Long-term Evaluation of Prestress Losses in Concrete Bridges using Long-gauge Fiber Optic Sensors

Deterioration of infrastructure elements is expected during service life of structures, which necessitates monitoring of its condition. To this end, the overall objective of this research is the creation of a comprehensive suite of methods for the so-called Level III structural health monitoring (SHM) of prestressed concrete structures, where Level III SHM includes detection (Level I), localization (Level II) and quantification (Level III) of unusual structural behaviors, that can serve as the basis for the evaluation of structural health condition (Level IV SHM). The emphasis to long-term prestress losses stems from (1) the steady increase in the use of prestressed concrete in bridge construction in recent years (46% of bridges less than five years old), (2) the fact that they account for 42% of deficient bridges built five years ago or less, and (3) the adverse effect of unexpected prestress losses on the performance and integrity of a prestressed concrete structure. However, long-term monitoring of prestress losses is challenging due to (1) variable on-site conditions, in particular (but not only) temperature, that affect both the structure and the monitoring system, (2) rheological effects in the concrete and prestressing strands, such as creep, shrinkage, and relaxation, that interfere with mechanical effects and affect data analysis, (3) presence of pre-release cracks that affects the distribution of the strain in the structure, and also affects the data analysis, and (4) inherent uncertainties related to the reliability and accuracy of the monitoring system and the estimation of mechanical and geometrical parameters of concrete. The outcomes of the project are (1) the methodology for determination of long-term prestress loss using long-gauge fiber optic sensors, and (2) validation method for long-term temperature and strain measurements used for the analysis.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; References; Tables;
  • Pagination: 31p

Subject/Index Terms

Filing Info

  • Accession Number: 01712422
  • Record Type: Publication
  • Report/Paper Numbers: CAIT-UTC-NC-48
  • Contract Numbers: DTRT13-G-UTC28
  • Files: UTC, TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Jul 11 2019 9:48AM