"ASCE798W" --- ASCE 7-98 CODE WIND ANALYSIS PROGRAM Program Description: "ASCE798W" is a spreadsheet program written in MS-Excel for the purpose of wind loading analysis for buildings and structures per the ASCE 7-98 Code. Specifically, wind pressure coefficients and related and required parameters are selected or calculated in order to compute the net design wind pressures. This program is a workbook consisting of eight (8) worksheets, described as follows:
Worksheet Name
Description
Doc Simplified MWFRS (Low-Rise) MW FRS (Any Ht.) W all C&C Roof C&C Stacks & Tanks W ind Map
This documentation sheet Analysis using simplified method method for low-rise buildings with h <= 30‟ Main Wind-Force Resisting System for low-rise buildings with h <= 60‟ Main W ind-Force Resisting System for buildings of any height Analysis of wall Components and Cladding Analysis of roof Components and Cladding Analysis of cantilevered chimneys, stacks, and vertical tanks Basic wind speed map (Figure 6-1 of ASCE 7-98 Code)
Program Assumptions and Limitations: 1. This program assumes only enclosed or partially enclosed buildings. Open buildings are NOT considered. 2. Worksheet for Simplified analysis is applicable for buildings meeting the criteria of Section 6.4.1. 3. In the worksheet for Simplified analysis, the design MWFRS wind load is calculated for each direction. This design load is assumed equal to 1/2 of the total load, as 1/2 is assumed to be taken at roof level and the other 1/2 is taken at the base of the building. 4. Worksheet for MWFRS (Low-Rise) is applicable for low-rise buildings as defined in Section 6.2. 5. Worksheets for MWFRS (Any Ht.), Wall C&C, and Roof C&C are applicable for buildings with mean roof heights of up to 500 feet. 6. Worksheet for Stacks & Tanks is applicable for cantilevered structures up to 600 feet tall. 7. Worksheets for W all C&C and Roof C&C are applicable for flat roof buildings, gable roof buildings with roof angles <= 45 degrees, and monoslope roof buildings with roof angles <= 3 degrees. 8. Worksheets for MWFRS (Any Ht.) and for Stacks Stacks & Tanks can handle “rigid” as well as “flexible” buildings and structures. For “rigid” buildings or structures, this program uses the smaller value of either 0.85 0.85 or the calculated value from Section 6.5.8.1 of the Code for the gust effect factor, 'G'. For “flexible” buildings or structures, this program calculates the gust effect factor, „Gf‟, per Section 6.5.8 of the Code based on the assumed formula for the fundamental period of vibration from Section 9.5.3.3 of the Code. 9. This program uses the equations listed listed in the reference, “Guide to the Use of the Wind Load Provisions of ASCE 7-98” for determining the external external wind pressure coefficients, „GCp‟, used in the Wall C&C and Roof C&C worksheets. 10. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc. (Note: presence of a “comment “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell. Merely move the mouse pointer to the desired cell to view the contents of that particular "comment box".)
"ASCE798W.xls" Program Version 2.9
WIND LOADING ANALYSIS ANALYSIS - Main Wind-Force Resisting System Job Name: Job Number:
Per ASCE 7-98 Code for Low-Rise Buildings with h <= 30' and Roof < 10o Using Method 1: Simplified Procedure (Section 6.4) Subject: Originator: Checker:
Input Data: Wind Speed, V = 130 mph (Wind Map, Fig. 6-1) Bldg. Classification = (Table 1-1) II Exposure Category = C (Sect. 6.5.6) (Do not use Exp. "A") Ridge Height, hr = 15.00 ft. (hr >= he) Eave Height, he = 15.00 ft. (he <= hr) Building Width = 30.00 ft. (Normal to Building Ridge) Building Length = 60.00 ft. (Parallel to Building Ridge) Roof Type = Monoslope (Gable or Monoslope) Enclosed? (Y/N) Y (Sect. 6.2 & Table 6-7) MWFRS Trib. Area = 1800.00 ft.^2 Roof C&C Name = Joist (Purlin, Joist, Decking, or Fastener) Roof C&C Area = 300.00 ft.^2 (for Component/Cladding) hr Wall C&C Name = Wall (Girt, Siding, Wall, or Fastener) Wall C&C Area = 75.00 ft.^2 (for Component/Cladding) Resulting Parameters and Net Design Pressures:
Length Leng th
Width
Plan
q<10o h<=30'
he
Width
Elevation Roof Angle, q = Mean Roof Roof Ht., h =
0.00 15.00
MWFRS Net Pressures res Location p (psf) Roof -36.96 Walls 40.60
deg. ft. (h = he for q < 10 deg.) Design MWFRS Load SP (kips) SP (kips) (W idth) (Length) 9 .1 4 18.27
Components & Cladding Net Pressures Location Zone +p (psf) -p (psf) 1 14. 0 0 -39.20 2 14. 0 0 -46.20 Roof Joist 3 14. 0 0 -46.20 Wall 4 37. 4 9 -41.61 5 37. 4 9 -46.90 Notes:
1. Design wind pressures are net pressures (sum of external and internal pressures). 2. Wall net pressure for MWFRS is total for both windward and leeward walls. 3. (+) and (-) signs signify wind pressures acting t oward & away from respective surfaces. 4. Net pressures taken from Tables 6-2, 6-3A and 6-3B and include the following "multipliers": Exposure Factor = 1.40 Area Reduction Factor = 0.80 Importance Factor, I = 1.00 5. Wall & Roof End Zone Widths for Components & Cladding: a = 3.00 ft. 6. Minimum wind load for MWFRS and C&C shall not be less than 10 psf. 7. References: a. ASCE 7-98, "Minimum Design Loads for Buildings and Other Structures". b. "Guide to the Use of the Wind Load Provisions of ASCE 7-98" by: Kishor C. Mehta and Dale C. Perry (2002).
