Implementation of calculations of normal sections of reinforced concrete structures in software packages

Introduction. In previous publications, the authors examined the features of calculating the strength of normal sections of reinforced concrete structures associated with the possibility of using two approaches – the nonlinear deformation model (NDM) and the method of limiting forces (MLF). Using specific examples, the results obtained with both approaches are compared. Cases of significant discrepancies in the consumption of selected reinforcement have been identified, trends have been explained, and the physical essence of the phenomenon has been analyzed. Calculations were performed according to the OM SNiP Reinforced Concrete program.

Aim. To analyze the implementation of features when using various computer programs for calculations of reinforced concrete structures, identify differences in results, establish their physical cause, evaluate economic aspects and problems, and make the necessary recommendations.

Materials and methods. The studies were performed for three types of structures. The first type included four sections of elements under two stress states: off-center compression (rectangular and annular) and oblique offcenter compression (rectangular and I-beam). The second type of structures included columns and pylons of a projected and constructed reinforced concrete building. The third type was an illustrative example – the T-section of the bent element at different operating moments and percentages of reinforcement. Calculations of the first type of structures were carried out by the authors by the OM SNiP Reinforced Concrete program, as well as the program developers of the Ing+, Arbat, Lira-SAPR, Lira 10, STARK ES programs. The calculation of structures of the second type was carried out by the authors by the OM SNiP Reinforced Concrete program and the designers by the Lira-SAPR 2022 program. The test example was calculated by the authors according to the OM SNiP Reinforced Concrete program.

Results. When calculating according to the NDM, a significant unjustified overspending of the required reinforcement was revealed compared to the calculation according to the MLF. In an illustrative example, the overspend is 220 %.

Conclusions. The general state of calculations of reinforced concrete structures should be recognized as requiring adjustments. To obtain a multibillion-dollar economic effect, it is proposed to provide in SP 63.13330.2018 two equal approaches to the calculation of normal sections of reinforced concrete structures - NDM and MLF. It is advisable to develop a document with a set of reference examples that allows you to get the same results for different programs with the same source data.

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