Tuesday, July 22, 2014
Location: Hackensack, NJ
Designer: Parsons Brinckerhoff, Inc
This project included the rehabilitation and widening of the Route 17 Northbound Bridge (NJDOT Structure No. 0214-150), over Interstate I-80 and Ramp K in Hackensack City, Bergen County, New Jersey.
The original bridge was constructed in 1962 and carried three lanes of northbound traffic, serving approximately 47,000 vehicles daily. This 455 feet long structure consisted of five (5) simply supported steel multi girder spans and crosses over local and express roadways of Interstate I-80 westbound and eastbound and one on- Ramp (Ramp K) to I-80 eastbound. The crossing is sharply skewed with a maximum skew of 67 degrees and the bridge deck and roadway are located on a compound horizontal curve to the west or left and variable deck superelevation, from 0% at the south end to 6% maximum at the north end. The main curve radius of 800 feet transitions to 10,000 feet through multiple compound curves.
The bridge was classified as Structurally Deficient due to the poor condition of the deck slab and also considered Functionally Obsolete due the inadequate bridge roadway width, with a Sufficiency Rating of 48.0. Prior NBIS bridge inspections had noted several deficiencies such as the poor condition of the deck and areas of severe rusting and section losses at the stringer ends and bearings, and inadequate geometry.
The rehabilitation included replacement of the existing deck slab and the entire superstructure including bearings, widening the bridge to accommodate an additional exit only lane on the left, safety improvements, roadway and drainage improvements. In order to maintain the existing vertical clearance, shallower beams were used in a continuous span unit. The new superstructure and deck were designed using LRFD. The existing substructure units that were retained were analyzed for HS25 Live loading, and the existing abutment bridge seats and pier caps were raised to accommodate the shallow superstructure.
The design and construction of the superstructure replacement and widening of this five-span sharply skewed horizontally curved bridge in a highly congested area posed many design and construction challenges, such as maintaining traffic on Route 17NB and I-80 during construction, girder erection and deck pouring, detailed field verifying and modeling the complex bridge geometry, complex steel framing, flared girder spacing ,seismic analysis/ design, erection of over 910,000 pounds of structural steel and cross-frames over 9 lanes of Interstate 80, placing girders with large non uniform cambers and web layovers and field fit-up. This two staged construction was completed in 2013 and the bridge is not classified as Structurally Deficient anymore. The improved Bridge deck width eliminates the previously inadequate deck geometry , hence the Functional Obsolescence is removed. The sufficiency rating of the rehabilitated bridge is expected to be over 80.0.
Rama Krishnagiri is a Senior Supervising Engineer and Professional Associate with PB, and is licensed in NJ, Pa. and NY. Over 30 years he has led many bridge design, inspection and rehabilitation projects for NJDOT, NYDOT, NJTA, Pa Turnpike Authority, and several counties in NJ. Rama’s bridge design experience includes fixed bridges, complex bridges and movable bridges. He is also experienced in Bridge Scour analysis and design. Rama has presented several technical papers at the International Bridge Conference, World Steel Bridge Alliance Conference, NJDOT/Rutgers Movable Bridge Conference Ocean County Society of Professional Engineers and published papers in Civil Engineering, ASHE and PB’s journals.
Mr. Skrobacz is a Supervising Structural Engineer with PB and has 30 years of engineering design and Inspection experience and serves as a lead structural engineer and project manager on both large and small multidisciplinary projects throughout the USA & Canada. Ed’s expertise is with design, inspection and rating of fixed and movable roadway and railroad bridges. Ed joined PB in 1991 after working at two other engineering firms and a Construction Company. Ed has served as an adjunct instructor at NJIT and is currently instructing Senior Design at Stevens’ Institute of Technology. Ed is actively involved with several Professional & Charitable organizations. Ed has prepared and presented several technical papers. Ed holds an AAS, BSCE & MSCE and is a licensed Engineer in NJ & PA.