Crack width analysis of reinforced concrete under direct tension by finite element method and crack queuing algorithm

2016 ◽  
Vol 126 ◽  
pp. 618-627 ◽  
Author(s):  
A.K.H. Kwan ◽  
F.J. Ma
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.


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 921 (1) ◽  
pp. 012022
Author(s):  
S Kala ◽  
H Parung ◽  
A A Amiruddin

Abstract The length of reinforced concrete blocks varies widely, while in general the reinforcement produced in Indonesia is 12 m. Therefore, the use of reinforcement in a long stretch is done to be connected. The through connection is the most economical connection [2]. Lap splice can be made by overlapping the reinforcement which is touching or separate [3]. Splicing reinforcement can cause the strength of reinforced concrete beams to be reduced or even damaged so that rehabilitation measures are needed which can be in the form of retrofit (repair). Retrofitting with wiremesh and self compacting concrete (SCC) is considered to improve building structures. Reinforcement overlapping on reinforced concrete beams retrofit with wiremesh and self compacting concrete can be analyzed by numerical methods to determine their effect on bending behavior. Now, to analyze a structural behavior, it can be done using finite element method based program. The application of the finite element method is used in several programs, including ABAQUS, ADINA, Atena, ANSYS, etc. This study aims to analyze the overlapping of reinforcement in retrofit reinforced concrete beams against the flexural behavior, overlapping is made at one-third and one-third of the beam span using finite element method based analysis software.


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