Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
<?xml version="1.0" encoding="UTF-8" ?>
<record schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">
<leader>nam a 5i 4500</leader>
<datafield ind1="1" ind2="0" tag="245">
<subfield code="a">Active shear strengthening of reinforced concrete beams using Ni-Ti-Nb shape memory alloys</subfield>
</datafield>
<datafield ind1=" " ind2="1" tag="264">
<subfield code="a">:</subfield>
<subfield code="b">Universitat de les Illes Balears,</subfield>
<subfield code="c">2019</subfield>
</datafield>
<datafield ind1="4" ind2="0" tag="856">
<subfield code="z">Accés lliure</subfield>
<subfield code="u">http://hdl.handle.net/10803/666827</subfield>
</datafield>
<controlfield tag="007">cr |||||||||||</controlfield>
<controlfield tag="008">AAMMDDs2019 sp ||||fsm||||0|| 0 eng|c</controlfield>
<datafield ind1="1" ind2=" " tag="100">
<subfield code="a">Rius Gibert, Joan Maria,</subfield>
<subfield code="e">autor</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="300">
<subfield code="a">1 recurs en línia (284 pàgines)</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="502">
<subfield code="g">Tesi</subfield>
<subfield code="b">Doctorat</subfield>
<subfield code="c">Universitat de les Illes Balears. Departament de Física</subfield>
<subfield code="d">2019</subfield>
</datafield>
<datafield ind1="2" ind2=" " tag="710">
<subfield code="a">Universitat de les Illes Balears. Departament de Física</subfield>
</datafield>
<datafield ind1=" " ind2="4" tag="655">
<subfield code="a">Tesis i dissertacions electròniques</subfield>
</datafield>
<datafield ind1="1" ind2=" " tag="700">
<subfield code="a">Cladera Bohigas, Antoni,</subfield>
<subfield code="e">supervisor acadèmic</subfield>
</datafield>
<datafield ind1="1" ind2=" " tag="700">
<subfield code="a">Ribas González, Carlos,</subfield>
<subfield code="e">supervisor acadèmic</subfield>
</datafield>
<datafield ind1="1" ind2=" " tag="700">
<subfield code="a">Cesari Aliberch, Eduard,</subfield>
<subfield code="e">supervisor acadèmic</subfield>
</datafield>
<datafield ind1="0" ind2=" " tag="730">
<subfield code="a">TDX</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="520">
<subfield code="a">[eng] Shear strengthening of existing structures is often required as shear failures in reinforced concrete (RC) members are associated with brittle collapses, it being essential to avoid this kind of failure. This thesis presents comprehensive research on the feasibility of using Shape Memory Alloys (SMA) to actively strengthen shear critical beams. Specifically, an SMA (Ni-Ti-Nb) with wide hysteretic behavior in terms of the range of transformation temperatures for martensite and austenite phases has been applied for active external shear strengthening of RC beams using the special property of Shape Memory Effect (SME). SME refers to the phenomenon whereby SMAs can return to a predefined shape upon heating (activation). When the deformation of a prestrained SMA is constrained upon heating, it is not possible for the SMA to recover its previous shape and, therefore, it develops recovery stresses. These recovery stresses may be used for prestressing concrete members. It should be highlighted that most of the frequently used shear strengthening technologies, e.g. strengthening with fiber reinforced polymers (FRP), are passive technologies: it is necessary for the strengthened structure to increase its deformation and reach an elevated level of damage before the strengthening material can start contributing. Alternatively, a previous unloading process of the structure to recover deformations may be needed before strengthening with passive technologies. The technology proposed in this doctoral thesis uses SME to actively confine and prestress the strengthened concrete member. In this way, the strengthening material immediately begins working upon installation and activation. A complete thermo-mechanical characterization of the Ni-Ti-Nb wires used has been carried out to assess adequacy for the shear strengthening of RC beams in the ambient temperatures range for civil engineering structures. This experimental campaign for characterization of SMA included a set of tensile tests at different temperatures and another set of recovery stress tests. It has been concluded that the Ni-Ti-Nb wires show promising performance. An experimental shear strengthening campaign comprising the performance of tests to failure on 20 small-scale concrete beams with activated external shear reinforcement was carried out. Pseudo-spirals of 3 mm diameter Ni-Ti-Nb wires, or wires with a U-shape configuration, were placed around the RC beams in order to confine them and close shear cracks (if any) at activation. The experiment results show a successful increase in shear strength and the deflection measured at failure of the retrofitted beams. The effect of the geometrical imperfections of the reinforcement has also been studied and possible pre-stressing losses due to these imperfections have been evaluated by means of a new experimental campaign. The result is that Ni-Ti-Nb wires show promising performance despite possible imperfections upon installation in small-scale elements. Finally, two different shear models —the Compression Chord Capacity Model (CCCM) and shear provisions in Eurocode 2— have been used to predict the shear strength of the tested specimens. The experiment results and predictions showed good correlation, especially for the CCCM, which also showed good correlation in terms of the observed crack patterns. Based on the previously summarized research work, we can conclude that the proposed technology for active shear strengthening of RC beams works properly.</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="998">
