Central Subway Construction Update 8/7/15

Thank you for your interest in the Central Subway Project, which is a significant project in the history of San Francisco's public transportation network. This project is the first underground line to link the north and south corridors of the city, and will provide a direct connection to major retail, sporting and cultural venues while efficiently transporting people to jobs, educational opportunities and other amenities throughout San Francisco.

This is an exciting time as the San Francisco Municipal Transportation Agency's | Central Subway team works to construct a vital transportation link that, when open in 2019, will improve connectivity for the city. Concrete has now been poured for the station roof slab on the east side of 4th Street Central Subway | Project Advancement

August 7 - August 17, 2015

This notice provides a construction update and a look ahead for what to expect in the areas where we are building four new stations along the alignment. You’ll find information about work activities, traffic and transportation impacts taking place over the next two weeks at SoMa, Yerba Buena|Moscone, Union Square and Chinatown.

Construction schedules, bus routes, and stop locations are subject to change due to unforeseen conditions. Signs will be posted at affected stops to advise of service changes.

Our thanks go out to the businesses, residents, shoppers, commuters, and all those who are touched by the Project, for their continued engagement as we work to extend the city's public transportation system.

The Central Subway Team

Sewer upgrades and other utility work underway at 4th and King Streets  Surface Station, Trackwork and Systems For the work along 4th Street between Bryant and King streets, a surface station located between Bryant and Brannan Streets will be built. Besides construction of the surface station, the only visible construction activities will be upgrading utilities and trackwork on 4th Street between the portal at Bryant and the connection with the existing system at King Street.

Major construction activities will occur at the 4th and King streets intersection, where special trackwork will be installed to connect the existing and new rail systems. The first phase of construction is scheduled for Labor Day weekend September 4 - 8 with vehicle traffic detoured during that time.

Current activities include utilities relocation, Muni manhole, and duct bank installation.

The contractor is performing work on the 36' sewer line and installation of the existing high pressure water line at the 4th and King streets intersection between the hours of 9a.m.- 3p.m. No through-traffic on King Street to I-280 until August 14.

Installation of domestic and high pressure water lines on 4th street between Bryant and Freelon streets continues through August 21.  A welder works with a section of sewer pipe at 4th and Welsh
  Workers lowering steel sheets on 4th north of Welsh Overview

• Installation of Muni manhole and duct bank
• Utility installation
• 36' sewer line and removal of high pressure water line

Details

What: Installation of Muni manhole, duct bank, and utility installation
Time: 7a.m.-4p.m.
When: Monday to Friday
Where: Bryant to Welsh, Brannan between 4th and 5th

What: 36' sewer line and installation of high pressure water line
Time: 9a.m.-3p.m.
When: Monday to Friday
Where: Intersection at 4th and King
  What to expect

• Work may involve saw-cutting, potholing and jack-hammering on the roadway and sidewalk
• Sidewalk access may be limited
• The contractor will maintain a safe path of travel as well as access to businesses during business hours
• Parking and Traffic Impact
  • Parking will be unavailable along the work area
  • Two lanes on 4th Street between Bryant and King streets are available for traffic
  • Intersection of 3rd and King closed to traffic and pedestrians

Temporary steel supports have been added to the walls of the station headhouse as excavation progressed Yerba Buena | Moscone Station

4th Street from Howard to Folsom

Work along 4th Street between Howard and Folsom streets consists of construction of the underground Yerba Buena | Moscone Station. The cut and cover method known as a "top-down" or "bottom-up" approach involves construction of a box frame structure within a trench excavation that is subsequently backfilled.

Current activities include excavation, roof deck installation, and utility relocation.

Temporary steel supports have been installed for excavation Excavation of the station entrance is underway Overview

• Installation of utilities
• Excavation and installation of the roof deck

Details

What: Excavation and roof deck installation
Time: 7a.m.-7p.m.
When: Monday to Friday
Where: Howard to Folsom

What: Utility night work
Time: Folsom Street work begins at 9p.m.-5a.m.; Howard Street work begins 6p.m.-5a.m.
When: Monday to Friday
Where: 4th and Folsom and 4th and Howard What to expect

• Clementina Street is closed at 4th Street
• The sidewalk on the west side of 4th Street is closed
• Parking and Traffic Impact
  • One lane will be available on the west side of 4th Street
  • Two right lanes on Folsom Street available during night work

Worker sprays water to keep dust at a minimum during jack-hammering of the floor slab Union Square | Market Street Station

For the duration of the project, you'll see work along Stockton Street between Ellis and Post streets. The construction of an underground Union Square|Market Street Station uses the cut and cover method known as a "top-down" or "bottom-up" approach involves construction of a box frame structure within a trench excavation that is subsequently backfilled.

