Mathematical model for evaluating temperature stresses in concrete bridge beams strengthened with external reinforcement adhered with methyl methacrylate compositions

The object of the study is concrete bridge beams strengthened with external reinforcement adhered with methyl methacrylate compositions. A method for strengthening defective concrete bridge beams using methyl methacrylate based compositions is presented. A mathematical model has been improved for evaluating the temperature field and temperature stresses in a multilayer structure formed during the strengthening of defective beams with external reinforcement adhered with methyl methacrylate compositions. The distribution of temperatures and stresses in a strengthened concrete bridge beam under the influence of climatic temperature changes in the environment was investigated. A temperature gradient was found to occur at the interfaces between structural layers. At the same time, thermal stresses are also distributed unevenly in the vertical direction of the strengthened bridge beam: a discontinuity in thermal stresses occurs at the boundaries of contact between the structural layers. It has been established that under positive ambient temperatures, the magnitude of the temperature stress discontinuity in the vicinity of the contact plane between the upper edge of the polymer concrete layer and the lower edge of the reinforced concrete beam was 14.64 MPa, under the influence of negative temperatures it was 9.09 MPa, and under the influence of positive and negative temperatures on different surfaces of the beam, the maximum value of the discontinuity in thermal stresses was 1.74 MPa.