Designing Steel Space Frames for Snow Loads & Cold Environments: Key Principles You Must Know

 In cold regions or areas with frequent snowfall, snow loads and low temperatures are critical factors that must be carefully addressed in the design of steel truss structures. Neglecting these factors can lead to structural deformation, leaks, excessive snow accumulation, or even collapse. This article will outline how to design steel truss structures under snow load and cold environmental conditions to enhance safety and service life.

1. Snow Load Basics

What is Snow Load: Refers to the vertical load exerted by accumulated snow on the horizontal projected area of a roof or structure. Snow loads are categorized as ground snow loads and roof snow loads, with the more stringent value typically applied.

Code Standards: Numerous codes (e.g., TS EN 1991-1-3 / Eurocode 1-3) specify snow load calculation methods, accounting for factors like climate zones, roof slopes, and roof configurations.

Load Combinations: Snow loads are typically combined with dead loads (self-weight, roofing materials, etc.). Commonly, combined wind loads or mixed rain-snow conditions must also be considered.

2. Factors Influencing Snow Load Design for Space Frame Structures

(1) Roof Slope & Geometry

Steep slopes, curved surfaces, or domes better prevent snow accumulation. Flat roofs or low-slope roofs are more prone to snow buildup.

(2) Roof Support System Density

Closer support points or truss spacing with more frequent members distribute snow load pressure. Otherwise, members or joints bear concentrated stress.

(3) Materials and Connection Details

At low temperatures, steel impact resistance and the performance of welded or bolted joints under thermal expansion/contraction must be ensured. Surface corrosion protection is also critical.

(4) Regional Snow Depth Frequency and Maintenance Cycle

In areas with frequent heavy snowfall, design should account for maximum possible snow depth, with regular snow accumulation inspections required.

3. Classic Snow Load Design Codes and Standards

Eurocode 1-3 (EN 1991-1-3): Common European code for roof snow loads, specifying how snow load parameters interact with roof slope, wind pressure, and temperature.

ASCE 7 Series Standards (USA): Includes detailed provisions for snow loads, snow drifts, and unbalanced snow loads. The latest version imposes stricter design requirements for snow loads.

4. Practical Design Tips

Select Appropriate Roof Slope and Shape

Sloped roofs, curved surfaces, or roofs with drainage slopes significantly reduce the risk of snow accumulation.

Design Sufficient Structural Stiffness and Support Spacing

Ensure dense support between joints and members, with dimensions accounting for load allowances.

Material Selection and Cold Weather Protection

Use steel that maintains strength at low temperatures, considering cold brittleness effects; provide suitable protection for welds and bolted connections; apply freeze-wet protection and high-quality coatings for corrosion resistance.

Combined Snow and Live Load Calculations

Roof live loads (e.g., maintenance personnel, equipment) should not be simply added to snow loads in all cases; unbalanced loads and drift conditions must be considered according to code-specified combination methods.

Regular Maintenance and Snow Removal Plan

Monitor snow accumulation, especially during snow seasons; design snow removal access routes; inspect roof structures for deformation due to snow loads.

Snow loads and cold environments pose significant challenges to steel space truss structures. However, these challenges can be fully overcome through strict compliance with codes, rational design, and appropriate material selection.