LRFD Minimum Flexural Reinforcement Requirements

According to the AASHTO LRFD Bridge Design Specifications, minimum reinforcement provisions are intended to reduce the probability of brittle failure by providing flexural capacity greater than the cracking moment. There was a concern with the current AASHTO LRFD minimum flexural reinforcement requirements, especially when applied to pretensioned or post-tensioned concrete flexural members. Increasing the nominal capacity of a member can result in increasing the cracking moment of the same member. This makes the design process iterative, and the current minimum reinforcement requirement for posttensioned segmentally connected members is difficult to satisfy. This also may lead to less efficient design of pre-tensioned/post-tensioned concrete flexural members. Provisions for the design of minimum flexural reinforcement must be suitable for all structure and reinforcement types covered by the AASHTO LRFD Bridge Design Specifications and should be consistent with the LRFD design philosophy.This report presents proposed revisions to the AASHTO LRFD Bridge Design Specifications minimum flexural reinforcement provisions for load and resistance factor design (LRFD) with detailed design examples illustrating the application of the proposed revisions. The proposed revisions are based on comprehensive analytical and large-scale testing programs for investigating the minimum flexural reinforcement requirements with consideration to scale effects. The research considered reinforced, pre-tensioned, and post-tensioned concrete flexural members (e.g., bonded and unbonded tendons for segmentally and other than segmentally constructed bridges).

• Record URL:
  http://www.trb.org/Main/Blurbs/179395.aspx
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/9780309480574
• Authors:
  • Sritharan, Sri
  • Wibowo, Hartanto
  • Rosenthal, Michael J
  • Eull, Jacob N
  • Holombo, Jay
• Publication Date: 2019

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; Tables;
• Pagination: 119p
• Serial:
  • NCHRP Research Report
  • Issue Number: 906
  • Publisher: Transportation Research Board
  • ISSN: 2572-3766

Subject/Index Terms

• TRT Terms: Bridge design; Bridges; Flexural strength; Load and resistance factor design; Material reinforcement; Specifications
• Identifier Terms: AASHTO LRFD Bridge Design Specifications
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 01713600
• Record Type: Publication
• ISBN: 9780309480574
• Report/Paper Numbers: Project 12-94
• Files: TRIS, TRB, ATRI
• Created Date: Aug 8 2019 2:19PM