Baltimore Metro - Section C

Location: Baltimore, Maryland
Owner: Maryland Mass Transit Administration
Role: PB was retained, in joint venture, to provide final design and construction related services during the Baltimore Metro - Section C project.
PM: Colin Lewis
Date: Scheduled for completion in 1996.

SPTC walls with reinforcing between soldier piles were selected for the permanent walls of the 186-m- (610-foot-) long Shot Tower Station. An approximately 12-meter (40-foot) section of the main station was constructed using a jet-grouted cutoff wall in order to accommodate and not disturb existing electrical lines. (see "Constructing Slurry Walls For Baltimore’s Shot Tower Station")

Panchiao Extension Project

Location: Taipei, Taiwan
Client: Taipei Railway Underground Project Office
Role: PB was involved in all phases of the Panchiao Extension Project, served as general consultant and provided detailed design review and construction advisory services for a segment of the railway undergrounding program.
PM: Norman Crook
Date: Completed in 1996.

Project site is characterized by a high groundwater table and relatively poor soil; some adjacent building foundations are less than 1 meter (3 feet) from the excavation. Braced slurry walls were used for most of the temporary support where deep excavations were required. Slurry walls with eight levels of bracing were required near the Hsintien River, where the excavation depth exceeds 24 meters (78 feet).

63rd Street Tunnel Connection

Location: New York, New York
Client: MTA NYC Transit
Role: PB, in joint venture, is providing final design services including design support during construction and contract close-out.
PM: Lou Silano
Date: Revenue service expected to begin in 2001.

More than 900 m (3,000 feet) of slurry walls are proposed in a portion of the project where new track sections will cross under the existing Queens Boulevard Line tracks prior to merging with them. The walls will control groundwater, providing a relatively watertight enclosure in an area where external dewatering could not be used because of the potential impact of drawdowns on nearby contaminant plumes and consolidation of peat deposits below nearby structures. (see "Using Slurry Walls to Control Groundwater During Subway Construction")

Beth Israel Hospital Clinical Center

Location: Boston, Massachusetts
Owner: Beth Israel Hospital
Role: PB, as a subconsultant to an architectural firm, provided design management and construction services for the underground portions of the clinical center.
PM: Eldon Abbott
Date: Completed in 1996.

Project included the construction of a five-level underground garage that provided foundation support for a 20-story medical facility. Construction included slurry walls to reduce impacts to adjacent buildings. The slurry wall was designed for two future openings— a service tunnel and a connection to a future adjacent garage.

Rio Salado Town Lake Project

Location: Tempe, Arizona
Client: Engineering Division, City of Tempe
Role: PB will provide full construction administration services.
PM: Ollie Park
Date: Scheduled for completion in February 1998.

Plan calls for converting a section of the Salt River channel into a recreational lake. Approximately 1.6-kilometer- (1-mile-) long slurry bentonite cut-off walls will be constructed in the channel invert paralleling the lake boundary. The walls will be up to 15 m (50 feet) deep and will minimize seepage from the downstream half of the lake area.

North-South Toll Road Construction Inspection

Location: Chicago, Illinois
Client: Illinois State Toll Highway Authority
Role: PB provided construction inspection services.
PM: James Gunraj
Date: Completed in 1989.

Project included 600 m (2,000 feet) of slurry wall construction.

Harvard Square Station

Location: Cambridge, Massachusetts
Client: Skidmore Owings & Merrill
PM: Morris Levy
Date: Completed in mid 1980s.

First slurry wall to be used for both permanent and temporary conditions for rapid transit tunnel in the U.S. Project included approximately 300 meters (1,000 feet) of tied back slurry wall for excavation depths of 17 m (55 feet). Excavation was as close as 2.1 m (7 feet) to historic Harvard University structure founded on shallow spread footings. Deformations were typically maintained at less than 6 mm (1/4 inch) horizontal and vertical.

Post Office Square Park and Garage

Location: Boston, Massachusetts
Client: Friends of Post Office Square, Inc.
Role: PB was retained as the lead firm to provide design services for a seven-level parking garage in the middle of Boston’s financial district.
PM: Eldon Abbott
Date: Completed in 1990.

Project included excavating the deepest excavation to date in the Boston area, approximately 25 m (80 feet), with adjacent buildings typically located on shallow foundations. Most adjacent structures were within 15 m (50 feet) of the excavation. Construction used the top down method, soil profile included deep, soft clay deposit, approximately 335 m (1,100 feet) of slurry wall, permanent underdrain system, no reported damage to adjacent structures.

Boston Crossing Project

Location: Boston, Massachusetts
Client: Campeau Massachusetts Inc.
Role: PB was retained to provide a range of planning, design and permitting services.
PM: Andrew Boyd
Date: Completed in 1989.

Project included a slurry wall location study.

Central Artery/Tunnel

Location: Boston, Massachusetts
Owner: Massachusetts Highway Department
Role: PB, as part of the Bechtel/ PB joint venture, is serving as management counsultant.
PM: Tony Lancellotti
Date: Scheduled for completion in 2004.

