When the City of Newport Beach began planning a new city hall, they intended to stay in the same location on the Newport peninsula. Not long into the project, the City faced the decision to select an alternative location.
City of Newport Beach
Newport Beach, CA
- Geotechnical Testing
- Environmental Assessment
Relocated from the Newport Peninsula, the City was able to include a 16-acre park with a dog park, civic lawn, wetlands, and extensive walking and viewing trails. The over sized rabbit sculptures are a favorite for social media posts.
The Leighton Solution.
Leighton performed a due-diligence level geotechnical investigation to assist the City and design team in development of an optimal project layout. Leighton subsequently provided geotechnical services during the design phase of the project and provided input during the plan review process. One of the project challenges was the requirement for extensive earth removal to assure that the City Hall building and parking structure stay below an approved “view plane” that protects the public’s view of the harbor and ocean from MacArthur Boulevard. Therefore, some of the key geotechnical challenges included analysis and design of proposed slopes and construction of a tall permanent shoring wall and multi-story parking structure requiring cuts of up to 40 feet located adjacent to a major street (MacArthur Blvd) with anticipated adverse geologic conditions. The permanent shoring wall required three levels of tieback anchors. Design of the anchors and wall system were influenced by adverse bedding conditions of the bedrock as indicated by our prior subsurface exploration of the site.
The project site is located in a seismically active area of southern California with the Newport Inglewood (Offshore) fault located less than 2½ miles from the site. To provide adequate uplift resistance to earthquake shaking, ground anchors were incorporated as a part of the foundation system for the City Hall building, Council Chambers and library expansion. Leighton worked closely with the structural engineer and provided geotechnical parameters for design of the ground anchors.
Leighton provided oversight during site grading and building construction. Geotechnical services provided during the rough grading phases included field mapping of exposed geologic conditions to confirm anticipated conditions and revised recommendations when conditions varied from those anticipated; geologic mapping during construction of the permanent shoring wall as well as observation and documentation during the installation of the tie-backs for the wall. Leighton also provided observation and testing during fill placement oversight during the installation and testing of ground anchors of the foundation system. Leighton has also provided geotechnical observation and testing services during the postgrading construction of infrastructure and other improvements.