Introduction. ENCE 455 Design of Steel Structures. IV. Laterally Support Beams. Introduction (cont.)

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1 ENCE 455 Desig o Seel Srucures V. Laerall Suppor Beams C. C. u, P.D., P.E. Civil ad Eviromeal Egieerig Deparme Uiversi o arlad roducio olloig sujecs are covered: roducio Saili Laerall suppored eams Serviceaili Sear sreg Coceraed loads Biaial edig eadig: Capers 7 ad 9 o Salmo & Joso ASC Seel aual Speciicaios Capers B (Desig equiremes), (Beams ad Oer leural emers), L (Serviceaili Desig), ad Appedi (Desig or Podig) roducio (co.) leural memerseams are deied as memers aced upo primaril rasverse loadig, oe gravi dead ad live load eecs. Tus, leural memers i a srucure ma also e reerred o as: Girders usuall e mos impora eams, ic are requel a ide spacig. Joiss usuall less impora eams ic are closel spaced, requel i russ-pe es. Purlis roo eams spaig eee russes. Srigers logiudial ridge eams spaig eee loor eams. Girs orizoal all eams servig pricipall o resis edig due o id o e side o a idusrial uildig, requel supporig corrugaed sidig. roducio (co.) Beam Girder Liels memers supporig a all over ido or door opeigs ased o loorramig Program 4

2 Eample o a Tpical loor Pla Eample o a Tpical Seel Srucure 5 6 Eac jois suppors a area equal o is spa imes al e disace o e jois o eier side. Te joiss raser eir loads o e supporig russ girders. Jois oo Load Pa Triuar Area oo deck rasers load o supporig joiss. Load ress o roo deck Te pier suppors al e area suppored e russ girder plus area rom oer srucural elemes a i suppors. Eac russ girder suppors a area equal o is spa imes al e disace o e girder o eier side. 7 Ed Wall ramig or laeral pressures, e sidig spas eee e orizoal girs (e aoer ac ord or a eam!) Te girs suppor al e sidig o e adjace girs. Tis is e riuar area or oe gir. Te girs raser eir laeral load o e supporig eamcolums. Te eam-colums raser eir laeral loads equall o e roo ad oudaio. 8

3 Saili Te laerall suppored eams assume a e eam is sale up o e ull plasic codiio, a is, e omial sreg is equal o e plasic sreg, or = p saili is o guaraeed, e omial sreg ill e less a e plasic sreg due o Laeral-orsioal ucklig (LTB) lage ad e local ucklig (LB & WLB) We a eam eds, oe al (o a doul smmeric eam) is i compressio ad, aalogous o a colum, ill uckle. 9 Saili (co.) Ulike a colum, e compressio regio is resraied a esio regio (e oer al o e eam) ad e ouard delecio o e compressio regio (leural ucklig) is accompaied isig (orsio). Tis orm o isaili is ko as laeral- orsioal ucklig (LTB) LTB ca e preveed laeral racig o e compressio lage. Te mome sreg o e eam is us corolled e spacig o ese laeral suppors, ic is ermed e uraced leg. 0 Saili (co.) lage ad e local ucklig (LB ad WLB, respecivel) mus e avoided i a eam is o develop is calculaed plasic mome. Saili (co.) our caegories o eavior are so i e igure: Plasic mome sreg p alog i large deormaio. elasic eavior ere plasic mome sreg p is acieved u lile roaio capaci is eiied. elasic eavior ere e mome sreg r, e mome aove ic residual sresses cause ielasic eavior o egi, is reaced or eceeded. Elasic eavior ere mome sreg cr is corolled elasic ucklig.

4 Laerall Suppored Beams Te sress disriuio o a pical idelage sape sujeced o icreasig edig mome is so elo Laerall Suppored Beams (co.) e service load rage e secio is elasic as i (a) We e ield sress is reaced a e ereme ier (), e ield mome is = = S (7..) We e codiio (d) is reaced, ever ier as a srai equal o or greaer a = E s, e plasic mome p is da Z (7..) P A Were Z is called e plasic modulus 4 Laerall Suppored Beams (co.) Noe a raio, sape acor, p is a proper o e cross-secioal sape ad is idepede o e maerial properies. = p = ZS (7..) Values o S ad Z (aou o ad aes) are preseed i e Seel aual Speciicaio or all rolled sapes. or W-sapes, e raio o Z o S is i e rage o.0 o.5 (Salmo & Joso Eample 7..) 5 Laerall Suppored Beams (co.) Te ASC sreg requireme or eams: u (7.4.) Compac secios: = p = Z (7.4.) Nocompac secios: = r = ( r ) S =0.7 S (7.4.) Pariall compac secios p P ( p r ) P (7.4.4) r p ere = or -saped memer lages = or eam e r, p rom Salmo & Joso Tales 7.4. & or ASC Tale B4. (Salmo & Joso Eample 7.4.) Sleder secios: We e idickess raio eceed e limis r o ASC-B4. 6

5 Delecio Serviceaili o Beam ASC Secio L: Deormaios i srucural memers ad srucural ssem due o service loads sall o impair e serviceaili o e srucure ASD - ma = 5L 4 (84E) As a guide i ASD Commear L. - L40 (roo); L00 (arciecural); L00 (movale compoes) Pas guides (sill useul) lised i Salmo & Joso - loor eams ad girders Ld 800, ksi o sock or viraor loads, large ope area Ld 0 - oo purlis, ecep la roos, Ld 000 (Salmo & Joso Eample 7.6.) 7 Serviceaili o Beam Podig (ASC Appedi, Sec..) C p + 0.9C s 0.5 d 5(s 4 )0-6 ere C p = L s L p4 (0 7 p ) C s = SL s4 (0 7 s ) L p = Colum spacig i direcio o girder L s = Colum spacig perpedicular o direcio o girder p = mome o ieria o primar memers s = mome o ieria o secodar memers 8 d = mome o ieria o e seel deck Sear o olled Beams Geeral orm v = VQ() ad average orm is v = VA =V(d ) (7.7.7) ASC- v V V u (7.7.) ere v =.0 V = 0.6 A or eams iou rasverse sieers ad.4e Coceraed Loads ASC-J0. u (7.8.) Local e ieldig (use & i ASC Tale 9-4). erior loads = (5k + N) (7.8.). Ed reacios = (.5k + N) (7.8.) 9 0

6 Coceraed Loads (co.) ASC-J0. (co.) We Cripplig (use, 4, 5 & 6 i ASC Tale 9-4). erior loads (7.8.8). Ed reacios (7.8.9) or Nd 0. (7.8.0) or Nd>0. E d N E d N.5 E d N Coceraed Loads (co.) ASC-J (co.) Sidesa We Bucklig. We e compressio lage is resraied agais roaio or ( )(L ). (7.8.7) i >. = o limi. We e compressio lage is o resraied agais roaio: or ( )(L ).7 (7.8.8) i >.7 = o limi r L C r L C Geeral leural Teor (Salmo & Joso Eample 7.0.) (a) Agle ree o ed i a direcio (c) Agle resraied o ed i e verical plae 4 Biaial Bedig o Smmeric Secios ASC-H (7..) (7..6) (Salmo & Joso Eample 7.8.) (or coceraed loads applied o olled eams) (Salmo & Joso Eample 7..) (or iaial edig) u u S S S