Route 29 Tunnel Project
Larry McKinney, P. E.
A distant view of the Route 29 tunnel project from the Route
1 bridge gives the fleeting impression of a River Boat gliding
north along the Delaware River in all the grandeur and opulence
these magnificent ships represented from the historic days of
the Trenton waterfront. In a sense this is the vision that the
New Jersey Department of Transportation, The City of Trenton,
Mercer County and Community representatives had was to recreate
the vitality and economic resource that the Trenton Waterfront
once represented to each of the stakeholders in the project.
Towards this vision, the Route 29 tunnel and approach roadways
represent a prominent jewel in the overall plans for accomplishing
the numerous projects that include Waterfront Park home of the
Trenton Thunder, a Marina, an amphitheater, a linear Park, professional
offices, parking facilities and shopping areas and restaurants.
Construction of Route 29 on a new alignment along the Delaware
River would complete a vital transportation beltway around the
City of Trenton while providing the improved access essential
to movement of patrons of these waterfront establishments.
The project development for the Route 29 Tunnel and approaches
is led by NJDOT Capital Program Management Division under the
direction of Assistant Commissioner, Dennis Keck, P. E. and
Director Art Silber. Richard Gramlich, P.E. serves as the Program
Manager for the Department and Robert Davies is the Project
In summer 1997, many years of planning for the project with
community involvement culminated when the Department advertised
for the construction of the Route 29 project utilizing a modified
design build Contract delivery process based on preliminary
plans and specifications developed by the Department's consultant,
Gannett Fleming, (Hammonton, NJ office). The successful Contractor
was a Joint Venture of PKF-Mark III and Neshaminy Constructors.
The Joint Venture retained Frederic R. Harris, Inc. as their
design consultant for the planning, engineering and design services
for the project and construction phase services. Harris and
the Joint Venture employed numerous other sub-consultants including,
K S Engineers, Hatch Mott MacDonald, Phoenix Environmental Management,
Haley & Aldridge to mention a few. The construction designs
for the project developed by the JV and Harris were submitted
to Gannet Fleming which provided engineering review for the
DOT under the direction of Greg Milakovic, P.E., and Ed McMahon,
P.E. The review comments of Gannett were provided to the Department
for consideration and final approval. Likewise, shop drawings
developed for construction were reviewed by the JV and Harris
before submission to Gannett for checking and final sign-off
was made by the Department.
Michael Baker Jr. Inc.'s Princeton, New Jersey office was chosen
by NJDOT to provide Construction Management/Construction Inspection
Services for the project in June 2000. The project services
encompassed construction documentation, correspondence and document
management, community interaction, monitoring and reporting
work progress based on the approved CPM Schedules, claims avoidance
and resolution, construction orders, progress payments, and
project acceptance recommendations. NJDOT Materials Department
conducted materials tests for the project. Michael Brescia,
P. E., Construction Manager, leads these services for Baker.
Baker's team included: ACT Engineers provided Public Relations
Support and inspection assistance, Baker Environmental guided
contaminant issues and solutions, Sverdrup Parcel provided expertise
on Electrical/Mechanical/ITS Systems and Tunnel Operations,
and Hunt Engineers assisted with dispute resolution.
The project limits encompass about 2.5 miles in length starting
at the Route 29 Expressway/Route 129 interchange at the south
end and ending at the Amtrak Bridge at the northern limit of
the project. Two 12-foot roadway lanes and a 12-foot right shoulder
and 3 foot left shoulder are maintained in each travel direction
including through the tunnel section. The roadways are separated
by concrete barrier curb along the south roadway approach to
the tunnel structure. North of the tunnel the roadways are separated
by concrete barrier curb to a point where the median widens
near Waterfront Park. From this point, the roadways are on independent
alignments to the northern project limit.
The Joint Venture exercised available strategies under the
bid concept to provide economy of construction and long-term
value in the completed project. Some innovations used by the
design and construction team included high strength concrete
pre-cast sheet piles, post tensioned tunnel structure, and deep
dynamic compaction of weak existing rivers edge fill materials.
