Calculation of bearing capacity of normal cross-sections of combined-reinforced sfrc bending elements

Abstract

In recent years, the scope of application of reinforced concrete and combined-reinforced structures in load-bearing structures is expanding. Studies by many authors indicate the significant advantages of reinforced concrete and combined-reinforced bending elements over the classic reinforced concrete. Current state regulations do not take into account all the properties of reinforced concrete, and therefore the load-bearing capacity of structures can in many cases be underestimated. Therefore, it is advisable to take into account, when calculating, all the properties of this material.

The current state standards for the calculation and design of reinforced concrete structures are based on the fact that reinforced concrete is considered as one of the types of disperse-reinforced material. However, with this approach, many factors are taken into account, the value of which, in real conditions, can be in a wide range of values, so they are taken into account with a margin.

The article proposes a simplified force method for calculating the bearing capacity of combined-reinforced reinforced concrete bending elements. Simplified diagrams of deformation of reinforced concrete under compression and tensile obtained on the basis of experimental tests are taken into account. The tensile diagram is proposed to be three-line. To evaluate the effectiveness of the method and study a number of other characteristics, two series of experimental studies of inseparable combined – reinforced concrete beams were performed. Research methods and the nature of the beams in the test process, described in [8-10]. For comparison with the obtained experimental data, the article presents the calculation of experimental beams, performed according to state standards and a simplified force method.

The results show that when determining the load-bearing capacity of the section, the results determined by a simplified force model show the best agreement with the experimental ones. It is obvious that taking into account the full operation of reinforced concrete in compression and tension, increases the accuracy of the calculation. The average error is 3… 5%.