Tube-jack testing: regular masonry wall testing

Abstract

Tube-jack testing is an enhanced non-destructive test method being developed at the University of Minho as an enhanced version of the traditional flat-jack test method. The tube-jack system consists of several tube-jacks, instead of flat-jacks, roughly aligned in holes drilled into the mortar joints, of the masonry to be tested, forming an equivalent flat-jack. The tube-jack system can be used similarly to the flat-jack system to test the mechanical properties of historical masonry during inspection and diagnosis of a masonry structure. In this paper the testing of the complete tube-jack system in a regular masonry wall is pre-sented. Several single tube-jack tests were performed in horizontal joints in a regular mason-ry wall, made of granite and cement-lime mortar, built in the laboratory for this purpose. The tests were studied to determine if they could accurately estimate the stress level in the masonry. A double tube-jack test was also performed to determine if this method could be an alternative to the double flat-jack test. Finally, these tube-jack tests were compared to single and double flat-jack tests performed next to the tube-jack tests in the same masonry wall. The results and conclusions of each of these tests are discussed and possible future improve-ments to the tube-jack system are presented.