Final Capstone Design Presentation MAE 4194 – Mechanical Design 2
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Transcript of Capstone Design Presentation
Structural Design of Office Building with Design
Variations for Natural Hazardous Environments
Nkonyeasua G. Adaikpoh
Tennessee State University,Tennessee State University,
Department of Architectural Engineering
April 15, 2009
Introduction
Mr. Moneybags International
has decided to expand his
company’s offices to 3 new
markets. In a bid to move markets. In a bid to move
quickly he hires a Structural
Engineer to perform a feasibility
design per his requirements and
thereafter report the results
and cost.Structural Analysis and Design - Nkonyeasua G. Adaikpoh
Design Evolution
Architectural Components
Governing Texts: Governing Texts:
1. International Building Code (IBC 2006)
2. Architectural Graphics Standards
3. The Architect’s Studio Companion
Structural Analysis and Design - Nkonyeasua G. Adaikpoh
Locations Characteristics
San Francisco Oklahoma CityNew Orleans
� All in the downtown areas of the cities.
� Stiff soils – well compacted
� Disaster prone – added lateral forces
Caused damage
of $1 Billion+ in
2005
Hurricanes
In San Andreas
fault zone.
Pleasant
weather
Earthquakes
Structural Analysis and Design - Nkonyeasua G. Adaikpoh
Gently rolling
hills & shrubs
Temperate, sub-
humid climate
Tornadoes
Severe cyclones
originating over
equatorial
regions,
accompanied by
torrential rain,
Ground shaking
caused by
tectonic
processes.
Measured on the
Richter
Disaster Definitions
Earthquakes TornadoesHurricanes
Violent storms
characterized by
whirling funnels
of wind moving
at great speeds.
Measured on an torrential rain,
lightning, &
winds with
speeds >74mph
Measured on a
Saffir-Simpson
scale, in
categories.
Richter
magnitude scale,
in magnitudes.
Measured on an
enhanced Fujita
scale, in
categories.
USGS NOAA NOAA
Effects on Buildings
Earthquakes TornadoesHurricanes
Photo courtesy USGS and NGDC Stan Honda/AFP/Getty Images © How Stuff Works
Requirements Translation
Preliminary Design
� Occupancy classification – B - Business
� 3-Hour Noncombustible construction
� Type I-A
� Sprinklered building
� Unlimited height and area
� Site cast concrete system
� Two-way post-tensioned flat plate � Two-way post-tensioned flat plate slab with 30’ x 30’ bays
� 300’ maximum travel distance
� Open plan
Planning
Maximum travel
distance – 300ft
Tower Shape
b
(in)
h
(in)
Area, Ai
(in2)
xi
(in) Aixi (in3) yi (in) Aiyi (in3)
dx (xi-
xbar)
dy (yi-
ybar)
Ix =bh3/12 +
Adx2 (in4) Ix TOWER
Iy =bh3/12 +
Ady2(in4) Iy TOWER
%
stiffness x
%
stiffness y
To
we
r 1
-
To
p le
ft
sta
ir 252130 32760 480 15724800 1381 45241560 -421.05 360.40 5854056115
1592015420
4301279897
1184767152 42.22% 22.82%228106 -24168 480-11600640 1381
-
33376008 -421.05 360.40-4262040695 -3116512746
To
we
r 2
-
To
p r
igh
t
sta
ir 252130 32760
132
0 43243200 1381 45241560 418.94 360.40 5796018744
1576793897
4301279897
1184767152 41.82% 22.82%228106 -24168
132
0-31901760 1381
-
33376008 418.94 360.40-4219224847 -3116512746
To
we
r 3
-B
ott
om
left
ele
vato
r
110232 25520 805 20543600 640 16332800 -96.054 -380.59349925238.7
249374333.6
3811194440
1284499982 6.61% 24.74%86208 -17888 805-14399840 640
-
11448320 -96.054 -380.59
-
100550905.1 -2526694458
Bo
tto
m
Shear Wall Stiffness Distribution – Code compliantT
ow
er
4 -
Bo
tto
m
rig
ht
sta
ir
128256 32768 988 32374784 640 20971520 86.945 -380.59426667210.7
352493316.8
4925603018
1538736157 9.35% 29.63%104232 -24128 988-23838464 640
-
15441920 86.945 -380.59
-
74173893.91 -3386866861
SUM = 33456 30145680 34145184 3770676967 5192770442 100.00% 100.00%
Center of stiffness for the building
xbar = 901.1in = 75.1ft
ybar = 1020.6in = 85.0ft
Ix = 3770676967in4
Iy = 5192770442in4
Shear Wall Stiffness Distribution – Code compliant
Column stiffness check
Largest column size = 36 x 36 in
Shape b (in) h (in)
Area, Ai
(in2) xi (in) Aixi (in3) yi (in)
Aiyi
(in3)
Ix =bh3/12
(in4) 6IX (in4) Iy =bh3/12 (in4) 6Iy (in
4)
Co
lum
n
36 36 1296 18 23328 18 23328 139968 839808 139968 839808
Check: I ≥ 6ICheck: IWALL ≥ 6ICOLUMNS
Smallest IX WALL = 249374333.6 > 839808in4
Smallest IY WALL = 1184767152 > 839808in4
ACI 318 Code discussion on slenderness
and stiffness
Architectural Programming
� Shape from McCormac & Nelson
� Open plan - 30ft x 30ft grid
� Dimensions - 150ft x 120ft� Dimensions - 150ft x 120ft
� Floor Area - 17,100sf
� Building Area - 17,100sf x 20 floors
� Occupant load- 100sf/occupant
� Egress requirement- 0.2”/occupant
� Min. egress width/floor = 0.2” x 171 occupants
= 34.2”
� Exit stairway - 30” clear
Architectural Plans
South elevation
Typical Floor Plan
Architectural Plans
Section and partial 3-D
view
Design Evolution Summary
Mixed use structure with parking for all occupants in same building.
