Old-Style House Prefabricated Slab Structure Diagram

Although there is no specific diagram for the prefabricated slab structure of old-style houses, the placement direction of the slabs should adhere to the following core principles to ensure structural safety, construction convenience, and compliance with regulatory requirements:

1. Prioritize Structural Load-Bearing and Regulatory Constraints In frame structures, prefabricated slabs should preferably not be long-span slabs (i.e., the long side of the slab is parallel to the frame beams), as differences in structural deformation can easily lead to slab joint cracking. If long-span slabs must be used, the risk can be reduced by reinforcing the reinforcement (e.g., adding bidirectional reinforcement) or adjusting the slab joint treatment (e.g., adding bidirectional φ6@250 reinforcement when the slab joint width is > 60mm). Pure frame structures generally do not require a monolithic pouring layer, but if the design requires enhancing the overall integrity of the floor, a 50mm thick C20 concrete monolithic pouring layer with bidirectional reinforcement should be provided.

2. Guide by Construction Convenience The slab placement direction should simplify the construction process:

• Place slabs from the interior of the room outward, prioritizing the use of wide slabs to reduce the number of slab joints;
• The cast-in-place slab band (the part requiring on-site concrete pouring) should be arranged near the window, with a width of ≥ 200mm, to reserve space for plumbing risers to pass through the slab;
• Try to unify the slab joint width at 40mm, in which case no reinforcement or only one reinforcement bar may be added to avoid frequent on-site adjustments.

3. Adapt to Building Function and Structural Requirements

• No Prefabricated Slabs at Structural Columns: Structural columns are key nodes of the structure, and prefabricated slabs cannot form an integral connection with them, easily leading to safety hazards;
• No Prefabricated Slabs in Underground Garages: Fire protection regulations require that underground spaces adopt structural forms with better integrity, such as cast-in-place concrete;
• Slab Joint Treatment and Load-Bearing Coordination: The slab ends of prefabricated slabs (such as YKB hollow slabs) need to be capped to bear the load. The slab joint width directly affects the structural performance: < 30mm is unqualified and requires adjustment; 30-50mm is qualified and may not require reinforcement; 50-110mm requires reinforcement treatment; > 110mm and < 500mm requires adding a slab band (by adding a slab or adjusting the layout to meet the requirements).

4. Unify Numbering and Slab Placement Logic Although not directly related to direction, numbering rules affect construction efficiency:

• For rooms of the same type, directly mark the room number and use a unified numbering system throughout the building;
• When marking the number and type of prefabricated slabs, use horizontal or vertical lines to avoid diagonal line intersections that can cause confusion in the drawing.

Key Summary: The placement direction of prefabricated slabs should comprehensively consider structural safety, construction efficiency, and regulatory requirements. High-risk scenarios such as placing long-span slabs parallel to frame beams and placing slabs at structural columns should be avoided as a priority. At the same time, details such as unifying slab joint widths and optimizing numbering logic should be used to improve construction quality.