Geotechnical Reports as Contract Documents?

Bart Miller, P.E.

There are various methods for incorporating the recommendations of Geotechnical Reports into structural drawings and specifications, and for engaging the Geotechnical Engineer in the design process. Invariably, Structural Engineers extract pertinent design and construction information from Geotechnical Reports to use as the basis for foundation-related design and detailing directives included in contract documents.

Often, Geotechnical Reports are provided to the contractor as a reference document. Structural Engineers may also request or require the Geotechnical Engineer to review structural drawings and specifications to confirm the correct interpretation of geotechnical recommendations. In some areas, Geotechnical Engineers even provide signed and sealed specifications, usually for earthwork, piers, piles, etc., to be included with the contract documents. However, under no circumstances should Structural Engineers specify the Geotechnical Report itself to be a contract document.

Some argue that specifying Geotechnical Reports as contract documents creates the following perceived benefits:

The first two “benefits” wrongly assume that the Geotechnical Engineer is not responsible for his/her work if the report is not a contract document, or that the Structural Engineer will be held directly responsible for precisely following recommendations from a Geotechnical Report. Neither is correct under normal circumstances. The Structural Engineer does not assume responsibility for the soil-related aspects of the foundation design by merely transferring Geotechnical Report recommendations into the contract documents. Similarly, specifying the Geotechnical Report as a contract document does not assign additional responsibility to the Geotechnical Engineer for their own engineering work.

The Geotechnical Engineer is responsible for the soil-related recommendations used in the design of the building foundation. If those recommendations are later deemed not to meet the Standard of Care, as defined by what other Geotechnical Engineers would recommend in the same situation with the same data, then the Geotechnical Engineer is held to the same standard for the soil-related design recommendations as Structural Engineers are for the structural design of the foundations.

The second two “benefits,” while true to a degree, are insignificant compared to the very substantial risks the Structural Engineer may assume as a result. Saving a small amount of time during the design phase, or circumventing the responsibility for careful interpretation, does not offset the potential consequences.

Geotechnical Reports, along with other consultant reports such as wind tunnel reports, snow and ice studies, etc., should never be specified as contract documents. Consider the following:

Structural Engineers should reference Geotechnical Reports in structural drawings, commonly in the general notes or design criteria documents, to identify the source of information included in the contract documents pertinent to the foundation design. These reports should be made available to the construction teams as reference documents, but not contract documents. Structural Engineers should clearly indicate on the contract documents that the design team is not responsible or liable for the accuracy of the information presented in the Geotechnical Report, as is consistent with established legal precedent and the Standard of Care.

Structural Engineers are responsible for interpreting various consultant reports and then specifying precise design and construction requirements. Perhaps no consultant report is more prone to misinterpretation leading to construction claims than the Geotechnical Report.

Because the contractor is only bound to information included in the contract documents, Structural Engineers must recognize the importance of reading Geotechnical Reports completely and carefully, and editing structural drawings and specifications to match. Many Structural Engineers start with “typical” details and boiler-plate specifications encompassing information for a variety of soil types and ground conditions that require vigilant editing to be consistent with soil conditions defined in the Geotechnical Report. Without proper editing, not only will the contract documents not reflect the appropriate soil conditions and requirements for the project, but the Structural Engineer may become liable for the content in the structural drawings and specifications that does not meet Geotechnical recommendations.

Structural Engineers should consider requesting or even requiring the Geotechnical Engineer to review and comment on the structural drawings and specifications as they pertain to site preparation, foundation systems, and slabs on grade. In general, early and consistent communication with the Geotechnical Engineer will ensure the proper interpretation of the Geotechnical Report and improve the overall documentation of the foundation design.▪