时速400km高速铁路预应力混凝土简支梁竖向基频下限探讨

以24～40 m典型跨度简支梁为研究对象,通过有限元计算分析,确定不同跨度桥梁及不同列车荷载的简支梁容许动力系数.基于移动荷载列-桥梁动力仿真模型,探究列车移动荷载列形式、列车时速、简支梁跨度、竖向基频对梁体动力响应的影响规律.结合梁体振动加速度、容许动力系数和规范要求,确定时速400 km高速铁路预应力混凝土简支梁桥...

Discussion on Lower Limit of Vertical Fundamental Frequency of Prestressed Concrete Simply-supported Girder of 400 km/h High Speed Railway

Taking the simple-supported girder with typical span of 24~40 m as the research object,the allowable dynamic coefficients of simple-supported girder with different span bridges and different train loads were determined through finite element calculation and analysis.Based on the dynamic simulation model of moving load train bridge,the influence laws of train load train form,train speed,simply-supported girder span and vertical fundamental frequency on the dynamic response of girder were studied.Combined with the girder vibration acceleration,allowable dynamic coefficient and code requirements,the lower limit of vertical fundamental frequency of prestressed concrete simplysupported girder bridge of 400 km/h high speed railway was determined.The results show that when the span is 24~40 m,the maximum vertical dynamic response of the girder increases with the decrease of the simply-supported girder span,and the fundamental frequency resonance of the simply-supported girder with a span of 24 m is the most significant.The bridge dynamic response caused by CRH3 train load is generally greater than CRH380,with a difference of about 15%.For CRH3 and CRH380 trains with a speed of 400 km/h,the recommended lower limit of vertical frequency of simply-supported girders with a span of 24 m is 5.5 Hz,that of 40 m is 2.7 Hz,and that of simplysupported girders with a span of 32 m is 5.0 Hz and 3.0 Hz respectively.