Introduction: Load Calculation is the Foundation of Steel Grating Selection
As a core material for industrial platforms, maintenance walkways, drainage channel covers, and other applications, the safety and economic efficiency of steel grating directly depend on the accuracy of load calculations. Regulation 92 of Singapore’s Factories (Shipbuilding and Ship-repairing) Regulations explicitly stipulates that any plank forming a working platform must be capable of sustaining a load of 670 kilogram-force per square metre having regard to the distance between the supports thereof. This statutory requirement establishes a clear technical baseline for steel grating load calculations.
However, in practical engineering, faced with various load types such as uniformly distributed loads, concentrated loads, dynamic loads, and static loads, how does one accurately calculate and select the appropriate product? This article systematically analyzes the core principles and methods of steel grating load calculation based on Singapore’s Factories Regulations, the Public Utilities Board (PUB) Code of Practice on Surface Water Drainage, and relevant industry standards, providing an actionable engineering guide.
Chapter 1: Legal Basis and Technical Standards for Load Calculation
1.1 Core Requirements of Singapore's Factories Regulations
Regulation 92 of Singapore’s Factories (Shipbuilding and Ship-repairing) Regulations specifies the load capacity requirements for working platforms:
| Clause | Technical Requirement | Scope of Application |
|---|---|---|
| Reg. 92(2) | Planks must be capable of sustaining a load of 670 kgf/m² (having regard to support spacing) | All planks forming a working platform |
| Reg. 92(3) | Metal plates must be provided with a slip-resistant surface | Metal working platforms |
| Reg. 92(4) | Projection of plank beyond end support: not less than 50 mm, and not exceeding 4 times plank thickness | Prevention of tipping or lifting |
Technical Note: 670 kgf/m² is equivalent to 6.57 kN/m². This is the minimum safety requirement for working platform design. In practice, load values should be appropriately increased based on the specific application scenario.
1.2 Relevant Requirements from Singapore PUB Drainage Code
PUB’s Code of Practice on Surface Water Drainage (Seventh Edition, December 2018, with amendments under Addendum No. 3 – April 2025) specifies load requirements for drainage channel covers:
| Application Scenario | Load Class | Test Load | Applicable Standard |
|---|---|---|---|
| Pedestrian areas, green belts | B125 | 125 kN | EN 124 |
| Footpaths, cycle tracks | C250 | 250 kN | EN 124 |
| Carriageways, parking areas | D400 | 400 kN | EN 124 |
| Ports, heavy load areas | E600 | 600 kN | EN 124 |
1.3 Load Classification Standards in Industry Practice
Combined with Singapore industrial practice, bangtu’s official website technical article indicates that steel grating load grades can be classified according to the following standards:
| Load Grade | Uniform Load Range | Point Load Range | Application Scenario |
|---|---|---|---|
| C250 | 250 kg/m² | 2.5 kN | Commercial area pedestrian walkways |
| D400 | 400 kg/m² | 4.0 kN | Industrial area maintenance platforms |
| E600 | 600 kg/m² | 6.0 kN | Heavy industry, port terminals |
Chapter 2: Load Types and Calculation Methods
2.1 Load Classification
According to Singapore engineering practice, the load types to be considered for steel grating include:
| Load Type | Definition | Example | Calculation Considerations |
|---|---|---|---|
| Dead Load | Loads permanently acting on the structure | Self-weight of steel grating, weight of fixed equipment | Calculate based on actual weight, partial factor γ_g = 1.1 |
| Live Load | Temporary loads acting on the structure | Personnel, tools, temporary storage | Determine based on application scenario, partial factor γ_q = 1.3 |
| Uniformly Distributed Load (UDL) | Load uniformly distributed over the panel surface | Personnel access, snow accumulation | Unit: kN/m² |
| Concentrated Load | Load acting on a local area | Equipment legs, wheel loads | Unit: kN |
| Dynamic Load | Load accompanied by vibration or impact | Forklift traffic, machinery operation | Consider dynamic amplification factor (1.2-1.5) |
2.2 Uniformly Distributed Load Calculation Method
Under a uniformly distributed load, the bending moment formula for steel grating is:
M_max = q × L² / 8
Where:
M_max: Maximum bending moment (kN·m/m width)
q: Design value of uniformly distributed load (kN/m²)
L: Support span (m)
Engineering Example:
An industrial platform uses G405/40/150 steel grating, support span 1.2 m, design uniformly distributed load q = 5.0 kN/m²:
M_max = 5.0 × 1.2² / 8 = 0.9 kN·m/m width
2.3 Concentrated Load Calculation Method
Under a concentrated load, the bending moment formula for steel grating is:
M_max = P × L / 4
Where:
P: Design value of concentrated load (kN)
L: Support span (m)
Engineering Example:
A maintenance platform承受 a forklift single wheel load P = 20 kN, support span 1.2 m:
M_max = 20 × 1.2 / 4 = 6.0 kN·m/m width
2.4 Deflection Control Standards
Although Singapore’s Factories Regulations do not directly specify deflection limits, internationally accepted standards (ISO 14122-2) require:
Maximum deflection limit: ≤ L/200 (L = support span)
Permanent set requirement: After unloading, permanent set ≤ 0.2% of span
Control purpose: Prevent weld fatigue, ensure 25-year service life
Chapter 3: Influence of Support Span on Load Capacity
3.1 Relationship Between Span and Load Capacity
For the same steel grating, different support spacing results in vastly different load capacities. A rule of thumb: bearing bar height is approximately 1/20 of the span. For example, for a 1-meter span, a bearing bar height of at least 50 mm is recommended.
