Construction Updates

Tunnel pre-construction work is now underway on Ellis Street. The tall machine shown here on the right is used to perform ground stabilization work known as jet grouting.

Tunnel pre-construction has continued to ramp up in recent weeks as tunneling contractor Barnard Impregilo Healy mobilized at two new sites along the project alignment:

• Around Union Square, work is underway on Stockton Street to prepare to construct below-ground walls, called headwalls, which will become permanent components of the future Union Square/Market Street Station. On Ellis Street, the contractor is performing ground stabilization work known as jet grouting. To facilitate construction, traffic modifications have gone into effect on Stockton Street, Ellis Street and Grant Avenue.

• In North Beach, the contractor began relocating utility lines along Columbus Avenue between Union and Powell streets. This work will be underway for approximately four months, with additional construction on track to begin next year.

Also in Union Square, contractor Synergy Project Management has finished most major utility relocation work at the future site of the Union Square/Market Street Station. Sidewalks and streets in the area have been restored, and only cleanup, detail work and below-ground AT&T and PG&E work remain before this contract is completed.

The sidewalks and stores on Stockton Street are open to pedestrians and shoppers during Central Subway construction.

Here’s what to expect in the next three weeks as tunnel pre-construction continues in SoMa, Union Square and North Beach:

• Tunnel Launch Box (4th Street between Bryant and Harrison streets): The contractor will continue constructing below-ground walls around the perimeter of this major excavation site. Current work hours here are 5 a.m. to 1 a.m., Monday through Friday, and 6 a.m. to 2:30 p.m. on Saturday. At least two lanes of traffic on 4th Street will remain open at all times.

• Yerba Buena/Moscone Station Headwalls (4th Street between Folsom and Howard streets):  The tunneling contractor will install below-ground walls, called headwalls, at the site of the future Yerba Buena/Moscone Station. The walls will cross 4th Street at two points on this block. Current work hours at this site are 7 a.m. to 4 p.m., Monday through Friday. At least two lanes of traffic on 4th Street will remain open at all times.

• Union Square Tunneling Pre-Construction (Stockton Street between Ellis and Geary streets and Ellis Street between Stockton and Powell streets): The contractor is performing utility demolition, potholing and ground stabilization work called jet grouting. Installation of below-ground walls, called headwalls, will follow. Current construction hours at this site are Monday to Friday, 7 a.m. to 5 p.m. For more information about the traffic modifications now in effect in the Union Square area, check out this recent blog post.

• North Beach Utility Relocation (Columbus Avenue between Union and Powell streets): The contractor will continue with utility relocation. Construction hours are Monday through Friday, 7 a.m. to 3:30 p.m. One lane of traffic will be closed at a time on one block of Union Street, Powell Street or Columbus Avenue during construction hours. For more information on construction in North Beach, check out this recent blog post.

A complete, current three-week construction schedule, including detailed, site-specific transit and traffic impacts, is available online for the tunnel contract. We also post construction, auto detour and Muni impact information on our project Google Map.

We appreciate your continued patience while construction is in progress.

Central Subway construction will take place on this block of Columbus Avenue near Washington Square Park.

Construction associated with the Central Subway tunnel will begin August 13 in North Beach. The work involves relocating utility lines on a half-block section of Columbus Avenue between Union and Powell streets.

The Central Subway tunnel is planned to extend past the last station in Chinatown to North Beach. When tunneling is complete, the tunnel boring machines (TBMs) will be removed from the ground on Columbus Avenue. The utility work is expected to take approximately four months to complete and is required to prepare for construction of the TBM retrieval shaft.

Surface construction activity will be take place on Columbus Avenue between Union and Powell streets, with some work at the intersection of Columbus Avenue and Union Street. Construction hours will be Monday through Friday, 7 a.m. to 3:30 p.m. To mitigate construction impacts, street sweeping will occur on a daily basis, dust and noise will be monitored and controlled, and a traffic control officer and a flagger will facilitate the flow of traffic during work hours.

This map shows the approximate location of construction in North Beach. 

 North Beach Construction Plan: Key Details

• Starting August 13, the contractor will perform potholing within the construction zone. Relocation of a fire hydrant water line, Muni overhead contact system (OCS) line, low-pressure water line and AT&T duct bank will follow.

• Construction of a TBM retrieval shaft is planned to begin in early 2013 and continue for approximately 10 months. The retrieval shaft will be constructed on Columbus Avenue between Union and Powell streets. During this time, traffic on this section of Columbus Avenue will be reduced to one northbound lane and one southbound lane.

• After the retrieval shaft is constructed, it will be covered with decking and all lanes of traffic will be restored.

• The TBMs will be retrieved in 2014 after tunneling is complete. When the TBMs are removed, traffic will be temporarily impacted.

• No Central Subway construction is planned to occur in North Beach after the TBMs are removed in 2014.

Details about the upcoming utility relocation are as follows:

• Location: Columbus Avenue between Union and Powell streets, and Union Street between Powell Street and Columbus Avenue.

• Construction hours: Monday through Friday, 7 a.m. to 3:30 p.m.

• Transit impacts: The bus stops on Columbus Avenue at Union Street will be temporarily closed one at a time.

• Traffic: No more than one lane of traffic will be closed at a time, and all lanes will be opened at the end of each work day.

