Unorthodox structural solutions dor the "Gate of Poznan" building as a way to accomplish an audacious architectural idea

The "Gate of Poznan" is one of the most unorthodox buildings accomplished in Poland in the last years. It was designed on the basis of the winning project of the international architectural competition. Our team of structural engineers faced and solved many unusual problems mostly caused by a cantilever form of the building with a suspended pedestrian bridge. The main sources of problems were: general structural system consisting of highly strained concrete cantilever walls with openings, irregular loads on the foundations with some areas of an uplift, vast use of an architectural concrete in structural elements both inside and outside of the building. Special system of slabs with internal lightening cavities was used in order to reduce weight of the cantilever part and to cover a span up to 15 m. External walls were designed as the sandwich structures made of architectural concrete with external layers with no expansion joints. The pedestrian bridge with a span of 62,4 m was analyzed paying special attention to dynamics and vibration