Tuesday - October 13, 2026

 6:00 p.m. to 8:00 p.m. PDT

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"Engineering Geology and Building of the Skywalk, Grand Cayon West"

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By: John Peck

Consulting Geologist, Las Vegas.

Former President of AEG and Former Chair of Southern Nevada Chapter

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Abstract:​

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The Skywalk at the west rim of Grand Canyon is built on two steel cantilevered box beams that extend seventy feet beyond the canyon rim.  The glass-bottomed walkway is located on the Hualapai Indian Reservation in Mojave County, Arizona.  A glass floor and glass sides allow visitors to view the canyon’s depth of 4000 feet, the Colorado River and the surrounding Grand Canyon cliffs without obstruction.  The horseshoe-shaped beams are positioned on four piers composed of sets of twenty-two 2.5-inch threaded steel micropiles drilled and grouted 45 feet into the Pennsylvanian to Mississippian age Callville Limestone and incorporated in massive concrete caps.  The piers near the cliff at the canyon’s edge also have three 40-foot steel tiebacks drilled and grouted at 30 degrees below horizontal away from the direction of the cliff face.  A rock bolt scheme was devised to further stabilize a wedge of rock near the southeast pier because of intersecting rock joints that produced a wedge failure about 35 feet below the cliff top in the past.

The site investigation included surface mapping, core drilling and testing, helicopter inspection of the canyon walls and close inspection of the cliff face using a man cage suspended from a crane at the surface.  Rock structure at the initial proposed location at Eagle Point was considered unsuitable because of the open condition and unfavorable orientation of joints in the Callville.  One open joint was 125 feet long and was open as much as 2 ½ feet at the surface.  The site was moved about 100 yards further north along the cliff to a more stable part without open fractures.

The program will consist of a video produced for National Geographic Channel describing the investigation and building of the Skywalk.

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​​​​​​​​​​​​​​​​​​​​BIO:

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Mr. Peck has 53 years of experience in geology, geotechnical field operations, nuclear waste management, and field office management and administration.  During this time he managed field projects funded by the U.S. Department of Energy (DOE) and private industry; provided technical direction and integration of projects related to the siting and licensing of nuclear facilities, mined geologic waste disposal, and large engineered facilities including rock tunnels.  From 1977 to 1997, he was a technical leader in DOE high level nuclear waste management programs, including the Salina salt basin characterization, the Permian Basin area characterization and site selection, Technical and Field Services Contract for the Deaf Smith County Texas Repository Site, and Geotechnical Operations for the Yucca Mountain Site Characterization Project (YMP).  In addition, his assignments have included expert testimony on behalf of license applicants for nuclear power facilities, regional tectonic analyses, production of technical licensing documents, direction of field mapping projects, and field office management. He is a specialist in geology of evaporite deposits and their engineering properties in relation to siting of surface and underground facilities.  He has published more than 40 technical papers.  He served as President of the Association of Engineering Geologists in 1997-1998.

Since 1997, Mr. Peck has been a consulting geologist.

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