3.2 Reference Allowable Spans for Different Specifications
| Type | Bar Size | Allowable Span @ UDL 3.0 kN/m² | Allowable Span @ UDL 5.0 kN/m² | Allowable Span @ Concentrated Load 1.5 kN |
|---|---|---|---|---|
| G303/30/100 | 30×3 mm | 0.9 m | 0.7 m | 1.2 m |
| G325/30/100 | 32×5 mm | 1.2 m | 1.0 m | 1.5 m |
| G405/40/150 | 40×5 mm | 1.5 m | 1.2 m | 1.8 m |
| G505/40/150 | 50×5 mm | 1.8 m | 1.5 m | 2.2 m |
Data Source: Calculated based on Q235B material, safety factor 1.8.
3.3 Statutory Requirements for Support Design
Regulation 92(4) of Singapore’s Factories (Shipbuilding and Ship-repairing) Regulations specifies requirements for support design:
The distance a plank projects beyond its end support: not less than 50 millimetres
The distance a plank projects beyond its end support: not exceeding 4 times the thickness of the plank
Unless effectively prevented from tipping or lifting
Chapter 4: Slip Resistance Performance and Safety Requirements
4.1 Statutory Requirements for Slip Resistance
Regulation 92(3) of Singapore’s Factories (Shipbuilding and Ship-repairing) Regulations explicitly states: Any metal plate forming a working platform must have a slip-resistant surface.
4.2 Methods for Achieving Slip Resistance
| Slip Resistance Solution | Technical Parameter | Application Scenario | Load Calculation Considerations |
|---|---|---|---|
| Serrated Bearing Bars | Friction coefficient ≥0.8 | General industrial platforms | Load capacity same as flat bars |
| Serrated Bars + Epoxy Coating | Friction coefficient ≥0.9 | Oily environments | Consider coating effect on load capacity |
| Embedded Corundum Grit | Friction coefficient ≥1.0 | High safety requirement areas | Consider additional self-weight |
Chapter 5: Load Class Comparison Table (Applicable to Singapore Market)
5.1 Recommended Load Classes by Application Scenario
| Application Scenario | Uniform Load Range | Concentrated Load | Recommended Type | Recommended Support Spacing |
|---|---|---|---|---|
| Commercial Pedestrian Walkways | 3.0-4.0 kN/m² | 1.5 kN | G325/30/100 | ≤1.2 m |
| Industrial Maintenance Platforms | 5.0-6.0 kN/m² | 3.0 kN | G405/40/150 | ≤1.5 m |
| Forklift Aisles (<2 tons) | 10.0 kN/m² | 20 kN (wheel load) | G505/40/150 | ≤1.2 m |
| Port Terminals | 15.0 kN/m² | 30 kN (wheel load) | G605/40/150 | ≤1.0 m |
| Drainage Channel Covers (Pedestrian) | Class B125 | 125 kN (test) | G325/30/100 | Based on channel width |
| Drainage Channel Covers (Vehicular) | Class D400 | 400 kN (test) | G505/40/150 | Based on channel width |
5.2 Required Section Modulus by Load Class
| Load Class | Required Section Modulus (for 1.2m span) | Recommended Bar Height | Recommended Bar Thickness |
|---|---|---|---|
| 3.0 kN/m² | ≥12 cm³/m width | 32 mm | 5 mm |
| 5.0 kN/m² | ≥20 cm³/m width | 40 mm | 5 mm |
| 10.0 kN/m² | ≥35 cm³/m width | 50 mm | 5 mm |
| 15.0 kN/m² | ≥50 cm³/m width | 60 mm | 6 mm |
Chapter 6: Q&A: Common Questions in Steel Grating Load Calculation
Q1: How is the load class for steel grating determined?
A: Determining the load class requires consideration of the following factors:
Application Scenario: Pedestrian walkways choose C250-D400, industrial platforms choose D400-E600, heavy-duty areas choose E600 and above.
Traffic Type: Personnel only use 3-4 kN/m², light equipment use 5-6 kN/m², forklifts require wheel load calculation.
