Bridge engineering in capping beam construction?

In bridge engineering, the construction technology of cross reinforcement mainly relies on solid round steel passing through the reserved holes of pier columns, which is the core load-bearing part of the concrete entity of cap and capping beam model. In the process of pouring piers, holes should be reserved in advance. Usually, circular steel holes are reserved in the longitudinal direction of the bridge. The length of this round steel can only be determined after calculating the diameter of pier and the width of I-beam in advance. After the pier pouring operation is completed, the construction personnel should insert the solid round steel into the pre-reserved hole in the next process. In order to maintain the firmness of round steel, nuts should be used to reinforce and fasten it externally. On both sides of the pier supporting iron in the transverse direction of the bridge, the construction personnel need to erect I-beams respectively, and a certain amount of square wood should be laid on the I-beams. These two I-beams are the main load-bearing beams of pier columns, and the square timber is the main system to support the model, and it also plays the role of distribution beam.

2. Analysis of the concrete design of the cross-bar method in the construction of bridge capping beam.

2. Design analysis of1square timber distribution beam

The square timber is the main system to support the model and plays the role of distributing beams. In the bottom construction of bridge capping beam, the layout of square timber is used to bear the surface load brought by formwork operation. In the mountain roads investigated by the author, the square timber is designed as longitudinal long side and transverse short side. The square timber spacing is designed to be 0.5m, and the area is about 20cm× 15cm. According to these data, the surface load borne by each square wood can be calculated. After the transformation steps, the final uniform wiring load is14.2kn/m/m. As can be seen from the figure, in the simply supported beams hinged on both sides of the square wood, the maximum bending moment is about 6.4kN/m, and the interface resistance distance is about 0.00 1m3. Substituting the above data into the section bending formula, it is calculated that the section bending bearing capacity of the square timber is about 6.4MPa, which is obviously lower than the upper limit requirement of the allowable limit of the construction code 17MPa, so the section area and layout of the square timber in this scheme meet the construction requirements.

2.2 load design analysis

When designing the construction load of mountain roads and viaducts by crossing poles, we need to refer to the Code for Design of Highway Bridges and Culverts issued by China. According to the relevant index requirements in the design specification, the total bulk density of reinforced concrete designed for the above viaduct is 26kn/m. ..

2.3 Design Analysis of Solid Round Steel

In the design of solid round steel, it is necessary to consider the close cooperation between supporting iron, solid round steel and pier. In general, the load is transmitted to the solid round steel through the supporting iron, which can be ignored in the bridge design in this paper and regarded as pure shear stress. The load of each solid round steel used in this paper is about 166kN, which is a φ 60 mm model.

3. Concrete implementation steps of cross bar method in bridge capping beam construction

3. 1 reserved channel

When pouring the bridge pier, the construction workers need to seal the steel pipe with a diameter of 70 mm and bury it in concrete in advance along the bridge direction. The location of concrete embedment is usually calculated and determined with reference to the total height of the capping beam support system. At present, in the design of bridges in China, the height of capping beam support system is usually greater than the total height of 80 ~ 100 mm, and the prepared square wood needs to be placed under the wedge when embedded. When the concrete strength of the capping beam reaches the demolition standard, it is necessary to open the lower part of the square wood of the wedge to leave room for demolition and facilitate operation.

3.2 Fastening bolts

The solid round steel is exposed outside the pier, and the construction personnel need to fix it with supporting iron, and tighten bolts on the outside to make the supporting iron closely fit the pier as much as possible. In addition, the problem of moving the supporting iron can be effectively avoided. In our country, the supporting iron is usually processed into arc shape. This design can reduce the probability of pier damage, fix solid round steel and nuts, and prolong the service life of the bridge.

3.3 La I-beam

When the longitudinal beam of I-beam is on the supporting iron, it is necessary to adopt the method of pulling and fixing to ensure the safety of construction work, which can also make the whole structure stress evenly. In the mountainous highway studied in this paper, steel tie rods are fixed on pier columns to pull each other, and the distance between tie rods is generally 2 for cantilever and 3 for pier columns.

3.4 Seal reserved holes

After capping construction, I-beam, bottom die and solid round steel need to be removed. When doing this work, it is necessary to close the reserved tunnel in advance so that the construction can be carried out in sections. For the reserved holes with a diameter of 60 ~ 70 mm, whether this measure is taken has little influence on the stress of the pier. Although there is no impact, in order to ensure the service life of the bridge pier reinforcement and the overall structural appearance, after the demolition operation is completed, the reserved holes still need to be blocked.

For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd