The Design-Build Method (DBM) employed for the procurement of civil infrastructure projects of all types has, in recent years, seen increased usage in the US. This very much includes the underground infrastructure sector. While the DBM is growing in popularity, the jury is still out on whether it should be the procurement method of choice. The co-authors’ European experience indicates its own nuances in the underground industry’s continued search for innovative procurement methodologies, still leading toward the same principles of the DBM.
Against the backdrop of the increased use of the DBM and lack of any national standards and guidelines, different owners conceive and implement DB methodology in their own unique ways – with mixed results. The authors believe that it is high time that, based on an analytical analysis of the DB experience thus far, a “Road Map” of preferred practices be developed to assist the owners in selecting an appropriate approach when procuring their projects on the basis of the DBM.
Design-Build Method (DBM)
US underground infrastructure needs involve hundreds of billions of dollars of investment. For example, water/wastewater needs alone represent a US$1 trillion investment over the next 20 years according to the projections of the Congressional Budget Office and Water Infrastructure Network, the Environmental Protection Agency and others. Many in the industry think that this estimate is on the low side and that a significantly larger investment is needed. It is important that these large expenditures be made efficiently to maximise the return on the investment, and to ensure timely project delivery.
How underground infrastructure construction projects are procured is of paramount importance to ensure sensible cost and project delivery schedule requirements and to promote safety, quality and functionality of the underground facilities.
With the advent and rather widespread acceptance of the Design-Build Method (DBM) it seems that the civil-infrastructure delivery process, including underground infrastructure projects has come full circle. The DBM eliminates the chasm that developed over the past century between the design and construction sectors of the industry immediately following the golden age of the great master builders such as Brunel, Roebling, Eifle, etc.
The DBM promises to unify three key stakeholders, often confrontational under the traditional Design-Bid-Build Method (DBB), into a partnering posture. However this transition from DBB to DBM, even for above ground construction is not necessarily made easily, and becomes even more complicated when applied to the underground infrastructure project delivery process. Often it is not realised that underground construction project delivery, even under the tested and proven DBB approach, represents formidable challenges in terms of delivering the underground facility projects on time and within budget whilst meeting the project requirements in terms of safety and quality.
Much of the debate so far on DBM has focused on the shifting of the risk to the contractor and on legalistic aspects of the contract documents. The physical nature of the underground work, and the associated challenges with underground construction are not fully appreciated. The authors believe that it is not sufficient only to extrapolate the at-grade or above-ground infrastructure DBM experience to underground construction, and that the features of underground construction procurement process must be efficiently fused into the overall DBM procurement package.
There is a tendency now in the industry to view DBM as a silver bullet for solving all challenges associated with the delivery of civil infrastructure projects, including underground facilities. The trend to opt for DBM at the policy-level decision makers is on the rise. The benefits of DBM to their fullest extent are perceived to be: Quicker start of construction; quicker completion (time savings for earlier revenues); cost savings; single point of allocation of responsibility and minimisation of risk away from the owner and toward the Design-Build Team (DBT); and lesser management by the owner.
The authors’ experience indicates that while it is possible to achieve most and perhaps all of those benefits, a mere selection of DBM by itself does not guarantee success. Pitfalls can occur if an appropriate methodical approach is not used in the conceptualisation, preliminary design and preparation of the procurement documents, and during professional evaluation as well as the incorporation of risk management and quality assurance strategies. The discussion herein deliberately does not include project financing, and instead focuses on all other critical issues involved in the development and implementation of a DB Strategy (DBS) for the procurement of a specific underground infrastructure project. A definitive Design Build Road Map (DBRM) is provided for use by the owners and providers of underground infrastructure projects. DIG’s proposed Design Build Road Map (DBRM) is presented in the flow chart on page 35 (Figure 1). Brief explanations of the more significant items follow in the same order as the chart:
1 – Most owners do not necessarily have in-house design-build expertise. Hence it is important that an appropriate DB mind-set, with or without the involvement of an outside consultant, be established upfront as the first step in the procurement process.
