There are several classifications of bridge and tunnel reinforcement methods

Outsourcing concrete reinforcement methods

The outsourcing concrete reinforcement method, also known as the section reinforcement method, improves the strength, stiffness and stability of the component and reduces the crack width by increasing the cross-section and reinforcement of the component. It is used for beam bridges, arch bridges, rigid structure bridges, piers, foundations, etc. , this method can be used for reinforcement when conditions permit. Outsourcing concrete will increase the dead weight of the original structure. Therefore, when formulating the size of outsourced concrete, the structure under the outsourcing component should be considered at the same timeCarrying capacityThis is the premise of whether the outsourcing concrete scheme is established.

Steel plate bonding and reinforcement method

Due to the increase in traffic, the bearing capacity of the main beam is insufficient, or the longitudinal main bar is seriously corroded, or the main beam of the beam plate bridge is seriously cracked. At this time, the steel plate can be bonded and anchored on the tensile edge or weak part of the concrete structure with adhesive and anchors, so that it becomes one with the structure and replaced with steel plateAdditional reinforcement, to improve the bearing capacity and durability of the bridge.

ShotcreteReinforcement method

First, the anchor bar is implanted into the structure of the part to be reinforced by the method of reinforcement, and then the reinforcement mesh is hung, and then a certain thickness of concrete is sprayed to form a combined structure that is jointly stressed with the original structure. Shotcrete is a type of reinforced concrete that will beFreshly mixed concreteWith the help of injection machinery and compressed air, it is sprayed at high speed through the nozzle onto the spraying surface of the anchored steel bar, and then solidifies and hardens.

Change the reinforcement method of the structural stress system

This method of reinforcement and transformation is to improve the bearing capacity of the bridge by changing the stress system of the bridge structure. The basic principle is to lowerControl sectionThe internal force is reinforced. For arch bridge reinforcement, the stress state of the simple arch can be converted into the stress state of the arch-beam composite system through the method of system conversion, that is, the building on the arch can be converted into a beam structure, and the stress state of the arch-beam composite system is more uniform than that of the simple arch. In addition, for old bridges built on arches, the reduction in the load brought about by changing the arch to a beam arch is very significant.

In vitroPrestressed reinforcementlaw

The in vitro prestress reinforcement method is mainly used for beam bridges (includingSimple support beams, cantilever beams, continuous tie beams, etc.). ) exceeds the limit. By applying external prestress to the old bridge, the purpose of reducing or eliminating cracks, reducing the deflection of the beam, and improving the stress state of each section of the structure can be achieved. The basic principle is to set it outside the beam bodySteel tie rodOr struts, which are connected to the reinforced beam body through anchoring, and then apply prestress to force the tie rod to be forced, so as to change the internal force distribution of the original structure, reduce the stress level of the original structure, significantly improve the bearing capacity of the structure, and reduce the deformation of the structure, so that the crack width is narrowed or even closed.

Reinforcement method to reduce the dead weight on the arch

Reducing the dead weight on the arch is also a means to adjust the dead load distribution on the arch. Although their purpose is to restore and improve the carrying capacity of the original bridge, the starting point and application occasion are different. Adjusting the dead load distribution on the arch is adjusted by adjusting the dead load on the arch for the case of excessive deformation of the main arch circlearch axisand pressure lines. Reducing the weight of the building on the arch is mainly for some hyperbolic arch bridgesFoundation bearing capacityIn low cases, this measure reduces the requirements for the bearing capacity of the foundation.

Composite Reinforcement Technology (FRP)

It is composed of two parts: fiber and mesh resin. At present, there are three commonly used composite materials: E-glass fiber, carbon fiber, and aramid fiber, among which carbon fiber (CFRP) material is the most widely used.

adoptedCarbon fiber cloth reinforcementBridge and building structure repair technology is a new type of structural reinforcement technology, which is based onResinsThe cementing material is the matrix, and the carbon fiber cloth is pasted and solidified on the surface of the concrete structure, and the high strength of carbon fiber is usedmodulus of elasticityTo achieve the purpose of reinforcing and reinforcing concrete structures and improving the stress condition of the structure.

Wire winding reinforcement method

The wire winding reinforcement method is a direct reinforcement method that winds the annealed steel wire on the surface of the reinforced member to restrain the concrete of the reinforced component, thereby improving its bearing capacity and ductility.

This wire winding reinforcement method has the following advantages: first, it improves the bearing capacity of the oblique section of reinforced concrete components; The second is to improve the positive cross-sectional bearing capacity of the axial compression member.

SRAP reinforcement method

The SRAP reinforcement method is a new bridge reinforcement method that introduces the concept of prestress. It uses the high strength characteristics of SR reinforcement materials and the characteristics of AP resin mortar to prevent corrosion and waterproofing, and strong adhesion, and applies prestress to SRAP high-strength materials through special methods, so as to achieve the reinforcement of the bridge. The application of prestress anchored the expansion bolt at both ends of the bottom of the beam, and the two ends of the soft steel wire were fixed to the expansion bolt with spiral buckles, and the prestress was applied by tightening the screw buckle in the opposite direction.

Bridge deck reinforcement layer reinforcement method

The original bridge deck paving is chiseled or chiseled, and then a certain thickness of reinforcement layer is laid to increase the effective height of the main beam and improve the lateral distribution capacity of the bridge load, so as to improve the bearing capacity of a single girder or the overall bearing capacity of the bridge structure.

Anchor spray concrete reinforcement method

The reinforcement method transformed from tunnel construction is mainly used for the reinforcement and maintenance of concrete beams with insufficient shear strength caused by the small size of the fulcrum section.

Adding horizontal connection reinforcement method Increasing horizontal connection is also a more popular reinforcement method in recent years. This method improves the lateral distribution law of the load of the superstructure by adding the lateral connection of the bridge, so as to achieve the reinforcement method to improve the overall bearing capacity of the structure.