Design of Lifting Plan for Prefabricated Houses

The design of the lifting plan for prefabricated houses should cover the design of the lifting frame, material selection, construction preparation, process flow, and safety and quality assurance. The specific plan is as follows:

I. Lifting Frame Design

1. Design Basis: Follow the "Design Code for Hoisting Machinery" (GB/T3811-2008) and the "Standard for Design of Steel Structures" (GB50017-2017), combined with the weight, dimensions, lifting conditions, and on-site environment of the prefabricated house for comprehensive design.
2. Structural Form: Adopt a truss-type lifting frame composed of upper chords, lower chords, web members, and lifting points. The upper and lower chords are made of hot-rolled H-section steel, and the web members are made of seamless steel pipes. Each member is connected by bolts, featuring a lightweight structure and strong load-bearing capacity.
3. Load Calculation: The total load formula is Q=1.1×(G1+G2)+W, where G1 is the self-weight of the prefabricated house, G2 is the self-weight of the lifting frame, W is the wind load, and the dynamic load coefficient is taken as 1.1.
4. Strength and Stability: Model and calculate the stress values of each member using finite element analysis software to ensure they do not exceed the allowable stress of the material; the maximum deflection does not exceed 1/200 of the span; and perform stability checks on compressed members.
5. Lifting Point Setting: The lifting points are set at the nodes of the upper chords, with the number determined according to the weight and dimensions of the house (usually 4) to ensure uniform force distribution. The lifting lugs are welded with steel plates, and the welding quality must meet the standards.

II. Material Selection

1. Steel: The upper and lower chords are made of Q345B grade H-section steel (yield strength ≥ 345MPa), and the web members are made of Q235B grade seamless steel pipes (yield strength ≥ 235MPa), with no cracks, folds, or other defects on the surface.
2. Connecting Materials: Bolts are made of 8.8-grade high-strength bolts, and welding rods comply with the provisions of the "Technical Conditions for High-Strength Large Hexagon Head Bolts for Steel Structures" (GB/T1231-2006).

III. Construction Preparation

1. Construction Organization: Clarify the responsibilities of the project manager, technical leader, and construction team to ensure the implementation of plan preparation, technical disclosure, progress management, and other work.
2. Materials and Equipment: Prepare prefabricated components (floor slabs, walls, stairs, etc.), lifting equipment (truck cranes, tower cranes), auxiliary materials (safety belts, protective nets), and construction equipment (construction elevators, scaffolding).
3. On-site Layout: Divide the construction area, material storage area, and living area, lay temporary roads, and set up drainage facilities to ensure smooth transportation.

IV. Construction Process

1. Component Transportation: Select transportation vehicles according to dimensions and weight, and secure them firmly to prevent displacement or damage.
2. Component Lifting: Check the integrity of equipment and lifting tools, select appropriate lifting equipment, and ensure stability before temporary fixation.
3. Component Connection: Connect components by welding or bolting according to design requirements, ensuring the connection area is clean, dry, and firm, and conduct acceptance after completion.
4. Alignment and Reinforcement: Use a level and plumb bob to align the position and dimensions of components, and reinforce them according to design requirements to ensure material quality.

V. Safety and Quality Assurance

1. Technical Disclosure: Organize all operators to study drawings, risk points, and safety regulations, and sign for confirmation before starting work.
2. Site Preparation: Compact temporary roads and pad gravel and wooden blocks in the component storage area to prevent moisture or cracks.
3. Process Monitoring: Continuously check the stability of equipment and the firmness of lifting tools during the lifting process to prevent component detachment.