How to Handle Steel Bars in Prefabricated Slab Houses

The handling of steel bars in prefabricated slab houses requires selecting reinforcement or construction methods based on specific scenarios. Common methods are as follows:

I. Handling of Steel Bars on the Original Slab Surface

If the prefabricated slab has exposed or corroded steel bars, grinding treatment is required first: remove rust, burrs, and concrete debris from the surface of the steel bars to ensure a flat surface; then apply rust protection paint (such as epoxy resin-based) to prevent further corrosion of the steel bars when pouring new concrete. If there are significant differences in steel bar specifications or if the connection strength needs to be enhanced, the steel bar welding process can be adopted: weld the exposed steel bars with newly added steel bars to form an integral whole. After welding, a pull-out test is required to inspect the quality of the joints, and finally, anti-corrosion treatment (such as spraying zinc-based coatings) is applied to the welded parts.

II. Application of Steel Bars in the Reinforcement of Prefabricated Slab Buildings

1. Under-slab reinforcement: Install profile steel supports (such as I-beams and channel steels) along the four corners or the longest side of the prefabricated slab, changing the traditional four-sided support to eight-sided support, significantly improving the load-bearing capacity of the floor slab. The profile steels need to be fixed to the wall with chemical anchors or expansion bolts, with the spacing determined by calculations.
2. Sandwich reinforcement: Adopt the top-and-bottom sandwiching method, laying steel bar mesh (with a diameter of 6-8mm and a spacing of 150-200mm) on the upper and lower surfaces of the floor slab, fixed with through-wall bolts or planted rebars, forming an integral load-bearing structure to enhance the flexural and shear resistance of the floor slab.
3. Connection part reinforcement: Add reinforcement bolts or connecting steel plates at the joints of the prefabricated slabs and the connections between the walls and the floor slab to improve the overall structural integrity; for earthquake-resistant areas, seismic diagonal braces or energy-dissipating dampers need to be added.
4. Roof reinforcement: If the roof is a prefabricated slab structure, reinforced concrete beams or steel bar mesh (double-layer and bidirectional, with a diameter of ≥8mm) can be added, connected to the original structure through planted rebars, improving the load-bearing capacity and waterproof performance of the roof.

III. Construction Standards for Steel Bars in Self-built Prefabricated Slab Houses

1. Steel bar configuration: Adopt a double-layer and bidirectional steel bar mesh (bottom rebars + top rebars), with a steel bar diameter of ≥6mm and a spacing of ≤150mm, which needs to be fully tied and fixed; add 7 radial rebars (with a length of ≥1/4 of the slab span) at the corners of the slab to prevent cracking caused by stress concentration.
2. Pipeline embedding treatment: Lay steel wire mesh (with a mesh size of 50×50mm) at the pipeline embedding locations to avoid concrete shrinkage cracks; pipelines should avoid crossing rebars horizontally. If crossing is necessary, crossing boxes should be used for protection.
3. Cover control: Use 2cm-thick special spacers to ensure the thickness of the steel bar cover, with a spacer spacing of ≤1m, preventing the steel bars from being exposed and causing corrosion.

Precautions: All steel bar handling plans need to undergo structural calculations based on actual engineering conditions. If uncertain, entrust a professional design unit or a third-party testing agency to issue reinforcement drawings, and have them operated by a qualified construction team to ensure structural safety.