Author(s)

F. V. Karantoni

Abstract

The strengthening measures of an unusual masonry building of high seismic vulnerability are presented and assessment of their effectiveness is performed. The building is highly asymmetric and it is located in a zone of seismicity II, according to Greek Seismic Code. In addition, two adjacent walls have openings along 71% of their length. The building is scheduled and the authorities responsible for the preservation did not allow interventions that may alter its faces. Herein, the seismic response of the structure as well as the effectiveness of the finally adopted measures is presented. The effectiveness is assessed by comparing the overstressed areas of the original building with those of the strengthened one. The measures proposed are the replacement of flexible floors by stiff composite slabs, the construction of a reinforced concrete tie belt at the top of all structural walls, grouting of cement grout, repointing the masonry and the construction of a double shotcrete jacket. Key words: masonry buildings, damage, vulnerability, strengthening. 1 Introduction A historic or a scheduled building often remains undamaged regardless of the seismicity of the area, the empirical way of construction, and the lack of design. Sometimes, observing an old building makes us think that nowadays it would be constructed with a quite different engineering design. This paper is involved with such a building. The unusual structure under consideration is a building highly asymmetric in plane and in elevation, with few structural walls. The relatively high structural walls (up to 11.2 m) of the north and west sides have many openings of approximately 71% of the length of the walls, the upper storey has an area of about one half of the lower storey, and the building has no rigid diaphragms. It has floors and a roof of timber joists.

Keywords

masonry buildings, damage, vulnerability, strengthening.