The role of gantry cranes in the construction of subway projects

 In urban infrastructure construction, subway construction is a very important livelihood project. For developing countries, the construction of urban subways will greatly improve the convenience and happiness of citizens' lives, and will also better promote the economic development of cities. As a global crane supplier, Dongqi will explain the role of gantry cranes in subway construction today.

The composition and classification of gantry cranes

The gantry crane is a bridge-type crane device that is supported on the ground track by the outriggers on both sides and performs the lifting function. As a more commonly used lifting equipment, the gantry crane is mainly composed of a gantry structure, a vehicle operating mechanism, a trolley that undertakes the lifting function, and related electrical equipment. According to different application environments, its structure is also refined, but in general, the support module, the lifting module, and the electrical module are its important components. As an important part of the gantry crane, the gantry crane is composed of upper and lower parts, including the upper bridge, outriggers and lower beams. In the actual application process, in order to further expand the operating range of the gantry crane, the main beam of the gantry crane is often further set so that it can be extended to one side or both sides to form a cantilever structure to achieve the purpose of expanding the operating range. . In addition to expanding the working range through the cantilever design, it can also expand its working space by using a trolley with a boom.

According to the scope of application, gantry cranes are divided into ordinary gantry cranes, hydropower station gantry cranes, shipbuilding gantry cranes and container gantry cranes. Different types of gantry cranes complete their hoisting functions according to their applicable operating environment and space.

Research on application of gantry crane in subway construction

In order to achieve a better application effect, when designing the elevated section of a section of Metro Line ⒉ in N City, it is designed as a prefabricated U-beam. The terrain of the construction section is relatively flat, and the buildings on both sides have no impact on the beam erection operation. Therefore, in order to better ensure the construction progress and construction quality, professional beam manufacturing enterprises will prefabricate the U-shaped finished beams required for the project, and After delivery to the project site, the project team decided to use a gantry crane for the erection and construction of the U-beam.

Construction effect of gantry crane

Construction process: In order to ensure the smooth implementation of the project, for the U-shaped finished beams, a special tire-type beam transporter is used to transport and feed the finished beams. At the same time, gantry cranes are used for beam erection operations on the construction site. In the implementation, two 100 ton gantry cranes will be used for cross-line arrangement, so as to realize the joint lifting of the U-shaped finished beam, and then drop the beam to the jack for erection. The specific steps of framing are as follows:

1. Before erecting the finished beams, set up access roads on the construction site to facilitate the entry of related vehicles. At the same time, the special rails for gantry cranes are laid according to the needs of gantry cranes. After the special track is laid, in order to ensure safe operation, the gantry crane needs to carry out a load test on the track under no-load condition to ensure the applicability of the special track for gantry crane and lane change, and at the same time, test the related equipment of the gantry crane.
2. The beam transporter transports the finished beams to the designated position under the gantry crane, and the installation and setting of the spreader are carried out by professionals. After installation, the single machine is lifted for 10cm, and the inspection of the equipment and the beam condition is stopped. After the inspection is completed, the double machine is lifted.
3. Install the rubber support. Before construction, pre-embedded steel plates are set at the bottom of the beams, and bolts are used to fix the supports into the steel plates. During the installation of the support, make sure that the upper and lower bottom plates are aligned with each other, and the center line of the support is within the allowable deviation.
4. After the beam body is raised to the design height, it is moved laterally and the beam is dropped. Drop the beam to 2cm above the pre-set jack, and fine-tune the position of the large and trolley to achieve the accurate placement of the beam.
5. Review the beam position again. After confirming that it is correct, contact the spreader, and the gantry crane can carry out the transfer operation of the next beam. At the same time, it is grouted, and after the grouting strength meets the design strength requirements, the relevant facilities are dismantled, so as to complete the entire beam erection process.

Conclusion

Based on the functional role of the gantry crane itself, in the process of subway construction, the gantry crane has a relatively wide range of applicable space, and will play a vital role in the subway construction process including shield construction. The progress and improvement of construction efficiency are of positive significance. As more and more cities in my country begin the construction of subway projects, this provides a broader development space for the application of gantry cranes. Relying on the good lifting performance and operating space of gantry cranes, it can effectively improve the traditional subway construction process. Facing the equipment lifting problem, in order to build a more efficient and safe subway construction environment.

The role of gantry cranes in the construction of subway projects