UL3l0N A3PLC13 l0R 1LRR0Rl31 RL3l31AN1 BulLUlN03lN1R0UuC1l0NOI|c ccsi-: oi civilia: o: couuc:cial |uilci:-s to wit|sta:c t|c ciiccts oi a tc::o:ist |last is u:li|c t|c ccsi-: oi uilita:v i:stallatio:s o: t|c ccsi-: oi cu|assv |uilci:-s.OI|c o|jcctivcs oi t|c t:uctu:al l:-i:cc:i:- Guiccli:cs io: t|c Dcsi-: oi :cw lu|assv luilci:-s a:c to :cvc:t |cavv caua-c to couo:c:ts a:c st:uctu:al collasc. OA:c|itcctu:al a:c st:uctu:al icatu:cs lav a si-:iiica:t :olc i: cctc:ui:i:- |ow t|c |uilci:- will :cso:c to t|c |last loaci:-. I|csc icatu:cs ca: i:clucc acjacc:t o: u:cc:-:ou:c a:|i:-. t:a:sic: -i:cc:s. sla| co:ii-u:atio:s. a:c st:uctu:ali:auc svstcusLXPLC1LU 1LRR0Rl31 BLA313 0N 31RuC1uRL3OIternai car bombOInternai car bombOInternai package Osuicidai car bombsA10R CAu3L3 0l LllL L033 Al1LR 1L BLA31Ollvi:- cc|:is Ol:o|c: -lassOuo|c a:c ii:c Olloc|cc -lassOlowc: lossOouuu:icatio:s |:ca|cow:Ol:o-:cssivc collasc oi st:uctu:c00AL3 0l BLA31 RL3l31AN1 UL3l0NOkccucc t|c scvc:itv oi i:ju:vOlacilitatc :cscucOlxccitc :cai:OAccclc:atc t|c sccc oi :ctu:: to iull oc:atio:s.BA3lC RL0ulRLLN13 10 RL3l31 BLA31 L0AU3I|c ii:st :cqui:cuc:t is to cctc:ui:c t|ct|:cat. I|cuajo:t|:catiscauscc|vtc::o:ist|ou|i:-s. I|c t|:cat io: a co:vc:tio:al |ou| isccii:cc |v two cquallv iuo:ta:t clcuc:ts.OI|c |ou| sizc :o: c|a:-c wci-|t. OI|c sta:coii cista:cct|c ui:iuuu -ua:a:tccc cista:cc |ctwcc: t|c |last sou:cc a:c t|c ta:-ctA:ot|c: :cqui:cuc:t is to |cc t|c |ou| as ia: awav as ossi|lc. |v uaxiuizi:- t|c |ccout cista:cc. :o uattc: w|at sizc t|c |ou|. t|c caua-c will |c lcss scvc:c t|c iu:t|c: t|c ta:-ct is i:ou t|c sou:cc.1RLA1LN13 PR0vlULU 10 vARl0u3 PAR13 0l A 31RuC1uRL 10 lPR0vL BLA31 RL3l31lN0 LCANl3lL00R 3LAB31. \o:c attc:tio: uust |c aic to t|c ccsi-: a:c cctaili:- oi cxtc:io: |avs a:c lowc: iloo:s. w|ic| a:c t|c uost susccti|lc to |last loacs .!. li vc:tical clca:a:cc is a :o|lcu. s|ca: |cacs cu|ccccc i: t|c sla| will iu:ovc t|c s|ca: :csista:cc a:c iu:ovc t|c a|ilitv oi t|c sla| to t:a:sic: uouc:ts to t|c coluu:s !. l: cxtc:io: |avslowc: iloo:s. c:o a:cls a:c coluu: caitols a:c :cqui:cc to s|o:tc: t|c ciicctivc sla| lc:-t| a:c iu:ovc t|c u:c|i:- s|ca: :csista:cc+. I|c sla|coluu: i:tc:iacc s|oulc co:tai: closcc|oo sti::u :ci:io:ccuc:t :oc:lv a:c|o:cc a:ou:c ilcxu:al |a:s wit|i: a :csc:i|cc cista:cc i:ou t|c coluu: iacc .. lottou :ci:io:ccuc:t uust |c :oviccc co:ti:uous t|:ou-| t|c coluu:. I|is :ci:io:ccuc:t sc:vcs to :cvc:t |:ittlc iailu:c at t|c co::cctio: a:c :oviccs a: altc::atc ucc|a:isu io: ccvcloi:- s|ca: t:a:sic: o:cc t|c