9.2.1 Design-Bid and Build (DB&B)

Categories: 9.2 Procurement Alternatives
Time of issue: 2022-04-28 10:18:10
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Description:

Information

The design-bid-build (DBB) is the most traditional method of construction procurement and is well established and recognized. With this approach, the client establishes separate contractual relationships with the design team and the contractor. It is a linear process where one task follows completion of another with no overlap.

Process

Design Phase – A design agency is commissioned by the client to prepare project construction documents, including specification and construction drawings. The designer is responsible to design to the professional standard of care. For rural wastewater projects, the design engineer will work with the client and local villagers to evaluate site conditions and develop preliminary designs and or alternative plans for the client and village leaders to review. Once the preliminary plans are approved, the engineer will prepare the complete documents. These documents are then coordinated by the client and design engineer for competitive bids.

Bid Phase – General contractors are asked to submit their bids in accordance with the design documents. The client and design engineer will rank the bids based on various criteria, such as qualifications, experience, references, and quotations. If the qualifications of potential contractors are acceptable to the client, the contract will be awarded to the lowest bidder.

Construction Phase – After contract awarding, the contractor will follow the requirements in the design documents to carry out construction works. The design engineer routinely acts as the client's agent to review the progress of the work, to issue site instructions, change orders and/or other documentation necessary to the construction process.

Advantages

Scheduling of DBB approach is straightforward since design and construction happen sequentially without overlapping. The linear process is easy for the client to manage.
The design team acts on behalf of the client, rather than sharing an interest with the contractor. Therefore, the design professionals have an incentive to design a quality building and oversee that their design requirements get implemented during construction.
The contractors’ estimates can be more accurate, as when they bid for the project the design documents are well developed.
The design team becomes more active in the construction administration role, which allows more clarity in the contractor’s interpretation of the design requirements, and better overall achievement of the owner’s design intentions.

Disadvantages

As the DBB process is linear, a delay in one phase will set back the entire project progress.
The contractor does not have the chance to offer input to project design. Therefore, important design decisions affecting the types of materials specified and the means and methods of construction may be made without appropriate consideration from a construction perspective.
If bids run over budget, redesign, value engineering, and rebidding processes can lead to project delays and additional design costs.
The client is potentially vulnerable to change orders, delays, and additional costs initiated by the contractor.
Designers and contractors bear no contractual obligation to one another and the client bears all risk associated with the completeness of the design documents.
Development of a "cheaper is better" mentality amongst the general contractors bidding the project, so there is the tendency to seek out the lowest cost sub-contractors in a given market. In strong markets, general contractors will be able to be selective about which projects to bid, but in lean times, the desire for work usually forces the low bidder of each trade to be selected. This usually results in increased risk (for the general contractor) but can also compromise the quality of construction. In the extreme, it can lead to serious disputes involving quality of the final product, or bankruptcy of a sub-contractor who may have under-bid the project but was on the brink of insolvency and desperate for work.
Adversarial relationships and potential for litigation can develop between design engineer and contractor, due to their separate contracts with the client.