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HomeMy WebLinkAboutPOST FRAME BUILDING STRUCTURAL CALCULATION - 08-00121 - 357 E 1st N - PolebarnCE EN, 0 S 0 0112, 1 ALL10 )-1 � ." - P o e, ern Revisions 3/21 x`200 POST FRAME BUILDING STRUCTURAL CALCULATION (This structure has been analyzed and designed for structural adequacy only.) PROJECT No. 200197 BUILDING OWNER / LOCATION: Gaylon Stucki 7300 E. Foothill Road Idaho Falls, ID 83401 CLIENT: Farm & Home Custom Buildings PO Box 675 Rexburg, ID 83440 ENGINEER: I MAR 2 1 MODS r Lt::) CFS F BU Property of Alliance Engineering of Oregon, Inc. Unauthorized duplication prohibited. Cop ri ht © Alliance Engineering of Oregon, Inc. 2700 Market Street N.E. Alliance Engineering of Oregon, Inc. Phone: (503) 589-1727 Salem, OR 97301 www.aeoregon.com Fax: (503) 589-1728 10%1912007 200197 (Stucki) 40x60x14.xmcd 1 This is a post -frame building with wooden trusses or rafters and preservately treated posts Haat are pressure treated for ground contact. Post size, post embedment depth, post hole diameter and backfill is givers in the body of the calculation. The building will depend on the diaphragm: action of the roof and wall sheathing for lateral stability. The posts will be modeled as propped cantilevers Haat are fixed at the base and propped by the deep beam action of the roof. The roof structure spans horizontally between the wall diaphragms where it is simply supported. The post frames will be assumed to act as a unit. Wind loads will be imposed on the windward and leeward sides of the building simultaneously. The actual post length for beading will be assumed to be measured from top of the post hole backfill to the top of the corbel black. If there is no concrete floor, the concrete backfill will provide lateral constraint in the windward and leeward direction. If a concrete floor is used, lateral restraint for the post will be provided at the around line by the concrete floor. REFERENCES: 2003 Edition of the International Building Cade 2. ASCE 7--02 - Minimum Design Loads for Buildings and ether Structures American Society of Civil Engineers, 2003 3. 2001 Edition, National Design Specification INNS) Supplement For Viood Construction, American Woad Counsel !0119i2007 20019 (Stucki) 40x60x14.x-mcd 3 SUS AWf OF DESIGN LUES'Contin ed)' Footing and Post Hole Des. n Values: q,od := 1500 psf (Assumed soil =vertical bearing capacity) dm_f�c,.a := 2.5 ft (Diameter of footing) 55o;a = 150 psf (Assumed soil lateral bearing capacity) Mesion Loads for Building: Wind Design Values: Roof Isoad t?esi€a�a Valrses Fastest wind speed (3 second gust) p8:= 47 lbs Ground snow load v 4 s d := 90 MRI prcof := 35 lbs Roof snow load =Wind Exposure: Pd := 3 lbs Roof dead load pd" := 0 lbs Additional truss bottom chord =earl load (if applicable) Seismic Dgsian S,:= 61.0 Mapped spectral acceleration for short period Si := 18.8 Mapped spectral acceleration for t second period 'E.'= L0 Importance factor W = Dead load of building (See analysis below) R,:= 7 Response modification factor (GO TO LAST PAGE FOR SUMMARY OF RESULTS) 10119/2-007 200i97 (Stucki! 