Journal•ISSN: 2073-7416
Stroitelʹstvo i rekonstrukciâ
Orel State University
About: Stroitelʹstvo i rekonstrukciâ is an academic journal published by Orel State University. The journal publishes majorly in the area(s): Computer science & Engineering. It has an ISSN identifier of 2073-7416. Over the lifetime, 83 publications have been published receiving 17 citations.
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TL;DR: In this article , the deformation diagrams of uncompressed and undamaged sections were analyzed and the results obtained as a result of the study of the nature of deformation stress of damaged and non-corroded structures according to the parameter ne-1 / r (curvature).
Abstract: There are practically no results of experimental studies of elements made of compressed reinforced concrete damaged by corrosion in the scientific literature. As a result, it is almost impossible to reliably assess the state of deformation-deformation of these structures, especially under dynamic loads. For experimental studies, 37 samples of reinforced concrete were made-columns of square cross-section with dimensions of 100x100 mm, height of 700 mm. Local corrosion damages of concrete and reinforcement were created in reinforced concrete samples, while a concentrated (37%) hydrochloric acid (HCL) solution was used as an aggressor to accelerate the corrosion of elements. The article describes experimental studies on changing the dynamic properties of reinforced concrete elements that undergo corrosion during eccentrically compression. Based on strain gauge data, it was found that corrosion damage leads to a decrease in the height of the compressed concrete section by reducing the cross-section of the stretched reinforcing bars, as well as to the lack of joint work of reinforcing bars with concrete. According to strain measurement data, deformations of uncompressed and undamaged sections were obtained, which showed that the deformation diagrams fundamentally differ in their contour. The results obtained as a result of the study of the nature of deformation of reinforcement and concrete allowed us to assess the state of deformation stress of damaged and non-corroded structures according to the parameter ne-1 / r (curvature). The effect of corrosion damage on the nature of destruction of eccentrically compressed elements has been established.
4 citations
TL;DR: In this paper , the stability of a thin-web steel girder under the combination of patch and shear loading by finite element modelling is investigated. But the results of the analysis are limited and have a limited scope of application.
Abstract: Thin-web steel girders attract with their efficiency in bending work. For such girders, the issue of ensuring local stability becomes very relevant. Calculation formulas in most cases are complex and have a limited scope of application. While the calculations based on FE models make it possible to more universally consider all the specifics of the designed element. The article deals with the calculation of the stability of the web girder under the combination of patch and shear loading by finite element modelling. Numerical models have been created and a comparative analysis with experimental results has been carried out. A description of the principles for constructing FE models (mesh size, material model, etc.), which must be observed when assessing the resistance and behaviour of beams with thin web, is presented. Sensitivity analysis of the FE model to the input parameters revealed the most important parameters (yield strength of steel, web thickness), the uncertainty of which must be taken into account when creating FE models. The convergence of the results allows the use of the finite element method in the design of steel beams for a qualitative and quantitative assessment of the resistance. However, further development of unified principles for creating FE models and their verification on a larger amount of experimental data is required, as well as the determination of partial factors to take into account the variability and uncertainty of the results obtained, taking into account the regulated reliability parameters.
2 citations
TL;DR: In this paper , the authors provided the analysis of the causes of damage in the masonry of historical buildings after their restoration and found that the use of mortars of an increased grade and, accordingly, stiffness during repairs of historical masonry leads to an increase in tensile stresses in bricks under temperature and humidity effects.
Abstract: The article provides the analysis of the causes of damage in the masonry of historical buildings after their restoration. It has been established that the use of mortars of an increased grade and, accordingly, stiffness during repairs of historical masonry leads to an increase in tensile stresses in bricks under temperature and humidity effects. The reasoning behind the use of such mortars is to increase the strength and durability of the restored areas of historical masonry. The results of numerical simulation show that the masonry mortar must be sufficiently strong in compression and, at the same time, sufficiently plastic. It is shown that the use of hard mortars based on a cement binder, compared with plastic mortars based on a lime binder, on average doubles the value of normal tensile stresses at a temperature difference ∆Т=+100С.. This effect is much higher when stones swell due to their moisture. According to the results, for restoration work with brickwork, one should use mortars in accordance with the technology corresponding to this historical period, i.e., lime with additives that were identified during laboratory tests of samples taken from historical masonry. Low-grade mineral solutions with a low modulus of elasticity are preferable. It increases the crack resistance of the masonry under temperature and humidity effects. The article also shows that improper jointing of masonry joints facilitates the destruction of masonry. It happens when areas of accumulation of rainwater are formed, leading to increased wetting of stones in areas of direct impact of rainfall.
2 citations
TL;DR: In this paper , a quality index of the coefficient grid inverse Cauchy problem for beams in building structures is proposed, which is based on the theory of regularization of inverse problems.
Abstract: A quality index of the coefficient grid inverse Cauchy problem for beams in building structures is proposed. The indicator is based on the theory of regularization of inverse problems. An articulated support of a beam on a column is modeled analytically and by a full-scale experiment. Models of measurement and calculation are investigated for a uniform continuous error rate of deflection measurement and calculation of beam identification parameters. Models differ in various combinations of types of external load. A measure of the influence of the error of the measuring instrument and the distribution of approximation grid nodes on the error in determining the coefficients of the beam deflection equation with a fixed first coefficient is proposed. The measure of influence is described by the dimensionless absolute condition number of the problem. The values of the dimensionless absolute condition number and the quality index of the problem are analyzed depending on the distribution of approximation grid nodes, the error of the measuring instrument, and the type of measurement and calculation model. It is proposed to use the obtained analytical dependencies for the analysis of building structures at the stage of experimental and theoretical studies.
2 citations
TL;DR: In this paper , a method of experimental and numerical studies of reinforced concrete frame structures with crossbars reinforced with inclined rods under special influences is given, and the main objective of these studies was to determine the nature of deformation, cracking and destruction of such structures under special impact caused by the sudden removal of one of the structures and, as a consequence, the redistribution of force flows in them.
Abstract: The method of experimental and numerical studies of reinforced concrete frame structures with crossbars reinforced with inclined rods under special influences is given. The main objective of these studies was to determine the nature of deformation, cracking and destruction of such structures under special impact caused by the sudden removal of one of the structures and, as a consequence, the redistribution of force flows in them. To increase the survivability and protection of the studied structural system from progressive collapse, with a quantitative and qualitative change in the forces in its elements, it is proposed to install transverse reinforcement from inclined reinforcing rods in two mutually perpendicular directions on the supporting sections of the frame system crossbars. The parameters of such reinforcement and the parameters embedded in the design model of the frame structure under consideration for static loading at the first stage and dynamic loading at the second stage are determined by numerical modeling using the Ansys software package. On this basis, the justification of the adopted design decisions of frame structures for the development of a program for conducting experimental studies of such structures under special influences was carried out.
1 citations