Language: English
New reinforcement bridge technology
prestressed CFRP plate
The new technology of prestressed carbon fiber plate for bridge reinforcement is simple to operate, has a short construction period, obvious economic benefits and good reinforcement effect.
Project Overview
The bridge is a national highway dedicated line project, built in 1999, the bridge beam length is 306.24m. The form of the superstructure is: 2×30m+2×50m+4×30m+20m prestressed concrete continuous variable section box beam. The lower structure adopts multi-column bridge pier, and the abutment adopts pile-column abutment. Use plate rubber support. The foundations are all bored with pile foundations. Design load: 20 tons for steam and 100 tons for one. Bridge deck width: 0.50m (collision guardrail) + 12m (net width) + 0.50m (collision guardrail) = 13.0m.
In May 2012, the bridge was fully tested, and the test results are as follows
The rating of the technical status of the full bridge is classified into four categories-poor condition. Major repairs or alterations are required, and traffic control is carried out in a timely manner.
Through the inspection and calculation of the flexural bearing capacity of the mid-span and the fulcrum section and the shear bearing capacity of the fulcrum and the adjacent section, the existing bearing capacity of the bridge cannot meet the requirements of highway class II load standards, and must be strengthened or rebuilt.
The vibration sensation of the whole bridge is obvious, which is related to the poor overall rigidity of the bridge itself.
Reinforcement design
According to the bridge inspection results, the following reinforcement design schemes are proposed:
①Reinforcement of mid-span bending moment
The box girder of equal section is reinforced with prestressed carbon fiber plate on the mid-span floor;
The variable cross-section box girder is tensioned and reinforced by prestressed carbon fiber board on the side of the web in the mid-span box;
②Reinforcement of negative bending moment of support
It is reinforced with prestressed carbon fiber board on the top surface of the box girder;
③ Shear of bearing
The box girder web is reinforced with a thin layer of high-performance cement composite mortar reinforced mesh (HPFL) on the side of the box girder web, and the box girder vertical web is reinforced with a thickness of 5 cm on both sides;
④50m span stiffness increased
Longitudinal ribs are added on both sides of No. 2, 3 and 4 pier supports of 50m span to increase the rigidity of the bridge beam
Conclusion
The new technology of prestressed carbon fiber plate for bridge reinforcement is simple to operate, has a short construction period, obvious economic benefits and good reinforcement effect. Its successful application on the Zhujindu Bridge shows that this kind of reinforcement method is worthy of popularization and application in similar domestic engineering projects.
