Weimar in germany, a concrete beam was reinforced with shape memory alloys sma wires czaderski et al. Strengtheningreinforcing concrete structures using shape. Retrofitting using shape memory alloys sma shape memory alloys have been gaining a great amount of attention in civil infrastructure researches where it is seen to have a huge future in retrofitting of structure. Smart structures with pseudoelastic and pseudoplastic shape. Hybrid confinement of high strength concrete using shape memory alloys and fiberreinforced polymers pratik sharad deogekar and bassem andrawes department of civil and environmental engineering, university of illinois at urbanachampaign, urbana, il, usa. He published over 220 journal and conference papers, coauthored 3 refereed design guidelines. Selfcentering of shape memory alloy fiber reinforced. Pdf seismic performance of concrete frames reinforced. Since steel reinforcement cannot regain its shape beyond yielding, the performance deteriorates enormously when subjected to a strong cyclic load. Shear failures in rc members are associated with brittle collapses, for this reason, shear strengthening of existing structures is often required.
Civil engineering department, national institute of technology, durgapur, india abstract. In particular, a quantitative micromechanical procedure to obtain the effective thermomechanical properties and the behavior of prestressed concrete reinforced by shape memory alloy. Pdf flexural behaviour of concrete members reinforced. Shape memory alloys smas are a unique class of materials which have ability to. Youssef department of civil and environmental engineering, the university of western ontario london, ontario, n6a 5b9, canada received march 25, 2008, accepted june 29, 2009 abstract. Superelastic shape memory alloys smas are a class of metallic alloys that have the unique property of being able to undergo large amounts of plastic strain while remaining elastic and dissipating. Flexural behaviour of concrete members reinforced with shape memory alloys conference paper pdf available january 2008 with 81 reads how we measure reads. Probabilistic seismic risk assessment of concrete bridge. Shape memory alloy sma, with its distinct superelasticity, shape memory effect and hysteretic damping, is a promising material for the application in bridge piers to attain the objectives of pbsd. Utilizing shape memory alloys to enhance the performance and safety of civil infrastructure.
Seismic performance of concrete bridge piers reinforced with. Composites composed of sma wires and conventional cements can overcome the mechanical weaknesses associated with tensile fractures in conventional concretes. Flexural strengthening of structural concrete with iron. The use of sma for the retrofitting of rc walls is. The experiment has three stages including loading, unloading and heating the sma strands. A thermomechanically micromechanical modeling of prestressed. Modeling of a reinforced concrete beam using shape memory. Request pdf rehabilitation of reinforced concrete structures using shape memory alloys the nearsurfacemounted nsm strengthening method is a. Strengthening of reinforced concrete beams with externally. Analytical prediction of the seismic behaviour of superelastic shape memory alloy reinforced concrete elements. In this report, the superelastic behavior of shape memory alloys, in particular nitinol, was used in doing preliminary tests to observe the extent of the ability of this alloy to confine concrete, decrease and minimize residual crack sizes in concrete, and to recover. Potential applications of shape memory alloys in seismic retrofitting of an exterior reinforced concrete beamcolumn joint raj suhail1, giuseppina amato2, jianfei chen3 and daniel mccrum4 abstract shape memory alloys smas have the ability to. To deal with the problems of the integrity of the reinforced concrete structure, research on smart material such as shape memory alloy sma is essential to. The seismic behaviour of concrete frames reinforced with smas is being assessed.
The rehabilitation properties of intelligent concrete beam reinforced with shape memory alloys sma is investigated. The most common form of sma wires used for concrete confinement applications is nickle titanium niti because it possesses unique thermomechanical properties such as the shape memory effect sme along with high recovery stress up to 600 mpa and strain. Pdf the use of shape memory alloys as a rebar in concrete structures has been receiving increasing attention among researchers. Development of innovative selfcentering concrete beam. The recentering phenomenon of superelastic shape memory alloy sma reinforced concrete is a unique characteristic that is appealing for structural applications, along with the ability to respond with stable hystereses and achieve similar strength and ductility to concrete reinforced with conventional deformed bars. This behavior is obtained for di erent shapes and volume fractions of the sma bers. Performancebased damage states of shape memory alloy sma. The objective of this study is to determine the effect of parameter for performance damage states of concrete wall pier reinforced with shape memory alloy sma. This paper studies the seismic performance of braced and unbraced concrete frames reinforced with superelastic shape memory alloys smas. Shape memory alloys smas are increasingly becoming a topic of research in the. Seismic performance of concrete frame structures reinforced with superelastic shape memory alloys.
