Structural Hollow Sections

Structural Hollow Sections (SHS) and Rectangular Hollow Sections (RHS) are essential components in modern construction and engineering projects. These versatile steel profiles come in various sizes and specifications, making them suitable for a wide range of applications. In this comprehensive guide, we'll explore the world of SHS and RHS, delving into their sizes, applications, and key considerations for selection.

What are the standard sizes for SHS and RHS pipes?

When it comes to Structural Hollow Sections (SHS) and Rectangular Hollow Sections (RHS), understanding the standard sizes is crucial for engineers, architects, and construction professionals. These steel profiles are available in a wide range of dimensions to suit various project requirements.

For SHS pipes, which have a square cross-section, common sizes typically range from 20mm x 20mm up to 1200mm x 1200mm. The wall thickness can vary from 1.6mm to 16mm, depending on the structural requirements. Some of the most frequently used SHS sizes include:

- 50mm x 50mm

- 75mm x 75mm

- 100mm x 100mm

- 150mm x 150mm

- 200mm x 200mm

- 250mm x 250mm

- 300mm x 300mm

- 350mm x 350mm

- 400mm x 400mm

- 450mm x 450mm

- 500mm x 500mm

- 750mm x 750mm

- 600mm x 600mm

- 800mm x 800mm

- 900mm x 900mm

- 1000mm x 1000mm

- 1200mm x 1200mm

RHS pipes, characterized by their rectangular cross-section, offer even more flexibility in terms of dimensions. Standard sizes for RHS can range from 50mm x 30mm up to 500mm x 300mm or larger. Wall thicknesses are similar to those of SHS, ranging from 1.6mm to 16mm. Popular RHS sizes include:

- 50mm x 25mm

- 75mm x 50mm

- 100mm x 50mm

- 150mm x 100mm

- 200mm x 100mm

- 300mm x 200mm

- 400mm x 200mm

- 500mm x 300mm

- 600mm x 200mm

- 600mm x 300mm

- 800mm x 400mm

- 800mm x 500mm

- 1000mm x 500mm

- 1200mm x 1000mm

- 1200mm x 800mm

It's important to note that these sizes are not exhaustive, and manufacturers may offer custom dimensions to meet specific project needs. The choice of size depends on various factors, including load-bearing requirements, architectural design, and the specific application of the structural member.

When selecting the appropriate size for SHS or RHS pipes, engineers must consider several factors:

1. Load-bearing capacity: Larger sections and thicker walls generally provide greater strength and load-bearing ability.

2. Span length: The required length of the structural member influences the size selection.

3. Weight considerations: Balancing strength with overall structure weight is crucial for efficient design.

4. Aesthetic requirements: In some cases, the visible profile of the sections may influence size selection for architectural reasons.

5. Connections and joints: The chosen size must be compatible with the planned connection methods and other structural elements.

Understanding these standard sizes and their applications is essential for optimizing structural design and ensuring the longevity and safety of construction projects. Always consult relevant design codes and standards, such as AS/NZS 1163, when specifying SHS and RHS pipes for your project.

How does AS 1163 pipe specification apply to SHS?

AS 1163, the Australian Standard for structural steel hollow sections, plays a crucial role in defining the specifications for AS 1163 Pipe SHS (Square Hollow Sections) and other structural hollow profiles. This standard ensures that the steel sections used in construction and engineering projects meet stringent quality and performance criteria.

The AS 1163 specification covers several key aspects of SHS pipes:

1. Material Grades:

AS 1163 defines different grades of steel used for SHS, with the most common being C350 and C450. These grades indicate the minimum yield strength of the steel, with C350 having a yield strength of 350 MPa and C450 having 450 MPa. The choice of grade depends on the specific structural requirements of the project.

2. Manufacturing Process:

The standard specifies that SHS pipes should be manufactured using electric resistance welding (ERW) or a similar approved process. This ensures consistency in the weld quality and overall structural integrity of the sections.

3. Dimensional Tolerances:

AS 1163 sets out strict tolerances for the dimensions of SHS pipes, including:

External dimensions (width and depth)

Wall thickness

Straightness

Squareness of sides

Twist

These tolerances ensure that the SHS pipes meet the required specifications and can be reliably used in structural calculations and designs.

4. Surface Finish and Coatings:

The standard outlines requirements for surface finish, including acceptable levels of surface imperfections. It also provides guidelines for protective coatings, such as galvanization, which can be applied to enhance corrosion resistance.

5. Mechanical Properties:

AS 1163 specifies the required mechanical properties of AS 1163 Pipe SHS, including:

Tensile strength

Yield strength

Elongation

Impact toughness (for certain grades and thicknesses)

These properties are crucial for ensuring that the SHS pipes can withstand the expected loads and environmental conditions in their intended applications.

6. Testing and Inspection:

The standard mandates various tests and inspection procedures to verify compliance with the specified requirements. These may include:

Tensile tests

Flattening tests

Visual inspections

Non-destructive testing of welds

7. Marking and Documentation:

AS 1163 requires that SHS pipes be marked with specific information, including the manufacturer's name or trademark, the steel grade, and the standard designation. This ensures traceability and helps verify that the correct materials are being used on-site.