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"ASCE798W.xls" Program Version 2.9
WIND LOADING ANALYSIS - Main Wind-Force Resisting System Per ASCE 7-98 Code for Enclosed or Partially Enclosed Buildings Using Method 2: Analytical Procedure (Section 6.5) for Low-Rise Buildings Job Name: Subject: Job Number: Originator: Checker: Input Data: Wind Speed, V = Bldg. Classification = Exposure Category = Ridge Height, hr = Eave Height, he = Building Width = Building Length = Roof Type = Topo. Factor, Kzt = Direct. Factor, Kd = Enclosed? (Y/N)
90 II
C 53.33 20.00 200.00 250.00 Gable
1.00 0.85 Y
mph (Wind Map, Fig. 6-1) (Table 1-1) (Sect. 6.5.6) ft. (hr >= he) ft. (he <= hr) ft. (Normal to Building Ridge) ft. (Parallel to Building Ridge) (Gable or Monoslope) (Sect. 6.5.7) (Table 6-6) (Sect. 6.2 & Table 6-7)
Wind
B
L
Plan
hr
qo h<=60'
Resulting Parameters and Coefficients: Roof Angle, q = Mean Roof Ht., h =
18.43 36.67
deg. ft. (h = (hr+he)/2, for angle >10 deg.)
Check Criteria for a Low-Rise Building: 1. Is h <= 60' ? Yes, O.K.
2. Is h <= Lesser of L or B?
he
L
Elevation
Yes, O.K.
External Pressure Coeff's., GCpf (Fig. 6-4): (For values, see following wind load tabulations.) Positive & Negative Internal Pressure Coefficients, GCpi (Table 6-7): +GCpi Coef. = 0.18 (positive internal pressure) -GCpi Coef. = -0.18 (negative internal pressure) If h < 15 then: Kh = 2.01*(15/zg)^(2/ a) (Table 6-5, Case 1b) If h >= 15 then: Kh = 2.01*(z/zg)^(2/ a) (Table 6-5, Case 1b) a= 9.50 (Table 6-4) zg = 900 (Table 6-4) Kh = 1.02 (Kh = Kz evaluated at z = h) I= 1.00 (Table 6-1) (Importance factor) Velocity Pressure: qz = 0.00256*Kz*Kzt*Kd*V^2*I (Sect. 6.5.10, Eq. 6-13) qh = 18.06 psf qh = 0.00256*Kh*Kzt*Kd*V^2*I (qz evaluated at z = h) Design Net External Wind Pressures (Sect. 6.5.12.2.2): p = qh*[(GCpf) - (+/-GCpi)] (psf, Eq. 6-16) Wall and Roof End Zone Widths 'a' and '2*a' (Fig. 6-4): a= 14.67 ft. 2*a = 29.33 ft.
