Ithuta JV

Source - Article by Bob Andrew

The concept of ‘constructability’ is well known in construction project management. A constructability review is applied during the project feasibility stage, as well as during other stages of the project, to identify construction obstacles and risks in order to prevent mistakes and avoid time and cost overruns.

Constructability reviews are not new. It is said that Hamid, a ‘construction manager’ for the Great Pyramid of Geza project complained to the Pharaoh that the design and quality of the building blocks he was receiving were not conducive to easy construction as they needed too big a labour force, were causing unsafe work practices and putting them in place was taking too long. The Pharaoh, as a result of these complaints, arranged for Hamid to sit down with the block designers and the block suppliers to ensure that the right size of block, of better quality, was produced. Hamid’s constructability reviews must have paid off as research on the design of the pyramids has shown that they are not just a collection of heavy rocks with unknown structures, but incredibly precision-built structures.

Constructability issues generally involve topics like, ‘buildability’, sequence of construction activities and system integration, but should also include materials of construction issues, such as procurement, delivery, storage, preparation, construction and finishing of the materials being used.

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The selection of suitable materials of construction can be a painstaking process. The properties of the candidate materials have to be assessed against all mechanical, physical, chemical, environmental, safety, maintenance and production requirements, as well as the material’s constructability or fabricability for the given project applications. In particular, the material’s cost-effective durability and reliability properties, relative to any corrosion that will take place in the short and longer terms, must be evaluated. Once this evaluation is complete, a suitable material is selected, to be used either on its own or in conjunction with applied corrosion protection.

The manner in which the material is used in construction can often have severe implications on the material’s reliability and durability expectations. Examples of this are re-passivation of chromium-nickel steels (stainless steels) after fabrication, avoiding welding on internally rubber-lined steel vessels and the repair of mechanical damage in paint coatings on steel. Failure to re-passivate stainless steels, welding on rubber-lined vessels and ignoring damaged paint coatings, as examples, will render these materials largely dysfunctional during service. The recognition of how corrosion resistant properties of a metal can be affected by construction is indeed a major constructability issue, which, regrettably is often ignored.

While the benefits of constructability reviews are recognised, there are barriers to addressing constructability that often prevent project optimisation. A lack of construction experience in the design team and lack of standard procedures and processes to address constructability are often seen as major barriers. A failure or inability to adequately recognise the role of materials during construction is also believed to be a major barrier.