Current activities include roof deck installation, demolition of the northwest corner of the Union Square Garage, utility relocation, compensation, jet grouting and sheet pile installation.

Single-lane continues through early October on Geary at Stockton for pile installation.

An excavated planter on the west side of Stockton north of Geary reveals a drainage pipe Steel cables extending beyond the south exterior wall of the Union Square Garage mark where tiebacks have been installed Overview

• Sheet pile installation
• Installation of roof deck
• Utility relocation and support
• Excavation
• Compensation and jet grouting
• Partial demolition of Union Square Garage
• Rebar installation

Details

What: Pile installation, roof deck, utility, excavation, compensation and jet grouting, rebar installation and partial demolition of Union Square Garage
Time: 7a.m.-11p.m.
When: Monday to Saturday
Where: Ellis to Post
* Construction hours may be 24 hours a day, Monday to Saturday, Sunday work may be required What to expect

• Local deliveries may access Maiden Lane from Post Street
• Sidewalk access may be limited at times
• Muni Service Impact
  • The bus stop for the 38 Geary Route on Geary Boulevard at Stockton Street is discontinued until further notice. Board bus on Geary Boulevard at Powell Street.
• Parking and Traffic Impact
  • Ellis Street is closed to through traffic between Stockton and mid-block until late September
  • Stockton Street between Ellis and Post streets is closed to vehicular traffic

These temporary steel supports are installed inside the station headhouse Chinatown Station The construction of an underground Chinatown Station uses the sequential excavation method (SEM) along Washington and Stockton Streets. The SEM provides a high degree of flexibility during construction and makes it possible to control virtually all kinds of ground conditions, thereby greatly reducing the risks of construction. This method of tunnel construction is used worldwide for small to large openings in a variety of ground types ranging from rock to soil.

Sprayed concrete (shotcrete) and other supporting elements immediately after exposure, followed by installation of additional steel and shotcrete support elements until a safe stable opening is created will be used.

Current activities include utility relocation, excavation of the headhouse, and dewatering wells.

Dewatering wells installation on Stockton Street from Sacramento to Washington streets continues through October. During work hours the mid-block bus stop on the east side of Stockton Street between Sacramento and Clay streets will be relocated just north of Clay Street. Work to excavate the Chinatown Station headhouse is ongoing Light shines into the headhouse interior from an access shaft on Washington just west of Stockton Overview

• PG&E reconstructing underground utilities
• Excavation of station site
• Installation of dewatering wells

Details

What: PG&E activity
Time: 9a.m. to 3p.m. and 7a.m. to 6p.m.
When: Monday to Friday and Saturday
Where: Washington to Jackson

What: Excavation of station site
Time: 7a.m.to 7p.m.
When: Monday to Saturday
Where: Stockton and Washington

What: Dewatering wells installation
Time: 9p.m. to 5a.m.
When: Monday to Friday
Where: Sacramento to Washington What to expect

• Sidewalk access may be limited at times
• Muni Service Impact
  • A mid-block bus stop on the east side of Stockton Street between Sacramento and Clay will be relocated just north of Clay
• Parking and Traffic Impact
  • Detour will be in place between the hours of 9p.m. to 5a.m. during dewatering wells installation
  • Parking will be unavailable during PG&E work
  • Washington Street:
    • remains closed between Stockton and Trenton streets
    • is converted into a two-way street between Powell Street and the construction zone

Connecting People. Connecting Communities.

Contact Us: If you have questions about construction or the Central Subway Project you can email us at central.subway@sfmta.com or call us at 415-701-4371.

For More Information: The Central Subway team posts frequent project updates on a variety of social media outlets. To find out more about the project and construction progress, follow us on Facebook, Twitter, or Flickr, and check out our blog.

Construction schedules are subject to change.