Latest Steel Structure Design Standards 2025

1. Steel Structure Design Standards According to National Regulations

Hai Long Construction Joint Stock Company is proud to apply advanced steel structure design standards, meeting the strict requirements of each country, ensuring superior quality for every project.

1.1. Steel Structure Design Standards in Vietnam

In Vietnam, the main steel structure design standards are specified by TCVN 5575:2012, originating from Russian technical standards. This is a detailed set of regulations, requiring all design and construction processes to strictly comply with important safety factors, including:

• Load safety factor: Ensure the structure's ability to withstand external impacts.
• Material safety factor: Regulations on the quality and durability of steel used in construction.
• Working environment safety factor: Protect labor safety and minimize risks during operation.

This standard pays special attention to stiffness , and stability of steel structures, to prevent deformation beyond the allowable threshold.

• In terms of calculation, the design strength is determined by the formula: Standard Strength / Material Safety Factor.
• Meanwhile, the calculated load is established based on: Standard load × Load reliability factor.

1.2. Steel Structure Design Standards According to AISC 89/ASD of the US

In addition to steel structure design standards in Vietnam, the US standard **AISC 89/ASD** is currently trusted and applied by many general contractors, including Hai Long Construction Joint Stock Company, thanks to its accuracy and flexibility in large-scale projects.

According to AISC 89/ASD standard, internal force values ​​such as **M (bending moment)**, **N (axial force)** and **Q (shear force)** are calculated based on standard loads without applying overload factors. However, to ensure safety and optimize design, internal forces are determined through the combination of specific **load combinations**, suitable for each type of construction.

Steel sections in American standards are classified into three main groups:
- Compact Section: Requires full exploitation of material performance to achieve maximum durability.
- Slender Section: The allowable stress must be reduced to ensure safety against deformation.
- Non-Compact Section: Material stress also needs to be adjusted to decrease accordingly.

The highlight of AISC 89/ASD is the ability to accept local warping in steel sections, while allowing some cross-section parts to not participate in load-bearing. This leads to a reduction in allowable stress, while also setting strict regulations on the slenderness of components such as beam webs, beam flanges, column webs and column flanges. As a result, the design of steel structures according to American standards not only ensures durability but also optimizes the efficiency of material use, suitable for projects with high technical requirements.

1.3. Steel Structure Design Standards According to European Eurocode 3

Standard Eurocode 3 is the leading steel structure design standard in Europe, flexibly applied by Hai Long Construction Joint Stock Company in international projects. The calculation process according to Eurocode 3 is based on two main limit states: Ultimate Limit State , and Serviceability Limit State. The limiting stress is determined by taking yield limit of the material multiplied by appropriate correction factors.

Section Classification

Steel sections in Eurocode 3 are divided into four classes based on width/thickness ratio (thinness):

• Level 1 and 2: Flexible and dense cross-section, with large thickness, allowing higher calculated stress thanks to superior load-bearing capacity.
• Level 3 and 4: The cross section is not solid and thin, easily causing local instability, requiring a reduction in allowable stress to ensure safety.
  This classification is similar to Vietnamese standards (TCVN) and American standards (LRFD), helping to optimize the design according to each material and construction characteristic.

Load Calculation

Loads according to Eurocode 3 are determined based on BS 6399, include:

• Floor load: Evenly distributed or concentrated depending on the function of the project.
• Wind load: Calculated from wind pressure based on wind speed, where the aerodynamic coefficient needs to be considered as well negative pressure inside construction. To ensure safety, the most dangerous aerodynamic coefficient value must be selected in the calculation.
• Snow load: Depends on regional climate conditions.

Displacement and Safety Factor

The allowable displacement is defined as the maximum value from service load (live load), no overload factor is applied. Compared to TCVN, Eurocode 3 allows the level larger deformation, suitable for projects requiring flexibility. The safety factor in BS 6399 is flexibly adjusted according to each type of load, but does not specify a factor related to the function of the project or the working factor of the structure - a difference compared to TCVN.

Compare with TCVN

When comparing the total Safety factor (HSAT), TCVN usually has a smaller value than BS in Eurocode 3. This means that, with the same type of steel and nominal load, designing according to TCVN will save more materials than Eurocode 3. However, Eurocode 3 brings flexibility and high reliability, suitable for international projects that Hai Long Construction Joint Stock Company is aiming for.

2. Design Load Standards According to Each Country's Regulations

Design load is a core factor in the process of designing steel structures, which is specified separately according to the standards of each country to ensure the safety and sustainability of the project. Hai Long Construction Joint Stock Company always strictly adheres to these standards, providing optimal solutions for every project. Below are some typical design load standards:

• Vietnam: TCVN 2737:1995 – Detailed regulations on loads and impacts on the structure.
• Mỹ: UBC 97, MBMA 2002, IBC 2006 – Popular standards in steel structure design in the United States.
• British:
  • BS 6399: Part 1:1984 – Standards on static load and load in use.
  • BS 6399: Part 2:1997 – Instructions for calculating wind loads for construction.
• Europe: EN 1991-1-4:2005 A1 – Comprehensive standards for load effects, especially wind loads.
• Uc: AS / NZS 1170.1: 2002 , and AS / NZS 1170.2: 2011 – Specify static and dynamic loads such as wind and snow.

Factors Affecting Design Loads

Design loads are influenced by many external factors, including:

• Construction site conditions: Topography, geology and geographical location of the project.
• Weather impact: Wind, snow, rain and other climatic phenomena typical of each region.

Although each country applies its own standards, the basic principles in load calculation still play an important role in ensuring effective load-bearing steel structures, avoiding risks and errors in construction. With extensive experience, Hai Long Construction Joint Stock Company not only complies with national standards but also flexibly applies international standards, meeting all strict requirements from customers.

3. Important Notes When Applying Steel Structure Design Standards

To ensure the quality and efficiency of steel structure works, the application of design standards must be carried out carefully. Hai Long Construction Joint Stock Company recommends that investors pay attention to the following factors:

3.1. Financial Capacity Assessment

Budget is a prerequisite when choosing design standards. Investors need to consider carefully to ensure that the steel structure design solution is both cost-optimized and meets the technical requirements of the project.

3.2. Built Environment Analysis

The construction environment plays an important role in the application of design standards. It is necessary to assess whether the climatic conditions, terrain and external factors are suitable for implementing the chosen standard. Careful study of the site characteristics – from geology to weather – helps ensure the stable and sustainable operation of steel structures.

3.3. Synchronization in Design and Construction

Once a specific standard has been decided upon, it is essential to maintain consistency throughout the entire process from design to construction. This consistency not only improves efficiency but also ensures the safety and longevity of the project.

3.4. Avoid Mixing Standards

Combining different design standards in the same project can lead to inconsistencies, seriously affecting the safety and quality of steel structures. Hai Long Construction Joint Stock Company always recommends that investors adhere to a single standard to ensure optimal results.