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"ASCE798W.xls" Program Version 2.9 MWFRS Wind Load Tabulation for Case 'A' Surface GCpf p = Net Pressures (psf) (w/ +GCpi) (w/ -GCpi) Zone 1 0.52 6.08 12.58 Zone 2 -0.69 -15.71 -9.21 Zone 3 -0.47 -11.71 -5.21 Zone 4 -0.42 -10.75 -4.25 Zone 1E 0.78 10.84 17.34 Zone 2E -1.07 -22.57 -16.07 Zone 3E -0.67 -15.41 -8.91 Zone 4E -0.62 -14.41 -7.91
Surface Zone 1 Zone 2 Zone 3 Zone 4 Zone 1E Zone 2E Zone 3E Zone 4E
Case 'A' Rotated (Corner II) *GCpf p = Net Pressures (psf) (w/ +GCpi) (w/ -GCpi) 0.40 3.97 10.47 -0.69 -15.71 -9.21 -0.37 -9.93 -3.43 -0.29 -8.49 -1.99 0.61 7.77 14.27 -1.07 -22.57 -16.07 -0.53 -12.82 -6.32 -0.43 -11.02 -4.51
*Note: Use roof angle q = 0 degrees for Case 'A' rotated. For Case 'A' when GCpf is neg. in Zone 2: For Case 'A' rot. when GCpf is neg. in Zone 2: Zone 2 distance = 91.66 ft. Zone 2 distance = 91.66 ft. Remainder of roof Zone 2 to have roof Zone 3 pressures. MWFRS Wind Load Tabulation for Case 'B' Surface GCpf p = Net Pressure (psf) (w/ +GCpi) (w/ -GCpi) Zone 1 -0.45 -11.38 -4.88 Zone 2 -0.69 -15.71 -9.21 Zone 3 -0.37 -9.93 -3.43 Zone 4 -0.45 -11.38 -4.88 Zone 5 0.40 3.97 10.47 Zone 6 -0.29 -8.49 -1.99 Zone 1E -0.48 -11.92 -5.42 Zone 2E -1.07 -22.57 -16.07 Zone 3E -0.53 -12.82 -6.32 Zone 4E -0.48 -11.92 -5.42 Zone 5E 0.61 7.77 14.27 Zone 6E -0.43 -11.02 -4.51
Surface Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zone 1E Zone 2E Zone 3E Zone 4E Zone 5E Zone 6E
Case 'B' Rotated (Corner II) GCpf p = Net Pressure (psf) (w/ +GCpi) (w/ -GCpi) -0.45 -11.38 -4.88 -0.69 -15.71 -9.21 -0.37 -9.93 -3.43 -0.45 -11.38 -4.88 0.40 3.97 10.47 -0.29 -8.49 -1.99 -0.48 -11.92 -5.42 -1.07 -22.57 -16.07 -0.53 -12.82 -6.32 -0.48 -11.92 -5.42 0.61 7.77 14.27 -0.43 -11.02 -4.51
Notes: 1. For Case 'A', Case 'A' Rotated (90 deg.), Case 'B', and Case 'B' Rotated (90 deg.): Zone 1 is windward wall for interior zone. Zone 1E is windward wall for end zone. Zone 2 is windward roof for interior zone. Zone 2E is windward roof for end zone. Zone 3 is leeward roof for interior zone. Zone 3E is leeward roof for end zone. Zone 4 is leeward wall for interior zone. Zone 4E is leeward wall for end zone. Zone 5 is sidewall for interior zone. Zone 5E is sidewall for end zone. Zone 6 is sidewall for interior zone. Zone 6E is sidewall for end zone. 2. (+) and (-) signs signify wind pressures acting toward & away from respective surfaces. 3. Per Code Section 6.1.4.1, the minimum wind load for MWFRS shall not be less than 10 psf. 4. References : a. ASCE 7-98, "Minimum Design Loads for Buildings and Other Structures". b. "Guide to the Use of the Wind Load Provisions of ASCE 7-98" by: Kishor C. Mehta and Dale C. Perry (2002).
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"ASCE798W.xls" Program Version 2.9
MWFRS Zones and Load Cases for Low-Rise Buildings:
FIGURE C6-2. Application of Load Cases for Two Windward Corners
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"ASCE798W.xls" Program Version 2.9
WIND LOADING ANALYSIS - Main Wind-Force Resisting System Per ASCE 7-98 Code for Enclosed or Partially Enclosed Buildings Using Method 2: Analytical Procedure (Section 6.5) for Buildings of Any Height Job Name: Subject: Job Number: Originator: Checker: Input Data: Wind Direction = Wind Speed, V = Bldg. Classification = Exposure Category = Ridge Height, hr = Eave Height, he = Building Width = Building Length = Roof Type = Topo. Factor, Kzt = Direct. Factor, Kd = Enclosed? (Y/N) Damping Ratio, b = Period Coef., Ct =
Normal 120
(Normal or Parallel to building ridge) mph (Wind Map, Fig. 6-1) Wind (Table 1-1) II B (Sect. 6.5.6) 157.00 ft. (hr >= he) 157.00 ft. (he <= hr) 100.00 ft. (Normal to Building Ridge) 200.00 ft. (Parallel to Building Ridge) Monoslope (Gable or Monoslope) 1.00 (Sect. 6.5.7) 0.85 (Table 6-6) Y (Sect. 6.2 & Table 6-7) 0.030 (Suggested Range = 0.010-0.070) 0.0200 (Suggested Range = 0.020-0.035) hr
B
L
Plan
qo h
(Assume: T = Ct*h^(3/4) , and f = 1/T)
Resulting Parameters and Coefficients: Roof Angle, q = Mean Roof Ht., h = Windward Wall Cp = Leeward Wall Cp = Side Walls Cp = Roof Cp (zone #1) = Roof Cp (zone #2) = Roof Cp (zone #3) = Roof Cp (zone #4) = +GCpi Coef. = -GCpi Coef. =
0.00 157.00 0.80 -0.50 -0.70 -1.04 -0.70 N.A. N.A. 0.18 -0.18
he
L
deg. ft. (h = he, for roof angle <=10 deg.) (Fig. 6-3) (Fig. 6-3) (Fig. 6-3) (Fig. 6-3) (zone #1 for 0 to h/2) (Fig. 6-3) (zone #2 for h/2 to h) (Fig. 6-3) (zone #3 for h to 2*h) (Fig. 6-3) (zone #4 for > 2*h) (Table 6-7) (positive internal pressure) (Table 6-7) (negative internal pressure)
Elevation L = 100 ft. B = 200 ft.
