At the present time, it is necessary to strengthen the economy mode, the resources efficiency and reduce the material consumption in construction. Modern building constructions must meet all the requirements of economy, resource conservation, which are required for construction. The main direction of their development is reducing the cost of steel (14-16%), saving cement (10-12%) and saving forest materials (12-14%). These tasks can be solved, including at the expense of reduction of material content and reduction of the cross-section of structures, due to the rational combination of concrete and steel in their joint work and through the use of high-strength materials. These requirements are satisfied with building constructions from tube confined concrete. With a relatively small cross-section, such structures can withstand significant efforts, while the concrete at the expense of a volumetric stressed state receives stresses that far exceed the prism strength, which saves steel and concrete. Applying high-strength concrete, concrete, compacted by pressing, centrifugation, it is possible to obtain significant cement savings, as due to industrial technological factors of sealing concrete mix significantly increases the concrete strength. It is possible to increase the concrete strength also due to the use of indirect reinforcement, which allows, at low cost of steel, to significantly increase the strength of structures. Improving the well-known effective methods of strengthening concrete in relation to tube confined concrete constructions with strengthened cores suitable for industrialization is an urgent and important task. The purpose of the research presented in this paper was the experimental study of tube confined concrete elements with reinforced in different methods concrete cores; the development of methods for calculating the carrying capacity and the stress-strain state of tube confined concrete elements with strengthened cores.

This paper deals with the study of stochastic parameters of external loads, which are used in the tasks of determining the level of reliability of steel storage capacities. To describe the random load process, the normal law and the double exponential distribution of Gumbel were used. It was formulated the technique of transition from the study of the entire random process to the consideration of its maximums. It was obtained quantitative values of the stochastic characteristics of snow and wind loads on the territory of Ukraine, without reference to the zoning maps. A general procedure for determining the probability of failure was formulated, depending from a given characteristic maximum. This index corresponds to the basic level of load. The average intersection of this level by a random load process is equal to one. Analytical formulas are obtained to determine the scale and position of the double exponential distribution of Gumbel, which depend on the characteristic maximum, as well as formulas, which help to calculate the statistical characteristics (standard, expected value and coefficient of variation) of the random value of the load maximums. The possibility of using this approach is theoretically confirmed when the density distribution of the ordinate of a random process follows the normal law. It was proposed expressions for the parameters of the distribution maximums of the random processes, which are described by the polynomial exponent and the Weibull law.

In the article, the results of experimental researches of elements of structural steel reinforced slabs are presented. And the particularities of the work of structural designs under load are identified.

The problems of energysaving are considered in building in number of different manners warming of facades of buildings and structures. The possibilities of the using are offered for new thermalinsulating material “PERVOLIN”.

The article deals with the calculation of steel reinforced concrete columns compression and verification of local stability in fixed formwork. It is concluded that it is expedient to calculate the total stability for the resulted sections, and when checking local stability -to follow the instructions Eurocode 4. When checking the local stability of steel sheets, working as part of reinforced concrete structures, the Eurocode 4 guidelines should be followed, while taking into account the following requirements: leave out of account on the local stability of the concrete cross-section (the steel profile is completely surrounded by concrete); concrete cross-section (steel profile is completely concrete, partially concrete cross-section), the steel profile is only partially covered with concrete, as well as for other cross-sections of reinforced concrete columns provided by Eurocode 4 with the corresponding ratio d/ t. The calculation method for the given sections in the calculation of the overall stability of compressed steel reinforced concrete elements is the simple stand one that gives satisfactory results. Calculations show that the loss of local stability of a steel sheet that works concurrently with reinforced concrete occurs at stresses greater than the force of flow in a steel sheet.