Title: Transverse Prestressing of Bridge Columns for Seismic Retrofit and Repair

Author(s): Murat Saatcioglu

Publication: Symposium Paper

Volume: 358

Issue:

Appears on pages(s): 87-105

Keywords: Concrete columns, confinement design, hysteretic behavior, seismic design, seismic retrofit, seismic repair, shear design, splice deficiency, transverse prestressing

DOI: 10.14359/51740232

Date: 9/1/2023

Abstract:
Reinforced concrete bridge columns built prior to the enactment of seismic design and detailing requirements of modern codes of practice are vulnerable to seismic damage due to i) insufficient shear strength, ii) lack of concrete confinement and buckling of compression reinforcement, as well as iii) improper splicing of longitudinal reinforcement in potential plastic hinge regions. An innovative bridge retrofit technology was developed at the University of Ottawa, consisting of transverse prestressing to overcome all three deficiencies. Tests of large-scale bridge columns with circular square and rectangular cross-sections, with a shear span of either 1.5 m or 2.0 m, were tested to develop the technology. The results indicate that transverse prestressing provides clamping forces to control diagonal tension cracks, provides additional shear reinforcement and lateral concrete confinement pressure. It also improves the performance of plastic hinge regions with insufficient splice lengths by eliminating or delaying reinforcement slippage. As a result, the performance of seismically deficient columns can be improved substantially by the technique employed. Design procedures were developed to overcome all three deficiencies. The same technique is shown to be also effective as a column repair strategy for columns that have suffered from seismic shear damage.