Worker demonstrates soil test drilling at news conference held in Westwood on Aug. 20, 2009. The exploratory drillings are a key part of the planning and environmental process for the proposed Westside Subway Extension, a regionally beneficial Measure R transportation project. Photo by Gary Leonard

The next step for planning and engineering the Westside Subway Extension — including deciding the exact route the project will ultimately take through Beverly Hills, Century City and Westwood — begins next week when Metro contractors begin conducting soil, seismic, noise and vibration tests as part of final environmental review and preliminary engineering for the project.

In October, the Metro Board of Directors approved two Century City station locations for final review, resulting in two alignment options between that location and Beverly Hills.

One route option has raised the ire of some in Beverly Hills because it would travel underneath historic Beverly Hills High School to reach a station at Constellation and Avenue of the Stars. The other route option would stay largely under city streets to reach a station at Santa Monica Boulevard and Avenue of the Stars. That route is not without its concerns as well – it would follow a known earthquake fault. For a summary of these and other options, read a previous Source post.

Geotechnical work will be conducted along the entire planned alignment from Western Avenue to the Westwood/VA Hospital but will begin in the Beverly Hills, Century City and Westwood areas to help resolve this outstanding issue. Next week’s testing is scheduled for Westwood, where work permits have been secured.

The mini-vib truck used to do seismic and soil testing.

The project team is working with the cities of Los Angeles and Beverly Hills to do the work on city streets. They are also working with the Los Angeles Country Club to gain access for some testing at the golf course. Metro staff have also contacted the Beverly Hills Unified School District to request conducting tests at Beverly Hills High School during the holiday break to avoid affecting students.

Geotechnical work will build on the data gathered during the previous draft environmental review phase. In April of 2009, Metro completed some initial exploratory drilling at approximately 70 Westside sites. These new tests will provide the project team with additional soil and seismic information that is needed to narrow the route down to one in these areas.

Some of the planned geotechnical work includes:

• Seismic testing conducted using a “Mini-Vib” truck and a hand-held “Micro-Vib” box. These machines create vibrations on the surface which are read by sensors.
• Different types of borings to obtain soil samples for testing and evaluation.
• Noise and vibration testing will be conducted along with some of the borings.  At these locations, a vibration will be created down in the bore hole and measured at sensors on the surface at that location and in or adjacent to nearby buildings.

In many cases the work will occur during the day, but some work will need to be conducted at night.

Over the next two to three months, tests will be performed at more than 200 locations on the Westside. Depending on what the data shows, additional testing may be needed.

Details of when and where work will occur, what to expect, any impacts, and contact information will be distributed to residents and businesses closest to the testing locations in advance. It will also be distributed electronically to key organizations in those areas and posted on Metro’s website.  Local residents and motorists should anticipate some impacts, including possible lane closures, which are unavoidable so that that the team can gather the best data possible.

Overall, the geotechnical data gathered from the tests will be used to make recommendations about the best, safest and most effective ways to design and build the subway.

Metro expects to finish the final environmental review stage of the project in the next year, but plans to keep the public updated every step of the way in this, the last phase of environmental work prior to construction.