Single use structure, 20 Mid-rise building
in 3 locations
Single use structure, 20
floors, regular floor plan
in 3 locations.
Design Evolution
Structural Components
Governing Texts:
1. International Building Code (IBC 2006)
2. ASCE/SEI 7-05 Minimum Design Loads for 2. ASCE/SEI 7-05 Minimum Design Loads for Buildings and Other Structures
3. ACI 318-05 Building Code Requirements for Structural Concrete
4. Building Codes Illustrated
5. Building Structures Illustrated
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT
Structural Effects/Requirements
Produce lateral forces
which the building
must resist via a LFRS
– Lateral Force
Resisting system.
Aims:
� Durability
� Ductility
� Reliability
Structural Requirements
LFRS – Shear Walls
Diaphragm – 2-way flat slabs
Aims:
� Durability
� Ductility
� Reliability
Loading
Dead Load:Dead Load:
8” slab - 100psf
Partition - 10psf
MEP - 8psf
Ceiling - 2psf
Misc. - 5psf
Total - 125psf
Loading
Live Load:
80 psf – considering
light storage, and
partition locations
Loading: Wind Loads
� MWFRS is
designed to resist
high hurricane and
tornado force
winds.
V = 150mph, New Orleans
ex = 2.75 In
ey = 300.625 In
Case 1
Heights (ft) PWx PLx
PE-W
(psf) ForceE-W (kips) PWy PLy
PN-S
(psf)
ForceN-S (kips)
15 7.0 -37.3 44.4 39.9 7.0 -37.3 44.4 49.9
30 11.4 -37.3 48.7 43.8 11.4 -37.3 48.7 54.8
45 14.2 -37.3 51.5 46.4 14.2 -37.3 51.5 58.0
60 16.3 -37.3 53.7 48.3 16.3 -37.3 53.7 60.460 16.3 -37.3 53.7 48.3 16.3 -37.3 53.7 60.4
75 19.0 -37.3 56.4 50.7 19.0 -37.3 56.4 63.4
90 20.0 -37.3 57.4 51.6 20.0 -37.3 57.4 64.5
105 21.0 -37.3 58.4 52.5 21.0 -37.3 58.4 65.6
120 21.0 -37.3 58.4 52.5 21.0 -37.3 58.4 65.6
135 23.5 -37.3 60.9 54.8 23.5 -37.3 60.9 68.5
150 25.0 -37.3 62.3 56.1 25.0 -37.3 62.3 70.1
165 26.0 -37.3 63.3 57.0 26.0 -37.3 63.3 71.3
180 27.0 -37.3 64.3 57.9 27.0 -37.3 64.3 72.4
195 27.8 -37.3 65.1 58.6 27.8 -37.3 65.1 73.2
210 28.5 -37.3 65.9 59.3 28.5 -37.3 65.9 74.1
225 29.3 -37.3 66.7 60.0 29.3 -37.3 66.7 75.0
240 30.1 -37.3 67.5 60.7 30.1 -37.3 67.5 75.9
255 30.9 -37.3 68.2 61.4 30.9 -37.3 68.2 76.8
270 31.6 -37.3 68.9 62.0 31.6 -37.3 68.9 77.6
285 32.3 -37.3 69.6 62.7 32.3 -37.3 69.6 78.3
300 33.0 -37.3 70.3 63.3 33.0 -37.3 70.3 79.1
305 33.2 -37.3 70.5 63.5 33.2 -37.3 70.5 79.4
Loading: Wind Loads
� Designed to withstand
Code-required wind loads
� Includes torsional moments
due to eccentricity of the
shear walls and quartering
winds.winds.
Loading: Wind Loads
� Wind loading
animation – 100%
amplification
� Chapter 11, 12, and 14 in
ASCE/SEI 7-05 code
Loading: Seismic Loads
Seismic Loads Development
Loading: Seismic Load Development
1. Determine the mapped
maximum considered
earthquake (MCE) spectral
response SS and S1.
