Development of the Methodology for Monitoring the Technical State of Bridge Structures and Establishment of Safe Operating Period

A methodology for determining the technical state of reinforced concrete bridge structures was developed. It is based on establishing the depth and location of the largest deflection using a laser projection system, as well as an approach to finding the stress-strain state (SSS) along the height of the beam. An energy approach, which foresees the energy of elastic-plastic deformation calculation of concrete and reinforcement was used for this. The specific fracture energy as an invariant characteristic of concrete strength under tension, compression, and also tension of reinforcement were established experimentally. The true diagrams of deformation and fracture of concrete samples taken from the structure were plotted. The results of experimental studies of SSS during the bending of a reinforced concrete beam agree well with those calculated by the finite element method.