Construction of an epoxy resin carbon fiber compos

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France has built a cable-stayed bridge made of epoxy resin and carbon fiber composite materials

France has built a cable-stayed bridge made of epoxy resin and carbon fiber composite materials

April 26, 2005

a hybrid bridge with a span of 110m and no other support in the middle. Its suspension cables are made of carbon fiber composite materials and coated with high-density polyethylene (PEHD) sheath

Laroin is a small city in the southwest of France, not far from the famous jourancon hills. The town plans to build a water sports base on the original sand mining ground. But if you want to go to the base, you must cross the fast flowing river (1egavce Du PAU). Lajuan municipal government decided to adopt the traditional scheme to build a three span pedestrian suspension bridge (the three spans are 32m, 46m and 32m respectively). If the technical scheme is implemented, two piers must be built and the foundation of the pier must be built in the water. However, due to the rapid and unpredictable flow of the Po River, the hydrological environment is very complex

1 a bridge without underwater support

freyssinet of Groupe Vinci has been interested in building a long-span cable-stayed bridge without intermediate piers for many years. The company proposed another technical scheme, that is, to build a reinforced concrete bridge to cross the river channel with a single span of 110m. The local administrator showed great interest in this proposal and was willing to accept innovative solutions. On this basis, fresinai decided to adopt more innovative technical solutions and proposed the use of carbon fiber materials. This material is rarely used in public works. It is the first time in France, and probably the first time in the world, that this new application has aroused entrepreneurship. Norway, Switzerland and Scotland have all done experiments, but they are all used in individual cases. They have never been used as all the cables of cable-stayed bridges. New materials for bridge construction are developed in cooperation with soficar. Softcar is a company that specializes in manufacturing carbon fiber products. It is impossible to supplement the data. It has a production plant several kilometers away from La Juan city. In actual use, the 16 cables that undertake the single span cable-stayed bridge are divided into four groups of 2x2, with a length of 20 ~ 49m. Each cable is composed of 14 ~ 2L rope bundles with a diameter of 6mm, and each rope is composed of a rope bundle with a diameter of 5 ~ 7 μ M fiber and epoxy resin matrix, and the entire pulling cable is isolated from the outside by the protective high-density polyethylene sleeve

2 innovative anchoring technology

the main advantages of high-tech stay cables are that they will not creep and corrosion, have high strength and light weight. Carbon is an almost elastic material, four times less dense than steel (1.5 to 5.8). Therefore, the pulling cable is easy to be used for installation, but it should be handled with great care, because the compressive strength of carbon fiber pulling cable is small, and it is necessary to avoid cutting collision, otherwise it will cause damage. Because of this "blank" in mechanical strength, one of the difficulties encountered by carbon fiber pull cable technology is that when the pull cable is anchored, its end can not bear any extrusion, because the friction performance of synthetic fiber is much worse than that of steel. Fresinai company has conducted research, and finally adopted an innovative anchoring technology, which combines the effect of conical clamping with the effect of bonding friction. The sealing of the anchoring part is ensured by the sealing cap system, which is also filled with paraffin so that some stay cables can be removed in the future. This is an important detail, because the bridge project is actually a physical size test product to verify the research results made by the laboratory. Through this project, the performance of carbon fiber materials can be proved on the spot

3 main structural features of cable-stayed bridge

the deck of lajuan cable-stayed bridge consists of two longitudinal hea340 profiles. The distance between the two profiles is 3.2m, and a series of bridge deck structural materials hea160 are also included. The spacing of structural materials is 2m. The main beam of the bridge is assembled with bolts. The metal frame supports the bridge deck with a width of 2.50M and a thickness of 0.10m. The transverse rigidity is ensured by the reinforcing plate of the st Andreas cross. The reinforcing plate is made of angle profiles. The whole bridge body is supported and suspended by inter span stay cables. All stay cables are concentrated on two anchor ends, which are fixed on two inverted V-shaped metal bridge towers with bolts. The structural tower up to 20m is composed of two supporting feet (15mm thick steel pipe) with a diameter of 630mm. The supporting feet are anchored on the cement abutment through the prestressed installation plate. The abutment is based on micro piles. A traditional cable arriere (19 strand T15 cable wrapped with HDPE sheath) is connected to each anchor end. The other end is fixed in the reinforced concrete block poured on the ground through four fixed screw piles to ensure the stability of the bridge tower

4 physical size test model

carbon fiber materials began to be used in old building renovation projects only a few years ago. Most of the actually used materials are carbon fiber synthetic fabric materials or sheet materials. To strengthen the structure. The price of this synthetic material is still quite high. Only because it is simple and convenient to use (light weight, convenient for storage and cutting), it is necessary to use it. Moreover, it can be used in complex pipelines (especially hospitals) without interrupting the use of existing facilities. In the field of bridge engineering, technological standards are being formulated. Before lowering the material cost, this material is currently light in weight. Therefore, it can only be applied to bridges with large span, such as the Detroit de messine bridge. Therefore, the lajuan suspension bridge is like a model in the size of a real object. Through this project, fresinai company can confirm the long-term performance of this new material, with a view to developing into an offshore construction project through this project as an example. As the oil reserves are becoming less and less, some oil companies have begun to exploit the oil in ultra deep deposits, and sometimes the drilling depth will exceed 1500. At this depth, the steel pipe traditionally used to anchor the oil production platform has reached the limit, so carbon fiber cable can be used to replace it

cable stayed bridge in La Juan, France (photographer: Francis vigouroux)


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