There are mainly the following 5 technical ways to strengthen and reform bridges at home and abroad.

1. Strengthen weak components

For weak components on the bridge that have serious defects or cannot meet the requirements of safe load-bearing due to the passage of heavy vehicles, new materials (sprayed concrete, concrete, steel plate, glass fiber reinforced plastic, steel bar or carbon fiber) are usually used to increase the main beam or main arch ring section. . Use high-grade cement mortar or epoxy resin cement mortar to seal and fill cracks, add external post-tensioned prestressed tendons, apply external prestress, or use chemical adhesives to paste additional components for reinforcement.

2. Add auxiliary components

When the bearing capacity of the bridge is insufficient or the bridge is damaged due to various reasons, new load-bearing members can be added to the original structure, such as longitudinal beams, cross beams or arch ribs. New prefabricated components can also be used to replace components that have serious defects on the original structure and are not easy to repair. When replacing components, sufficient temporary supports must be provided and reliable technical measures must be taken to ensure the safety of the entire structure during construction.

3. Change the structural system

Changing the structural system is mainly to use the continuous action of beams or the combined action of beams, slabs and arch beams to change the stress system of the structure, improve the stress condition of the structure, and improve the ability of the bridge to withstand live loads. For example, the simply supported beam is changed to a continuous beam, the hinged connection is changed to rigid connection, and the single-span beam is changed into a multi-span structure by using auxiliary piers and brackets. And cast a layer of reinforced concrete slab on the arch bridge deck to convert the arch system into a beam system, etc.

4. Reduce dead load

Reducing the dead load of the superstructure of the original bridge can improve the stress condition of the original bridge and increase the ability to withstand live loads. Especially when the bearing capacity of the bridge foundation is limited and cannot meet the requirements of strengthening the superstructure and increasing the bearing capacity of the live load, it is an economical and effective measure to reduce the dead load of the bridge to improve the capacity of bearing the live load. For example, the solid web arch bridge is converted into a hollow arch bridge, and the packing on the arch is replaced.

5. Reinforce piers and foundations

A considerable part of bridge defects and diseases are caused by piers or foundation problems. For this type of bridge, measures such as reinforced concrete hoop sleeves, reinforced concrete tie rods and steel tie rods to apply external prestress, additional pile foundations and jacking methods are usually adopted to strengthen the bridge piers and foundations. Improve the bearing conditions of the piers and foundations, and increase the bearing capacity of the bridge.

Among many bridge reinforcement methods, prestressed carbon fiber plate reinforcement is a very popular form in recent years. It can not only repair structural deformation and close cracks, but also greatly improve the utilization rate of carbon fiber materials and greatly enhance the ultimate bearing capacity of components.