短线节段预制拼装桥梁几何线形三维控制方法

Three-dimensional geometric alignment control method for short-line matching segmental precast girder assembling bridge

针对现有预制几何线形控制方法中的不足,提出考虑梁长误差、转角误差、扭转误差和错台误差的几何线形三维控制方法,针对逐孔整跨施工,研究首节段定位方法。以广州轨道交通14号线(40+3×38)m连续刚构桥中的一孔38 m跨为例,采用本文方法对其进行预制阶段和拼装阶段的几何线形控制。研究结果表明:实测主梁轴线偏差最大不超过6 mm,高程偏差最大不超过12 mm,均远小于规范限值,实际拼装线形平顺流畅,充分验证了本文方法的正确性和精确性。该法已成功应用于近4 000片节段梁预制和近200孔桥梁架设拼装的几何线形控制,实践效果良好。

Aiming to solve the shortcomings of the existing geometric control methods, considering all kinds of fabricating errors, such as the error of length and axis angle, the error of torsion angle and faulting of segment ends, a 3D geometric alignment control method was put forward. In view of the span-by-span construction method, a precise locating method was investigated for initial assembling segment. Taking a span of 38 m bridge as example, which belongs to a （40＋3 ×38） m continuous rigid bridge of No.14 Metro of Guangzhou, the method was applied on the geometric alignment control of precasting and assembling segments. The actual results show that the measured axis deviation is no more than 6 mm and the height difference is no more than 12 mm. Both of them are far less than the limiting value in the corresponding codes. And the actual alignment of the bridge is quite smooth. Thus, the correctness and accuracy of the proposed geometric control method is fully verified. Up to now, the control method has been applied to the geometric alignment contrl of almost 4 000 precast segments and 200 spans assembling bridges. The practical effect is good.