If z <= 15 then: Kz = 2.01*(15/zg)^(2/ a) , If z > 15 then: Kz = 2.01*(z/zg)^(2/ a) (Table 6-5, Case 2a) a= 7.00 zg = 1200 (Table 6-4) Kh = 1.12 (Kh = Kz evaluated at z = h) I= 1.00 (Table 6-1) (Importance factor) Velocity Pressure: qz = 0.00256*Kz*Kzt*Kd*V^2*I (Sect. 6.5.10, Eq. 6-13) qh = 35.23 psf qh = 0.00256*Kh*Kzt*Kd*V^2*I (qz evaluated at z = h) Ratio h/L = 1.570 freq., f = 1.127 hz. (f >= 1, Rigid structure) Gust Factor, G = 0.818 (Sect. 6.5.8) Design Net External Wind Pressures (Sect. 6.5.12.2): p = qz*G*Cp - qi*(+/-GCpi) for windward wall (psf), where: qi =qh (Eq. 6-15, Sect. 6.5.12.2.1) p = qh*G*Cp - qi*(+/-GCpi) for leeward wall, sidewalls, and roof (psf), where: qi = qh (Sect. 6.5.12.2.1)
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"ASCE798W.xls" Program Version 2.9 Normal to Ridge Wind Load Tabulation for MWFRS - Buildings of Any Height z Kz qz Cp p = Net Design Press. (psf) (ft.) (psf) (w/ +GCpi) (w/ -GCpi) Windward Wall 0 0.57 18.01 0.80 5.45 18.13 15.00 0.57 18.01 0.80 5.45 18.13 20.00 0.62 19.55 0.80 6.46 19.14 25.00 0.67 20.84 0.80 7.30 19.98 30.00 0.70 21.95 0.80 8.03 20.71 35.00 0.73 22.94 0.80 8.68 21.36 40.00 0.76 23.83 0.80 9.26 21.94 45.00 0.79 24.65 0.80 9.80 22.48 50.00 0.81 25.40 0.80 10.29 22.97 55.00 0.83 26.10 0.80 10.75 23.43 60.00 0.85 26.76 0.80 11.18 23.86 70.00 0.89 27.97 0.80 11.97 24.65 80.00 0.93 29.05 0.80 12.68 25.36 90.00 0.96 30.05 0.80 13.33 26.01 100.00 0.99 30.97 0.80 13.93 26.61 120.00 1.04 32.62 0.80 15.01 27.70 140.00 1.09 34.09 0.80 15.98 28.66 For z = hr: 157.00 1.12 35.23 0.80 16.72 29.40 Surface
For z = he: For z = h: Leeward Wall Side Walls Roof (zone #1) Roof (zone #2)
157.00 157.00 All All -
1.12 1.12 -
35.23 35.23 -
0.80 0.80 -0.50 -0.70 -1.04 -0.70
16.72 16.72 -20.75 -26.52 -36.32 -26.52
29.40 29.40 -8.07 -13.84 -23.64 -13.84
Notes: 1. (+) and (-) signs signify wind pressures acting toward & away from respective surfaces. 2. Per Code Section 6.1.4.1, the minimum wind load for MW FRS shall not be less than 10 psf. 3. References : a. ASCE 7-98, "Minimum Design Loads for Buildings and Other Structures". b. "Guide to the Use of the Wind Load Provisions of ASCE 7-98" by: Kishor C. Mehta and Dale C. Perry (2002). 4. Roof zone #1 is applied for horizontal distance of 0 to h/2 from windward edge. 5. Roof zone #2 is applied for horizontal distance of h/2 to h from windward edge.
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"ASCE798W.xls" Program Version 2.9
Determination of Gust Effect Factor, G: Is Building Flexible?
No
f >=1 Hz.
