Research on closure jacking force of continuous rigid frame bridge based on linear programming method(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2017年05期
- Page:
- 65-72
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Research on closure jacking force of continuous rigid frame bridge based on linear programming method
- Author(s):
- WU Feng; WANG Bin; SONG Xu-ming; CHENG Li-juan; ZHAO Li
- 1. Weifang Municipal Engineering Design & Research Institute Co., Ltd., Weifang 261061, Shandong, China; 2. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China; 3. Hunan Provincial Communications Planning, Survey & Design Institute, Changsha 410008, Hunan, China
- Keywords:
- bridge engineering; closure jacking force; linear programming method; continuous rigid frame bridge; iterative calculation
- PACS:
- U444.45
- DOI:
- -
- Abstract:
- In order to determine the optimal solution of closure jacking forces of multi-span continuous rigid frame bridges, a multi-objective linear programming was used to calculate the jacking force by selecting a multi-span continuous rigid frame bridge as the engineering background, the jacking force of each closure as design variables, the section stress at the top and bottom of piers as the objective function and the section stress of piers during the process of jacking as constraint conditions. The influence of jacking forces on creep of concrete of the main girder was neglected and on creep of concrete of the pier was considered. And the nonlinear optimal solution was obtained by linear iterative calculation. The advantages and disadvantages of the two jacking plans (the number of jacking forces were three and two in the first and the second plan, respectively) were compared in the end. The results show that the calculation converges after four iterations and the procedure is proved to be quick and convenient for design, while considering the creep effect of closure jacking force, stress variation of the main girder is relatively small, while stress variation of the pier varies greatly. The jacking force applied before closure has relatively little influence on internal force of the main girder, and can also efficiently adjust stress of the pier, so that distribution of stress at the upper and lower edges of the section is uniform under load effects of completed bridge state. When the actual closure temperature is different from the designed closure temperature, stress of the pier can be reached to an ideal state by adjusting jacking forces. While adopting the second plan, three independent frame structures are formed, which have the larger integral rigidity and are easy to maintain stability during the jacking process. Although the jacking force is increased, the jacking times are reduced. Overall, the second plan is better than the first one.
Last Update: 2017-10-16