Completion of the ongoing construction of the South Street bridge replacement in Philadelphia later this year is eagerly awaited by city drivers, since the bridge was closed to traffic in fall 2008 and detours have been in place ever since.
By then the original bridge was 85 years old, having opened in November 1923 and had become structurally deficient. It was in such bad condition city engineers reportedly did not feel it was strong enough to withstand the oncoming winter. At the time it was used by an average of 23,000 vehicles a day, restricted to a weight of 6 tons and under.
The $67.5 million contract for the job was awarded to Driscoll Construction Company Inc., of Spring House, Pa. Funding is split between 80 percent federal, 15 percent state, and 5 percent City of Philadelphia sources.
The project has experienced its share of difficulties.
“The majority of the issues or difficulties revolve around the job access. The bridge crosses numerous entities with strict access requirements. SEPTA requires all work to be performed during power outages. Since the rails are electrified, power must be de-energized prior to anyone accessing their property,” Driscoll project manager Chris Cooper explained. “The station — University City Station — is the final stop into and the first stop out of the Philadelphia airport. With that in mind, the window to perform work is limited to 1 a.m. to 4 a.m. The same issues extend across the Amtrak lines and the I-76 Schuylkill Expressway. All provide limited access windows to perform work.”
“CSX’s access has been restricted, but all work has taken place under the supervision of a qualified CSX flagman. He is in contact with the train yards and allows us crossing access between trains. Cooperation is key, and so far no major issues have arisen. Access was also limited where the bridge crosses the Schuylkill River. Great coordination took place during the demolition and erection of the bridge with the U.S. Coast Guard, which put out various bulletins to the local mariners. The navigable waterway needed to remain open at all times,” he added.
Additional challenges included transportation of workers, materials and equipment to the river piers, for which numerous barges, work boats and push boats were employed.
“At one point during the early spring, after a particularly heavy rain storm that added to the massive snow melt and run off, the river’s water level rose quickly and was moving at such a quick pace that a Sunday morning emergency occurred requiring large tug boat assistance to ensure the massive crane barges did not break free from their spuds,” Cooper recalled.
During construction of the piers located between the I-76 east- and westbound lanes, called the HUB, Driscoll created access to this area off the ramps. Prior to construction, this area could only be accessed by boat or during lane closures on the I-76 Schuylkill Expressway, but since this location was now easily accessible, Pennsylvania Department of Transportation (PennDOT) officials inspected the condition of the ramps and discovered extensive deterioration.
At press time, Driscoll was performing selective demolition to uncover the extent of the deterioration and the repairs will follow upon determination of the scope needed.
The job includes demolition, removal and complete reconstruction of the existing structure carrying South Street over CSX freight lines, the Schuylkill River, I-76 east- and westbound, University of Pennsylvania athletic fields, Amtrak Northeast Corridor tracks and SEPTA regional rail lines.
The project’s eastern and western limits are approximately half a mile in length, or basically from 33rd Street to 27th Street.
“The new construction includes a multi-span bridge, with reinforced concrete piers, abutments and retaining walls, all supported on approximately 22,000 linear feet of 14 x 102 piles. The only reused portions of the existing structure occur in the river, where the river pier foundations were partially removed and reused,” Cooper noted.
“Other contract work includes architectural traffic barrier and fencing, special protective railroad barrier, enhanced lighting, street and navigational lighting and decorative handrail lighting,” he added.
“Additionally, the project limits will receive new signing, signals, pavement markings, bridge approach slabs, roadway paving, curbs, sidewalks, drainage structures and sewer systems. New conduits will also transverse the bridge carrying AT&T, Philadelphia Electric Company [PECO], and University of Penn power and communication lines.”
Currently, Driscoll is erecting the final pieces of structural steel on the east side of the project. The deck work is progressing from west to east and is completed from the west abutment to approximately the west bank of the Schuylkill River. The project consists of 12 bridge spans while the concrete deck has been placed on eight. Sidewalk installation has been completed across five spans and is continuing behind the deck placement operation. Immediately following will be installation of handrail.
In addition to the construction of the elevated bridge structure, Driscoll continues to work on the approach slabs. This includes complete reconstruction of the roadway, all wet and dry utilities, sidewalk, curbs, retaining walls and paving as well as the complete removal of existing trolley tracks, which are no longer in use and date back to the early 1900s.
“Work continues on the tie-in sections of the I-76 access ramps. This includes installation of precast box beams, formed, rebar installed, and concrete roadway and barrier placement. Currently both east- and westbound ramps have their box beams installed, deck is formed, and rebar installation is under way,” Cooper said.
The project will involve:
• 12,800 cu. yds. (9,786 cu m) of new concrete
• 5.4 million lbs. (2.4 million kg) of structural steel
• 2.5 million lbs. (1.1 million kg) of rebar
Driscoll received notice to proceed on Dec. 3, 2008. The scheduled completion date is Sept. 10, 2010, but currently the contract is slightly behind schedule due to severe winter weather. The estimated time of completion is Oct. 30, 2010. CEG
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