Westside Purple Line ExtensionLos Angeles, California. USA

October 13, 2015

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Los Angeles Metro Existing Fixed Guideway System

n Metro Blue LRT 35.4 kmn Metro Green LRT 32.2 kmn Metro Gold Pasadena LRT 22.0 kmn Metro Gold Eastside LRT 9.7 kmn Metro Expo LRT 13.8 kmn Metro Red & Purple HRT 28.0 km

Total 141.1 kmn Metro Orange BRT (Busway)20.9 km

Current LA Metro Underground Rail Projects in Construction

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Measure R Westside Transit Program• ½ cent sales

tax for Los Angeles County passed in 2009

• projected to raise $40 B over 30 years

• 35% to new rail and bus projects

• 20% for new car pool lanes

• 20% for bus operations

• 15% for local city sponsored improvements

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Westside Subway Extension

• 8.9 mile extension of Metro Purple line• 7 new stations • 78,000 New Daily Trips• 25 minutes travel time Downtown –

Westwood

Section1 – Wilshire Western to Wilshire La Cienega• FTA Record of Decision

for all three sections – August 9, 2012

• FTA Full Funding Grant Agreement for Section 1 – May 21, 2014

• Delivery– 3 Advance Utility

Relocation Contracts– A single design-build

contract for the twin –bored tunnels and 3 new underground stations. Contract NTP issued on

• Revenue Service Date: – FFGA – October 31,

2024– Forecast – November

2023

Section 2 – Wilshire La Cienega to Century City

• FTA Full Finding Grant Application is in process

• Delivery– One advance utility

relocation contract– One design build

contract for twin bore tunnels and two underground stations

• RFP / RFQ contract solicitation documents for the design build contract were issued on 14-Sep-15

Section 3 - Century City to Westwood VA Hospital

• Originally scheduled for completion in 2036

• Completion date may be brought forward to 2024 in support of Los Angeles Bid for 2024 Summer Olympics

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BIM Modeling

• Design– 3-D design on one

platform– Coordination and

Integration• Construction

– QA / QC data base• Operation and

Maintenance– Asset

Management

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BIM Modeling – Underground Utilities

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BIM Modeling – Interfaces with Existing Properties

Tunnels

Geology

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Geology

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Tunnel Section

5750 mm ID300 mm Precast Segment150 mm Secondary linerHCR membrane

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Cross Passage

Cross Passages at 800 ft (245

m) max.

38’-10” (11,838

mm)

Tunnelling Challenges

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Seismic

• Omega Seals and/or Steel liners provide flexibility at tunnel /station interface

• Steel liners and/or oversize tunnel through fault zones

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Seismic

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Oil Fields

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Oil Fields

• Active oil field adjacent to alignment at Century City

• Locating abandoned oil wells is a challenge

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Methane Zones

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Tunnelling through Gassy Ground

Closed Face TechniquesIsolation and VentilationA closed face Slurry Machine isolates

tunnel interior and construction crews from contact with the tunnel muck and ground water.

EPB machines do not normally contain muck beyond the end of the screw conveyor , but ……….

EPB muck can be diluted to make a pumpable slurry

Gas neutralizing agents can be mixed with soil in front of the EPB machine to reduce off-gassing of soil and ground water

Tunnel segments that seal out water and gas

Ventilation to deal with gases that do

enter the tunnel

Double Gasket Segments

• Double gasket liners have been used successfully on Metro Gold Line

Tunneling Operations from Below the Street

Stations

Typical Metro Underground Station

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Cut and Cover Construction

Modular Subway Station

Unity between Sections of the Project

1. Identity and public awareness2. Simplifies Design &

Construction3. Systemwide Operation and

Maintenance

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Station Water / Gas Proofing Concept

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Station Construction

Steel soldier piles, wood lagging and struts Slurry walls / secant piles may be used where

groundwater or gas and tar are concerns Concrete deck panels are placed on deck beams

over the excavation during construction. Excavation occurs from beneath the deck.

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Station Cut-and-Cover Construction Planning

The tunnel access shaft and staging area located at the station site ultimately becomes the underground subway station.

Off-Street Construction Staging Area

Station construction under temporary concrete deck panels

Traffic is maintained above the excavation

during station construction

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Soldier Piles and Deck Beams

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Deck Beams and Temporary Street Concrete Panels

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Earth Backfill and Final Street Restoration

StationChallenges

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Utility Relocation

Third party coordination has begun with the City, County, State agencies and utility companies. 3-D CADD modeling is being used to determine utility conflicts.

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Utility Relocation and Temporary Support

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Naturally-occurring Tar Pits

Fossils are boxed and removed from the excavation

Fossils are then separated from the tar sand matrix

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Fossil Removal

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Exploratory Shaft

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Building Protection

THE END

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