The program calculates the required thickness of doubler plates using the following algorithms. The shear force in the panel zone is given by: V p =

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1 COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001 STEEL FRAME DESIGN AISC-ASD89 Tehial Note Oe aspet of the esig of a steel framig system is a evaluatio of the shear fores that exist i the regio of the beam olum itersetio kow as the pael zoe. Shear stresses selom otrol the esig of a beam or olum member. However, i a Momet-Resistig frame, the shear stress i the beam-olum joit a be ritial, espeially i framig systems whe the olum is subjete to major iretio beig a the joit shear fores are resiste by the web of the olum. I mior iretio beig, the joit shear is arrie by the olum flages, i whih ase the shear stresses are selom ritial, a this oitio is therefore ot ivestigate by the program. Shear stresses i the pael zoe ause by major iretio beig i the olum may require aitioal plates to be wele oto the olum web, epeig o the loaig a the geometry of the steel beams that frame ito the olum, either alog the olum major iretio or at a agle so that the beams have ompoets alog the olum major iretio. See Figure 1. The program ivestigates suh situatios a reports the thikess of ay require oubler plates. Oly olums with I-shapes are ivestigate for oubler plate requiremets. Also, oubler plate requiremets are evaluate for momet frames oly. No hek is mae for brae frames. The program alulates the require thikess of oubler plates usig the followig algorithms. The shear fore i the pael zoe is give by: b V p = = 1 M b os θ t f V Page 1 of 5

2 Figure 1 Elevatio a Pla of for a Colum of I-Setio Page 2 of 5

3 The omial pael shear stregth is give by R v = 0.6F y t r, for P u 0.4P y or if P u is tesile, a (LRFD K1-9) R v = 0.6F y t r, P u 1.4 for P u > 0.4P y (LRFD K1-10) Py By usig V p = ϕr v, with ϕ = 0.9, the require olum web thikess, t r, a be fou. The extra thikess, or thikess of the oubler plate is give by t p = t r - t w h 418 / F y (LFRD F2-1) where, F y = Colum a oubler plate yiel stress t r = Require olum web thikess t p = Require oubler plate thikess t w = Colum web thikess h = -2t f if wele, - 2k if rolle V p = Pael zoe shear V = Colum shear i olum above F y = Beam flage fores b = Number of beams oetig to olum = Depth of -th beam oetig to olum θ = Agle betwee -th beam a olum major iretio = Depth of olum lear of fillets, equals - 2k M b = Calulate fatore beam momet from the orrespoig loa ombiatio Page 3 of 5

4 R v = Nomial shear stregth of pael P u = Colum fatore axial loa P y = Colum axial yiel stregth, F y A The program reports the largest alulate value of t b for ay of the loa ombiatios base o the fatore beam momets a fatore olum axial loas. The speial seismi requiremets heke by the program for alulatig oubler plate areas epe o the type of framig use; the requiremets heke are esribe herei for eah type of framig. The requiremets heke are base o UBC Setio for frames i Seismi Zoes 0 a 1 a Zoe 2 with Importae fator equal to 1 (UBC , UBC ), o UBC Setio for frames i Seismi Zoe 2 with Importae fator greater tha 1 (UBC , UBC ) a o UBC Setio for frames i Seismi Zoes 3 a 4 (UBC , UBC ). No speial requiremet is heke for frames i Seismi Zoes 0 a 1 a i Seismi Zoe 2 with Importae fator equal to 1 (UBC , UBC ).! I Seismi Zoes 3 a 4, for Speial Momet-Resistig Frames, the pael zoe oubler plate requiremets that are reporte will evelop the lesser of beam momets equal to 0.9 of the plasti momet apaity of the beam (0.9 ϕ b M pb ), or beam momets resultig from speifie loa ombiatios ivolvig seismi loa (UBC a). The apaity of the pael zoe i resistig this shear is take as (UBC a): 2 ϕ v V = 0.6ϕ v F y t p 3bf tf 1 + (UBC a) bt p givig the require pael zoe thikess as t p = V 0.6ϕ v p F y 3b f b t 2 f h 418 / F y (UBC , LRFD F2-1) a the require oubler plate thikess as Page 4 of 5

5 where, t p = t p - t w ϕ v = 0.75, b f = with of olum flage t f = thikess of olum flage t p = require olum web thikess h = - 2t f if wele, - 2k if rolle, a b = epth of eepest beam framig ito the major iretio of the olum.! I Seismi Zoes 3 a 4, for Speial Momet-Resistig Frames, the program heks the followig pael zoe olum web thikess requiremet: t w ( 2t f ) + ( b 2t fb ) 90 (UBC b) If the hek is ot satisfie, it is ote i the output.! I Seismi Zoes 3 a 4, for Eetrially Brae Frames, the oubler plate requiremets are heke similar to oubler plate heks for Speial Momet-Resistig Frames, as esribe above (UBC ). Page 5 of 5