m刚构桥角区施工期间支架及上弦箱梁的受力分析.docVIP

 PAGE 5 .. 精华. 290m刚构桥三角区施工期间支架及上弦箱梁的受力分析 郭吉平1 韩洪举2 (贵州路桥集团有限公司，贵州 贵阳 550001) 摘 要：北盘江大桥主桥为(82.5+220+290+220+82.5)m预应力混凝土斜腿连续刚构桥。受下弦梁段浇筑、扣索张拉、预应力张拉等工序影响，该桥三角区受力复杂。针对此问题，结合三角区施工工艺，采用通用有限元软件建立三角区模型，分别对不考虑下弦箱梁变形及扣索和上弦箱梁预应力张拉影响、不考虑下弦箱梁变形及扣索张拉影响、考虑各工序影响的三角区支架及上弦箱梁进行全过程受力分析。分析结果表明，扣索张拉及下弦箱梁变形对上弦箱梁受力影响较小；随着扣索的张拉，各排支架轴力增大；但随下弦箱梁浇筑、上弦箱梁预应力筋张拉，各排支架轴力又将有所降低；受上弦箱梁预应力筋的张拉影响，第2~8排钢管支架在整个三角区施工过程中出现了脱空现象。 关键词：290m刚构桥；三角区；施工支架；扣索；上弦箱梁 The Stress Analysis of Construction Frame and Top Chord Box Girder during the construction in Triangle Area of a 290m Rigid Frame Bridge Guo Jiping1 Han Hongju2 (Guizhou Road Bridge Group Co., Ltd.，Guiyang 550001，China) Abstract： The main part of Beipanjiang bridge is a (82.5+220+290+220+82.5)m prestressed concrete continuous inclined leg rigid frame bridge. By the influence of pouring down chord box girder, tensioning buckle cable and prestressed reinforcement tension, there is a complicated loading condition in the triangle area. To solve this problem, combining with triangle area construction technology, using general finite element software to establish the triangle model, moreover, the whole process analysis of triangle area stand and the top box girder was made under the following three occasions, not considering the deformation of down chord box girder and buckle cable and top chord prestressed reinforcement tension influence, not considering the deformation of bottom chord box girder and buckle cable tension effects, considering the impact of each process. The results showed that the buckle cable tension and deformation of the down chord box girder had less effect on the force of the top chord, as the buckle cable tension, axial forces of each stand line increased. However, with the down chord box casting, the top box tendon tension, the axial force of each stand line dropped slightly. With the effect of the top box girder tendons tension, void phenomenon of 2 to 8 steel frame emerged during the whole construction process of triangle