• Street sweeping will occur daily on work days.

• Parking restrictions will be in effect.

• A traffic control officer and flagger will facilitate the flow of traffic during construction hours.

• Dust will be monitored and controlled, noise will be kept within required decibel levels, and noise attenuation devices will be used on construction equipment.

More information about is available in the following documents:

• 10-Day Construction Notice
• North Beach Utility Relocation Fact Sheet
• Press Release: Central Subway Project to Start Utility Relocation in North Beach August 13

We appreciate your continued patience while construction is in progress.

Construction of a major excavation known as a launch box is underway on 4th Street between Bryant and Harrison streets. At nearly 500 feet long, 50 feet wide and up to 40 feet deep, the launch box will take up most of the block.

In the next three weeks, work to prepare for tunneling will continue to ramp up, with tunneling contractor Barnard Impregilo Healy Joint Venture beginning to construct below-ground walls, called headwalls, and perform ground-stabilization work, called jet grouting, around Union Square. In addition, utility relocation on a half-block section of Columbus Avenue may begin in North Beach.

To facilitate construction in the Union Square area, new traffic modifications are going into effect on Stockton Street, Ellis Street and Grant Avenue.

Here’s what to expect as tunnel preparation continues and Union Square utility relocation proceeds:

• Tunnel Launch Box (4th Street between Bryant and Harrison streets): The contractor will continue constructing below-ground walls around the perimeter of this major excavation site. Current work hours here are 7 a.m. to 4 a.m., Monday through Friday, and 6 a.m. to 2 p.m. on Saturday. At least two lanes of traffic on 4th Street will remain open at all times.

• Yerba Buena/Moscone Station Headwalls (4th Street between Folsom and Howard streets):  The tunneling contractor is installing below-ground walls, called headwalls, at the site of the future Yerba Buena/Moscone Station. The walls will cross 4th Street at two points on this block. Current work hours at this site are 7 a.m. to 4 p.m., Monday through Friday. At least two lanes of traffic will remain open at all times.

• Union Square Utility Relocation (on and around Stockton Street between Market and Post streets): Utility relocation at the site of the future Union Square/Market Street Station is nearing completion. Work is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.

• Union Square Tunneling Preparation (Stockton Street between Ellis and Geary streets and Ellis Street between Stockton and Powell streets): Work begins July 30 on Stockton Street and in early August on Ellis Street. The contractor will begin by performing utility demolition and potholing. Ground stabilization work, called jet grouting, and installation of below-ground walls, called headwalls, will follow. For more information about the traffic modifications going into effect in the Union Square area, check out this recent blog post.

Complete, current three-week construction schedules are available online for Union Square utility relocation work and for the tunnel contract. We also post construction, auto detour and Muni impact information on our project Google Map.

Current Muni service impacts are described below. As construction begins at additional locations, additional Muni routes may be impacted.

• The 30 Stockton and 45 Union/Stockton began re-routing in January around major construction sites in Union Square and SoMa. These re-routes will continue throughout the duration of Central Subway construction.
• The 8X/8AX/8BX Bayshore Express and 91 Owl Muni bus lines began re-routing this month. These re-routes will continue throughout the duration of Central Subway construction.
• The 38/38L Geary may experience delays around Union Square.

SoMa:

• At both active construction sites, at least two lanes on 4th Street will be open to traffic at all times.
• All I-80 on- and off-ramps will remain open during the day, but brief nighttime ramp closures may be required.
• Traffic delays are anticipated. Motorists are encouraged to use the onramp at Harrison and 7th streets as an alternative to access westbound I-80 while launch box construction is in progress. Those traveling to the peninsula may prefer to access the I-280 via 6th Street or Highway 101 via 10th Street.
• Access to Clementina Street between 4th and 5th streets may be restricted at times, but the contractor will facilitate access for deliveries.
• Sidewalks may be impacted.
• Electronic messaging boards will be in place and parking control officers and flaggers will monitor and facilitate the flow of traffic as appropriate.

Union Square:

• Starting July 30, Stockton Street between Ellis and Geary streets will be closed to all traffic except emergency vehicles.
• Starting July 28, Grant Avenue between Geary and Sutter streets will be converted into a two-way street.
• Ellis Street between Stockton Street and the Ellis Garage will be closed to westbound traffic. One lane will remain open to eastbound traffic. Vehicles exiting the garage will be able to turn left or right onto Ellis Street.
• Stockton Street will remain open to cross traffic at O’Farrell and Geary streets, but temporary lane closures near the intersections may be required.
• Variable message signs and detour signs will be in place, and traffic control officers and flaggers will be on site to direct traffic as appropriate.
• Sidewalks on Stockton Street between Ellis and Geary streets will remain open, but they may be narrowed to facilitate construction.
• Temporary closures of the crosswalk that crosses Stockton Street on the south side of Geary Street may be required.

The suggested detour route around construction in SoMa and Union Square is shown on the map below. The map also shows a traffic reroute for local access to Union Square.

We appreciate your continued patience while construction is in progress.

New Central Subway construction is beginning soon around Union Square.

