The composite connection between a set of precast concrete
deck panels and supporting girders must be capable
of carrying significant shear and tensile forces. Traditionally,
this has been accomplished by engaging discrete
steel elements (reinforcing bars or studs) that extend from
the girder and pass through the haunch into the deck. The
field-cast grout would then provide geometric integrity to
the connection but would not resist applied loads by itself.
The discrete connector elements are commonly clustered
to limit the number of pockets in the deck panels. The
American Association of State Highway and Transportation
Officials’ AASHTO LRFD Bridge Design Specifications25
limit the distance between groups of clustered
connectors to no more than 24 in. (610 mm) in most cases.
Separate studies investigating the potential relaxation of
this spacing provision to facilitate the use of precast concrete
deck panels are under way.
To eliminate the fabrication, congestion, and assembly
problems associated with interlacing these girder connectors
into the numerous deck panel pockets, a novel concept
was developed wherein the sustained tensile capacity of
UHPC is engaged as a key structural element within the
composite connection system.26 The field-cast UHPC
engages discrete connectors both in the deck and on the
girder and, through its high sustained tensile capacity,
transfers applied forces between the prefabricated components