LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle LDG is an Excel program to design and visualize design for lateral wind and seismic forces LDG requires some knowledge of lateral force design LDG requires a PC with MS Excel macros Enabled Press > for next step, < for previous step Press Esc to end

LDG: Lateral Design Graph - Tutorial Copyright Prof Schierle LDG: Lateral Design Graph - tutorial Lx Ly 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%

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle 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

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle 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 20

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Lateral loads - acting primarily horizontally are: Wind load Seismic load Earth pressure on retaining walls (not in LDG) IBC Table Importance factors CategorySeismic Use Group Nature of OccupancySeismic Importance Factors Snow Importance Factors Wind Importance Factors IILow hazard structures: Agriculture, temporary, minor storage IIIStructures not in categories I, III, IV111 IIIIIFacilities such as: Occupancy > 300 people per area Elementary schools > 250 students Colleges > 500 students Occupancy > IVIIIEssential facilities, such as: Hospitals, polices and fire stations

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle F a factors, IBC Table [1] (low-rise) S ds = (2/3)(F a S S )[S s = top line] F v factors, IBC Table [2] (high-rise) S d1 = (2/3)(F v S 1 ) [S 1 = top line] Importance factors Press Ctrl-Shift-R to run LDG US wind velocity map

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Seismic Design V = Cs W = seismic base shear (lateral building base) W = mass =  (DL + 25% storage LL) C S = I S ds / R [seismic equation for T<T S ] C S = I S d1 /(RT) [for T>T S <T L ] C S = I S d1 T L / (RT 2 ) [for T>T L ] I= Importance Factor [see slide 1] S ds = (2/3)(F a S S ) [see F a table - low-rise] S d1 = (2/3)(F v S 1 ) [see F v table - high-rise) T S = S d1 /S ds [see left] T ~ 0.1(# stories) [building period = cycles/second] S S & S 1 [see USGS Table] R = R-factor [see IBC Table ] T L = Time Laps [range 4 -12, ASCE7 Fig 22-15] Note: C S ~ 0.03 for high-rise moment frames C S ~ 0.15 for wood structures C S ~ 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

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle USC: S S = 1.85 (low-rise), S 1 = 0.64 (high-rise) USGS seismic factors

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle 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 = V 2 I C p G K d K z K zt V = velocity (mph) I = Importance Factor (see slide 1) C p = external pressure coefficient C p = 0.8 windward C p = 0.2 to 0.5 leeward G = Gust factor G = 0.85 for rigid structures G = for fabric structures K d = 0.85 for buildings [directionality factor] K z = 2.01 (Z/Zg) 2/  Z = height above ground Exposure Zg  B Inner city C Open area D Near ocean or lake K zt = Velocity Factor = 1 for flat sites

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Wind pressure (IBC/ASCE 7 Method 2, Analytical Procedure) p = qGC p –q i (GC pi ) [minimum p = 10 psf (480 Pa)] q velocity pressure (defined below) q z for windward wall (evaluated at height z above ground) q h for leeward wall (constant, per mean roof height h) G gust factor(Rigid G=0.85, fabric structure G=> 1.2) GC pi Internal pressure (± 0.18 for enclosed structures) C p pressure coefficient(from ASCE 7 figures and tables) C p = 0.8 (windward walls) C p = to (leeward walls) C p = to (for roofs) q= I K z K zt K d V 2 (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 = 1.15 (hospitals, police and fire stations, etc) I = 0.87 (agricultural and temporary facilities) K Zt Topography factor (K Zt = 1 for regular sites) K d Directionality factor(K d = 0.85 for most structures) K Z 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

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Optional select and copy (Ctrl C) data to make graphs at another sheet or make graphs on this Excel sheet

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Paste selected data into another Excel sheet Select a chart type Select data

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Fwx &Vwx (k)Fwy &Vwy (k) Fs &Vs (k)

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle Select R Select Ss &S1 Select TL Select wind speed, etc.

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle story seismic force Fs & shear Vs

LDG: Lateral Design Graph - tutorial LDG: Lateral Design Graph Copyright Prof Schierle story wind overturn moment Read chapter 9