</datafield>
<datafield ind1=" " ind2=" " tag="040">
<subfield code="a">ES-BaCBU</subfield>
<subfield code="b">cat</subfield>
<subfield code="e">rda</subfield>
<subfield code="c">ES-BaCBU</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="336">
<subfield code="a">text</subfield>
<subfield code="b">txt</subfield>
<subfield code="2">rdacontent</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="337">
<subfield code="a">informàtic</subfield>
<subfield code="b">c</subfield>
<subfield code="2">rdamedia</subfield>
</datafield>
<datafield ind1=" " ind2=" " tag="338">
<subfield code="a">recurs en línia</subfield>
<subfield code="b">cr</subfield>
<subfield code="2">rdacarrier</subfield>
</datafield>
</record>
<?xml version="1.0" encoding="UTF-8" ?>
<mets ID=" DSpace_ITEM_10803-666827" OBJID=" hdl:10803/666827" PROFILE="DSpace METS SIP Profile 1.0" TYPE="DSpace ITEM" schemaLocation="http://www.loc.gov/METS/ http://www.loc.gov/standards/mets/mets.xsd">
<metsHdr CREATEDATE="2022-09-22T10:13:52Z">
<agent ROLE="CUSTODIAN" TYPE="ORGANIZATION">
<name>TDX</name>
</agent>
</metsHdr>
<dmdSec ID="DMD_10803_666827">
<mdWrap MDTYPE="MODS">
<xmlData schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-1.xsd">
<mods:mods schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-1.xsd">
<mods:name>
<mods:role>
<mods:roleTerm type="text">author</mods:roleTerm>
</mods:role>
<mods:namePart>Rius Gibert, Joan Maria</mods:namePart>
</mods:name>
<mods:name>
<mods:role>
<mods:roleTerm type="text">authoremail</mods:roleTerm>
</mods:role>
<mods:namePart>joan.rius@uib.cat</mods:namePart>
</mods:name>
<mods:name>
<mods:role>
<mods:roleTerm type="text">authoremailshow</mods:roleTerm>
</mods:role>
<mods:namePart>false</mods:namePart>
</mods:name>
<mods:name>
<mods:role>
<mods:roleTerm type="text">director</mods:roleTerm>
</mods:role>
<mods:namePart>Cladera Bohigas, Antoni</mods:namePart>
</mods:name>
<mods:name>
<mods:role>
<mods:roleTerm type="text">director</mods:roleTerm>
</mods:role>
<mods:namePart>Ribas González, Carlos</mods:namePart>
</mods:name>
<mods:name>
<mods:role>
<mods:roleTerm type="text">tutor</mods:roleTerm>
</mods:role>
<mods:namePart>Cesari Aliberch, Eduard</mods:namePart>
</mods:name>
<mods:extension>
<mods:dateAccessioned encoding="iso8601">2019-05-10T10:40:59Z</mods:dateAccessioned>
</mods:extension>
<mods:extension>
<mods:dateAvailable encoding="iso8601">2019-05-10T10:40:59Z</mods:dateAvailable>
</mods:extension>
<mods:originInfo>
<mods:dateIssued encoding="iso8601">2019-04-05</mods:dateIssued>
</mods:originInfo>
<mods:identifier type="uri">http://hdl.handle.net/10803/666827</mods:identifier>
<mods:abstract>[eng] Shear strengthening of existing structures is often required as shear failures in reinforced concrete (RC) members are associated with brittle collapses, it being essential to avoid this kind of failure. This thesis presents comprehensive research on the feasibility of using Shape Memory Alloys (SMA) to actively strengthen shear critical beams. Specifically, an SMA (Ni-Ti-Nb) with wide hysteretic behavior in terms of the range of transformation temperatures for martensite and austenite phases has been applied for active external shear strengthening of RC beams using the special property of Shape Memory Effect (SME). SME refers to the phenomenon whereby SMAs can return to a predefined shape upon heating (activation). When the deformation of a prestrained SMA is constrained upon heating, it is not possible for the SMA to recover its previous shape and, therefore, it develops recovery stresses. These recovery stresses may be used for prestressing concrete members. It should be highlighted that most of the frequently used shear strengthening technologies, e.g. strengthening with fiber reinforced polymers (FRP), are passive technologies: it is necessary for the strengthened structure to increase its deformation and reach an elevated level of damage before the strengthening material can start contributing. Alternatively, a previous unloading process of the structure to recover deformations may be needed before strengthening with passive technologies. The technology proposed in this doctoral thesis uses SME to actively confine and prestress the strengthened concrete member. In this way, the strengthening material immediately begins working upon installation