Why Large-Span Steel Workshops Demand a Different Approach

A 20,000 m² industrial workshop is not simply a "bigger shed." Once clear spans exceed 30 meters, every decision — structural system, load assumptions, foundation design, erection sequence — has an outsized impact on safety, cost, and schedule.

At Sichuan Shunyao Supply Chain Management Co., Ltd., we deliver large-span steel structure buildings as a full-process service: planning, design, deepening, fabrication, erection, and post-completion support. This guide summarizes the key points we manage on projects of this scale.

1. Start with Three Fundamentals: Geology, Loads, Functional Layout

Before any drawing is produced, three dimensions must be locked down:

• Ground conditions. Special soils such as collapsible loess (common across many industrial zones) require a foundation treatment plan tailored to the geotechnical report — not a copy-paste solution.
• Load assumptions. Spans of 30 m+ make the structure highly sensitive to wind and snow loads. Design values must be calculated against local meteorological standards, not generic assumptions.
• Functional zoning. Production lines, logistics flow, fire compartments, and future expansion all shape the structural grid and envelope design.

Structural system selection: the mainstream options are portal frames, spatial trusses, and space grids. For mid-to-large span industrial buildings, the portal frame remains the workhorse — economical steel consumption, controllable construction time, and the best overall cost-performance ratio.

2. Structural Safety: Steel Grade and Connection Design

The core of a safe structure lies in material selection and joint engineering:

• Main load-bearing members typically use Q355B (or higher) high-strength steel, with mechanical properties and weldability matching the design code.
• Critical connections combine high-strength bolting with welding to avoid stress concentration, with fatigue verification performed per the Standard for Design of Steel Structures.
• Roof systems use profiled steel sheeting with composite insulation; purlin spacing is set by wind-uplift calculation to prevent panel failure under extreme weather.
• Fire protection is zoned by function: coating thickness and fire-resistance ratings are determined per code for each compartment, not applied uniformly.

3. Erection Quality: Where Projects Are Won or Lost

Fabrication quality means little if site erection is not controlled. On large-area steel projects we manage three critical variables:

① Erection unit planning. The structure is divided into installation units sized to match the rated capacity of available cranes — no improvised lifts.

② Anchor bolt precision. Embedded anchor bolt deviation is controlled within ±2 mm, eliminating steel column alignment problems before they occur.

③ Welding deformation control. Optimized welding sequences, anti-deformation measures, and strict preheating and inter-pass temperature control on thick plate welds. All Class-1 welds are inspected by a third party using ultrasonic and radiographic testing (UT/RT).

4. Cost Control Without Cutting Corners

A workshop budget has four main blocks: steel procurement, fabrication, transport & erection, and foundation works. Value engineering happens at design stage, where the biggest savings live:

• Replace solid web members with lattice members where appropriate;
• Use higher-strength steel to reduce section sizes and total steel tonnage;
• Specify a double-layer profiled steel sheet + rock wool envelope to balance thermal performance and cost;
• Match foundation type to ground and loads — isolated or strip foundations where conditions allow, prestressed pipe piles for soft soils.

The goal is safety and economy together — not the cheapest tonnage, not over-engineering.

5. One Team, Full Process

For a 20,000 m² project, fragmented responsibilities are the biggest schedule risk. Our integrated delivery model covers: