Strength of Unbonded Post-Tensioned Walls

Post-tensioned masonry wall (PT-MW) is an ideal candidate for accelerating the construction of sound barriers in highways. PT-MWs have been in use for a while in buildings; however, there has been no rigorous single-study in the U.S. about in-plane strength of PT-MWs built out of concrete masonry units. This resulted in some contradictions between International Building Code (IBC 2010) and Masonry Standard Joint Committee (MSJC 2011). MSJC (2011) defines three types of PT-MWs: ordinary plain, intermediate, and special. However, the IBC (2010) combines the different types of PT-MWs into one type similar to that of unreinforced masonry (URM) walls. This represents a significant contradiction. Specially designed PT-MW would be designed according to MSJC (2011) for a seismic lateral force equal to one-third the required seismic force according to IBC (2010). Moreover, according to MSJC (2011), both intermediate and special walls have identical prescriptive bonded mild steel reinforcement and post-tensioning bars which is similar to that of specially reinforced masonry walls while the IBC (2010) does not have similar recommendations. Finally, ordinary post-tensioned walls do not have maximum spacing between tendons in both MSJC and IBC. Hence, there is a crucial gap in the current knowledge which requires an immediate investigation. This project investigates the in-plane behavior of full-scale unbonded post-tensioned walls. All walls have the same total post-tensioning force and identical dimensions of 104 in. long, 96 in. high, and 8 in. wide. Spacings between tendons ranging from 24 in. to 96 in. were investigated. The walls were subjected to in-plane shear loads of increasing amplitude. Both flexural strength and shear strength were evaluated and compared to the strengths given by MSJC (2011).

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 51p

Subject/Index Terms

Filing Info

  • Accession Number: 01537429
  • Record Type: Publication
  • Report/Paper Numbers: NUTC R349, Project #00042597
  • Contract Numbers: DTRT06-G-0014 (Grant)
  • Files: UTC, TRIS, RITA, ATRI, USDOT
  • Created Date: Aug 29 2014 3:36PM