In an attempt to reduce permanent displacement and damage, a hybrid reinforced concrete rc bridge pier configuration is considered in the present study. Tensile and impact behaviour of shape memory alloy fibre. Sma strip is prestrained at ambient temperature with a remaining deformation. As a smart material, the study of shape memory alloy in civil engineering mainly in the selfmonitoring and selfrepairing of concrete beams, earthquake resistance and reinforcement of concrete columns, seismic damping of concrete structures, etc. Probabilistic seismic risk assessment of concrete bridge piers reinforced with di. Applications of shape memory alloys in structural engineering. The development of shape memory alloy and its main features are outlined. The main objective of this research study is to design innovative selfcentering concrete beamcolumn connections reinforced using shape memory alloy sma bars with relocated plastic hinges. Lead free proof of concept solder matrix alloys of snbi with off eutectic compositions were designed, synthesized and characterized.
Prestressing concrete with shape memory alloy fibers skye mikaella orvis concrete is considerably stronger in compression than it is in tension. Superelastic shape memory alloy cables for reinforced concrete. Reinforced concrete rc framed buildings dissipate the seismic energy through yielding of the reinforcing bars. Analysis of instantaneous and timedependent deflections in shape memory alloy reinforced concrete flexural members s. The use of shape memory alloys smas has increasingly expanded in recent decades. The plastic hinge region of the bridge pier is reinforced with superelastic shape memory alloy sma and the remaining portion with regular steel. The demonstrator is 62% lighter than an equivalent domeshaped steel fender skirt. When cracks form in concrete members, the flexural stiffness of the member decreases and the deflection increases which increases the overall size of the member. Subsequently, it is applied on the structure as an end. Hybrid confinement of high strength concrete using shape memory alloys and fiberreinforced polymers. As an alternative to steel reinforcement, shape memory alloy smabased reinforcing bars are emerging for improving the seismic performance of concrete bridge piers.
Sep 20, 2018 pre1970s designed and built reinforced concrete frame structures are considered unsafe when subjected to seismic loads. Applications of shape memory alloys smas in civil engineering are expanding more and more because of the unique properties of these alloys such as the shape memory effect and superelastic behavior. In this study, the seismic performance of a newly proposed seismicforceresisting system, consisting of superelastic shape memory alloy sma reinforced concrete building, was evaluated. Confining jackets for concrete cylinders using nitinb and. Newly built frame structures are seismically designed for safety, where high inelastic deformations can occur under moderate to strong earthquakes. Youssef2 abstract superelastic shape memory alloys smas are unique materials which can regain their original length upon unloading. Shape memory alloy reinforced selfhealing metal matrix. Schematic of intelligent reinforced concrete specimen. Ironbased shape memory alloys fesma a new material. Smas have the ability to regain their original shape after being deformed up to 68% strain. Current and past research has been based on yielding steel reinforcement in order to dissipate the earthquake energy. In particular, the alloys are used for concrete or reinforced concrete to improve their performances. Shahria alam school of engineering, the university of british columbia, kelowna, bc v1v1v7, canada article info keywords. Rehabilitation of reinforced concrete structures using shape.
Fesmas are characterized by a shape memory effect sme which allows the recovery of previously induced plastic deformations through heating. This paper presents an innovative system for retrofitting shear critical reinforced concrete rc beams, taking advantage of the shape memory effect of shape memory alloys smas. This paper presents an assessment of concrete bridge piers with different reinforcement alternatives, namely steel reinforcement, steelsma hybrid reinforcement and sma reinforcement. In addition to ductility of the reinforced concrete, it is desirable to have large recoverable deformations selfcentering ability under strong cyclic loading conditions.
