Rapid Bridge Construction Technology: Precast Elements for Substructures
Abstract
This thesis elaborates on the ongoing efforts of University of Wisconsin ? Madison
and Wisconsin DOT to utilize precast technology for bridge substructures in Wisconsin as a
rapid construction technique. Decreasing the negative outcomes of detours for the traveling
public and freight transportation during bridge replacement projects is the main advantage of
the precast construction in addition to improving work zone safety, allowing the use of
innovative materials, introducing better in plant quality control and lessening the
environmental impact. The use of precast concrete for bridge superstructures has long been
known and practiced. Various precast substructure elements have been used throughout the
world resulting in successful projects. After the better understanding of the importance of the
project time in replacement projects, Wisconsin also started to shift to accelerated
construction techniques. The last two projects, Baldwin Bridge on USH 63 in Croix County
of Wisconsin and Mississippi Slough Bridges on Wisconsin Highway 25 which use precast
substructure elements, clearly show these efforts.
After evaluating the characteristics of current cast in place abutments, piers, pier caps
and foundations, the components that are the most advantageous for precasting were already
determined and specific systems have been developed during a first phase of research
completed by Okumus46. Precast abutments and pier caps are observed to be the most
suitable elements for standardizing and are the focus of this research as well, which is the
extension of the first precast substructures project. Modules of reasonable weight under
permissible limit for Wisconsin and sizes, accordingly, are defined. Easy to implement
connection details with enough strength were identified for the systems. Standardization was
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given special attention to allow repetition, reuse of forms and provide familiarity of details
for contractors. Especially for this research, it is decided that the same bent cap system will
be used for piers, pile caps and in some abutments which will increase the repetitive nature of
the system. Through regular interaction with DOT engineers and the precast manufacturers,
alternative guidelines, design examples and standard plans are being prepared as end
products. It is believed that future projects such as the ones mentioned before, with precast
abutments will help improve the system more and show efficiency of precast substructure use
in Wisconsin and make both design engineers and contractors more familiar with the system
resulting in a lower project cost.