Bridges

Cover of Establishing Positive Moment Continuity in Prestressed Concrete Girder Bridges: Performance and Lessons Learned
Establishing Positive Moment Continuity in Prestressed Concrete Girder Bridges: Performance and Lessons Learned
  • Publication no: ABC2017-019-17
  • Published: 20 April 2017

Structural health monitoring (SHM) is employed to evaluate a prestressed concrete bridge continuity detail in a newly constructed bridge in Louisiana. The detail is capable of resisting positive continuity moments that develop due to long-term and secondary effects such as creep and thermal gradients.

Data from embedded and surface mounted sensors was recorded for about five years to investigate the behavior of the bridge under creep, thermal gradient, and live load effects. The 96-channel SHM system recorded temperature, strain, rotation, and elongation readings.

The field data was used to assess bridge continuity and to calibrate a creep model for implementation in numerical analyses using the finite element method. The calibrated model resulted in good agreement between predicted strains and observed field data over a 1,000 day period. A live load field test was also conducted for the three-span continuous prestressed concrete girder bridge. Finally, thermal effects on the structural behavior and the challenges they impose on SHM will be discussed.

It was observed that girder ends cracked due to stress concentrations resulting from positive moments. The paper covers details of the monitoring system and data preprocessing challenges. Conclusions, lessons learned, and recommendations stemming out of this research for implementation in new bridge construction in light of the SHM data and the calibrated finite element models for evaluating creep, thermal and live load effects will be presented.