Beginning Monday, July 30, Stockton Street between Ellis and Geary streets will be closed to all vehicles except emergency vehicles to accommodate construction of the Central Subway tunnel and Union Square/Market Street Station. To facilitate local access to Union Square, Grant Avenue between Geary and Sutter streets will be converted into a two-way street starting Saturday, July 28.

The partial closure of Stockton Street will remain in effect throughout the duration of Central Subway construction except during the annual holiday construction moratorium. From Thanksgiving to New Year’s Day, no Central Subway construction will occur around Union Square, and Stockton Street will be reopened to traffic. Grant Avenue between Geary and Sutter streets will remain a two-way street during the holiday moratorium.

Variable message signs and detour signs will be in place to direct traffic to the detour routes shown on the map below.

This map shows two suggested traffic reroutes: local access to Union Square via Grant Avenue and a detour around Stockton Street for travel to SoMa and I-80.

In addition to the traffic modifications on Stockton Street and Grant Avenue, Ellis Street between Stockton Street and the Ellis Garage will be closed to westbound traffic. One lane will remain open to eastbound traffic. Vehicles exiting the garage will be able to turn left or right onto Ellis Street.

Tunnel preparatory construction, including ground-stabilization work, called jet grouting, and installation of below-ground walls, called headwalls, will begin on and around Stockton Street after the traffic modifications go into effect. Construction of the Union Square/Market Street Station is slated to begin early next year.

More information is available in the following documents:

• Map: Traffic Modifications Around Union Square
• Press Release: Traffic on Stockton Street and Grant Avenue to Be Modified to Accommodate Central Subway Construction around Union Square
• 10-Day Construction Notice for Central Subway Tunnel Contract Work in Union Square

Temporary Pavement Restoration on Geary and Stockton streets

At the site where tunneling will begin next year, contractor Barnard Impregilo Healy Joint Venture is making progress in constructing below-ground walls around the perimeter of the tunnel launch box – a major excavation almost as big as a city block. At other points along the Central Subway alignment, Union Square utility relocation is progressing toward completion, and construction of below-ground walls at the future site of the Yerba Buena/Moscone Station is underway.

In the next three weeks, utility relocation on a half-block section of Columbus Avenue will begin in North Beach, and Muni’s re-routes of the 8X/8AX/8BX Bayshore Express and 91 Owl around Central Subway construction will take effect.

Here’s what to expect as tunnel preparation continues and Union Square utility relocation proceeds:

• Tunnel Launch Box (4th Street between Bryant and Harrison streets): The contractor will continue constructing below-ground walls around the perimeter of this major excavation site. Work hours at this site are 7 a.m. to 9 p.m., Monday through Friday. At least two lanes of traffic will remain open at all times.

• Yerba Buena/Moscone Station Headwalls (4th Street between Folsom and Howard streets):  The tunneling contractor is installing below-ground walls, called headwalls, at the site of the future Yerba Buena/Moscone Station. The walls will cross 4th Street at two points on this block. To prepare to install the headwalls, utility relocation and guide wall construction will be underway. Work hours at this site are 7 a.m. to 9 p.m., Monday through Friday. At least two lanes of traffic will remain open at all times. For more information on traffic, pedestrian and Muni impacts at this site, check out this recent blog post.

• Union Square Utility Relocation (on and around Stockton Street between Market and Post streets): With sidewalks being restored along Stockton Street and road restoration underway, utility relocation at the site of the future Union Square/Market Street Station is nearing completion. Work is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.

Complete, current three-week construction schedules are available online for Union Square utility relocation work and for the tunnel contract. We also post construction, auto detour and Muni impact information on our project Google Map.

Current Muni service impacts are described below. As construction begins at additional locations, additional Muni routes may be impacted.

• The 30 Stockton and 45 Union/Stockton began re-routing in January around major construction sites in Union Square and SoMa. These reroutes will continue throughout the duration of Central Subway construction.
• Re-routes of the 8X/8AX/8BX Bayshore Express and 91 Owl Muni bus lines begin July 11. These reroutes will continue throughout the duration of Central Subway construction
• The 38/38L Geary may experience delays.

SoMa:

• At both currently active construction sites, at least two lanes on 4th Street will be open to traffic at all times.
• All I-80 on- and off-ramps will remain open during the day, but brief nighttime ramp closures may be required.
• Traffic delays are anticipated. Motorists are encouraged to use the onramp at Harrison and 7th streets as an alternative to access westbound I-80 while launch box construction is in progress. Those traveling to the peninsula may prefer to access the I-280 via 6th Street or Highway 101 via 10th Street.
• Access to Clementina Street between 4th and 5th streets may be restricted at times, but the contractor will facilitate access for deliveries.
• Sidewalks may be impacted.
• Electronic messaging boards will be in place and parking control officers and flaggers will monitor and facilitate the flow of traffic as appropriate.

Union Square:

• Currently, traffic on Stockton Street between Market and Post streets is limited to Muni buses, taxis, tour buses, emergency vehicles and delivery trucks only.
• Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.

This video shows the work currently underway on 4th Street between Bryant and Harrison streets in SoMa. The full HD video can be downloaded here.

It may look like a lot of dirt and mud right now, but in just a few years, what you see in the video above will become the Central Subway – a major upgrade to San Francisco’s public transportation system that will significantly improve mobility for thousands of San Franciscans.

