Installation

Space frame installation method

What is a space frame structure?
A space frame structure is a highly indeterminate spatial structure composed of multiple members connected by nodes in a specific grid pattern (such as a triangular pyramid or a quadrangular pyramid). It has the following notable features:

Spatial load bearing, lightweight: The members primarily bear axial forces (tension or compression), fully utilizing the material's strength, resulting in a very light structure.
High rigidity and good integrity: As a three-dimensional structure, it offers excellent stability and can effectively withstand loads in all directions.
Excellent seismic performance: Due to its light weight and good integrity, it exhibits low inertial forces during earthquakes, resulting in excellent performance.
Aesthetically pleasing and adaptable: It can be designed into a variety of complex shapes, such as spherical and curved, making it suitable for large-span structures such as stadiums, airport terminals, train stations, industrial plants, and large public buildings.

Main Space Frame Installation Methods
The choice of space frame installation method depends on factors such as the structural form, span, weight, construction site conditions, lifting equipment, and cost. The following are several mainstream methods:

High-Aerial Bulk Assembly Method
Method: The space frame members and nodes are assembled directly at the designed location. This usually requires a full-height scaffold or mobile platform as an operating platform.
Advantages: No large lifting equipment is required, and installation accuracy is easily controlled.
Disadvantages: Requires a large amount of scaffolding, resulting in a long construction period, frequent overhead work, and high safety requirements.
Applicable: Suitable for projects with small spans, where cranes cannot access the structure, or complex structures.

Strip or Block Installation Method
Method: The entire space frame structure is divided into several strip-shaped or block-shaped units on the ground. These units are lifted to the designed location at height using a crane and then assembled and closed in mid-air.
Advantages: Reduces overhead work, with most work completed on the ground. Quality and safety are more easily assured, resulting in higher efficiency.
Disadvantages: Requires larger lifting equipment, and requires high-quality unit division and lifting point design.
Applicable: Suitable for projects where the division does not affect the structural load-bearing performance and where sufficient on-site lifting capacity is available. This is one of the most commonly used methods.

High-Aerial Sliding Method
Method: The space frame is assembled in sections on an assembly platform at one end of the building. Using sliding tracks and traction equipment, the assembled space frame grid units are gradually slid to the designed location.
Advantages: Minimal impact on the site below, allowing for parallel work with other types of work (such as civil engineering and equipment installation), shortening the overall construction period. No large cranes are required.
Disadvantages: Requires the installation of sliding tracks and a traction system, resulting in a high level of technical complexity.
Applications: Particularly suitable for applications requiring equipment or structural construction below the space frame grid and where large cranes cannot be parked on site (such as airport expansions and stadiums).

Overall Hoisting Method
Method: The entire space frame grid structure is assembled on the ground. Multiple large cranes (or multiple sets of jibs) are then used to simultaneously lift the structure to the designed elevation for securing.
Advantages: Ground-based work allows for easy quality control, high assembly efficiency, and minimal overhead work. Disadvantages: Requires the simultaneous operation of multiple large lifting equipment, requiring extremely high technical coordination and high costs. Requires a suitable ground assembly site.
Applicable: Suitable for projects with medium spans, good structural rigidity, and acceptable on-site ground conditions.

Integral Lifting Method / Integral Jacking Method
Method:
Lifting Method: Lifting equipment is installed on the top of columns above the space frame truss or on a specially designed lifting frame. The entire ground-assembled truss is lifted upward into position using steel strands or cables.
Jacking Method: A series of jacking brackets and jacks are installed below the space frame truss to lift the truss upward from the bottom into position.
Advantages: Only one hydraulic synchronization control system is required, eliminating the need for a large crane. Suitable for installing space frame trusses in extremely large spans and at very high heights.
Disadvantages: Highly technically demanding, requiring extremely stringent synchronization control accuracy, and challenging design and implementation.
Applicable: Structures with extremely large spans and heights, such as large stadiums and airport terminals. III. General Construction Process
Construction Preparation:
Technical Preparation: Drawing review, detailed design (BIM technology is widely used), preparation of a specific construction plan (including a lifting plan), and technical briefing.
Material Preparation: On-site inspection of rods, bolt balls/welded balls, sleeves, high-strength bolts, and bearings, including complete material certification documents.
Site Preparation: Site leveling, surveying and setting out (locating axis and elevation), and positioning of cranes, scaffolding, and other equipment.
Foundation and Support Surface Inspection:
Inspect the position, elevation, and flatness of the embedded bearing components to ensure they meet design requirements. This is the first step in ensuring installation accuracy.
Installation Implementation:
Perform the installation according to the selected installation method (e.g., segmented lifting).
Starting with the bearings: Install the bearing units first, gradually expanding toward the center.
Accuracy Control: Measure the space frame grid's downward deflection, elevation, and axis position at regular intervals to ensure they are within the allowable tolerances.
Inspection and Acceptance:
Process Inspection: Check bolt tightening, weld quality, and correct rod installation. Final Acceptance: After installation is complete, measure the deflection (one of the most important indicators), overall dimensions, and elevation of the space frame grid, and create an acceptance record.

Anti-corrosion and Fire-retardant Coating:
Anti-corrosion coating (paint, galvanizing, etc.) and fire-retardant coating are applied according to design requirements and the environment. Painting is sometimes completed before installation, with only touch-ups performed on-site.

IV. Quality Control and Safety Key Points
Quality Control:
Raw Materials: Strictly control incoming materials, especially the torque coefficient and anti-slip coefficient of high-strength bolts.
Installation Accuracy: Strictly control axis, elevation, verticality, and deflection.
Joint Connections: Ensure that the final tightening torque of high-strength bolts meets design requirements, or that weld quality meets standards.
Safety Key Points:
Special Plans: A special safety construction plan must be prepared and strictly approved, especially for large-scale lifting, hoisting, and sliding operations.
Working at Height: Safety nets and lifelines must be provided, and workers must wear safety belts. Hoisting Operations: Appoint a dedicated person to direct the lifting operation, set up security areas, and prohibit standing personnel. Ensure that lifting points are correctly calculated.
Electrical Safety: On-site electricity usage complies with regulations.
Fire Prevention: Obtain a fire permit for hot work and be equipped with firefighting equipment.
Synchronization Control: For overall lifting/jacking, ensure that all lifting points are synchronized, with deviations controlled to the millimeter level to prevent structural deformation or instability.

Summary
Space frame installation is a highly technical and risky system. The keys to success lie in:
Choosing the most economical and reasonable installation method;
Having a detailed and reliable dedicated construction plan;
Making use of an experienced construction team and a strict quality and safety control system.
With technological advancements, BIM modeling and hydraulic synchronized lifting technologies are playing an increasingly central role in the installation of modern large-scale space frame structures.