Casting High-Rise Prefabricated Slabs for Houses
The common structural forms of prefabricated slabs for high-rise houses are hollow slabs and composite slabs, which differ in construction, performance, and applicable scenarios and need to be selected according to specific needs.
Hollow Slabs: Lightweight and Earthquake-Resistant Prefabricated Components
Hollow slabs are prefabricated prestressed reinforced concrete slabs with internal longitudinal channels as their core structure. This design achieves weight reduction by reducing the amount of concrete used, while prestressing technology enhances the crack resistance and stiffness of the slabs, providing good earthquake resistance in high-rise buildings. Their dimensions are determined based on the room spans (e.g., 3-6 meters) and the lifting capacity of the machinery, with common specifications including spans of 2.4-6 meters and thicknesses of 120-300 millimeters.
During construction, hollow slabs are directly laid on beams or walls through lifting, and channels within can accommodate piping, but care must be taken to avoid damaging the prestressed tendons. Their advantages lie in high industrial production efficiency and fast construction speed, and their lightweight nature reduces foundation loads. However, the integrity of hollow slabs relies on post-pouring strips or cast-in-place layers for connection; improper connection may affect earthquake resistance, making them more suitable for high-rise residential or office buildings with multiple standard floors and regular room spans.
Composite Slabs: Assembly Integrated Structures with Strong Overall Continuity
Composite slabs are formed by combining prefabricated slabs with cast-in-place layers, belonging to the category of assembly integrated slabs. Their prefabricated slabs are typically prestressed thin slabs (60-80 millimeters thick), with their surfaces treated by roller indentation to enhance bonding with the cast-in-place layer; the thickness of the cast-in-place layer is determined based on the span (usually ≥90 millimeters), and it can accommodate piping and be filled with expanded polystyrene boards to form a box-shaped cross-section, further reducing weight and improving sound insulation.
This structure commonly has spans of 4-6 meters, with a maximum of 9 meters, and is suitable for high-rise buildings and large-span buildings (e.g., shopping malls, exhibition halls). Its core advantage lies in strong overall continuity: the prefabricated slabs serve as permanent formwork, forming a common load-bearing system with the cast-in-place layer, avoiding weak points at the connections of hollow slabs; at the same time, the thickness of the cast-in-place layer can be flexibly adjusted to meet different load requirements, and no additional formwork is needed during construction, saving formwork costs and shortening the construction period. However, composite slabs have high precision requirements for prefabricated slabs, and care must be taken during transportation and lifting to prevent thin slab fracture, with construction costs slightly higher than those of hollow slabs.
Selection Advice: Weigh Based on Building Needs
If the building has regular room spans, many floors, and cost control is necessary, hollow slabs are an efficient choice; if large-space flexibility, high overall integrity, or complex piping arrangements are pursued, composite slabs are more advantageous. In actual projects, the two are often used in combination, for example, adopting composite slabs in the core tube area to meet earthquake resistance requirements and hollow slabs in standard floors to improve efficiency.