The exciting first chapter of constructing the Central Subway tunnel is progressing in SoMa, with construction of a major excavation known as a launch box underway on 4th Street between Bryant and Harrison streets. At nearly 500 feet long, 50 feet wide and up to 40 feet deep, the launch box will take up most of the block.

Currently, tunneling contractor Barnard Impregilo Healy Joint Venture is using cranes and specialized excavators, including a 10-foot-tall, 15-ton, claw-like hydraulic excavator known as a “grab,” to dig a series of deep, narrow holes around the perimeter of the launch box. The holes, ranging in depth from 60 to 80 feet, are stabilized using a mud-like slurry and then backfilled with concrete to form panels. The panels will make up the walls of the tunnel launch box.

The 10-foot-tall, 15-ton “grab” shown here is digging a series of deep, narrow holes around the perimeter of the launch box. The holes are stabilized using a mud-like slurry and then backfilled with concrete to form panels, forming the walls of the tunnel launch box.

Next year two tunnel boring machines will start digging the Central Subway tunnels from the launch box, traveling north under 4th Street and then Stockton Street. The launch box will eventually become the portal where T Third Line trains will enter and exit the Central Subway tunnel, quickly transporting transit customers through SoMa, Union Square and Chinatown.

Here are a few more photos of the work currently underway to construct the Central Subway tunnel:

After using the grab to remove earth from the ground, the crane operator deposits it nearby. Later, the excavated materials will be transported off-site.

This large crane is used to excavate areas that are not beneath the I-80 overpass. A smaller crane (shown in the top photo) is used beneath the I-80 overpass.

These I-beams will be used to stabilize the walls around the launch box.

Motorists traveling south on 4th Street will be directed to access westbound I-80 as shown above while the onramp at 4th and Harrison streets is closed. (Click on the map to enlarge.)

Starting next Monday, June 25, the onramp to westbound I-80 at 4th and Harrison streets will be closed between the hours of 8 p.m. and 4 a.m. This nighttime closure may continue for up to a week to allow for tunnel-related construction.

While the closure is in effect, motorists are encouraged to use the onramp at Harrison and 7th streets as an alternative to access westbound I-80. Variable message signs will be in place on 4th Street and on Harrison Street to direct traffic.

For more information about Central Subway traffic impacts, check out our most recent three-week construction overview.

Construction at the site of the tunnel launch box, shown here, ramped up this week. 

Construction to prepare for the Central Subway tunnel ramped up this week, and the new sidewalks on the west side of Stockton Street are almost completely restored. Here’s what to expect in the next three weeks as tunnel preparation continues and the Union Square utility relocation nears completion:

• Tunnel Launch Box (4th Street between Bryant and Harrison streets): Next week, heavy construction equipment is planned to arrive at the site of the tunnel launch box, and the contractor expects to begin constructing below-ground walls around the perimeter of this major excavation site. At nearly 500 feet long, 50 feet wide and up to 40 feet deep, the launch box will take up most of the block. Next year two tunnel boring machines will start digging the Central Subway tunnels from the launch box, traveling north under 4th Street and then Stockton Street. Work hours at this site are 7 a.m. to 9 p.m., Monday through Friday. At least two lanes of traffic will remain open at all times.

• Yerba Buena/Moscone Station Headwalls (4th Street between Folsom and Howard streets):  The tunneling contractor is installing below-ground walls, called headwalls, at the site of the future Yerba Buena/Moscone Station. The walls will cross 4th Street at two points on this block. To prepare to install the headwalls, utility relocation and guide wall construction will be underway. Work hours at this site are 7 a.m. to 9 p.m., Monday through Friday. At least two lanes of traffic will remain open at all times. For more information on traffic, pedestrian and Muni impacts at this site, check out this recent blog post.

• Union Square Utility Relocation (on and around Stockton Street between Market and Post streets): With sidewalks being restored along Stockton Street and road restoration underway, utility relocation at the site of the future Union Square/Market Street Station is nearing completion. Work is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.

Complete, current three-week construction schedules are available online for Union Square utility relocation work and for the tunnel contract. We also post construction, auto detour and Muni impact information on our project Google Map.

Current Muni service impacts are described below. As construction begins at additional locations, additional Muni routes may be impacted.

• The 30 Stockton and 45 Union/Stockton began re-routing in January around major construction sites in Union Square and SoMa. These reroutes will continue throughout the duration of Central Subway construction.
• The 38/38L Geary and the 8X/8AX/8BX Bayshore Express may experience delays.

SoMa:

• At both currently active construction sites, at least two lanes on 4th Street will be open to traffic at all times.
• All I-80 on- and off-ramps will remain open during the day, but brief nighttime ramp closures may be required.
• Traffic delays are anticipated. Motorists are encouraged to use the onramp at Harrison and 7th streets as an alternative to access westbound I-80 while launch box construction is in progress. Those traveling to the peninsula may prefer to access the I-280 via 6th Street or Highway 101 via 10th Street.
• Access to Clementina Street between 4th and 5th streets may be restricted at times, but the contractor will facilitate access for deliveries.
• Sidewalks may be impacted.
• Electronic messaging boards will be in place and parking control officers and flaggers will monitor and facilitate the flow of traffic as appropriate.

