University Brixen
Project DescriptionThe new building at the University of Brixen (South Tyrol) should be adapted as a free standing structure to fit in with the medieval old town. For this reason the appearance of the structure is shaped through the use of only a few materials, mainly exposed concrete and glass. The building is constructed from prestressed and steel reinforced concrete and consists of 3 elevated (I am not sure if this is the correct translation for aufgeständerten. If it is then elevated upper stories is redundant) upper floors of a square ring and core building and despite a side length of about 75 meters the building is designed without any joints. TaskInitially there were difficulties with the production of exposed concrete components of the required quality and with general fluctuations in the strength of the concrete. We were therefore commissioned from the administration of the autonomous province of South Tyrol to develop a new concrete and quality management concept as well as to advise in terms of the forced tension and forced cracking problem in the layout of the reinforcement, which limits the width of cracks. ProcedureFor the production of the concrete sand and broken aggregates were available, which accounts for a very high water demand. For this reason, the cement content was significantly increased compared to the original concrete recipe, resulting in a greatly improved workability and robustness of the concrete. To obtain a sufficient and uniform concrete consistency, the mixing process is adapted in the stationary mixing location under utilization of the possibilities of the computer-controlled guidance and is executed in 3 steps: 1st step: dry premixing of cement and aggregate 2nd step: mixing with the addition of a portion of the water 3rd step: mixing with the addition of the remaining water and the plasticizer By improving the quality of detail points in the production, the quality of the exposed concrete components could be significantly increased. This concerned, amoung other things the design of framework joints, formwork ties, the minimization of the formation of shrinking, pores and blemishes, as well as the avoidance of rust flags and lime flags. Through the laboratory tests and mathematical evaluation of the actual properties of hardened concrete (E-modulus, coefficient of thermal expansion, shrinkage and plastic flow), the forced cut sizes and structure deformations could be realistically determined. The latter was crucial for the constructive design of the large-sized window elements.
|  ![Modell - Gesamtübersicht, Quelle: [1]](../../../media/3/3649.modell_gesamtuebersicht.png) Model - Overview  In the area of cutouts and closely reinforced components, large areas of flaws emerged as a result of the rapid setting of the concrete at high temperatures.  With the undertaken improvements in the concrete formulation, manufacture and install, as well as through consistent quality management, a very high quality concrete could be achieved. |
