Prefabricated House Hoisting Design Specification
The Prefabricated House Hoisting Design Specification primarily covers three core aspects: hoisting point location, hoisting accuracy control, and acceptance inspection, with specific requirements as follows:
I. Requirements for Hoisting Point Location
Hoisting point design must balance structural safety and construction convenience. Symmetry is a fundamental principle, with hoisting points symmetrically arranged to prevent component tilting or eccentric loading. The number of hoisting points is determined by component size: beams and slabs with a length ≤ 6 meters require at least 2 hoisting points; for components longer than 6 meters, an additional hoisting point is needed for every 3 meters of increase, e.g., a 9-meter-long beam requires 3 hoisting points. The spacing must meet dual constraints: the distance between hoisting points should not exceed one-third of the component's length, and the distance from the component's end should not be less than 200 millimeters, e.g., for a 12-meter-long component, the maximum hoisting point spacing is 4 meters, with an end distance of at least 200 millimeters. Position avoidance is a critical detail; hoisting points should avoid embedded pipelines, reinforced areas, and joint locations, e.g., hoisting points for composite slabs should be ≥ 300 millimeters from the slab edge to prevent damage to embedded parts or affect structural connections.
II. Hoisting Accuracy Control Standards
Accuracy control directly impacts component installation quality and overall building stability. Horizontal position deviation requirements are stringent, with the planar position deviation of vertical components such as prefabricated wall panels and columns needing to be controlled within ±5 millimeters. Verticality deviation is managed by height segment: components with a height ≤ 6 meters allow a deviation of 5 millimeters; for components taller than 6 meters, the total verticality deviation should be ≤ 10 millimeters, and the inter-story verticality deviation should be less than H/1000 (H being the component height), e.g., for a 10-meter-high component, the inter-story deviation should be < 10 millimeters. Elevation control requires the top surface elevation deviation of prefabricated components to be ≤ ±5 millimeters to ensure floor height consistency. Joint width should meet design requirements: horizontal joint width should be controlled between 10-20 millimeters, and vertical joints typically between 15-25 millimeters, with deviations not exceeding ±5 millimeters to prevent structural sealing or load-bearing issues due to excessively wide or narrow joints.
III. Acceptance Inspection Points
Acceptance inspection is a crucial step in ensuring hoisting quality. Component arrival inspection should verify dimensions and the position of embedded parts, focusing on checking the deviation of embedded sleeves, dowels, and reserved holes against design requirements. Hoisting process monitoring should employ high-precision total stations or laser leveling instruments to monitor the component's positioning status in real-time, ensuring dynamic compliance with horizontal position, verticality, and elevation standards. Temporary support system acceptance should inspect the angle between the diagonal brace and the floor (typically 45°-60°), the distance between the support point and the component's connection point (generally ≤ 500 millimeters), and the tightening torque of connecting bolts to prevent component overturning. Joint and grout quality should ensure the bottom grout is full and continuous without voids, with special sealing materials (such as polyethylene foam strips) used at joints to prevent grout leakage, and quality confirmed through visual inspection and tapping tests.
