Steel Hollow Section Capacity Calculator
The SkyCiv Steel Hollow Section Capacity Calculator is a free tool that allows engineers to design steel RHS, CHS, and SHS members. The hollow section beam design software provides results for moment capacity, shear capacity, axial capacity, section and member utilization (including combined checks), as well as a governing case for the member. The free hollow section design tool includes a library of common rectangular, square, and circular hollow sections.
Hollow sections can be designed according to the following design codes:
- Australian Standard - AS 4100:2020 (Metric Units Only)
- American Standard - AISC 360-22 (Metric and Imperial Units)
- Eurocode Standard - EN 1993-1-1 (Metric Units Only)
- New Zealand Standard - NZS 3404:1997 (Metric Units Only)
The hollow section capacity calculator is part of the SkyCiv Quick Design Module.
About the Hollow Section Capacity Calculator
What are Structural Hollow Sections?
Structural hollow sections are closed steel sections which are fabricated in a Rectangular (RHS), Square (SHS) or Circular (CHS) shape. Hollow sections can be fabricated via cold-forming, or hot finishing processes.

Where are Rectangular/Square Hollow Sections Used?
RHS and SHS have very high flexural and torsional stiffness, meaning they can perform better than open sections (I-Section/Channel) of equivalent weight/dimensions. However, the design and fabrication of connections to RHS/SHS sections is typically more complex than an open section, meaning they aren’t always more economical to use in construction.
Where are Circular Hollow Sections Used?
CHS have similar benefits to RHS/SHS members, but benefit from having uniform section properties about any axis. Due to this, CHS members are not susceptible to lateral-torsional or flexural-torsional buckling. This makes CHS members suitable for members with complex biaxial or torsional loading.
Square/Rectangular Hollow Section Design Considerations
AISC 360-22 does not contain guidance for the design of RHS/SHS members with slender flanges and slender webs. A warning will be displayed in the design module for sections of this nature. Note, no standard RHS/SHS have slender webs, but care should be taken when designing custom/built-up RHS/SHS with slender webs.
SkyCiv RHS/SHS/CHS Design Module
The SkyCiv RHS/SHS/CHS Design Module supports the design of standard and Custom RHS/SHS/CHS to AISC 360-22 and AS 4100-2020. The module supports design for Major Axis Flexure, Minor Axis Flexure, Axial Compression/Tension and Major/Minor Shear Force, including combined actions checks. Users can specify buckling lengths for flexure and compression buckling, including specification of effective length factors. Results are presented in a clean, table based format with relevant references to the Design Code. The AISC 360-22 version of the module supports Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD) design, with metric and imperial unit reporting.
Related SkyCiv Software
SkyCiv offers a wide range of Cloud Structural Analysis and Engineering Design Software, including:
- SkyCiv Quick Design
- SkyCiv Connection Design
- I Beam Design Capacity Calculator
- Channel Beam Design Capacity Calculator
- Angle Section Beam Design Capacity Calculator
- Aluminum Design Calculator
- Cold Formed Steel Beam Design
- Weld Group Capacity Software
- Bolt Group Capacity Software
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