Optimization of the Prestress Value in Binding of Reinforced Concrete Structures

AbstractThe value of prestress when manufacturing reinforced concrete structures is given in an arbitrary way within limits of maximum and minimum values that are recommended as normal values. While making calculations, it is necessary to ensure the implementation of a number of requirements that guarantee the operability of structures. Increasing prestress level leads to the upgrade of the cracking resistance and rigidity performance, and at the same time gives rise to the danger of destruction resulting from the concrete compression and destruction of bonds in a stress transfer zone from reinforcement to concrete at the manufacturing stage, as well as reduces the strength of a combined action of the bending moment and the transverse force near supporting structures. These problems become relevant during the production of hollow-core slabs in the process of formless molding as the installation of additional reinforcement in these slabs for increasing the bond strength near the supporting structures is impossible because of technological molding peculiarities. The need to optimize the value of prestess is conditioned by the occurrence of damages that appear at the manufacturing stage of intermediate hollow-core slabs of formless molding. The algorithm of optimization is introduced taking into account the ensuring of requirements of bond strength of reinforcement and concrete in the stress transfer zone, compression strength and cracking resistance