Baltimore

Key Players

Owner City of Baltimore, Dept. of Transportation

Lead Designer Whitney Bailey Cox & Magnani

General Contractor Joseph B. Fay Co.

Precaster Supplier Northeast Prestressed Products

Concrete Beam Erection Interlock Steelworkers

Landscaping F & F Landscaping

Pile Predrilling McCrossin Foundations Division

Replacing an 80-year old, two-span, filled-concrete arch structure with a 230-ft-long pre-stressed concrete beam bridge with an arch facade was challenging from the outset. There was an absence of as-built drawings for demolition work and extra coordination was necessary to avoid conflicts with an active rail line. More than 7,000 cu yd of concrete were poured for the substructure, including 4,200 cu yd on 1,000 ft of 48-in./30-in. caissons for the footings.

The center pier concrete pour was the largest of the project, using 730 cu yd of concrete and lasting more than 14 hours. Limited space precluded use of a crane, so an unusual skid beam system was used to launch and set 16 112-ft-long, 62-ton girders from each abutment, minimizing disruptions to rail traffic.

The new structure’s 12 18-ton precast arch pieces were cast in an upright position because of the rebar that needed to project from the top of each piece. Each rebar stirrup was bent to a different shape to accommodate the taper in each piece. A controlled shop environment facilitated the casting of embedded splice plates to a tolerance of only 1/16 in. The arches were shipped on flatbed trailers in an upright position because they could not be laid flat at their fabricated size with the rebar protruding from the ends.

As the precast arch segments were installed in the field, detailed engineering and surveying verified the proper alignment of the embedded splice plates.