Ключевые слова: здания и сооружения, железо-бетонные конструкции, неразрушающие испытания, оценка огнестойкости, методика расчета, ресурсо-энергосбережение.

Abstract. The research introduces a methodology of establishing indicators of fire safety of a building in relation to a guaranteed duration of steel fire-proof corrugated beams resistance in conditions of standard fire tests. Indicators of fire safety are also established in the assessment of design limits of steel fire-proof corrugated beams during design process, construction or maintenance of the building as well as in reducing economic costs when testing steel structures for fire resisting property. The suggested methodology introduces the system of actions aimed to design constructive fire protection of steel corrugated beams of buildings. Technological effect is achieved by conducting firing tests of steel construction by non-destructive methods; the evaluation of fire resistance of fire-proof elements of corrugated beams (corrugated web, upper and lower shelves) is identified by the least fire-proof element of a welded Ibeam. In this methodology fire resistance duration of the constituent elements of a welded I-beam with account of its fire protection ability is described with an analytic function taken as variables. These variables are intensity strength of stresses and the degree of fire protection of a compound element.

One of the main tasks in the calculation of reinforced concrete elements is the determination of strength. This problem is relevant for structures in various stress-strain states - bending, eccentrically-compressed, eccentrically-stretched, eccentrically-compressed with torsion, etc. This article discusses the solution of the strength problem in the design of an eccentrically compressed reinforced concrete element of rectangular cross section with symmetrical reinforcement. The improvement relates to taking into account the infl uence of structural parameters of the quality of reinforcement and concrete on the value of the design loads and the ultimate tensile strength of an eccentrically compressed reinforced concrete element, taking into account its deflection. By simplifying the mathematical description of the influence of structural indicators and quality parameters of reinforcement and concrete on the calculated value of the bending moment and on the strength of an eccentrically compressed reinforced concrete element, as well as simplifying the calculation of the coefficient of increase in the initial eccentricity of the longitudinal force taking into account the deflection of the compressed reinforced concrete element, this improvement is obtained. Using the proposed formulas in calculating the strength of an eccentrically compressed reinforced concrete element of rectangular cross section allows us to ensure the convergence of the result with the classical version of the calculation with a reduction in labor costs due to the simplicity of the formulas.

Abstract. The paper presents a new resource-saving methodology of determining design fire resistance of composite (steel reinforced-concrete) building constructions. The suggested methodology establishes indicators of fire safety of a building which consist in ensured duration of a steel corrugated wall resistance and of tension and compression composite flange of reinforced concrete building structure in terms of standard heating tests; as well as in the assessment of designed limits of fire resistance of a composite building structure during its design-stage, construction or maintenance of the building; and also in for of fire resistance. The paper introduces an improved algorithm for solving firetechnical tasks in respect to express-calculation of designed fire resistance of composite building structures. The article provides results of a scientific research and the content of its technical effect including resource saving while putting into practice an innovative solution of fire protection and ensure fire-resistance of buildings constructions. The results of this scientific research are recommended for practical application in design organizations and can be used to improve existing regulatory documents for fire safety.

Ключевые слова : железобетонная панель, тер-мические повреждения, устройство усиления, арма-турное изделие, концевые опоры, натяжение армату-ры, технический результат, повышение прочности, повышение жесткости, трещиностойкость, огнестой-кость панели, экономия стали.