4.7 Prefabricated Prestressed Concrete Component Technology for Prefabricated Houses
4.7.1 Technical Overview
Prefabricated prestressed concrete components are factory-produced horizontal and vertical elements made using pretensioning technology. These components primarily include prestressed hollow slabs, double T-slabs, beams, and wall panels. Various horizontal prefabricated prestressed elements can be assembled to form integral floor slabs. Hollow slabs and double T-slabs may either exclude a cast-in-place concrete topping or include one, depending on functional and structural requirements. Prefabricated prestressed beams can be designed as composite or non-composite, while wall panels are suitable for a wide range of public and industrial buildings.
The key advantage of these components lies in the use of high-strength prestressed steel wires and strands. This reduces the required amount of steel reinforcement and concrete while allowing for a thinner floor structure. During construction, these elements typically require no temporary supports, which significantly lowers formwork costs and brings notable economic benefits. Floors constructed with prefabricated prestressed components offer high load-bearing capacity, excellent structural integrity, and enhanced crack resistance. These advantages align with green construction principles, such as the “Four Sections and One Environmental Protection” standards, and support the modernization of building industrialization. Additionally, prestressing technology enables the production of longer wall panels, facilitating multi-story applications.
4.7.2 Technical Specifications
(1) Prestressed concrete hollow slabs are typically 1.2 meters wide, with other widths including 0.6 and 0.9 meters. Standard slab thicknesses range from 100mm up to 380mm (e.g., 100, 120, 150, 180, 200, 250, 300, 380 mm). Depending on the cross-section height, slab spans can vary between 3 and 18 meters.
(2) Prestressed concrete double T-slabs are available in two types: slope slabs and flat slabs. Slope slabs generally have widths of 2.4 or 3.0 meters, with typical spans of 9, 12, 15, 18, 21, or 24 meters. Flat slabs come in widths of 2.0, 2.4, or 3.0 meters, with similar span ranges.
(3) The span of prestressed concrete beams depends on project requirements, commonly ranging between 6, 7.5, and 9 meters for industrial buildings.
(4) Prestressed concrete wall panels usually have fixed widths of 1.5, 2.0, or 3.0 meters. Their lengths are determined by column spacing or floor height.
For specific project needs, non-standard spans and widths can be accommodated through custom design.
The production, installation, and construction of prefabricated prestressed concrete slabs must comply with national standards, including the “Code for Design of Concrete Structures” (GB50010), “Code for Acceptance of Construction Quality of Concrete Structures” (GB50204), and “Technical Specification for Prefabricated Concrete Structures” (JGJ 1). Design and application can follow standardized drawings such as 03SG435-1~2 for prestressed concrete hollow slabs, 05SG408 for SP prestressed hollow slabs, 06SG432-1, 09SG432-2, and 08SG432-3 for double T-slabs, and 13G440 for large-span prestressed hollow slabs (spanning 4.2m to 18.0m). Prefabricated components can be selected directly or custom-designed based on project requirements.
4.7.3 Scope of Application
This technology is widely applicable to various industrial and residential buildings. Prestressed hollow slabs are used for floors and exterior wall cladding in both concrete and steel structures. Prestressed double T-slabs primarily serve as floor slabs and roofs in public and industrial buildings, with slope slabs reserved exclusively for roofing.
For floor slabs spanning less than 9 meters, composite slabs made from prestressed hollow slabs (SP slabs) with a cast-in-place topping are common. For heavier loads within 9 meters or spans exceeding 9 meters, composite slabs using prestressed double T-slabs with cast-in-place toppings are preferred. Prefabricated prestressed beams come in various cross-sectional shapes—including rectangular, flower basket, L-shaped, and inverted T-shaped—facilitating easy integration with double T-slabs and hollow slabs.
4.7.4 Engineering Examples
The factory building at Qingdao Dingxin Communication Technology Industrial Park utilizes heavy-duty double T-slab composite floors. The training building at Leshan No.1 Vocational High School employs prefabricated prestressed hollow slab flooring.
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