Dover Bridge Replacement Project

The 83 year old Dover Bridge is getting a sidekick to bear the traffic loads while it gets a facelift and remains in place after construction for historical purpose. A modern 2,021-foot long, 44-foot wide, 50-foot high fixed span bridge along MD 331 over the Choptank River will span between Talbot and Caroline Counties, Maryland. The new bridge will feature concrete granite lined river foundations supported by 48-inch steel pipe piles. The substructure will have hammerhead caps and columns with architectural concrete that features marshland and wildlife accents. The superstructure will consist of haunched structural steel girders over the river and adjacent spans. The approach spans over the marshland will be founded on 36-inch steel pipe piles with concrete caps and prestressed concrete girders.

The work on the bridge forges ahead. The new embankment emanating from the Caroline County side is well underway. The visible drainage blanket sits atop a separation geotextile with approximately 8,000 wick drains drilled down into the marsh muck beneath it. June 12, 2015 this embankment entered into its first 150 day quarantine period during which the marsh muck converts into a peat base as the water is wicked out. This peat base is more structurally sound. In November two applications of high-strength woven geotextile topped with select borrow will be placed one on top of one another and the embankment will enter another 150 day quarantine period. Work is progressing on the piers with #1, 4, 5, 6, 7, and 8 being most visible. Work on the sediment trap and future Storm Water Management pond is underway. The video has a comparison shot of the project and this method of comparison will be used in subsequent releases.

 

The Dover Bridge project is at the end of its first quarantine period.  The Omega trestle has been extended to allow work on pier 12.   Piers 1, 4, 5, 6, 7, and 8 were previously visible but are now in various stages of completion.  The pile for 9, 10, 11, and 12 are visible.   Pier 3’s base is being constructed.  Cofferdams are being utilized throughout the project to limit the area of disturbance during the construction of the piers.  As the project comes out of the first quarantine period, work resumes on the embankments at both ends of the project.  The future wetland mitigation site in Caroline County is under development and the harvested materials are being used in various locations on the project.  Pier 3’s column is formed up and readied for concrete.


The Dover Bridge is now in its second quarantine period as the embankments continues its consolidation process as layer after layer of high-strength geotextile and select borrow brings the grade up to specification.

Much of the work is focused on preparing the piers to receive the girders.  All the work is greatly simplified in this environmentally sensitive area by the trestle which allows workers, materials and cranes easy access to the individual piers.  Now three cranes are working off the Omega trestle platform.

Pier 3 is being readied for its girder pedestal to be constructed and pier 2 has broken the surface of the water.  The overall shape of the bridge is very visible.   The first steel girder is delivered to the job.  There will be a steady supply of haunched and constant depth steel  girders arriving at the job during the month of February.

As February comes to an end, the Dover Bridge is truly becoming a bridge following the installation of some of the horizontal girders.  In less than a month project manager Jay Musser and his team have bolted together 23 girder segments and installed bladders on top of piers 4, 5, and 6.  Pier 2’s water line pier cap is being outfitted with a granite masonry facing to resist the harsh environment associated with being located in the channel.  Pier 3’s hammer head pier cap is curing and once strengthened sufficiently will have girders extended out from pier 4 and placed on top.  The embankments are still in their second 150-day quarantine period which will conclude on May 17 2016.  After the quarantine period David A. Bramble, Inc. will place additional select borrow to further raise the grade to meet the desired elevations.  The lines of the bridge are now clearly defined.

As of April 15, 2016 the project is about one month away from the end of the second 150-day quarantine period for its embankments.  14 prestressed concrete girders have placed on the pedestals atop piers six, seven, eight, and nine.  “The Baltimore,” McLean’s heavy capacity floating crane is rigged and has guy wires attached to a concrete girder ready to hoist it over to the Omega Trestle.  The trestle will provide conveyance of the concrete girder along the bridge well above the environmentally sensitive Choptank River basin.  Pier two’s encasement is being filled with concrete.  Once hardened, its girder pedestal will be constructed.  Work is well underway on the Talbot County abutment.  Split screens show the magnificent amount of work hat has taken place over the last ten months.

Fourteen months of highly orchestrated construction has resulted in a transformation that is hard to imagine without witnessing it firsthand.  The Dover Bridge series continues with the seventh installment.

The substructure of twelve piers and two abutments are nearly complete with only the Caroline County side abutment left to be constructed.  The embankments are now in their third 150-day quarantine period while incrementally layers of select borrow is added after each period.  After another layer, the forth quarantine period will take place, then the final layer followed by an eight-month long quarantine period.

The superstructure consisting of:

  • Twenty-five haunched steel girders over the river portion of the bridge weighing nearly three million pounds.
  • Thirty-five prestressed concrete girders spanning the approach from the Caroline County side weighing three and a half million pounds.
  • Thirty special sized steel girders weighing an additional one and a half million pounds.

totals nearly eight million pounds, or four thousand tons!

A compressed video documenting the placement of the last segment of girders from the Talbot County end abutment to the existing superstructure demonstrated the choreographed precision movements needed to position the girder in place with just 1/32 of an inch of tolerance.  They make it look easy.