As an important transportation corridor of the country, the construction quality, cost control, and construction period arrangement during the construction of expressways have attracted great attention from the society and industry departments. In combination with the wide application of pre - stressed concrete prefabricated T - beams in expressway construction, the following will focus on the use of prefabricated pre - stressed concrete T - beams in expressway construction, analyze the key points of engineering scheme design. Through scientific layout and planning of the beam yard, the balanced development of the contract period and the beam yard construction can be ensured, the application efficiency of construction land can be improved, the management level of the beam yard can be enhanced, and the smooth operation of construction operations can be guaranteed.

1. Design Principles of Prefabricated Beam Yard

The layout of the prefabricated beam yard needs to consider various factors. If not fully considered, it will affect the subsequent work. During the design stage of the prefabricated beam yard, staff need to consider the following aspects:

1.1 Construction Progress of the Project

T - beam prefabrication and erection are very important construction processes in bridge engineering. During the construction period, it is necessary to reasonably master the requirements of the construction period, project characteristics, site conditions, and transportation conditions of finished beams. On this basis, the construction plan for T - beam production and erection should be prepared, and the production capacity of the beam yard can be improved through scientific arrangement.

1.2 Construction Investment Cost

The design of the prefabricated beam yard should start from the construction level, and at the same time, it is necessary to reduce the project construction cost as much as possible without affecting the construction progress. The main factors affecting the construction cost of the prefabricated beam yard are the construction of the prefabricated beam yard site, the transportation of construction raw materials, the transportation of concrete for pouring, and the transportation of finished beams.

1.3 On - site Transportation Distance

For the on - site layout of the prefabricated beam yard, the reinforcement processing area, beam - making area, beam - storing area, office and living area, etc. should be reasonably divided. At the same time, the convenience of material distribution and the rationality of the beam - out passage setting should be considered. Ensuring that each partition can operate independently and minimizing the mutual influence between partition operations are the basic guarantees for the normal production of prefabricated beams.

1.4 Safety Factors

The prefabricated beam yard should reasonably plan the positions of each partition to minimize the influence of processes between partition operations. The track foundation and pedestal foundation of lifting equipment must be checked for bearing capacity. Electrical and water circuits should be placed around the site as much as possible, and on - site equipment can be planned with embedded conduit pipes to ensure that the layout of electrical lines is safe, neat, and orderly.

1.5 Spatial Factors

During the construction process of the prefabricated site, it is necessary to rationally use the space within the site according to the work requirements. Therefore, while reasonably completing the site layout, it is necessary to shorten the construction flow between various processes through refined management to increase the output of prefabricated beams. Plan the optimal beam - transporting route and complete the construction of sub - structures in a timely manner to provide guarantee for the erection of prefabricated beams.

2. Standardized Construction of Construction

2.1 Reinforcement Processing and Installation

For the finished reinforcement of prefabricated box - girder slabs, CNC bending machinery is usually used, and the forming method is adopted. During the reinforcement processing period of prefabricated box - girder finished products, technicians need to clarify the reinforcement size, cutting length, and reinforcement specification during construction according to the drawings. After mastering a sufficient number of parameters, measure the pre - stressed semi - finished products. When it is found that the size of the semi - finished products meets the production standards of the product, the reinforcement can be mass - produced. 

2.2 Processing Templates

The prefabricated box - girder formwork should be determined according to the size of the design drawing, and a factory with construction qualification certified by the state should be selected to follow up the formwork project. After the formwork is transported to the construction site, it is necessary to conduct verification in combination with the installation size of the formwork, complete the measurement and acceptance of the size, and observe whether there are bumps, wear, etc. on the formwork shape during the measurement process. After confirming that there are no quality problems with the formwork, the formwork can be stored in the warehouse for later formwork assembly. During the stage of assembling the outer formwork, rust prevention and grinding treatment of the formwork must be completed before the outer formwork is assembled to ensure that the formwork joints are tight. At the same time, rubber gaskets should be placed between the formwork and the formwork to prevent the problem of corner breakage of the diaphragm during the formwork removal process, so as to smoothly complete the partial removal operation. When bolting the outer formwork plates, triangular pads should also be used for adjustment and support.

