CALCULATION OF CONTINUOUS REINFORCED CONCRETE BEAMS WITH ADDITIONAL DISPERSED REINFORCING BY STEEL FIBERS, TAKING INO ACCOUNT THE REDISTRIBUTION OF FORCES

Abstract

A special place in the study and improvement of the work and calculation of reinforced concrete structures is occupied by statically indeterminate structures, in particular inseparable multi-span beams.

A characteristic feature of the continuous beams is the redistribution of forces in the sections, which is often characterized even at the operational levels of the load. As the load increases, the reinforced concrete structures develop significant inelastic deformations caused by the occurrence and development of cracks in the stretched zone, violation of the adhesion of reinforcement to concrete, the creep of concrete.

The problem of the described redistribution of forces in statically indeterminate reinforced concrete structures is currently widely disclosed, considerable laboratory and practical experience has been accumulated. However, this applies to structures with classical reinforcement. Today, the use of dispersed reinforcement, in particular steel fiber concrete, as well as combined reinforcement, is becoming more and more relevant. In order to study the effect of such reinforcement on the redistribution of forces in combined-reinforced statically indeterminate structures and their stress-strain state, a number of experimental studies of two-span continuous reinforced concrete beams with additional dispersed reinforcement were performed. The research results showed significant differences in the operation of combined-reinforced beams under single loads, compared with classical structures. Therefore, the question arose about improving the method of calculating beams of this type.

The article presents the disadvantages of using the existing method in the calculation of continuous beams with combined reinforcement. An improved method for determining the magnitude of bending moments in inseparable combined-reinforced beams, taking into account the redistribution of forces with good convergence, based on experimental studies, is also proposed. A statistical comparison of the obtained theoretical results with experimental data is performed.