Implementation and Field Evaluation of Pretensioned Concrete Girder End Crack Control Methods

Quarterly Reports Other Documents Final Report
Final Report

Primary Investigators

Mike Oliva, Ph.D.
Professor, Civil and Environmental Engineering
University of Wisconsin-Madison
oliva@engr.wisc.edu

Abstract

Wisconsin bulb tee girders and girders in other states experience characteristic cracking at girder ends during de-tensioning and during lifting from the forms. These cracks pose durability concerns as corrosive agents can reach steel reinforcement or strands through these cracks, increasing long term maintenance costs, and potentially compromising structural capacity. This proposal outlines an approach for deploying selected crack control methods into Wisconsin practice. The success of crack control methods will be evaluated by measuring strains and crack sizes in girders built with control methods and by visual observation of girder ends for cracks during fabrication and erection. Phase II work is critical to implement a solution for the end cracking.

Objectives

The proposed Phase II study aims to examine control methods for crack widths, number of cracks and actual strains by field implementation and monitoring. The primary objective is to develop details of crack control methods to a field proven level which makes them ready for implementation, and to develop revisions to the Wisconsin standard plans for W54, W72 and W82 and prepare a draft section on crack control strategies to be added to the Wisconsin Bridge Manual (WBM).

Tasks

  1. Select crack methods
  2. Coordinate the construction and instrumentation of girders
  3. Monitor girder cracking before, during, and after de-tensioning
  4. Evaluate the impact of each method
  5. Compare the results and update finite element models, if necessary
  6. Explain discrepancies between FEA and field measurements
  7. Document chances in cracking
  8. Substantiate the crack control method
  9. Revise standard plans, draft section of WBM, and prepare final report

Project Information

  • Duration: 18 months
  • Dates: 7/1/2014 – 12/31/2015
  • Budget: $75,000 (match funds)
  • Student Involvement: One graduate student
  • Modal Orientation: Highway
  • Project ID: CFIRE 09-22
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