Preservation of Hopkins Street Bridge via externally bonded prestressed CFRP laminates

Abstract

Several fascia beams of an existing prestressed concrete box-girder bridge, located in the City of Defiance, Ohio, USA were severely deteriorated due to the influence of de-icing salt applied during wintertime. An in-depth visual inspection and subsequent full-scale load tests were conducted to identify the extent of deterioration. A strengthening strategy was devised involving advanced carbon fiber reinforced polymer (CFRP) composite strips, post-tensioned via the Stress Head system that was developed and patented in Switzerland. The technique, the first of its type in the USA, offers numerous advantages over conventional repair and rehabilitation methods. The inherent attributes of this innovative approach include lighter weight for easy handling, lower loss of prestress due to higher initial tensile strain, corrosion resistance laminates, optimal use of high tensile strength of CFRP plates, optimal cost/performance ratio, and increased durability with reduction of crack width and tensile steel strain. The proprietary anchorage for prestressing the laminates, made entirely of CFRP composites, is the hallmark of this novel technique. The project, one of two bridges repaired utilizing this approach, was sponsored by the Federal Highway Administration (FHWA) through the Innovative Bridge Research and Construction (IBRC) Program. The IBRC Program promotes the use of new materials and construction techniques for the repair, rehabilitation, replacement, or new construction of bridges and other structures. The design and construction of the strengthening system, adopted to upgrade the Hopkins Street Bridge, will be presented in this paper.

Keywords:

• Fascia beams
• Box-girder
• Advanced carbon fiber reinforced polymer (CFRP) composite
• Post-tension
• Stress Head system
• Rehabilitation
• Strengthening
• Preservation
• Laminates

Acknowledgements

The authors wish to express their sincere gratitude to the following individuals for their significant contributions to various aspects of the present study: Mr Warren Schlatter, Defiance County Engineer; Mr Gaylon Davis, Chief Deputy Defiance County Engineer; Dr Bahram Shahrooz of the University of Cincinnati; Mr Brandon Collett and Ms. Lori Brinckman of Ohio Department of Transportation (ODOT); Mr Sean Gallagher, Mr David White, and Mr Reto Clenin of the Sika Corporation; Mr Patrick Plews of TranSystem; and Mr Tyson Herman and Mr Pete Wallace of Structural Preservation Systems Inc.; and Mr Michael Rath of Fort Defiance Construction and Supply Inc.

The present research project was sponsored by the Federal Highway Administration (FHWA) through the Innovative Bridge Research and Construction (IBRC) endeavor. The authors wish to acknowledge the financial support of the FHWA.