Taierzhuang Canal Bridge is located on the Zaoxu Line (k307+620) of S244 Provincial Highway in Taierzhuang District, Zaozhuang City, Shandong Province, with a total length of 753m. The whole bridge consists of south and north approach bridges and the main bridge. The approach bridges are 26-hole reinforced concrete T-beams with a standard span of 20m and 2-hole 30ITI prestressed reinforced concrete T-beams. After 20 years of use, the main diseases of the bridge are: 

①There are different degrees of cracks on the surface of the main beam of the approach bridge, and the cracks are mainly distributed in the 10m section of the main beam mid-span and the 5m section near the fulcrum. The mid-span crack spacing is 0.2m ~ 0.61TI, the maximum width is 0.25mm, and its height is generally 110cm, which is greater than half the beam height 65em;

②Most of the supports of the approach bridge have shear deformation and rubber aging phenomenon;

③ The connecting steel plates between the diaphragm beams are broken and welded, and the vehicles are basically in a state of stress on a single beam.

Introducing the Determination of Bridge Disease Reinforcement Measures with Examples

From the analysis of the distribution state and surface characteristics of the cracks, the cracks basically belong to the active structural stress cracks. Especially in recent years, the traffic flow has gradually increased, and the vehicle load has increased day by day. The original design load level is difficult to meet the use requirements. According to the results of the bearing capacity check and load test, the highway management department decided to reinforce and repair the standard span 20mT beam to ensure the safety of highway operation. In the reinforcement design, considering the insufficient flexural strength of the approach bridge, for the convenience of construction and the needs of scientific research projects, the approach bridge is reinforced by sticking carbon fiber sheets.

After the reinforcement calculation and the comparison of the plan, the main beam with the most unfavorable force of the bridge is the side beam. Finally, it is determined that two layers of 200 carbon fiber cloth are pasted on the side beam, and a layer of 200 carbon fiber cloth is pasted on the 2, 3, 7, and 8 main beams. Width 18cm. According to the structural requirements, the bottom layer of carbon fiber cloth is 100cm longer than the top layer, and U-shaped hoops are added at each truncation point to be anchored to prevent peeling. The total cost of the carbon fiber reinforcement project for the 26-hole approach bridge is 692,700 yuan. The original design unit determined the reinforcement plan based on experience and methods, and the total cost of sticking carbon fiber reinforcement was 2.1927 million yuan, which saved about 1.5 million yuan in the bridge reinforcement project and achieved good economic benefits.

Due to the dislocation, cracking, concrete peeling and steel plate corrosion of the diaphragm, the steel plate method is adopted for reinforcement, and the entire diaphragm beam after pasting should be treated with mortar.

The technology of reinforced concrete structure by sticking carbon fiber cloth is a new type of structural reinforcement technology. Due to the unique corrosion resistance of carbon fiber materials, it can be widely used in bridge reinforcement and maintenance in areas with harsh environmental conditions. And the reinforced carbon fiber cloth hardly needs any maintenance work, which reduces the maintenance cost in the later period, which is unmatched by the method of sticking steel plates. Although the initial investment cost is slightly higher, the long-term comprehensive cost is lower than that of the bonding steel plate reinforcement method.