Illustration of Beams in Prefabricated Houses

The beams in prefabricated houses mainly include prefabricated solid beams, prefabricated composite beams, prefabricated U-shaped beams, and prefabricated prestressed beams. Although there are no specific illustrations, their structural characteristics and application scenarios can be described in text.

Prefabricated Solid Beams

Prefabricated solid beams are cast in one piece using steel reinforcement and concrete. The internal steel reinforcement framework provides tensile strength, while the concrete bears the compressive forces, forming a stable load-bearing structure. Their cross-sections are typically rectangular, with dimensions designed according to span and load requirements. Their core advantages lie in their simple structure and strong load-bearing capacity, making them suitable for scenarios with smaller spans (e.g., 3-6 meters) or high load demands, such as lintel beams over door and window openings and roof load-bearing beams in low-rise buildings. In rural self-built houses, prefabricated solid beams are often preferred due to their convenient construction and high safety.

Prefabricated Composite Beams

Prefabricated composite beams consist of two parts: a factory-prefabricated concrete beam at the bottom and a cast-in-place concrete layer at the top. The prefabricated part usually has steel reinforcement protruding, which connects with the cast-in-place layer through steel reinforcement to form an integral structure. Their design is highly flexible, allowing them to accommodate the need for embedded pipes or holes in the floor slab, avoiding structural damage from later slotting. For example, in areas such as bathrooms and kitchens that require the laying of water and electricity pipelines, composite beams can adjust the thickness of the prefabricated part and the cast-in-place layer to reserve space for pipelines while ensuring structural strength.

Prefabricated U-Shaped Beams

Prefabricated U-shaped beams have a cross-section in the shape of an upside-down 'U'. The interior can be filled with concrete or used directly as a hollow structure. Their characteristics include light weight and good torsional resistance, making them suitable for scenarios that require a reduction in structural weight or the ability to withstand torsional forces, such as bridge beams and roof beams in large factories. In prefabricated buildings, U-shaped beams can form an efficient load transfer path in combination with prefabricated floor slabs and wall panels, enhancing overall stability.

Prefabricated Prestressed Beams

Prefabricated prestressed beams use prestressing techniques (such as pretensioning or post-tensioning) to apply compressive stress in the concrete in advance, counteracting the tensile stress during use and significantly improving load-bearing capacity. Their core advantages include reduced cross-sectional dimensions, steel savings, and extended spans (up to 12-18 meters). For example, in multi-story residential or commercial buildings, prestressed beams can reduce the number of columns, increasing the flexibility of interior space. Additionally, prestressing techniques can reduce the risk of concrete cracking and extend the structural lifespan.

Summary of Application Scenarios and Advantages

Prefabricated beams are widely used in positions such as lintel beams over doors and windows, roof load-bearing beams, and floor slab supports in prefabricated buildings, working in conjunction with prefabricated floor slabs, wall panels, and other components to form a complete structural system. Their advantages include:

• High safety: Factory-standardized production ensures controllable quality and certification by national standards;
• Efficient construction: Direct installation reduces the time for on-site formwork support and concrete pouring;
• Good economy: Mass production reduces costs, and material utilization is higher than on-site fabrication.

For an intuitive understanding of the structure and connection methods of prefabricated beams, it is recommended to refer to the 'Technical Specification for Prefabricated Concrete Structures' or professional architectural engineering drawings, which contain detailed node details and construction instructions.