b'YOUR TOOLKIT FOR BUILDING EXCELLENCEMembersizesandpropertiesaregiveninTable3. TABLE 3: MEMBER PROPERTIESMember ID 40x80 Building 60x80 Building 80x160 BuildingPost 5.5"x5.5" #2 SP 5.5"x5.5" #2 SP 7.5"x7.5" #2 SPTruss Top Chord 2x12 SP MSR 2x12 SP MSR (2) 2x12 SP MSR2400f-2.0E 2400f-2.0E 2400f-2.0ETruss Bottom Chord 2x12 SP MSR 2x12 SP MSR (2) 2x12 SP MSR2400f-2.0E 2400f-2.0E 2400f-2.0ETruss Webs 2x4 #1 SP 2x4 #1 SP (2) 2x4 #1 SPKnee Brace 2x6 #2 SP 2x6 #2 SP 2x6 #2 SPKnee Brace Connection (6) 0.148"x3" Nails (6) 0.148"x3" Nails (6) 0.148"x3" NailsKnee Brace Slip Member 0.369"x0.369"x6" 0.369"x0.369"x6" 0.369"x0.369"x6"E=1,400 ksi E=1,400 ksi E=1,400 ksiIn all buildings, posts and trusses are spaced 8ft o.c.modeled with lateral springs consistent with the Universal Slip modulus is calculated using Equation 8-4 in WoodMethod of the ASABE EP486.3.The water table is assumed to In all buildings, posts and trusses are spaced 8ft o.c. Slip modulus is calculated using Equation 8-4 in Wood Handbook FPL (2010). Fastener slippage is representedbe below the footer.The increase in Youngs modulus per unit Handbook FPL (2010). Fastener slippage is represented by one 0.3619 x 0.3619 x 6 long link member with2by one 0.3619 x 0.3619 x 6 long link member with elasticdepth below grade, A E , as defined in EP486.3, is 220 (lb/in )/elastic modulus, E, of 1,400,000 psi at the bottom of each knee brace. Standard procedure for lateral load analysis is modulus, E, of 1,400,000 psi at the bottom of each knee brace.in.This value includes 100% increase per EP486.3, Table 1, described in ASABE EP484.3 (2017) and is summarized as follows: Standard procedure for lateral load analysis is describedFootnote e(this is due to water table).There are 8 soil springs(1) determinethe lateral stiffness of the primary frame, (2) determine the lateral stiffness of the end walls and the in ASABE EP484.3 (2017) and is summarized as follows: spaced 6 inches apart.The first (top) and the last (bottom) roof diaphragm, (3) determine the lateral eave load at each frame, (4) distribute the lateral eave load to all (1) determinethe lateral stiffness of the primary frame,springs are located at 3 inches and 45 inches below grade, participating components of the lateral force resisting system (frame, diaphragm, end walls) and calculate eave (2) determine the lateral stiffness of the end walls andrespectively.The stiffness constant increases linearly from horizontal deflections using equations and tables given in EP484.3 or using the DAFI computer program (available the roof diaphragm, (3) determine the lateral eave load7920 lb/in at the first spring to 118,800 lb/in at the last spring. free from NFBA website).Similar analysis can be performed using General Solution for Post-Frame Roof Diaphragm Deflections (Patrick M. McGuire, 1998).In this paper, the lateral loads are distributed using the method developed by at each frame, (4) distribute the lateral eave load to all McGuire and validated using DAFI. participating components of the lateral force resisting system(frame,diaphragm,endwalls)andcalculate Wind load on the building is calculated using the envelope procedure given in ASCE 7-16, Chapter 28, using 115 eave horizontal deflections using equations and tables mph wind speed, wind Exposure C, internal pressure coefficient +/- 0.18 (enclosed building).Two wind load cases are considered in this study (Figure 3). The total diaphragm sides way restraining force, Q, which is determined by given in EP484.3 or using the DAFI computer program (available free from NFBA website).Similar analysis canp,aand q p,b . structural analysis per EP484.3, is applied to the top chord of truss using continuous uniform loads qbe performed using General Solution for Post-Frame The minimum ASCE 7 load requirements of 16 psf and 8 psf pressures on wall and roof, respectively, are not Roof Diaphragm Deflections (Patrick M. McGuire, 1998). considered.A 4 psf dead load and 20 psf snow (live) load is applied to the top chord of the truss and 1 psf dead load In this paper, the lateral loads are distributed using the is applied to the bottom chord. method developed by McGuire and validated using DAFI. CASE 1: GC PI= +0.18 CASE 2: GC= - 0.18 The foundation is a non-constrained shallow post foundation modeled with lateral springs consistent with thePIFIGURE 3. Wind load cases; load effect on the main wind force resisting Universal Method of the ASABE EP486.3.The water table is assumed to be below the footer.The increase in Wind load on the building is calculated using the envelopesystem in Case 1 and Case 2 is greater when roof wind pressures are Youngs modulus per unit depth below grade, A E , as defined in EP486.3, is 220 (lb/in 2 )/in.This value includes 100% procedure given in ASCE 7-16, Chapter 28, using 115 mphignored (ASCE 7-16, Figure 28.3.1, Footnote 6), q p,aand q p,bare uniform increase per EP486.3, Table 1, Footnote e.(this is due to water table).There are 8 soil springs spaced 6 inches wind speed, wind Exposure C, internal pressure coefficientin-plane diaphragm forces apart.The first (top) and the last (bottom) springs are located at 3 inches and 45 inches below grade, respectively.+/- 0.18 (enclosed building).Two wind load cases areA percentage of the lateral wind load is transferred into The stiffness constant increases linearly from 7920 lb/in at the first spring to 118,800 lb/in at the last spring. considered in this study (Figure 3). The total diaphragmthe frame and the roof diaphragm at the top of the post sides way restraining force, Q, which is determined by(eave load, R), and the remainder is transferred into the structural analysis per EP484.3, is applied to the top chordsoil at the bottom of the post.Clause 6.3 of EP484.3 uses of truss using continuous uniform loads q p,aand q p,b . post fixity factor ratios to describe the ratio of the total TheminimumASCE7loadrequirementsof16psfwall load transferred up into the frame and the diaphragm. and 8 psf pressures on wall and roof, respectively, areThe prescribed post fixity factors are not used in this not considered.A 4 psf dead load and 20 psf snowanalysis and should not be used in post frame buildings (live)loadisappliedtothetopchordofthetrusswith knee braces.Instead, the eave load, R, is determined and 1 psf dead load is applied to the bottom chord.by installing a horizontal restraint at the eave line of the structural model as described in EP484.3, Clause 6.2.The The foundation is a non-constrained shallow post foundationeave load is equal to the reaction at the horizontal restraint.continued on page 20 FRAME BUILDER - MAY2023 / 19'