ERECTING STRUCTURAL STEELWORK

The erection of structural steelwork consists of the assembly of steel components into a frame on site. The components are then lifted and placed into position before they are connected together. Generally, connection is achieved through bolting but, in some cases, site welding is used. The assembled frame needs to be aligned to within tolerance expectations (usually defined in our Standards) before final bolting up is completed. The completed steel frame may then be handed over for further work on internal floors, external cladding and mechanical and electrical fitments.

Design for construction

The successful construction (including erection) of steel structures safely, quickly and economically starts long before the actual steelwork arrives on site from the fabrication shop. The buildability of the structure is influenced significantly by decisions made during the design process long before erection commences.

It is important that designers clearly understand the impact of their decisions. Design for construction is a valid design objective and one that should be considered along with the other usual design objectives in play.

Four design factors to consider in relation to buildability are:

• Repetition and standardisation: repetition of the same structural components and common/standard details for connections.
• Achievable tolerances: if tight tolerances are specified (i.e. more restrictive than Class 1 in AS/NZS 5131) then special controls will be needed and possibly specially engineered details.
• Frame type: the primary choice is between braced frames and continuous frames.
• Floor systems: for multi-storey frames, the choice of floor system will affect the erection sequence as it determines the stability of the part-erected structure.

Erection planning

Planning for erection should start at the very beginning of the design process. Such planning should consider the construction sequence, the design factors that affect buildability and site practice in terms of typical erection plant.

In the broader design and planning context, there are three planning factors that affect the buildability of steel structures:

• Practical erection sequence: the location of both temporary and permanent bracing systems or other means of maintaining structural equilibrium are crucial here.
• Simplicity of assembly: simply assembled connections are the main factor here.
• Logical trade sequences: which will affect the development of the master contract programme as the pre-tender plan metamorphoses into the construction plan.