News Detail

Defining Constructability

12/1/2023

In October, one of my PhD students successfully defended his dissertation. During the Q&A session, the issue of “constructability” came up and generated a lot of discussion. Because we only had academics at the table, I promised my colleagues that I would reach out to experts in the field. I sent a dozen emails, and I received more than I bargained for. I believe that this is a topic of interest to many, and I’m including excerpts from just four of the respondents. Before that, here’s the definition according to ACI Committee 134, Concrete Constructability:

“The effective and timely integration of concrete construction knowledge into the planning, design, and construction of a project to achieve the overall objectives with the goal of optimizing time, safety, and cost while maintaining the target level of quality.”

From Oscar Antommattei, Chief Concrete Engineer, Kiewit Corporation:

“…constructability strategies provide the ability to build work at a lower cost or faster schedule within the work performance criteria. It implies that the design must consider how the work can be built more easily and efficiently. To improve constructability, different designs, materials, schemes, means/methods, and processes for construction may be evaluated to facilitate the work while ensuring the work performance is within the expected cost, schedule, safety, and quality standards….The metrics are based on the impacts to cost and schedule, which is measured in terms of work productivity, while meeting the design intent and maintaining the safety and quality performance of the work.”

From Phil Diekemper, Senior Vice President, Ceco Concrete Construction (retired):

“...constructability can be considered a ‘fuzzy’ concept because there isn’t a formula or algorithm to achieve maximum constructability. The variables change from each project, location, and concrete contractor. There are basic constructability principles, such as repetitive member sizes and reinforcing, documents with the needed information to build, and coordination of tolerances, but the potential for gains goes much further….Too often, today’s structural designers and software aim to minimize material. They often achieve excellent results. Sadly, the constructability of such designs can be complex, time-consuming, and unproductive to build….The value for the owner is even greater than just the structural concrete cost as they too have time-dependent costs. These may include construction financing or delayed revenue streams by additional construction time.”

From Brett McMahon, Chief Executive Officer, Miller & Long Co. Inc.:

“…constructability in concrete construction is a balance between architectural vision, design intent, and overall simplicity of the formwork and the reinforcing….Construction is, in a sense, a type of manufacturing. Manufacturers concern themselves with shaving inefficiencies out of their assembly process. Assembly lines are designed to maximize repetition, which controls costs and minimizes errors. The greater the error-free output, the greater the ‘constructability’ of the product….The major difference between manufacturers and constructors is that builders have to recreate their assembly lines every day….There are many different aspects we review to try to maximize the outcome for the owner….Finally, an important aspect of constructability is the completeness of the design before and during construction. There is too much design delegation and too little control and coordination. Concrete often suffers from these situations.”

From Scott Anderson, Vice President and General Manager, Keystone Concrete:

“…in my opinion, constructability is a subjective matter. However, we can compare various schemes of design to optimize quantifiable parameters and determine the most ‘constructable’ scheme. That said, for any parameter considered, my conclusion of what is most constructable may differ from a general contractor’s or an owner’s. Therefore, I cannot provide specific metrics that I utilize to determine if a project is constructable. It requires experience and judgment. How much cost is too much if you alter the design? How safe is adequate? What schedule is fast enough and not worth additional premium costs or a potential reduction in safety? It is the combination of many items coupled with the experience of the team considering them that can make a project ‘constructable.’ The key is for involvement by all stakeholders to optimize the process. One potential change in the definition above is to strike the word ‘concrete.’ Sometimes the best solution for the project is not the optimal solution for concrete.…We must always stay relevant by considering allfactors of construction of projects.”

I hope that these opinions are of help. They certainly helped me and my university colleagues. In addition, readers are directed to an interesting article authored by Karlson et al. in the October 2018 issue of CI. Good reading!

Antonio Nanni

ACI President