#5 - Design-Bid-Build Method (Part -2)

Continued from #4 - Design-Bid-Build Method (Part -1)

Inconsistency, inaccuracy, and uncertainty in design make it difficult to fabricate materials offsite. As a result, most fabrication and construction must take place onsite, and only after exact conditioned are established. Onsite construction work is more costly, more time consuming, and prone to produce errors that would not occur if the work were performed in a factory where costs are lower and quality control is better.

Often during the construction phase, numerous changes are made to the design as a result of previously unknown errors and omissions, unanticipated site conditions, changes in material availabilities, questions about the design, new client requirements, and new technologies. These need to be resolved by the project team. For each change, a procedure is required to determine the cause, assign responsibility, evaluate time and cost implications, and address how the issue will be resolved. These changes and resolutions frequently lead to legal disputes, added costs, and delays.

In addition, the DBB process requires that the procurement of all materials be held until the owner approves the bid, which means that long lead time items may extend the project schedule. For this and other reasons, the DBB approach often takes longer than the DB approach.

The final phase is commissioning the building, which takes place after construction is finished. This involves testing the building systems to make sure they work properly. Depending on contract requirements, final drawings are then produced to reflect all as-built changes, and these are delivered to the owner along with all manuals for installed equipment. At this point, the DBB process is completed.

Because all of the information provided to the owner is conveyed in 2D (on paper or equivalent electronic files), the owner must put in a considerable amount of effort to relay all relevant information to the facility management team charged with maintaining and operating the building. The process is time-consuming, error-prone, and costly.

As a result of these problems, the DBB approach is probably not the most expeditious or cost-efficient approach to design and construction.

Next article, Design-Bid Method

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