独柱支撑匝道桥抗倾覆验算汽车荷载研究

Study of Truck Load for Overturning Resistance Checking Calculation of Single-Column-Supported Ramp Bridge

为减免独柱支撑匝道桥倾覆事故的发生,对该类桥梁抗倾覆验算汽车荷载进行研究。通过对国内外相关规范汽车荷载的比较、已有该类桥梁倾覆事故的汽车荷载调查分析、重载交通汽车荷载模式下该类桥梁倾覆效应的研究,得出:对于重载交通线路,《公路桥涵设计通用规范》(JTGD60-2004)汽车荷载计算的桥梁倾覆效应小,安全度不足,且随着桥梁联长的增长,安全度降低。建议在计算该类桥梁倾覆效应时,汽车荷载以加载总量为主要控制指标(可采用控制单车道折算线荷载集度的方式),具体数值应根据实际条件,就当地发生重载交通的程度确定。

To minimize and avoid the overturning accidents of single-column-supported ramp bridge, the truck load for overturning resistance checking calculation of the bridge of such type is studied. On the basis of comparison of the truck loads in the relevant domestic and foreign codes, investigation and analysis of the loads in the existing overturning accidents and study of the over- turning effect of the bridge under the truck load of heavy-load traffic mode, it is concluded that for the heavy-load traffic route, the calculated overturning effect of the bridge according to the truck load in the General Code for Design of Highway Bridges and Culverts （JTG D60-2004） is little, the safety degree is insufficient and with the increase of the continuous unit length of the bridge, the safety degree will be decreased further. It is therefore proposed that in the calculation of the overturning effect of the bridge, the total amount of loading should be taken as the major control index （the way of controlling conversion line load intensity of a single, lane may be uti- lized） for the truck load and the specific values should be determined according to the actual conditions and degree of occurring of the heavy-load traffic in the locality.