JOINTS - PROBLEMS RELATED TO BAD WORKMANSHIP OR TO THE INAPPROPRIATE CONSTRUCTION TECHNIQUES IN MASONRY

摘要

There are two aspects of the joints that we are relating to in this article. The first one, which can be assign to the bad workmanship, is the experimentally supported evaluation of the influence of the large proportion of the overgrained sand particles on the mechanical properties of the traditional brick masonry. The tests of the masonry which were carried out through compressive test of masonry specimens of the size of the wallette as well as through bond tests showed the significant influence of sand gradation both on the compressive strength of the masonry and on the bond strength of the brick-mortar junction. The second aspect, which according to some codes can be attributed either to the bad workmanship or to the inappropriate construction technique, is execution of the head joints in contemporary block masonry and its possible impact on the overall resistance of the masonry due to the earthquake load. Although the problems related to the execution of the head joints and its influence on the shear strength of the masonry is partly incorporated in the new EC 6 (EUROCODE 6, 1997), there is still lack of knowledge of the overall resistance of masonry under the earthquake loading. According to the EC 8 (EUROCODE 8, 1994) except in zones of low seismicity (a_g≤0.05 g.) perpend (head) joints should be fully filled with mortar. This clause, as well as some recent research results on that topic, can limit the applicability of many modern types of newly developed clay blocks in earthquake prone areas.