This article presents a detailed engineering case study of a 66x75m steel structure warehouse measuring 66 meters in width and 75 meters in length. Designed in accordance with the Technical Code for Light-weight Steel Structures (GB51022-2015), the project adopts a portal steel frame system to meet specific spatial and functional demands. The layout reflects a deliberate balance between structural efficiency and operational flexibility.

66X75m Steel Structure Warehouse Design Plan

The warehouse is divided into three spans: two side spans of 24 meters and a central span of 18 meters. This configuration accommodates internal vehicular access through the center aisle. The eaves height is 5.5 meters.

Structural Materials

• Primary structure: Fabricated using Q355B high-strength steel
• Secondary members: Constructed with Q235B steel
• Roof composition:
  • Outer cladding: 0.5 mm corrugated steel sheet
  • Thermal insulation: 75 mm glass wool
  • Interior ceiling: 0.4 mm steel liner

This layered system ensures both thermal performance and structural durability.

Span Arrangement and Column Grid

The warehouse spans 66 meters in width, arranged asymmetrically to accommodate functional zoning. While symmetrical frames are generally more economical, the client’s operational requirements necessitated a central 18-meter corridor for internal circulation.

The building length of 75 meters is segmented into ten equal bays at 7.5 meters each, creating a regular column grid that facilitates consistent load distribution and simplifies purlin installation.

Roof Beam Splicing Strategy

Efficient splicing of roof beams plays a crucial role in balancing transportability, structural integrity, and construction cost. Key design principles include:

• Splice location: Positioned near points of contraflexure (typically 1/4 to 1/6 of the span) to minimize internal stress concentrations.
• Transport limitations: Beam segments are kept under 12.5 meters to ensure ease of transportation.
• Minimizing splice count: Fewer joints reduce fabrication time and limit the need for end plates and high-strength bolts.
• Avoiding critical intersections: Splices are placed away from intersections with bracing members, such as wind columns or roof ties, to prevent interference.

Following this rationale, the 66-meter roof beam is divided into seven segments. Splice nodes A and D are situated at column intersections, while the ridge (Node F) remains continuous due to concentrated bending moments and the presence of lateral ties.

Load Analysis

Dead Load

The calculated dead load includes all permanent components of the roofing system:

Component	Approx. Weight (kg/m²)
Corrugated steel sheet	5.0
Glass wool insulation (75mm)	1.05
Ceiling liner panel	3.5
Purlins and accessories	~4.0
Bracing systems	~2.0
Total	~15.0 kg/m² (~0.15 kN/m²)

Load per frame: 0.15 kN/m² × 7.5m = 1.125 kN/m

Live Load

According to GB standards:

• Basic roof live load = 0.3 kN/m²
• Suspended equipment allowance = 0.1 kN/m²
• Total live load: 0.4 kN/m² × 7.5m = 3.0 kN/m

Wind Load

The design wind load is taken as 0.4 kN/m². Due to the building’s considerable width (66m), which exceeds the 60m threshold, additional bracing is introduced on interior gridlines (axes B and C) to comply with code stipulations and enhance lateral stability.

The structural layout of the 66X75m Steel Structure Warehouse

The structural layout adheres to conventional portal frame principles. Given the absence of overhead cranes, column bases are designed as hinged supports. The central columns act as swing supports, facilitating horizontal load distribution without compromising vertical stability.

Bracing systems are incorporated at both ends and intermediate sections of the frame to maintain structural coherence under lateral forces. Their placement reflects both spatial considerations and codified support intervals.

Foundation and Stability Considerations

66x75m steel structure warehouse without cranes or multi-story mezzanines, column footings may be safely hinged, reducing complexity and cost. However, for facilities with dynamic loads or elevated operational platforms, rigid connections and reinforced foundations are required to ensure overall stability.

Design Compliance and Code Reference

All structural elements and load calculations strictly follow the provisions of:

• GB50017-2017 (Standard for Structural Steel Design)
• GB51022-2015 (Technical Specification for Portal Frame Steel Structures)

These standards provide the regulatory framework for ensuring the structure’s safety, serviceability, and long-term durability.

Conclusion

The design of the 66x75m steel structure warehouse showcases a thoughtful integration of client-specific spatial requirements with structural engineering principles. By optimizing the portal frame layout, carefully selecting splice points, and adhering to national codes, the project achieves both functional clarity and structural resilience. The outcome is a warehouse design that balances practicality, economy, and performance.

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