详情

Design, Fabrication, and Construction of Long-Span Precast Pretensioned Girders Made with 0.7" Diameter Strands

项目名称：	Design, Fabrication, and Construction of Long-Span Precast Pretensioned Girders Made with 0.7" Diameter Strands
摘要：	Long-span bridges are often used in environmentally sensitive terrains, water crossings, and in locations with traffic and geometrical restrictions. Bridges with long-span precast pretensioned girders are advantageous due to their ease and speed of construction, lower cost, and long-term durability. The applicability of current bridge design and construction specifications for longer span prestressed girders is uncertain. Introducing the 0.7″ strands will help bridge designers extend the spans of the current beam shapes as well as any future development. This larger strand helps by increasing the possible area of prestressing steel and by lowering the centroid of the prestressing force, which enhances the eccentricity of the force and effectiveness of the prestressing steel. Research is needed to examine the applicability of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Design Factor (LRFD) Bridge Design and Construction Specifications for long-span precast pretensioned girders. This research shall thoroughly address design issues, fabrication, shipping, and handling of long-span precast pretensioned girders. To incorporate the 0.7″ strand in the AASHTO LRFD Bridge Design Specifications, research is needed to determine the transfer length, the development length, the strands spacing, and the minimum concrete release strength. The objective of this research is to summarize the current practice and augment the AASHTO LRFD Bridge Design Specifications (BDS) on the use of long-span precast pretensioned girders. The objective also includes developing specifications to incorporate the 0.7″ strands in the BDS. This research should include instrumenting long-span precast pretensioned girders during all phases of fabrication and construction and comparing the measured strain at the end zones, prestress losses, deflections, and cambers with the calculated values. This research addresses issues in several of the areas identified as program objectives in the 2013 Strategic Plan for Bridges and Structures developed by the AASHTO Highway Subcommittee on Bridges and Structures. The objectives addressed in this research are: Accelerate Bridge Delivery, Optimizing Structural Systems, and Maintaining and Advancing the AASHTO Specifications. Increasing the spanning capabilities of precast girders is expected to have a large impact on reducing the bidding cost of current superstructure options for long-span bridges as it will provide a competitive alternative to steel solutions.
状态：	Proposed
资金：	600000.00
资助组织：	National Cooperative Highway Research Program
项目负责人：	Dekelbab, Waseem
开始时间：	20150805
预计完成日期：	0
实际结束时间：	0