Vladimir Mushchanov
To the Analysis of the Main Provisions of Regulatory Documents for the Prevention of Progressive Collapse of Building Structures (part 2)
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article analyzes the main regulatory documents in force in the post-Soviet space of the CIS countries, the countries of the European Union, the USA, Great Britain, within which design procedures are considered aimed at preventing the development of progressive collapse. Different approaches are compared and analyzed in the formulation of the considered design situations, constructive solutions, to the bearing capacity criteria, parameters of buildings and structures, which are subject to the requirements for the development of measures that exclude the development of progressive collapse. A critical assessment of constructive techniques aimed at preventing the development of progressive collapse in the frame structures of multi-storey buildings, regulated by regulatory documents, has been carried out. In addition to this, an analysis of the main scientific studies aimed both at preventing the development of an avalanche collapse and at solving related problems (increasing survivability, reducing the probability of failure, etc.) was carried out. On the basis of the analysis carried out, actual tasks are formulated, on which researchers working in this direction should focus their attention.
Keywords: progressive collapse, buildings and structures, regulatory documents.
Valentin Penchuk, Vladimir Sidorov
Structural Assessment of the Metal Structures of the Hoist Incline of the Furnace Hoisting Machine of the Blast Furnace During Operation
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper considers the issues of assessing the condition of the metal structures of the hoist incline of the furnace hoisting machine, which is widely used in the mining, metallurgical and construction industries. Long service life, the effects of cyclic variable loads, vibration and environmental influences lead to local damage of the structural elements. The study of two approaches to the analysis of the acting forces and destructive factors on the elements of the hoist incline of the furnace hoisting machine of the blast furnace is carried out. The data obtained during the visual inspection of metal structures allow us to indirectly assess the values of the acting forces and the nature of external influences. A 3D model of the hoist incline of a furnace hoisting machine has been developed, reactions in the slopes of the skips have been calculated, and a dynamic mathematical model of the power loading of ropes has been considered. The data obtained make it possible to clarify the causes of accelerated wear of hoist incline elements at the points of reinforcement. On the existing equipment, measurements of the parameters of mechanical vibrations at various levels of the metal structure of the inclined bridge were carried out, during the passage of the skip – as the main source of load. The obtained values of the time realization of vibration acceleration make it possible, based on the analysis of the data obtained, to determine the stability or degradation of the state, to identify the moment of the appearance of the first deviations and to prevent the development of damage by carrying out restorative repairs.
Keywords: hoist incline, furnace hoisting machine, blast furnace, technical condition, vibration.
Sergey Titkov
Experimental Study of the Wind Effect on a Frame-Sheathed Metal Pyramidal Cooling Tower in a Wind Tunnel, Taking into Account the Installation Stages
Donbas National Academy of Civil Engineering and Architecture
Abstract. Тhe article presents the results of a study of the wind impact on a dodecahedral frame-sheathed metal cooling tower of a pyramidal shape. Experimental studies mean a series of studies that complement each other and help build the course of further research, complete the data or refute the hypotheses and prerequisites for wind flow around buildings and structures. The results of the conducted drainage experiments on finding the local Сpi coefficients in the characteristic sections of the tested model along the inner and outer contours of the cooling tower are presented. The results of the qualitative experiments on the visualization of the wind effect by the laser knife method. This work was carried out in order to find diagrams of the wind effect on the pyramidal frame-sheathed metal cooling tower, taking into account the seasonal operation of this structure, as well as during the installation period from closing to closing the tier contour to identify the most unfavorable design situations of the influence of wind action.
Keywords: metal cooling tower, hyperbolic shape, load-cell scales, local coefficient, velocimetry, shadow method.
Vladimir Vasylev, Andrey Mironov, Vladimir Anishchenkov, Dimitriy Ignatenko
Experimental Studies of the Combined Action of a Steel Element and Concrete on the Surface of their Contact
Donbas National Academy of Civil Engineering and Architecture
Abstract. Static tests of prisms made of concrete of class B15 are considered in order to study the adhesion of concrete on the flat surface of a steel element. To conduct experimental studies, an installation was created consisting of two metal plates with dimensions of 500×100×10 mm, between which concrete prisms were placed and then compressed with a hydraulic press. Concrete prisms were installed on a metal square slab with dimensions of 100×100 mm. The load on the ends of the prisms was transmitted by a GD-20 hydraulic jack with a load capacity of 20 tons through a round metal cover plate with a diameter of 200 mm and a metal cylinder Ø50×135 mm. Horizontal deformations of concrete prisms that occur along the force generated by the jack were recorded by a clock–type IR-10 indicator with an entry in the laboratory test log. The purpose of the tests was to study longitudinal horizontal shear deformations along the concrete-steel contact, depending on the level of compression of the concrete prism and the level of applied load to the cross section, as well as to determine the coefficient of friction of rest on the contact surfaces of the two materials.
Keywords: experimental model, stress-strain state (SST), pipe-concrete (PC) element, hydraulic press, hydraulic jack (HJ), load, concrete prisms, concrete adhesion, coefficient of friction of concrete at rest on a steel surface.