The final design concept adopted for construction facilitates
traffic demand design objectives for the urban roadway.
Construction designs and drawings were developed on a continuing
basis after construction commenced in fall 1997 and progressed
toward completion over the past four years albeit not without
overcoming some remainders of the once thriving industrial use
of the Delaware River front traversed by the project. Industry
uses of the rivers edge left numerous contaminants in the soils
that were properly identified and suitable dispositions through
treatment or off site disposal in controlled landfills were
made. The scope and extent of the soil contaminants both known
and discovered during construction led to considerable escalation
of Contract costs and corresponding adjustments to Contract
time associated with the clean-up and disposal activities.
Major utility relocation work was required to fit the proposed
roadway between Lamberton St. and the Delaware River. Approximately
2,800 feet of 72" and 600 feet of 96" reinforced concrete
sewer line and associated structures owned by the Trenton Sewer
Utility were constructed adjacent to the tunnel alignment. The
new lines were required to enable an equal length of 72"
sewer line to be abandoned and removed from within the tunnel
alignment. Some segments of the old brick sewer were abandoned
in place and backfilled with flowable grout. Numerous pole relocations,
electrical services, gas line relocations along the alignment
required close coordination with PSE&G over the duration
of the project as the construction phases unfolded. Trenton
Water Department facilities were adjusted as they were affected.
The Joint Venture chose to employ pre-cast sheet piles to serve
the multi-function purpose for tunnel structure bearing support,
roadway embankment support, and scour protection along the Delaware
River. The piles were jetted in, down to a predetermined elevation
and then driven to specified bearing based on designated blow
counts. The piles were keyed together to maintain wall alignment
and continuity. A cast-in-place pile cap was used where the
tunnel base slab does not bear on the sheet pile wall. River
cobbles were placed along the rivers edge to restore pre-construction
condition along the rivers edge and enhance appearance.
The JV to produce the depressed roadway profile alignment used
a variety of wall types. Pre-cast T-Wall was used along the
East Side at each tunnel approach to provide original ground
support. A unique soldier pile wall design was used for top
down construction due to site restrictions adjacent to a Utility
access road which parallels the Riverview Cemetery adjacent
to the south tunnel approach. An architectural Wall facing was
connected to the soldier piles by welded studs and was cast-in-place.
Conventional reinforced concrete retaining walls were used along
the ramp leading from Lamberton road to northbound Route 29
and at other locations.
The 2,300 foot cut and cover below grade roadway structure
was conceived by the JV as a tunnel in the northbound direction
and a section open to the river in the south bound direction.
Column bents support the southbound tunnel deck. A solid center
wall and east wall are utilized to create the northbound tunnel.
This approach provides a roadway section consisting of two twelve
foot width roadway lanes, a 12 foot right shoulder, and a 3
foot left shoulder in each direction of travel. The tunnel grade
is 0%. The travel lanes are constructed with 0.02 ft./ft. cross
slope and shoulder slope is 0.04 ft./ft. Drainage is collected
in a slot drain along the right edge of shoulder and is discharged
to a detention basin west of the north portal via a 24"
cast iron collector pipe. The tunnel base slab, solid center
and east walls, and the roof deck are post tensioned in the
longitudinal direction. The roof deck is also post tensioned
in the transverse direction. The tunnel was constructed in 23
segments. Fifteen segments approximately 103' in length are
constant section width as described above. Eight segments at
the north end of the tunnel vary in width and length to accommodate
an exit ramp southbound leading to Lalor St. and for U-turn
to northbound travel via a ramp entering the northbound roadway
from Lamberton St. The Contractor used a hydraulically operated
traveling form system fabricated specifically for the project
use to support the roof deck. The form systems utilized, and
sequencing employed, enabled tunnel production of one segment
at about two-week intervals during peak progress. Post-tensioning
of the structure reduced the required amount of reinforcement
steel in the structure and produced corresponding savings in
labor to place the reinforcement. Concrete placements ranged
from 650 CY for a roof segment to over 1100 cubic yards when
both base slab and roof deck were placed on the same day.
