Transfer, Development, and Splice Length for Strand/Reinforcement in High-Strength Concrete. National Cooperative Highway Research Program

摘要

Article 5.4.2.1 of the 3rd edition of the AASHTO LRFD Bridge Design Specifications limits the applicability of the specifications for concrete compressive strengths of 10,000 psi or less unless physical tests are made to establish the relationships between concrete strength and other properties (AASHTO 2004). A comprehensive, article-by-article review of Section 5 of the AASHTOLRFD Bridge Design Specifications pertaining to transfer, development, and splice length for strand/reinforcement was performed under NCHRP Project 12-60 to identify all the provisions that have to be revised to extend their use to high-strength, normal-weight concrete up to 15 ksi. Upon completion of the experimental work under NCHRP Project 12-60, draft specifications and accompanying commentary for provisions to extend the application of the LRFD bridge design specifications to high-strength concrete were developed. The provisions cover the transfer and development length of prestressing strand and the development and splice length of reinforcement in normal-weight concrete with compressive strengths up to 15 ksi.