41?x60xi4.xMr-d 4 SNOW LOAD ANALYSIS: Design per ASCE 7-02 For roof slopes greater than 5 degrees, and less than 70 degrees. pg'b - 4 psi Ground Snow Load (from above)) C,:= 1.0 Exposure factor Ct := 1.0 Thermal Factor C., = 1.00 Roof slope factor 1 = 1.0 Importance factor P. Flat roof snow load, psf (see analysis below) ps= Seeped root snow load, psf! (see analysis belong) Determine pr and A, pf:= -7•C.- Ct-1,-pg pf = 32.4 psf Flat roof snow load !Vote. This is 131C9T the snow Ps = 1 Cs p,=32,9- psf Sloped (balanced) roof snow load load used for design -See psu at bottorn of page. Deterrnine roof s noxy load to be used for structural design P Qof = 35 psf Roof snow load to be used for structural design per agency specifications 1011912007 200197 (utucki) 4Ox50x14.xmcd 5 WIND ANALYSIS: vessgn per 1BC 2003 Method 2 - Anal ical Procedure 1,,,:= 1.0 Importance Factor Vwhad = 90 Basic Wind Speed kd.= .85 Wind Directionality Factor k = 1.0 Topographic Factor kZ = 0.866 Wind Exposure Factor qh := .00256 -kms kt-kd-Vwi, d TW qh = 15.27 psf Calculated Wind Pressures: Windward Eave tall: qww = gh-GCpfww qww = 7.3 psf Windward Gable `ykall: gwwg := gh. GCpfwwg gwwg = 6.11 psf Windward Roof: qwr:= gh•GCp&�. qwr = -10-53 psf Wall Elements: 9— -= nl,-GC fi. qwe = -14.81 psf Internal Wind Pressure 1+1=' qi := gh-GCpi ql = 2.75 psf Velocity Pressure Leeward Eave Wall: qlw := qh-GCpflw glw = -5.72 psi Leeward Gable Wall: glwg:= gh.GCpiiiwg gtwg = -4.43 psf Leeward Roof: qh..= qh-GCpfir qh. = -6.66 psf Raaf Elements: q,= gh"cicpfr qr = -20.61 psf 1011912907 209197 3tucki) 40x6jx14.xmcd 6 STEP 1: CALCULATE THE SHEAR STIFFNESS OF THE TEST PANEL This procedure relies on tests conducted by the National Frame Builders Association:. The test was conducted using 29 gauge ribbed steel panels. These ribbed steel panels are similar to jtrongpanel, iavorclad, and Delta -Rib which are in common use by builders in this area. The material and section properties for the test panels are thus reasonable and will be used throughout. The stiffness of the test pastel was calculated to be: c = 2166 Malin STEP 2: CALCULATED ROOF DIAPHRAGM STIFFNESS OF THE TEST PANEL (E X Q (2 X (I +V) `` (91p) } (K21 (b' X t)h2)) Where: E = 27.6x1 G,,6 psi (modulus of elasticity for steep t = 0.017" (thickness of 29 gauge steel) V = 0.3 (Poisson's Ratio for steel), gfp - 1.139 ratio of sheathing corrugation length to corrugation pitch b'= 144" (12'-0" length of test panel) STEL 2.1 This equation was set equal to the stiffness of the test panel (2166 lblin) and the unknown value (K2) was solved for. K2 = 1276 in4 sheet edge purlin fastening constant STEP 2.2: Use new building width to determine stiffness of new roof diaphragm (ch K-, = 17-715 lbf /ft t:= 0-017 in 14-036 deg (Angie of roof pitch from horizontal) b. = 247 in = 27500000 C _= E-1 K, c = 6229 IV l in '`61T t) 11� 10A W2L i7 2010197 g z:�-tucki) 40x6Oxf 4.xmcd 7 STEP 2.3 & 2.4: Calculate the equivalent horizontal roof stiffness (ch) for the full roof: Since cl, is for the full roof, the roof lenclth must be ratioed by the aspect ratio of the roof panel (b I a) where "a" is the truss spacing in inches. av