【摘要】 以栗子坪大桥为实例,研究大跨径曲线高墩预应力混凝土连续刚构桥的自振特性。应用Midas有限元软件分别建立直线桥、曲率半径分别为1 500 m、2 000 m和2 500 m的曲线高墩预应力混凝土连续刚构桥的有限元计算模型,计算得到该桥梁结构的自振频率和振型。分析计算结果可以得出结论:曲线桥与直线桥的振型特征大致一样,随着曲率半径的减小,桥梁前几阶振型中各个方向振型的耦合程度变大;大跨径曲线高墩预应力混凝土连续刚构桥的第1阶振型为桥墩纵向振动,桥墩纵向弯曲刚度更弱;桥梁第2阶振型为主梁横向弯曲振动,且前15阶振型中有6阶是主梁和桥墩的横向振动,主梁横向抗弯刚度相对于竖向刚度较小;随着曲率半径的减小,基频逐渐减小,曲率半径较大(如1 500 m以上)时,曲率半径的变化对大曲率半径连续刚构桥周期的影响较小。计算结果对认识大跨径曲线高墩连续刚构桥的振动特点有较大参考价值。更多还原

【Abstract】 Taking Liziping grand bridge which is highway control engineering from Luoyang to Songxian for an actual example,free vibration characteristics of long-span curved rigid frame bridges with high piers are studied,using to numerical analytic method.Applying bridge software to build straight bridge and radius of curvature 1 500 m,2 000 m,2 500 m long-span curved rigid frame bridges finite element model,free vibration frequency,period and modal shape are obtained.Through analysis,some conclusion are obtained that the first modal shape is longitudinal vibration of piers and transverse vibration appears at the second modal shape.The main girder’s vertical stiffness is the most relative big.Basic frequency reduces along with decrease of curvature radius.But curved bridge’s modal shape is same as straight bridge’s.As curvature radius is more big(greater than 1500m),the effect of curvature radius to free vibration is more less.更多还原