Lightweight Concrete Modification Factor for Shear Friction

This project is aimed at studying the influence of aggregate type on direct shear transfer across an interface of concretes cast at different times. The shear friction design concept is applicable in conditions where direct shear must be transferred across a structural concrete plane or interface, such as an existing crack or an interface between dissimilar materials or concretes cast at different times. Shear friction provisions are commonly used in the design of precast-prestressed concrete elements and connections in building and/or bridge structures including corbels, dapped double tees, beam bearings, and diaphragms. These types of connections are critical because there is little or no redundancy. Data used to develop shear friction provisions in both the ACI 318 Code and the PCI Design Handbook are predominantly from experiments with specimens constructed of normal weight concrete (NWC). Only a limited number of studies have been performed on lightweight concrete (LWC), and particularly for conditions with concrete surfaces cast at different times. This condition may exist, however, due to precast plant practices and the increasing use of self-consolidating concrete (SCC), and where projecting elements might be cast after the underlying concrete has partially hardened. Alternatively, projecting elements might be cast in advance and inserted into the fresh concrete when the main member is cast, resulting in a similar condition. It should also be noted that the influence of SCC on the interface shear has not been thoroughly studied. In summary, lack of LWC test data and clear and consistent design provisions underscore the need for a systematic approach to isolate and examine the influence of factor λ on the interface friction so that it can be applied clearly and confidently in shear friction design.


  • English


  • Status: Completed
  • Funding: $30000.00
  • Contract Numbers:



  • Sponsor Organizations:

    Precast/Prestressed Concrete Institute

    200 W Adams Street, #2100
    Chicago, IL  United States  60606-6938
  • Performing Organizations:

    Center for Infrastructure Engineering Studies

    Missouri University of Science and Technology
    Rolla, MO  United States  65409
  • Principal Investigators:

    Sneed, Lesley

  • Start Date: 20110815
  • Expected Completion Date: 0
  • Actual Completion Date: 20120814
  • Source Data: RiP Project 28361

Subject/Index Terms

Filing Info

  • Accession Number: 01503737
  • Record Type: Research project
  • Source Agency: Center for Infrastructure Engineering Studies
  • Contract Numbers: DTRT06-G-0014, 00034650
  • Files: UTC, RIP
  • Created Date: Jan 16 2014 1:00AM