C -= 2-i-z3�i^) tt a= 144 in ch = 20144 lbf f in STEP 3: CALCULATE THE STIFFNESS OF THE POST FRAME (k): Since the connection between the posts and the rafters can be assumed to be a pinned ioint, the model for the post frame can be assumed to be the sum of tl<vo cantilevers (the posts) that act in parallel. The stiffness of the post frame can be calculated from the amount of force required to deflect the system one inch. The spring constant (k) in pounds per inch of deflection results directly. k = 445 lbf1in STEP 4: CALCULATE TOTAL SIDE SWAY FORCE ,R&: Apply wind loads to the walls to determine moment (1lllw-nd), fiber stress (fv�ind) and end reaction at prop point (R). Calculate Total Wind pressure: q,e igqu-cv — qlu 10, i0, q,,, — giwIl qe = 13.02 psf _ � a t1�� th,Gt qI ti 12- 1 1 cltot qu,,prr't q, -,Mt = 13-02 pli qt,,t = 13.02 pli z 1kin.d -= 11tot- Mi -wind = 39601 in-lbf i- tk�r'llh5 309 psi 1�3st_hszc R ' zltctt R = ;b2 lbs Y STEP 5: CALCULATE THE RATIO OF TIME FRAME STIFFNESS TO THE ROOF STIFFNESS. 01:15 ratio (K1 ch) w111 be used to determine the side sway force modifiers. k cls 10111912007 200`19 (Stucici) 4%x60x i4.xmcd 8 -Ee 6; DETERMINE SIDE SWAY RESISTANCE FORCE: = 0-94' S T ED 7: CALCU ATE THE ROOF DIAPHRAGM SIDE SWAY RESISTANCE FORCE: Q:= mD-R Q = 714 lbf Since not all of the total side swab force (R) is resisted by the roof diaphragm, some translation will occur at the top of the post. The distributed load that is not resisted by the roof diaphragm will apply additional moment and fiber stress to the Cost. -Mdfl = 9948 in-ibf fdf� = 78 psi Calculate tthe total mo ent (alto) and the total fiber stress i Ttj). Mia := LnD'?iF. d afi !fit t = 47062 in-Ibf ft z := -fwind 1 't = 368 psi 10il9i2001 200197 (Stucki) 40x6Ox14.xmcd 9 POST DESIGN AT EAVE WITH SHED. Calculate allowable unit stress (compression F� j. F.t = 575 psi •_ci.1 1 £c• Fe = 661 psi (Allowable compression stress including load factors; t -post bndg = 132 in (Bending lenA of posh) 1e -_ e' gcrt_ir dg = 105.6 in t?SE r'lt)iE F& KE- FE = 1799 �` Ll€10.4i Calculate Column Stability Factor, Com: F. 1 F 1' F,t F - I L' C3et n cc F'e• (r t ec = 6O is psi W,00r = 38 psf. (Total roof loading) d�_ = 8 in (Minimum unbraced dimension of post) Fw d = 1100000 psi CY = 0.91 Psno,mxmt = 10920 IDS (Aidai loading per pos€ due to roof snow load) Pdeadmst = 936 lbs (Axial loading per post due to roof stead load) Fa := Fnj• 1.6 Fb = 920 psi (Allowable bending stress per post including load factors) 1011912007 200107 {Stucki)40x;;0X14-xmcd 1 n Check Load Cases: Load Case 1: Dead Load + .75' Wind Load + .75 * Show Load tbi:= .75't fbi = 276 psi (Actual bending stress on post) . 15F}'--ilo.,t + pfteadp,,t fe 4 _ ? 