PennDOT Rebuilds Bridge Faster, Prettier
by David R. Zangrilli, Urban Engineers, Inc.
For thousands of tourists, Fruitville Pike is the most direct connection between U.S. 30 and historic downtown Lancaster. The Fruitville Pike Bridge carries PA Route 72 over Amtrak on the north side of Lancaster. Built by the Pennsylvania Railroad 75 years ago, the existing bridge was a two-span, two-lane, through girder bridge with a cantilevered sidewalk on the east side. Through years of service, the bridge had reached the end of its life.
The replacement bridge is also a two-span structure, with adjacent concrete box beams, providing two traffic lanes and a bicycle lane in each direction as well as a five-foot wide sidewalk on the east side. Four new mechanically stabilized earth (MSE) retaining walls allowed the roadway to be widened with minimal right-of-way acquisition. The project included new drainage, paving, sidewalks, signing, lighting, and traffic signals. When PennDOT opened bids on June 20, 2002, Allan A. Myers, of Worcester, PA, was the low bidder on the project at just under $5.9 million.
The original two-year construction sequence called for traffic to be maintained on the existing bridge while the new northbound lanes were constructed. In order to provide clearance for the construction of the northbound half of the new bridge, the existing sidewalk and a small portion of the existing pier were to be removed. Traffic would then be switched to the new northbound side, the existing bridge demolished, and the new southbound lanes constructed.
Myers commenced construction in August 2002, following the as-bid sequence. In early November, as Myers was removing the small portion of the existing pier, cracks developed in the existing crash wall and pier cap. PennDOT directed Myers to halt demolition, monitored the cracks, and speculated about the possible causes. The cracks continued to widen and on November 11, PennDOT closed the bridge to traffic to avoid possible catastrophic failure. PennDOT and Myers negotiated an acceleration agreement which called for one lane of traffic in each direction to be restored to the new bridge by Memorial Day 2003, and for the entire project to be completed by October 31, 2003.
PennDOT and Myers held several meetings during November and December 2002 to work out the details of the demolition procedure and the traffic detour. Myers subcontracted High Steel Structures, Inc. to remove the bridge superstructure. High dismantled the deck and most of the floor beams in late December, followed by the main girders and remaining floor beams in early January.
After Myers toppled the existing pier on January 17, it was discovered that the concrete for the pier crash wall extended only 18 inches below grade to the top of approximately two feet of dry rubble masonry. Although this marginal foundation was sufficient to support the bridge during its 75-year life, it was the most likely reason for the cracks which developed during demolition.
Myers’ crews worked more than 50 hours per week from January through May, in some of the worst winter and spring weather in recent years, to open one lane in each direction on May 22.
Community involvement can make a big, positive difference on a project, if done correctly. Originally, the replacement bridge was designed to look like the majority of other bridges in the state: a non-descript gray. But after the project was underway, a group of local citizens interested in aesthetic enhancements to the bridge and retaining walls contacted PennDOT.
The group included a state senator, a state representative, a Lancaster County commissioner, a member of the Lancaster County Planning Commission, and two members of civic improvement organizations. At a September 2002 meeting, PennDOT and the civic group agreed on numerous enhancements: using an additional color of anti-graffiti coating; adding a decorative detail on the inside face of the parapets; anodizing railings and barriers; and adding decorative lighting.
The civic group proposed using colored concrete for the MSE retaining wall panels. Instead of colored concrete, PennDOT changed the color of the anti-graffiti base coat from tan to brick red. Following the original design, the outside face of the parapets would remain tan.
For the decorative detail on the inside face of the bridge and retaining wall parapets, PennDOT selected a brick-embossed form liner. On the east side of the project, adjacent to the sidewalk, the form liner stopped three inches from the top and bottom of the parapet wall, providing a smooth border to frame the brick pattern.
On the west side, the form liner was limited to the upper face of the safety shape barrier, again with a three-inch smooth top border. To maintain the structural integrity of the parapets, PennDOT added approximately one inch to the thickness of both parapets. Adding the form liner required the parapets to be cast in place, instead of slip-formed as Myers had bid.
Myers’ subcontractor, LZ Painting, used brushes to apply a red anti-graffiti base coat to each individual brick in the form liner area. The mortar joints were painted with only clear antigraffiti coating allowing the gray concrete to show through, contrasting with the red bricks.
The project was designed with an Amtrak standard aluminum protective barrier on the bridge, single-tube PennDOT hand railing on the retaining wall parapets, and PennDOT pedestrian railings along the sidewalk at the ends of the parapets on the east side. PennDOT and the civic group agreed on a black anodized aluminum finish for the barrier and the railings.
The fourth request from the civic group concerned the addition of decorative lighting to the project. PennDOT arranged for PPL, the local electric utility company, to furnish and install 18 poles identical to those in Lancaster’s historic district. Myers installed the conduit, wire, and anchor bolts for the poles.
“Community involvement in any of these projects is a good way to go,” says Larry Hoffman, a District 8 construction services engineer with PennDOT and based in Harrisburg. “And now that the bridge is complete and the design a big hit, they now want to approach other bridges in Lancaster County the same way.”
David R. Zangrilli is a Construction Manager with Urban Engineers, Inc., Mechanicsburg, PA, and a Past President of the Harrisburg Section of ASHE.
This article is reprinted by permission of Constructioneer magazine, serving the region since 1945, and one of the 14 Associated Construction Publications published by Reed Construction Data.
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