Research Activities: 2012

Strength of Unbonded Post-Tensioned Walls
 
 Status Complete                            View Final Report: PDF
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Sequential Number R349
 
Identification Number 00042597
   
Matching Research Agency

Midwest Block and Missouri University of Science & Technology – Civil Engineering
 
Principal Investigator

Mohamed ElGawady
Associate Professor
Missouri University of Science and Technology
211 Civil Engineering
Rolla, MO 65409
(573) 341-6947
elgawadym@mst.edu
 
Student Involvement

2 graduate students
 
Project Objective The study objectives are:
  • Determine the effects of tendon spacing on strength of post-tensioned walls
  • Determine the effects of shear reinforcement on the strength of post-tensioned walls
  • Verify the current MSJC (2011) shear and flexural strength equation
 
Project Abstract Post-tensioned masonry walls (PT-MWs) will be an ideal candidate for accelerating the construction of sound barriers in highways. PT-MWs have been in use for a while; however, there has been no rigorous single-study
in the United States about in-plane strength of PT-MWs built out of concrete masonry units. This project will investigate the in-plane behavior of six full-scale unbonded post-tensioned walls. All the walls will have the
same total post-tensioning force and identical dimensions of 104 in. long, 96 in. high, and 8 in. wide. Spacing between tendons ranging from 32 in. to 96 in. will be investigated. The walls will be subjected to in-plane shear
loads of increasing amplitude. Both flexural strength and shear strength will be evaluated and compared to the strengths given by MSJC (2011). The stresses in the tendons will be measured using strain gauges and
compared to different formulae.
 

Relationship to other Research/Projects

The PI just published a journal manuscript in the ASCE Structural Engineering showing that current design procedure of posttensioned
masonry walls resulted in inconsistent results.
   

Transportation-Related Keywords

 Shear strength, sound walls
   

Technology Transfer Activities

Peer-reviewed journal and conference papers will be published
   

Project Deliverables

 A report and presentation at the NUTC annual meeting
   

Anticipated Benefits

Masonry walls are used as a sound barriers in several state DOTs. An emerging type for accelerating the construction of masonry walls are the use of post-tensioned masonry walls.
While several tests have been carried out to investigate the strength of post-tensioned masonry walls in New Zealand, there have been no tests carried out in the US. Hence, this research will help the engineering community to investigate the accuracy of current MSJC standard. Also,
using post-tensioned masonry walls will allow the development of precast masonry walls which will help in accelerating the construction, increase quality control, and use material more efficiently.

Milestones
Project Start Date: 1/05/2013
Project End Date:

05/15/2014