March 2018 Vol. 73 No. 3


Assessing Uncertainties in Geotechnical Baselines Reports

Editor’s Note: This is part three of an exclusive four-part series outlining the risks of modern underground utility infrastructure construction and rehabilitation work.

In Part 1, the concept of underground uncertainties in infrastructure work was introduced. In Part 2, we looked specifically at how contract language allocates the resolution of risks of underground uncertainties of existing conditions (geotechnical data, utilities, and constituents of concern) between the engineer, contractor and project owner. In this part, we will look at Geotechnical Baseline Reports that ideally bridge the results and interpretation of an investigation, and provide a contractual mechanism for clear assignment of relief for remaining differing geologic site conditions.

The 1974 National Academy of Science report Better Contracting for Underground Construction, is acknowledged as the basis for the concept of the geotechnical design summary report (GDSR), which transitioned into today’s geotechnical baseline report (GBR). In 1997, Geotechnical Baseline Reports for Construction-Recommended Guidelines was prepared by the Technical Committee on Geotechnical Reports of the Underground Technology Research Council, in order to standardize a practice that had been used in various forms for several previous years. Sponsored by the Construction Institute of ASCE and the American Institute of Mining, Metallurgical and Petroleum Engineers, this publication was updated in 2007.

The goal of the GBR is to “translate the results of geotechnical investigations and previous experience into clear descriptions of anticipated subsurface conditions upon which bidders may rely.” Baselines were intended to provide contractors with a mechanism that would not hold them responsible for unlimited risks involving unforeseen ground conditions. In that way, it’s a baseline for contractors to decide their methods of construction and level of risk they want to price into their bids. Ideally this would result in more realistic bids (both cost and schedule), and less time and effort in determining and pricing legitimate change orders.

Lower bid prices

The primary intended outcome of a well-developed GBR is lower bid prices, with a secondary intended outcome being a basis for addressing differing site conditions (DSCs). When a GBR is supported by a Dispute Review Board provision in the contract, resolution of DSC claims are arrived at much more quickly. Rarely are there legal or expert witness costs to establish a particular DSC. Overall, there is more cooperation to overcome a DSC claim and move the project forward.

Two challenges in preparing a GBR are determining which ground conditions should be baselined and how to quantify these baselines. Developing accurate or representative numerical baselines can be difficult, especially considering the variability of most geologic formations or the litter from a previous built environment. Ideally, a combination of extensive records or previous project research, geophysics, borings, local experience and a thorough site visit to look at the local geomorphology can lead to a good investigation that culminates in a GBR.

Contractors need to be very aware of how the GBR was developed: what is based upon fact, and what is based upon interpretations or opinion. Sometimes it is difficult to differentiate, and the consequences of not knowing might be detrimental to the bidding process. This non-differentiation of fact and opinion has led to justified criticism of the content of some GBRs.

Another criticism is that many times the subsurface conditions in a GBR are broadly portrayed to include low-probability/high-impact conditions. This reflects the owner’s desire to effectively eliminate the possibility for differing site condition claims. To achieve this end, owners influence the GBR professional to include a broad range of subsurface conditions in the GBR, some of which are very low probability of occurrence but that would have high cost impacts if they actually occurred. This influence dramatically compromises the primary intended purposes of the GBR – reduced bid prices.

If there is a widespread trend for GBRs to include low probability/high impact conditions as a part of the baseline in GBRs, it would be more equitable to all bidders to eliminate GBRs, and simply include the design geotechnical report and a differing site condition clause for subsurface information in the contract. Such a change would, in essence, return the contracting practice for subsurface conditions to a pre-1974 status. This would be a shame, since a GBR implemented consistent with the 1974 USNCTT recommendations is a well-tested process, and fair to all parties.

GBR evolution

It is now about 30 years into the use of GBRs in contract documents. There are still hiccups in their use. As with anything new, there have been attempts to interpret the guideline to favor one party or another. GBRs mix geotechnical and legal concepts, thus creating confusion. The gathering of the right data, the interpretation of the data and the determination of a reasonable baseline of what the contractor can expect in the preparation of its bid, is an extremely specialized area of practice.

Few members of the engineering community have experience writing, interpreting and administering GBRs. Few owners understand the concept of built-in processes for dealing with anticipated change orders, but are used to the concept of change order avoidance. Case law and information coming from Dispute Resolution Board determinations are starting to appear that will shape future development and use of GBRs. There are many documents available that highlight both success and failure of GBRs.

Some of the lessons learned in these past three decades are that GBRs should:

  • Have clearly written and measurable baselines
  • Fully explain non-factual baselines
  • Not use specifications for equipment or methods as baselines
  • Specify quality controls for measuring baselines
  • Recognize the wider implications of a failed baseline
  • Not have baselines so conservative as to circumvent owner responsibility for a DSC.
  • From these learnings, two prevailing traits exist in the projects that have successfully implemented GBRs:
  • The project owner is well-educated in the benefits and purposes of a GBR.
  • The GBR has been prepared by highly experienced persons specializing in such work.

From Geotechnical Baseline Reports – A Review: “Contractors have the right to expect that the baseline ground conditions presented in the GBR are reasonable. Ultraconservative baselines (i.e., attempts to shift unreasonable risk to the contractor) may not be successful, and this practice is discouraged because it may distort the bidding process and is contrary to the intent of the GBR. Owners have the right to expect that contractors will consider the full spectrum of baselined ground conditions when determining appropriate construction means and methods, and in preparing their bids. Furthermore, owners have the right to expect that Dispute Review Boards (DRBs) will evaluate differing site condition claims against the actual baselines presented in the GBR.”
GBRs are probably here to stay. They are also probably underutilized. The Engineers Joint Contract Documents Committee recommends GBRs be used on appropriate projects, and that the be developed  by a competent engineer. GBRs may not reduce uncertainties in a project, but they were developed to reduce the amount of bickering over those uncertainties when they are encountered.

Author’s note:
I have liberally used information given to me over the years by Dr. Ron Smith, Lester Bradshaw, Jr., Randy Essex, and Sam Baker, Esq. in the development of this article.

About the Author:
Jim Anspach is technical practice lead for Cardno Inc.’s Utility Engineering and Survey Practice. He serves as ASCE’s Utility Engineering and Surveying Institute president for 2018. He is the incoming chair for EJCDC, and chairs the ASCE 38 Standard Committee. He is also a member of ASCE’s Board Committee on Claims Reduction and Management.

Related Articles

From Archive


{{ error }}
{{ comment.comment.Name }} • {{ comment.timeAgo }}
{{ comment.comment.Text }}