Velipoja is considered a seismic region in Albania. In the past years, due to the mountainous landscape and presence of several rivers, in the region of Velipoja have been built different bridges and their maintenance has been insignificant compared to their needs. The recent earthquakes, environmental effects and vehicle loads have damaged the bridges and prompting the need for repairing and strengthening their structure. Replacement with new structures raises financial and technical problems. Rehabilitation of existing bridge is one of the most important actual problems. The main purpose of this paper is to examine the existing structure and to develop design strategies to make the structure as insensitive as possible to the unknown characteristic of the input seismic excitation. The most common technique implemented has been steel jacketing, concrete jackets or composite materials jackets 3 . Fiber-reinforced (FRP) composite materials have been used for external strengthening of concrete structural components 4 . This paper presents some retrofit practices and details used in the bridges of Velipoja region.

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SUMMARYThe paper addresses the problems of evaluation of strength, deformability, and energy dissipation capacity of unreinforced brick masonry walls, within the context of seismic assessment of existing buildings. Possible approaches to simplified strength evaluation are discussed on the basis of experimental and numerical data, and formulae for assessment are presented. The role of the shear ratio in the shear failure mechanisms is put in evidence and shear strength formulae are proposed accordingly. The most significative parameters regarding deformability under cyclic loading are highlighted and energy dissipation due to hysteretic behaviour is quantified for possible use in dynamic models. Experimental results show how ultimate drift seems to be a parameter with high regularity for walls failing in shear. Based on such result, a possible approach for seismic assessment is outlined.

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