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Geotechnical Peer Review

Theodore von Rosenvinge, P.E., D.GE

Adding Value, Reducing Risk

Geotechnical peer review is not new, but it is not common industry practice. Today, however, there is a trend by public agencies in the United States to require it for tall buildings. What is geotechnical peer review, what is this trend, and what is its role in the design and construction industry for buildings and civil works?

News Flash!

August 21, 2017. The City of San Jose Office of the City Auditor issued a 52-page report to the City Council titled Audit of Residential High-Rises: Considerations for a City with a Growing Number of Tall Buildings. San Jose is the third largest city in California both in population and land area. Included in the report is the statement, “The City should consider additional safeguards to protect against geotechnical risk as taller buildings are developed.”

November 7, 2017. The City and County of San Francisco released Interim Guidelines and Procedures for Structural, Geotechnical, and Seismic Hazard Engineering Design Review for New Tall Buildings, where the “Structural Design Team shall include at least one Geotechnical Engineer” in all future projects.

January 2018. In New York City, discussions about geotechnical peer review begin with the New York City Department of Buildings and the American Council of Engineering Companies (ACEC) Metro Structural Codes Committee.

In the words of the song “For What It’s Worth” (written by Stephen Stills and first recorded by Buffalo Springfield in 1967), “there’s something happening here.” Is it one recent event or the culmination of issues? Population growth, seismic safety, concerns about effects of dewatering, and concerns about the settlement of buildings appear to have converged into a developing focus on geotechnical issues and geotechnical peer review.

Geotechnical Peer Review

Geotechnical peer review is not a new practice, but it is not the common practice. However, owners and designers are discovering the benefit of proactive peer review and the added value of managing risks to all parties associated with underground construction. There are several published examples of voluntary geotechnical peer review for some of the world’s tallest buildings.

Structural peer review is required by some building codes. For instance, it is well established in some jurisdictions including in New York City, Chicago, Los Angeles, Florida, Massachusetts, and Connecticut. Requirements (e.g., tall buildings or high-risk occupancy use) vary for when reviews are required. However, the geotechnical peer review component in these structural peer review requirements is generally absent.

The New York City (NYC) Building Code requires the structural peer reviewer to review the geotechnical report and confirm that the design incorporates the recommendations of the geotechnical investigation. The 2014 NYC Building Code Section 1617.5.1 states, “Review geotechnical and other engineering investigations that are related to the foundation and structural design and confirm that the design properly incorporates the results and recommendations of the investigations.” However, the NYC Building Code does not require an independent geotechnical engineer to review the geotechnical report, nor does it require the reviewer to confirm the validity of the recommendations in the report.

Are the San Jose recommendations and San Francisco directive the beginning of a national or perhaps a worldwide trend?

Agency Driven

Cities and states supplement adopted national building codes (e.g., International Building Code – IBC) with amendments and procedures to address local conditions, especially for tall buildings.

For tall buildings (240+ feet), the San Francisco Department of Building Inspection implemented amendments to its building code to include a geotechnical engineer as a member of the structural peer review team.

The city auditor of the City Council of San Jose seeks to adopt similar guidelines in response to an increasing number of proposed tall buildings. Some excerpts from the auditor’s guidelines report include:

Some jurisdictions have introduced voluntary peer-review programs. Effective January 2018, the City of Chicago, Illinois, has implemented an internal Structural peer review program through its Department of Buildings.

The Process

In the author’s experience, requests for geotechnical peer reviews often come in one or more of these contexts:

The peer review process can help all parties better understand, address, and ultimately reduce project risk. Naturally, the “reviewee” engineer or team can feel slightly uncomfortable by the prospect of an outside review. However, this can be mitigated with a positive attitude and a respectful, collaborative approach on the part of the reviewing engineer.

The best reviews actively and positively engage the design team to the benefit of all involved. Good peer reviewers possess both the required technical expertise (or know when, where, and how to bring it in), and strong communication and team-work skills.

Most peer reviews should take place during the design phase and start early, although a need for peer review can also develop from an unexpected construction issue. The review process may include inquiries about design procedures, analytical methods and results, and whether alternative solutions were considered. Commercial bid-ability and constructability may also be central topics.

The true purpose of a review is not to find fault or redo the work but to review the big picture and the processes, procedures, and rationale used during analysis and design. While the situation may dictate “audit level” technical or computational checking, the key is asking the right questions.

Questions may include:

Qualifications

A geotechnical peer reviewer should:

Geotechnical Peer Review Examples

The author has been involved with voluntary peer reviews as both the reviewer and the reviewee. A few brief examples are provided below:

The Future

Beyond guidelines presented in this article, published geotechnical peer review guidelines could be beneficial. However, each project is different and no cookbook can be developed to cover experience and engineering judgment. In 2004, the California Geotechnical Engineers Association (CGEA) published Recommended Practice, Peer Review Guidelines. This two-page document provides thoughtful guidance and key characteristics of a geotechnical peer review. Highlights include:

CGEA should be applauded for their proactive development and publication of these guidelines. Agencies cited above do not yet reference such guidelines. As is often the case, if the geotechnical profession is not proactive in developing such guidelines, others may. Institutional peer review requirements are continuing to evolve for both structural and geotechnical peer reviews and, as geotechnical peer review is closely related to structural engineering peer review processes already established in some venues, professional geotechnical organizations should take this opportunity to develop and disseminate such guidelines for practice.

In the meantime, owners, engineers, and agencies should embrace the trend towards geotechnical peer review. Appropriately used, a nominal investment in geotechnical peer review will add value and reduce risk for all parties.▪