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Load calculation
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Dead load & Live load:
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Snow load: ASCE 7-05, IBC-2006
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Ice load: ASCE 7-02 &
05
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Wind load: ASCE 7-02
& 05, IBC-2006
Seismic load: ASCE 7-98, IBC -2000 -
Lateral force distribution: Vertical
distribution, Horizontal distribution (flexural diaphragm, rigid
diaphragm).
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Load combinations: ASCE 7-02.
Load Combinations:
ASCE 7-05 & 02
List below are load combination in ASCE 7-02 & 05 that involve Dead
load, live load, roof live load, snow load, wind load and earthquake
load. See ASCE 7 For load combinations other loading such as fluids
pressure, floor load, rain load, temperature change, ice load etc.
Basic Combination:
1.4
D
1.2
D +1.6 L + 0.5(Lr
or S)
1.2
D + 1.6 (Lr
or S) + (L* or 0.8W)
1.2
D + 1.6 W + L* + 0.5 (Lr
or S)
1.2
D +
1.0 E + L* + 0.2S
0.9
D +
1.6 W
0.9
D + 1.0 E
Note:
*Live
load can be reduced by 50% if it is less than or equal to 100 psf except
garages or public assembly.
ASCE
7-05:
E
= Eh + Ev for load combination, 1.2
D +
1.0 E + L* + 0.2S
E
= Eh - Ev for load combination, 0.9
D + 1.0 E
where
Eh , Ev are horizontal and vertical seismic effect.
Allowable
stress design load combinations:
D
+ F
D
+ L
D
+ F + (Lr or S)
D
+ 0.75 L + 0.75 (Lr or S)
D
+ (W or 0.7 E)
D
+ 0.75 (W or 0.7 E) + 0.75 L + 0.75 (Lr or S)
0.6
D + W
0.6
D + 0.7 E**
Note:
**
seismic force calculated from ASCE 7 is for strength design. The factor,
0.7, is to reduce it to allowable stress level.
Where
D:
dead load,
L:
live load,
Lr:
roof live load,
E:
seismic force,
W:
wind load
S:
snow load.
Occupancy
Category
ASCE 7-05
(Table 1-1)
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Low
Hazard facility:
Agricultural
facility, temporary facility, minor storage facility
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I |
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All
buildings and other structure not in I, III, and IV
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II |
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Buildings
and other structures are substantial hazard to human life
Example:
Building
with more than 300 people in one area
Day care
with more than 150 capacity
Elementary
and secondary school has more than 250 capacity
College
has more than 500 capacity
Hearth
care has more than 50 capacity
Jail and
detention facility
Power
station, water and sewage treatment facility.
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III |
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Building
and other structures designed as essential facilities:
Example:
Hospitals
and emergency health care facility
Fire,
rescue, ambulance, and police stations
Communication
towers, fuel storage tanks,
Aviation
and traffic control center
Water
storage and pump station
National
defense facility |
IV |
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