Concrete prefabricated residential structures represent a relatively new industry, lacking a fully developed industrial production system. Current construction technologies are insufficient to meet the demands of modern residential industrialization.
Key components of industrialized residential buildings—including architectural decoration, electrical systems, and equipment—must be pre-planned and embedded during factory production. Therefore, before manufacturing prefabricated components, detailed designs for electrical, equipment, production, and lifting processes should be finalized.
Prior to constructing prefabricated residential buildings, a comprehensive construction organization plan is essential. This plan should incorporate advanced, efficient construction methods and a reliable quality control system to ensure successful completion, from component fabrication to the finished residential structure.
Construction Method Characteristics and Principles
1. Construction Method Characteristics
The prefabricated concrete assembly structure fully leverages factory production advantages by standardizing component design, manufacturing, transportation logistics, and specialized installation. This approach enhances construction efficiency and significantly reduces construction waste.
1. Prefabricated Component Design Standards and High Production Accuracy
This project’s prefabricated components include wall panels, composite sun slabs, composite panels, stairs, bay windows, and decorative panels. Uniform cross-sectional dimensions and reinforcement designs ensure standardized production. Strict controls during manufacturing maintain precise cross-sectional dimensions, accurate steel bar placement, and component flatness and perpendicularity.
2. Production, Transportation, and Supporting Facilities
Component production and transportation plans are prepared in advance based on usage requirements. These plans align with the overall project schedule to ensure a coordinated supply chain for production, transportation, and on-site installation, enabling smooth workflow.
3. Component Lifting Sequence
Using the component layout of the standard unit, a “far to near” lifting sequence is followed to optimize tower crane operations. Components are sequentially numbered to control and manage the hoisting order effectively.
4. Convenient and Rapid Tool Support
Tools for quick support and positioning are designed according to component stress characteristics. Embedded supports are incorporated during component production and concrete pouring at cast-in-place locations to facilitate efficient support and accurate positioning.
5. Reduced Quality Issues
The prefabricated exterior wall panels use a sandwich insulation system that effectively addresses common issues like leakage, cracking, hollow bricks, and detachment through brick reverse punching technology and tongue-and-groove joint designs. Factory production eliminates frequent problems such as damage to drip and decorative lines and significant deviations in room dimensions.
6. Reliable Component Connections
Connections between prefabricated components and cast-in-place structures are designed according to stress requirements to ensure structural integrity and deformation resistance. Wall panels are joined using sleeve grouting technology; composite components are connected by binding steel bars and pouring concrete; bay windows, stairs, and decorative panels are attached via bolts or welding. After connection, concrete is poured at nodes to form a unified, durable structure.
7. Enhanced Construction Safety
Factory-processed prefabricated wall panels, bay windows, and decorative panels reduce facade decoration work. The cast-in-place nodes between prefabricated wall panels use integrated prefabricated concrete insulation and decoration formwork, eliminating difficulties with external formwork support and lowering safety risks during insulation construction and external finishing.
8. Improved Labor Efficiency
Traditional cast-in-place construction involves reinforcing steel binding, formwork support, concrete pouring, and external insulation and finishing. Prefabricated residential buildings consolidate many of these steps into factory production, reducing on-site construction complexity and significantly boosting labor productivity.
9. Energy Savings and Emission Reduction
Factory production reduces material waste, while on-site wet operations are minimized, lowering construction debris generation. Reduced formwork use decreases wood consumption, and less on-site steel and concrete work cuts water and electricity usage, as well as noise and pollutant emissions, resulting in considerable environmental benefits.
2. Construction Technology Principles
The square integrated decoration style employs synchronous installation of prefabricated components alongside cast-in-place operations. Prefabricated wall panels and cast-in-place walls are constructed simultaneously. After wall panel installation, sleeve grouting connects steel bars and panels, followed by casting at nodes to form a continuous structure.
Prefabricated composite components are installed in sync with cast-in-place floor slabs, integrating through composite concrete pouring.
Structural construction also includes installing prefabricated stair boards, decorative panels on each floor, and staggered bay window installation. Use of prefabricated concrete insulation and decoration integrated formwork resolves external formwork support issues at cast-in-place nodes between wall panels.
This method rigorously controls quality at every stage—transportation, storage, lifting, installation, connections, cast-in-place node treatment, and finished product protection. Extensive use of specialized tools for lifting, support, and installation ensures convenient assembly, reliable quality, higher labor productivity, and significant energy-saving and emission reduction benefits.
Key Installation and Node Construction Points for Prefabricated Wall Panels
1. Process Flow
Preparation → Hoisting → Rapid positioning → Installation of inclined supports → Fine adjustment → Steel bar binding at cast-in-place nodes → Embedding of mechanical and electrical boxes and conduits → Grouting → Formwork support for cast-in-place walls and nodes → Installation of integrated prefabricated concrete insulation and decoration formwork → Concrete pouring
2. Preparation Before Installation
Operators undergo training to emphasize the critical importance of grouting quality, understanding its irreversible nature. Simulation training standardizes grouting procedures and highlights essential control points.
Grouting materials are stored in dedicated, rainproof, well-ventilated warehouses on raised racks to maintain dryness and temperature control.
Necessary equipment includes measuring cylinders, buckets, mixers, grouting cylinders, and electronic scales. Grouting material quantities are calculated based on the number of wall panels.
Surfaces of wall panels and cast-in-place structures must be thoroughly cleaned—free of oil, dust, adhesives, chips, or loose fragments. Contact surfaces are moistened without water pooling to ensure tight grout joints and prevent leakage.
3. Hoisting of Prefabricated Wall Panels
Prefabricated components use single-sided numbered lifting beams with dual lifting points to streamline operations and reduce time spent repositioning lifting ropes.
Wall panels are lifted using modular beams, attaching steel wire ropes to reserved lifting rings with shackles. After lifting about 500mm off the ground, components undergo quality and connection checks before continuing. Protective full-length boards are nailed to panel corners to prevent damage during lifting, which is performed slowly and evenly.
During hoisting, tower cranes lift panels slowly to about 600mm above the working surface. Construction personnel use slip ropes hooked to the panel to guide and gently lower it into place.
4. Wall Panel Positioning
Auxiliary tools and instruments ensure fast and precise positioning. Wall panels connect to reserved grouting sleeves using cast-in-place structural roof steel bars. Quick positioning during hoisting is followed by diagonal supports for alignment and fixation. Once calibrated, cement-based grout is injected with a grouting gun to seal steel bar connections, forming a unified structure.
5. Installation of Diagonal Supports
Diagonal supports are bolted to connections between prefabricated and cast-in-place panels, allowing initial adjustments to achieve vertical alignment. Temporary adjustable diagonal supports secure the panels until short diagonal supports replace them for fine calibration.
6. Fine Adjustment After Positioning
Diagonal braces with adjustable lengths (±100mm) are installed on the panel floor. Precision adjustments correct panel position in all directions relative to pre-set control lines.
7. Reinforcement Binding at Cast-in-Place Nodes
Steel reinforcement is securely bound at cast-in-place nodes to ensure structural integrity.
8. Mechanical and Electrical Box and Conduit Embedding
A specialized wire box design with two steel conduit sleeves is used to prevent displacement during embedding. Additional positioning steel bars are firmly tied to main reinforcement bars for stability.
9. Wall Panel Grouting
This comprehensive construction process covers production, transportation, storage, lifting, installation, connection, and cast-in-place node treatment of wall panels. Specialized lifting, positioning, and installation tools make the assembly process efficient and reliable, ensuring high-quality construction and increased labor productivity.
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