2. Determine if the structure is
exempt from seismic
requirements
6. Determine Seismic Importance Factor, I
7. Determine seismic base shear, V
8. Distribute V over the height of the
building
9. Determine redundancy coefficient, ρ
10. Determine seismic load effects, E and EM
Steps to Seismic Design
requirements
3. Determine seismic design
requirements (SDC)
4. Determine Analysis
procedures
5. Determine R, Response
Modification Coefficient
10. Determine seismic load effects, E and EM
11. Check drift control requirements
Base shear distribution over the height of the building - San Francisco
Level
Story
Height
(ft)
Height
(ft)
Weight
(kips) WiHik Cvx
Force F
(kips)
MTx
(kip-
ft)
MTy
(kip-
ft)
1 15 15 3240 571320 0.003 8 48 60
2 15 30 3240 2147072 0.012 30 180 225
3 15 45 3240 4657801 0.025 65 391 489
4 15 60 3240 8068892 0.044 113 678 847
5 15 75 3240 12356971 0.067 173 1038 1298
6 15 90 3240 17504439 0.095 245 1471 1838
7 15 105 3240 23497225 0.128 329 1974 2468
8 15 120 3240 30323630 0.165 425 2548 3185
9 15 135 3240 37973664 0.207 532 3190 3988
10 15 150 3240 46438621 0.253 650 3902 4877
Total 150 32400 183539635 1.000 2570
Loading: Seismic Loads
� Designed to withstand
Code required seismic loads
� OTM shown
Loading: Seismic Loads
� Seismic loading
animation – 100%
amplification
Loading: Seismic Loads
�Seismic loading
animation – 50%
amplification
Design: pca Column – Shear Wall Design
Design: pca Column – Column Design
� Same building as
for New Orleans
� Wind speed is
less in Oklahoma
than for New
Orleans, but the
New Orleans
� More building –
20 floors
� Ordinary R.C.
Shear Walls
� Column
dimensions– 30”
� Less building –
10 floors
� Special R.C.
Shear Walls
� Column
dimensions – 28”
Construction Comparison
San Francisco Oklahoma City
Orleans, but the
disasters exact
similar forces
� Rough concrete -
11000 yd3
� Reinforcing -
700 tons
dimensions– 30”
x 30”
� Rough concrete -
11000 yd3
� Reinforcing -
700 tons
dimensions – 28”
x 28”
� Rough concrete
– 6730yd3
� Reinforcing –
375 tons
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT
New Orleans
Concluding summary
San Francisco Oklahoma City
� More building – 20
floors
� 54% more rebar
� More than twice
the amount of SF’s
concrete.
� Cost - $ 139.90/sf,
$45,328,000 total
� More building – 20 floors
� About twice as much rebar
� 61% more concrete than SF
� Cost - $139.90/sf, $45, 328,000 total
� Less building – 10
floors
� 46% less
reinforcing bars
� 39% less concrete
� Cost - $161.85/sf,
$27,677,000 total
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT
F.A.Q.• Isn’t the building a tall building? The Council of tall buildings states
that “A tall building is not defined by its height or number of stories. The important criterion is whether or not the design is influenced by some aspect of “tallness.” It is a building in which “tallness” strongly influences planning, design and use. It is a building whose height creates different conditions in the design, construction and operation from those that exist in “common” buildings of a certain region and period.
• Did you consider the soils in designing? Yes, e.g. the seismic design category is based on a mixture of the location on the earth, the soil category is based on a mixture of the location on the earth, the soil type, and the surrounding environment.
• Why didn’t you consider flood loads in your design since the areas you mentioned frequently have flooding? Flood loads are inconsequential to commercial construction once the building is above a certain height, and the wave crest won’t have a significant effect on the building.
• How about the cost of land and building in these places? Well the client would have already sourced the amounts for land in the 3 locations and the building costs differ but I used a national average.
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT
F.A.Q. Contd.
• What are rigid diaphragms? Rigid diaphragms according to the ASCE 7-05 code are diaphragms of concrete slabs or concrete filled metal deck with span-to-depth ratios of 3 or less in structures that have no horizontal irregularities.
• Did you consider P-delta effects in your design considering the height of the building? Yes, in the analysis and design software, RISA-3D and pca-Column I specified the program to calculate P-Δeffects.
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT
Acknowledgements
• Russell Skrabut, PE, LEED AP
• C.W. Yong, PE, LEED AP
• Professor Michael Samuchin, PE, LEED AP
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT
New Orleans
THE END
San Francisco Oklahoma City
QUESTIONS?
� More building – 20
floors
� 54% more rebar
� More than twice
the amount of SF’s
concrete.
� Cost - $ 139.90/sf,
$45,328,000 total
� More building – 20 floors
� About twice as much rebar
� 61% more concrete than SF
� Cost - $139.90/sf, $45, 328,000 total
� Less building – 10
floors
� 46% less
reinforcing bars
� 39% less concrete
� Cost - $161.85/sf,
$27,677,000 total
Structural Analysis and Design - Nkonyeasua G. Adaikpoh, EIT