Hybrid confinement of high strength concrete using shape memory alloys and fiber reinforced polymers pratik sharad deogekar and bassem andrawes department of civil and environmental engineering, university of illinois at urbanachampaign, urbana, il, usa abstract. Keywords shape memory alloy, prestressed, laminated composite, automotive, morphing, fender skirt, drag reduction. Active confinement of reinforced concrete bridge columns. In this study, sma strands, made of 7 single wires, are used to replace the. It was found that each smart material had potential to improve the performance of reinforced concrete structures. Applications of shape memory alloys in civil structures.
Shear strengthening of reinforced concrete beams using. Pdf seismic performance of concrete frame structures. Jun 06, 2010 this paper investigates the loaddeflection behaviour of shape memory alloy sma reinforced concrete rc beams through a parametric study. Recently, shape memory alloys smas have received considerable attention as a class of smart materials that can be employed in bridge engineering applications. Incremental dynamic analyses of concrete buildings reinforced with shape memory alloy article pdf available january 2017 with 152 reads how we measure reads. Selfcentering of shape memory alloy fiber reinforced cement. A primary characteristic of shape memory alloys sma is pseudoelasticity. This yielding jeopardizes the serviceability of these buildings as it results in residual lateral deformations. The recentering phenomenon of superelastic shape memory alloy sma reinforced concrete is a unique characteristic that is appealing for structural applications, along with the ability to respond with stable hystereses and achieve similar strength and ductility to concrete reinforced with. Seismic performance of concrete bridge piers reinforced. Mehdi ghassemieh1, moein rezapour1 and vahid sadeghi2.
Utilizing superelastic sma bars in reinforced concrete rc frames results in dissipating the earthquake energy. The objective of this research is to develop a performancebased seismic design guideline for concrete bridge pier reinforced with different types. Experimental investigation on the seismic behavior of beam. Pdf incremental dynamic analyses of concrete buildings. Stress block parameters for concrete flexural members reinforced with superelastic shape memory alloys. Seismic performance of concrete frames reinforced with superelastic shape memory alloys article pdf available in smart structures and systems 94 april 2012 with 416 reads how we measure reads. Apr 03, 2017 performancebased damage states of shape memory alloy sma reinforced concrete bridge piers. Nonlinear simulation of reinforced concrete beams retrofitted by nearsurface mounted ironbased shape memory alloys sahar abouali et ala new nearsurfacemounted anchorage system of shape memory alloys for local strengthening shengshan pan et alflexural capacity and crackclosing performance of niti and nitinb shape. Thirteen different reinforced concrete rc ductile moment. Seismic performance of concrete frame structures reinforced with superelastic shape memory alloys m. Seismic performance of concrete frame structures reinforced. Hybrid confinement of high strength concrete using shape memory alloys and fiber reinforced polymers. Rehabilitation of concrete beam by using martensitic shape.
Seismic performance of reinforced concrete frames retrofitted. It may be noted that in that study, the constitutive. This paper presents an innovative system for retrofitting shear critical reinforced concrete rc beams, taking advantage of the. Elhacha research interest focuses on using high performance advanced materials, such as frps, shape memory alloy, ultrahigh performance concrete, for hybrid structural systems in bridge applications and other structures. Analysis of instantaneous and timedependent deflections. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. This paper investigates the loaddeflection behaviour of shape memory alloy sma reinforced concrete rc beams through a parametric study. A study of shapememoryalloyreinforced beams and cubes. Probabilistic seismic risk assessment of concrete bridge piers reinforced with different types of shape memory alloys.
Hybrid confinement of high strength concrete using shape. Jan 01, 2010 this paper presents experimental and analytical work conducted to explore the feasibility of using an innovative technique for seismic retrofitting of rc bridge columns using shape memory alloys s. Performance of eccentrically loaded reinforced concrete. An alternative reinforcement material such as shape memory alloy sma could. Shape memory alloy sma is a novel functional material and has found increasing applications in. Prestressing concrete with shape memory alloy fibers. Shape memory alloys smas are singular materials that have the ability to achieve high deformations and to return to a predefined shape after. Behavior and modeling of superelastic shape memory alloy. Superelastic shape memory alloy composite bars for. Pre1970s designed and built reinforced concrete frame structures are considered unsafe when subjected to seismic loads.
