Prefabricated Floor Slab Construction

The construction of prefabricated floor slabs in buildings should follow the following steps and key points:

1. Types and Selection of Prefabricated Slabs

Commonly used prefabricated reinforced concrete slabs are classified into flat slabs, channel slabs, and hollow slabs based on their cross-sectional forms. Hollow slabs, due to their light weight and good economy, are the most widely used floor slab components, especially suitable for multi-story residential buildings and other structures sensitive to self-weight. Selection should be based on a comprehensive assessment of load requirements, span, and economy.

2. Construction Preparation and Lifting

For lifting composite slabs, it is recommended to use lifting steel beams to ensure that the lifting points bear force synchronously and prevent cracks or distortions in the components due to uneven force. Before lifting, check the firmness of the connection between the lifting device and the prefabricated slab. Maintain stability during the lifting process and strictly prohibit oblique pulling and hard dragging to prevent damage to the components.

3. Installation and Support

1. Support Length Requirements: The support length on walls should not be less than 90mm, and the support length on beams should not be less than 60mm to ensure effective transfer of loads to the supporting structure.
2. Layout Methods: Optimize the layout based on the space size and slab specifications, prioritizing economical and reasonable plans. Flat layout involves directly placing prefabricated slabs on walls, suitable for small-span spaces; beam-slab layout involves supporting the floor slab on beams, which are then placed on walls, suitable for large-span or high-load areas.

4. Slab Joint Treatment

1. Joint Type Selection: Side joint forms include V-shaped, U-shaped (single-tooth), and groove-shaped (double-tooth). Double-tooth joints can significantly enhance the overall stiffness of the floor slab and are recommended for use in areas with poor foundation conditions or earthquake-prone regions.
2. Joint Width Treatment:
   • Joint width < 30mm: Fill with fine aggregate concrete;
   • Joint width > 50mm: Add steel mesh in the joint and then fill with fine aggregate concrete;
   • Joint width = 120mm: Leave the joint near the wall and fill with bricks picked along the wall;
   • Joint width > 120mm: Treat with a reinforced concrete strip cast in situ using a steel frame.

5. Integrity and Anchoring

Anchor bars should be set at the connections between slabs and walls, and at the ends of slabs. Especially in areas with poor foundation conditions or earthquake-prone regions, anchoring measures can significantly enhance the overall stiffness and seismic performance of the floor slab. The specifications and spacing of anchor bars should comply with design specifications to ensure reliable connections.

6. Construction Precautions

It is strictly prohibited to ignore key structural measures for cost savings, such as the installation of ring beams. Ring beams can enhance the overall integrity of the building and effectively resist horizontal loads such as earthquakes, serving as an important structure to ensure seismic performance. Construction should be carried out strictly in accordance with design requirements to avoid safety hazards caused by structural defects.