Steel during design and construction stages

The construction procurement process for a steel building or structure is, in most cases, a straightforward and relatively linear process that can easily be synchronised with the architectural Plan of Work, especially during the early stages involving concept design and choice of structural form.

The use of steel, in its many forms, should be considered at the concept design stage. The decision to use steel is strongly dependent on the advantages it offers, including the ability to create architecturally interesting or long-span solutions, savings in the construction program and lighter weight leading to reduced loading on foundations and an ability to retrofit existing buildings.

In its simplest form, the procurement of a steel construction can be thought of as comprising the design process and the construction process in sequence. Ideally, however, the two processes should overlap to ensure the correct translation of architectural intent through the design process and into construction.

Structural design process

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.

Courtesy ARUP.

Refer to the design process page for more detail.

Structural steelwork specification

Various documentation is created during the design process, including drawings, 3D models and specifications. The ASI has created the National Structural Steelwork Specification (NSSS) to facilitate straightforward implementation of requirements from AS/NZS 5131 ‘Structural steelwork – Fabrication and erection’. This has been an initiative undertaken in collaboration with NATSPEC, whose documentation suite also now reflects the requirements of AS/NZS 5131. Download a free copy of the NSSS in Word or PDF format.

Construction process 

The construction process proper starts with design documentation that is the result of interaction between the architect and structural designer during the design process. The usual stakeholders in the construction process are:

• the main contractor: contracted by the client for provision of the complete facility
• the steelwork contractor: responsible for the provision of the steelwork component of the project
• the fabricator: responsible for fabrication of the structural steelwork utilising steel detail drawings provided by the steel detailer. May utilise computer numerically controlled (CNC) machinery with seamless input from the detailer's 3D software
• the steel detailer: responsible for translating the engineering design documentation into steel detail drawings, often utilising advanced 3D detailing software
• the steelwork erector: responsible for erecting the fabricated steelwork once it arrives on site from the fabrication shop or paint/galvanizing shop
• steel coating contractors: usually either painting or galvanizing to provide the required level of corrosion protection.

The usual stakeholder interactions during the construction process are illustrated in the schematic below:

The procurement process may be based on competitive tendering in which the key design information is made available to enable pricing by a range of steelwork contractors. For larger projects the steelwork contractor may be engaged in a two-stage design and construction process, in which Stage 1 enables the contractor to value engineer the solution prior to Stage 2, which is the construction package.