With the vigorous development of the transportation industry, the number of highway bridge projects under construction is gradually increasing. The construction method of cast-in-place beam support, as an important construction technology for highway bridges, has numerous advantages. This article explores the construction method of cast-in-place beam support.

1. Foundation Treatment

In the construction process of cast-in-place beam support, foundation treatment is a crucial link. Because the stability of the foundation is directly related to the quality of the entire highway bridge project. In practice, the foundation treatment mainly includes three aspects: ① Treat the foundation, and backfill the bearing platform foundation pit and the mud pit; ② Conduct overall foundation treatment; ③ Do a good job in drainage treatment.

2. Scaffolding Erection

2.1 Selection of the Support

When using the construction method of cast-in-place beam support, the most suitable support should be selected according to the actual situation of the highway bridge project.

2.2 Scaffolding Erection

To ensure the construction quality, the support used during the construction must have a stable structural system, good bearing capacity, stiffness, and overall stability. Before erecting the support, it is usually necessary to have an in-depth understanding of the actual situation of the highway bridge construction project, master the construction conditions, and formulate a special construction plan that meets the requirements. Moreover, it is also necessary to carry out the stress checking calculation. With safety as the prerequisite, pay attention to cost savings and complete the construction project efficiently. On the premise of safe construction, save costs and complete the project with high efficiency. During the process of erecting the support, it is usually necessary to ensure that the foundation is reinforced to meet the stress requirements. Also, ensure that the materials of the support meet the requirements, and that the connections between the various members are firm and reliable.

 2.3 Preloading of the Support

This is to test the strength of the support and the foundation, and detect the actual bending resistance and stability of the support.

3. Formwork Construction

Before carrying out the formwork construction, it is usually necessary to collect the preloading data of the support in advance, analyze and calculate the collected data. On the basis of considering the influence of tensioning, accurately calculate the camber value. Then, control the elevation of the bottom formwork according to the designed elevation of the beam bottom and the camber value. To ensure the construction quality, it is usually necessary to select high-quality bamboo plywood as the formwork, and fix it with wooden planks and section steel. After that, assemble the outer formwork. During the assembly process, it is necessary to strictly control the elevation, angle, and flatness of the formwork.

4. Steel Bar Construction

Steel bar construction is a very important link in the construction process of cast-in-place beam support. When erecting the steel bar framework, it is also necessary to strictly control the positioning steel bars, and carry out the construction strictly in accordance with the relevant requirements and the construction plan to ensure that there is an appropriate distance between the corrugated pipes and embedded parts and the non-prestressed steel bars. Then, start from the mid-span, and erect and bind the non-prestressed steel bars every 40 cm towards both ends. When installing the anchor backing plate, a spiral reinforcement should be sleeved on the outer side of the corrugated pipe, and the anchor backing plate should be installed strictly according to the designed elevation.

5. Concrete Pouring

In the concrete pouring link, it is usually necessary to first centrally mix the concrete in the mixing plant, and then transport the concrete to the site for construction by a special tank truck. In this link, first of all, it is necessary to strictly control the mix proportion of the concrete to ensure that it meets the relevant requirements. Moreover, when controlling the slump of the concrete, the transportation loss value should also be fully considered. In addition, during the specific pouring process, the stability of the support must be fully considered. During the pouring, 2 or more truck-mounted pumps can be used simultaneously for pouring. At the web plate, it is necessary to carry out layered pouring, and strictly control the thickness of each pouring layer, keeping it below 40 cm. Also, when pouring a new layer, it must be before the previous layer sets. After the concrete pouring is completed, curing should be carried out to keep the surface sufficiently moist. Generally speaking, in this construction technology, the curing time of the concrete usually needs to be controlled for more than 14 days. The relevant staff should monitor various indicators of the concrete surface every day, especially the temperature and humidity, and record the data of each day. Once any abnormal phenomenon is found, measures should be taken immediately for treatment.

Conclusion

The construction quality of highway bridges not only directly affects the subsequent use effect but also affects social stability. Therefore, in order to improve the construction quality of highway bridges to a greater extent, construction units have begun to introduce the construction technology of cast-in-place beam support. Moreover, in order to ensure the construction quality, it is necessary to strictly control each construction link.