ABSTRACT
ABSTRACT: In the paper the practical possibility of strengthening of reinforced concrete roof girder with unbonded tendons is presented. The mention above girder, double T in cross section, has been cracked due to the external dead loading. During control of existing technical state it was located about 140 normal cracks in the bottom flange coming to the web as well as the diagonal cracks. The maximal width of normal cracks was equal to the 0.4 mm, and the diagonal cracks was equal to 0.6 mm. The system of strengthening is discussed. The influence of presstresing to structure deformation has been investigated.The readings of concrete strains at upper, bottom flanges and web girder have been taken with mechanical gauges DEMEC type. The results obtained from investigations were compared to the ones from FEM numerical analysis. The final findings dealing with the applied technology of strengthening has been also discussed.
