ABSTRACT
Traditional masonry chimney systems are regarded as highly vulnerable due to seismic events. The general perception is that they will fail even in the case of moderate earthquake. Despite severe damages of masonry units, ceramic flue liners stayed undamaged until the end of testing. Seismic behaviour of chimneys largely depends on so-called coupling effect between primary structure and chimney as secondary element. The most of contemporary masonry chimney systems do not fulfil some of the requirements and it exist reasonable fear amongst chimney producers that structural requirements as stated in informative annex of EN 1998-6 may jeopardize their position on the markets. Vertical cracks along masonry units were mainly due to the low tensile strength of units and very stiff behaviour of grout and steel bars in relation to masonry units. Stiffness and strength properties of grout and reinforcement should be adjusted with mechanical properties of masonry units; otherwise reinforcement will provoke failure of masonry unit.
