Chestnut Street Bridge

Location:

Coplay , PA
 

Precaster:

Northeast Prestressed Products, LLC, Cressona, PA
 

Owner:

County of Lehigh, Allentown, PA
 

Architect:

AECOM, Conshohocken, PA
 

Structural Precast Elements:

AECOM, Conshohocken, PA
 

Contractor:

Trumbull Corporation, Pittsburgh, PA
 

Construction Manager:

Pennoni Associates, King of Prussia, PA
 

Construction Inspection:

Pennoni Associates, King of Prussia, PA
 

Project Scope

Bridge Description:

3-span continuous bridge, five girder lines
 

Bridge Length:

1,124-foot
 

Precast Elements:

27 PS Bulb Tee Beams and 25 PS/PT Bulb Tee Segments (spans 4-6) (various sizes)
 

Key Construction Challenges:

  • Travel route for beam delivery
  • Record rainy summer 2018
  • Performing full-scale mockup of post-tensioning operation
  • Alignment and movement with drop in section between the two haunched girders.
 

Specifications & Details

 
 
 
 
 
 
 
Chestnut Street Bridge
Chestnut Street Bridge
Chestnut Street Bridge
Chestnut Street Bridge
Chestnut Street Bridge
 
 
 
 
 
 
 
 
 
 
 
 
 

Project Overview
Lehigh and Northampton Counties are currently replacing their 1930’s era bridge over the Lehigh River with a durable precast prestressed concrete structure. The Coplay-Northampton Bridge replacement has a $33.5 million price tag and will connect the two boroughs for motorists and pedestrians.

The replacement structure will be a three-span continuous bridge using pre-stressed bulb tee girders, with four splices along the span. The five girder lines will be post-tensioned and grouted with four tendons per line. A composite cast-in-place concrete deck will complete the structure.

The bridge is one of the most heavily traveled in the Lehigh Valley and so many people walk the bridge every day that the county is providing a shuttle bus six days a week for the duration of the project.

Precast Solution
Jason Beecher, PE, Project Manager at AECOM recalls that AECOM has been working on this project for more than a decade. Their memorandum of agreement with the County included architectural features on the replacement structure like ornamental lighting as well as reconstructing the tow path to service the old canal. Eventually all interested parties were satisfied and the project moved forward.

“AECOM was selected back in 2004 as the A and E for this design/bid/build project. We worked with the community to develop a durable structure for Lehigh County,” explained Beecher. They had to overcome community sentiment for the older structure by performing public outreach. The resulting concrete structure accommodates the addition of a turn lane as well as improving the durability and under-clearance. “The AECOM team were able to keep the existing pier locations in the river and through substructure evaluation determined they were adequate to support the new loading. “We didn’t have to put in coffer dams and minimized disruption to the fish migration seasons,” recalls Beecher. The use of the pre-stressed post-tensioned spliced girders was selected back in the TSL stage but it wasn’t until the design development stage that the FHWA showed interest in the project to test a new method of corrosion protection.

It’s Good to be First
This is the first project in Pennsylvania to utilize prestressed and post-tensioned bulb tee beam construction including the spliced girders. As well as the first project in the United States to use Electrically Isolated Tendons (EIT). The EITs allow for verification that the posttensioned cables have been encapsulated as per the plans and specs while they provide enhanced durability and non-destructive condition assessment over time.

The EIT uses technology that is readily available and has been successfully used in Europe. It requires only minimal changes to current construction practices and provides an incentive to improve workmanship. “The use of the demo EIT technology did not have an adverse effect on the project schedule or budget,” explains Larry Franco the Project Manager with Pennoni Associates. “I predict in the future this technology should be considered for every pre-stressed and post-tensioned project.” The EIT process uses a tight polymer duct that encapsulates the high-strength steel along with grouting that creates a protective alkaline environment for the steel strands and an anchor head that is isolated from the ground and the normal reinforcement of the structure. The use of electrically isolated anchorages allows the team to check the integrity of the plastic duct during and after construction and to monitor the corrosion protection of the high-strength steel during the whole service life with electrical impedance measurements. The Federal Highway Administration (FHWA) had been searching for a project that fit the criteria to demonstrate the EIT system. In conjunction with Lehigh County and PennDOT, the Coplay project was selected after vetting concerns about schedule, time and cost. Lehigh University and Dywidag Systems International (DSI) also played a part in this ground breaking project.