Union Square:

• Currently, traffic on Stockton Street between Market and Post streets is limited to Muni buses, taxis, tour buses, emergency vehicles and delivery trucks only.
• Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.

Construction is now underway on 4th Street near the intersection with Folsom Street.

Construction to prepare for the installation of below-ground walls, called headwalls, has begun on 4th Street between Folsom and Howard streets, the site of the future Yerba Buena/Moscone Station. The work currently underway includes potholing and utility relocation. Headwall installation, which involves major excavation work and will require the use of heavy machinery, will soon follow.

The headwalls will be constructed across 4th Street and reach a depth of about 100 feet. Permanent components of the Central Subway, the headwalls will be integrated into the subway station that will be constructed at this location.

White spray paint outlines the location on 4th Street just north of Folsom Street where headwalls will be installed.

Headwall construction is expected to last through spring 2013. While construction is in progress, those traveling, working and living in the area can expect to see large construction equipment as well as an increase in noise, dust and truck traffic while work is in progress. The Central Subway team will continue to work closely with communities, local businesses and organizations to inform them of construction impacts and to ensure appropriate mitigation measures are in place.

To mitigate construction impacts, dust and noise levels will be monitored and kept within permitted levels, and the contractor will perform street sweeping daily to clean the construction site and surrounding areas.

Access to local businesses, residences and driveways will be maintained.

Transit, Traffic and Pedestrian Impacts

The following describes ongoing and upcoming traffic and transit impacts at the headwall installation site on 4th Street between Folsom and Howard streets:

• The 30 Stockton and 45 Union/Stockton began re-routing in January around major construction sites in Union Square and SoMa. These re-routes will continue throughout the duration of Central Subway construction.

• The 8X/8AX/8BX Bayshore Express and 91 Owl will be rerouted in July, and the temporary 8 Shuttle route will be eliminated. Additional information will be available soon online and in media alerts.

• At least two lanes on 4th Street will remain open to traffic while work is in progress.

• Sidewalks on the west side of the block will be impacted.

• Access to Clementina Street between 4th and 5th streets may be restricted at times, but the contractor will facilitate access for deliveries.

• Parking restrictions will be in effect in and around the construction area.

• Electronic messaging boards will be in place and parking control officers and flaggers will monitor and facilitate the flow of traffic as appropriate.

As work proceeds, additional information on local impacts will be made available here, on Facebook, on Twitter, on our project Google Map and in media alerts. To schedule a briefing on tunnel-related construction for your community group or organization, please contact Brajah Norris at 415-701-5263 or email our team at central.subway@sfmta.com.

More information about the Central Subway tunnel and the tunnel-related work slated for 2012 is available in the following documents:

• Central Subway Blog: Overview of Tunnel Work in 2012
• Central Subway Tunnel Fact Sheet
• Preparing for the Central Subway Tunnel: 2012 Construction Map
• SFMTA Press Release: Construction to Prepare for Central Subway Tunnel Moves Forward, Advancing Vital Extension of Muni Metro T Third Line

We appreciate your continued patience while construction is in progress.

At the site of the tunnel launch box, crews are constructing shallow, below-ground walls to prepare for the major upcoming excavation.

Next year, a pair of tunnel boring machines (TBMs) will begin excavating the Central Subway tunnel, building the backbone of Muni’s extension of the T Third Line through vibrant and bustling SoMa, downtown, Union Square and Chinatown. Next week, major work to prepare for tunneling is ramping up in SoMa, with additional tunnel-preparation work planned to begin this year at new sites along the project alignment.

This new stage of construction will be the first to build permanent elements of the Central Subway, kicking off the next phase of progress on this critical transit upgrade.

The work, to be carried out by tunneling contractor Barnard Impregilo Healy Joint Venture, involves excavating the site where tunneling will begin, stabilizing the ground at key points along the project alignment and relocating utilities at the tunnel’s end point.

This blog post provides an overview of the tunnel-related work slated to take place in 2012. Future posts will contain additional details about what to expect at specific construction sites, including work timelines, construction impacts and descriptions of construction techniques.

A variety of measures, including street sweeping, noise monitoring and traffic controls, will be employed to reduce construction impacts. Access to local businesses, residences and driveways will be maintained throughout construction. However, traffic, transit, parking and pedestrian walkways will be impacted, and travelers through these areas can expect an increase in noise, dust and truck traffic while work is in progress.

This map provides an overview of the construction to prepare for tunneling that will occur in 2012. A PDF of the map can be downloaded here.

The following work is planned to occur this year to prepare for tunneling in 2013:

• Launch Box: Next week, the tunneling contractor will begin excavating and constructing a launch box at the site where tunneling will begin. The launch box will be built on 4th Street between Bryant and Harrison streets, beneath the I-80 overpass. At nearly 500 feet long, 50 feet wide and up to 40 feet deep, this major excavation will take up most of the block. Next year the TBMs will start digging the Central Subway tunnels from the launch box, traveling north under 4th Street and then Stockton Street.

• Headwalls: The contractor will install below-ground walls, called headwalls, at subway station sites in SoMa and Union Square. Headwall installation will take place on 4th Street between Folsom and Howard streets and on Stockton Street between Market and Post streets.

