Construction Process of Prefabricated Panel Houses

The construction process of prefabricated panel houses mainly consists of two major stages: the manufacturing and installation of prefabricated panels. The specific steps are as follows:

Manufacturing Process of Prefabricated Panels

1. Mold Preparation
   Workers form a mold by surrounding steel plates and secure the shape by tightening screws. They then spray a mold release agent on the inner walls of the mold. The purpose of this step is to prevent the subsequently poured concrete from adhering to the mold, ensuring that the prefabricated panel has a smooth surface when removed from the mold and that the mold can be reused.

2. Laying of Steel Reinforcement Framework

   • First Layer of Steel Reinforcement Framework: The distribution bars (the first layer of steel reinforcement framework), which fit precisely with the mold, are placed into the mold from above, serving as the basic load-bearing structure of the prefabricated panel.
   • Insertion of Foam Boards: A thin layer of concrete about 4 centimeters thick is poured onto the first layer of steel reinforcement framework, followed by the placement of a large foam board with a thickness of 15 centimeters. The foam board occupies half of the volume of the prefabricated panel and is fixed in position with iron hooks. Its function is to reduce the weight of the prefabricated panel and form a hollow structure (if it is a hollow panel).
   • Second Layer of Steel Reinforcement Framework: A second layer of steel reinforcement framework is laid on the foam board, and dozens of high-tensile-strength steel strands (load-bearing bars) are threaded through to enhance the overall load-bearing capacity of the prefabricated panel.

3. Steel Strand Tensioning and Concrete Pouring
   Using the "pre-tensioning" method, specialized equipment is used to stretch the steel strands to their ultimate strength, and then the second layer of concrete is immediately poured. During the pouring process, a vibrating rod is used to vibrate the concrete to expel internal air bubbles, preventing cracking or honeycombing after hardening.

4. Curing and Shaping
   The prefabricated panels are sent to a basement for 4 hours of steam curing, accelerating the hardening of the concrete through a high-temperature and high-humidity environment. After curing, the steel strands are released, the prefabricated panels are lifted with a gantry crane, and the excess steel bars are cut off to complete the final shaping.

Installation Process of Prefabricated Panel Houses

1. Component Transportation
   The concrete components (such as prefabricated panels, beams, and columns) prefabricated in the factory are transported to the construction site by specialized vehicles. During transportation, the components need to be fixed to prevent damage.

2. On-site Assembly
   According to the design drawings, the prefabricated panels are directly lifted to the designated positions and connected by welding or bolts to form structures such as floor slabs and roof insulation layers. For hollow prefabricated panels, attention should be paid to the sealing treatment at the joints to prevent rain leakage or a decrease in sound insulation performance.

Other Key Information

• Type Differences: Prefabricated panels are divided into solid and hollow types. The hollow structure achieves lightweighting by reducing the non-load-bearing concrete, making it suitable for building scenarios sensitive to weight.
• History and Limitations: Prefabricated panel houses originated in the early 20th century. In China, most residential buildings constructed before 1985 adopted this type of structure. However, they have problems such as weak earthquake resistance, poor sound and heat insulation, and a service life of about 30-50 years, requiring regular inspection or renovation.