1. LDG requires Excel
and macros enabled

2. Ly Lx Ly Lx Lx Ly Lx Ly Lx Ly
LDG computes floor area A = (Lx Ly) assuming rectangular plans.
to get correct seismic values, prorate dead load to represent the actual floor area.
For example, if the floor area of a plan is 30% smaller, reduce the dead load 30%

3. Enter design factors prior to running LDG
Seismic data brown
Wind data green
Copy columns TU into AB as default if needed
Data position is critical for LDG to run properly

4. Press Ctrl-Shift-R to start LDG (Excel macro) 20
Press Ctrl-Shift-R to start LDG (Excel macro)
Select input type: 0, 1, 2, or 3
0 = as is, run current structure displayed
or as modified
1 = uniform: floors, story height, and mass
2 = tapered: changing from base to top
3 = custom: unique floors or stacks of floors

5. Lateral loads - acting primarily horizontally are: Wind load
IBC Table Importance factors
Category
Seismic
Use Group
Nature of Occupancy
Importance
Factors
Snow
Wind I
Low hazard structures:
Agriculture, temporary, minor storage 1
0.8
0.87 II
Structures not in categories I, III, IV
III
Facilities such as:
Occupancy > 300 people per area
Elementary schools > 250 students
Colleges > 500 students
Occupancy > 5000
1.25
1.1
1.15 IV
Essential facilities, such as:
Hospitals, polices and fire stations
1.5
1.2
Lateral loads - acting primarily horizontally are:
Wind load
Seismic load
Earth pressure on retaining walls (not in LDG)

6. Fa factors, IBC Table 1615.1.2 [1] (low-rise)
Sds = (2/3)(Fa SS) [Ss = top line]
Fv factors, IBC Table [2] (high-rise)
Sd1 = (2/3)(Fv S1) [S1 = top line]
Importance factors
Press Ctrl-Shift-R to run LDG
US wind velocity map

7. Seismic Design
V = Cs W = seismic base shear (lateral building base)
W = mass = (DL + 25% storage LL)
CS = I Sds / R [seismic equation for T<TS]
CS = I Sd1/(RT) [for T>TS<TL]
CS = I Sd1 TL / (RT2) [for T>TL]
I= Importance Factor [see slide 1]
Sds = (2/3)(Fa SS) [see Fa table - low-rise]
Sd1 = (2/3)(Fv S1) [see Fv table - high-rise)
TS = Sd1/Sds [see left]
T ~ 0.1(# stories) [building period = cycles/second]
SS & S1 [see USGS Table]
R = R-factor [see IBC Table ]
TL = Time Laps [range 4 -12, ASCE7 Fig 22-15]
Note: CS ~ 0.03 for high-rise moment frames
CS ~ 0.15 for wood structures
CS ~ 0.30 for masonry structures
W = w A [A = floor area]
w ~ 25 psf for wood structures
w ~ 70 psf for steel structures
w ~ 150 psf for concrete structures

8. USGS seismic factors
USC: SS = 1.85 (low-rise), S1 = 0.64 (high-rise)

10. Wind Design
V = p A = wind base shear (lateral building base)
p = wind pressure (in psf = pounds / square foot)
A = exposed tributary area
p = wind pressure (psf)
p = V2 I Cp G Kd Kz Kzt
V = velocity (mph)
I = Importance Factor (see slide 1)
Cp = external pressure coefficient
Cp = 0.8 windward
Cp = 0.2 to 0.5 leeward
G = Gust factor
G = 0.85 for rigid structures
G = for fabric structures
Kd = 0.85 for buildings [directionality factor]
Kz = 2.01 (Z/Zg)2/
Z = height above ground
Exposure Zg 
B Inner city
C Open area
D Near ocean or lake
Kzt = Velocity Factor = 1 for flat sites

11. Wind pressure (IBC/ASCE 7 Method 2, Analytical Procedure)
p = qGCp–qi(GCpi) [minimum p = 10 psf (480 Pa)]
q velocity pressure (defined below)
qz for windward wall (evaluated at height z above ground)
qh for leeward wall (constant, per mean roof height h)
G gust factor (Rigid G=0.85, fabric structure G=> 1.2)
GCpi Internal pressure (± 0.18 for enclosed structures)
Cp pressure coefficient (from ASCE 7 figures and tables)
Cp = (windward walls)
Cp = to (leeward walls)
Cp = to (for roofs)
q= I KzKztKdV2 (q = velocity pressure in psf)
V = wind speed, mph (IBC Fig. 1609, or local speed)
I = Importance factor (IBC table )
I = 1 (all structures not listed below)
I = (hospitals, police and fire stations, etc)
I = (agricultural and temporary facilities)
KZt Topography factor (KZt = 1 for regular sites)
Kd Directionality factor (Kd = 0.85 for most structures)
KZ Exposure factor (graph at left, min. 0.7 for gladding)
B = Exposure B (inner city, protected)
C = Exposure C (open area, unprotected)
D = Exposure D (near ocean or large lakes)
Graph see Structure and Design page 577

12. Optional select and copy (Ctrl C)
data to make graphs at another sheet
or make graphs on this Excel sheet

13. Paste selected data into another Excel sheet
Select a chart type
Paste selected data into another Excel sheet
Select data

14. Fs &Vs (k)
Fwx &Vwx (k)
Fwy &Vwy (k)

15. Select R
Select Ss &S1
Select TL
Select wind speed, etc.

16. 14-story seismic force Fs & shear Vs

17. 14-story wind overturn moment
Simpson
Tokyo EQ