Deflection of superelastic shape memory alloy reinforced concrete beams: assessment of existing models

2010 ◽  
Vol 37 (6) ◽  
pp. 842-854 ◽  
Author(s):  
Y. I. Elbahy ◽  
M. A. Youssef ◽  
M. Nehdi
Keyword(s):  
Reinforced Concrete ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Cross Section ◽  
Parametric Study ◽  
Companion Paper ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Deflection Analysis ◽  
The Moment

This paper investigates the load–deflection behaviour of shape memory alloy (SMA) reinforced concrete (RC) beams through a parametric study. The effects of the cross-section height, cross-section width, reinforcement ratio, reinforcement modulus of elasticity, and concrete compressive strength were considered. The sectional analysis methodology was adopted to predict the moment–curvature relationship for the considered sections. Deflection was then estimated using the moment–area method. The applicability of this method for SMA RC beams was demonstrated through comparisons with available experimental results. Based on the results of the parametric study, an assessment of the available models for deflection analysis of SMA RC beams was conducted. The accuracy and reliability of the different models were evaluated, and suitable models were recommended. A companion paper provides the development of an artificial intelligence based model that can predict the deflection of SMA RC beams more accurately than existing models.

Artificial neural network model for deflection analysis of superelastic shape memory alloy reinforced concrete beams

2010 ◽  
Vol 37 (6) ◽  
pp. 855-865 ◽  
Author(s):  
Y. I. Elbahy ◽  
M. Nehdi ◽  
M. A. Youssef
Keyword(s):  
Reinforced Concrete ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Companion Paper ◽  
Reduction Factor ◽  
Moment Of Inertia ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Design Chart ◽  
Artificial Neural

The need for a new model capable of accurately predicting the deflection of shape memory alloy (SMA) reinforced concrete (RC) beams is clear from the results obtained in the companion paper. In the present paper, artificial neural networks (ANNs) are utilized to develop such a model. The objective is to create a design tool for computing a reduction factor β to be used in the calculation of the effective moment of inertia for SMA RC beams. First, a database was developed using the results obtained from the parametric study reported in the companion paper. The main factors affecting the moment of inertia have been considered. The network architecture that results in the optimum performance was selected and trained. After demonstrating the network’s ability to predict output data for unfamiliar input data, the network was used to develop a design chart that provides the reduction factor β as a function of the reinforcement ratio and the reinforcement modulus of elasticity. A design example is discussed to illustrate the advantages of using the developed design chart over existing models.

scholarly journals Strengthening of Reinforced Concrete Beams with Externally Mounted Sequentially Activated Iron-Based Shape Memory Alloys

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 345 ◽  
Author(s):  
Emanuel Strieder ◽  
Christoph Aigner ◽  
Gabriele Petautschnig ◽  
Sebastian Horn ◽  
Marco Marcon ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Reference Beam ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Recovery Stress ◽  
Strengthened Beam ◽  
Iron Based ◽  
Stress States

Iron based shape memory alloys (Fe-SMA) have recently been used as active flexural strengthening material for reinforced concrete (RC) beams. Fe-SMAs are characterized by a shape memory effect (SME) which allows the recovery of previously induced plastic deformations through heating. If these deformations are restrained a recovery stress is generated by the SME. This recovery stress can be used to prestress a SMA applied as a strengthening material. This paper investigates the performance and the load deformation behavior of RC beams strengthened with mechanical end anchored unbonded Fe-SMA strips activated by sequentially infrared heating. The performance of a single loop loaded and a double loop loaded SMA strengthened RC beam are compared to an un-strengthened beam and a reference beam strengthened with commercially available structural steel. In these tests the SMA strengthened beam had the highest cracking load and the highest ultimate load. It is shown that the serviceability behavior of a concrete beam can be improved by a second thermal activation. The sequential heating procedure causes different temperature and stress states during activation along the SMA strip that have not been researched previously. The possible effect of this different temperature and stress states on metal lattice phase transformation is modeled and discussed. Moreover the role of the martensitic transformation during the cooling process on leveling the inhomogeneity of phase state in the overheated section is pointed out.

scholarly journals BENDING WITH TORSION OF FIBER REINFORCED CONCRETE BEAM OF CIRCULAR CROSS SECTION

2021 ◽  
Vol 17 (3) ◽  
pp. 173-181
Author(s):  
Sergey Bulkin
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
High Strength Steel ◽  
Circular Cross Section ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
The Moment

The article provides information about the tests of circle cross-section reinforced concrete beams made of high-strength steel-fiberconcrete on combined torsion and bending. Given information contains the main results: a diagram of the cracks with an indication of their opening width, the values of support reactions at the moment of cracking and at the moment before destruction. It was found that as the load is applied in beams made of high-strength steel-reinforced concrete, in the case of several cracks at the firststage, there is one crack increases. The beams are modeled in the design complex and given description of the main design parameters. The results of the calculation are presented and a comparative analysis of the results obtained with the experiments results. It is noted that the adopted models in the computational complexes require the development of subroutines and refinement

Behavior and modeling of superelastic shape memory alloy reinforced concrete beams

2013 ◽  
Vol 49 ◽  
pp. 893-904 ◽  
Author(s):  
Alaa Abdulridha ◽  
Dan Palermo ◽  
Simon Foo ◽  
Frank J. Vecchio
Keyword(s):  
Reinforced Concrete ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Concrete Beams ◽  
Reinforced Concrete Beams

scholarly journals Reliability analysis of the existing reinforced concrete beams with normal cracks by rebar strength criteria

2020 ◽  
Vol 220 ◽  
pp. 01043
Author(s):  
Sergey A. Solovyev ◽  
Anastasia A. Solovyeva ◽  
Alexander A. Kochkin ◽  
Timur R. Akhmetov
Keyword(s):  
Reinforced Concrete ◽  
Reliability Analysis ◽  
Cross Section ◽  
Modulus Of Elasticity ◽  
Crack Width ◽  
Concrete Beams ◽  
Functional Dependence ◽  
Strength Criterion ◽  
Reinforced Concrete Beams ◽  
Rc Beams

The paper describes the problem of the reliability analysis for individual reinforced concrete (RC) beams by the rebar strength criterion in cross section with a normal crack. It is proposed to evaluate the stress in the rebar by measurements of the crack width at the level of the rebar using the functional dependence of the crack width and the strain (deformation) in the reinforcement. It is also proposed to replace the modulus of elasticity of steel reinforcement on the secant modulus of elasticity, taking into account the increased reinforcement strain in cross section with crack. The work considers two options of the crack width in beam: less and greater than the ultimate crack width. The reliability analysis of RC beams by the rebar strength is based on the possibility theory and fuzzy set theory by the reason of small statistical data from measurements on existing individual RC beams. The use of offered reliability analysis methods will allow preventing the failures of reinforced concrete beams and in some cases to obtain economic benefit from the possibility of further operation of RC beams with cracks, even with a crack width more than ultimate value.

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