The first single span aluminum bridge officially hoisted in the domestic land

On December 27, 2017, the longest span aluminum bridge in China - the overall lifting of the main girder of the south and north pedestrian bridges in Beijing's Dongdan intersection was officially launched. Among them, the south flyover was hoisted at 0:00 am on December 27, 2017 and hoisted at 0:00 on the 28th North flyover. It is expected that the aluminum bridge will be officially put into operation in mid-to-late January 2018.

It has been learned from the Beijing Municipal Commission of Transportation Committee that the south and north pedestrian bridges of Beijing's Dongdan intersection were established in 1999 and the original landscape effects and functions of old bridges can no longer meet the existing needs.

According to the person in charge of Beijing Urban Road Maintenance and Management Center, the Beidou Beidou bridge of the flyover project is located north of Dongdan intersection and crosses the north of Dongdan. The original bridge is a steel structure bridge, which is an aluminum alloy truss structure after transformation. The entire bridge 58 meters long, full width of 3.85 meters, span of 52 meters single span, when completed will become the largest domestic single span aluminum truss flyover.

Dongdan Nantianqiao is located south of Dongdan intersection. The original bridge is also a steel structure bridge which stretches across Chongwenmen Avenue. After the transformation, the single-span 47.5-m aluminum simple-truss bridge is adopted.

In order to reduce the impact of construction on the underground pipeline and subway operation in the bridge area, this overhaul takes full advantage of the light weight of the aluminum alloy structure, retains the foundation of the old piers, picks up the piers, and the span is the same as that of the original bridge Save the cost and construction period, at the same time provide a new idea for the transformation of the old bridge in the future.

It is reported that the maximum single-span span of the project reached 52 meters, if the conventional components, truss height will reach 5.7 meters, a greater impact on the surrounding landscape. In order to effectively reduce the truss height, the main truss innovative use of U-shaped profile, the size of the structure and rod thickness are the most aluminum bridge.

Through the application of U-shaped profile, the single span of Beidiao Beidou bridge is 52 meters and the height of mid-span truss is only 4.8 meters. Previously, Chongwenmen Avenue North Bridge also adopted the same profile, single-span 47.5 meters, truss only cross high 4.3 meters, effectively reducing the overall height of the truss.

Taking into account the strength of the material, ductility, environmental protection, regeneration and corrosion resistance and other characteristics of the two bridges are used in the transformation of high-strength aluminum alloy material used as a bridge force structure. According to the person in charge of the project, aluminum bridge is light weight, only two-thirds of the original weight of the bridge, about 70 tons, the original structure and the underlying infrastructure without demolition, without reinforcement, can be reused directly, not only to reduce lifting The difficulty at the same time saves investment and reduces the construction cycle. In addition, the surface of the aluminum alloy is smooth, the color is not discolored for many years, the material recovery rate is high, the reprocessing cost is low, the alloy can be completely recovered and the salvage value recovered is 70% of the original price.

In addition, the aluminum bridge can also form a protective film on its own, in wet or acid, alkali environment has strong corrosion resistance, life during use without consideration of post-preservation maintenance, thus solving the major problems of the bridge structure corrosion.

The official said that the traditional installation of flyover bridges, the need to banding steel in the field, installation of templates, pouring concrete, demolition of the template, concrete conservation and many other work, such as only the night of concrete pouring and other work will have noise, vibration Concrete trucks frequently move in and out, which may have an impact on the surrounding social traffic and residents' normal life.

However, the reconstruction of Dongdan North-South Flyover has resulted in 797 structural members of the main bridge of Dongdan North Flyover, 2754 structural members of flyover ladder, 476 connecting plates, 727 structural members of the main bridge of Dongdan Nantianqiao, Pieces of 2774 pieces, 416 pieces of connecting plate, all the components of all factory production, on-site assembly, both to simplify the construction process to speed up the installation, but also reduce the various construction site pollution, etc., is a typical green construction to minimize the public Impact.

Up to now, the Chang'an Avenue comprehensive renovation project starting from 2016 has completed the main renovation of 27 pedestrian crossings (including Qianmen No.1 and No.4 lanes) and between the two gates of Chang'an Avenue (Jianguomen-Fuxingmen) Square meters of the pedestrian renovation work. The person in charge also pointed out that with the completion of the Dongdan flyover, the entire project came to an end, reinstalling Chang'an Avenue overall style is beautiful and beautiful, but also harmonious and surrounding landscape harmony, seamless, filling "solemn, steady, heavy , Atmosphere ", enjoy the" China First Street "in the world.