2 – Project requirements together with project scope definition must be explicit and in plain language. The bidders should not have to perform complicated navigation between the plans, specifications and other contractual requirements to understand the programme scope. Explicit communication and clarity of the procurement objectives can prevent many pitfalls later.
3 – The authors’ experience indicates that the third-party interferences and associated costs are often not fully appreciated. This issue needs timely resolutions to avoid serious impacts on schedule and costs. However, admittance of a politological consultant with regard to project evaluation could be helpful for public acceptance.
4 – Cost estimates of underground infrastructure projects, if not computed accurately can kill the project in its tracks. Typically, the trend is for under-estimating the costs, sometimes by an unacceptable margin. Why there is such a major tendency for under estimating of construction costs is an issue in itself, suffice to say, that this issue needs close scrutiny in analysing the risk and in evaluating the bidders’ proposals. Its proper treatment requires input from experts in this field.
5 – Target schedule development must be based on a realistic basis and not wishful thinking.
6 & 7 – Underground Infrastructure preliminary design requires fully qualified and competent designers well versed in this highly specialised field who must be able to demonstrate their qualifications for the type of project under consideration.
The designer short-list selected for bid invitations needs to be compiled by individuals with sound knowledge of the design community, to filter out any accidental possibility of getting an unqualified designer on the bidders’ list.
The best potential bidders should be selected on the basis of their technical and professional merit and not the presumed competitiveness of their fee structures.
8 – Quantitative risk analysis should be a mandatory requirement in the authors’ opinion and should be performed by the preliminary designer upfront. A methodology is provided in the Figure 4 flow chart. This chart uses terminology and a sequence which should be familiar to professionals who perform risk analysis for such projects and hence it is not considered necessary to explain the procedure any further.
9 – The preliminary designer should be the entity who validates preliminary cost and schedule estimates with the participation of the owner’s design-build team.
10 – Tender development should follow a minimalist approach. Tendency to over design and over specify should be kept in check. Information overload is counterproductive to promoting competitive bidding.
Preliminary design included in the tender package must be capable of accommodating bidders’ expertise and means and methods and be capable of fully exploiting the benefits of Value Engineering options.
The design should be complete but not restrictive. The tender documents need to be based on an enlightened and equitable approach. All information must be disclosed and risks must be shared with the contractor on a fair basis. A detailed site characterisation is a prerequisite for a complete documentation of both the surface and sub-surface conditions as shown in Figure 2 (right) and Figure 3 (below).
11&12 – A Due-Diligence review of draft tender documents is a must, to ensure that the bid package meets the industry norms before the bid package is finalised. The “review panel” should include both design as well as construction experts. Remaining items in the DBRM are self-explanatory and hence do not need further explanation.
Conclusions
We recommend that owners consider all elements presented in the above DBRM and its subsets, while evaluating the suitability of DBM for procuring underground infrastructure assets.
Even with the more commonly used Design-Bid-Build (DBB) approach, underground construction entails many challenges not faced by the at-grade or above-ground construction. The DBRM proposed, is especially tailored to handle the underground construction environment. We believe, that DBM offers an excellent solution with a proper mind set, as reflected in the DBRM.
Historically too much emphasis has been placed on the legalistic aspects of shifting the risk to the DB consortium. The DBRM balances this approach, by recognising the uncertainties and the physical nature of underground constructions. There is no “free lunch” out there and eventually society pays for all costs associated with the project. An unfair shifting of the risk towards the DB consortium will only lead to drive more underground construction contractors out of business, limiting the competition and promoting unhealthy bidding environment, which in the short and the long term does not help the owners in promoting advanced technologies and in reducing construction costs of the underground assets their customers need.
Related Files
The sub-surface conditions should include a treatment of all four classes within the flow chart
Fig 3 – The geological/hydrological investigation and documentation should cover the three classes in the flow chart
Fig 4 – A quantitative design-build risk treatment strategy for underground infrastructure projects
DIG’s design-build road map (DBRM)
