plates[J],Composites:Part B,2007(38):277-288
[15]Damian K,Thomas M,Sofomon Y.Finite Element Modeling of Reinforced Concrete Structures Strengthened with FPR laminates[R],Report for Oregon Department of transportation,Salem,May,2001
[16]陆新征,滕锦光,叶列平,江见鲸.FRP加固混凝土梁受弯剥离破坏的有限元分析[J],工程力学,2006,23(6):85-93
[17]杨洋,李丽娟,郭永昌,黄彦培.CFRP/GFRP混杂加固混凝土梁胶层界面应力有限元分析[J],混凝土,2007,8:13-17
[18]Santhakumar R,Chandrasekazan E,Dhanaraj R.Analysis of Retrofitted Reinforced Concrete Shear Beams using Carbon Fiber Composites[J],Electronic Journal of Structure Engineering,2004(4):66-74
[19]张子潇,叶列平,陆新征.U型FRP加固钢筋混凝土梁受剪剥离性能的有限元分析[J],工程力学,2005,22(4):155-163
[20]Hassan T,Rizkalla S.Investigation of bond in concrete structures strengthened with near surface mounted carbon fiber reinforced polymer strips[J],Journal of Composites f or Construction,2003,7(3):248-257
[21]Hassan T,Rizkalla S.Bond mechanism of near-surface-mounted fiber-reinforced polymer bars for flexural strengthening of concrete structures[J],Journal of Composites for Construction,2004,101(6):830-839
[22]De Lorenzis L,Nanni A,La Tegola A.Flexural and shear strengthening of reinforced concrete structures with near surface mounted FRP rods[C],In:Proceedings ACMBS Ⅲ,Ottawa(Canada),2000:521-528
[23]El-Hacha R,Rizkalla S.Near-surface-mounted fiber-reinforced polymer reinforcements for flexural strengthening of concrete structures[J],ACI Structure Journal,2004,101(5):717-726
[24]Alkhrdaji T,Nanni A,Chen G,Barker M.Upgrading the transportation infrastructure: solid RC decks strengthened with FRP[J], Concrete International, 1999, 21(10): 37-41
[25] Hassan T, Rizkalla S. Flexural Strengthening of Prestressed Bridge Slabs with FRP Systems[J], PCI Journal, 2002, 47: 76-93
[26]Teng JG, De Lorenzis L, Wang B, Rong L, Wong TN, Lam L. Debonding failures of RC beams strengthened with near-surface mounted CFRP strips[J], Journal of Composites for Construction, 2006, 10(2) : 92-105
[27]Taljsten B, Carolin A, Nordin H. Concrete structures strengthened with near surface mounted reinforcement of CFRP[J], Advances in Structure Engineering, 2003, 6(3): 201-213
[28]Barros JAO, Ferreira DRSM. Fortes AS and Dias SJE. Assessing the Effectiveness of Embedding CFRP Laminates in the Near Surface for Structural Strengthening[J], Construction and Building Materials, 2006, 20(7): 478-491
[29]Barros JAO , Varma RK, Sena-Cruz JM, Azevedo AFM. Near surface mounted CFRP strips for the flexural strengthening of RC columns[J], Engineering Structures, 2008, 30: 3412-3425
