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NATM

North Shore Connector

Service Performed
Alternative NATM tunnel design, cost estimate & finite element analysis.
Commencement - Services
July 01, 2002
Completion - Services
January 01, 2008
Location
Alpha Dr, Harmar Township
Pittsburgh, PA 15238
United States
Technical data

NATM running tunnel connecting Convention Center station with surface to be constructed beneath historic downtown structures as part of existing LRT system expansion. Provided initial design package, including detailed cost estimate. Tunnel Length: ~446'* Cross Section: 41'-4" x 26'-11"; 895.24 ft^3 *Including widening zone for track cross-over.

Geology description

Fill, alluvium (granular and cohesive), fluvioglacial deposits and bedrock.

Geology types
Description

The North Shore Connector Project consisted of three underground station structures and running tunnels, excavated with TBM and Cut-and-Cover tunneling methods. It also included a twin bore tunnel under the Allegheny River. Dr. Sauer and Partners provided design review and design support services. The development of the waterproofing system for underground structures including tying into an existing station using a flexible membrane system, combined with a sectioning system that allows for section grouting instead of the entire structure if a leak is detected was also provided.

Activity
Final cost
$7,600,000
Construction methods
Project overview
Cut-and-Cover method
Project number
361D
Final cost
$7.6 million USD

3rd Street Light Rail Project - Chinatown Station

Service Performed
Tunneling Sub-Consultant on NATM Subway station design
Estimated cost
$763,800,000
Commencement - Services
January 01, 2002
Completion - Services
October 22, 2003
Location
San Francisco, CA
United States
Technical data

Conceptual and preliminary engineering services for the Chinatown Station of the MUNI Light Rail System in San Francisco. The responsibilities include constructability evaluations, alignment and construction alternatives studies and preparation of preliminary design documents. Alternatives, including deep bored tunnel vs. shallow NATM tunneling will be evaluated.

Geology description

Rugged bedrock hills consisting of highly deformed fractured rock of the Franciscan formation, overlain by sedimentary marine deposits (Colma Sands), fluvial deposits (Alluvium) and artificial fill. Very dense sands, inter-fingering of moderately plastic stiff silty clay.

Construction methods
NATM

DART - Dallas Area Rapid Transit, Tunnels Inspection

Service Performed
Design and Supervision of Leak Remediation Measures
Location
Dallas, TX
United States
Technical data

Leak remediation measures at the East and West Connector to the Mezzanine Level of City Place Station. Measures consistend of joint and crack grouting, the installation of a felxible membrane lining on the structural concrete lining and a cleaning of the existing drainage system.

Description

Leak remediation measures at the East and West Connector to the Mezzanine Level of City Place Station. Measures consistend of joint and crack grouting, the installation of a felxible membrane lining on the structural concrete lining and a cleaning of the existing drainage system.

Construction methods
NATM

Graebnertunnel Westroehre

Service Performed
NATM Excavation and Support Design
Commencement - Services
July 01, 2001
Completion - Services
October 01, 2003
Location
Carinthia
Austria
Technical data

Two Lane Highway Tunnel Length: 7,047 ft (2,1km); Height: ~35 ft x ~29 ft; Section: ~840 ft2 (78.4m2) Excavation included 4 vehicular cross passages connecting existing east tunnel. Constructed using two headings from North (drill-blast) and South (mined-excavator); Grouted pipe arch for pre-support and rock anchors where needed.

Geology description

Difficult tunneling conditions as result of the presence of the Lavantal fault, un-favorable bedding and severe jointing of gneiss and mica schists.

Final cost
$38,000,000
Construction methods
NATM

Washington Dulles Airport Pedestrian Walkback Tunnel

Service Performed
Final design including FEM structural calculations.
Commencement - Services
February 01, 1998
Completion - Services
December 01, 2001
Location
45045 Aviation Drive
Dulles, VA 20166-7528
United States
Technical data

Pedestrian Walkback tunnel, accommodating two moving and one central fixed walkways, 770 ft long, Section of 41 ft x 27 ft. A Mechanical Room with a 37 ft long x 32 ft. span . Tunnel passing 15 ft beneath the main airport taxiways.

Geology description

Residual soils, decomposed rock and siltstone bedrock.

Geology types
Description

An extensive underground people-mover train system and a fixed walkway tunnel between terminals are central to a multi-phased mega program of modernization and expansion for the Washington Dulles International Airport. The pedestrian walkback tunnel, a part of the expansion plan, crosses below two airport taxilanes and will connect the Main Terminal with Mid-Field Concourse B. The tunnel was designed as a multiple-drift NATM excavation, whereby cover beneath the taxilanes was less than a tunnel diameter at only 4.5 m. Excavation was therefore designed as a very controlled sequence with top heading excavation further divided into two side drifts.

Activity
Categories
Final cost
$13,000,000
Construction methods
NATM
Max Overburden
Min:10 Max:20
Max Excavation Area (m2)
Min:1200 Max:1200
Tunnel length
Min:770 Max:770
Walkback tunnel cross section
Access shaft and portal under taxilane
The new tunnel in relation to the airport taxiways
Excavation of Access Shaft
View from Portal to Main Terminal Building
Excavation of Connector Shaft at Junction to Walkback Tunnel
Roadheader entering the Tunnel
Access Tunnel Walkback Tunnel Junction
Access Tunnel Walkback Tunnel Junction
Walkback Tunnel Shotcrete Canopy
Flexible Membrane Waterproofing System applied to Tunnel Invert
Installation of Waterproofing System in Connector Shaft
Fixing of Waterproofing Membrane
Completed Shotcrete Final Lining
Shotcrete canopy, girder erection
Shotcrete Arch - South
Shotcrete Arch - South
Hanging Steel Mesh
Hanging Steel Mesh
Hanging Steel Mesh
Girder completly installed
Shotcrete canopy completed
Project number
207D
Final cost
$13 million USD

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