scholarly journals Spectral modal modeling by FEM of reinforced concrete framed buildings irregular in elevation

2021 ◽  
Author(s):  
Nehar Kheira Camellia
Keyword(s):  
Reinforced Concrete ◽  
Detrimental Effect ◽  
Urban Infrastructure ◽  
Seismic Loads ◽  
The Finite Element Method ◽  
Calculation Methods ◽  
Dynamic Calculation ◽  
Performance Accuracy ◽  
Irregular Buildings ◽  
Calculation Code

AbstractThe irregular buildings constitute a large part of urban infrastructure and they are currently adopted in many structures for architectural or esthetic reasons. In contrast, the behavior of these buildings during an earthquake generates a detrimental effect on their regularity in elevation which leads to the total collapse of these structures.The objective of this work is essentially to model reinforced concrete framed buildings irregular in elevation subjected to seismic loads by the Finite Element Method (FEM). This modeling aims to evaluate several parameters: displacements, inter-storey drifts and rigidities, using two dynamic calculation methods; one modal and the other spectral modal. The latter is widely used by engineers.For this purpose, a detailed study of the frames which have several setbacks in elevation is carried out to validate the correct functioning of our FEM calculation code in both cases of modal and modal spectral analyses. The performance, accuracy and robustness of the FEM calculation code produced in this study is shown by the good correlation of the obtained results for the treated frames with those obtained using the ETABS software.

scholarly journals NUMERICAL ANALYSIS OF CORRUGATED STEEL PLATE BRIDGE WITH REINFORCED CONCRETE RELIEVING SLAB

2015 ◽  
Vol 22 (5) ◽  
pp. 585-596 ◽  
Author(s):  
Damian BEBEN ◽  
Adam STRYCZEK
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Steel Plate ◽  
Numerical Models ◽  
Experimental Tests ◽  
Bridge Engineering ◽  
Steel Plates ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Rc Slab

The paper presents a numerical analysis of corrugated steel plate (CSP) bridge with reinforced concrete (RC) relieving slab under static loads. Calculations were made based on the finite element method using Abaqus software. Two computation models were used; in the first one, RC slab was used, and the other was without it. The effect of RC slab to deformations of CSP shell was determined. Comparing the computational results from two numerical models, it can be concluded that when the relieving slab is applied, substantial reductions in displacements, stresses, bending mo­ments and axial thrusts are achieved. Relative reductions of displacements were in the range of 53–66%, and stresses of 73–82%. Maximum displacements and bending moments were obtained at the shell crown, and maximum stresses and axial thrusts at the quarter points. The calculation results were also compared to the values from experimental tests. The course of computed displacements and stresses is similar to those obtained from experimental tests, although the absolute values were generally higher than the measured ones. Results of numerical analyses can be useful for bridge engineering, with particular regard to bridges and culverts made from corrugated steel plates for the range of necessity of using additional relieving elements.

scholarly journals MODELS OF BAY REINFORCED CONCRETE ELEMENTS RESISTANCE AT ACTION OF CYCLE PERMANENT SIGN HIGH LEVEL FORCES

2018 ◽  
Vol 1 (50) ◽  
pp. 112-123 ◽  
Author(s):  
V. M. Karpiuk ◽  
A. I. Kostiuk ◽  
Yu. A. Somina
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Physical Models ◽  
Cyclic Loads ◽  
Longitudinal Reinforcement ◽  
Calculation Methods ◽  
Cyclic Action ◽  
High Level ◽  
Creep Deformations ◽  
Concrete Elements

The reinforced concrete span beam structures work with small, middle and large shear spans under the action of cyclic loads of high levels is investigated. It is established that researches of physical models development of bending reinforced concrete elements fatigue resistance to the cyclic action of transverse forces and calculation methods on its base are important and advisable due to following features of said load type: the nonlinearity of deformation, damage accumulation in the form of fatigue micro- and macrocracks, fatigue destruction of materials etc. The key expressions of the concrete endurance limits definition (objective strength), longitudinal reinforcement, anchoring of longitudinal reinforcement, which consists the endurance of whole construction are determined. Also the role and the features of influence of vibro-creep deformations on the change mechanics of stress-strain state of concrete and reinforcement of research elements are investigated.

scholarly journals Fracture of Protective Structures from Heavy Reinforcing Cement During Interaction with High-velocity Impactor

2021 ◽  
Vol 14 (6) ◽  
pp. 779-786
Author(s):  
Pavel A. Radchenko ◽  
◽  
Stanislav P. Batuev ◽  
Andrey V. Radchenko
Keyword(s):  
Reinforced Concrete ◽  
High Velocity ◽  
Solid Mechanics ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Free Surfaces ◽  
Local Fracture Criterion ◽  
Protective Structures ◽  
Concrete Barrier ◽  
Limiting Value

In this work, the fracture of a reinforced concrete barrier made of heavy reinforced ce- ment is numerically simulated during normal interaction with a high-velocity titanium projectile. The projectile has the initial velocity 750 m/s. The problem of impact interaction is numerically solved by the finite element method in a three-dimensional formulation within a phenomenological framework of solid mechanics. Numerical modeling is carried out using an original EFES 2.0 software, which al- lows a straightforward parallelization of the numerical algorithm. Fracture of concrete is described by the Johnson-Holmquist model that includes the strain rate dependence of the compressive and tensile strengths of concrete. The computational algorithm takes into account the formation of discontinuities in the material and the fragmentation of bodies with the formation of new contact and free surfaces. The behavior of the projectile material is described by an elastoplastic medium. The limiting value of the plastic strain intensity is taken as a local fracture criterion for the projectile material. A detailed numerical analysis was performed to study the stress and strain dynamics of the reinforced concrete target and the effect of shock-wave processes on its fracture. The influence of reinforcement on the resistance of a heavy cement target to the penetration of a projectile has been investigated

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.

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