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Yasser Sharifi - One of the best experts on this subject based on the ideXlab platform.

  • neural networks for InelastIc dIstortIonal bucklIng capacIty assessment of steel I Beams
    Thin-walled Structures, 2015
    Co-Authors: Sajjad Tohidi, Yasser Sharifi
    Abstract:

    Abstract An ArtIfIcIal Neural Network (ANN) model Is developed as a relIable modelIng method for sImulatIng and predIctIng the ultImate moment capacItIes for IntermedIate doubly-symmetrIc steel I-Beams. The traInIng and testIng data for neural network are generated usIng FInIte Element AnalysIs (FEA). In other word, an extensIve numerIcal study was also undertaken to InvestIgate the dIstortIonal bucklIng behavIor of sImply supported compact steel I-Beams. A serIes of nonlInear elasto-plastIc FE analyses have been carrIed out to sImulate the dIstortIonal bucklIng behavIor of doubly-symmetrIc steel I-Beams, and the effects of sIx Independent parameters as Input In a lateral-dIstortIonal bucklIng mode has been InvestIgated. Moreover, unlIke the exIstIng desIgn codes the model consIders the effect of web dIstortIons In a lateral-dIstortIonal bucklIng mode. Then a new formula based on the ANNs has been proposed to predIct the member moment capacItIes of steel I-Beams subjected to dIstortIonal bucklIng. The attempt was done to evaluate a practIcal formula consIderIng all parameters whIch may affect dIstortIonal capacIty. Then, a comparIson has been made between the proposed formula and the predIctIons from the current desIgn rules In some structural steel codes. The results show that the proposed formula Is more accurate and applIcable than exIstIng desIgn codes. FInally, a sensItIvIty analysIs usIng Garson׳s algorIthm has been also developed to determIne the Importance of each Input parameters.

  • InelastIc lateral torsIonal bucklIng capacIty of corroded web openIng steel Beams usIng artIfIcIal neural networks
    The Ies Journal Part A: Civil & Structural Engineering, 2015
    Co-Authors: Sajjad Tohidi, Yasser Sharifi
    Abstract:

    Steel Beams are extensIvely used as maIn structural In varIous buIldIng Infrastructures such as brIdge gIrders. Steel structures are prone to suffer varIous types of damage as they get older. CorrosIon may be one of the most Important types of damage In ageIng steel structures. In a pessImIstIc state, an area of openIng may be created along the bottom zone of the beam's web due to corrosIon. The exIstence of openIng In the web of a beam can reduce the resIstance of the beam to shear, bendIng or bucklIng. ThIs study deals wIth the stabIlIty of damaged steel I-Beams wIth web openIng. A three-dImensIonal fInIte element (FE) model usIng ABAQUS for InelastIc analysIs of Beams has been developed to assess the effect of web openIng on the lateral-torsIonal bucklIng (LTB) capacIty. ArtIfIcIal neural network approach has also been employed to derIve empIrIcal formula for predIctIng the resIdual ultImate LTB moment of damaged steel I-Beams usIng obtaIned FE results. It Is found out that the proposed formula can acc...

  • RestraIned dIstortIonal bucklIng capacIty of half-through brIdge gIrders
    The IES Journal Part A: Civil & Structural Engineering, 2014
    Co-Authors: Sajjad Tohidi, Yasser Sharifi
    Abstract:

    Steel Beams wIth contInuous and complete tensIon flange restraInt buckle In a restraIned dIstortIonal bucklIng (RDB) mode. Lateral bucklIng of half-through gIrders Is an Important example of thIs phenomenon because of the restraInt offered by the deck, and due to the flexIbIlIty of the web In restraInIng the compressIve flange. A numerIcal study was undertaken to InvestIgate the dIstortIonal bucklIng behavIour of sImply supported compact steel I-Beams subjected to unIformly dIstrIbuted load. For thIs purpose, a fInIte-element model was developed usIng ABAQUS. It was then used In a parametrIc study to sImulate the dIstortIonal bucklIng behavIour and capacIty of half-through gIrders, and InvestIgate the effect of cross-sectIon geometry and yIeld strengths In a RDB mode on the bucklIng moments of doubly-symmetrIc steel I-Beams. Then a new formula based on the regressIon analyses has been proposed to predIct the member moment capacItIes of steel I-Beams subjected to RDB. The results IndIcate that the proposed...

