scholarly journals Comparative analysis of reinforced concrete tee beams reinforcement methods

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Danil Baldin ◽  
Andrey Kraev ◽  
Erkn Zhaisambaev
Keyword(s):  
Composite Material ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Structures ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Advantages And Disadvantages ◽  
Amplification Method ◽  
Extended Zone

Due to the increase in requirements for transport facilities, there is a need to strengthen them. The article is devoted to the analysis of reinforcement methods for load-bearing reinforced concrete structures of transport structures. The author notes in what period of the bridge’s life, it needs reinforcement, what difficulties are associated with reinforcing structures, and what are the main amplification methods that exist today. In order to select the optimal amplification method, it is necessary to carry out verification calculations, study the zone requiring amplification, take into account how many times the load-bearing capacity will increase and whether additional force effects will occur. This article describes the advantages and disadvantages of reinforcing by welding additional reinforcement and bonding composite material. The author calculated the amplification of the extended zone of the T-section reinforced concrete beam of the superstructure with additional reinforcement and composite materials. Based on the calculations made, recommendations have been put forward on the relevance of using one or another method of reinforcing the structure.

scholarly journals Load Bearing Capacity Calculation of the System “Reinforced Concrete Beam – Deformable Base” under Torsion with Bending

2019 ◽  
Vol 97 ◽  
pp. 04059 ◽  
Author(s):  
Alexey Dem’yanov ◽  
Vladymir Kolchunov ◽  
Igor Iakovenko ◽  
Anastasiya Kozarez
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Concrete Beam ◽  
Equations Of State ◽  
Reinforced Concrete Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Deformable Base ◽  
The Relationship

It is presented the formulation and solution of the load bearing capacity of statically indeterminable systems “reinforced concrete beam – deformable base” by spatial cross-sections under force and deformation effects. The solution of problem is currently practically absent in general form. It has been established the relationship between stresses and strains of compressed concrete and tensile reinforcement in the form of diagrams. The properties of the base model connections are described based on a variable rigidity coefficient. It is constructed a system of n equations in the form of the initial parameters method with using the modules of the force (strain) action vector. The equations of state are the dependences that establish the relationship between displacements which are acting on the beam with load. Constants of integration are determined by recurrent formulas. It makes possible to obtain the method of initial parameters in the expanded form and, consequently, the method of displacements for calculating statically indefinable systems. The values of the effort obtained could be used to determine the curvature and rigidity of the sections in this way. It is necessary not to set the vector modulusP, the deformation is set in any section (the module is considered as an unknown) during the problem is solving. This allows us to obtain an unambiguous solution even in the case when the dependence M–χ has a downward section, i.e one value of moment can correspond to two values of curvature.

scholarly journals Strengthening Solutions for Deep Reinforced Concrete Beam with Cutout Opening

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 370
Author(s):  
Alireza Bahrami ◽  
Felicia Ågren ◽  
Kim Kollberg
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Deep Beam ◽  
Rc Buildings ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Existing Building ◽  
Door Opening ◽  
Design Software

Since reinforced concrete (RC) buildings have long service life, cutout openings are generally needed in their load-bearing walls as a sustainable solution in order to meet new requirements of their users. However, the cutout openings decrease the load-bearing capacity of the walls, which may result in the failure of the buildings. In this paper, we investigate the possibility of making a door opening in a load-bearing RC wall of an existing building in Gävle in Sweden. The wall studied in the current paper rests on two individual supports at its two ends; thus, it is considered as a deep beam. However, it is called an examined wall (EW) here. The StruSoft FEM-Design software is used in this study to model, analyze, and design the building based on the Eurocodes and Swedish national annex. The potential need for the EW to be strengthened when the cutout opening is made is also evaluated. It is concluded that strengthening the EW with cutout opening is needed. Different strengthening solutions are proposed for the EW. Moreover, the situation of the EW with the solutions is assessed with regard to the utilization ratio, deflection, and weight. Consequently, it is demonstrated that the proposed strengthening solutions function well for the EW.

scholarly journals Crack Detection of Reinforced Concrete Structures Based on BOFDA and FBG Sensors

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Qinghua Zhang ◽  
Ziming Xiong
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Crack Detection ◽  
Concrete Structures ◽  
Lower Surface ◽  
Reinforced Concrete Beam ◽  
Sensor Data ◽  
Reinforced Concrete Structures ◽  
Surface Cracks ◽  
Fbg Sensors

