In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
American Concrete Institute
38800 Country Club Dr.
Farmington Hills, MI
Feedback via Email
Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Post-Tensioned Repair and Field Testing of a Prestressed Concrete Box Beam Bridge
Author(s): Andrew E. N. Osborn and H. Kent Preston
Publication: Special Publication
Appears on pages(s): 229-256
Keywords: box beams; bridges (structures); coatings; deterioration; epoxy resins; lateral pressure; loads (forces); load tests (structural); post-tensioning; prestressing steels; repairs; shotcrete; Construction
Abstract:Over 600 bridges composed of adjacent prestressed concrete box beams were built in the early 1950s in Pennsylvania. The box beams were placed side by side and had an asphalt wearing course on top. Span lengths ranged form 30 to 60 ft. Their design was very conservative by today's standards. The concretes used in these bridges have high chloride contents; water leaks down through the joint between box units and the strands often have inadequate cover. Thus, it is not surprising that many of the box beams are deteriorating due to corrosion of their prestressing strands. This project was directed toward developing economical repair schemes for these bridges. The literature survey did not reveal any schemes specifically applicable to adjacent box beams. Two external reinforcement repair schemes were developed and trial installations were made on a bridge near York, Pa. Both schemes included the removal of deteriorated concrete, placement of external reinforcement beneath the beam, and application of shotcrete to the soffit of the beam. In Scheme 1, the external reinforcement consisted of epoxy-coated reinforcing bars. This repair method restored ultimate flexural capacity but did not restore lost prestress. It was the least costly of the two methods. In Scheme 2, post-tensioned, epoxy-coated strand was used. This restored the full ultimate flexural capacity and most of the lost prestress. Difficulties were encountered in installing anchors for the post-tensioned system, but its performance was good. The bridge was tested after repair. The external reinforcements were found to be fully composite with the original beams. The tests also revealed the lateral distribution of wheel loads. In spite of the poor condition of the bridge, the wheel loads were well distributed laterally, leading to a structure that was stronger and stiffer than expected.
Click here to become an online Journal subscriber