sap 2000 wind load analysis
TRANSCRIPT
Thanh Huynh
Why Modular Structures?What is a Load Path and Load Sharing?Structural ModelShear Wall CorrelationStructural DetailsWind LoadsSAP 2000 Analysis MethodSAP 2000 Output VerificationSAP2000 ResultsSAP 2000 DiscussionFuture Work
In 2004… “Prefab housing production in North America as a whole is about 300,000 units per year and valued at $11 billion USD. Consumer acceptance of such products is rising steadily and emphasis is turning towards ‘higher end’ designs.”
-Smith et.al., “High Performance Modular Wood Construction Systems”, University of New Brunswick 2007.
2011 Mcgraw Hill report shows that 25% of architects who utilize BIM (Building Information Modeling) software also incorporated modular components in their plans.
Overall lack of attention to modeling modular structures.
A load path is the path that forces are transferred between the elements of an assembly to safely travel into the foundation.
Different for• Gravity Loads• Lateral Loads
Load Sharing is the ability of individual components to work together to distribute loads that are applied.
Dependent on the stiffness of the member relative to the stiffness of surrounding elements.
“stiffness attracts load”– Dr. Thomas Miller
Simplified Model of End Wall for Calibration
• Same shear wall dimensions as analog but with no openings. • Spacing of studs changed to remain consistent with no double
studs and to create symmetry.• Calibration performed for both end wall and side walls• Different layers of sheathing analyzed separately• Pinned at the ends and out-of-plane deformations restrained• Moments released at both ends for all frame elements
South Wall
West Wall
Case A
6 ft
35.1 psf
23.3 psf
37.3 psf
26.0 psf
17.5 psf
22.8 psf
South Wall
Case B
West Wall
37.3 psf
26.0 psf
17.5 psf
22.8 psf
3 ft
35.1 psf23.3 psf
6 ft
Loading Diagram SW Corner
Load case A on the Northwest Corner. Deflected shapes are reasonable.Should expect relatively small deflections in the horizontal direction perpendicular to wind
West Wall
Case A
6 ft
North Wall
35.1 psf
23.3 psf
37.3 psf
26.0 psf
17.5 psf
22.8 psf
0.6D+0.6W NW A
Win
d D
irec
tio
n
Qualitative Check
0.15in deflection in the global y direction
• Ties and CMU elements will engage to resist overturning• Only ties resist horizontal displacements
z
y
Win
d D
irec
tio
n
Qualitative Check
Displacement in the global z direction (in)
• Largest upward deflections at center of roof.• Deflections are upward in the direction of roof uplift.• Smaller upward deflection due to steel column elements at the center.
Wind Direction
-1916.5
0.1 -1916.4 -1951.7 -1950.4
-1888.2
-119.2
-617.8
-578.7
0.1-1192.4
-189.0 -254.8 -26.80.1
-1112.2
1573.2 997.4 467.0 1321.0 227.4 477.0 1388.3 222.4 307.4 1450.7 284.4 815.9 2313.4
261.5 109.9 73.7 273.5 32.7
318.9 220.3 192.8 419.4
-200
-150
-100
-50
0
50
100
150
200
-500 -400 -300 -200 -100 0 100 200 300 400 500
y(i
n)
x (in)Location and Reactions in the z (lbs)
North
South
North
South
• Reactions in ties and CMU from 0.6D+0.6W Northwest Corner Load Case A
Wind Direction
Tension in Ties 0.6D+0.6W NW A Case
CMU
Ties
Dead Load
Wind Uplift
Lateral Wind
1.57k
1.92k
1.92k
0.618k
1.19k
Z
Y
Tie Reactions
CMU Reactions
So
uth
Wa
ll
No
rth
Wa
llWest Wall
Snapshot of reactions along the West Wall
FBD
CMU Response to overturning
Tie response to horizontal displacement
Total vertical load at foundation level is negligible.
Tie Response to overturning
Ties along north wall are not engaged. (more horizontal than vertical displacement)
0.6D+0.6W NW A Case FBD
-1916.5
0.1-617.80.1
-1192.4
1573.2
Nor
Phase 2 OptionsWall test