Tokyo-based development of carbon fiber composite multi-reinforced prefabricated PC bridge deck
Tokyo Kogyo International Co., Ltd. and Oriental Shiraishi Co., Ltd. jointly developed a prefabricated PC (prestressed concrete) bridge deck “CFCC slab” made of CFCC® carbon fiber composite cable. The product has passed all tests related to structural performance, completed the wheel load running fatigue test, and laid on the actual bridge to enter the practical application stage.
In recent years, in the new laying and renovation of steel bridge decks, the use of prefabricated PC slabs has gradually increased in order to shorten the construction cycle, increase durability and increase production efficiency. The “CFCC slab” is a prefabricated PC slab that uses a carbon fiber composite cable to introduce pre-stress in both the deck support direction and the bridge axial direction. In addition, the use of short fiber reinforced concrete reduces reinforcement and reduces costs beyond prestressing tendons.
Since the carbon fiber composite cable is a corrosion-resistant material, it is not necessary to add an anticorrosive coating layer for protecting the conventional steel bar in the bridge deck used in the saline-alkali environment. In addition, in the production of concrete members, the use of traditional steel bridge decks requires the use of post-tensioning methods, which will eventually leave metal prestressing tendons, and the use of “CFCC slabs” will not leave a metal fixed structure when completed. From the perspective of ensuring durability, reliability and full life cycle (LCC), “CFCC slabs” can be used in harsh saline environments, such as near the coast or in areas where antifreeze is sprayed.
“CFCC slab” reduces the use of prestressed tendons by using short fiber reinforced concrete, but compared to traditional bidirectional PC bridge decks that use steel plates and steel bars, whether it is bending fracture properties (yield strength, toughness) or shear strength The performance is not inferior. In addition, in the wheel load running fatigue test, even if a load equivalent to a value of about 300 times the service value of 100 years is applied, the bridge deck is not damaged.
The “CFCC slab” is about 6% lighter than conventional slabs of the same thickness, making it possible to optimize the design of the decks at the non-slip holes, drains, etc., which may be subject to liquid penetration and cause aging of the deck. Taking the bridge with a length of 240m in the saline-alkali area as an example, the “CCFC slab” is used for the bridge deck renovation project, which can reduce the workload by about 15% compared with the ordinary one-way PC bridge deck. However, overall construction costs will increase by 13% to 22%.
The same aging problems as the bridge deck are also present due to the infrastructure. “CCFC slabs” also have their place in areas such as reinforcement and renovation of infrastructure.