悬拼施工中钢箱梁制造尺寸的确定

摘要

In order to effectively determine the fabrication dimensions of steel box girders to ensure the smooth erection of main beam and make the profile upon completion state meet design requirements,a new method to calculate fabrication dimensions was established by using the calculation results of construction phase. This method is based on the geometry control method,and commences from the unstressed relationship between a new lifting beam segment and its adjacent installed beam segment in cantilever construction. In addition,the fabrication dimensions of steel box girders of the main channel bridge of Jiashao bridge,as the research subject,were determined. The construction practice shown that the main channel bridge construction of Jiashao bridge was going well. The measured data indicated that the profile of the main beam of the bridge upon completion state was smooth,and the maximum elevation error was far less than the prescribed limit values to verify the correctness of the established method.%为有效确定钢箱梁制造尺寸，确保主梁悬臂顺利拼装，成桥后线形满足设计要求，基于几何控制法理论，以嘉绍大桥主航道桥为研究对象，从新起吊悬拼梁段与相邻已安装梁段间的无应力关系着手，提出了利用施工阶段分析结果计算钢箱梁制造尺寸的方法，并按此方法确定了嘉绍大桥主航道桥主梁的制造尺寸。施工实践表明：嘉绍大桥主航道桥主梁安装顺利，合龙后实测主梁线形平顺，最大标高误差远小于规定的限值，验证了该方法的正确性。