1: Simplified Method for Rigid Building G= 0.850 Parameters Used in Both Item #2 and Item #3 Calculations (from Table 6-4): a^ = 0.143 b^ = 0.84 a(bar) = 0.250 b(bar) = 0.45 c= 0.30 l= 320 ft. e(bar) = 0.333 z(min) = 30 ft. Calculated Parameters Used in Both Rigid and/or Flexible Building Calculations: z(bar) = 94.20 = 0.6*h , but not < z(min) , ft. Iz(bar) = 0.252 = c*(33/z(bar))^(1/6) , Eq. 6-3 = l*(z(bar)/33)^( e(bar)) , Eq. 6-5 Lz(bar) = 453.94 gq = 3.4 (3.4, per Sect. 6.5.8.1) gv = 3.4 (3.4, per Sect. 6.5.8.1) gr = 4.218 = (2*(LN(3600*f)))^(1/2)+0.577/(2*LN(3600*f))^(1/2) , Eq. 6-7 Q= 0.805 = (1/(1+0.63*((B+h)/Lz(bar))^0.63))^(1/2) , Eq. 6-4 2: Calculation of G for Rigid Building G= 0.818 = 0.925*((1+1.7*gq*Iz(bar)*Q)/ (1+1.7*gv*Iz(bar))) , Eq. 6-2 3: Calculation of Gf for Flexible Building b= 0.030 Damping Ratio Ct = 0.020 Period Coefficient T= 0.887 = Ct*h^(3/4) , sec. (Period) f= 1.127 = 1/T , Hz. (Natural Frequency) V(fps) = N.A. = V(mph)*(88/60) , ft./sec. = b(bar)*(z(bar)/33)^( a(bar))*V*(88/60) , ft./sec. , Eq. 6-12 V(bar,zbar) = N.A. N1 = N.A. = f*Lz(bar)/(V(bar,zbar)) , Eq. 6-10 Rn = N.A. = 7.47*N1/(1+10.3*N1)^(5/3) , Eq. 6-9 hh = N.A. = 4.6*f*h/(V(bar,zbar)) = (1/ hh)-1/(2*hh^2)*(1-e^(-2*hh)) for hh > 0, or = 1 for hh = 0 ,Eq. 6-11 Rh = N.A. hB = N.A. = 4.6*f*B/(V(bar,zbar)) = (1/ hB)-1/(2*hB^2)*(1-e^(-2*hB)) for hB > 0, or = 1 for hB = 0,Eq. 6-11 RB = N.A. hL = N.A. = 15.4*f*L/(V(bar,zbar)) = (1/ hL)-1/(2*hL^2)*(1-e^(-2*hL)) for hL > 0, or = 1 for hL = 0 ,Eq. 6-11 RL = N.A. = ((1/ b)*Rn*Rh*RB*(0.53+0.47*RL))^(1/2) , Eq. 6-8 R= N.A. Gf = N.A. = 0.925*(1+1.7*Iz(bar)*(gq^2*Q^2+gr^2*R^2)^(1/2))/(1+1.7*gv*Iz(bar)) , Use: G = 0.818 Eq. 6-6
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"ASCE798W.xls" Program Version 2.9
Wind Pressure Combinations for Full and Partial Loading of MWFRS for Buildings with h > 60 ft.
Case 1: Full design wind pressures acting on the projected area perpendicular to each principal axis of the building considered separately. Case 2: Wind pressure as defined in Case 1, but with a 25% reduction in pressure acting on 50% of the projected area bounded by the extreme projected edge of the building. Case 3: Wind pressure as defined in Case 1, but considered to act simultaneously at 75% of the specified value. Case 4: Wind pressure as defined in Case 3, but with a 25% reduction of these pressures acting on 50% of the projected area bounded by the extreme projected edge of the building. Notes: 1. Design wind pressures for windward (Pw) and leeward (PL) faces are obtained from provisions for buildings with a mean roof height, h > 60 ft. (per Sect. 6.5.12). 2. Above diagrams show plan view of building. 3. Pw = Windward face design pressure , PL = Leeward face design pressure.
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"ASCE798W.xls" Program Version 2.9
WIND LOADING ANALYSIS - Wall Components and Cladding Job Name: Job Number:
Per ASCE 7-98 Code for Buildings of Any Height Using Method 2: Analytical Procedure (Section 6.5) Subject: Originator:
Checker:
Input Data: Wind Speed, V = Bldg. Classification = Exposure Category = Ridge Height, hr = Eave Height, he = Building Width = Building Length = Roof Type = Topo. Factor, Kzt = Direct. Factor, Kd = Enclosed? (Y/N) Component Name = Effective Area, Ae =
90 II
C 53.33 20.00 200.00 250.00 Gable
1.00 0.85 Y Girt 208
mph (Wind Map, Fig. 6-1) (Table 1-1) (Sect. 6.5.6) ft. (hr >= he) ft. (he <= hr) ft. (Normal to Building Ridge) ft. (Parallel to Building Ridge) (Gable or Monoslope) (Sect. 6.5.7) (Table 6-6) (Sect. 6.2 & Table 6-7) (Girt, Siding, Wall, or Fastener) ft.^2 (Area Tributary to C&C)
B
L
Plan
hr
qo h
he
L
Resulting Parameters and Coefficients:
Elevation Roof Angle, q = Mean Roof Ht., h =
18.43 36.67
deg. ft. (h = (hr+he)/2, for roof angle >10 deg.)
