Bertha STP Repair Plan May2014-1

8/18/2019 Bertha STP Repair Plan May2014-1

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June 2014Seattle Tunnel Partners, WSDOT’s

contractor for the SR 99 TunnelProject, is building a pit to access

and repair Bertha, the SR 99

tunneling machine. The following

images illustrate STP’s

conceptual plan for resuming

tunneling.

Repairing the

SR

TUNNELING

MACHINE


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November:

STP provides

WSDOT with

a full list of

repairs

April May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March

2014 2015

April 21: STP announces new schedule

Late May: Underground wall

construction begins

Late July: Access pit

excavation begins

October: STP begins

repairs to seal system

and replacement of

main bearing February:

Testing ofmachine

begins

March 2015:

Tunneling

resumes

June 16:

STP/Hitachi

announce

repair plan

Seattle Tunnel Partners’ repair schedule

Seattle Tunnel Partners’ repair plan – June 2014 2


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Looking southeast

toward the site wherecrews are bui lding a120-foot-deep circular

pit to access and repairBertha. Contractor

Seattle Tunnel Partners

built the white walls onthe west side of the SR

99 Alaskan Way Viaductto minimize noise during

construction.

Access pit site today, above ground

CONCEPTUAL

3Seattle Tunnel Partners’ repair plan – June 2014


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This underground view

shows Bertha’s currentlocation between SouthJackson and South Main

streets in Seattle. The redline shows the path

Bertha will take once she

resumes tunneling. Thesections of gray on both

sides of Bertha areunderground walls built to

protect the Alaskan WayViaduct and nearbybuildings from settlement

during the initial section ofthe tunnel drive.

Access pit site today, below ground

CONCEPTUAL



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CONCEPTUAL

The dark gray areas in

this image show wheregrout was injectedbetween segments of

existing undergroundwalls on the east and

west sides of Bertha.

The grout furtherstabilizes the ground

and is one of many toolsSTP will use to keep

water out of the access pit. The grout injectionwas completed on

schedule in May 2014.

Step 1: Inject grout between existing piles

CONCEPTUAL



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CONCEPTUAL

Step 2: Relocate utilities (after)This image shows where

sewer, electrical,telecommunications andwater lines are being

relocated to make roomfor construction of the

access pit. Utility

relocation started onschedule in May 2014.



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CONCEPTUAL

Step 3: Inject grout behind the machineSTP crews injected a

wall of grout near theback of the machine’sshield to seal water out

of the access pit. Thiswork was completed on

schedule in May 2014.



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CONCEPTUAL

Step 4: Build the access pit’s walls STP crews are installing

concrete columns thatwill form theunderground walls of the

circular access pit. Madeup of 73 columns, the pit

will be about 120 feet

deep and more than 80feet wide. Underground

wall construction startedon schedule in May

2014.



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Step 4: Build the access pit’s walls STP crews are installing

concrete columns thatwill form theunderground walls of the

circular access pit. Madeup of 73 columns, the pit

will be about 120 feet

deep and more than 80feet wide. Underground

wall construction startedon schedule in May

2014.

CONCEPTUAL



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Step 5: Lower groundwater, tunnel into wallSTP crews will install

wells to lowergroundwater near theaccess pit. This will

make i t easier for themachine to tunnel

through the soil and into

the pit wall.

CONCEPTUAL



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Step 6: Excavate, then tunnel into access pit After the access pit has

been excavated, Berthawill tunnel into the pit. Aconcrete cradle will hold

Bertha in place whileshe is being repaired.

CONCEPTUAL



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Step 7: Install a crane above the access pit A large crane wil l be

installed above theaccess pit to l ift piecesto the surface for repair.

The crane will be similarto the one used to

assemble Bertha in her

launch pit beforetunnel ing started in July

2013.

CONCEPTUAL



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Step 8: Remove pieces, make repairsCrews will repair Bertha

at the surface beforereassembling her in theaccess pit. STP will

thoroughly test Berthabefore tunneling

beneath downtown.

CONCEPTUAL



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STP plans to resume tunneling in March 2015

CONCEPTUAL

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Bertha STP Repair Plan May2014-1

Documents

Transcript of Bertha STP Repair Plan May2014-1