Vol. 24, Number 3, 2018

Anatoliy Yugov, Anna Ihno, Tatiana Zhmykhova, Sergey Titkov
Full Factor Experiment for Optimization of Geometric Parameters of the Glass-Furnace Arches
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article considers the conduct of a full factorial experiment. The hypothesis of the reproducibility of the experiments was verified, which confirmed the fact that there was no need to conduct a repeat experiment. The emitting model is presented. By the method of least squares, the coefficients of the regression equation were found. The analysis of the model has shown the significance of not only linear effects but also of paired interactions of factors. The response surface is constructed, as well as the two-dimensional cross sections of the response surface.
Keywords: factor experiment, furnace arch, least squares method, model adequacy, linear interpolation.

Yevgen Gorokhov, Anton Tanasoglo, Alexandr Mushchanov
Estimation of Stability of Central Compressed Rods of Structural Coatings Taking into Account Structural Features of Knot Connections and Nonlinear Work of Material
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper presents the analysis of the stability of centrally compressed rods, taking into account the structural features of the node joints for which the models of volume finite element rods are made, the analysis of the stress-strain state of 6 standard sizes of tubular elements according to GOST 10704-91 «Electrically welded steel welded pipes» (in the range from 1144 to 15912 mm) in the software package of the LIRA-CAD family. The calculation is performed in a physically nonlinear setting in the elasto-plastic stage of the material. In the analysis of stability, the stability factor was analyzed from the results of nonlinear calculation (kf.s). Refined values of the critical force (Ncr, e.p.s) are presented. The obtained data were compared with the values of the critical force determined by DBN B.2.6-198:2014 «Steel structures» (Ncr, DBN). With the help of multiple linear regression, a generalized approximating relationship between significant factors influencing the refined value of the critical force (Ncr) and the value of the total deviation (ypr+ymax/l) is established in the Microsoft Excel program.
Keywords: structural coverage, centrally compressed rod, stability, finite element method, physical nonlinearity, elastic-plastic material work.

Vadim Gubanov, Yana Zikii, Alina Pchelenko
Studies of Efficiency of Tie Rod Usage for Masonry Wall Strengthening
Donbas National Academy of Civil Engineering and Architecture
Abstract. In the paper the influence of nontensional horizontal steel tie rods installation in a building perimeter on vertical and horizontal deformations of bearing walls of stone buildings is considered. Buildings of large blocks and bricks, loaded with constant and temporary loads were taken as initial data. By the way of the special effects it has been given ground vertical shifts which are accorded to mould radii of displacement through underworking. The stress-strain state of buildings was determined on the basis of numerical calculations using 3D models. The dependence of wall deformations from an area of ties to be installed at each floor level was obtained. For generalization the values of deformations were received as a function of an uneven relative settlement. It has been determined that the horizontal deformations is reducing up to 1,5…2,5 times (efficiency factor of 0,67…0,4) while a relative settlement does not exceed of 0,004. The research has demonstrated a usage of untensioned tie rods to be not effective in all for masonry wall strengthening.
Keywords: masonry buildings, undermining, uneven settlement, numerical studies, strengthening, untensioned tie rods.

Volodymyr Mushchanov, Vladimir Shpinkov
Updated Assessment of Joint Work of Thin-Sheet Membrane Coating with a Reinforcing Element
Donbas National Academy of Civil Engineering and Architecture
Abstract. In the article it has been considered the technique of determination of effective flange width of I-beam used in conjunction with sheet membrane coating, including on the basis of the computation of the reduction coefficients. The applicability to the solution of this problem of the approaches described in the works of P. F. Papkovich and the norms of the Eurocode (part 1.5) has been analyzed, where the joint work of the thin-sheet membrane coating and the reinforcing element under the action of the distributed load has been considered as the object of research. The results obtained using analytical methods of the solution are supplemented by finite element analysis of the inclusion of a thin-sheet membrane plate in the joint work with the I-beam element for transverse bending, the simulation of which was carried out using shell elements in a geometrically nonlinear formulation. Obtained results allow us on the basis of refined approaches to estimate the size of the membrane plate area involved in the joint work on the transverse bending with a reinforcing element.
Keywords: reduction coefficient, membrane plate, reinforcing elements, effective width.