The Experimental Study on Fatigue Properties of CFRP Reinforced Concrete Beam

2011 ◽  
Vol 383-390 ◽  
pp. 3157-3161
Author(s):  
Zi Qi Li ◽  
Yan Yan Fan
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Experimental Basis

Based on the research of CFRP reinforced concrete beam , this article indicates that CFRP can improve greatly the fatigue performance of damage concrete beam, prolong its service life , and provide the experimental basis for long-term fatigue properties of CFRP concrete structures.

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.

Experimental study of a novel precast prestressed reinforced concrete beam-to-column joint

2018 ◽  
Vol 156 ◽  
pp. 68-81 ◽  
Author(s):  
Haishen Wang ◽  
Edoardo M. Marino ◽  
Peng Pan ◽  
Hang Liu ◽  
Xin Nie
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Column Joint

scholarly journals Effect of Stirrup Spacing and Polypropylene Fiber Ratio on Behavior of Reinforced Concrete Beams

2021 ◽  
Author(s):  
Alptuğ Ünal ◽  
Salih Cengiz ◽  
Mehmet Kamanlı
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Polypropylene Fiber ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Beam Depth ◽  
Bending Capacity ◽  
Bending Mechanism

In this study, the effect of the change of stirrup ratio and polypropylene (PP) fiber ratio on the behavior of reinforced concrete beams was investigated. The variables of this study consisting of without stirrup, spacing up to 20 %, 40 % and 80 % of beam depth as stirrup spacing and 0.125 % and 0.500 % of the weight of reinforced concrete beam were used as PP fiber ratios. In the context of experimental study, 1/2 scaled 12 reinforced concrete beams were tested with 4-point bending mechanism. In the light of the obtained data, the load-displacement, stiffness and energy absorption graphs were plotted. The results were interpreted comparatively. According to the results, it is observed that the PP fiber additive significantly changed the behavior of the reinforced concrete beams, and the fiber effect decreased in proportion to the increase of the stirrup rate. It has been observed that the cracks spread more to the beam surfaces with the increase of PP fibers. In addition, the increase in the fiber ratio especially in the non-stirrup beams increases the bending capacity.

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.

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