Design process

Importance of early engagement


The design process usually comprises an interaction between the architect and structural steel designer to translate the architect’s vision for the project into detailed design drawings and specifications that provide the steelwork supply chain with sufficient information to fabricate and erect the steel structure.

It is of upmost importance that the engineer engages with the architect early in the design process to ensure the most cost-effective, responsive solutions are obtained. It is generally accepted that the ability to influence outcomes decreases over the lifetime of a project, while the cost of change increases over the same period.

Three stages of structural design

In the context of structural design of steel-framed buildings, there are three main stages:

  • Concept design: which includes the layout of the main steel components and the stability strategy for the building (i.e. how the structure is braced)
  • Member design: based on structural analysis of the building and on the client’s loading requirements
  • Detailed design: of connections and interfaces with other components, such as cladding.

The architect and engineer work together at the concept design stage to ensure the architectural intent can be translated into a structure that functions to meet the primary requirements for strength, stability, robustness and durability mandated by building function, relevant regulation (usually the National Construction Code) and applicable Australian Standards. It's particularly important to establish stability considerations that dictate the location and extent of bracing elements as these elements may restrict the required functional attributes of the building.

The precise spatial arrangement of all elements must be defined at the detailed design stage. It may be necessary to modify the structural layout to accommodate interfaces with other components, such as services.


Services integration into composite steel floor slab. Courtesy enstruct

Key issues affecting steel frames

The following key issues may affect the structural design of the steel frame and should be addressed specifically:

  • The services-structure interface: as the detailed services layout is not generally known at the time when the structure is designed
  • The cladding interfaces: as the location of attachment points is unlikely to be known until the later stages of the design process
  • Detailing of the building envelope: this is increasingly important due to its effect on the thermal performance of the building. This includes cladding interfaces, roofing and infill walling
  • Location of the permanent and any temporary foundations: because tolerances may need to be agreed to suit the particular design solution.
Design aspects such as acoustic performance and vibration performance should also be reviewed.

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