MEASUREMENT AND CONTROL OF THE REACTION FORCES OF A REINFORCED CONCRETE BOX GIRDER BRIDGE CONSTRUCTED BY INCREMENTAL LAUNCHING

Abstract

The measurement and control of the reaction forces of a three-span 114,5 meter long reinforced concrete box girder bridge built by incremental launching is reviewed. Using the complex lifting and measuring system it was possible to determine the effective dead load of the bridge during the lifting at eight points. By means of the observed alteration of the reactions suitable to the different values and combinations of the vertical displacements it was possible to calculate the proper vertical position of the bearings answering the designed reaction forces. The 22 % difference between the reaction forces of the designed and launched structure justified the necessity of checking. The decsease of the deviations under a 1 % limit proved the suitbility of the measuring system and the method applied.