Installation of Prefabricated Beam Components for Houses
The installation of prefabricated beam components for houses should follow scientific and standardized procedures and key points, as detailed below:
1. Planning of Hoisting Sequence
The installation of prefabricated beams should adhere to the principle of 'main beams first, secondary beams later, and lower beams before upper beams'. Main beams, as the primary load-bearing components of the structure, should be installed first to form a stable framework. Secondary beams should be installed after the main beams are positioned to avoid affecting the accuracy of the secondary beams due to displacement of the main beams. In terms of height, hoisting of upper-level beams should only commence after the installation of lower-level beams is complete to prevent the accumulation of risks associated with high-altitude operations and ensure the overall stability of the structure.
2. Post-Hoisting Treatment of Composite Slabs
After the hoisting of composite slabs is complete, the height difference and width of the joints at the bottom of the slabs should be immediately checked. If the height difference exceeds the design allowance (usually ≤3mm), the slabs should be re-hoisted and adjusted to the compliant value using adjustable supports. Adjustable supports enable fine adjustments through a screw-based lifting mechanism to ensure that the flatness of the composite slabs is consistent with the top surface of the prefabricated beams, preventing floor cracking or hollowing in the later stages. The width check should ensure uniform joints to prevent concrete leakage during pouring due to excessively large gaps.
3. Conditions for Removal of Temporary Supports
The removal of temporary supports should strictly adhere to the strength indicators of the post-poured concrete. The design documents will specify the strength requirements (such as reaching 75% or 100% of the design strength), which should be confirmed through testing of test blocks cured under the same conditions. Premature removal may lead to structural deformation or collapse, while delayed removal may affect the construction progress. Before removal, the stability of the support system should be checked, and the principle of 'symmetry and batch removal' should be followed to avoid local stress concentration.
4. Core Points of Hoisting Technology
- Hoisting Method: When using a tower crane for hoisting, a steel spreader should be used as an auxiliary tool to prevent component deformation by distributing the load at multiple points. The hoisting points should be pre-embedded or marked according to the design drawings to ensure that the components are hoisted horizontally and avoid tilting and bumping the corners.
- Movement and Positioning: After the components are hoisted steadily, the crane arm should be moved at a constant speed. As the components approach the building, manual assistance should be provided for centering, and the position should be fine-tuned using crowbars or chain blocks to ensure that the beam ends accurately fall into the reserved slots of the supports.
- Special Requirements for Exterior Wall Components: The hoisting points and support members of prefabricated concrete exterior wall components should be pre-embedded in advance, with the pre-embedding position deviation controlled within ±5mm to ensure hoisting safety and connection accuracy.
5. Relevance of Installation Process
The installation of prefabricated beams is a critical node in the construction of prefabricated buildings: it should be carried out after the completion of the post-poured sections of shear walls, beam formwork erection, floor slab erection, and prefabricated beam scaffolding erection. After hoisting is complete, the installation of composite slabs can proceed, followed by subsequent processes such as reinforcement binding and concrete pouring for beams and slabs within the floor. All processes are closely linked, and smooth progression should be ensured through construction scheduling and on-site coordination.