90 psi (Actual compression stress per post) met Ic j It.i I `F`.) Ft, i _ t` CCFALII = 0.44 Load case 2: head Load + Wind Load fill == fiat fbi = 368 --Si (Actual bending stress on post) Pdeadtmst I� f, = 20 psi (Actual compression stress per post) A{,:t CCFALI= :— t j *. +�' '\ CCFAL12 = 0.41t Fb 1 TE Lead case 3: head Load + Snow Load fbi := 0 fbi = 0 psi (Actual bending stress on post) PSFiOWi505t + PreaGP03{ f� fC = 247 psi (Actual compression stress per post) t it } ibi t CIM -1 IS _= C + ii f` Ft,- I — _ I CCFALI3 = 0.17 F vI CCFALI = 0.44 Less than or equal to 1. ;0 thus OK 10/19/2007 200197(S-iucki)40xr-,0x'14.xmcd 11 POST EMBEDMENT FOR CONSTRAINED CONDITION: Calculate the required post depth. The concrete floor will provide a constrained condition for the post. M, = 470622 in - lbs Ph = applied lateral force (P) and distance from ground to applied lateral force (h). I I Ph 1 Serra'50 - [psf! (Assumed soil lateral bearing capacity) S3 = 1397 (calculated using a trial depth of embedment) d,,,h, = 2.7 1-1, f = Z.o ft MG U11 �Winirnurn required post embedment depth for lateral aterall loading) Veave_-vvind = 1922 lbs (Total load transferred into each gable wall) Veave-vvind-UhId. cpn,t:= - WhId.1- - Wgabl, CPO -St = 5390 lbf (This is, the uplift load on one gable wall post) opepm,s Assume a total weight of roof and wall area to be 2.0 psf. The area of the roof and wall that will tend to keep the gable wall post in the ground will be as follows: Lbl& '-ase i.lu:= 1j4jjdq.. I , E-,,,- mall = 840 lbf , 41_ P,),;t, = 1_95 lbf ','V�jjBay RWbldg t,q. Cable -wall := Hbld-.---4 2 240 lbs 560 lbf I Ar -A 150- 4.5 1 4 144) 1895 113S wtt-t := �. , + + Roof + Pasts + Post ho Askin -WaH �e V,Titat = 5692 1 b -I (Note that 'APLt,,t is greater than CP,,t- Thus OK.) 16119:2607 2604g7 (Stccki) 40x60xt4.xmcd 12 FOOTING DESIGN; Check the soil bearing capacity of the punch pads. . ftp This is the area of the footing) �lsc it = 1560 psf dia_iootlug = Z ft d-Ptv-Po,t, := 4.5 ft (Minimum embedment depth) Pfoo+,ng ooti�g gso2rdfa r., Y£,,tj,,g = 12511 lbf (End bearing capacity of footing) P ,ow = 11856 lbf Note that the end bearing capacity (Pfwvng) is greater than the snow load (Psnow). This is OK. 10119!2007 230197 '/S1uck0 4OX(30x-1.xmcd 13 SEISMIC CALCULATIONS Design per IBC 2003 S, = 6! Mapped spectral acceleration for short periods Groin above) S1 = 18.8 Mapped spectral acceleration for 1 -second period (from above) 1E = 1.0 im=portance factor W = Dead load of building R, = 7 Response modification factor (from: above) 1. Determine the Seismic Design Category a. Calculate SDs and Sc, For SDs: For S For Ss = 3.51 For Sr = C.19 F, — 1.31 = 2.05 SNI — 0.80 SMI = 0.39 NDS = { — " ALS 4P..1 — (2 )' Sp i. Su; = 0.53 S +3.2£ SM = Seismic_Design_Category = "D" 2. Determine the building parameters Building dead load weight, W: F � Tt xr" jibe t —[(jA7bi&'I'b1dg)°(pf_2)j L a e i 2-(V -r ) g i bidg'vbldg L �edg 1+14J 2 � 117= 27192 Ibf Building area, Ab-. Ab = Lb1dg' Wb1dg Ab = 2400 fie 3. Determine the shear force to be applied a. Determine the structural period; T T,,:= ll�jdg. 02 T:= T,, T = 0.28 b. Detemine tl€e Seismic Response Coefficient, Cs: Cs is calculated as: C" :— �,2 = 0.076 IE But shall not be less than: Csj := -044-SDS-IE Csi = 0.023 But need not exceed: `'tet —0.131 t �IE1 c. Detemine the Seismic Base Shear: 10/10/200; 200107 (Stucki) 40x6Gx14.xmcd 14 Cs = 0.076 v `base shear = G073 lb 4. Determine the seismic load on the building: Per IBS. for Seismic Design Category's fit, B, and ;, p =I.0- For Seismic Design