Moreover this study proposes a new method that can be used to confine reinforced concrete circular columns using sma plates. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quickrelease latches. Steng numerical analysis and wrote the manuscript which was further edited by dr. Selfhealing is an essential property of smart concrete structures. Ali, mohamed ali elsayed mahmoud, tensile and impact behaviour of shape memory alloy fibre reinforced engineered cementitious composites 2017. Deflection of superelastic shape memory alloy reinforced. Insufficient anchorage of the beam reinforcement in the beamcolumn joints of these structures is considered a main deficiency. In this study, sma strands, made of 7 single wires, are used to replace the steel bars in ordinary concrete beam. Experimental testing and constitutive modeling of concrete confined with shape memory alloys by qiwen chen dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy in civil engineering in the graduate college of the university of illinois at urbanachampaign, 2015 urbana, illinois doctoral committee. The plastic hinge region of the bridge pier is reinforced with superelastic shape memory alloy sma and the. Rehabilitation of reinforced concrete structures using. Pdf shapememory alloys possess a number of unique characteristics, such as shape memory and superelasticity.
It is proposed that with select reinforcement, the unique properties of smafrp composites can be used to add ductility and energy dissipation to concrete structures primarily reinforced with frp. Introduction shape memory alloy sma strips can be used as prestressing elements to strengthen reinforced concrete rc members. Confinement of reinforced concrete columns using shape. Shape memory alloy damage states incremental dynamic analysis residual drift. The proposed systems utilize the psuedoelastic pe response of sma in recentering the connection after being subjected to earthquakelike motion.
Experimental investigations on shape memory alloy fiber. Newly built frame structures are seismically designed for safety, where high inelastic deformations can occur under moderate to strong. The effects of the crosssection height, crosssection width, reinforcement ratio, reinforcement modulus of elasticity, and concrete compressive strength were considered. Bondslip behavior of superelastic shape memory alloys for. If these deformations are restrained a recovery stress is generated by the sme. Shear strengthening of reinforced concrete beams using shape. The recentering phenomenon of superelastic shape memory alloy sma reinforced concrete is a unique characteristic that is appealing for structural. A metal matrix composite system incorporating nickel titanium niti shape memory alloy sma as smart reinforcement with selfhealing potential for crack closure is investigated.
In contrast to other structural metals, shape memory alloys smas offer two unique effects. The test of single point loading at the midspan is conducted on the beam. Experimental investigations on shape memory alloy fiber reinforced. This paper presents a study on structural concrete retrofitting with iron. Failure modes of reinforced concrete beams explained duration. Behavior of beamcolumn joints reinforced with superelastic shape memory alloys m. Research progress of smart concrete structures reinforced. Saha2 1senior scientist, csircentral mechanical engineering research institute, durgapur, india 2prof. Abstract smart materials such as shape memory alloys sma are recently utilized for strengthening and repairing of concrete structures. Ironbased shape memory alloys fesma a new material for. The shape memory effect sme turns a material that is deformed beyond. Effectiveness of the shape memory alloy reinforcement in concrete. There are several micromechanical models that are capable to predict the macroscopic behavior of composite materials with embedded shape memory alloy bers. The loaddeflection behaviors of shape memory alloy sma.
Iron based shape memory alloys fesma have recently been used as active flexural strengthening material for reinforced concrete rc beams. Strengthening of reinforced concrete beams with externally mounted sequentially activated ironbased shape memory alloys emanuel strieder 1. This paper discusses the superelastic behavior of shape memory alloy, niti when used as reinforcement in concrete beams. Superelastic shape memory alloys smas are gaining acceptance for use as reinforcing bars in concrete structures. Collapse and severe damage of reinforced concrete structures during strong earthquakes has been a major concern for structural engineers. There are, however, a group of materials with this property. Research progress of smart concrete structures reinforced by. Pdf electricalmechanical monitoring of shape memory.
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