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Mid-America Transportation Center

Assessing the Damage Potential in Pretensioned Bridges Caused by Increased Truck Loads Due to Freight Movements (Phase 2)

Final Report
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Researchers

  • Principal Investigator: Robert Peterman (bob@ksu.edu (785)532-7612)
  • Graduate Students
  • Steven Hammerschmidt
  • Project Status
    Complete
    Sponsors & Partners
  • Mid-America Transportation Center
  • Kansas State University
  • About this Project
    Brief Project Description & Background
    This research is aimed at determining the existing stresses in a concrete member. The first step is to image the concrete in its in-situ stressed condition at a desired location, and then cut around the imaged area using a diamond core bit to a depth of approximately one inch. The result will be a "re-bounding" of most of the elastic strain carried by the concrete member at that point. By re-imaging the point after penetration by the core drill, the change in surface strain can be determined, and thus also an estimate of the initial internal stress. Phase 2 extends the work to pretensioned members with multiple bonded tendons.
    Research Objective
    Phase 2 will extend the technique to pretensioned members with multiple bonded tendons.
    Potential Benefits
    One of the most attractive features of this new measurement technique is that there is typically no surface preparation required. The reflective properties of the member's surface serve as a "fingerprint" of the unique location. Thus, an engineer or technician can begin taking initial baseline measurements within minutes after arriving at a bridge site.
    Abstract
    The proposed research is aimed at developing a procedure to determine the existing stresses in a concrete bridge member using non-contact strain measuring techniques. The first step is to image the concrete in its in-situ stressed condition at a desired location, and then cut around the imaged area using a diamond core bit to a depth of approximately one inch (actual depth and core diameter are being determined in Phase 1). The result will be a “re-bounding” of most of the elastic strain carried by the concrete member at that point. By re-imaging the point after penetration by the core drill, the change in surface strain can be determined, and thus also an estimate of the initial internal stress at that point. Phase 2 extends the work to pretensioned members with multiple bonded tendons.
    Project Amount
    $ 95,166
    Modal Orientation
  • Structures