MODERN APPLICATION OF THE GRAPH-ANALYTICAL METHOD OF CALCULATION OF STEEL TRUSS

Purpose. The main purpose of the publication is to quantify the accuracy and probability of applying the graph-analytical method of determining the distribution of forces in the elements of a steel rafter truss based on the use of the modern AutoCAD complex. Methodology. To achieve the formulated purpose, three projects of food and non-food stores located in the cities of Zbarazh, Novohrad-Volynskyi and Kryvyi Rih were considered. The covering of stores in all three cases is made on the basis of flat steel trusses, which were accepted as the object of research. The implementation of the graph-analytical method of constructing the Maxwell-Cremona diagram was carried out on the basis of the AutoCAD complex. The loads were taken in accordance with the actual operating conditions according to the current DBN standard B.1.2-2:2006. The assessment of the accuracy of the Maxwell-Cremona diagram construction was carried out on the basis of a comparison with the numerical method of construction mechanics – the method of finite elements based on the SCAD design and calculation complex of domestic development. Findings. A quantitative comparison of the values and character of the distribution of internal forces in the elements of steel trusses of the coating showed that, on average, the divergence between the graph-analytical method and the finite element method does not exceed 3%. Also, the use of the graph-analytical method allows obtaining the full distribution of forces in truss structures, without requiring the skills of using specialized packages of numerical analysis application programs, such as SCAD or Lira. Originality. In the course of the conducted analysis, the degree of theoretical coincidence of the results of graph-analytical and numerical approaches to the assessment of the distribution of internal forces in the elements of the steel trusses of the coating was determined. Practical value. The obtained results of the assessment of the probability of using the graph-analytical method open the prospects of its widespread use as an alternative to analytical or numerical methods of construction mechanics for modern complicated «field» conditions, when there is a need to provide a quick assessment of the bearing estimation of a damaged or destroyed building structure.