• Grouting: Ground stabilization work, known as jet grouting or compensation grouting, will occur along the project alignment in SoMa and Union Square. This work involves drilling shafts into the ground, monitoring ground conditions and, if necessary, injecting a mud-like substance that acts as a stabilizer.

• Utility Relocation: The Central Subway tunnel will extend past the end of the line in Chinatown to North Beach, paving the way for a potential future extension of the line. Utility relocation in North Beach this year will prepare for excavation of the site where the TBMs will be removed from the ground. Ongoing communications and outreach are underway to determine a schedule for this work.

The Central Subway team will continue to work closely with communities, local businesses and organizations to inform them of construction impacts and to ensure appropriate mitigation measures are in place. As work commences at new locations along the alignment, additional information on local impacts will be made available here, on Facebook, on Twitter, on our project Google Map and in media alerts. To schedule a briefing on tunnel-related construction for your community group or organization, please contact Brajah Norris at 415-701-5263 or email our team at central.subway@sfmta.com.

More information about the Central Subway tunnel and the tunnel-related work slated for 2012 is available in the following documents:

• SFMTA Press Release: Construction to Prepare for Central Subway Tunnel Moves Forward, Advancing Vital Extension of Muni Metro T Third Line
• Central Subway Tunnel Fact Sheet
• Preparing for the Central Subway Tunnel: 2012 Construction Map

We appreciate your continued patience while construction is in progress.

Since breaking ground in January 2011, contractor Synergy Project Management has finished relocating a variety of utility lines around Union Square to prepare for construction of the Union Square/Market Street Station.

Now, with much of this work complete, sidewalks are being restored and reopened for pedestrians.

Check out these pictures of the beautiful new sidewalks (and sidewalks-in-progress) on and around Stockton Street:

Sidewalk restoration in progress at the corner of Stockton and O’Farrell streets.

Wooden railings help stabilize these freshly poured sidewalks as the concrete dries.

Some sidewalks in the area have been completed and are now open to pedestrians.

Stockton Street shoppers, visitors, workers and walkers traverse the brand new sidewalks.

These walls, called guide walls, are being constructed at 4th Street beneath the I-80 overpass to prepare to excavate the site where the Central Subway tunnel will begin.

In the next three weeks, road and sidewalk restoration are planned to begin along Stockton Street, and work associated with the tunnel contract is anticipated to commence on 4th Street between Folsom and Howard streets.

• Union Square/Market Street Station Utility Relocation: Crews are continuing to relocate utilities along Stockton Street between Market and Geary streets to prepare for construction of the Union Square/Market Street Station. Most major utility relocation work, including significant road and sidewalk restoration, is expected to be completed next month. Construction is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.
• Tunnel Launch Site Construction: Work is continuing on 4th Street between Bryant and Harrison streets to prepare the site for tunnel construction. Crews are working to relocate utility lines and install guide walls at the site where tunneling will commence. The contractor expects to begin installing below-ground walls, called slurry walls, around the perimeter of the launch box in June. Work hours at this site are 7 a.m. to 9 p.m., Monday through Friday.
• Yerba Buena/Moscone Station Tunneling Preparation: Work to prepare for tunneling at the site of the Yerba Buena/Moscone Station is planned to commence in June on 4th Street between Folsom and Howard streets. The contractor expects to begin relocating utility lines at this site starting in June. Ground stabilization work, called jet grouting, and installation of below-ground walls, or headwalls, will follow. This work will take place Monday through Friday between 7 a.m. and 5 p.m. The 10-day construction notice for this work is available here.

Complete, current three-week construction schedules are available online for Union Square utility relocation work and for the tunnel contract. We also post construction, auto detour and Muni impact information on our project Google Map.

Muni Service Impacts:

While work is in progress around Union Square and in SoMa, the following Muni routes may experience delays:

• 8 Shuttle/8X/8AX/8BX Bayshore Express
• 38/38L Geary

The 30 Stockton and 45 Union/Stockton lines have been rerouted around the Stockton Street and 4th Street construction sites, effective January 21.

Traffic Detours:

While Union Square utility relocation work is in progress, only Muni buses, taxis, tour buses and delivery trucks will be permitted on Stockton Street between Post and Market streets.

Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.

Crews prepare to pour sidewalk on Stockton Street.

Since our last three-week construction update, work to prepare the tunnel launch site for tunneling and to relocate utilities around Union Square has continued to progress.

In the next three weeks, the following work will be underway:

• Union Square/Market Street Station Utility Relocation: Crews will continue to relocate utilities to prepare for construction of the Union Square/Market Street Station. We expect utility relocations around Union Square to be completed by June 2012.Construction is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.
• Tunnel Launch Site Construction: Work is continuing on 4th Street between Bryant and Harrison streets to prepare the site for tunnel construction. Crews are working to relocate utility lines and install guide walls at the site where tunneling will commence. Work hours are 7 a.m. to 5:30 p.m., Monday through Friday.

The complete, current three-week construction schedule for Union Square utility relocations is available here (PDF). We also post construction, auto detour and Muni impact information on our project Google Map.

Muni Service Impacts:

While utility relocation work is in progress around Union Square, the following Muni routes may experience delays:

• 8 Shuttle/8X/8AX/8BX Bayshore Express
• 38/38L Geary

The 30 Stockton and 45 Union/Stockton lines have been rerouted around the Stockton Street and 4th Street construction sites, effective January 21.

