Prefabricated Beam and Slab Construction

The construction of prefabricated beams and slabs for buildings should follow the following key steps and technical points:

1. Drawing Review and Plan Preparation Before construction, the technical department should be organized to review the design drawings, focusing on confirming the geometric dimensions of components (cross-sectional error ≤ ±5mm), the positional deviation of embedded parts (≤ 10mm), and the reinforcement configuration (main reinforcement cover thickness of 25mm). BIM technology should be used to establish a three-dimensional model, simulate the installation process, and optimize the construction sequence. The specialized construction plan should cover aspects such as formwork, reinforcement, concrete, transportation, and lifting, and be implemented after approval by the supervisor. Technical disclosures should clarify key control points, such as the prestress tensioning sequence (symmetrical tensioning at both ends) and the setting of lifting points (1.2m from the beam end).

2. Material and Equipment Requirements

• Materials: Reinforcement should use HRB400E (Φ12-25mm, yield strength ≥ 400MPa), prestressed steel strands should be Φs15.2 (tensile strength 1860MPa), concrete strength grades should be C40/C35 (28d compressive strength ≥ 40MPa/35MPa), formwork should be 15mm thick multi-layer boards (elastic modulus ≥ 4500MPa), and embedded parts should use Q235B steel plates (galvanized layer ≥ 85μm).
• Equipment: The prefabrication yard should be equipped with a 120t hydraulic tensioning jack (calibration validity period of 1 year), a JS500 concrete mixer (mixing time ≥ 90s), and on-site installation should use a 25t truck crane (rated lifting capacity of 8.5t when the main boom is 18m) and an ultrasonic flaw detector (sensitivity ≥ 2dB).

3. Site and Formwork Design

• Prefabrication Site: Hardening treatment should use 200mm thick C25 concrete + bidirectional Φ12@200 reinforcement mesh, with a surface flatness deviation ≤ 3mm/2m, a 5‰ drainage slope, and drainage ditches. Areas for reinforcement processing, formwork stacking, and concrete curing should be designated.
• Stacking Site: Support piers should be spaced 2.5m apart, with a stacking height of ≤ 3 layers, and 100mm × 100mm square timbers should be placed between layers. The support points should be consistent with the lifting points.
• Formwork Design: Side formwork should use 6mm thick Q235 steel plates, core formwork should use inflatable capsules (diameter 550mm), and be fixed with M20 tie rods (spacing 600mm).

4. Construction Process and Technological Innovation The production of prefabricated beams covers standardized processes such as formwork assembly, reinforcement binding, and concrete pouring and curing, and should comply with the "Construction Process Regulations for Building Engineering". Modern technologies such as intelligent circular production lines, digital twin technology, and steam curing processes have been introduced to achieve full-process automation. In terms of green technology, microalgae carbon fixation technology can realize waste gas resource utilization, and the combination of lightweight ultra-high-performance concrete (LUHPC) and ultra-high-performance concrete (UHPC) structures enhances mechanical properties and durability.

5. Industry Standards and Sustainable Development Construction should comply with norms such as the "Technical Standard for Prestressed Prefabricated Concrete Frame Structures" (JGJ/T502-2024). The recycling of prefabricated beams is technically and economically feasible, and the application of high-performance materials promotes the lightweight and low-carbon development of structures.