In this paper the structural analysis and design of reinforced concrete building located in Rijeka are carried out. The listed building is of business purposes and consists of two basement floors, ground floor, six storeys above and flat roof with overall dimensions of 18,00 x 36,00 m. The building consists of reinforced concrete slabs, supported by reinforced concrete beams, which together with the columns create a framework system. Bracing elements of the structure consists of reinforce concrete core walls and basement walls. Structural analysis for permanent and seismic design situations was calculated using the Staad.PRO V8i SS6. The influence containing backstay diaphragms during the seismic design situations were analyzed. Structural design was carried out for the tallest basement floor diaphragm, for permanent and seismic design situations. After defining the needed reinforcement for permanent design situation, the punching control was also made. By analyzing the results in tallest basement floor diaphragm, two strut-and-tie models were made for determination of seismic forces, based on which an additional reinforcement was calculated. Furthermore, structural design was carried out for core walls in critical area, below and above the tallest basement floor diaphragm, for permanent and seismic design situations. Structural analysis were made in accordance to EN 1992-1-1 i EN 1998-1.