The article analyzes the design solutions for the outer walls of residential buildings built in 2020-2022 in a city that belongs to the II temperature zone of Ukraine. The outer walls of the monolithic reinforced concrete frame of the building are made of hollow brick 250 mm thick with a façade system of heat-insulating and finishing class A. A verification thermotechnical calculation of the outer wall was carried out, taking into account heat-conducting inclusions, the reduced heat transfer resistance of an opaque enclosing structure (wall) does not correspond to the minimum allowable value of heat transfer resistance of the corresponding structure according to DBN V.2.6 – 31:2016 for the II temperature zone. When taking into account the effect of air permeability on reducing the overall level of thermal protection of the fence, it was determined that the calculated reduced value of the resistance to heat transfer of the outer wall will be even lower due to the fact that the structure consists of light cellular materials with a significant breathability. External enclosing structures and internal, dividing rooms with a temperature difference of 4 ° C or more, have insufficient insulation thickness. When developing insulation measures, the effect of air filtration through wall structures made of lightweight materials is not taken into account. The requirements for the insulation of complex structural units of enclosing structures to prevent the formation of "cold bridges", for example, a balcony slab, are not met. Translucent structures, which occupy more than 50% of the facades, are the cheapest, their heat transfer resistance is less than the minimum allowable value. Based on the results of the analysis, the main measures to improve the energy efficiency of residential multi-storey buildings were identified to enable the installation of large windows in residential and public buildings in the climatic conditions of Ukraine.
Stress-strain state and compressed flexible steel-reinforced concrete elements resistance capacity are investigated in the work. The experiment program is complied and steel reinforced concrete elements calculations methods are analyzed. Experimental sample design drawings are shown. Raw materials physical and mechanical properties are determined. Steel reinforced-concrete elements experimental and research studies have been carried out. Coboundary dependences N-M for steel reinforced concrete elements construction method is proposed. Resistance capacity diagrams for steel reinforced concrete elements are constructed depending on the element height and the applied eccentricity.
The article presents the results of experimental tests of compressed tubular elements with demountable joints investigated on the central and noncentral compression (with eccentricities 0, 0,25 and 0.5 from the diameter of the sample) and numerical simulation by the finite element method. The obtained results were compared for similar samples and their models. For which using numerical simulation in the Femap software system a stress-strain state was investigated and graphical representations of principal stresses were presented. For comparison the tensions that arose when the shell's steel pipe was reached the yield strength were selected. The mean square deviation and the coefficient of variation of the data obtained varied in the range of 5 – 7%, which indicates the correspondence of the results and allows further research of partial replacement of experimental tests with numerical simulation
The stress-strain state and the bearing capacity of the dismountable joints of concrete filled tubular elements are investigated. The methods of calculation and constructive solutions of concrete filled tubular elements with joints are analyzed. Five new types of dismountable joints are proposed. Experimental studies of concrete filled tubular elements have been carried out. It was determined that the most effective for compression was a joint with a steel coupling and for bending the most effective was a joint with longitudinal ribs. The numerical modeling algorithm is presented; results are verified using experimental tests. A method for constructing N-M boundary dependences for concrete filled tubular structures is proposed. Bearing capacity diagrams for concrete filled tubular elements and their joints have been constructed. The costs of the materials needed to perform the joint as the example of a real construction for similar loads are analyzed.
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