Category D- E. cr shall be calculated using r n, 4a. Determine p for Seismic Design Category D, B or IF (Only if required). Determine the shortest shear panel, Lw: Lbldg — Weaveopett gs '— i I -g < Lwe,Lwg,L.J L,, = 5 fmax IE) 10 LI- max r� mss- FAb p = 1.50 E:= abase�ar E = 3109 Ibf This is the seismic load on the bulldirg 1011912007 200197 (Stucki) 40x-8ux14.xmcd 15 ANALYSIS FOR GABLE WALL: 9. Check Wird Dads: Hroof = 5 ft f Mdg _ 14 It q,= 13 psf Lbidg — 60 ft t t 'sbldg�"'-!jlci�'tle Veave vend = 1922 ibf 2. Check Seismic t=oads: Veave seismic = 1554 lbf The controlling load= ,vepve-wind" . Therefore, Viable ai as = 1922 lbf This is the lateral load that is transmitted to each gable ;mall. This load will be transmitted through the roof diaphragm to the gable walls. Normalize the load to a per foot basis. W=du- — V, a.��>1e u€ttgc LaLIeu'al; _ 384 Of The gable wall diaphragms can resist the shear loads as follows. t'pblcuali < 460 plf Then install 7/16" OSB or 1I2" CCX subsheathing with 8d nails at 3" o.c. boundary and 12" ox. field. provide 2X blocking at all panel edges. ANALYSIS FOR 'AVEWALL: 1. Check Wind Loads: Ts tom} = Ift = !- .r slxcd = 3 ft 1011912007 200197 (Stucki I4ux60x14.xrrlcd 16 q,g = 10.5 psf Wbldg = 40 11 Hroof = 5 ff Lbldg = 60 ft 'IIIDa'iT}�a ala Vs -able =_ #(f 11de ala Koof sited ..ked 14roo s}le("Xzhed # 0 75-lul)- lied + i 't]6 # E).? -q 4 Vgabie_v.ind = 1820 Ibf 2. Check Seis;nir Loads: Viable seismic :_ Vgable seismic = 1554 Ibf The controlling load = "Vgable_wind" . Therefore, Vca,, 5hcar = 1820 Ibf This is the lateral load that is transmitted to each eave wall. This load v^rill be transmitted through the roof diaphragm to the eave wails. Normalize the load to a per foot basis. _ V eave shear Veave4=311 -- I bldg — weavwPcnings veaeew ll = 30 pif The eave wall diaphragms can resist the shear loads as follows: If V.".,H < 110 falf Thea no additional sheathing is required. Next, The lateral wind load that is transmitted to the open shed eavewall will be resisted by the shed eave posts in bending. Check the bending stress in these posts. �- t �{iiT# 3laLi1 � Slte(1 care shed 5 1L} € ehed ' cfc # {l.5\ -� -I -0`v Vee shed= 224 Ibf OPIling heigh shed := 108 M F4.hedwall �Se:c�eSSalt shed ._ L-81�r� Fxa low shed == 1.6-575 in m..,,.11 -= v.,,, ,, shi°0Pcc-g-kight_shed Fx av w,l1 rh d = i 12 psi FXallow shed = 920 psi Since< �_ _ this is ok. X�V�YdIi 5h-edx$Ikn� 10/19/2007 2001971(S'Lucki)4Ox6Ox14.xmcd 17 GIRT DESIGN: The girls will simple span between posts. Calculate bending stress (fbgit,jdue to wind loading (q I and determine the required girt -size. G., qwgid = 2-84 PH Lgi.,,p,_,, = 138 in Lga-l "pan— M� = 6754 in-lbf fbi4t M"jt fb �gjt = 893 psi (Stress applied to the girt due to wind loading) Determine the allowable member -stress. I L,DF,i,,d 1.65 CR, 1-0i; CF 1.30 C,:= 1.15 E = 900 psi FbgiA 2153 > L6, psi K This is O -t PURLIN DESIGN: Assume that the purlins simply span between pairs of trusses or rafters. Determine the required purlin size. L, , - = 120 in (Bending length of purlin, I urml-span I ,vvp,,-Ii, = 6.14 ph (Distributed snow load along top edge of purlin) ?Vlp,,Ii, = 11060 in-lbf MP -lin %purlin := SPS = 1463 psi (Stress applied to the purlin due to P -lin snow and dead load) Determine the allowable member stress. LT)FSPR := 1.15 Cipmliu =130 C,:= 1.15 CfaParh, 900 psi Fbp.,jj.:= LDF.