Traffic Detours:

While Union Square utility relocation work is in progress, only Muni buses, taxis, tour buses and delivery trucks will be permitted on Stockton Street between Post and Market streets.

Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.

SFMTA Director of Transportation Edward D. Reiskin, San Francisco Mayor Edwin M. Lee and SFMTA Board Chairman Tom Nolan speaking at a press conference in March.

Hot off the presses: It’s the spring 2012 edition of the Central Subway newsletter. Download it in English or Chinese to learn about the latest project news and to gain insight into community benefits, construction progress and station design.

This edition of the quarterly project newsletter features:

• A project update from SFMTA Director of Transportation Edward D. Reiskin
• Insight into featured artist Tomie Arai’s artwork for the Chinatown Station
• A Central Subway construction update
• And more…

The Central Subway newsletter is also available via email. To have future newsletters delivered directly to your inbox, subscribe to our mailing list here.

A worker inspects a reinforced steel structure at a work site on Stockton and Market streets.

Since our last three-week construction update, work to prepare the tunnel launch site for tunneling and to relocate utilities around Union Square has continued to progress.

In the next three weeks, the following work will be underway:

• Union Square/Market Street Station Utility Relocation: Crews will continue to relocate utilities to prepare for construction of the Union Square/Market Street Station. We expect all utility relocations around Union Square to be completed by June 2012. Construction is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.
• Tunnel Launch Site Construction: Work is continuing on 4th Street between Bryant and Harrison streets to prepare the site for tunnel construction. Crews are working to relocate utility lines and install guide walls at the site where tunneling will commence. Work hours are 7 a.m. to 5:30 p.m., Monday through Friday.

The complete, current three-week construction schedule for Union Square utility relocations is available here (PDF). We also post construction, auto detour and Muni impact information on our project Google Map.

Muni Service Impacts:

While utility relocation work is in progress around Union Square, the following Muni routes may experience delays:

• 8 Shuttle/8X/8AX/8BX Bayshore Express
• 38/38L Geary

The 30 Stockton and 45 Union/Stockton lines have been rerouted around the Stockton Street and 4th Street construction sites, effective January 21.

Traffic Detours:

While Union Square utility relocation work is in progress, only Muni buses, taxis, tour buses and delivery trucks will be permitted on Stockton Street between Post and Market streets.

Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.

Traffic controls are in place to direct traffic safely around the construction site.

Starting Friday, April 13, crews will begin constructing guide walls on the east side of 4th Street between Harrison and Bryant streets. Guide wall construction will involve excavation of a trench on 4th Street. This will be followed by minor concrete work. The guide walls will prepare the Central Subway alignment for construction of slurry walls and a launch box at the site where the tunnel boring machines will begin tunneling.

Guide wall construction is expected to last for approximately three weeks. Approved work hours are 7 a.m. to 5:30 p.m., Monday through Friday. Access to 4th Street from Perry Street and Stillman Street may be briefly restricted, but advance notification will be provided to impacted residents and businesses should these closures be necessary. No detours are planned, and traffic controls will be in place. There may be an increase in truck traffic while this work is in progress.

Work to demolish and relocate utility lines remains in progress on this block and is expected to continue through May.

More information about construction of the Central Subway tunnel is available in this construction notice. To learn more about Central Subway construction, please visit our website or our project Google Map.

An excavator at the construction site on 4th Street.

Work to demolish and relocate utility lines has commenced along 4th Street between Harrison and Bryant streets. The purpose of this work is to prepare the Central Subway alignment for construction of a launch box at the site where the tunnel boring machines will begin tunneling.

Up to two lanes may be closed on 4th Street between Bryant and Harrison streets while this work is in progress. The I-80 East off-ramp and the I-80 West on-ramp will remain open, although some lanes may be closed. Starting April 2, the intersection of 4th and Harrison streets may be partially obstructed. No detours are planned, and traffic controls will be in place while this work is in progress.

The sidewalk on the west side of the street may be closed for a portion of  this work. During these times, pedestrians should use the sidewalk on the east side of the street.

After this utility work is complete, crews will begin installing slurry walls to prepare for construction of the tunnel launch box.

More information about construction of the Central Subway tunnel is available in this construction notice. To learn more about Central Subway construction, please visit our website or our project Google Map.

Demolishing a basement floor at 17 to 19 Stockton Street.

Since our last construction update, Central Subway contractors have continued to make progress, completing the following work:

• Drilling operations around Union Square to collect information about the chemical conditions of soil and groundwater
• Installation of a decorative wrap at 933 to 949 Stockton Street, the future site of the Chinatown Station
• Installation of a high-pressure water line on Geary Street at Stockton Street
• Demolition of sidewalk and basement floor on the west side of Stockton Street between O’Farrell and Market streets (see above photo)

Here are some photos of our crews at work around Union Square:

Installing a joint trench on O’Farrell Street.

Applying waterproofing material at Ellis and Stockton.

Preparing to pave O’Farrell Street.

In the next three weeks, crews will continue to relocate utility lines around Union Square to prepare the area for construction of the Union Square/Market Street Station. We expect all utility relocations around Union Square to be completed by June 2012. Construction is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.