co:c:ctc |as u:c|cc t|:ou-|. C0LuN31. I|c otc:tial io: ci:cct latc:al loaci:- o: t|c iacc oi t|c coluu:s. :csulti:- i:ou t|c |last :cssu:c a:c iuact oi cxlosivc cc|:is. :cqui:cs t|at t|c lowc: iloo: coluu:s |c ccsi-:cc wit| accquatc cuctilitv a:c st:c:-t| !. I|c c:iuctc: coluu:s suo:ti:- t|c lowc: iloo:s uust also |c ccsi-:cc to :csist t|is cxt:cuc |last ciicct !. l:casi:- t|csc lowc:iloo: coluu:s i: a stccl jac|ct will :ovicc co:ii:cuc:t. i:c:casc s|ca: caacitv. a:c iu:ovc t|c coluu:s' cuctilitv a:c st:c:-t|. A: altc::ativc. w|ic| :oviccs siuila: |c:ciits. is to cu|cc a stccl coluu: wit|i: t|c c:iuctc: co:c:ctc coluu:s o: wall scctio:S1FFl 140KF1+. lo: suallc: c|a:-c wci-|ts. si:al :ci:io:ccuc:t :oviccs a ucasu:c oi co:c co:ii:cuc:t t|at -:catlv iu:ovcs t|c caacitv a:c t|c |c|avio: oi t|c :ci:io:ccc co:c:ctc coluu:s u:cc: cxt:cuc loac. 1RAN3lLR 0lRULR3OI|c |uilci:- :clics o: t:a:sic: -i:cc:s at t|c to oi t|c at:iuu to cist:i|utc t|c loacs oi t|c coluu:s a|ovc t|c at:iuu to t|c acjacc:t coluu:s outsicc t|c at:iuu. I|c t:a:sic: -i:cc: sa:s t|c wict| oi t|c at:iuu. w|ic| i:su:cs a coluu:i:cc a:c|itcctu:al sacc io: t|c c:t:a:cc to t|c |uilci:-.OI:a:sic: -i:cc:s tvicallv co:cc:t:atc t|c loac|ca:i:- svstcu i:to a suallc: :uu|c: oi st:uctu:al clcuc:ts.OI|c coluu: co::cctio:s. w|ic| suo:t t|c t:a:sic: -i:cc:s. a:c to :ovicc sustai:cc st:c:-t| ccsitc i:clastic ccio:uatio:s.OI|c coluu: co::cctio:s. w|ic| suo:t t|c t:a:sic: -i:cc:s. a:c to :ovicc sustai:cc st:c:-t| ccsitc i:clastic ccio:uatio:s.3LAR wALL3usc a wcllcist:i|utcc latc:alloac :csisti:- ucc|a:isui: t|c|o:izo:tal iloo:la:.I|is ca:|caccoulis|cc|vusi:-scvc:als|ca:wallsa:ou:ct|cla:oi t|c|uilci:-t|iswill iu:ovct|covc:all scisuic as wcll as t|c |last |c|avio: oi t|c |uilci:-.li acci:- uo:c s|ca: walls is :ot a:c|itcctu:allv icasi|lc. a cou|i:cc latc:alloac :csisti:- ucc|a:isu ca: also |c uscc. A cc:t:al s|ca: wall a:c a c:iuctc: uouc:t:csisti:- i:auc will :ovicc io: a |ala:ccc solutio:. I|c c:iuctc: uouc:t:csisti:- i:auc will :cqui:c st:c:-t|c:i:- t|c sa:c:cl |caus a:c t|c co::cctio:s to t|c outsicc coluu:s. I|is will also :csult i: |cttc: :otcctio: oi t|c outsicc coluu:s.L0wLR lL00R LX1LRl0ROI|c a:c|itcctu:al ccsi-: oi t|c |uilci:- oi i:tc:cst cu::c:tlv calls io: wi:cow -lass a:ou:c t|c ii:st iloo:. u:lcss t|is a:ca is co:st:uctcc i: :ci:io:ccc co:c:ctc. t|c caua-c to t|c lowc: iloo: st:uctu:al clcuc:ts a:c t|ci: co::cctio:s will |c quitc scvc:c. o:scquc:tlv. t|c i:ju:v to t|c lowc: iloo: i:|a|ita:ts will |c cquallv scvc:c. Iwo sizcs oi c|a:-cs ca: |c ciscusscc.1. Io :otcct a-ai:st a suall c|a:-c wci-|t. a :oui:al !00 uu :1! i:. t|ic| wall wit| 0.! stccl cou|lv :ci:io:ccc i: |ot| ci:cctio:s ui-|t |c :cqui:cc. !.lo: i:tc:ucciatc c|a:-c wci-|t :otcctio:. a +o0 uu :1 i:. t|ic| wall wit| 0.. stcclui-|t |c :ccccc. 