-CFjm,1m-C,-CfjPjj,,-F - - Purim FbParlm = 1547 psi > fbp,,,Ii,, This is OK 101/912007 200197 (Stucki) A t,3x6Oxl4.xmcd 18 SHED RAFTER DESIGN: Determine the required section for the shed rafters. The rafters will simple span between posts. It will be assumed that both ends are pinned, 11 er say = 138 in Shed rafter span S,,ap,,, = 31.64 Section Modulus for (1) rafter 18.E pli M- .g-,- = 43879 lb -inch Use = "double rafters (I ea side of posh}' Determine fiber stress- Qtl FbDFSSd-. Fk.fl,- := Ll-)FSROW' CF'-11�- -";.ft.r Ratio -Ft, f1,, &,. = 1387 psi Bending stress of each rafter F, -,f,, = 1500 psi Allowable bending stress Fb,,,&, = 1725 psi > Ubftd Ratio -Pb = 80 % OK 10119 2007 2,0191 (Stuck€) 4ux69xi4.xmcd 19 M. POST CORBEL BLOCK DESIGN: Determine the required number and size of rails required in the main dost corbel block. Assume full snow load and dead load on the roof. P,,,w = 11856 lbf Combined snow and dead load on corbeis Pisa 122 lbf Shear capacity for 16d nails P20a 147 lbf Shear capacity for 20d nails If 20d nails are to be used: � " aiLQOd = 35-1 number of 20d nails required in each corbel block. 9f 16d nails are to be used: ai ,116E1 = 2- nuMDer of 16d nails required in each corbel block. i0119/2-007 2 01;191 Stucki) 40x60x14.xmcd 2 SUMMARY OF RESULTS. Buildinq Dimensions Buildina i?e�odds W -,dg = 40It Midth of Building) Wind speed = ye MPH Ground snow load = 47 psf 1 -bldg _ 60 ft (Length of Building) Wind exposure- = "C" Roof snow load= 35 psf dead load = 3 psf r btdg = i4 ft (cage Height of Building)Roof — — Seismic Design Category = "El" of in (Length of cave Overhang) Rpit,h = 3 f 12 (Roof pitch! Footirtca I?eta=1S: Post Details Postdepth = 4.5 ft (Design Post Depth) D size =""VFF o 1 Jost , - dC.i,,^=2.5 ft fDesign noting Diameter', eter)jV.y Usage = 44 % (Combined stress usage ofpost) Footingusage- — 95 °jc (Stress usage of fooling) Shear Wall Details: gablerali = 384 plf (Max. shear in gable wall) vea�ec�all = 30 plf (Max. shear in eave wall) Girt Details: Purlin Details: Girt usage = 41 % (Stress usage Purlin usage = 95 % (Stress usage of roof purlin Orientation = "Cornmareia;`. call gist) — for snow loading) Corbel Bloch Nails: Nai;s,6d = 42.3 In ea. corbel Nail520d = 35.1 In ea. corbel Shed Corbel Bloch Bolts- Nbolts53_int = 1.5 Dumber of 5t8" dia. bolts required in the interior past corbel block if used. Nb ;fjs5s shed = 1.5 Number of 5I8" dia. bolts required in the shed post corbel block if used. Nbott534 int = 1.1 Number of 314" dia. bolts required in the interior post corbel block if used. NSb.h.34s1,.d = 1.1 Number of 314" dia. bolts required in the shed post corbel black if used. SPECIAL NOTE: The drawings attendant to this calculation shall not be modified by the builder unless authorized in writing by the engineer. No special inspections are required_ No structural observation by the design engineer is required.