THE SHEAR CAPACITY OF THE REINFORCED CONCRETE BRIDGE BEAMS

Abstract

The article considers the solution of the scientific and practical problem of specifying the shear capacity of reinforced concrete bridge beams. Solution of the problem is based on example of the reconstruction of the bridge across the river Southern Buh in Chernovol street in Vinnytsia. These beams with a span of 7.5 m rest on the upper structures of the main spans of the bridge with a length of 45 m. Calculations according to current standards showed that the shear capacity of the beams is insufficient and they need to be strengthened. Additional research by the field test method made it possible to specify the actual level of stresses in the cross-sections of bridge beams and the actual nature of cracking along length of beams. Based on these data, repeated calculations were made to check the shear capacity of the bridge beams. These calculations made it possible to identify additional reserves of the bearing capacity of the inclined cross-sections of the beams and to abandon the need for strengthening. The identified reserves of the shear capacity are partially due to a cautious approach when determining and taking into account the initial data for the calculations of structures that have been operated for a long time without proper technical support. In addition, modern standards for the design of reinforced concrete structures in terms of ensuring the shear capacity do not allow taking into account the peculiarities of the operation of reinforced structures, are based on simplified models of the operation of reinforced concrete beams at the supporting sections and therefore require further development and improvement.