Mitigation of End Zone Cracking in Prestressed Concrete Girders

Details

• Creators:
  Kim, Yail Jimmy
• Corporate Creators:
  University of Colorado at Denver
• Corporate Contributors:
  Colorado. Department of Transportation. Applied Research & Innovations Branch ; United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  Alloys Bridge Construction Cracking Girders Precast Concrete Prestressing
• Publication/ Report Number:
  CDOT-2024-12
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Colorado
• Corporate Publisher:
  Colorado Department of Transportation. Applied Research & Innovations Branch
• Abstract:
  This report presents two major aspects related to the end-zone behavior of prestressed concrete bulb-tee girders: i) laboratory experiments and ii) full-scale finite element modeling. The first part of the report discusses the behavior of anchorage zones, also known as end zones, with discrete rebars and continuous meshes. To examine the implications of various reinforcing schemes on the capacity, cracking, and failure of end zones, 50 block specimens are loaded and their responses are analyzed. While concrete splitting originates from local tension generated near the axial compression, the location of cracking is dominated by the path of stress trajectories related to the number of rebars, which is not recognized in the case of the meshed specimens. A two-stage analytical model is formulated to predict the magnitude of bursting forces and figure out the effects of several parameters on the response of the end zones. The applicability of existing design expressions is assessed and the need for follow-up research is delineated. The second part of the report deals with the effectiveness of various reinforcing schemes in the end zones of prestressed concrete bulb-tee girders. The default girder taken from the Colorado Department of Transportation includes C-bars and spirals, which are intended to control cracking, and three-dimensional finite element analysis is conducted. The formulated models are used to evaluate the breadth of end zones, strain responses, cracking patterns, damage amounts, and splitting forces, depending upon the configuration of the end-zone reinforcement. Whereas the short-term crack width of the girder may not be an immediate concern, its long-term width is found to surpass the established limit of 0.007 in. In this regard, multiple C-bars should be placed to address concerns about undesirable cracking.
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:624611935e86f8bbfb66e454f2cbfafe8af9f9218817214f82137bca5701cc20d8ccd0755ebb475962ce207b5bcaa2f935b6be68859b4596b45bdc3acf71e17c
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/83836/dot_83836_DS1.pdf
• File Type:
  [PDF - 4.85 MB ]