Parametric Analysis of Reinforced Concrete Columns Under Axial and Shear Loading Using the Finite Element Method

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.

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Seismic collapse analysis of reinforced concrete framed structures using the finite element method

Earthquake Engineering & Structural Dynamics ◽

10.1002/eqe.313 ◽

2003 ◽

Vol 32 (13) ◽

pp. 2027-2046 ◽

Cited By ~ 32

Author(s):

Daigoro Isobe ◽

Michihiro Tsuda

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Reinforced Concrete ◽

The Finite Element Method ◽

Framed Structures ◽

Collapse Analysis ◽

Seismic Collapse ◽

Element Method

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Analysis of Structure Displacement Formed as a Result of Torsion in Case of Using Rubber-Metal Seismic Isolators

Journal of Architectural and Engineering Research ◽

10.54338/27382656-2021.1-10 ◽

2021 ◽

Vol 1 (2) ◽

pp. 10-15

Author(s):

Hovhannes Armen Avagyan ◽

Arman Sevak Margaryan

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Reinforced Concrete ◽

Seismic Isolation ◽

The Finite Element Method ◽

Complex Planning ◽

Element Method

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.

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Changes in the stiffness of load-bearing elements of a high-rise building and inclinometer data based on finite element analysis

E3S Web of Conferences ◽

10.1051/e3sconf/202126302023 ◽

2021 ◽

Vol 263 ◽

pp. 02023

Author(s):

Alexey Plotnikov ◽

Mikhail Ivanov

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Reinforced Concrete ◽

Automatic Monitoring ◽

Physical Parameters ◽

The Finite Element Method ◽

Element Analysis ◽

Reinforcing Bar ◽

High Rise ◽

Element Method

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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