The complete, current three-week construction schedule for Union Square utility relocations is available here (PDF). We also post construction, auto detour and Muni impact information on our project Google Map.

Muni Service Impacts:

While utility relocation work is in progress around Union Square, the following Muni routes may experience delays:

• 8 Shuttle/8X/8AX/8BX Bayshore Express
• 38/38L Geary

The 30 Stockton and 45 Union/Stockton lines have been rerouted around the Stockton Street construction site, effective Jan. 21.

Traffic Detours:

While the utility relocation work is in progress, only Muni buses, taxis, tour buses and delivery trucks will be permitted on Stockton Street between Post and Market streets.

Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.

Mayor Lee spoke about the benefits of the Central Subway today at a press conference in Chinatown.

The Central Subway will improve public transportation in San Francisco, create thousands of jobs and enhance the quality of life of residents and visitors alike. That’s what Mayor Edwin M. Lee and other local leaders and community members said at a press conference today at the site of the future Chinatown Station, hailing the Central Subway as an essential and much-needed investment in the city’s infrastructure and economic future.

“Once the Central Subway is built, this new light-rail extension will be an engine for job creation and economic growth in our city, connecting our vital neighborhoods and diverse communities,” said Mayor Lee. “This important investment in our city’s infrastructure will improve transportation options, reduce emissions and enhance the quality of life of residents and visitors.”

Mayor Lee, San Francisco Municipal Transportation Agency (SFMTA) Board of Directors Chairman Tom Nolan, San Francisco Board of Supervisors President David Chiu and others gathered to unveil a decorative vinyl wrap installed at the site of the future Chinatown Station. The wrap, which features renderings of the station design, a mural provided by the Chinese Historical Society of America and artwork by students from the Chinatown YMCA, will protect and enhance the appearance of the now-vacant building at 933 to 949 Stockton Street until it is demolished later this year.

The building has been acquired by the SFMTA, and, with SFMTA assistance, all residential and commercial tenants have successfully relocated.

Top: 933-949 Stockton Street with the artistic wrap. Bottom: The building before the wrap was installed.

The station, a subway station to be constructed at the southwest corner of Stockton and Washington streets, will feature an open, contemporary aesthetic that emphasizes transparency and simplicity. Light-colored and reflective surfaces will maximize lighting efficiency and create a bright, welcoming atmosphere even when customers are below ground. Artwork selected through the San Francisco Arts Commission’s Public Art Program will adorn the station and provide insight into local culture and history.

These renderings depict the design of the Central Subway Chinatown Station.

The Central Subway Project has achieved major milestones in recent months, and more progress is on the horizon this year:

• The contract for the Chinatown Station has been advertised. Bids on the estimated $235 million contract are due May 8.
• Contracts for the other three Central Subway stations are on track for advertisement this spring and summer.
• Work to prepare the project alignment for the construction of a 1.6-mile tunnel is on track to commence this spring.
• In his budget proposal for fiscal year 2013, President Obama included a recommendation for $150 million in funding for the Central Subway Project.
• For the fifth consecutive year, the project received a strong positive rating from the Federal Transit Administration in its annual New Starts review. This indicates that a Full Funding Grant Agreement for nearly $1 billion in New Starts funding may be forthcoming.

To find out more about the Chinatown Station and recent progress on the Central Subway Project, check out this press release (PDF) from Mayor Lee’s office.

Utility relocation work around Union Square. Feb. 11 – March 2, 2012.

Crews are continuing to relocate utility lines around Union Square to prepare the project alignment for the Union Square/Market Street Station. We expect all utility relocations around Union Square to be completed by June 2012. The complete, current three-week construction schedule for Union Square utility relocations is available here (PDF). Construction is scheduled seven days a week from 7 a.m. to 7 p.m., although night work may be necessary.

Drilling operations are underway around Union Square to collect information about the chemical conditions of soil and groundwater. This work is expected to be completed by mid-March. Parking spaces may be temporarily closed as needed during construction. More information is available on our construction notice.

At 933-949 Stockton Street, the location of the future Chinatown Station, a decorative vinyl wrap will be applied along Stockton and Washington streets to protect the now-vacant building from vandalism and enhance its appearance until it is demolished. Work to install the vinyl wrap, remove signage and secure the building is expected to continue through mid-March. While work is in progress, a temporary walkway (shown below) will be in place to ensure pedestrian safety. For more information, check out our construction notices, which are available in English and Chinese.

A temporary walkway has been set up on Stockton Street to keep pedestrians safe while the vinyl wrap is being installed.

This building is located at the site of the future Chinatown Station.

Muni Service Impacts:

While utility-relocation work is in progress around Union Square, the following Muni routes may experience delays:

• 8 Shuttle/8X/8AX/8BX Bayshore Express
• 38/38L Geary

The 30 Stockton and 45 Union/Stockton lines have been rerouted around the Stockton Street construction site, effective Jan. 21.

Traffic Detours:

While the utility relocation work is in progress, only Muni buses, taxis, tour buses and delivery trucks will be permitted on Stockton Street between Post and Market streets.

Two traffic detour options are in place to allow for better access to the Union Square area and to aid the flow of traffic:

We appreciate your continued patience while construction is in progress.