Reinforced concrete structural elements, as an important component of buildings and structures, require inspection for the purposes of crack detection which is an important part of structural health monitoring. Now existing crack detection methods usually use a single technology and can only detect internal or external cracks. In this paper, the authors propose a new sensing system combining BOFDA (Brillouin optical frequency-domain analysis) and FBG (fiber Bragg grating) technology, which are used to detect internal and surface cracks and their development in reinforced concrete structures, and an attempt is made to estimate the width of surface cracks. In these experiments, a special reinforced concrete beam structure was designed by the author for crack detection under load. Four continuous distributed optical fibers are fixed on the steel skeleton, which is located within the reinforced concrete beam. Three FBG sensors are fixed on the lower surface of the beam, near its centre. By analysing the sensor data, it can be found that the BOFDA-distributed fiber can be used to detect internal cracking before surface cracking, and the difference between scans can be used to judge the time of onset of internal cracking, but the relative error in position is about 5%, while the FBG sensor can detect the cracking time of microcracks on the lower surface in near-real-time and can be used to calculate the crack width. Through the experiment, it is found that if the combination of BOFDA and FBG technology is adopted, we can initially use the strain data obtained by multiple groups of BOFDA monitoring to predict the general location of the internal cracks, then to monitor the exact location of the surface cracks by FBG in the medium term, and to estimate the width of the final expansion of the cracks finally.

scholarly journals Seismic Behaviour of Exterior Reinforced Concrete Beam-Column Joints in High Performance Concrete Using Metakaolin and Partial Replacement with Quarry Dust

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
G. R. Vijay Shankar ◽  
D. Suji
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
High Performance ◽  
Concrete Beam ◽  
High Performance Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Partial Replacement ◽  
Displacement Curve ◽  
Reinforced Concrete Structures

Recent earthquakes have demonstrated that most of the reinforced concrete structures were severely damaged; the beam-column joints, being the lateral and vertical load resisting members in reinforced concrete structures, are particularly vulnerable to failures during earthquakes. The existing reinforced concrete beam-column joints are not designed as per code IS13920:1993. Investigation of high performance concrete (HPC) joints with conventional concrete (CC) joints (exterior beam-column) was performed by comparing various reinforcement detailing schemes. Ten specimens were considered in this investigation and the results were compared: four specimens with CC (with and without seismic detailing), four specimens with HPC (with and without seismic detailing), and two specimens with HPC at confinement joint. The test was conducted for lateral load displacement, hysteresis loop, load ratio, percent of initial stiffness versus displacement curve, total energy dissipation, strain in beam main bars, and crack pattern. The results reveal that HPC with seismic detailing will be better compared with other reinforcements details under cyclic loading and reverse cyclic loading.

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

2019 ◽  
Vol 9 (2) ◽  
pp. 4214-4218
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Steel Fibre ◽  
Shear Zones ◽  
Reinforced Concrete Beam ◽  
Neutral Axis ◽  
Control Specimen ◽  
Tension Zone ◽  
Structural Elements ◽  
Advantages And Disadvantages

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.

scholarly journals Impact of the fire on the bearing capacity of the ordinary concrete used in reinforced concrete structures in Burundi. History and architecture

Vestnik MGSU ◽  
2021 ◽  
pp. 1567-1572
Author(s):  
Emmanuel Mikerego ◽  
Donatien Nduwimana
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Negative Impact ◽  
Heating Temperature ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Ordinary Concrete ◽  
The Impact

