1、 Case Review

The "Tacoma Narrows Bridge" was built in 1938, with a total length of 1810 meters. Since the impact of aerodynamics was not tested during the construction, the intermediate wind force is enough to make the bridge shake, which is called "dancing Getty". Four months after its opening, it collapsed and fell into a canyon.

Fortunately, this accident did not cause any casualties.

On August 14, 2018, a highway bridge collapsed in the Genoa region of northern Italy, resulting in at least 35 deaths. According to local media, the reason for the collapse may be due to structural issues with the bridge.

On the morning of November 18, 2019, a bridge near Toulouse in southern Southern France collapsed, causing 1 death and 5 injuries. The cause of the accident was that the truck involved exceeded twice the maximum load capacity of the bridge.

On October 10, 2019, a bridge deck rollover accident occurred at K135 of China National Highway 312 in Wuxi, Jiangsu, across the bridge on Xigang Road. Causing 3 deaths and 2 injuries. After preliminary analysis, the accident was caused by overloading of transportation vehicles.

According to incomplete statistics, there were 85 non seismic bridge collapse accidents in China from 2000 to 2010. From 2000 to 2012, there were 341 bridge collapses in the United States. According to recent data, the number of bridge accidents has shown an upward trend.

2、 Cause analysis

According to the causes of accidents, they can be classified into six situations: water disasters, wind disasters, ship and vehicle collisions, overloading, design and construction errors, and prolonged disrepair. In summary, due to factors such as design, construction, natural environment corrosion, and increased traffic loads, the bearing capacity of bridges is insufficient to meet transportation needs.

Therefore, it is the most economical, safe and environmental protection method to select the appropriate reinforcement technology for the structural reinforcement of existing bridges through standardized and reasonable detection and identification.

3、 Introduction to Carbon Fiber Lminate Reinforcement Technology

Carbon fiber composite materials are widely used for structural reinforcement in the field of bridges due to their advantages such as high strength, high modulus, and corrosion resistance. Among them, the carbon fiber Lminate reinforcement system has unique advantages in controlling bridge cracks and improving bridge bending resistance.

Carbon fiber Lminate reinforcement technology can be divided into passive reinforcement technology (bonded carbon fiber Lminate reinforcement technology) and active reinforcement technology (prestressed carbon fiber Lminate reinforcement technology) based on their different reinforcement forms.

1. Strengthening Technology of Sticking Carbon Fiber Lminate

The carbon fiber Lminate and concrete components are bonded using epoxy adhesive (carbon Lminate adhesive) to achieve the goal of joint stress. For U-shaped bonding, carbon fiber Lminate and carbon fiber cloth are often used in combination.

According to the force calculation, 1.2mm thick high-strength primary carbon plate can replace 5mm thick Q235 steel plate with equal width.

  2. Strengthening technology of prestressed carbon fiber Lminate

By bonding epoxy adhesive (carbon Lminate adhesive) to concrete components and applying pre tensile stress, a new force balance is formed to improve the load-bearing capacity of the structure.

In summary, carbon fiber Lminate reinforcement technology has significant advantages over traditional reinforcement technologies in the bending and crack resistance reinforcement of bridges, especially for the bending and crack resistance reinforcement of large-span bridges. Choosing appropriate reinforcement methods plays an important role in reducing the occurrence of bridge collapse accidents.