WorldWide Drilling Resource

16 NOVEMBER 2016 WorldWide Drilling Resource ® Geotechnical Investigations at the Century-Old Portal Bridge Compiled by Editorial Staff of World Dril R s rc Wide ling e ou e ® The U.S. Transportation Department is spending $16 million on projects to prepare for replacement of the Portal Bridge, a key rail link along the Northeast Corridor for trains heading between New York and New Jersey. Total cost to replace the Portal Bridge over the Hackensack River in Kearny is estimated at $1 billion. The bridge, which carries 450 Amtrak and NJ Transit trains and 180,000 passengers a day, was originally constructed in 1910, and has become a major roadblock in the Northeast Corridor. The bridge, which swings open to allow marine traffic to pass below, is fre- quently criticized for delays when it malfunctions and doesn't close properly to allow train traffic to cross above. Wooden pieces of the bridge have even caught on fire in the past, bringing trains to a standstill in the corridor. "At 105 years old, the Portal Bridge has become the poster child for what happens when we fail to invest in our aging in-frastructure - major delays for thousands of commuters, lost time and money for businesses, and a drain on our national and local economies," said U.S. Senator Robert Menendez. The existing two-track railroad will be expanded to five tracks, and elevated to allow for the replacement of the existing swing bridge with two fixed bridges, one north and one south of the existing alignment. Gannett Fleming provided geotechnical services to design the replacement of 2.5 miles of the Amtrak Northeast Corridor. The east and west river-crossing approaches will be viaduct structures supported on driven-pile foundations. The new align- ment requires nine retaining walls, totaling more than 8000 linear feet. The multiphase subsurface investigation program included 360 test borings, wells, soundings, and in situ test locations. The subsurface investigation included cone penetrometer and dilatometer test soundings, as well as field vane shear, pressure meter, and rock bore- hole shear testing. Borings were performed using a combination of rigs mounted on truck, track, skid, and barrel float platforms, along with a jack-up barge for borings and soundings in the Hackensack River. Key features: • Highly compressible peat deposits • Compressible clay deposits up to 80 feet thick • Potentially liquefiable soil deposits • Very high axial and lateral bridge pier loads • Localized scour conditions in the Hackensack River • Large expanses of wetlands and shallow lagoons • Coordination with more than 20 property owners • Construction over several highly contaminated industrial properties and two existing landfills Senator Cory Booker said, "The overdue construction of a replacement for the Portal Bridge will help jump-start infra- structure upgrades throughout the region like the Gateway tunnels, create jobs, and make our state and regional economies stronger." & $ & & !' & "$!(! & ! % "$ & $ ( & % & #' % % ) & +!' ) $ ( ! !$,% ( %& *" $ % & !& ( & ! % % & $% " %" $ !( $ "$ % & & ! % !' &$ % " '% ) " +!'$ ' " !+ % &!& +