Introduction. This paper presents the results of an assessment of the impact of fire on the bearing capacity of the ordinary concrete, to be taken into account in the rehabilitation of fire-damaged reinforced concrete structures in Burundi. Materials and methods. Experimental samples of the ordinary concrete made respectively of coarse river aggregates and crushed coarse quarry aggregates were prepared and subjected to different heating temperatures (250, 350, 450, 600 and 900 °C) simulating the fire. After natural cooling, experimental samples were subjected to compression test; and diagrams showing the loss of the load-bearing capacity of the ordinary concrete used in reinforced concrete structures in Burundi were drawn. Results. Negative impact of the fire on the load-bearing capacity of the ordinary concrete occurs above of 350 °C of heating temperature. Concrete made of crushed coarse quarry aggregates loses 50 and 78 % of its bearing capacity at around 525 and 900 °C of heating temperature, respectively. Similarly, concrete made of coarse river aggregates loses 50 and 70 % of its load-bearing capacity respectively at 600 and 900 °C of heating temperature. An evaluation curve of the after-fire bea­ring capacity of the concrete used in reinforced concrete structures in Burundi is established. Conclusions. The negative impact of the fire on the load-bearing capacity of the ordinary concrete occurs above of 350 °C of heating temperature. Concretes made of crushed coarse quarry aggregates and concrete made of coarse river aggregates lose 50 % of its bearing capacity at around 525 and 600 °C of heating temperature respectively. Knowing the heating temperature that the fire-damaged reinforced concrete structure has undergone is indispensable in deciding on its demolition or rehabilitation.

Experimental Research on the Change Rule of Frequency of Shale Ceramsite Reinforced Concrete Beam with Damage

2012 ◽  
Vol 204-208 ◽  
pp. 3946-3951
Author(s):  
Wei Jun Yang ◽  
Qiu Kong ◽  
Zhou Ping Yu ◽  
Yi Chun Ren
Keyword(s):  
Reinforced Concrete ◽  
Experimental Research ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Vibration Test ◽  
Reinforced Concrete Structures ◽  
Design And Construction

Taking vibration test on 7 shale ceramsite concrete beams and a reinforced concrete beam, collecting the dynamic signals, and modal analyzing it, this paper studies the ceramsite diameter /strength and the injury at all stages impact on the frequency so as to guide the design and construction of shale ceramsite reinforced concrete structures and components.

scholarly journals Damage and retrofitting monitoring in reinforced concrete structures along with long-term strength and fatigue monitoring using embedded Lead Zirconate Titanate patches

2018 ◽  
Vol 30 (1) ◽  
pp. 100-115 ◽  
Author(s):  
Naveet Kaur ◽  
Suresh Bhalla ◽  
Subhash CG Maddu
Keyword(s):  
Reinforced Concrete ◽  
Lead Zirconate Titanate ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Mode Shapes ◽  
Reinforced Concrete Structures ◽  
Vibration Sensors ◽  
Fatigue Monitoring

This article aims at developing a generic system for the damage and retrofitting monitoring along with long-term strength and first-stage fatigue monitoring of reinforced concrete structures using embedded Lead Zirconate Titanate sensors in the form of concrete vibration sensors. The concrete vibration sensor is a ready-to-use sensor, and its unique packaging renders it very compatible for embedment in reinforced concrete structures. In addition to cost-effectiveness, the concrete vibration sensors are also characterized by excellent structure-compatibility and durability. In this article, both finite element method and experimental investigations have been employed to establish the feasibility of using curvature (second-order derivative) and other higher order derivatives of displacement mode shapes for damage detection and retrofitting assessment. The experiments are conducted on a real-life-sized reinforced concrete beam. The concrete vibration sensors embedded on the outer faces of the reinforced concrete beam are coupled to obtain the curvature and higher order mode shapes of the beam in pristine, damaged and retrofitted conditions. It is found that the curvature mode shape–based response of concrete vibration sensors can successfully identify the location of damage both numerically and experimentally. However, the third-order mode shape is unable to correctly identify the location of damage. Before introducing damage in the beam, the effect of long-term dynamic loading from Day 6 to Day 108 after casting of the reinforced concrete beam is also monitored. Both the global monitoring technique (in which flexural rigidity of the beam is monitored) and the local electro-mechanical impedance technique (where the equivalent stiffness identified by concrete vibration sensors is monitored) successfully detected the decreasing fatigue strength of the reinforced concrete beam. Degradation of the strength of reinforced concrete beam results due to the development of micro-cracks in the concrete because of the continuous vibrations (9.3 million load cycles) experienced by it via shaker. This is the first-of-its-kind proof-of-concept application of equivalent stiffness concept for monitoring curing of a large-sized reinforced concrete structure. It is also the first study on first-stage fatigue monitoring carried out before the ‘retrofitting-stage’ of the structure. Complete experimental investigations after the ‘retrofitting-stage’ covering all three stages of fatigue have been covered by the authors in their related publication.

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