学术论文列表
高强箍筋约束高强混凝土柱抗震性能研究综述
摘要：强烈地震作用下,高强箍筋对保证高强混凝土柱的抗震能力具有重要意义。为研究高强箍筋约束高强混凝土柱的抗震性能,对国内外进行的混凝土抗压强度在40~112MPa、箍筋屈服强度在400~1569MPa的混凝土柱的抗震拟静力试验结果进行广泛总结,发现基于普通强度混凝土得出的钢筋混凝土柱压弯构件的矩形应力图、抗剪承载力及塑性铰区约束箍筋用量计算公式并不适用于高强箍筋约束的高强混凝土柱,对此应进行修正。对高强混凝土柱的延性抗震能力,一个基本结论为,对于承受较高轴压的高强混凝土柱,通过合理配置高强箍筋,是可以充分保证其延性和耗能能力的;而对于承受较低轴压的高强混凝土柱,只要箍筋间距满足要求,使用高强箍筋一般能保证其延性抗震性能。
液化场地桥梁桩基础震害及其抗震研究概述
摘要：砂土液化是桥梁结构严重破坏甚至倒塌的重要影响因素。该文总结了几次大地震中液化场地桥梁桩基础震害情况,简要评述了这一领域的研究现状。通过对比国内外桥梁抗震设计规范,认为我国规范基础抗震设计部分明显不足。结合国内地震液化灾害分布特点和桥梁建设实际情况,强调了深入开展液化场地桥梁桩基础抗震性能研究的必要性和紧迫性。
基于位移设计的钢筋混凝土桥墩抗震性能试验研究(Ⅰ):拟静力试验
摘要：通过拟静力试验研究了基于位移设计钢筋混凝土桥墩的抗震性能。利用基于位移抗震设计方法和桥梁抗震规范方法设计了各2根和1根1:2.5比例钢筋混凝土桥墩试件,对低周反复荷载作用下试件试验破坏形态、承载力、位移延性、滞回耗能、刚度退化等方面进行了比较分析,可以认为基于位移设计的钢筋混凝土桥墩能够达到预期的延性抗震要求,并且在相对耗能能力(与理想弹塑性模型相比)、刚度退化性能方面与现行规范抗震设计方法设计的桥墩相当。试验表明建议的钢筋混凝土桥墩基于位移的抗震设计方法是实际可行的。
Experimental research and finite element analysis of bridge piers failed in flexure-shear modes
摘要：In recent earthquakes,a large number of reinforced concrete (RC) bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers.An integrated experimental and finite element (FE) analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes.In the first part,a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally.The damage states,ductility and energy dissipation parameters,stiffness degradation and shear strength of the piers are studied and compared with each other.The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure.The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking,and in some cases,rupturing of spiral bars.In the second part,modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software.A set of models with different parameters is selected and evaluated through comparison with experimental results.The influences of the shear retention coefficients between concrete cracks,the Bauschinger effect in longitudinal reinforcement,the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretic curves are discussed.Then,a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones.This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.
单调加载方式下桥墩的有限元建模方法研究
摘要：基于钢筋混凝土桥墩低周反复荷载试验结果,利用ANSYS软件,建立了单调加载方式下桥墩的有限元计算模型,讨论了不同的混凝土本构关系和有限元求解方法对计算结果的影响,并将模拟得到的桥墩屈服荷载、极限荷载以及荷载-位移曲线与试验结果进行了对比。结果发现,采用约束混凝土的本构关系可得到更好的收敛效果,但弧长法求解对收敛性影响不大;所建立的有限元模型可以较好的模拟桥墩的屈服荷载和极限荷载。
钢筋混凝土桥墩地震破坏振动台试验研究
摘要：钢筋混凝土桥墩箍筋约束不足和剪跨比过小(短柱)造成的脆性剪切破坏在近几次地震桥梁震害中占有较大比重.为解决此问题设计制作了各3根圆形截面和方形截面桥墩试件,分别代表具有良好箍筋约束、配箍率不足和小剪跨比3种情况,并通过振动台试验研究了其抗震性能.对小震、中震和大震作用下桥墩试件的破坏形态、加速度和位移反应、位移延性系数和耗能等方面进行了比较分析,结果表明,小剪跨比桥墩在地震作用下反应位移延性系数较大,在抗震设计时应引起足够重视.
