Behavior of Pre-Cracked Reinforced Concrete Beam Strengthened with Prestressed CFRP Plate

2013 ◽  
Vol 351-352 ◽  
pp. 1397-1403
Author(s):  
Bo Wang ◽  
Hui Peng ◽  
Jian Ren Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reference Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Structures ◽  
Cracked Beam ◽  
Cfrp Plate ◽  
Load Carrying ◽  
Cracked Structures

The technique of strengthening structures with prestressing CFRP can improve the load-carrying behavior of reinforced concrete structures and has gained more and more attention recent years. However the research about behavior of the pre-cracked structures after retrofit is rather limited. In this paper two RC beams with large dimension were constructed. One beam was strengthened by non-prestressed CFRP plate serving as reference beam. And the other beam had been loaded to its yielding load before it was strengthened with a prestressed CFRP plate. The monotonic tests were conducted to investigate the effect of strengthening with prestressed CFRP on the behavior of the pre-damaged beam. Based on the experiment results, the comparison of behavior between the beam with non-prestressed CFRP plate and the pre-cracked beam with prestressed CFRP was conducted. The experiment results indicated that although having been loaded to its steel yielding before being strengthened, the specimen with prestressed CFRP plate had a load-carrying capacity no less than the intact beam with non-prestressed CFRP plate. Despite the serious damages of section, the stiffness of the pre-cracked specimen was almost equal to that of the reference specimen, which indicates that the technique of strengthening structures with prestressed CFRP plates can be effective in the retrofit of the seriously cracked reinforced concrete structures.

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.

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.

Time-dependent safety performance of reinforced concrete structures

2020 ◽  
Vol 18 (5) ◽  
pp. 1103-1120
Author(s):  
Utino Worabo Woju ◽  
A.S. Balu
Keyword(s):  
Reinforced Concrete ◽  
Environmental Factors ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Time Dependent ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Content Type ◽  
Creep And Shrinkage

Purpose Performance of the structure depends on design, construction, environment, utilization and reliability aspects. Other factors can be controlled by adopting proper design and construction techniques, but the environmental factors are difficult to control. Hence, mostly in practice, the environmental factors are not considered in the analysis and design appropriately; however, their impact on the performance of the structures is significant along with the design life. It is in this light that this paper aims to perform the time-dependent performance analysis of reinforced concrete structures majorly considering environmental factors. Design/methodology/approach To achieve the intended objective, a simply supported reinforced concrete beam was designed and detailed as per the Euro Code (EC2). The time-dependent design parameters, corrosion parameters, creep and shrinkage were identified through thorough literature review. The common empirical equations were modified to consider the identified parameters, and finally, the time-dependent performance of reinforced concrete beam was performed. Findings Findings indicate that attention has to be paid to appropriate consideration of the environmental effect on reinforced concrete structures. In that, the time-dependent performance of reinforced concrete beam significantly decreases with time due to corrosion of reinforcement steel, creep and shrinkage. Originality/value However, the Euro code, Ethiopian code and Indian code threat the exposure condition of reinforced concrete by providing corresponding concrete cover that retards the corrosion initiation time but does not eliminate environmental effects. The results of this study clearly indicate that the capacity of reinforced concrete structure degrades with time due to corrosion and creep, whereas the action on the structure due to shrinkage increases. Therefore, appropriate remedial measures have to be taken to control the defects of structures due to the environmental factors to overcome the early failure of the structure.

scholarly journals Geodetic monitoring of deflections of reinforced beams and reinforcing elements under variable static loading

2020 ◽  
Vol 164 ◽  
pp. 08026
Author(s):  
Igor Rubtsov ◽  
Oleg Rubtsov
Keyword(s):  
Reinforced Concrete ◽  
Strain Gauge ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Research Systems ◽  
Reinforced Beams ◽  
Concrete Elements

In the framework of the present study was carried out monitoring of reinforced concrete structures subjected to reinforcement. As reinforcement elements, steel channels were used, rigidly connected to a reinforced concrete beam to be reinforced. Object of research: systems of quasi-continuous observations of the parameters of the construction object carried out on the basis of the monitoring system. Subject of research: identification of the possibility of using various systems, in particular, geodetic and strain gauge monitoring, to monitor the bending of reinforced concrete elements and, in particular, reinforced concrete beams. Aim: Comparative analysis of strain gauge and geodetic monitoring in the process of fixed changes in static loads on structural elements. Materials and methods: the initial materials for this study were the results of geodesic and strain gauge monitoring during statistical step-by-step loading of reinforced concrete beam by steel channels. Results: on the basis of the obtained dependences of the deflection of elements of reinforced and reinforcing structures in time during their step-by-step statistical loading the possibility of using geodetic control is shown. Conclusions: The possibility of using geodesic and strain gauge methods for monitoring reinforced concrete structures is proved.

scholarly journals Estimation of cracking of reinforced concrete load-bearing construction structures at the stage of their technical inspection

2018 ◽  
Vol 251 ◽  
pp. 02040
Author(s):  
Anna Malakhova
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Technical Condition ◽  
Complex Nature ◽  
Reinforced Concrete Structures ◽  
Structural Elements ◽  
Fracture Formation ◽  
The Relationship

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.

scholarly journals Application of concrete deformation model for calculation of bearing capacity of reinforced concrete structures

2018 ◽  
Vol 196 ◽  
pp. 04008
Author(s):  
Vasiliy Murashkin ◽  
Gennadiy Murashkin
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Functional Dependencies ◽  
Proposed Model ◽  
Concrete Elements

The paper presents a brief historical reference of the theory of reinforced concrete structures calculation and its. It shows that modeling of concrete deformations makes it possible not only to carry out calculations of durability and to determine reinforced concrete elements deflection under the estimated load, but also to analyze their a stress-strain state at each stage. The study suggests a new model of concrete deformation which makes it possible to make calculations of concrete elements with characteristics which are different from those given in specification documents. The researchers use the proposed model of deformation and calculate curved reinforced concrete beam bearing capacity. These calculations for normally reinforced elements do not considerably differ from the calculations given in the documents. All the main functional dependencies on the calculation stages are visualized.

scholarly journals TECHNOLOGY OF COMPUTATION OF REINFORCED CONCRETE STRUCTURES/GELŽBETONINŲ KONSTRUKCIJŲ ARMATŪROS AUTOMATIZUOTO SKAIČIAVIMO TECHNOLOGIJA

2001 ◽  
Vol 7 (6) ◽  
pp. 419-424
Author(s):  
Arvydas Jurkša
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
New Technology ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Finite Element Program ◽  
Code Of Practice ◽  
Element Program

The author has created a new technology for concrete beam, column, slab, wall and shell reinforcement computation according to the finite element program COSMOS/M analysis results and code of practice valid in Lithuania. A brief description of the technology is included in the article. Computer programmes COSARM and COSMAX were designed for slab, wall and shell reinforcement computation. Results can be visualized graphically. New computer programmes BEAM, COSBEAM, COLUMN, COSREC and COSCIR were created for beam and column reinforcement computation. The new technology extremely enlarged the possibilities of the powerful finite element program COSMOS/M and enabled to compute very complicated reinforced concrete structures.

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