Common diseases of the bridge after it is put into use include surface damage, railing damage, bridge head jumping, corrosion or deformation of components, etc., which pose a serious threat to the overall quality, service life and safety performance of the bridge. For this, it is necessary to comprehensively consider the actual state of the bridge, the bearing capacity and the type of disease, select the appropriate reinforcement technology and construction method, and implement quality control measures for key links to improve the quality of the bridge and ensure the safety of use.

1 Analysis of Common Construction Techniques in Bridge Reinforcement Engineering

1.1 External prestress reinforcement technology

1.2 Bonded prestress reinforcement technology

1.3 Increase beam section and auxiliary members

1.4 Paste steel plate reinforcement technology

2 Discussion on concrete measures to improve the quality of bridge structure reinforcement based on the concept of quality control

2.1 Strengthen the treatment of bridge cracks

Crack disease is a common ill in bridge engineering. When dealing with bridge cracks, it is necessary to focus on the key construction node of grouting nozzle layout. For bridges with large cracks, it is necessary to appropriately expand the spacing of grouting nozzles. At least two grouting nozzles should be arranged at each crack, and the spacing distance should be controlled within the range of 10~15cm. This not only saves construction materials, but also helps to ensure the quality of crack treatment, effectively improve construction efficiency and economic benefits, and enhance the quality of bridge reinforcement.

2.2 Scientific treatment of vacant bearings

Lifting air bags are usually used for venting support. In terms of construction quality control, it is necessary to pay attention to checking the sealing performance of the air bag, and carry out reasonable inflation tests. Stop inflating when the internal pressure of the air bag approaches 0.5 MPa, and inflate again after 8 minutes, until the internal pressure of the air bag reaches the preset air pressure value. And prevent sharp objects or hard objects from cutting the air bag, and promote close contact between the lifting air bag and the beam body, so that the contact area occupies 2/3 of the air bag surface. During the overall construction process, construction personnel are required to closely observe various procedures and construction details. Once problems are found, they should be reported to the superior department immediately. In severe cases, construction should be stopped immediately, and construction personnel should be urged to evacuate to a safe area to prevent blind construction.

2.3 Reasonable use of carbon fiber materials

Carbon fiber reinforced plastic is a composite material processed from carbon fiber materials and resin materials. It has the advantages of stable structure, light weight, strong cold resistance, good corrosion resistance, and good heat resistance. It has both specific strength and specific stiffness. better. In the material preparation process, the quality control of processed materials must be strictly based on the design drawings. For example, ensure that the strength of the selected concrete material is not lower than C15, and ensure the strength and flatness of the base surface of the reinforcement member. In the use of glue, it is necessary to control the flatness of the base glue, the integrity of the main glue and the bonding time of the surface glue mask to enhance the compatibility between different glues. When selecting carbon fiber sheets to be pasted on concrete structures, attention should be paid to controlling the temperature, radiation, and corrosion conditions of the working environment, avoiding long-term construction in a working environment below 5 degrees Celsius and above 60 degrees Celsius, and protecting the carbon fiber sheets jobs. In the process of substrate treatment, in order to ensure that the carbon fiber material and the concrete component are adhered closely, the flatness of the surface of the concrete component needs to be controlled. Polish and repair the surface of the component and the part of the template, and dry the surface after the treatment. In the steel bar treatment process, attention should be paid to the treatment of the corroded parts of the exposed steel bar. According to the size of the crack, the corresponding sealing treatment and irrigation filling technology are selected to ensure that the carbon fiber material and the concrete surface are tightly bonded, and have a good bonding and repair effect.

2.4 The key points of sticking steel plate reinforcement control

The following three quality control points should be paid attention to when adopting the sticking steel plate reinforcement technology:

(1) Material quality control. Based on design specifications, quality control and performance inspection of structural adhesives, edge banding adhesives and other materials are carried out. After entering the site, colloidal materials shall be sampled based on colloidal performance, bonding ability, solid content, and humidity and heat aging.

(2) Quality control of the construction process, including the compactness, flatness, and cleanliness of the concrete component surface to ensure that the surface has a certain roughness, and the steel plate surface is polished, rusted and cleaned. In the process of planting reinforcement drilling, it is necessary to control the drilling position, diameter, hole depth, verticality of the hole and other indicators. Combine the prestressed steel strands and the position of structural steel bars for reasonable adjustment of the drilling position. After the hole cleaning operation is completed, the structural glue is injected into the hole, and the glue injection volume in the hole is reasonably controlled, and the glue is blocked and the screw is fixed. Complete the installation of steel plate, glue injection and exhaust pipe in sequence, and do a good job of sealing around the steel plate. In the process of pressure injection, attention should be paid to the reasonable selection of the injection pressure tank, the control of the pressure injection process and the anti-corrosion treatment of the steel plate, and the quality inspection with a small steel hammer after the injection is completed.

(3) Do a good job in dealing with the quality defects of glue injection. For example, for corner hollowing defects, electric drills and small-diameter drills can be used to seal the edges at both ends of the hollow drum to open holes to the cavity. Use a large syringe to inject acetone and structural glue into the cavity in turn, and close the orifice after the air is discharged. For the defects of the honeycomb hollow drum, it is necessary to remove the steel plate and re-install and inject glue, or add a steel plate to the side for reinforcement to ensure the bonding of the bonding surface and achieve the quality control goal.

3 Conclusion

The structural reinforcement of the bridge plays an important role in extending the service life of the bridge and meeting the needs of transportation. In order to ensure an effective improvement of the quality of bridge reinforcement, it is necessary to combine the types of bridge diseases to reasonably select and process the reinforcement technology. And focus on construction material management, construction team training, the application of new equipment and new technology, construction supervision and other levels to improve quality control, and further achieve the goal of saving costs and improving benefits.