It’s Good to be First
This is the first project in Pennsylvania to utilize prestressed and post-tensioned bulb tee beam construction including the spliced girders. As well as the first project in the United States to use Electrically Isolated Tendons (EIT). The EITs allow for verification that the posttensioned cables have been encapsulated as per the plans and specs while they provide enhanced durability and non-destructive condition assessment over time. The EIT uses technology that is readily available and has been successfully used in Europe. It requires only minimal changes to current construction practices and provides an incentive to improve workmanship. “The use of the demo EIT technology did not have an adverse effect on the project schedule or budget,” explains Larry Franco the Project Manager with Pennoni Associates. “I predict in the future this technology should be considered for every pre-stressed and post-tensioned project.” The EIT process uses a tight polymer duct that encapsulates the high-strength steel along with grouting that creates a protective alkaline environment for the steel strands and an anchor head that is isolated from the ground and the normal reinforcement of the structure. The use of electrically isolated anchorages allows the team to check the integrity of the plastic duct during and after construction and to monitor the corrosion protection of the high-strength steel during the whole service life with electrical impedance measurements. The Federal Highway Administration (FHWA) had been searching for a project that fit the criteria to demonstrate the EIT system. In conjunction with Lehigh County and PennDOT, the Coplay project was selected after vetting concerns about schedule, time and cost. Lehigh University and Dywidag Systems International (DSI) also played a part in this ground breaking project.

Challenges
The engineering and transportation divisions of Northeast Prestressed Products (NPP) worked with Trumbull to overcome challenges in the development and delivery of the beams. Beam delivery met several snags as the travel route had to be adjusted so that the prestressed concrete beams – the longest = 139’-4” - could be backed down a narrow street to access the crane.

According to Franko, only one route had been deemed acceptable for the delivery of the prestressed beams. Unbeknownst to the team, a local township construction project impacted that route. “There was no other way to reach the staging area and we were looking at a possible six week delay,” said Franko. The team was able to devise a way to use a local street within the detour in conjunction with a public parking lot. That creative solution avoided major delays. Mother Nature poured buckets of rain on Pennsylvania in 2018. The year was one of the wettest on record, with the Lehigh Valley receiving more than 20 inches above normal, putting a damper on the construction schedule. “The causeways were frequently submerged due to the rain,” says Jason Beecher, PE, Project Manager, at AECOM. “Since they were needed to erect the prestressed beams, we had to increase the elevation to make sure they weren’t washed out”. The temporary causeway was designed based on the driest month of August, but with the extremely rainy summer the causeway was flooded and a concrete foundation had to be installed to support the temporary towers. Another obstacle for the team was performing a full scale mockup of the post-tensioning operation. Franko recalls it wasn’t easy finding a level space 600 feet in length that would mimic the exact bridge profile. The contractor found space that allowed the interested parties to walk through the process and satisfy PennDOT and FHWA.

As with any spliced girder project, there were some challenges. “There was some difficulty with alignment and movement with the drop in sections between the two haunched girders on opposing piers that were held in place only by the use of strong backs. The section between the piers was the farthest reach and that piece was difficult to maneuver. In order to avoid the PT ducts, we had to drop it down alongside and move it laterally in to place,” said Franko. There was a slight misalignment of the PT ducts due to the temporary forces on each end of the beams. They came up with a scheme to jack the beams to move everything within allowable tolerances.

Conclusion Lehigh University and DSI will continue to monitor this project and publish the results of this research. The results will confirm how well confined the post-tensioned tendons were during construction. The initial readings were above baseline and from that stand point the grouting operation was successful.

This non-destructive evaluation method monitors for breeches in the corrosion protection system indicative of the onset of corrosion. In this demonstration project the emphasis was for the EIT to measure quality control at the time of construction as well as long-term. The construction cost totaled $26M. The concrete deck work is scheduled for 2019 with the bridge opening in 2020.

Northeast Prestressed Products, LLC
121 River Street, Cressona, PA 17929
570-385-2352
Website: www.npp-llc.com
Northeast Prestressed Products, LLC maintains office, manufacturing and storage facilities on a 28-acre site in Cressona, Pennsylvania strategically located near major transportation arteries. The plant, with 80,000 square feet of fully enclosed production area, houses prestress and precast operations, as well as all support activities.

 
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