Single-Family Homes
3003 Dwight Way – Berkeley, CA
Geotechnical Investigation
AKA conducted a geotechnical investigation and provided geotechnical engineering services during the upgrade of an existing residence in the Berkeley hills. The property is located within the Alquist Priolo (AP) Special Studies Zone for potential fault rupture hazards associated with the Hayward Fault, as well as within a Seismic Hazard Zone (SHZ) for potential earthquake-induced landslide hazards.
Completed in 2023, the project involved a 4,200-square-foot (ft²) addition, plus a 910 ft² 3-car garage, to an existing 3,275 ft² single-family home. The addition included a new master bedroom suite, an enlarged kitchen, a new formal dining room, a new music room and music library, and a new book library and meditation space. Exterior improvements included a carport/storage area, view terrace, site retaining walls and walkways/stairs, and rehabilitation of the existing driveway off of Dwight Way that provides access to the property.
Proposed future site improvements on the upper portion of the property consist of a swimming pool, pool house, outdoor kitchen, green house, solar and thermal arrays, site retaining walls, and walkways/stairs.
3913 Happy Valley Road – Lafayette, CA
Geotechnical Investigation
AKA conducted a geotechnical investigation and is providing geotechnical engineering services during construction of an upscale residence in the Happy Valley area of Lafayette. Completed in 2022, the first phase of the project consisted of the demolition of the existing residence and carport on the upper building pad of the property and the demolition of the existing swimming pool and associated yard improvements on the lower building pad of the property. Site grading consisted of the reconfiguration of the private driveway to allow fire truck access to the residence, backfill of the excavation created by the demolition of the pool, and removal and re-compaction of the existing fill material on the lower building pad. New improvement constructed on the upper building pad consisted of a 5,900-square-foot (ft²) residence with attached garage, outdoor kitchen, zen garden, play yard, new site and driveway retaining walls, and a permeable paver parking area.
Proposed improvement to be constructed on the lower pad during the second phase of the project consists of a 1,100 ft2 accessory dwelling unit, a 500 ft2 covered loggia, a swimming pool, exterior walkways/patios, and a new access driveway.
Re-Building After a Disaster – San Bruno, CA
Geotechnical Investigation
Construction Observation and Testing Services
AKA is proud to have been part of the rebuilding effort after a natural gas pipeline explosion and fire devastated a quiet residential neighborhood in San Bruno, California. AKA conducted a geotechnical investigation for reconstruction of one of the many homes that were destroyed by the explosion and fire that occurred on September 9, 2010. Old foundations were removed from the site, exploratory borings were drilled, plans were developed, and a new home was built. AKA was also busy in the neighborhood assisting in an insurance claim evaluation involving one of the many still standing homes in the explosion and fire impacted area.
Broadway Terrace – Oakland, CA
Landslide Investigation
Construction Observation during Landslide Repair
Geotechnical Investigations for New Homes
Construction Observation during New Home Construction
In the early 1950s, a major landslide destroyed several homes built along Broadway Terrace in the Oakland Hills. Due to the significant challenges of repairing a major slide that is closely bordered above and below by city streets, and on each side by existing homes, the site remained dormant for almost 50 years. AKA conducted an extensive program of site characterization and developed recommendations for repair of the slide. In addition, AKA subsequently monitored the repair. With detailed knowledge of the slide and underlying bedrock characteristics, the repair contractor was able to successfully implement a slide repair that incorporated temporary shoring to protect adjacent improvements and phased excavation and replacement of the landslide material. AKA subsequently performed the investigations for four new homes and is currently monitoring the construction.
1215 Oxford Street – Berkeley, CA
Geotechnical Investigation
Construction Observation and Testing Services
1215 Oxford Street is a single-family residence located in the geologically complex landslide environment of the North Berkeley Hills. The site is located within what is locally known as the Keith Avenue Landslide, which is a massive deep-seated and actively creeping landslide complex with average dimensions on the order of 3,000 feet long by 1,300 feet wide that underlies a densely developed residential area. AKA has an extensive history of investigating the characteristics of the actively creeping slide zones in the North Berkeley Hills and has provided recommendations for numerous successful residential projects throughout the area. As is the case with 1215 Oxford Street, AKA typically recommends support of structures in this type of environment on a mat or raft foundation that is designed to move akin to a raft on the water as the underlying ground continues its inevitable slow downhill creep.
Berkeley Hills Residence – Berkeley, CA
Geotechnical Investigation
Construction Observation and Testing Services
This residence was constructed in an area identified as an active but slow-moving landslide in the Berkeley Hills. A special mat foundation design was developed by AKA to accommodate ground movements. In addition, measures were taken to keep a rural feel to the site while properly collecting and discharging the surface water. AKA monitored the construction of these facilities.
25255 Mount Bache Road – Los Gatos, CA
Foundation Investigation
Construction Observation and Testing
25255 Mount Bache Road is a single-family residence located in the Santa Cruz Mountains. The property is located in close proximity to the San Andreas fault and is also located near the epicenter of the 1989 Loma Prieta Earthquake. A geologic hazard evaluation conducted at the property in 1997 by Nolan Associates (NA) identified the potential for ground cracks up to 3 inches wide with one inch of vertical offset passing anywhere through the building envelope. Given the hillside environment, we would normally recommend drilled pier foundations for support of the residence, with piers extending into site bedrock. However, a drilled pier foundation would not have been compatible with the need to design the foundation system to resist the potential for ground cracking as identified by NA. Therefore, in order to minimize the potential detrimental effect on the house foundations due to potential horizontal and vertical offset cracking as indicated by NA, we recommended the house be constructed on a rigid mat foundation. The intent of the rigid mat is to provide a foundation system that can span local irregularities and act as more of a unit, in case ground cracking occurs. We also recommended the mat foundation be underlain by a minimum of 4 feet of geo-grid reinforced, compacted engineered fill in order to help spread out the potential surface expression of ground cracking directly below the mat foundation. It is noted that the design concept of a rigid mat overlying a geo-grid reinforced fill in order to limit effects from potential ground cracking has been documented by Bray (2001).
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