复杂三维框支-剪力墙结构动力特性与地震反应谱分析
摘要：为避免抗震设计规范中定性条文的不确定性限制而影响对复杂型式高层结构整体抗震性能的合理评价,建立大规模三维有限元数值模型,针对典型工程结构采用Lanczos法提取考虑阻尼和静力初始状态影响的结构自然频率与振型,并在此基础上进行双向水平地震力下考虑扭转效应的振型分解反应谱分析.计算结果表明:扭转振型的阶次较低,扭转周期与平动周期接近,扭转周期比满足规范限值要求;结构两个主轴方向的侧移刚度差异显著,结构沿高度存在多处刚度转换层,层间位移角发生多处突变;线性层间位移角幅值满足规范限值要求,但结构局部层间位移转角过大,在设计中应予以考虑.
Displacement based seismic design of RC bridge piers:Method and experimental evaluation
摘要：A direct displacement based seismic design procedure of RC bridge piers fulfilled multiple performance objectives, which usually expressed as that designed structures can resist against minor earthquake without any damage, resist against moderate earthquake with repairable structural damage and resist against strong earthquake without collapse, is developed based on the improved capacity spectrum method. The procedure uses the yield displacement and displacement ductility factor as design parameters, uses inelastic seismic demand spectrum with yield spectral accelerations and yield displacements format to calculate seismic demands of the pier under different earthquake design levels. Seismic capacities of the pier are determined by acceptable structural damage states, which are estimated quantitatively by both of the strains of concrete and longitudinal steels in plastic hinge zone and expressed as displacements at top of the pier by transforming from relationship between curvature ductility factor and displacement ductility factor. Two specimens with 1:2.5scale are designed by the proposed method and another reference specimen with same scale is designed according to bridge seismic design code in China. The damage states, bearing capacities, ductility, and energy dissipation of specimens are compared when they are subjected to cyclic loading. Then four bridge specimens with 1:2 scale to the specimens in the completed cyclic test, 3 based on displacement-based seismic design method and 1 based on bridge seismic design code in China, are tested on shaking table. Results of cyclic test and shaking table test show that ductility capacities of bridge piers designed using displacement-based method are fulfilled seismic demands expected. The proposed displacement based seismic design method can be applied to the bridge design in the earthquake regions.
EVALUATION OF THE SEISMIC PERFORMANCE OF REINFORCED CONCRETE BRIDGE COLUMNS BASED ON PLASTIC HINGE MODEL
摘要：Plastic hinge model has been widely used in bridge seismic design codes such as Japan, Caltrans, New Zealand and China (revised edition), to evaluate deformation capacity of RC bridge columns. With the development of bridge performance/displacement based seismic design, several damage indices have been suggested, such as ultimate curvature and curvature ductility factor of critical section, maximum strain of confined concrete and reinforced steels, low cycle fatigue damage indices of longitudinal reinforcement etc. To study the accuracy degree of damage indices calculated with plastic hinge models and the main influencing factor, a computer program was developed employing 5 plastic hinge models to compute aforesaid damage indices compared with test data of RC bridge columns. The study results show that force-displacement curves and residual deformation calculated match the experiment with adequate accuracy, but the strain of longitudinal steel is overestimated and the strain of core concrete is underestimated. The computed ultimate curvature is lower than experiment results when shear span ratio is not less than 8. It is also recognized that under the same loading control displacement, loading path hardly affects the aforesaid damage indices.
不规则钢筋混凝土梁桥抗震性能评价N2方法
摘要：将非线性静力分析(Pushover)和非线性时程分析结合起来,给出了一个用于不规则钢筋混凝土梁桥抗震性能评价的N2方法(名称源于Fajfar).首先对多个代表性桥墩进行非线性静力分析,获得桥墩的"能力"曲线以及不同破损极限状态对应的墩顶位移.不同破损极限状态由钢筋和混凝土的应变以及桥墩截面抗剪能力共同定义,并可由墩底截面弯矩——曲率关系曲线转化为以墩顶位移的表述形式.再通过全桥模型的非线性时程分析获得各个桥墩的地震"需求"位移,最后通过二者比较来评价桥梁的抗震性能.给出了一个曲线连续梁桥计算实例,验证了方法的可行性.
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