Project Challenge:
The Southeastern Pennsylvania Transportation Authority (SEPTA)
concluded that Bridges 5.03 and 5.03A located within the Main
Line portion of its Regional Rail system were in need of major
repair or replacement. The bridges carry daily commuter trains
from six of the seven Regional Rail lines over Wayne Avenue.
The location of Bridge 5.03 made it virtually inaccessible to
perform major repair of replacement. The bridge is located at
the south end of SEPTA's Wayne Junction Station and was built
inbetween Main Line Bridge 5.03A and Chestnut Hill East Line
Bridge 5.04. Bridge 5.03 is one on the heaviest traveled bridges
in SEPTA's entire system and could only be taken out of service
during short construction windows. SEPTA retained Klein and
Hoffman, Inc. (K&H) to lead a multidisciplinary team to
provide professional engineering services for
replacement of Bridge 5.03 and repair of adjacent Bridge 5.03A
from the investigation phase through design and construction.
Project Solution:
Existing conditions were evaluated, load rating analyses performed,
and alternative programs for rehabilitation or replacement were
developed. Alternative analysis included constructability analysis,
construction phasing and construction cost estimates that allowed
SEPTA to determine whether each structure needed to be replaced
or rehabilitated.
Once it was determined that Bridge 5.03 required full replacement
of the superstructure, maintaining rail service during construction
became the top priority. K&H developed an innovative strategy
to replace Bridge 5.03 in halves. The east half of the bridge
carried outbound rail traffic and nearby track interlockings
allowed for its replacement utilizing conventional construction
during an 8-week track outage while outbound rail traffic was
diverted across adjacent Bridge 5.03A.
The west side of the bridge carried inbound rail traffic and
the existing interlockings did not allow for diversion of rail
traffic across Bridge 5.03A. Consequently, the west half of
the bridge was replaced using "roll-in" construction
techniques. The new superstructure was constructed on a temporary
runway structure adjacent to the west half of Bridge 5.03 while
the rail line remained in service. Once the preparatory work
was complete,
a single 52-hour weekend track outage was used to demolish the
existing superstructure, roll and lower the new superstructure
into place, and restore the inbound track to service.
Repair of Bridge 5.03A was more straightforward. K&H engineered
reinforcement to strengthen the girders and designed a replacement
deck structure. In order to rehabilitate the bridge, rail traffic
was diverted onto the newly constructed Bridge 5.03 with no
interruption to revenue service.
CLIENT/OWNER: Southeastern Pennsylvania
Transportation Authority (SEPTA)
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