[30]Tang WC, Balendran RV, Nadeem A, Leung HY. Flexural Strengthening of Reinforced Lightweight Polystyrene Aggregate Concrete Beams with Near-surface Mounted GFRP Bars[J], Building and Environment, 2006,41(10): 1381-1393
[31]Moataz Badawi, Khaled Soudki. Flexural Strengthening of RC beams with prestressed NSM CFRP rods-Experimental and analytical investigation [J], Construction and Building Materials, 2009, 23: 3292-3300
[32]Firas A, Arnaud C, Raoul F, Christian T. RC beams strengthened with NSM CFRP rods and modeling of peeling-off failure[J], Composites Structures, 2010
[33] Roberto Capozucca. Static and dynamic response of damaged RC beams strengthened with NSM CFRP rods[J], Composites Structures, 2009. 91: 237-248
[34]A1-Mahmoud F, Castel A, Francois R, Christian T. Strengthening of RC members with near-surface mounted CFRP rods-Experimental and analytical investigation[J],Composites Structures,2009,91:138-147
[35]王韬.钢筋混凝土梁表层嵌贴CFRP的抗弯加固性能研究[D],杭州:浙江大学,2005
[36]袁霓绯.表层嵌贴CFRP板加固钢筋混凝土梁的抗弯承载力研究[D],杭州:浙江大学,2006
[37]贺学军,周朝阳,徐玲.内嵌CFRP板条加固混凝土梁的抗弯性能试验研究[J],土木工程学报,2007,41(12):14-20
[38]王天稳,常勇.CFRP布NSM加固砼梁的抗弯性能试验研究[J],武汉理工大学学报,2009,31(2):111-115
[39]曾宪桃,成香莉,高保彬.内嵌碳纤维增强塑料板条抗弯加固混凝土梁试验研究[J],工程力学,2008,25(12):106-114
[40]梁金福,燕柳斌,赵君君.碳纤维板条嵌入式加固钢筋混凝土梁试验研究[J],混凝土,2009,1:46-49
[41]吴刚,罗云标,吴智深,张敏,胡显奇.钢一连续纤维复合筋(SFCB)嵌入式加固混凝土梁试验研究[J],工程抗震与加固改造,2009:31(1),8-14
[42]宾羽飞.表层嵌贴CFRP加固混凝土梁抗弯性能试验研究[D],南京:南京理工大学,2007
[43]Deric John Oehlers,Irene Liu,Rudolf Seracino.A generic design approach for EB and NSM longitudinally plated RC beams[J],Construction and Building Materials,2007,21:697-708
[44]周朝阳,李毅卉,贺学军.T形截面钢筋混凝土梁内嵌FRP加固后抗弯承载力计算[J],铁道科学与工程学报,2005,2(4):50-53
[45]周延阳.混凝土表层嵌贴CFRP粘结机理研究[D].杭州:浙江大学,2005
[46]廖志刚.FRP复合材料与混凝土的粘结性能有限元分析[D],杭州:浙江大学,2008
[47]汪光满.钢筋混凝土梁表层嵌贴CFRP板条的抗弯加固性能有限元分析[D].杭州:浙江大学,2008
[48]Gilles Foret,Oualid Limam.Experimental and numerical analysis of RC two-way slabs strengthened with NSM CFRP rods[J],Construction and Building Materials,2008,22:2025-2030
[49]岳清瑞,李庆伟,杨勇新.纤维增强复合材料嵌入式加固技术[J],工业建筑,2004,34(1):1-4
[50]贾庆扉.混凝土梁表层嵌贴CFRP板条的抗剪加固试验研究[D],杭州:浙江大学,2006
[51]郝文化主编.ANSYS土木工程应用实例[M],北京:中国水利水电出版社,2005
[52]李为民等.ANSYS工程结构实用案例分析[M],北京:化学工业出版社,2007
[53]中华人民共和国国家标准.混凝土结构设计规范(GB50010-2002)[S],北京:中国建筑工业出版社,2002
[54]吕西林,金国芳,吴晓涵编著.钢筋混凝土结构非线性有限元理论与应用[M],同济大学出版社,1997
[55]陆新征,江见鲸.用ANSYS Solid65单元分析混凝土组合构件复杂应力[J].建筑结构,2003,33(6):22-24
[56]江见鲸著.钢筋混凝土结构非线性有限元分析[M].西安:陕西科学技术出版社
[57]互动空间.ANSYS中混凝土结构的计算问题[J],工业建筑,2007:37(11),116-119
[58]陆新征.Ansys&Solid65单元分析钢筋混凝土[清华大学课程讲义],北京:清华大学,2004
