I-95/I-695 Preliminary and Final Design
Location: Baltimore County, Maryland
Client: Maryland Transportation Authority
Aerial view of interchange
JMT led the design of improvements to several miles of I-95 as
well as a complete realignment of the I-95/I-695 interchange, the
first highway transportation project in Maryland to implement
general purpose lanes and express toll lanes together in the same
facility.
JMT was responsible for Stage I and II Project Planning
engineering, environmental documentation and preparation of the
FONSI for the entire Section 100 project, refining all I-95 ETL
Section 100 alternatives. Subsequently, JMT was selected to
provide preliminary and final design for the $450 I-95/I-695
interchange, which was advertised in multiple contracts.
Final design included 11 lane-miles of Interstate 95, 12 lane-miles
of Interstate 695, 1 lane-mile of local roads and 16 lane-miles of
ramps. JMT coordinated the design with adjacent developers to
minimize impacts.
Highway Design: The preliminary design included
developing and analyzing multiple concepts for General Purpose and
Managed Lanes for I-95's mainline. In addition, JMT refined
multiple line and grade options for the I-95/I-695 interchange and
prepared the final design and geometrics of this complex interstate
interchange. The preliminary design encompassed an
array of design elements, which included horizontal and vertical
alignment, typical sections, developing and reviewing design
standards, and minimizing impacts to the existing ROW and
utilities. One of the unique challenges was the re-design of the
existing "double-braided" directional I-95/I-695 interchange to a
fully directional multilevel design with no ingress or egress ramps
from left lanes of the two mainlines. Complex MOT plans were
prepared to stage this interchange without disrupting the existing
traffic of nearly 200,000 ADT.
Traffic Forecasting and Engineering: JMT
performed travel demand forecasts for the various alternatives,
conducted travel time runs and performed traffic counts. In
addition, JMT performed capacity and operational analyses, studied
MOT options and evaluated constructability issues and evaluated
impacts to signing, lighting and ITS systems.
Structural Engineering: JMT prepared
preliminary layouts of bridge structures in a complex network of
multilevel interchange design at the I-95/I-695 interchange
involving many elevated structures for the directional ramps. The
preliminary structural design work included superstructure types,
span arrangements, pier locations and sizes and phased
construction. JMT is prepared final design for 22 bridges, 30
retaining walls, 6 noise barriers and 5 culverts at the I-95/I-695
interchange.
Geotechnical Engineering: More than 290
borings were required to satisfy the project requirements.
Our geotechnical investigations and evaluations culminated in the
development of a geotechnical report of findings and
recommendations for bridge foundations, retaining walls, noise
walls, pavement design, slope stability, storm water management
ponds, and utility directional drilling.
Additional Services: Preliminary and final
design included wetland and forest delineation, coordination with
environmental agencies (MDE, USACOE, MHT etc.), permitting
requirements, drainage and stormwater management, utility
coordination and relocations, hydrology/hydraulics analyses and
extensive public involvement and interagency coordination. JMT
utilized focus group meetings with agencies and communities to
establish the Purpose and Need, ARDS document and FONSI. Brochures,
displays and material for the I-95 Section 100 web page were
prepared.
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