Structural Reinforcement Of Beams And Slab Concrete

A commercial building is located in the center of a prosperous commercial street in the city, with 22 floors above ground and two floors underground, with a total area of approximately 12,000 square meters. The building was built in 2003. After a long period of use and environmental factors, the concrete beams, columns, and slabs of the overall structure of the building have experienced varying degrees of aging and damage, and the stability and safety of the overall structure have continued to decline. The concrete structure must be reinforced to improve the stability and safety of the building. After on-site survey and measurement and concrete material inspection, it was determined that the concrete structure should be reinforced, and the concrete structure reinforcement construction plan was formulated based on relevant data. The construction of the project started in May 2015, and the project was completed in July 2016. After passing the quality inspection, it was put into use normally.

The beams and slabs of the building were reinforced with concrete.

After careful survey and analysis, the construction method of increasing the cross-sectional area of the beams and slabs of the construction project was adopted to strengthen the construction method, and the construction plan of concrete reinforcement was formulated.

First, clean up the structure layer, sweep away all the debris and dust, and clean the surface of the concrete structure to expose the coarse aggregate. Then select the concrete bonding surface and concrete materials according to the stress calculation results of the construction project structure. Exposing the coarse aggregate of the structural layer can effectively enhance the roughness of the bonding surface between the new concrete and the old concrete. To ensure the flatness of beams and slabs, the construction is also more convenient, so that the unevenness can be controlled within the allowable error range.

For structural beams, the thickness of the concrete interface should not exceed 6mm. The design of the board is not more than 4mm. In addition, a number of grooves were removed for the pouring surface of the concrete structure to treat the corners and corners of the concrete structure to ensure that there is no obvious unevenness in the original structure. Secondly, after the overall cleaning is done, the remaining impurities are thoroughly removed, and the short cut of the contact surface is ensured. The rust removal treatment is performed on the structural surface again, including the steel bars of the new concrete structure part and the old concrete structure part. For the parts with more severe corrosion of steel bars, the components must be welded after disassembly, and the welding construction must be carried out in strict accordance with the relevant procedures to prevent quality problems. The plan of this project is set up as divisional and staged construction, the main purpose is to reduce the damage of heat to the steel bars.

For the partial reinforcement of the pillars of the project, due to the large space of the construction project, there is no need to take up space and area too much. Therefore, when formulating the column reinforcement construction plan, the construction technology of increasing the cross-sectional area and the carbon fiber structure reinforcement technology are adopted. The number of steel reinforcements of the building column has been increased to make the cross-sectional area larger, the rigidity and the bearing capacity stronger, so that the stability and safety of the column concrete structure has been greatly improved. Moreover, after increasing the cross-sectional area, the seismic resistance and durability of the column are also well strengthened.

In order to ensure the practicability of the construction project and provide drivers with a good passing experience, in the actual construction process, the construction company needs to arrange specialized personnel to do a good job in the surface treatment of the concrete, and do a good job in the maintenance work as required. In the actual construction process, the construction personnel use necessary mechanical equipment to flatten the exposed steel fibers in the concrete area. In this process, the steel fiber is processed scientifically by means of metal rolling and other methods. For cutting joints on the surface of concrete structures, a slitting machine should be used to reasonably control the depth of the notches in the concrete structure to avoid the occurrence of too shallow or too deep notches. In the curing process, we can fully learn from the curing experience of ordinary concrete, and adopt the method of regular watering to ensure the wet state of the concrete, and at the same time control the curing cycle to one week. In order to avoid construction risk points, construction companies need to arrange personnel to carefully do pavement cleaning, steel bar laying and other related work to effectively enhance the construction quality of construction projects. Specifically, in the construction process, it is necessary to do a good job of cleaning the floating concrete on the concrete surface. In this way, the firmness of the connection between the steel fiber laying area and the bridge deck can be ensured. Avoid the appearance of construction quality problems, triggering subsequent construction quality problems, and affecting the rational use of construction projects.

In addition, due to the different scope of increasing the cross-sectional area, there are also certain differences in the specific construction methods and construction techniques. Usually there are several construction operation techniques such as single-sided thickening, double-sided thickening and outsourcing. This project mainly adopts outsourcing method. First of all, after cutting and cleaning the surrounding concrete of the column, the new and old concrete contact surfaces are arranged in accordance with relevant standards to ensure the quality of construction. Finally, the new steel bars are arranged around the concrete column, and the formwork is supported, and then the concrete pouring construction is carried out.

For the external structure of the project, the structural bonding steel reinforcement technology is adopted. According to the design drawings combined with the actual size of the site building structure for steel plate processing. Determine the position of the steel plate according to the actual anchoring position on the concrete surface, and determine the diameter of the grouting and grout outlet holes at the upper and lower ends of the steel plate to be 5mm. The steel plate should be drilled in advance, and the diameter of the anchor bolt should not be larger than 2mm, and the surface of the steel plate should be polished to ensure that the surface is free of dust and oil. The main construction process includes positioning and laying out, concrete structural surface treatment, steel blanking to make structural surface treatment, pre-sticking, fixing, through bolt anchoring, and maintenance.

In addition, carbon fiber structure reinforcement technology was used in some parts of the project. It is mainly used in the reinforcement of the shear-resistant part of reinforced concrete beams and columns and the seismic reinforcement of concrete columns. The beam and slab members are tensioned and pasted with carbon fiber sheets for bending reinforcement. The fiber direction is the same as the tension direction of the reinforcement position. The beam and column members are reinforced by shearing with closed pasting and U-shaped pasting. Through this treatment, the entire concrete reinforcement effect meets expectations.