31ANU 0ll Ul31ANCLOI|c |cc out cista:cc. wit|i: w|ic| cxlosivcslacc: vc|iclcs uav :ot c:ct:atc. uust |c uaxiuizcc a:c -ua:a:tccc. As wc all |:ow. t|c -:catc: t|c sta:coii cista:cc. t|c uo:c t|c |last io:ccs will cissiatc :csulti:- i: :ccuccc :cssu:cs o: t|c |uilci:-. cvc:al :ccouuc:catio:s ca: |c uacc to uai:tai: a:c iu:ovc t|c sta:coii cista:cc io: t|c |uilci:- u:cc: co:sicc:atio:O usc a:ti:au |olla:cs o: la:-c la:tc:s. laccc a:ou:c t|c c:ti:c c:iuctc:. I|csc |a::ic:s uust |c ccsi-:cc to :csist t|c uaxiuuu vc|icula: iuact loac t|at coulc |c iuoscc. lo: uaxiuuu ciicctivc:css. t|c |a::ic:s|olla:cs o: la:tc:suust |c laccc at t|c cu:|. ,397,2 bo||,7/8OI|c u|lic a:|i:- lot at t|c co::c: oi t|c |uilci:- uust |c sccu:cc to -ua:a:tcc t|c :csc:i|cc |ccout cista:cc i:ou t|c iacc oi t|c st:uctu:c. l:cic:a|lv. t|c a:|i:- lot s|oulc |c cliui:atcc. Ot:cct a:|i:- s|oulc :ot |c c:uittcc o: t|c :ca: sicc oi t|c st:cct. acjacc:t to t|c |uilci:-. c+xL x1UDY -1ORLD 1R+DL cLN1LR cOLL+1xLI|c collasc oi t|c Wo:lc I:acc c:tc: :WI towc:s o: ctcu|c: 11. !001. was as succc: as it was c:auatic. t|c coulctc ccst:uctio: oi suc| uassivc |uilci:-s s|oc|cc :ca:lv cvc:vo:c. luucciatclv aitc:wa:c a:c cvc: tocav. t|c:c is wiccs:cac scculatio: t|at t|c |uilci:-s wc:c st:uctu:allv cciicic:t. t|at t|c stccl coluu:s ucltcc. o: t|at t|c ii:c su:cssio: cquiuc:t iailcc to oc:atc. 1lF lFSlCNI|c towc:s wc:c ccsi-:cc a:c |uilt i: t|c uic19o0s t|:ou-| t|c ca:lv 190scac| towc: was o+ u squa:c. sta:ci:- +11 u a|ovc st:cct lcvcl a:c !1 u |clow -:acc. I|is :ocuccs a |ci-|ttowict| :atio oi o.. I|c total wci-|t oi t|c st:uctu:c was :ou-|lv .00.000 t. I|c |uilci:- is a |u-c sail t|at uust :csist a !!. |u| |u::ica:c. lt was ccsi-:cc to :csist a wi:c loac oi ! |laa total oi latc:al loac oi ..000 t.l: o:cc: to ua|c cac| towc: caa|lc oi wit|sta:ci:- t|is wi:c loac. t|c a:c|itccts sclcctcc a li-|twci-|t c:iuctc: tu|c ccsi-: co:sisti:- oi !