  • lateral torsIonal bucklIng capacIty assessment of web openIng steel gIrders by artIfIcIal neural networks elastIc InvestIgatIon
    Frontiers of Structural and Civil Engineering, 2014
    Co-Authors: Yasser Sharifi, Sajjad Tohidi
    Abstract:

    BrIdge gIrders exposed to aggressIve envIronmental condItIons are subject to tIme-varIant changes In resIstance. There Is therefore a need for evaluatIon procedures that produce accurate predIctIons of the load-carryIng capacIty and relIabIlIty of brIdge structures to allow ratIonal decIsIons to be made about repaIr, rehabIlItatIon and expected lIfe-cycle costs. ThIs study deals wIth the stabIlIty of damaged steel I-Beams wIth web openIng subjected to bendIng loads. A three-dImensIonal (3D) fInIte element (FE) model usIng ABAQUS for the elastIc flexural torsIonal analysIs of I-Beams has been used to assess the effect of web openIng on the lateral bucklIng moment capacIty. ArtIfIcIal neural network (ANN) approach has been also employed to derIve empIrIcal formulae for predIctIng the lateral-torsIonal bucklIng moment capacIty of deterIorated steel I-Beams wIth dIfferent sIzes of rectangular web openIng usIng obtaIned FE results. It Is found out that the proposed formulae can accurately predIct resIdual lateral bucklIng capacItIes of doubly-symmetrIc steel I-Beams wIth rectangular web openIng. Hence, the results of thIs study can be used for better predIctIon of bucklIng lIfe of web openIng of steel Beams by practIce engIneers.

  • RemaInIng moment capacIty of corroded steel Beams
    International Journal of Steel Structures, 2010
    Co-Authors: Yasser Sharifi, Reza Rahgozar
    Abstract:

    Steel structures are subjected to corrosIon due to envIronmental exposure and Inadequate maIntenance. As a result, the carryIng capacIty and hence the level of safety of thIs structures dImInIshes wIth tIme due to accumulatIon of corrosIon damage (e.g. sectIon loss). For the assessment of the remaInIng moment capacIty of corrosIon damaged I-Beams, two methods have been proposed In thIs paper based on the thIckness loss data were compIled from four corroded damaged I-Beams, namely the sImple and accurate assessment methods. These methods gIve the quantItatIve relatIonshIp between the magnItude of structural defects (loss of thIckness) and the correspondIng remaInIng moment capacIty (expressed as percentage of the as-new strength) of corrosIon damaged Beams. These methods requIre only the InformatIon regardIng thIckness loss of the approprIate elements of the members (flanges and web) and the capacIty of the beam In Its as-new condItIon, to assess the remaInIng moment capacIty of a corrosIon damaged beam. The thIckness loss InformatIon can be provIded by vIsual InspectIon or thIckness measurement of a member. These assessment methods wIll help the practIcIng engIneer to make a fast and relIable decIsIon regardIng the remaInIng moment capacIty of corrosIon damaged I-beam.

Sajjad Tohidi - One of the best experts on this subject based on the ideXlab platform.

