混凝土重力坝抗震配筋加固措施的效果研究
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摘要
混凝土坝遭遇强烈地震导致坝体严重受损已有先例。工程界建议布置坝面钢筋以提高坝体抗震性能。基于此,本文应用嵌入式滑移模型和钢筋刚化模型模拟混凝土重力坝配筋前后的地震动力响应,据此评价坝面配筋措施的抗震效果。计算结果显示,配筋前后结构整体响应基本一致,但布置坝面钢筋后坝体裂缝由集中裂缝分散为多条裂缝,裂缝张开位移和扩展深度较配筋前减小;此外,钢筋滑移对坝体裂缝分布形态也有一定影响。研究表明:配置坝面钢筋对限制与分散混凝土开裂将起到一定的作用,有助于提高混凝土坝抗震性能。
Several concrete dams have suffered severe damage under strong earthquake.The reinforcement concept has been advanced to improve the seismic-resistant capacity of dams.The dynamic response of a concrete dam before and after strengthening has been simulated by the embedded slip model and the reinforcement stiffening model respectively.The global response results after reinforcement are almost consistent with those before reinforcement.However,the cracking behavior of concrete is significantly affected by reinforcement interactions,especially accounting for bond-slip effects.A major crack formed before strengthening is becomed into several cracks after strengthening and the maximum CODs(ckack opening displacements) significantly decrease at the same time. The results show that the reinforcement is a useful measure to improve the earthquake-resistant capacity of concrete dams.
Several concrete dams have suffered severe damage under strong earthquake.The reinforcement concept has been advanced to improve the seismic-resistant capacity of dams.The dynamic response of a concrete dam before and after strengthening has been simulated by the embedded slip model and the reinforcement stiffening model respectively.The global response results after reinforcement are almost consistent with those before reinforcement.However,the cracking behavior of concrete is significantly affected by reinforcement interactions,especially accounting for bond-slip effects.A major crack formed before strengthening is becomed into several cracks after strengthening and the maximum CODs(ckack opening displacements) significantly decrease at the same time. The results show that the reinforcement is a useful measure to improve the earthquake-resistant capacity of concrete dams.
引文
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[2]Zhang C,Xu Y,Wang G,et al.Non-linear seismic response of arch dams with contraction joint opening and joint reinforcements[J].Earthquake Engineering and Structural Dynamics,2000,29(10):1547~1566.
[3]郭永刚,涂劲,陈厚群.抗震钢筋对高拱坝抗震性能的影响[J].水利学报,2004:1~6.
[4]刘新佳.拱坝地震响应非线性分析与抗震措施的数值模型研究[D].北京:清华大学博士论文,2003.
[5]侯顺载,胡晓,涂劲.底缝对高拱坝地震反应影响的研究[J].云南水力发电,2000,16(1):50~54.
[6]Lee J,Fenves G L.Plastic-damage concrete model for earthquake analysis of dams[J].Earthquake Engineering and Structural Dynamics,1998,27(9):937~956.
[7]杜容强,林皋,胡志强.混凝土重力坝动力弹塑性损伤安全评价[J].水利学报,2006,37(9):1056~1062.
[8]龙渝川,周元德,张楚汉.模拟钢筋-混凝土相互作用效应的钢筋刚化方法[J].清华大学学报自然科学版,2007,47(6):793~796.
[9]龙渝川,张楚汉,周元德.钢筋混凝土嵌入式滑移模型[J].工程力学,2007,24(增刊1):41~45.
[10]Bazant Z P,Oh B H.Crack band theory for fracture of concrete[J].Materiaux et Constructions(Materials and Structures),1983,16(93):155~177
[11]National Concrete Masonry Association.Cracking of concrete members in direct tension[R].Report No.ACI224.2R-92,Farmington Hills,Michigan:American Concrete Institute,1992,1~12.
[12]Lowes L N,Moehle J P,Govindjee S.Concrete-steel bond model for user in finite element modeling of reinforced concrete structures[J].ACI Structural Journal,2004,101(4):501~511.
[13]Eligehause R,Popov E P,Bertero V V.Local bond stress-slip relationships of deformed bars under generalized excitations[R].Report No.UCB/EERC-83/23,EERC,University of California,Berkeley,1983.
[14]龙渝川,张楚汉,周元德.基于弥散与分离裂缝模型的混凝土开裂比较研究[J].工程力学,2008,25(3):80~84.
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