Regulatory Requirements: Singapore Factories Regulations require working platforms ≥670 kgf/m² (6.57 kN/m²).
Safety Factor: A safety factor of 1.8-2.0 is recommended.
Q2: How are uniformly distributed loads and concentrated loads converted?
A: They cannot be directly converted; calculations must be performed separately, and the most unfavorable condition taken. Rule of thumb:
A 1.5 kN concentrated load ≈ 3.0 kN/m² uniformly distributed load (for a 1.2 m span)
However, under a concentrated load, local stresses may be significantly higher than under a uniformly distributed load.
Q3: How are loads for forklift aisles calculated?
A: Forklift aisles require calculation by the following steps:
Determine the forklift axle load and wheel load (obtainable from equipment specifications).
Consider a dynamic amplification factor (1.2-1.5).
Calculate bending moment using the concentrated load formula.
Compare with the uniformly distributed load calculation result; take the most unfavorable value.
Q4: How can compliance with Singapore regulations be verified?
A: Verification methods include:
Confirming load capacity ≥670 kgf/m² (after considering support spacing).
Confirming metal plates have a slip-resistant surface.
Confirming plank end support meets requirements (≥50 mm and ≤4 times plank thickness).
Requesting load tables or third-party test reports from the supplier.
Engaging a professional engineer for verification calculations if necessary.
Q5: What is the relationship between steel grating service life and load?
A: Relationship between load and service life:
Long-term overloading can lead to weld fatigue, shortening service life.
It is recommended to maintain a 20% margin above the design load.
Regularly inspect for deformation; if deflection exceeds L/200, evaluate the need for replacement.
Chapter 7: Conclusion and bangtu Company's Technical Commitment
Steel grating load calculation is fundamental to ensuring the safety of industrial platforms. The working platform load requirement stipulated in Regulation 92 of Singapore’s Factories Regulations – 670 kgf/m² – is a non-negotiable technical baseline for all selections. In practical engineering, it is necessary to comprehensively consider various conditions such as uniformly distributed loads, concentrated loads, and dynamic loads, integrating factors like support span, slip resistance requirements, and application scenarios to make scientifically sound decisions.
Summary of Load Calculation Process:
Define the Scenario: Determine platform purpose, traffic type, and environmental conditions.
Determine Loads: Select load class based on the application scenario, referencing the minimum requirements of the Factories Regulations.
Calculate Bending Moments: Calculate bending moments under uniformly distributed loads and concentrated loads separately.
Select Type: Choose bearing bar specifications based on the required section modulus.
Verify Deflection: Confirm full-load deflection ≤ L/200.
Check Regulations: Confirm compliance with the 670 kgf/m² requirement and slip resistance provisions.
About bangtu Company
Bangtu Company has specialized in the steel grating field for over two decades. Our products are widely used in industrial platforms, petrochemical facilities, marine engineering, and municipal infrastructure in Singapore and globally. We commit to:
All product lines comply with the load requirements of Singapore’s Factories Regulations; third-party load test reports are available, confirming load capacity ≥670 kgf/m² (verified according to support spacing).
Industrial platform-specific steel grating uses hot-dip galvanizing with coating thickness ≥100μm, ensuring a service life of over 15 years.
All metal plates are standard-equipped with a serrated slip-resistant surface, meeting the requirements of Factories Regulations Regulation 92(3).
Providing full-process technical support from load calculation to selection design, assisting design institutes and construction units in developing technical proposals.
Offering bilingual (Chinese/English) technical specifications and load calculations to meet the bidding requirements of international engineering projects.
Choose bangtu, choose the reliable assurance for your load calculations.
Tel/Whatsapp: +8613363180165
Email: james@bangtuwiremesh.com
Website: www.bangtusteelgrating.com | www.chinawiremesh.ru
Appendix: Referenced Standards and Literature
Singapore Factories (Shipbuilding and Ship-repairing) Regulations, Singapore Statutes Online, Revised Edition 1999 (1 July 1999).
[Link: https://sso.agc.gov.sg//SL/FA1973-RG11/Historical/19990701]PUB Code of Practice on Surface Water Drainage, Seventh Edition, December 2018, with amendments under Addendum No. 3 – April 2025.
[Link: https://www.pub.gov.sg/Professionals/Resources/Code-of-Practices]bangtu Official Website Technical Article: Comparative Analysis of Steel Grating Load Standards for Industrial Zones vs. Commercial Zones – A Comprehensive Guide for the Singapore Market, May 2025.
[Link: https://bangtusteelgrating.com/industrial-zone-vs-commercial-zone]ISO 14122-2, Safety of machinery — Permanent means of access to machinery — Part 2: Working platforms and walkways
EN 124, Gully tops and manhole tops for vehicular and pedestrian areas — Design requirements, type testing, marking, quality control