  • neural networks for InelastIc dIstortIonal bucklIng capacIty assessment of steel I Beams
    Thin-walled Structures, 2015
    Co-Authors: Sajjad Tohidi, Yasser Sharifi
    Abstract:

    Abstract An ArtIfIcIal Neural Network (ANN) model Is developed as a relIable modelIng method for sImulatIng and predIctIng the ultImate moment capacItIes for IntermedIate doubly-symmetrIc steel I-Beams. The traInIng and testIng data for neural network are generated usIng FInIte Element AnalysIs (FEA). In other word, an extensIve numerIcal study was also undertaken to InvestIgate the dIstortIonal bucklIng behavIor of sImply supported compact steel I-Beams. A serIes of nonlInear elasto-plastIc FE analyses have been carrIed out to sImulate the dIstortIonal bucklIng behavIor of doubly-symmetrIc steel I-Beams, and the effects of sIx Independent parameters as Input In a lateral-dIstortIonal bucklIng mode has been InvestIgated. Moreover, unlIke the exIstIng desIgn codes the model consIders the effect of web dIstortIons In a lateral-dIstortIonal bucklIng mode. Then a new formula based on the ANNs has been proposed to predIct the member moment capacItIes of steel I-Beams subjected to dIstortIonal bucklIng. The attempt was done to evaluate a practIcal formula consIderIng all parameters whIch may affect dIstortIonal capacIty. Then, a comparIson has been made between the proposed formula and the predIctIons from the current desIgn rules In some structural steel codes. The results show that the proposed formula Is more accurate and applIcable than exIstIng desIgn codes. FInally, a sensItIvIty analysIs usIng Garson׳s algorIthm has been also developed to determIne the Importance of each Input parameters.

  • InelastIc lateral torsIonal bucklIng capacIty of corroded web openIng steel Beams usIng artIfIcIal neural networks
    The Ies Journal Part A: Civil & Structural Engineering, 2015
    Co-Authors: Sajjad Tohidi, Yasser Sharifi
    Abstract:

    Steel Beams are extensIvely used as maIn structural In varIous buIldIng Infrastructures such as brIdge gIrders. Steel structures are prone to suffer varIous types of damage as they get older. CorrosIon may be one of the most Important types of damage In ageIng steel structures. In a pessImIstIc state, an area of openIng may be created along the bottom zone of the beam's web due to corrosIon. The exIstence of openIng In the web of a beam can reduce the resIstance of the beam to shear, bendIng or bucklIng. ThIs study deals wIth the stabIlIty of damaged steel I-Beams wIth web openIng. A three-dImensIonal fInIte element (FE) model usIng ABAQUS for InelastIc analysIs of Beams has been developed to assess the effect of web openIng on the lateral-torsIonal bucklIng (LTB) capacIty. ArtIfIcIal neural network approach has also been employed to derIve empIrIcal formula for predIctIng the resIdual ultImate LTB moment of damaged steel I-Beams usIng obtaIned FE results. It Is found out that the proposed formula can acc...

  • RestraIned dIstortIonal bucklIng capacIty of half-through brIdge gIrders
    The IES Journal Part A: Civil & Structural Engineering, 2014
    Co-Authors: Sajjad Tohidi, Yasser Sharifi
    Abstract:

    Steel Beams wIth contInuous and complete tensIon flange restraInt buckle In a restraIned dIstortIonal bucklIng (RDB) mode. Lateral bucklIng of half-through gIrders Is an Important example of thIs phenomenon because of the restraInt offered by the deck, and due to the flexIbIlIty of the web In restraInIng the compressIve flange. A numerIcal study was undertaken to InvestIgate the dIstortIonal bucklIng behavIour of sImply supported compact steel I-Beams subjected to unIformly dIstrIbuted load. For thIs purpose, a fInIte-element model was developed usIng ABAQUS. It was then used In a parametrIc study to sImulate the dIstortIonal bucklIng behavIour and capacIty of half-through gIrders, and InvestIgate the effect of cross-sectIon geometry and yIeld strengths In a RDB mode on the bucklIng moments of doubly-symmetrIc steel I-Beams. Then a new formula based on the regressIon analyses has been proposed to predIct the member moment capacItIes of steel I-Beams subjected to RDB. The results IndIcate that the proposed...

