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Central Subway Construction Update 11/6/15

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. Workers prepare to weld rounding copper to the tracks using a rapidly burning powder Central Subway | Project Advancement

November 6- November 16, 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 goes 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

New tracks join tracks  already embedded in the street, leading to the N Judah platform Surface Station, Trackwork and Systems For the work along 4th Street between Bryant and King streets, a surface station will be built between Bryant and Brannan Streets. The construction team is working on upgrading utilities and trackwork on 4th Street between the portal at Bryant Street and the connection with the existing system at King Street.

Over the past week, the team worked hard and successfully completed the 24 hour operation at 4th and King. You will now see a new track configuration including tracks headed down 4th Street which is the beginning of the tracks for the Central Subway.   Future track installation along 4th Street will take place after utility relocation is work is complete.   Thank you for working with us as we build a better transit system for the City.

Current activities include utilities relocation, Muni manhole, duct bank, water line work from the water department, auxiliary water supply system, and sewer structure modification work. A worker makes markings at a junction where N Judah tracks cross the future T line tracks going north on 4th Street
  Many community ambassadors were stationed at the intersection of 4th and King and affected transit stops to inform the public how to proceed and travel during the 8 day construction
  Overview
 

  • Installation of Muni manhole and duct bank
  • Utility installation
  • Installation of high pressure water line

Details

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

What:  Low pressure water line/AWSS
Time:  7a.m. - 4p.m.
When:  Monday to Friday
Where:  4th Street and Welsh Street

  What to expect

  • Work may involve saw-cutting, potholing and jack-hammering on the roadway and sidewalk
  • Sidewalk access may be limited
  • Access will remain open for pedestrians and businesses
  • Muni Service Impact
  • For Muni service impacts for the November 6 through 4th construction
  • Parking and Traffic Impact
    • Parking will be unavailable along the work area
    • Westbound lane on King Street closed during working  hours
    • Northbound lane on 4th Street closed during working hours

Water reflects on a temporary shoring structure after rain inside the YBM headhouse Yerba Buena | Moscone Station

4th Street from Howard to Folsom

Work along 4th Street between Howard Street and Folsom Street 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 and rebar placement.
 

A bobcat is shown removing material underneath temporary steel reinforcements called "walers" Massive amounts of rebar are used when constructing the structural elements of the station.  At the north end of the station box interior, workers are assembling the rebar cages for the slab which will separate the mezzanine from an interior air plenum above Overview
 

  • Excavation
  • Rebar placement

Details

What: Excavation
Time:  7a.m.-7p.m.
When:  Monday to Friday
Where: Howard  Street to Folsom Street

What: Rebar placement
Time:  8:30a.m. to 4:30 p.m.
When:  Saturday
Where: 4th Street
  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
    • Two lanes of traffic open on the east side of 4th Street

Rebar lattice marks where walls will be added to separate a new ramp from the station entrance Union Square | Market Street Station

For the duration of the project, you'll see work along Stockton Street between Ellis Street and Post Street. 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 and compensation

Single-lane traffic continues until the November construction moratorium on Geary at Stockton for pile installation.

The team is preparing for Winter Walk 2015.  For more information, click here. 

Rebar specialists and carpenters are hard at work constructing new vehicle ramps inside the southeast corner of the Union Square Garage Another section of completed roof deck lies just north of  O'Farrell on Stockton. Soon, workers will install sheets of waterproofing material and test them before backfilling the site Overview

  • Installation of roof deck
  • Utility relocation and support
  • Excavation at north concourse
  • Partial demolition and remodeling of Union Square Garage
  • Rebar installation

Details

What: Roof deck, utility, excavation, rebar installation and partial demolition of Union Square Garage
Time: 7a.m.-11p.m.
When: Monday to Saturday
Where: Ellis Street to Post Street
* 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 late November. 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 mid-November. 
  • When Ellis reopens, vehicles will not be able to turn onto Market Street as part of the Safer Market Street project.  For more information, please visit https://www.sfmta.com/projects-planning/projects/safer-market-street
  • Stockton Street between Ellis Street and Post Street is closed to vehicular traffic 

A worker uses a steel cable to right the bucket after soil is dumped in the collection pile Chinatown Station The construction of an underground Chinatown Station uses the sequential excavation method (SEM) along Washington Street and Stockton Street. 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, trenching and connection of dewatering wells, and north access (emergency exit) shaft construction. 
  Levels of excavation inside the station are carefully prepared so excavation can clear the temporary steel supports spanning the width of the headhouse The steel bucket used to remove soil from the station headhouse interior is lifted toward the sky, as seen from the bottom Overview

  • Excavation of station site
  • Connection of dewatering wells
  • Installation of temp bracing
  • North access (emergency exit) shaft construction

Details

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

What:  Connection of dewatering wells
Time:  7a.m -5p.m.
When: Monday to Friday
Where: Stockton Street, Sacramento Street to Jackson Street

What:  Installation of temp bracing
Time:  7a.m -5p.m.
When: Monday to Friday
Where: Stockton Street

What:  North access (emergency exit) shaft construction
Time:  7a.m -5p.m.
When: Monday to Friday
Where: Stockton Street, Washington to Jackson Street

  What to expect

  • Sidewalk access may be limited at times
  • Parking and Traffic Impact
    • Detours will be in place between the hours of 9p.m.and 5a.m. during dewatering wells installation
    • Parking will be unavailable during PG&E work
    • No parking on both sides of Stockton between Washington and Jackson
    • 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.