scholarly journals Calculation of load-bearing capacity of prestressed reinforced concrete trusses by the finite element method

Author(s):  
Vladimir Agapov ◽  
Roman Golovanov ◽  
Kurban Aidemirov
2018 ◽  
Vol 64 (4) ◽  
pp. 89-103
Author(s):  
A. Nesterenko ◽  
G. Stolpovskiy ◽  
M. Nesterenko

AbstractThe actual load-bearing capacity of elements of a building system can be calculated by dynamic parameters, in particular by resonant frequency and compliance. The prerequisites for solving such a problem by the finite element method (FEM) are presented in the article. First, modern vibration tests demonstrate high accuracy in determination of these parameters, which reflects reliability of the diagnosis. Secondly, most modern computational complexes do not include a functional for calculating the load-bearing capacity of an element according to the input values of resonance frequencies. Thirdly, FEM is the basis for development of software tools for automating the computation process. The article presents the method for calculating flexural stiffness and moment of inertia of a beam construction system by its own frequencies. The method includes calculation algorithm realizing the finite element method.


2020 ◽  
Vol 30 (4) ◽  
pp. 33-47
Author(s):  
Krzysztof Wierzbicki

Abstract The study presents an analysis of steel I-beam warping. The calculations were made for hot-rolled IPE200 hinged beams with different lengths. After determining load-bearing capacity using the GMNIA method, the beams were strengthened with bimoment restraints at each end. The changes in critical moment and load-bearing capacity were then evaluated. The study presents the manner in which the material and geometric imperfections have been determined. The GMNIA calculations were conducted using the Finite Element Method in Abaqus software. The results were then compared to results obtained with traditional methods and acquired from LT Beam software.


2014 ◽  
Vol 8 (1) ◽  
pp. 326-331 ◽  
Author(s):  
Dengfeng Wang ◽  
Yongfu Yu ◽  
Licheng Pan ◽  
Haijin Dai

For some electrostatic precipitators, profiled steel sheets are used as casing wall which is subjected to both bending and vertical compression. By nonlinear finite element method, the influences of structural parameters on load bearing capacity of profiled steel sheet wall were investigated. For the loading path, the uniform transversal pressure was applied firstly, and then the vertical compression was applied until the wall failed. The results indicate that the vertical compression resistance of profiled sheet decreases with the transversal load or the increasing sheet span. For certain sheet shape, the vertical compression resistance of profiled sheet decreases with the wall width increasing. The vertical resistance of the profiled sheet whose tensioned flanges are connected with the side columns is more than that whose compressed flanges are connected with the side columns. When the vertical compression resistance is calculated according to the buckling evaluation method of cold-form thin-walled steel member, the value is usually less than the solution from finite element method. Consequently, the load bearing capacity based on the related method of cold-form thin-walled steel member can be taken as a reference solution for the profiled steel sheet subjected to combined bending and vertical compression.


2021 ◽  
Vol 3 (1) ◽  
pp. 95-105
Author(s):  
T. Makovkina ◽  
◽  
M. Surianinov ◽  
O. Chuchmai ◽  
◽  
...  

Analytical, experimental and numerical results of determination of natural frequencies and forms of oscillations of reinforced concrete and fiber concrete beams are given. Modern analytical, numerical and experimental methods of studying the dynamics of reinforced concrete and fiber concrete beams are analyzed. The problem of determining the natural frequencies and forms of oscillations of reinforced concrete and fiber concrete beams at the initial modulus of elasticity and taking into account the nonlinear diagram of deformation of materials is solved analytically. Computer modeling of the considered constructions in four software complexes is done and the technique of their modal analysis on the basis of the finite element method is developed. Experimental researches of free oscillations of the considered designs and the comparative analysis of all received results are carried out. It is established that all involved complexes determine the imaginary frequency and imaginary form of oscillations. The frequency spectrum calculated by the finite element method is approximately 4% lower than that calculated analytically; the results of the calculation in SOFiSTiK differ by 2% from the results obtained in the PC LIRA; the discrepancy with the experimental data reaches 20%, and all frequencies calculated experimentally, greater than the frequencies calculated analytically or by the finite element method. This rather significant discrepancy is explained, according to the authors, by the incorrectness of the used dynamic model of the reinforced beam. The classical dynamics of structures is known to be based on the theory of linear differential equations, and the oscillations of structures are considered in relation to the unstressed initial state. It is obvious that in the study of free and forced oscillations of reinforced concrete building structures such an approach is unsuitable because they are physically nonlinear systems. The concept of determining the nonlinear terms of these equations is practically not studied. Numerous experimental researches and computer modeling for the purpose of qualitative and quantitative detection of all factors influencing a spectrum of natural frequencies of fluctuations are necessary here.


2014 ◽  
Vol 577 ◽  
pp. 1097-1103
Author(s):  
Tian De Jin ◽  
Lan Hui Guo

In this paper, the behavior of composite stub columns under different loading conditions is studied using the finite element method. The accuracy of the theoretical method is validated by comparing with the experimental results. The behavior of specimen under different loading conditions is analyzed. Then, based on the finite element method, the comparison of mechanical behavior under three typical loading conditions is studied. The results show that the difference on bearing capacity will become larger with the increase of steel area to concrete area ratio. For the core concrete loaded specimen with lower steel area-to-concrete area ratio, whose bearing capacity is the lowest, but its ductility is very good. With the increase of the steel yield strength, the bearing capacity will increase evidently for specimen loaded simultaneously. While for the specimen with only core concrete loaded, the steel yield strength has little influence except increase of ductility.


2021 ◽  
Vol 1 (2) ◽  
pp. 10-15
Author(s):  
Hovhannes Armen Avagyan ◽  
Arman Sevak Margaryan

The study of a building with a complex planning solution, rubber-metal laminated seismic isolation supports (hereinafter referred to a RMLSIS) placed at the foundation level and with a reinforced concrete frame-braced system is presented, taking into account the displacement of the structure formed as a result of torsion. The analyses were conducted with the finite element method. The calculation schemes were modeled using the "Lira-SAPR" software. The displacement of the structure formed as a result of torsion of buildings having the same planning solution, different number of floors as well as with and without RMLSIS is estimated. The results obtained show that the displacement values of the structure formed as a result of torsion increased about 40% in buildings without RMLSIS and 25% in buildings with RMLSIS.


2021 ◽  
Vol 263 ◽  
pp. 02023
Author(s):  
Alexey Plotnikov ◽  
Mikhail Ivanov

The use of monitoring techniques during the operation of a building contributes to the study of the stress-strain state of both known and newly developed structural systems. The article discusses the effect of reducing the bending stiffness of reinforced concrete crossbars of high-rise buildings on the overall deformability, which can be monitored by changing the angles of rotation at characteristic points. For the introduction into the model of the calculation based on finite elements of the physical parameters of the stiffness of reinforced concrete bending elements, the function of the change in the shoulder of a pair of forces in the section during the opening of normal cracks is given. Empirical data on changes in the stress unevenness coefficient along the length of the reinforcing bar are used. The calculation is based on the diagrammatic method. The data on the accumulated experience of measuring the angles of rotation of a building with automatic monitoring of buildings are presented. Using the finite element method, the systems were simulated with a decrease in stiffness to 0.4 from the initial one. It is shown that it is possible to select a range of sensors - angle meters - inclinometers. It has been determined that the angle of rotation can be changed up to 1.6 times. The corresponding ranges are defined for two types of frameworks: frame and frame-braced. The nature of the change in the overall stiffness of the building frame as a result of reducing the stiffness of the crossbars is shown. Calculation models based on the finite element method determined the deformation limits of the entire frame as a whole.


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