Položaj vertikalnih konstruktivnih elemenata ima dominantan uticaj na ponašanje konstrukcije pri seizmičkom dejstvu. Neadekvatan položaj krutih elemenata dovodi do neželjenih osobina konstrukcije kao što je pojava torzionih oscilacija u I osnovnom tonu ili pojava velike ekscentričnosti centra krutosti u odnosu na centar masa. U radu je analiziran uticaj ekscentrično postavljenog liftnog jezgra na dinamičke karakteristike armiranobetonske stambene zgrade sa pravougaonom osnovom spratnosti P+6. Dodavanje AB zidova za otvor za lift za posledicu ima pojavu torzije u I i III tonu oscilovanja i značajnu promenu ekscentričnosti centra krutosti i centra masa, što sa konstruktivne tačke gledišta nije dopustivo. Da bi se obezbedio dobar prijem seizmičkih sila i otpornost opisane konstrukcije na seizmička dejstva predloženo je dodavanje AB platna na odgovarajućim mestima. Na osnovu dobijenih rezultata može se zaključiti da se dodavanjem AB zidova bitno popravila seizmička otpornost konstrukcije. Seizmički proračun urađen je metodom ekvivalentnog statičkog opterećenja i primenom spektralne analize u skladu sa važećim domaćim propisima. U radu je pokazano da se u slučaju konstrukcije sa neadekvatnim rasporedom krutih vertikalnih elemenata sračunava pomeranje vrha objekta za oko 21% manje primenom metode ekvivalentnog statičkog opterećenja u odnosu na spektralnu analizu, na osnovu čega se izvodi zaključak da primena metode ekvivalentnog statičkog opterećenja ne daje uvek dovoljno tačne rezultate.

This paper presents the dynamic analysis of prestressed reinforced concrete road bridge "Goce Delchev" over the river Vardar in Skopje from the aspect of dynamic stability. The bridge span is 88,00m with overhangs2x29,20m, founded on wells (caissons) whereby the height of the upper edge of the well to the upper edge of the bridge is 14,37m. The longitudinal slope of the bridge is in the gentle slope of 0.57%. Experimental testing on theforced vibrations of the bridge was performed, and then a mathematical model was formed and dynamic analysiswas made. This was necessary, because the superstructure of the bridge is complex cross-section and behaves differently in the longitudinal and transverse direction and the effect of different soil-structure interaction. From all of the above it can be seen that the obtained corresponding influences mutually greatly match.

The paper gives a theoretical basis and terms for calculation of static and dynamic impact of girders with semi-rigid connections of members in joints. In the existing literature calculation of line systems in which the connections of members in joints are absolutely rigid or ideally pinned has been elaborated in detail. In real structures in general, and particularly in the precast ones, connections may be partially rigid, which can have a significant impact on the change of stresses and strains in the construction. In the world there are several procedures with different approaches to the calculation of structures with semi-rigid connections, but it was proven that all of them lead to the same results. All of these approaches give experimental analysis of the results in addition to theoretical one