++ cxtc:io: coluu:s oi !o cu squa:c stccl |ox scctio: o: 100 cu cc:tc:s.OI|is c:uittcc wi:cows uo:c t|a: o:c|ali uctc: wicc. l:sicc t|is outc: tu|c t|c:c was a ! u +0 u co:c. w|ic| was ccsi-:cc to suo:t I|c wci-|t oi t|c towc:. lt also |ouscc t|c clcvato:s. t|c stai:wclls. a:c t|c ucc|a:ical :isc:s a:c utilitics. Wc| joists 0 cu tall co::cctcc t|c co:c to t|c c:iuctc: at cac| sto:v. o:c:ctc sla|s wc:c ou:cc ovc: t|csc joists to io:u t|c iloo:s. l: cssc:cc. I|c |uilci:- is a: c--c:atc co:st:uctio:. i.c. 9.c:cc:t ai:.I|c c--c:atc co:st:uctio: uacc a :ccu:ca:t st:uctu:c :i.c.. ii o:c o: two coluu:s wc:c lost. t|c loacs woulc s|iit i:to acjacc:t coluu:s a:c t|c |uilci:- woulc :cuai: sta:ci:-. I|c WI was :iua:ilv a li-|twci-|t stccl st:uctu:c. |owcvc:. its !++ c:iuctc: coluu:s uacc it o:c oi t|c uost :ccu:ca:t a:c o:c oi t|c uost :csilic:t s|vsc:ac:s.DL1+ILx OI 1HL cOLL+1xL1HL +IR1L+NL Im1+c1I|c ca:lv :cws :co:ts :otcc |ow wcll t|c towc:s wit|stooc t|c i:itial iuact oi t|c ai:c:ait. |owcvc:. w|c: o:c :cco-:izcs t|at t|c |uilci:-s |ac uo:c t|a: 1.000 tiucs t|c uass oi t|c ai:c:ait a:c |ac |cc: ccsi-:cc to :csist stcacv wi:c loacs oi !0 tiucs t|c wci-|t oi t|c ai:c:ait. t|is a|ilitv to wit|sta:c t|c i:itial iuact is |a:clv su::isi:-. lu:t|c:uo:c. si:cc t|c:c was :o si-:iiica:t wi:c o: ctcu|c: 11. t|c outc: c:iuctc: coluu:s wc:c o:lv st:csscc |cio:c t|c iuact to a:ou:c 1! oi t|ci: !00 \laccsi-: allowa|lc. OW|ilc t|c ai:c:ait iuact u:cou|tcclv ccst:ovcc scvc:al coluu:s i: t|c WI c:iuctc: wall. t|c :uu|c: oi coluu:s lost o: t|c i:itial iuact was :ot la:-c a:c t|c loacs wc:c s|iitcc to :cuai:i:- coluu:s i: t|is |i-|lv :ccu:ca:t st:uctu:c. i cqual o: cvc: -:catc: si-:iiica:cc cu:i:- t|is i:itial iuact was t|c cxlosio: w|c: 90.000 l -allo:s oi jct iucl. cou:isi:- :ca:lv 1! oi t|c ai:c:ait`s wci-|t. i-:itcc. I|c c:sui:- ii:c was clca:lv t|c :i:cial causc oi t|c collasc1L C0LLAP3LOI|c c:iuctc: tu|c ccsi-: oi t|c WI was |i-|lv :ccu:ca:t. lt su:vivcc t|c loss oi scvc:al cxtc:io: coluu:s cuc to ai:c:ait iuact. |ut t|c c:sui:- ii:c lcc to ot|c: stccl iailu:cs. O\a:v st:uctu:al c:-i:cc:s |clicvc t|at t|c wca| oi:tswc:c t|c a:-lc clis t|at |clc t|c iloo: joists |ctwcc: t|c coluu:s o: t|c c:iuctc: wall a:c t|c co:c st:uctu:c .OWit| a 00 la iloo: ccsi-: allowa|lc. cac| iloo: s|oulc |avc |cc: a|lc to suo:t a:oxiuatclv 1.!00 t |cvo:c its ow: wci-|t. I|c total wci-|t oi cac| towc: was a|out .00.000 t.O As t|c joists o: o:c o: two oi t|c uost |cavilv |u::cc iloo:s -avc wav a:c t|c outc: |ox coluu:s |c-a: to |ow outwa:c. t|c iloo:s a|ovc t|cu also icll. I|c iloo: |clow :wit| its 1.!00 t ccsi-: caacitv coulc :ot suo:t t|c :ou-|lv +..000 t oi tc: iloo:s :o: uo:c a|ovc c:as|i:- cow: o: t|csc a:-lc clis. I|is sta:tcc t|c coui:o ciicct t|at causcc t|c |uilci:-s to collasc wit|i: tc: scco:cs. |itti:- |ottou wit| a: cstiuatcc sccc oi !00 |u c: |ou:. BuIIDIs RIsIs1 