DESIGN AND CONSTRUCTION OF THE LONGEST HPC GIRDERS FOR HIGHWAY BRIDGES IN NORTH CAROLINA

摘要

High performance concrete (HPC) has been used in the building industry for many years. In recent years its application in highway structures has received increased attention. This is due to the enhanced durability and strength characteristics of HPC, which can provide economical bridges with longer life expectancies. HPC is generally defined as a concrete which meets increased strength and enhanced durability characteristics. Increased flexure strength allows for the design of longer spans, wider girder spacings and shallower members. This in turn can lower initial costs by using fewer girders and piers. North Carolina Department of Transportation (NCDOT) has been one of the leading agencies in research and utilization of HPC. Since the mid 80's several investigations relative to HPC have been completed at North Carolina State University (NCSU). These investigations provided essential information for NCDOT to extend its bridge design practices using HPC. NCDOT has presented its design and construction experiences with HPC in many previous Regional HPC Showcases sponsored by the Federal Highway Administration. This paper's goal is to discuss the structural efficiency, and cost effectiveness of using 8,000-psi (55.2 Mpa) high performance concrete for a 115 foot (35.1 meter) Type IV AASHTO girder bridge. As the Type IV AASHTO girders for the bridge are the longest of this type girder in North Carolina, the authors will discuss the challenges during fabrication, transportation and erection as well as the design.