How to Prefabricate T-shaped Beams in Houses

The prefabrication of T-shaped beams (T-beams) in houses should follow standardized procedures, with specific steps as follows:

1. Construction Preparation

Complete the assembly of the mobile pedestal to ensure its stability. Connect to the power supply and convert it to a safe voltage, for example, converting 380-volt alternating current to 36-volt direct current through a step-down cabinet to ensure construction safety. At the same time, check the status of equipment such as formwork and vibrators to ensure that the conditions for concrete pouring are met.

2. Installation of Reinforcement Cage

Use a gantry crane to lift the pre-tied T-beam reinforcement cage. Fix the negative moment tooth plates and top plate reinforcement using the reinforcement jig method to ensure that the reinforcement spacing and protective layer thickness meet the design requirements. After the entire cage is lifted into the formwork, check again for any displacement of the cage.

3. Installation of Prestressed Ducts

Insert prestressed core-pulling pipes into the reinforcement cage and protect them with steel corrugated pipes to prevent duct deformation or grout leakage. The duct positioning must be accurate, and the bending radius must meet the specifications to avoid excessive friction loss during subsequent tensioning.

4. Concrete Pouring and Formwork Removal

Pour concrete in layers and vibrate it densely using an immersion vibrator to avoid defects such as honeycombs and pits. Remove the formwork when the concrete strength reaches more than 75% of the design value to prevent beam deformation due to insufficient strength.

5. Prestressed Tensioning and Grouting

• Grouting immediately after tensioning: After each T-beam is tensioned, grouting and anchor sealing should be completed within 24 hours to reduce prestress loss.
• Duct cleaning: Before grouting, rinse the duct with clean water and then remove the accumulated water with high-pressure air to ensure duct patency.
• Grouting operation: Start from the lowest point of the beam, use a piston-type grouting pump to continuously grout at a pressure of 0.5-0.7 Mpa, and exhaust air through the exhaust vent at the highest point until thick grout emerges from the other end. Maintain the pressure for 2 minutes and then seal the grouting hole. Priority should be given to vacuum grouting technology. First, grout the lower duct, and the interval between two grouting operations should be 30-45 minutes.

6. Anchor Sealing

After grouting, clean the area around the anchorages, set up a reinforcement mesh, and pour anchor-sealing concrete with a strength consistent with that of the T-beam body. Strictly control the length of the beam after anchor sealing to avoid installation problems caused by dimensional deviations.

7. Beam Inspection and Transportation

The construction unit should request the supervising engineer to inspect the beam length, strength, cross-sectional dimensions, and appearance quality (such as exposed reinforcement and pits) and form a record. Only after the grouting strength meets the standard can the beam be transported and lifted.

8. Curing and Flow Production

Lift the prefabricated T-beams to the beam storage area and perform spray curing to keep the surface moist. Subsequent T-beam prefabrication should follow this process in a cycle to form efficient flow production.