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Sei2013 crosti
 

Sei2013 crosti

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    Sei2013 crosti Sei2013 crosti Presentation Transcript

    • PITTSBURGH, PENNSYLVANIA, MAY 2-4 2013COLLAPSE ANALYSIS OFAMETAL TRUSS STRUCTUREChiara Crosti, Franco Bontempi“Sapienza” University of Roma,chiara.crosti@uniroma1.it, franco.bontempi@uniroma1.it
    • chiara.crosti@uniroma1.it2/22Radiohead’s concert, 2012Image taken from:http://abcnews.go.com/Entertainment/stage-collapses-radiohead-concertkilling/story?id=16587415#.UGrriE3A9_cCountry music concert, 2011Image taken from:http://www.billboard.com/news/Big valley Jamboree, 2009Image taken from:http://www.cbc.ca/news/canada/edmonton/story/2012/01/20/edmonton-charges-stayed-big-valley-jamboree.htmlJovanotti’s concert, 2011Image taken from:http://tg24.sky.it/tg24/cronaca/photogallery/2011/12/12/crollo_palco_concerto_jovanotti_trieste.htmlFORENSIC ASPECTS
    • http://www.udine20.it/wp-content/uploads/2012/03/palco-laura-pausini.jpgCASE STUDYAIM OF THIS WORK:The aim of this work was not to define who made the mistake, but:a. to investigate which kind of “error” could have compromised the safety ofthis structure; and,b. to evaluate the consequence of these “errors” in terms of global structuralresponse.chiara.crosti@uniroma1.it3/22 FORENSIC ASPECTS
    • A temporary structure can be defined as a structure that can be readily and completelydismantled and removed from the site between periods of actual use.They comprise 3 distinct elements:1. The foundations – designed to both support the structure and hold it down (due to wind-uplift, sliding or over-turning).2. The superstructure – to carry all the imposed vertical (gravity) loads safely to the ground,e.g. people, equipment.3. The stability system – bracing and other specialist members to resist horizontal loads, e.g.due to crowd movement and wind loads.TEMPORARY DEMOUNTABLE STRUCTURES (TDM)chiara.crosti@uniroma1.it4/22 FORENSIC ASPECTS
    • A temporary structure can be defined as a structure that can be readily and completelydismantled and removed from the site between periods of actual use.They comprise 3 distinct elements:1. The foundations – designed to both support the structure and hold it down (due to wind-uplift, sliding or over-turning).2. The superstructure – to carry all the imposed vertical (gravity) loads safely to the ground,e.g. people, equipment.3. The stability system – bracing and other specialist members to resist horizontal loads, e.g.due to crowd movement and wind loads.Management &AdministrationDesign Built-up Load-inEVENTLoad-out Break-downTEMPORARY DEMOUNTABLE STRUCTURES (TDM)chiara.crosti@uniroma1.it4/22 FORENSIC ASPECTS
    • SWISS CHEESE MODEL (Reason, 1997)FORENSIC ASPECTSchiara.crosti@uniroma1.it5/22
    • Management &AdministrationInadequate siteinvestigationInappropriateground conditionInadequate safetyplan………..Inadequatestructural designFailure to adoptBuilding CodesInadequate loadsestimation……..Improper construction procedureImproper working positionBreach of regulation or code ofpractice………..SWISS CHEESE MODEL (Reason, 1997)FORENSIC ASPECTSchiara.crosti@uniroma1.it6/22Built-up Load-inDesign
    • Management &AdministrationInadequate siteinvestigationInappropriateground conditionInadequate safetyplan………..Inadequatestructural designFailure to adoptBuilding CodesInadequate loadsestimation……..Improper construction procedureImproper working positionBreach of regulation or code ofpractice………..COLLAPSESWISS CHEESE MODEL (Reason, 1997)FORENSIC ASPECTSchiara.crosti@uniroma1.it6/22Built-up Load-inDesign
    • BUILD-UP PHASES (CASE STUDY)Positioning on the groundof the load distributionplatesPositioning of the bases ofthe columnsAssembling on the floor ofthe roof structure called“Space Roof”Assempled and anchoredsecondary beamsLifting the columns of theroof structure andanchoring the top of thecolumns to the roofAssembling of the hungbeams and othercomponents of the stage(lighting, video, etc.)Rigging phase Delivery of the structurefor its useTechnical-administrativetestingCOLLAPSEINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it7/22
    • INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it8/22BUILD-UP PHASES (CASE STUDY)
    • INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it8/22BUILD-UP PHASES (CASE STUDY)
    • COLLAPSEINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it8/22BUILD-UP PHASES (CASE STUDY)
    • 15/22FINITE ELEMENT MODELINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it9/22tonABC1 216m21.8m33 mabc defg hil ma (ton) 8.7b (ton) 6.5c (ton) 8.7d (ton) 2.3e (ton) 2.3f (ton) 7.75g (ton) 4.3h (ton) 5.6I (ton) 5.6l (ton) 6.7m (ton) 6.7MATERIAL: ALUMINIUMEN AW-6082 T6
    • EUROCODEφ 0.005kc 1.224745 > 1nc 1ks 1.224745 > 1ns 1φ0 0.005N 2.25E+05 NφN 1.13E+03 NThis structure is designed to be indoor; therefore the structural elements weredesigned to carry vertical loads but may not have been designed for lateral loads. Thatcould be a fatal error in the design phase, in fact, following what prescribed in theUNI ENV 1999-1-1:2007, in order to run global analyses, it is necessary to takeaccount of horizontal forces due to the imperfections of the elements composing thestructure.FAILURE TO ADOPT STANDARD PROCEDURESINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.itNO HORIZONTAL LOADSNO BRACING MEMBERS10/22
    • Top of the columnBottom of the columnRigid or HingedRigid or HingedIMPROPER CONSTRUCTION PROCEDUREINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it11/22
    • chiara.crosti@uniroma1.it1 kNRigidRigidA1 kNHingedRigidB1 kNRigidHingedCColumns going through the space roof Column not going through the space roof1 kNRigidRigidA1 kNHingedRigidB1 kNRigidHingedCNode 42Node 42INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEABC12/22
    • RIGIDHINGEDRIGIDAABBCCRIGID RIGID HINGEDRIGIDHINGEDRIGIDRIGID RIGID HINGED16m14mINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEABCλBuckling= 13.57λBuckling= 8.26λBuckling= 2.61λ: Linear Buckling Eigenvaluechiara.crosti@uniroma1.it13/22
    • 036912-1,0 -0,8 -0,6 -0,4 -0,2 0,0LoadFactor(verticalloads)Horizontal Displacement node 42 (m)RIGIDHINGEDB CRIGIDRIGIDARIGIDHINGEDBABCULF=11.3 ULF=7.86 ULF=1.53INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEFINITE ELEMENT ANALYSIS RESULTS (Nonlinear)chiara.crosti@uniroma1.it14/22
    • Cut-off bar,No tension elementTranslation StiffnessBeamRigidlinkColumnHingeRigidUnilateralINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEFINITE ELEMENT ANALYSIS RESULTS (Nonlinear)chiara.crosti@uniroma1.it15/22
    • -2,5E+04-2,0E+04-1,5E+04-1,0E+04-5,0E+030,0E+005,0E+03-0,1 -0,08 -0,06 -0,04 -0,02 0 0,02 0,04 0,06 0,08 0,1Load(N)Displacement (m)Compression TensionMaximum Compressive Strength = 2100 KgMechanical properties for the “cut-off bar”chiara.crosti@uniroma1.it16/22 INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSE
    • 024681012-0,40 -0,35 -0,30 -0,25 -0,20 -0,15 -0,10 -0,05 0,00LoadFactor(verticalloads)Horizontal Displacement node 42 (m)ADDecreasing of 63 %12345678INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEFINITE ELEMENT ANALYSIS RESULTS (Nonlinear)chiara.crosti@uniroma1.it17/22Case D: Column C2
    • 12345678Compression TensionINVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEFINITE ELEMENT ANALYSIS RESULTS (Nonlinear)chiara.crosti@uniroma1.it18/22563487
    • 12345678INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEFINITE ELEMENT ANALYSIS RESULTS (Nonlinear)chiara.crosti@uniroma1.it19/22
    • INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it20/22
    • INVESTIGATION ON TECHINAL CAUSES OF THE COLLAPSEchiara.crosti@uniroma1.it21/22
    • CONCLUSIONchiara.crosti@uniroma1.itInadequate siteinvestigationSWISS CHEESE MODEL (Reason, 1997)Management &AdministrationDesign Built-up Load-inCOLLAPSE12345678NO HORIZONTAL LOADSNO BRACING MEMBERSFailure to adoptBuilding CodesImproper constructionprocedureCOLLAPSE22/22
    • Inadequate siteinvestigationSWISS CHEESE MODEL (Reason, 1997)chiara.crosti@uniroma1.itManagement &AdministrationDesign Built-up Load-inCOLLAPSENO HORIZONTAL LOADSNO BRACING MEMBERSFailure to adoptBuilding CodesImproper constructionprocedureCOLLAPSE22/22 CONCLUSION