and activation. A complete thermo-mechanical characterization of the Ni-Ti-Nb wires used has been carried out to assess adequacy for the shear strengthening of RC beams in the ambient temperatures range for civil engineering structures. This experimental campaign for characterization of SMA included a set of tensile tests at different temperatures and another set of recovery stress tests. It has been concluded that the Ni-Ti-Nb wires show promising performance. An experimental shear strengthening campaign comprising the performance of tests to failure on 20 small-scale concrete beams with activated external shear reinforcement was carried out. Pseudo-spirals of 3 mm diameter Ni-Ti-Nb wires, or wires with a U-shape configuration, were placed around the RC beams in order to confine them and close shear cracks (if any) at activation. The experiment results show a successful increase in shear strength and the deflection measured at failure of the retrofitted beams. The effect of the geometrical imperfections of the reinforcement has also been studied and possible pre-stressing losses due to these imperfections have been evaluated by means of a new experimental campaign. The result is that Ni-Ti-Nb wires show promising performance despite possible imperfections upon installation in small-scale elements. Finally, two different shear models —the Compression Chord Capacity Model (CCCM) and shear provisions in Eurocode 2— have been used to predict the shear strength of the tested specimens. The experiment results and predictions showed good correlation, especially for the CCCM, which also showed good correlation in terms of the observed crack patterns. Based on the previously summarized research work, we can conclude that the proposed technology for active shear strengthening of RC beams works properly.</mods:abstract>
<mods:language>
<mods:languageTerm authority="rfc3066">eng</mods:languageTerm>
</mods:language>
<mods:titleInfo>
<mods:title>Active shear strengthening of reinforced concrete beams using Ni-Ti-Nb shape memory alloys</mods:title>
</mods:titleInfo>
<mods:genre>info:eu-repo/semantics/doctoralThesis</mods:genre>
</mods:mods>
</xmlData>
</mdWrap>
</dmdSec>
<amdSec ID="FO_10803_666827_1">
<techMD ID="TECH_O_10803_666827_1">
<mdWrap MDTYPE="PREMIS">
<xmlData schemaLocation="http://www.loc.gov/standards/premis http://www.loc.gov/standards/premis/PREMIS-v1-0.xsd">
<premis:premis>
<premis:object>
<premis:objectIdentifier>
<premis:objectIdentifierType>URL</premis:objectIdentifierType>
<premis:objectIdentifierValue>http://www.tdx.cat/bitstream/10803/666827/1/tjmrg1de1.pdf</premis:objectIdentifierValue>
</premis:objectIdentifier>
<premis:objectCategory>File</premis:objectCategory>
<premis:objectCharacteristics>
<premis:fixity>
<premis:messageDigestAlgorithm>MD5</premis:messageDigestAlgorithm>
<premis:messageDigest>f3225a32f208b74255088b1ed5d58e62</premis:messageDigest>
</premis:fixity>
<premis:size>13831851</premis:size>
<premis:format>
<premis:formatDesignation>
<premis:formatName>application/pdf</premis:formatName>
</premis:formatDesignation>
</premis:format>
</premis:objectCharacteristics>
<premis:originalName>tjmrg1de1.pdf</premis:originalName>
</premis:object>
</premis:premis>
</xmlData>
</mdWrap>
</techMD>
</amdSec>
<fileSec>
<fileGrp USE="ORIGINAL">
<file ADMID="FO_10803_666827_1" CHECKSUM="f3225a32f208b74255088b1ed5d58e62" CHECKSUMTYPE="MD5" GROUPID="GROUP_BITSTREAM_10803_666827_1" ID="BITSTREAM_ORIGINAL_10803_666827_1" MIMETYPE="application/pdf" SEQ="1" SIZE="13831851">
</file>
</fileGrp>
</fileSec>
<structMap LABEL="DSpace Object" TYPE="LOGICAL">
<div ADMID="DMD_10803_666827" TYPE="DSpace Object Contents">
<div TYPE="DSpace BITSTREAM">
</div>
</div>
</structMap>
</mets>
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
<?xml version="1.0" encoding="UTF-8" ?>
<atom:entry schemaLocation="http://www.w3.org/2005/Atom http://www.kbcafe.com/rss/atom.xsd.xml">
<atom:id>http://hdl.handle.net/10803/666827/ore.xml</atom:id>
<atom:published>2019-05-10T10:40:59Z</atom:published>
<atom:updated>2019-05-10T10:40:59Z</atom:updated>
<atom:source>
<atom:generator>TDX</atom:generator>
</atom:source>
<atom:title>Active shear strengthening of reinforced concrete beams using Ni-Ti-Nb shape memory alloys</atom:title>
<atom:author>
<atom:name>Rius Gibert, Joan Maria</atom:name>
</atom:author>
<oreatom:triples>
<rdf:Description about="http://hdl.handle.net/10803/666827/ore.xml#atom">
<dcterms:modified>2019-05-10T10:40:59Z</dcterms:modified>
</rdf:Description>
<rdf:Description about="http://www.tdx.cat/bitstream/10803/666827/2/tjmrg1de1.pdf.xml">
<dcterms:description>MEDIA_DOCUMENT</dcterms:description>
</rdf:Description>
<rdf:Description about="http://www.tdx.cat/bitstream/10803/666827/1/tjmrg1de1.pdf">
<dcterms:description>ORIGINAL</dcterms:description>
</rdf:Description>
</oreatom:triples>
</atom:entry>
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.
Se ha omitido la presentación del registro por ser demasiado largo. Si lo desea, puede descargárselo en el enlace anterior.