No 5 (2017)

Graphical computer modeling is a real possibility of solving problems on the formation of surfaces by a kinematic method. It is due to the presence of automated design systems, such as MathCad, Mathematika, AutoCad, etc. The advantage of the AutoCad system is the presence of the built-in language of functional AutoLisp. Having a wide range of mathematical functions and functions for drawing graphic objects, the AutoLisp language allows you to write a program for drawing shells of any complexity, in a particular case - shells of the same ramp on the elliptical plane, the surface of the involute helicoid, and then transferring the results to the AutoCAD environment. Playing objects in slow motion makes it possible to compose mini-films about the formation of surfaces. The image of graphical constructions in three-dimensional space using the AutoCAD color palette enhances the expressiveness of the image of surfaces and their elements. The aim of the study is the possibility of modeling the surface of the equal slope ramp on an elliptical plane, carried out by its gradual drawing in a slow dynamic mode with the creation of a mini-film that allows the surface to be displayed on the monitor screen

The paper describes a method for determining coefficients of load and bending-stress distribution along a rigidly fixed thick plate which is in edge contact with the other part when no load is applied. The method is based on the solution of integral Volterra equation which binds angle between contacting elements and components of strain.

The article describes methods for reliability analysis of reinforced concrete beams with shear cracks by the criterion of the rebar strength. Reliability analysis is conducted on the basis of the provisions of reliability theory and fuzzy set theory to account for the limited statistical information on con- trolled parameters. We considered two design cases with different numbers of fuzzy variables in the design mathematical models of a limit state. Numerical examples of reliability analysis are given. The proposed methods may in some cases contribute to accidents prevention in reinforced concrete beams, and in other cases get the economic effect from the rejection of strengthening or replacement of beams, even when the crack width exceeds the ultimate value

He geometry of the flat statically determinate truss with two fixed hinge supports is specified by the lengths of the rods, the number of panels in supporting parts and the number of panels in the bolt. By induction on these parameters the General formulas for the deflection of the trusses under the action of concentrated and distributed load are obtained. Symbol conversions are performed in the system of computer mathematics Maple. The asymptotic properties of solutions are found. Formulas for reactions of supports and efforts in the most compressed and stretched the rods of the truss are found

The article deals with overall sustainability of stiffening diaphragm of support structures in engi- neering construction in the context of structural elements collaboration as a system «high rise construc- tion- foundation (base)- ground base». Calculations were made in the program complex LIRA-CAD. It was found out that the general stability of the bearing systems, which are paired diaphragms of rigidity in the form of support structures of a large-span structure with a highly located center of gravity, depends on their location on the base plate.

In the article, the experimental results of deformation, cracking and failure of a reinforced concrete frame when loaded over the designed specifications, or when overloaded by a sudden failure of a pillar are presented. The results of displacements and cracking caused by the load at the main support points, for bending and twisting, give an opportunity to determine the survivability parameters and the dynamic overload values for the construction elements. The results can also provide information about the survivability of a building after being overloaded.