Wall External Pressure Coefficients, GCp: GCp Zone 4 Pos. = 0.77 (Fig. 6-5A) GCp Zone 5 Pos. = 0.77 (Fig. 6-5A) GCp Zone 4 Neg. = -0.87 (Fig. 6-5A) GCp Zone 5 Neg. = -0.93 (Fig. 6-5A) Positive & Negative Internal Pressure Coefficients, GCpi (Table 6-7): +GCpi Coef. = 0.18 (positive internal pressure) -GCpi Coef. = -0.18 (negative internal pressure) If z <= 15 then: Kz = 2.01*(15/zg)^(2/ a) , If z > 15 then: Kz = 2.01*(z/zg)^(2/ a) (Table 6-5, Case 1a) a= 9.50 (Table 6-4) zg = 900 (Table 6-4) Kh = 1.02 (Kh = Kz evaluated at z = h) I= 1.00 (Table 6-1)(Importance factor) Velocity Pressure: qz = 0.00256*Kz*Kzt*Kd*V^2*I (Sect. 6.5.10, Eq. 6-13) qh = 18.06 psf qh = 0.00256*Kh*Kzt*Kd*V^2*I (qz evaluated at z = h) Design Net External Wind Pressures (Sect. 6.5.12.4): For h <= 60 ft.: p = qh*((GCp) - (+/-GCpi)) (psf) For h > 60 ft.: p = q*(GCp) - qi*(+/-GCpi) (psf) where: q = qz for windward walls, q = qh for leeward walls and side walls qi = qh for all walls (conservatively assumed per Sect. 6.5.12.4.2)
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"ASCE798W.xls" Program Version 2.9
For z = hr:
Wind Load Tabulation for Wall Components & Cladding z Kh qh p = Net Design Pressures (psf) (ft.) (psf) Zone 4 (+) Zone 4 (-) Zone 5 (+) Zone 5 (-) 0 1.02 18.06 17.11 -18.91 17.11 -20.13 15.00 1.02 18.06 17.11 -18.91 17.11 -20.13 20.00 1.02 18.06 17.11 -18.91 17.11 -20.13 25.00 1.02 18.06 17.11 -18.91 17.11 -20.13 30.00 1.02 18.06 17.11 -18.91 17.11 -20.13 35.00 1.02 18.06 17.11 -18.91 17.11 -20.13 40.00 1.02 18.06 17.11 -18.91 17.11 -20.13 45.00 1.02 18.06 17.11 -18.91 17.11 -20.13 50.00 1.02 18.06 17.11 -18.91 17.11 -20.13 53.33 1.02 18.06 17.11 -18.91 17.11 -20.13
For z = he: For z = h:
20.00 36.67
Component Girt
1.02 1.02
18.06 18.06
17.11 17.11
-18.91 -18.91
17.11 17.11
-20.13 -20.13
Notes: 1. (+) and (-) signs signify wind pressures acting toward & away from respective surfaces. 2. Width of Zone 5 (end zones), 'a' = 14.67 ft. 3. Per Code Section 6.1.4.2, the minimum wind load for C&C shall not be less than 10 psf. 4. References : a. ASCE 7-98, "Minimum Design Loads for Buildings and Other Structures". b. "Guide to the Use of the Wind Load Provisions of ASCE 7-98" by: Kishor C. Mehta and Dale C. Perry (2002).
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"ASCE798W.xls" Program Version 2.9
Wall Components and Cladding:
Wall Zones for Buildings with h <= 60 ft.
Wall Zones for Buildings with h > 60 ft.
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"ASCE798W.xls" Program Version 2.9
WIND LOADING ANALYSIS - Roof Components and Cladding o
Per ASCE 7-98 Code for Bldgs. of Any Height with Gable Roof <= 45 or Monoslope Roof Using Method 2: Analytical Procedure (Section 6.5) Job Name: Subject: Job Number: Originator: Checker:
<= 3
o
Input Data: Wind Speed, V = Bldg. Classification = Exposure Category = Ridge Height, hr = Eave Height, he = Building Width = Building Length = Roof Type = Topo. Factor, Kzt = Direct. Factor, Kd = Enclosed? (Y/N) Component Name = Effective Area, Ae = Overhangs? (Y/N)
90 II
C 53.33 20.00 200.00 250.00 Gable
1.00 0.85 Y Joist 208 N
mph (Wind Map, Fig. 6-1) (Table 1-1) (Sect. 6.5.6) ft. (hr >= he) ft. (he <= hr) ft. (Normal to Building Ridge) ft. (Parallel to Building Ridge) (Gable or Monoslope) (Sect. 6.5.7) (Table 6-6) (Sect. 6.2 & Table 6-7) (Purlin, Joist, Decking, or Fastener) ft.^2 (Area Tributary to C&C) (if used, overhangs on all sides)
B
L
Plan
hr
qo h
he
L
Resulting Parameters and Coefficients: Roof Angle, q = Mean Roof Ht., h =
18.43 36.67
Elevation
deg. ft. (h = (hr+he)/2, for roof angle >10 deg.)