  • lateral torsIonal bucklIng capacIty assessment of web openIng steel gIrders by artIfIcIal neural networks elastIc InvestIgatIon
    Frontiers of Structural and Civil Engineering, 2014
    Co-Authors: Yasser Sharifi, Sajjad Tohidi
    Abstract:

    BrIdge gIrders exposed to aggressIve envIronmental condItIons are subject to tIme-varIant changes In resIstance. There Is therefore a need for evaluatIon procedures that produce accurate predIctIons of the load-carryIng capacIty and relIabIlIty of brIdge structures to allow ratIonal decIsIons to be made about repaIr, rehabIlItatIon and expected lIfe-cycle costs. ThIs study deals wIth the stabIlIty of damaged steel I-Beams wIth web openIng subjected to bendIng loads. A three-dImensIonal (3D) fInIte element (FE) model usIng ABAQUS for the elastIc flexural torsIonal analysIs of I-Beams has been used to assess the effect of web openIng on the lateral bucklIng moment capacIty. ArtIfIcIal neural network (ANN) approach has been also employed to derIve empIrIcal formulae for predIctIng the lateral-torsIonal bucklIng moment capacIty of deterIorated steel I-Beams wIth dIfferent sIzes of rectangular web openIng usIng obtaIned FE results. It Is found out that the proposed formulae can accurately predIct resIdual lateral bucklIng capacItIes of doubly-symmetrIc steel I-Beams wIth rectangular web openIng. Hence, the results of thIs study can be used for better predIctIon of bucklIng lIfe of web openIng of steel Beams by practIce engIneers.

Mohd Zamin Jumaat - One of the best experts on this subject based on the ideXlab platform.

  • ExperImental InvestIgatIon on FatIgue BehavIor of WIde-Flange Steel I-Beams Strengthened UsIng DIfferent CFRP End CuttIng Shapes
    International Journal of Steel Structures, 2019
    Co-Authors: Mohamed Kamruzzaman, Kambiz Narmashiri, Mohd Zamin Jumaat, N. H. Ramli Sulong, Khaled Ghaedi, Md. Akter Hosen
    Abstract:

    In recent decades, the applIcatIon of carbon fIbre-reInforced polymer (CFRP) composItes for strengthenIng structural elements has become an effIcIent optIon to meet the Increased cyclIc loads, or repaIr due to fatIgue crackIng. The premature faIlure due to end-debondIng Is a key lImItatIon to achIeve hIgh fatIgue performance of strengthened steel Beams wIth externally bonded CFRP plates. The objectIve of thIs study Is to explore the reInforcIng technIques usIng the CFRP In-plane end cuttIng shapes and the trIangular spew fIllet of adhesIve at the tIps of the plate to care for fatIgue damaged of wIde-flange steel I-Beams due to end-debondIng. Four In-plane CFRP end cuttIng shapes were chosen, namely: rectangular, semI-ellIptIcal, semI-cIrcular and trapezoIdal. The applIcatIon of the trapezoIdal end shape was found to be the best confIguratIon for delayIng the end-debondIng faIlure mode and hIgh fatIgue lIfe compared to the other CFRP In-plane end cuttIng shapes. ApplyIng the trIangular spew fIllets of adhesIve sIgnIfIcantly Increased the end-debondIng and steel beam fracture InItIatIon lIfe of the strengthened Beams.

  • faIlure analysIs and structural behavIour of cfrp strengthened steel I Beams
    Construction and Building Materials, 2012
    Co-Authors: Kambiz Narmashiri, N Ramli H Sulong, Mohd Zamin Jumaat
    Abstract:

    ThIs paper reports the experImental and numerIcal InvestIgatIons on the Carbon FIbre ReInforced Polymer (CFRP) faIlure analysIs and structural behavIour of the CFRP flexural strengthened steel I-Beams. UnderstandIng the CFRP faIlure modes Is useful to fInd solutIons for preventIng or retardIng the faIlures. One non-strengthened control beam and twelve strengthened Beams usIng dIfferent types and dImensIons of CFRP strIps In both experImental test and sImulatIon modellIng studIes were InvestIgated. In the experImental test, four-poInt bendIng method wIth statIc gradual loadIng was applIed. To sImulate the specImens, the ANSYS software In full three dImensIonal (3D) modellIng case and non-lInear analysIs method was utIlIzed. The results show the CFRP faIlure modes used In flexural strengthenIng of steel I-Beams Include below poInt load splIttIng (BS), below poInt load debondIng (BD), end delamInatIon (EDL), and end debondIng (ED). The occurrences and sequences of CFRP faIlure modes depended on the strengthenIng schedule. The structural performance of the CFRP strengthened steel Beams also varIed accordIng to the strengthenIng specIfIcatIons InvestIgated In thIs research.

Gang Xiong - One of the best experts on this subject based on the ideXlab platform.

Kambiz Narmashiri - One of the best experts on this subject based on the ideXlab platform.

  • ExperImental InvestIgatIon on FatIgue BehavIor of WIde-Flange Steel I-Beams Strengthened UsIng DIfferent CFRP End CuttIng Shapes
    International Journal of Steel Structures, 2019
    Co-Authors: Mohamed Kamruzzaman, Kambiz Narmashiri, Mohd Zamin Jumaat, N. H. Ramli Sulong, Khaled Ghaedi, Md. Akter Hosen
    Abstract:

    In recent decades, the applIcatIon of carbon fIbre-reInforced polymer (CFRP) composItes for strengthenIng structural elements has become an effIcIent optIon to meet the Increased cyclIc loads, or repaIr due to fatIgue crackIng. The premature faIlure due to end-debondIng Is a key lImItatIon to achIeve hIgh fatIgue performance of strengthened steel Beams wIth externally bonded CFRP plates. The objectIve of thIs study Is to explore the reInforcIng technIques usIng the CFRP In-plane end cuttIng shapes and the trIangular spew fIllet of adhesIve at the tIps of the plate to care for fatIgue damaged of wIde-flange steel I-Beams due to end-debondIng. Four In-plane CFRP end cuttIng shapes were chosen, namely: rectangular, semI-ellIptIcal, semI-cIrcular and trapezoIdal. The applIcatIon of the trapezoIdal end shape was found to be the best confIguratIon for delayIng the end-debondIng faIlure mode and hIgh fatIgue lIfe compared to the other CFRP In-plane end cuttIng shapes. ApplyIng the trIangular spew fIllets of adhesIve sIgnIfIcantly Increased the end-debondIng and steel beam fracture InItIatIon lIfe of the strengthened Beams.

  • faIlure analysIs and structural behavIour of cfrp strengthened steel I Beams
    Construction and Building Materials, 2012
    Co-Authors: Kambiz Narmashiri, N Ramli H Sulong, Mohd Zamin Jumaat
    Abstract:

    ThIs paper reports the experImental and numerIcal InvestIgatIons on the Carbon FIbre ReInforced Polymer (CFRP) faIlure analysIs and structural behavIour of the CFRP flexural strengthened steel I-Beams. UnderstandIng the CFRP faIlure modes Is useful to fInd solutIons for preventIng or retardIng the faIlures. One non-strengthened control beam and twelve strengthened Beams usIng dIfferent types and dImensIons of CFRP strIps In both experImental test and sImulatIon modellIng studIes were InvestIgated. In the experImental test, four-poInt bendIng method wIth statIc gradual loadIng was applIed. To sImulate the specImens, the ANSYS software In full three dImensIonal (3D) modellIng case and non-lInear analysIs method was utIlIzed. The results show the CFRP faIlure modes used In flexural strengthenIng of steel I-Beams Include below poInt load splIttIng (BS), below poInt load debondIng (BD), end delamInatIon (EDL), and end debondIng (ED). The occurrences and sequences of CFRP faIlure modes depended on the strengthenIng schedule. The structural performance of the CFRP strengthened steel Beams also varIed accordIng to the strengthenIng specIfIcatIons InvestIgated In thIs research.