Effects of Aggregate Size on Concrete Shear Strength

2014 ◽  
Vol 970 ◽  
pp. 143-146
Author(s):  
Lau Teck Leong ◽  
Chen Zhe ◽  
Abdullahi Ali Mohamed ◽  
Wee Kang Choong
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Aggregate Size ◽  
Shear Behaviour ◽  
Maximum Aggregate Size ◽  
Small Scale ◽  
Reinforced Concrete Structures ◽  
Normal Concrete

In view of the importance of the applicability of small-scale beam specimens in replicating the shear behaviour of prototype reinforced concrete structures, this study was conducted on beam specimens cast with micro-concrete having scaled aggregates (maximum sizes: 10mm, 5mm, and 2mm) to investigate whether the use of micro-concrete impose any reduction in their shear strength. The results indicate the maximum aggregate size (s) has negligible effects on concrete shear strength, and the micro-concrete beam specimens replicate the shear behaviour of normal concrete.

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.

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.

Small Scale Models for Reinforced Concrete Structures

1977 ◽  
Vol 20 (1) ◽  
pp. 0132-0137
Author(s):  
A. H. Chowdhury ◽  
R. N. White ◽  
N. R. Scott
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Small Scale ◽  
Reinforced Concrete Structures ◽  
Scale Models

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 Development of Bonded/Riveted Steel Anchorages of Prestressed CFRP Strips for Concrete Strengthening

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2217
Author(s):  
Bartosz Piątek ◽  
Tomasz Siwowski ◽  
Jerzy Michałowski ◽  
Stanisław Błażewicz
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Concrete Surface ◽  
Epoxy Adhesive ◽  
Full Scale ◽  
Steel Plates ◽  
Tensile Failure ◽  
Small Scale ◽  
Reinforced Concrete Structures ◽  
Flexural Strengthening

CFRP (carbon fiber reinforced polymer) strips are currently often used to strengthen reinforced concrete structures in flexure. In order to ensure effective strengthening, proper connection between FRP material and concrete structure is needed. CFRP strips can be applied passively (only by bonding to the concrete surface) or actively (by prestressing before bonding). In the case of passive strengthening, CFRP strips connecting by bonding to the surface along the strengthened element are usually sufficient. However, active (prestressing) CFRP strips should be additionally anchored at their ends. Anchoring of unidirectional CFRP strips to the reinforced concrete is difficult because of their weak properties in transverse directions. The paper presents a development of mechanical steel anchorages used in an active CFRP flexural strengthening system for reinforced concrete structures. The anchorages were made of steel plates connected to CFRP strips with steel rivets and epoxy adhesive. They were developed within series of tests on specimens from small-scale to full-scale tested in an axial tensile scheme. The paper describes successive modifications of the anchorages as well as the results of full-scale tests. The final version of the anchorage developed during the research had a tensile failure force of 185 kN, which is sufficient value for CFRP strengthening purposes.

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.

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.

An adequate theory for the shear strength of reinforced concrete structures

2008 ◽  
Vol 60 (9) ◽  
pp. 635-650 ◽  
Author(s):  
M. P. Collins ◽  
E. C. Bentz ◽  
E. G. Sherwood ◽  
L. Xie
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Adequate Theory
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