黄大铁路黄河特大桥顶推施工分析与监控技术

针对黄大铁路黄河特大桥连续钢桁梁多点同步顶推施工,利用倒拆法建模计算顶推施工全过程,找出主桁杆件在支点处的最大应力值以及导梁悬臂端变形规律和最大变形值,确定出全过程施工中的最不利工况为M2工况;设置变形监测点,监控导梁前段竖向位移变形,实测值基本与理论值吻合,施工线形可控;在M2工况中,将主桁和导梁自重荷载乘以1.35的放大系数,计算主梁在导梁悬臂140m,悬臂160m和导梁上墩20m后的主桁杆件的应力值,并在主桁上设置24个监测点监测杆件应力值,对比发现实测值均略小于理论值,施工过程中材料强度储备是安全可靠的。作为国内最大跨度的平行弦桁架桥顶推成功,对其他同类大跨度桥梁顶推施工具有较高的参考价值。

Pushing Construction Analysis and Monitoring Technology of the YellowRiver Super Large Bridge on Huang-Da Railway

Aiming at pushing construction with multipoint synchronization of continuous steel truss girder of the Yellow River Super Large Bridge on Huang-Da Railway,modeling and calculating the whole process of pushing construction by using the method of demolition,the maximum stress value of the main truss member at the fulcrum and the deformation law and the maximum deformation value of the cantilever beam were found,it was determined that the most unfavorable condition in the whole process was M2 condition;the deformation monitoring points were set up to monitor the vertical displacement deformation of the front section of the guide beam,and the measured values were basically in agreement with the calculated values,construction was in linear-control;in the M2 condition,the dead load of main truss and guide beam multiplied by amplification coefficient of 1.35,the stress values of main truss member after the main beam in the cantilever beam 140 meters,cantilever 160 meters and guide beam up pier 20 meters were calculated,and on the main truss,24 monitoring points were set up to monitor the stress value of the member,comparing the calculated values with the measured values,it was found that the measured values were slightly less than the theoretical values,the material strength reserve was safe and reliable in the construction process;as pushing success of the largest span parallel chord truss bridge in China,it was of great reference value for the pushing construction of the same kind of long span bridge in the future.