Downtown portion of the project includes approximately 7 km (23,000 feet) of SPTC slurry wall. The slurry walls will form the permanent walls of the highway tunnels, being excavated beneath the 6-lane I-93 viaduct as it remains in use. About a third of the length of slurry walls will be constructed under low head room. (see "Constructing Slurry Walls Under Low Head Room," "Slurry Wall Design Parameters," "Using SPTC Walls as Permanent Tunnel Walls," "Should Slurry Walls Be Part Of the Final Structure?")

MBTA Tunnel Ventilation Shafts

Location: Boston, Massachusetts
Client: Massachusetts Bay Transportation Authority
Role: PB provided planning, design, architectural/engineering, and construction-phase services.
PM: Bill McMenimen
Date: Completion date scheduled for 1996.

Thirty ventilation shafts and/or emergency exits at 30 locations along three existing transit lines. Slurry walls designed at some sites to minimize ground movement and avoid potential damage to the subway tunnel and nearby historic structures.

Long Wharf Vent Shaft

Location: Boston, Massachusetts
Client: Massachusetts Bay Transportation Authority
Role: Geotechnical study as part of investigation of condition of wharf and condition of granite sea walls for eventual rehabilitation of pier end into a public park.
PM: Eldon Abbott
Date: Completed mid 1980s.

Project included slurry wall construction on the Boston water front for an approximately 23-m- (75-foot-) deep excavation immediately adjacent to the existing MBTA Blue Line Tunnel. Construction included use of permanent soldier piles to accommodate cross-lot bracing that served as both temporary bracing and the permanent floor levels for the vent structure. It was necessary to buttress the Blue Line Tunnel with the slurry wall to maintain water control and the structural stability of the tunnel. This necessitated excavating and casting the slurry wall in contact with the existing unreinforced concrete tunnel.

North Station Parking Garage

Location: Boston, Massachusetts
Client: Massachusetts Bay Transportation Authority
Role: Lead designer
PM: Rich O’Brien
Date: Completed in 1993.

Approximately 520 m (1,700 feet) of slurry wall construction employing top down scheme and permanent underdrain. Excavation was approximately 18 m (60 feet) deep through primarily organic soils and located 1.2 m (4 feet) off the existing Boston Garden Arena. Excavation extended 9 m (30 feet) below the foundation of the existing Garden, which maintained operations throughout the construction. (see "Tips for Slurry Wall Structural Design")

North Station Super Station

Location: Boston, Massachusetts
Client: Massachusetts Bay Transportation Authority
Role: Lead designers and providing construction phase support services in joint venture with STV Inc.
Project Manager: Rich O’Brien
Date: Completion scheduled 1999.

Project includes the construction of a new underground Green Line Station immediately adjacent to the existing Orange Line Station. Approximately 530 m (1,900) feet of slurry wall is under construction.

Greater Cairo Metro - Line 2/Phase 1

Location: Cairo, Egypt
Owner: National Authority for Tunnels (NAT)
Role: Greater Cairo Metro Consultants, a joint venture of PB, Electrowatt Engineering Services and Sabbour Associates, is providing design review and construction management services.
PM: Bob McDonald
Date: Phase 1A in scheduled for completion in October 1996 and Phase1B is scheduled for completion in September 1997.

Unreinforced cement/bentonite slurry perimeter wall box with an impermeable chemical grouted hard gel base plug beneath the jet grout treatment was used as supplemental ground water control in critical areas. (see "Cairo Metro Slurry Walls")

Santa Cruz Freshwater Bypass

Location: Santa Cruz, California
Client: City of Santa Cruz
Role: Landfill freshwater by-pass system feasibility study. Also PS&E and design services during construction.
PM: Lee Abramson
Date: 1996

Soil-cement-bentonite slurry cutoff walls were constructed to prevent subsurface migration of fresh water into the landfill. The walls are part of the solution to regulations that required fresh water to be intercepted above the landfill, conducted around it and discharged downstream of the landfill, back into the creek bed that the landfill occupies. (see "Slurry Wall Cutoff at Santa Cruz Landfill")

Los Angeles Metro Red Line

Location: Los Angeles, California
Owner: Los Angeles County Metropolitan Transportation Authority
Role: PB was a member of the Metro Rail Transit Consultants (MRTC) joint venture, which provided general engineering consulting services for the development of the Red Line.
PM: Krishniah Murthy
Date: All segments scheduled for completion by late 2001.

At the time of construction (1989) the slurry wall for the Metro Rail Union Station was probably a record breaker for depth in difficult ground—greater than 30 m (100 feet). The final wall contained 174 panels enclosing the 442-m- (1,450-foot-) long station. It was designed to provide complete water cutoff. Construction sequence called for skipping around so that nearby track yard activities were not interrupted. Extra finishing on interior faces was required for installation of an HDPE tunnel lining. (see "A Case History: Using Slurry Walls to Control Groundwater")