Telegraph Hill Rock Slope Improvement Project: Construction Issues and Value Engineering Proposals

摘要

Telegraph Hill is a well-known topographic high located in San Francisco, California and topped by the Coit Tower landmark. The bay side of Telegraph Hill was historically quarried for rock material between the 1800's through early 1900's and was famously used as ballast for ships leaving the Golden Gate after unloading cargo. Situated within these old quarries is the Telegraph Hill project, which is comprised generally of greywacke sandstone and minor shale interbeds of the Franciscan Assemblage. The project location includes the steep exposed rock faces of these old quarry operations and is approximately 150 feet in height with an condominium complex at the toe of the slope that has been impacted by significant rockfall as recently as 2012. The rock slope improvement project follows numerous historic attempts to remediate the slope and includes rock scaling, installation of post-tensioned rock anchors, shotcrete, and a dual system pinned mesh system. This presentation discusses the construction issues related to the project as well as value engineering alternatives, including the use of passive dowel anchors and newly developed corrosion resistant elements, proposed for the project.