On March 25, the Devil’s Slide Tunnels on Highway 1 in Pacifica, California opened to the public after five years of construction. These twin highway tunnels were constructed through San Pedro Mountain and bypass a section of Highway 1 that is prone to rock and mudslides. GZ provided IOST support services including the preparation of shop drawings, ground structure interaction analyses, evaluation of ground conditions in the field and the selection of ground support categories, as well as the evaluation of NATM instrumentation and results monitoring and the provision of senior advisory field staff.

For more information regarding the Devil’s Slide Tunnels, follow the link to the GZ project page.