Strength of Reinforced Concrete Chambers Under External Pressure

1975 ◽  
Vol 97 (4) ◽  
pp. 309-314 ◽  
Author(s):  
O. Buyukozturk ◽  
P. V. Marcal
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Special Reference ◽  
External Pressure ◽  
General Purpose ◽  
The Finite Element Method ◽  
Cylindrical Tank ◽  
Geometric Imperfection ◽  
Cylindrical Tanks

A study was made to establish the strength of concrete chambers subjected to external pressure with special reference to the reinforced concrete cylindrical tanks. The finite element method as implemented in a nonlinear general purpose program produced analytical results which agreed with the experiment. The study concluded that the cylindrical tank was weakened in buckling by 20 percent due to geometric imperfection, 10 percent due to creep and 6 percent due to reinforcements. The main failure mode of the shell was compression shear.

scholarly journals MODAL ANALYSIS OF REINFORCED CONCRETE AND FIBER CONCRETE BEAMS

2021 ◽  
Vol 3 (1) ◽  
pp. 95-105
Author(s):  
T. Makovkina ◽  
◽  
M. Surianinov ◽  
O. Chuchmai ◽  
◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Computer Modeling ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
The Finite Element Method ◽  
Fiber Concrete ◽  
Experimental Researches ◽  
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.

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

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.

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

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.

FEATURES OF THE METHODOLOGY FOR CALCULATING BUOYANCY AND STRENGTH OF A BLOCK PONTON FOR VERTICAL CYLINDRICAL TANKS

2020 ◽  
Author(s):  
Aleksandr Safonov ◽  
Vitaliy Shkaberin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Oil Products ◽  
The Finite Element Method ◽  
Cylindrical Tanks ◽  
Sufficient Strength ◽  
Element Method

The paper considers a technique for analyzing the strength and buoyancy of block pontoons for vertical cylindrical tanks used for storing liquid oil products. A model is proposed for performing calculations by the finite element method of a pontoon for buoyancy and strength, taking into account the action of pushing forces. The results of calculations on strength and buoyancy of an aluminum pontoon with foam-urethane filling BPA5000 are presented. It has been established that BPA5000 pontoons have sufficient strength and buoyancy, as regulated by GOST 31385-2016.

General Instability of Swedge-Stiffened Circular Cylinders Under Uniform External Pressure

1993 ◽  
Vol 37 (01) ◽  
pp. 77-85
Author(s):  
C. T. F. Ross ◽  
A. Palmer
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Finite Element ◽  
Theoretical Analysis ◽  
External Pressure ◽  
Reduction Factor ◽  
Circular Cylinders ◽  
The Finite Element Method ◽  
Uniform External Pressure ◽  
Thinness Ratio

A theoretical and experimental investigation into the general instability of nine swedge-stiffened circularcylinders under uniform external pressure is described. The investigation found that most of the vesselssuffered plastic general instability, and that initial out-of-roundness played a significant role in the magnitude of the elastic knockdown. The theoretical analysis was based on the finite-element method, and a thinness ratio is proposed from which one can determine a plastic reduction factor when more experimental results are available.

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