|dc.description.abstract||Wisconsin bulb tee pretensioned concrete girders have being used for bridges. Their effective
spans to depth ratios and higher durability have made prestressed concrete girders desirable.
However, cracks were observed at the anchorage zones of these girders because of the
demand. To satisfy demand, these girders are heavily prestressed. Cracks initiate during
detensioning of pretensioned strands and grow more while transporting them to the resting
beds. These cracks create durability concerns as cracks lead aggressive salty water to the
steel strands, endangering structures’ stability. Especially, cracks in the bottom flange closer
to the strands are main concerns in this research. This research primarily focused on the
analyses of prestressed girder ends with modelling with nonlinear material properties to
understand and recommend control methods for girder end cracking.
The end zone behavior of the pretensioned girder was modelled using nonlinear material
properties. The concrete nonlinearity, strain softening and stress redistribution upon cracking
were also included in the behavior and the verification of tests were done by real tests on
these girders. Finally, the reasons for cracks were explained by examining the principal
tensile strain directions.
The results of previous study showed that debonding strands can effectively control cracking.
In this thesis, only debonding for cracking control method, therefore, was tested on 72W with
48 strands and 54W with 42 strands WI girders to see the real effect of debonding on
anchorage zone cracks. After getting good results from tests and verifying them with Finite
Element Analysis models, exact debonding percentages for other girders to eliminate cracks
were presented by giving results of FEA models built for each of them.||en