TIES IN UNREINFORCED MASONRY STRUCTURES: CASE STUDY IN KRK

The recent earthquakes in Croatia have reminded us that heritage masonry buildings are highly vulnerable to seismic actions. This paper will focus on the out-of-plane failure mechanisms, which result from scarce wall-to-wall and wall-to-floor connections. To prevent these mechanisms, masonry buildings should have adequate structural integrity, i.e. they should behave like a box. This paper examines the use of ties in an 18th century stone masonry building in Krk, Croatia. Over the years, the three-story building has undergone various reconstructions. The floor structures are made of timber beams and boards, as is common in this region. The beneficial connecting details include: i) the connection between the timber beams and the masonry walls made via anchoring iron ties, placed at every third beam in the floor; ii) the attic walls connected via iron ties at corners to prevent their separation; iii) diagonal iron ties used to connect the attic walls and the floor beams and iv) timber ring beams inserted into the walls to act as a horizontal tie. Although the use of timber ring beams as ties is quite common in adobe masonry, it is not so common in stone masonry. The authors have not so far detected any timber ring beams embedded into masonry in this region. The mechanical properties of wrought iron ties have also been investigated.