Prefabricated Floor Slab Assembly in Housing

Prefabricated floor slabs for housing are industrialized building components that are pre-fabricated in a prefabrication yard or factory and transported to the construction site for installation. The following provides an introduction from the perspectives of specifications, installation, advantages and disadvantages, and application cases:

Specification Design: Standardized specifications are adopted, with lengths typically being multiples of 300mm, widths multiples of 100mm, and thicknesses ranging from 120-300mm. Common types include flat slabs, channel slabs, and hollow slabs. Among them, hollow slabs are widely used due to their light weight and cost-effectiveness, while channel slabs adapt to different support requirements through their positive and negative structures. Prestressed technology can save 30%-50% of steel and 10%-30% of concrete, improving crack resistance. For example, the YKB3606-8a prestressed concrete floor slab is 3.6 meters long, 0.6 meters wide, and 120 millimeters thick, with 8 main reinforcement bars. Traditional prefabricated hollow slabs have a maximum standard span of 4.2 meters, with widths mostly being 500mm and 600mm, and common thicknesses of 120mm and 150mm.

Installation Process: Taking prefabricated concrete floor slabs as an example, before installation, holes in the floor slabs need to be sealed. After bending the reinforcement bars, the hard-frame formwork method is used to directly install the floor slabs on the formwork. After calibrating the dimensions, concrete is poured. After hoisting the floor slabs, the reinforcement bars need to be bent downward at a 45-degree angle and crossed, and full-length reinforcement bars should be added. The support distance from the wall is generally 8 centimeters, and a slab band should be added when encountering structural columns. The treatment of slab joints should meet the requirements of 2 centimeters at the bottom and 4 centimeters at the top, and concrete should be poured after the main construction is completed. The installation of prefabricated reinforced concrete floor slabs should meet the support lengths (wall ≥ 90mm, beam ≥ 60mm). Slab joints should be filled with fine aggregate concrete or reinforced with steel mesh according to their width, and the overall integrity should be enhanced through anchor reinforcement bars.

Advantages and Disadvantages:

• Advantages: Short construction period, stable quality, high material utilization rate, suitable for rural areas with inconvenient transportation, simple maintenance, and low cost.
• Disadvantages: Poor integrity, prone to displacement and slippage during earthquakes or foundation settlement; limited earthquake resistance, prone to water leakage and cracking; uneven process quality, with reinforcement costs possibly exceeding those of cast-in-place slabs; improper treatment of slab joints can easily lead to water seepage, especially in areas such as kitchens and bathrooms.

Application Cases: These include projects such as the Oodi Central Library and Tripla Comprehensive Commercial Center in Helsinki, Finland; the V&A Waterfront Demountable Parking Garage in Cape Town, South Africa; the IKEA store in Batu Kawan, Malaysia; and the DNB Bank headquarters in Oslo, Norway.