Roof External Pressure Coefficients, GCp: GCp Zone 1-3 Pos. = 0.30 (Fig. 6-5B) GCp Zone 1 Neg. = -0.80 (Fig. 6-5B) GCp Zone 2 Neg. = -1.40 (Fig. 6-5B) GCp Zone 3 Neg. = -1.40 (Fig. 6-5B) Positive & Negative Internal Pressure Coefficients, GCpi (Table 6-7): +GCpi Coef. = 0.18 (positive internal pressure) -GCpi Coef. = -0.18 (negative internal pressure) If z <= 15 then: Kz = 2.01*(15/zg)^(2/ a) , If z > 15 then: Kz = 2.01*(z/zg)^(2/ a) (Table 6-5, Case 1a) a= 9.50 zg = 900 (Table 6-4) Kh = 1.02 (Kh = Kz evaluated at z = h) I= 1.00 (Table 6-1)(Importance factor) Velocity Pressure: qz = 0.00256*Kz*Kzt*Kd*V^2*I (Sect. 6.5.10, Eq. 6-13) qh = 18.06 psf qh = 0.00256*Kh*Kzt*Kd*V^2*I (qz evaluated at z = h) Design Net External Wind Pressures (Sect. 6.5.12.4): For h <= 60 ft.: p = qh*((GCp) - (+/-GCpi)) (psf) For h > 60 ft.: p = q*(GCp) - qi*(+/-GCpi) (psf) where: q = qh for roof qi = qh for roof (conservatively assumed per Sect. 6.5.12.4.2)
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"ASCE798W.xls" Program Version 2.9
For z = hr:
Wind Load Tabulation for Roof Components & Cladding z Kh qh p = Net Design Pressures (psf) (ft.) (psf) Zone 1,2,3 (+) Zone 1 (-) Zone 2 (-) Zone 3 (-) 0 1.02 18.06 8.67 -17.70 -28.53 -28.53 15.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 20.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 25.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 30.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 35.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 40.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 45.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 50.00 1.02 18.06 8.67 -17.70 -28.53 -28.53 53.33 1.02 18.06 8.67 -17.70 -28.53 -28.53
For z = he: For z = h:
20.00 36.67
Component Joist
1.02 1.02
18.06 18.06
8.67 8.67
-17.70 -17.70
-28.53 -28.53
-28.53 -28.53
Notes: 1. (+) and (-) signs signify wind pressures acting toward & away from respective surfaces. 2. Width of Zone 2 (edge), 'a' = 14.67 ft. 3. Width of Zone 3 (corner), 'a' = 14.67 ft. 4. For monoslope roofs with q <= 3 degrees, use Fig. 6-5B for 'GCp' values with 'qh'. 5. For buildings with h > 60' and q > 10 degrees, use Fig. 6-5B for 'GCpi' values with 'qh'. 6. For all buildings with overhangs, use Fig. 6-5B for 'GCp' values per Sect. 6.5.11.4.2. 7. If a parapet >= 3' in height is provided around perimeter of roof with q <= 10 degrees, Zone 3 shall be treated as Zone 2. 8. Per Code Section 6.1.4.2, the minimum wind load for C&C shall not be less than 10 psf. 9. References : a. ASCE 7-98, "Minimum Design Loads for Buildings and Other Structures". b. "Guide to the Use of the Wind Load Provisions of ASCE 7-98" by: Kishor C. Mehta and Dale C. Perry (2002).
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"ASCE798W.xls" Program Version 2.9
Roof Components and Cladding:
Roof Zones for Buildings with h <= 60 ft. o o (for Gable Roofs <= 45 and Monoslope Roofs <= 3 )
Roof Zones for Buildings with h > 60 ft. o o (for Gable Roofs <= 10 and Monoslope Roofs <= 3 )
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"ASCE798W.xls" Program Version 2.9
WIND LOADING ANALYSIS - Chimneys, Stacks, and Vertical Tanks Per ASCE 7-98 Code for Cantilevered Structures Classified as Other Structures Job Name: Job Number:
Subject: Originator:
Input Data: V= Class. = Exposure = Kzt = h= Hb = D= Shape? b= Ct = Kd =
Checker: D
90
mph (Design Wind Speed from Fig. 6-1) (Structure Classification from Table 1-1) II B (Exposure Category from Sect. 6.5.6) Wind h 1.00 (Topographic Factor from Sect. 6.5.7) 80.00 ft. (Height of Stack/Tank itself) 50.00 ft. (Ht. of Stack/Tank Base Above Ground) 3.00 ft. (Diameter or Width of Surface Normal to Wind) Hb >= 0 Ground Round (Round, Hexagonal, or Square) Elevation 0.010 (Damping Ratio = 0.010-0.070) 0.0412 (Period Coefficient = 0.020-0.035) 0.95 (Direct. Factor, Table 6-6) Wind Load Tabulation for Stack / Tank z Kz qz p=qz*G*Cf F=qz*G*Cf*D (ft.) (psf) (psf) (lb/ft) Resulting Parameters and Coefficients: 50.00 0.81 15.97 12.54 37.61 55.00 0.83 16.41 12.88 38.65 If z < 15 then: Kz = 2.01*(15/zg)^(2/ a) 60.00 0.85 16.82 13.21 39.62 If z >= 15 then: Kz = 2.01*(z/zg)^(2/ a) 65.00 0.87 17.21 13.51 40.54 a= 7.00 (Table 6-4) 70.00 0.89 17.58 13.80 41.41 zg = 1200 (Table 6-4) 75.00 0.91 17.93 14.08 42.23 I= 1.00 (Table 6-1) (Import. Factor) 80.00 0.93 18.26 14.34 43.02 h/D = 26.667 85.00 0.94 18.58 14.59 43.77 freq., f = 0.907 Hz. (f < 1) Flexible 90.00 0.96 18.89 14.83 44.49 G= 1.122 (Gust Factor, Sect. 6.5.8) 95.00 0.97 19.18 15.06 45.18 Cf = 0.700 (Table 6-10) (Press. Coef.) 100.00 0.99 19.47 15.28 45.85 (for Mod. Smooth Surface) 105.00 1.00 19.74 15.50 46.49 110.00 1.02 20.00 15.71 47.12 Velocity Pressure (Sect. 6.5.10, Eq. 6-13): 120.00 1.04 20.51 16.10 48.30 qz = 0.00256*Kz*Kzt*Kd*V^2*I 130.00 1.07 20.98 16.47 49.42 Net Design Wind Pressures (Sect. 6.5.13): p = qz*G*Cf (psf) Net Design Wind Forces (Sect. 6.5.13, Eq. 6-20): F = qz*G*Cf*D (lb/ft) Resulting Total Base Shear & Moment: SV(total) = SM(total) =
3.53 324.23
kips ft-kips
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"ASCE798W.xls" Program Version 2.9
Determination of Gust Effect Factor, G: Flexible?
