Abstract:
This paper highlights a construction project which encountered multiple schedule delays and foundation construction sites where actual geotechnical conditions encountered during construction differed from those anticipated during the bid phase and detailed design. These foundations were constructed using helicopter access to support high-voltage transmission line structures across extremely steep terrain in Northern California.
During the bid phase, site-specific geotechnical data was unavailable. Instead, a desktop study was used to develop assumed subsurface conditions, with shallow bedrock presumed for design purposes. However, during construction, bedrock was not encountered at multiple construction sites. The schedule delays and unexpected change of conditions required the contractor to adjust resources and develop alternative foundation designs and construction methods to adapt to the actual conditions and maintain the project schedule.