In general, there are several ways in the superstructure strengthening of bridge

1. CFRP reinforcement method
2. Bonded steel plate (tendons) reinforcement method
3. Prestressing FRP reinforcement method
4. Enlarging member section and reinforcing reinforcement method
5. Reinforcement method of rebars planting

CFRP retrofitting

The emergence of carbon fiber materials makes the reinforcement technology of civil engineering a step more. Carbon fiber is widely used because of its light quality, corrosion resistance, thin sheet and high tensile strength.
Carbon fiber cloth (film) reinforcement, improve the bearing capacity for beam bridge reinforcement method, especially when the preferred height limited carbon fiber reinforcement method.
(1) strengthening principle of carbon fiber cloth

The flexural reinforcement of reinforced concrete flexural members is to stick carbon fiber cloth to the tensile area of the members to replace or supplement the tensile properties of the steel bar, thereby improving the flexural bearing capacity of the members.

(2) key points of reinforcement design for CFRP

CFRP is used to reinforce old bridges. At present, the general calculation method is to convert carbon fiber cloth to a certain amount of steel according to a certain standard. Then the theoretical analysis is carried out according to the traditional reinforced concrete force analysis model.

(3) construction technology and requirements of CFRP reinforcement

A. preparation before construction

B. base surface processing

C. coating impregnated adhesive

D. paste carbon fiber cloth

E. cover face protection

Bonded steel plate (tendons) reinforcement method

Steel plate reinforcement bonding method is using epoxy resin structural adhesiveto bonding the steel plate or steel on concrete flexural members, and form together, so as to achieve to improve the bending resistance and shear resistance of the component, and reduce the effect of crack propagation.

Prestressing FRP reinforcement method

1.Improve the bearing capacity of bridge structure,has incomparable advantages in large-span beam slab of flexural reinforcement.

2.Significantly reduce deformation of the structure and improve the bearing capacity of structure,decrease the crack width and deflection deformation,and is suitable for large span beam slab of flexural reinforcement.

3.Improve the stiffness of structure ,and make full use of the material performance ,save a lot of materials and engineering cost.

Enlarging member section and reinforcing reinforcement method

When the strength, stiffness, stability and crack resistance of the beam are not enough, the reinforcement method can usually be used to increase the section of the member and increase the reinforcement.

The enlargement of concrete cross section can be adopted as follows: A. thickening bridge panel B. increases the height and width of the beam rib of the main beam

Main points of construction of main reinforcing bar method: A. reinforcement of main steel reinforcement B. connecting long stirrup and restoring concrete protection layer

Reinforcement method of rebars planting

Epoxy mortar for rebar connections and heavy anchoring

Structural connections with post-installed rebar (e.g. extension/connection to walls, slabs, stairs, columns, foundations, etc.)

Structural renovation of buildings, bridges and other civil structures, retrofitting and re-strengthening of concrete members possible

Anchoring structural steel connections (e.g. steel columns, beams, etc.)