钢-玄武岩纤维复合筋混凝土框架结构非线性地震反应分析
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摘要
钢-纤维复合筋是一种耐腐蚀、具有稳定二次刚度等特性的新型结构材料。开展了钢-玄武岩纤维复合筋混凝土框架结构的非线性地震反应研究工作,由复合筋的应力-应变本构关系出发,利用修正Gauss-Radau积分法推导了杆件单元柔度矩阵,并用于框架结构非线性时程响应分析。参考现行规范设计了一个8度区的普通钢筋混凝土多层框架结构和一个对比钢-玄武岩纤维复合筋混凝土框架结构,比较了两个结构在相同地震输入下结构自振周期变化率、非线性时程响应和杆端出铰时间和位置等抗震性能指标。结果表明:在多遇和罕遇地震动输入下,配置钢-玄武岩纤维复合筋混凝土框架结构的最大弹塑性位移与层间转角等指标比普通钢筋的框架结构有所减小;在罕遇水准的地面运动输入下结构自振周期变化率小于RC框架结构,结构刚度退化和损伤程度更小;杆端出铰时间相对更晚、数量更少且更易形成梁铰塑性耗能机制。钢-玄武岩纤维复合筋可充分利用材料的强度,通过合理配置钢筋与玄武岩纤维的比例能够有效控制框架结构的塑性变形、减小结构残余位移,从而减小重力二阶效应对柱的不利影响,改善结构在大震下的性能,确保大震不倒的安全性能目标。
Steel-fiber-reinforced polymer composite bar( SFCB) is a new kind of reinforcing material. It has some excellent properties,such as,corrosion-resistance and stable post-yield stiffness. Here,the nonlinear seismic response analysis of a steel-basalt fiber composite bars concrete frame was performed including deducing the flexibility matrix of the bar element based on Gauss-Radau integral method and using this matrix for nonlinear time history response analysis of the frame structure. A RC frame and a corresponding SFCB concrete frame were designed in na area subjected to 8 earthquake according to the current code for design of concrete structures. Their aseismic performance indexes,including rates of natural vibration period,nonlinear time history response,and when and where the plastic hinge emerged were compared.The results showed that the SFCB frame has smaller interlayer displacement angle and maximum elasto-plastic displacement than the RC frame does under the frequent and rare earthquake ground motions; under the rare earthquake ground motion,the SFCB frame has a smaller rate of natural vibration period than the RC frame does,with even slighter stiffness degradation and damage level; furthermore,fewer plastic hinges appear at the ends of the members in the SFCB frame at a relatively later time,it is easier to form the beam-hinge plastic energy dissipation mechanism; the steel-basalt fiber composite bars can make full use of the strength of materials by appropriately deploying steel bar and basalt fiber to effectively control the plastic deformation of the frame and decrease the residual displacement of the frame structure,and thus to reduce the gravity second-order effect on columns and improve the aseismic performance of the whole structure.
Steel-fiber-reinforced polymer composite bar( SFCB) is a new kind of reinforcing material. It has some excellent properties,such as,corrosion-resistance and stable post-yield stiffness. Here,the nonlinear seismic response analysis of a steel-basalt fiber composite bars concrete frame was performed including deducing the flexibility matrix of the bar element based on Gauss-Radau integral method and using this matrix for nonlinear time history response analysis of the frame structure. A RC frame and a corresponding SFCB concrete frame were designed in na area subjected to 8 earthquake according to the current code for design of concrete structures. Their aseismic performance indexes,including rates of natural vibration period,nonlinear time history response,and when and where the plastic hinge emerged were compared.The results showed that the SFCB frame has smaller interlayer displacement angle and maximum elasto-plastic displacement than the RC frame does under the frequent and rare earthquake ground motions; under the rare earthquake ground motion,the SFCB frame has a smaller rate of natural vibration period than the RC frame does,with even slighter stiffness degradation and damage level; furthermore,fewer plastic hinges appear at the ends of the members in the SFCB frame at a relatively later time,it is easier to form the beam-hinge plastic energy dissipation mechanism; the steel-basalt fiber composite bars can make full use of the strength of materials by appropriately deploying steel bar and basalt fiber to effectively control the plastic deformation of the frame and decrease the residual displacement of the frame structure,and thus to reduce the gravity second-order effect on columns and improve the aseismic performance of the whole structure.
引文
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[10]高芳清,金建明,高淑英.基于模态分析的结构损伤检测方法研究[J].西南交通大学学报,1998,33(1):108-113.GAO Fang-qing,JIN Jian-ming,GAO Shu-ying,Damage detection in structures by modal analysis[J].Journal of Southwest Jiaotong University,1998,33(1):108-113.
[2]罗云标.钢-连续纤维复合筋及其增强混凝土结构性能研究[D].南京:东南大学,2008.
[3]Sun Z Y,Wu G,Wu Z S,et al.Seismic behavior of concrete columns reinforced by steel-FRP(fiber-reinforced polymer)composite bar[J].J Compos Constr,2011,15(5):696-706.
[4]汪训流,叶列平,陆新征.往复荷载下预应力混凝土结构的数值模拟[J].工程抗震与加固改造,2006,28(6):25-29.WANG Xun-liu,YE Lie-ping,LU Xin-zheng,Numerical simulation for the hysteresis behavior of pre-stressed concrete structures under cyclic loads[J].Earthquake Resistant Engineering and Retrofitting,2006,28(6):25-29.
[5]Menegotto M,Pinto P E.Method of analysis of cyclically loaded RC plane frames including changes in geometry and non-elastic behavior of elements under normal force and bending[R].Lisbon,Portugal:Preliminary Report,IABSE,1973,13:15-22.
[6]Kent D C,Park R.Fl exural members with confined-concrete[J].Journal of the Structural Division,1971,97:1969-1990.
[7]Scott Michael H,Fenves Gregory L.Plastic hinge integration methods for force-based beam-column elements[J].Journal of Structural Engineering,2006,132(2):244-252.
[8]刘如驰.用于抗震能量分析的混凝土框架杆系模型[D].南京:东南大学,2012.
[9]陈滔,黄宗明.基于有限单元柔度法的钢筋混凝土空间框架非弹性地震反应分析[J].建筑结构学报,2004,25(2):79-84.CHEN Tao,HUANG Zong-ming,Flexibility based finite element method for inelastic seismic response analysis of reinforced concrete space frames[J].Journal of Building Structures,2004,25(2):79-84.
[10]高芳清,金建明,高淑英.基于模态分析的结构损伤检测方法研究[J].西南交通大学学报,1998,33(1):108-113.GAO Fang-qing,JIN Jian-ming,GAO Shu-ying,Damage detection in structures by modal analysis[J].Journal of Southwest Jiaotong University,1998,33(1):108-113.
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