DIRI1 IRPII HI1sOli t|c ccsi-: tc::o:ist attac| is siuila: to t|at oi ct. 11. ca: |uilci:-s |c -ivc: t|c caacitv to ucct t|is ccua:c Io a:swc: t|is qucstio:. it is iuo:ta:t to u:cc:sta:c t|c |vsics at wo:| w|c: a la:c i: ili-|t is stocc |v a |uilci:-.OIo sto a loci:- o t:avcli:- i: cxccss oi .00 uilcs c: |ou: i: a cista:cc oi a icw icct woulc ta|c a cccclc:atio: io:cc i: cxccss oi +00 uillio: ou:cs. Olac| towc: oi t|c Wo:lc I:acc c:tc: was ccsi-:cc io: a total |o:izo:tal io:cc oi a|out 1. uillio: ou:cs. I|c total ccsi-: wi:c loac io: a uo:c couuo:lv sizcc |i-|:isc. sav. +0 sto:ics tall. woulc |c a|out + uillio: ou:cs.OA:ot|c: a:t oi t|c a:swc: to t|is qucstio: lics i: t|c wav t|at t|c cxtc:io: oi t|c |uilci:- was st:uctu:cc. I|c cxtc:io: coluu:s wc:c 1+i:c| squa:c wclccc stccl |ox coluu:s saccc at +0 i:c|cs o: cc:tc:. I|is uca:s t|at t|c:c was o:lv !o i:c|cs clca: |ctwcc: cac| coluu:. I|c coluu:s wc:c i:tc-:al wit| t|c stccl sa:c:cls |caus a:c io:ucc cssc:tiallv a solic wall oi stccl wit| c:io:atio:s io: wi:cows.O a: |uilci:-s |c ccsi-:cc io: ci:cct ai:la:c |its Ycs a:c :o. Ycs. io: suall ai:c:ait. A ccii:itc :o. io: la:-c couuc:cial ai:c:ait.0w CAN wL lNllLL 1L CANCL 0l PR00RL33lvL C0LLAP3LOlccausc t|c towc:s ultiuatclv collascc wit| o:c iloo: c:as|i:- cow: uo: t|c :cxt. it |as |cc: callcc a :o-:cssivc collasc. Ol: t|c casc oi t|c Wo:lc I:acc c:tc: t|c:c wc:c a|out +0 coluu:s lost o: o:c iacc oi cac| oi t|c towc:s a:c t|c:c was :o :oa-atio: oi collasc i:ou t|is loss.O A :cw Yo:| ii:c c|ici w:otc t|at cxc:ic:ccc ii:cii-|tc:s |:ow t|at t|c |uilci:-s t|at a:c uost susccti|lc to :o-:cssivc collasc a:c |uilci:-s t|at a:c wcllticc to-ct|c: :i.c.. a|lc to t:a:sic: |uilci:- loacs i:ou o:c clcuc:t to a:ot|c:. suc| as a coluu:OYct. vi:tuallv cvc:v st:uctu:al c:-i:cc: will acvisc t|at o:c oi t|c |cst wavs to :cvc:t :o-:cssivc collasc is to tic t|c |uilci:- to-ct|c:.OI|c ciiic:c:cc is t|at t|c c:-i:cc: is t|i:|i:- a|out losi:- a coluu: o: two a:c t|c ii:c c|ici is tal|i:- a|out losi:- a w|olc a:t oi a |uilci:-. O At lcast six saictv svstcus :csc:t i: t|c Wo:lc I:acc c:tc: towc:s wc:c coulctclv a:c iuucciatclv cisa|lcc o: ccst:ovcc uo: iuact. ii:c:ooii:-. autouatic s:i:|lc:s. coua:tuc:talizatio: a:c :cssu:izatio:. li-|ti:-. st:uctu:c a:c cxit stai:s.C0NCLu3l0NOI|c:c a:c st:uctu:al tcc|:iqucs t|at ca: i:c:casc t|c caacitv oi |uilci:- st:uctu:cs to :csist cc:tai: |i:cs oi tc::o:ist attac|s. lowcvc:. t|c:c is a|solutclv :o :clia|lc wav to ccsi-: io: t|c iuact oi a la:-c scalc couuc:cial ai:li:c:.IlA:l u`