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Eurocode 8 allows that any country can use its own shape of the elastic response spectrum after it defines it in the National Annex. Having in mind that such country-specific spectra are to be derived through analysis of the strong motion data recorded in the considered seismo-tectonic region, in this Paper we discuss the existing and a set of new empirical equations for scaling pseudo-acceleration spectra in Serbia and the whole region of north-western Balkans. We then compare the presented spectra to those proposed by Eurocode 8. Results show that the indiscriminate use of the strong motion data from different seismo-tectonic regions, improper classification of the local soil conditions, and neglect of the effects of deep geology, may all lead to unreliable scaling equations and to extremely biased ground motion estimates. Moreover, only two spectral shapes that are defined for wide magnitude ranges and scaled by a single PGA value, are not able to adequately represent all important features of real strong ground motion, and instead of using such normalized spectra one should rather employ the direct scaling of spectral amplitudes that is based on the analysis of regionally gathered and processed strong motion data. [Projekat Ministarstva nauke Republike Srbije, br. 36043

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Application of modern seismic design codes in everyday practice imposes a need for the seismic retrofit of existing structures, which represents a challenging task when it comes to old masonry buildings. Many of such buildings were built long before design codes, not just seismic ones, and in many cases their structural performances do not conform with the current design criteria. Seismic response of existing masonry buildings, especially public ones, has a strong impact on the society, and therefore deserves a proper attention. There is a constant need for an improvement of the seismic capacity of old masonry building structures. One of such examples is presented in this paper, which deals with the seismic retrofit of an existing grammar school masonry building in Novi Sad, Serbia. The building was built about eighty years ago, before any design codes. It consists of a basement, ground floor and two upper floors. Structural walls were constructed by using solid bricks without reinforcement, and ribbed floor slabs were made out of reinforced concrete. During the on-site inspections no vertical confining elements were observed, and only some horizontal confining elements were found at floor levels. What makes the retrofit project special is the fact that a new storey is planned to be built upon the existing top storey in order to expand the school's capacity, which has further complicated the analysis and design. This paper presents the most important properties of the considered masonry building, the results of nonlinear static (pushover) analyses performed on a spatial mathematical model of the structure with the additional storey, and the applied retrofit solutions used to achieve the necessary seismic capacity with the respect to the provisions of Eurocode 8.

If experimental studies are difficult to conduct, the validation of results obtained using numerical procedures can be achieved through comparative analyses performed by different numerical model codes. In this paper, analysis of a simply supported steel beam subjected to fire is performed using open source software OpenSEES and a commercial software ANSYS Workbench. Both material and geometrical nonlinearities are taken into account. Calculation methodology is adopted according to Eurocode standards EN 1991-1-2 and EN 1993-1-2. Results, in terms of the midpoint displacements in time, are compared and discussed.