The highway construction of our country has developed rapidly in recent years, large span bridge, suspension bridge, cable-stayed bridge design, construction level unceasing enhancement, but the development of the design, the medium span bridge construction level is relatively slow, structure still with simply supported hollow slab and simply supported T beam, some small span bridge with simply supported continuous box beam and cast-in-place continuous beam. Steel box section with good structural performance, which is widely used in modern bridge. Compared with the ribbed plate type section, the box section will have the following characteristics: (1) rigid box girder cross-section torsional stiffness, structure has good stability in the construction and use of the process. (2) the steel box girder is effective against the positive and negative moment reinforcement, and meet the requirements of. To adapt to the structure or component with positive and negative bending moment, such as continuous beam, arch bridge, steel bridge, cable-stayed bridge, cantilever beam, T also adapted to bear moment rigid frame bridge etc.. (3) can be adapted to the requirements of modern construction, such as the cantilever construction, pushing construction, this kind of construction method are the section with the bottom thick. (4) combined bearing structure and the force transfer structure, the component of the force together, at the same time section high efficiency, and is suitable for space prestressed concrete beams, to achieve better economic results. (5) for the wide bridge, the torsional stiffness, the component of the force together, the lateral load distribution across without diaphragm can obtain satisfactory. (6) suitable for construction of bridge to curve, has great adaptability; can well adapt to the arrangement of pipelines and other public facilities. Box section also have some shortcomings, the need for adequate attention by designers, such as thin-walled structure, need to configure the structure of reinforced a lot, this for medium span bridge, sometimes leading to steel quantity than the I-shaped or T section; compared with the fasting truss, structural self weight is larger, so some measures must be taken to in addition, such as reducing weight, box girder construction is more complex.
With the development of economy, but also with the rapid development of highway bridge. The bridge is an important part of the road, city road or railway, is a comprehensive level of national level industry and technology embodies. So that the bridge is one of the symbol of a country. After decades of efforts, both in the scale of construction on our bridge engineering, or in the science and technology level, have been among the advanced ranks in the world. A variety of complete function, beautiful appearance of the overpass, viaduct, extra long span bridge across the Yangtze River, the Yellow River River, such as bamboo shoots after a spring rain frequently built. The bridge is developed with the economic development of the transportation and economy and science and technology are possible. In twentieth Century the world bridge technology development make a spurt of progress, All flowers bloom together., formed the theory system of the design and construction of complete. Our country bridge technology closely follow the development of the world bridge technology trends, and gradually formed a complete design theory, design method, construction technology and scientific research system; built nearly a million bridge engineering, which also includes a lot of eye-catching with bridge engineering world first. Especially since the eighty's of last century, with the rapid development of the national economy, China's construction of Luqiao is developing with high speed and high quality of the hitherto unknown.
The main contents of the design is a Shanghai freeway on ramp design. Design of the three bridge project, were simply supported beam bridge, reinforced concrete steel arch bridge and continuous beam bridge, the recommended scheme for continuous steel box girder bridge. This bridge, bridge length 32+40+32m. The box section beam, Liang Gaowei beam height, the construction method of prefabricated. The piers were double column piers, foundation for the bored pile foundation. Prefabricated steel box girder bridge can save a lot of formwork support, shorten the construction period, accelerate the construction speed, so it is widely used. The advantages of continuous steel box girder bridge is simple to manufacture, good integrity, convenient joint, is the use of a bridge structure form the most common. Bridge deck pavement: selection of reinforced concrete thick 6cm as pavement, asphalt concrete wearing layer and 10cm, 16cm in total thickness. Bored pile foundation of the main bridge and pier 12 phi =1500; bridge pier with double column piers. 上海高速公路匝道连续钢箱梁桥设计+CAD图纸(2):http://www.751com.cn/gongcheng/lunwen_13694.html