Life safety systems are provided within the tunnel in accordance
with 1998 NFPA 502 Fire Code. Three banks of three jet fans
are located along the northbound side of the roadway. No fans
are required along the southbound roadway since it is open to
the river. Call boxes, fire alarm pull boxes, fire extinguishers
and dry standpipes are spaced at approximately 300-foot intervals
for use in the event of an accident, breakdown, or fire incident.
Air quality monitors detect carbon monoxide levels and opacity,
and activate the jet fans to maintain preset reading levels.
A linear heat detection system is an additional fire detection
system installed in the tunnel that will report the location
of fires detected to Trenton Communications Division.
Traffic signals were installed at the Cass St. and Warren St.
intersections with Route 29 and at the intersection of Lamberton
St. and Lalor St. Epoxy and latex pavement striping, and thermoplastic
pavement markings were applied for roadway delineation and guidance.
Regulatory and guide signing was installed. Signs excluding
hazardous material loads from the tunnel are in place at each
tunnel approach. Temporary detour signs are installed on designated
detour routes for motorists and trucks to follow when the tunnel
is closed due to emergency or for tunnel maintenance.
Stationary, fixed focus, CCTV cameras are installed within
the tunnel to monitor traffic flow conditions. Pan, tilt, zoom
cameras are installed at each approach to allow view of the
tunnel entrances and the roadway intersections with Route 29.
NJDOT Traffic Operations South will monitor the CCTV. Fiber
optic cable connects the tunnel CCTV system into the NJDOT backbone
located on I-295. The video is also fed to the Tunnel Controls
Building, and NTOC. Tunnel ventilation equipment and life safety
systems are monitored and controlled via a PLC system located
in the Tunnel Controls Building at the intersection of Lalor
St. and Centre St. Fire and smoke control panels, ventilation
fan motor controls, un-interruptible power supply, and call
box controls, are located within the TCB. Transformers and standby
emergency generator equipment are located within the fenced
Dual PSE&G power supplies are provided to the tunnel from
the PSE&G's Liberty substation for redundancy required under
code. Either PSE&G feed will carry the full power demand
for the tunnel. The standby generator has capacity to provide
full operation of the tunnel systems for an extended duration.
Tunnel lighting is designed to provide four levels of illumination
at the portals through the transition zones from approach to
within the tunnel depending on the ambient light conditions.
The light levels are controlled by photoelectric cells located
outside the tunnel. Approximately, 1500 high-pressure 150 and
400 watt high pressure sodium light fixtures are used for tunnel
lighting. Dual quartz lamp fixtures are employed at the tunnel
entrances to provide partial roadway illumination levels during
restart of the sodium vapor lamps when power supply transitions
are experienced. Nighttime roadway lighting levels are maintained
by operation of approximately one quarter of the lights.
A linear park, designed by Vollmer Associates of New York City,
will be built on top of the tunnel under a separate construction
Contract planned to begin in 2002. The park will be complete
with playground, paths for walking, interpretive areas, and
manicured lawn areas, a pleasing sight for residents living
along Lamberton St., which parallels the Route 29 alignment.
An Open Water Mitigation Site is presently under construction
adjacent to Lamberton Road and along the Delaware River south
of the tunnel project. Upon completion, the site will meet permit
requirements for replacement of wetland areas required for construction
of the Route 29 project.
The Route 29 tunnel and approach roadway and the linear park
construction represent a significant investment in the future
of the City of Trenton area by the New Jersey Department of
Transportation. The facilities constructed will serve the immediate
and long-term transportation needs of the area and improve the
quality of life for the residential areas along the corridor
and the citizens of Trenton. The facility is a remarkable accomplishment
for the New Jersey Department of Transportation and the citizens
of the State of New Jersey. The Department opened the tunnel
and roadway on March 2, 2002 and the facilities have been well
received by commuters and through traffic.
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