Yes
f < 1 Hz.
1: Simplified Method for Rigid Structure G= N.A. Parameters Used in Both Item #2 and Item #3 Calculations (from Table 6-4): a^ = 0.143 b^ = 0.84 a(bar) = 0.250 b(bar) = 0.45 c= 0.30 l= 320 ft. e(bar) = 0.333 z(min) = 30 ft. Calculated Parameters Used in Both Rigid and/or Flexible Structure Calculations: z(bar) = 48.00 = 0.6*h , but not < z(min) , ft. Iz(bar) = 0.282 = c*(33/z(bar))^(1/6) , Eq. 6-3 = l*(z(bar)/33)^( e(bar)) , Eq. 6-5 Lz(bar) = 362.57 gq = 3.4 (3.4, per Sect. 6.5.8.1) gv = 3.4 (3.4, per Sect. 6.5.8.1) gr = 4.166 = (2*(LN(3600*f)))^(1/2)+0.577/(2*LN(3600*f))^(1/2) , Eq. 6-7 Q= 0.895 = (1/(1+0.63*((B+h)/Lz(bar))^0.63))^(1/2) , Eq. 6-4 2: Calculation of G for Rigid Structure G= N.A. = 0.925*((1+1.7*gq*Iz(bar)*Q)/(1+1.7*gv*Iz(bar))) , Eq. 6-2 3: Calculation of Gf for Flexible Structure b= 0.010 Damping Ratio Ct = 0.041 Period Coefficient T= 1.102 = Ct*h^(3/4) , sec. (Period) f= 0.907 = 1/T , Hz. (Natural Frequency) V(fps) = 132.00 = V(mph)*(88/60) , ft./sec. = b(bar)*(z(bar)/33)^( a(bar))*V*(88/60) , ft./sec. , Eq. 6-12 V(bar,zbar) = 65.23 N1 = 5.043 = f*Lz(bar)/(V(bar,zbar)) , Eq. 6-10 Rn = 0.050 = 7.47*N1/(1+10.3*N1)^(5/3) , Eq. 6-9 hh = 5.119 = 4.6*f*h/(V(bar,zbar)) = (1/ hh)-1/(2*hh^2)*(1-e^(-2*hh)) for hh > 0, or = 1 for hh = 0 , Eq. 6-11a,b Rh = 0.176 hB = 0.192 = 4.6*f*b/(V(bar,zbar)) = (1/ hB)-1/(2*hB^2)*(1-e^(-2*hB)) for hB > 0, or = 1 for hB = 0 , Eq. 6-11a,b RB = 0.883 hd = 0.643 = 15.4*f*L/(V(bar,zbar)) = (1/ hL)-1/(2*hL^2)*(1-e^(-2*hL)) for hL > 0, or = 1 for hL = 0 , Eq. 6-11a,b RL = 0.680 = ((1/ b)*Rn*Rh*RB*(0.53+0.47*RL))^(1/2) , Eq. 6-8 R= 0.817 Gf = 1.122 = 0.925*(1+1.7*Iz(bar)*(gq^2*Q^2+gr^2*R^2)^(1/2))/(1+1.7*gv*Iz(bar)) , Eq. 6-6 Use: G = 1.122
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FIGURE 6-1: Basic Wind Speed
FIGURE 6-1a: Western Gulf of Mexico Hurricane Coastline
FIGURE 6-1b: Eastern Gulf & Southeastern U.S. Hurricane Coastline
FIGURE 6-1c: Mid and Northern Atlantic Hurricane Coastline
