www.concreteproducts.com January 2015 • 63
FEATURE
COVER STORY
The gantry scheme proved its mettle during the frst prestressed
girder erection phase (eastbound structure, outer lanes). Each main
frame is shifted after a row of beams is placed on new piers. Ed
Kraemer & Sons confgured the gantry to bear equally on the exist-
ing structure and new pier, the latter via a temporary bracing and
mounting assembly (above). The method limits primary lifting re-
quirements to one main crane; more importantly, it enables a girder
erection sequence between new eastbound and westbound structures
such that the fnished bridge will have one longitudinal joint in-
stead of three on the original crossing.
Crews engage girders for hoisting by threading lifting plates through
top fanges, securing them with six bolts near the web midpoint.
County Materials is fabricating the 150- to 168.5-ft. bulb tees to
Kraemer's lifting-hardware specs and with up to 50 0.6-in. diameter
prestressing strand, 22 draped.
PHOTOS: Illinois Tollway