2.3 Pouring Concrete

During the concrete pouring stage, it is necessary to understand the operation situation of the concrete after being mixed uniformly at the mixing station. A crane should be selected for prefabricated beam pouring. After pouring, the equipment components should be inspected, and the corresponding work information should be recorded. When pouring concrete, the position of the reserved holes should be determined to ensure that the side formwork and point formwork are closely attached. On this premise, it should be considered whether the axis of the prestressed hole at the end is vertical and whether the end formwork is firmly fixed. Complete the inspection work before concrete pouring to ensure that the materials and equipment used in the construction have met the construction requirements. During the pouring of pre - stressed concrete, the pouring sequence should be clearly defined. First, pour and vibrate the enlarged part at the bottom of the web, then pour the upper web, and finally pour the roof. Conduct construction operations according to the pouring sequence. At the same time, the roof should be poured from both sides to the middle at one time. It must be determined that the pouring method and process plan are the same. During the concrete pouring period, a concrete pouring platform should also be constructed to prevent problems such as reinforcement deformation during pouring.

2.4 Prestressed Steel Strand

During the prestressed steel strand stage, the steel strand should be loaded after passing the quality inspection. The location of the steel strand cutting should be understood, and the site should be fixed. In the place where the steel strand is cut, there should be no water on the ground. Wooden pads should be placed under the lower layer of the steel strand. When the steel strand reel is placed on the reinforcement skeleton, the steel strand laying method should be flexibly selected according to the cutting situation and the curve of the bend. The prestressed steel strand operation method should be determined according to the length reserved in the design document, and the cutting work should be completed with a grinding wheel cutter. In this project, gas cutting and arc methods should not be used. At the same time, after the steel strand is pulled to a certain length, it should be bound with lead wire to prevent the steel strand from loosening and affecting the construction effect of the pre - stressed prefabrication site. After the overall threading of the steel strand is completed, the overall threading form should also be selected to prevent the problem of kinking during the steel strand threading. During the threading stage, the steel strand should be numbered. After numbering at both ends of the steel strand, use wire to complete the binding work. Control the binding spacing of the steel strand within a reasonable range. It is also necessary to ensure that the steel strand is firmly bound before the overall threading and set a traction head at the front end. After all the above work is completed, the speed of the steel strand threading should also be controlled at the end.

2.5 Intelligent Tensioning

Intelligent technology is frequently used during the tensioning stage of steel strands. This is because the use of intelligent tensioning can improve work efficiency, accurately control the prestress value, and at the same time ensure that the elongation of the steel strand during tensioning can reach the design value. When performing intelligent tensioning work, the elongation and tension of the steel strand need to be controlled. It is also necessary to consider the elongation, stress loss, etc. of the intelligent tensioning system during the tensioning stage. Based on the mastered situation, a linear equation graph should be drawn for comparing various engineering data to confirm the tensioning situation. Through the control of various parameters, the working parameters of tensioning are accurately controlled to ensure that the tensioning work can be carried out according to the design standard. During the construction stage of the highway prefabricated beam yard, the intelligent grouting system can largely ensure that the grouting work is carried out according to the specified process. The intelligent grouting system includes a water storage tank, a low - end mixing barrel, an operation interface, a high - speed mixing barrel, a main control box, and other devices. The intelligent grouting work is completed according to the theoretical slurry mix ratio. During the intelligent grouting stage, the on - site construction mix ratio of materials should also be considered, and relevant data should be introduced into the intelligent grouting system to control the grouting consistency. At the same time, the pressure should be controlled within a reasonable range. In addition, after the grouting work is completed, relevant work data should be recorded, and cyclic construction should be carried out according to the workload requirements. Before the T - beam prefabrication, the design drawing must be carefully studied. This is the preparatory work that must be carried out before the template customization work. Construction personnel need to understand the design intention, select the T - beam type from various factors such as technology and construction environment, determine the structural size of the prefabricated beam, and the width, length, flange plate thickness, height, and diaphragm thickness are all structural parameters that construction personnel need to pay attention to. In addition, it is necessary to ensure that the prefabrication direction of each T - beam is the same as the erection direction of the T - beam bridge.

3. Conclusion

The prefabricated beam yard is a temporary construction facility during the expressway construction stage. In order to ensure the smooth progress of the project operation, it is necessary to ensure that the prefabricated beam yard can meet the functional needs of construction personnel for the project operation. During the construction of the prefabricated beam yard, it is necessary to master the content of foundation treatment, the condition of the engineering structure site road. On the other hand, after the construction is completed, land re - cultivation work needs to be carried out, the construction period should be determined, and the follow - up work related to the prefabricated beam yard should be completed. All resources should be reasonably used, so that while achieving the purpose of the project operation, the total cost of project construction can also be reduced.