scholarly journals Reinforced Concrete Beam with Light Weight blocks and Steel Fibre added below Neutral Axis

The reinforced concrete is one of the widely used structural materials which have its own major advantages and disadvantages. Its behaviour when provided in various positions in the structural elements like compression, tension, and shear zones has significant impact. Since the concrete is excellent in the compression behaviour, and only a nominal performer in the tension behaviour, steel reinforcement are provided in required zones where tension occurs. Thus in a bending member, below the neutral axis, that is at the tension zone, the concrete acts only as a interface medium between reinforcement that carrying the tension and the concrete above neutral axis carrying compression forces. This concrete is also called as sacrificial concrete. Thus in order to efficiently use the concrete falls under the tension zone, the concrete can be swapped with any suitable lighter or cheaper material or the concrete may be strengthened to carry tensile stresses. In this present study, the concrete below neutral axis is replaced with lightweight ‘aerocon’ block cubes of 8 cu.cm and 64 cu.cm by 20% of volume of concrete and in another specimen, steel fibres are added in the concrete that are below neutral axis by 2% and 3% by weight to improve the local tensile strength of concrete as material The results obtained shows that the aerocon cubes replaced specimens has equivalent performance of the control specimen and the steel fibre added specimen had superior deflection and crack performance than the control specimen.

2018 ◽  
Vol 149 ◽  
pp. 02016 ◽  
Author(s):  
Yehya Temsah ◽  
Ali Jahami ◽  
Jamal Khatib ◽  
M Sonebi

Many engineering facilities are severely damaged by blast loading. Therefore, many manufacturers of sensitive, breakable, and deformed structures (such as facades of glass buildings) carry out studies and set standards for these installations to withstand shock waves caused by explosions. Structural engineers also use these standards in their designs for various structural elements by following the ISO Damage Carve, which links pressure and Impulse. As all the points below this curve means that the structure is safe and will not exceed the degree of damage based on the various assumptions made. This research aims to derive the Iso-Damage curve of a reinforced concrete beam exposed to blast wave. An advanced volumetric finite element program (ABAQUS) will be used to perform the derivation.


Author(s):  
S. O. Chepilko ◽  

Issues of calculating steel-reinforced concrete beams are considered taking into account a nonlinear concrete diagram based on the Sargin formula. The nonlinear system of equations for determination of curvature and neutral axis, which is solved numerically, is written in explicit form. Explicit expressions for determination of other calculated quantities needed for design of steel-reinforced concrete beams are derived. Numerical examples are given. The analysis of accounting nonlinearity in comparison with the linear calculation is carried out.


2021 ◽  
Vol 19 (1) ◽  
pp. 1-10
Author(s):  
Seidulla S. Abdullayev ◽  
Gabit B. Bakyt ◽  
Muslim N. Aikumbekov ◽  
Ivan S. Bondar ◽  
Yerlan T. Auyesbayev

Currently, there are many software systems and environments that allow you to simulate and perform fairly complex and voluminous calculations associated with dynamic effects on structural elements of overpasses. The aim of the article is to make an analysis of a reinforced concrete railway overpass as a whole and its elements separately. The article presents the calculated and experimental data of the forms and frequencies of natural vibrations of reinforced concrete railway overpasses under constant loads and the rolling stock off the span. As a result of the analysis of the tests, it was determined that the effect of the rolling stock passing through the reinforced concrete beam spans of 16.5 m and 23.6 m appears with frequency perturbations that are in the range f = 4.41 ÷ 9.52 Hz. These studies can be further used in the design of artificial structures, as well as to identify defects in structural elements of railway bridges.


2020 ◽  
Vol 3 (4) ◽  
pp. 216-228
Author(s):  
K. Senthil ◽  
Iwansh Gupta ◽  
S. Rupali ◽  
Loizos Pelecanos

An explosion on the elevated structures caused by terrorist activities or manmade events can induce significant deformations in the Civil Engineering structures. Therefore, it is necessary to review the response of the structural behavior such as reinforced concrete slab, reinforced concrete beams, and columns. On the basis of this objective, a detailed literature review is conducted to understand the scope for protecting such structures and the structural behavior under blast loading. Based on the detailed literature survey, the investigations about the behavior of conventional reinforced concrete columns and slab initiated in 2005 however, the behavior of reinforced concrete beam was focused since the year 2010. Also, the literature reveals that the investigations on structural elements using analytical techniques are limited in comparison to experiments and simulations. In addition to that, the response of the structural elements was predicted and the trend was calibrated and fitted logarithmically with the experimental results. The predicted spall diameter in the reinforced concrete slab is 0.95 m corresponding charge weight of 100 kg however the influence of spalling was found to be negligible after the 100 kg of charge weight. The predicted spall length in the reinforced concrete beam is 1.6 m corresponding charge weight of 100 kg and the effect may be negligible after 100 kg of charge weight. The predicted deflection in the reinforced concrete columns is 30 mm corresponding to a peak reflected impulse of 1000 MPa-ms, whereas the deflection was found to be negligible after the 1000 MPa-ms of peak reflected impulse.


2018 ◽  
Vol 251 ◽  
pp. 02040
Author(s):  
Anna Malakhova

The article describes the process and causes of cracking of bearing reinforced concrete structures, revealed during the inspection of the technical condition of structural elements of buildings at the stage of their erection, at the stage of suspended construction and in the operational stage. The reasons for the appearance of cracks in reinforced concrete structures under force loads and climatic influences are analyzed. Possible reasons for the appearance of cracks in a monolithic reinforced concrete beam ceiling of a multi-storey building of a column structural system and in monolithic walls of an underground cylindrical reservoir, identified by the author of the article when inspecting the technical condition of these structures, are given. The relationship between the appearance of destructive cracks and the design errors of a monolithic reinforced concrete beam ceiling is shown. The complex nature of the causes of the appearance of cracks in the monolithic walls of the underground reservoir is revealed. The article describes the capabilities of the LIRA-CAD software package for determining the pattern and parameters of fracture-formation of reinforced concrete structures for subsequent comparison with the results of an inspection of the technical condition of structural elements of buildings and structures.


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