University Academic Center
Eastern USA
Alexander Altemose
I
Structural Option
University Academic Center
•
Introduction
•
General Information
•
Building Layout
•
Current Structure
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
•
Conclusion
General Information
Height: 72 ft (5 floors)
Size: 192,000 sf
Function: Mixed use (A-3, B, S-1)
Construction: September 2005 – August 2007
Cost: $55.7 million
LEED Rating: Gold
Project Team
Owner: (wishes to remain anonymous)
Architect / Engineer: Cannon Design
Construction Manager: Skanska USA Building Inc.
University Academic Center
•
Introduction
•
General Information
•
Building Layout
•
Current Structure
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
•
Conclusion
Ground Floor
Second Floor
Third Floor
Forth Floor
Fifth Floor
University Academic Center
•
Current Structure
Introduction
•
Brick, stone, and metal panel façade
•
General Information
•
Spread footing foundation
•
Building Layout
•
•
Composite metal deck floor system
Current Structure
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
•
Conclusion
•
2” 20 gauge deck with 3.25” LWC topping (typical)
•
Wide flange framing members
•
Concentrically braced frames for lateral support
•
HSS members for diagonal bracing
University Academic Center
•
Introduction
Proposed Goals
•
Proposed Goals
•
Redesign office wing as separate concrete structure
•
Structural Depth
•
Minimize changes to current building form
•
Construction Breadth
•
Strengthen foundations as needed
•
Conclusion
•
Construction breadth
•
•
Cost and schedule reports of structures
Lighting breadth (not included in this presentation)
•
Redesign lighting of computer lab space
University Academic Center
•
Introduction
•
Proposed Goals
•
Structural Depth
•
Redesign Overview
•
Loads and Forces
•
Drift Analysis
•
Member Sizes and Reinforcement
•
Construction Breadth
•
Conclusion
Redesign Overview
Material Properties
•
5” one-way slab
•
Normal weight concrete
•
One-way pan joists
•
f’c = 5,000psi
•
Ordinary moment frames
•
fy = 60,000psi
University Academic Center
•
•
•
Introduction
Proposed Goals
Structural Depth
•
Redesign Overview
•
Loads and Forces
•
Drift Analysis
•
Member Sizes and Reinforcement
Live Loads
Description
Designed Load (psf)
ASCE 7-10 Load (psf)
Slab on grade
Offices
Corridors (elevated
floors)
Stairs
Roof
100
50 + 20 (partitions)
80
100
50 + 15 (partitions)
80
Wind Forces (E-W)
31.79 k
25.63 k
49.77 k
61.74 k
48.10 k
59.67 k
45.97 k
57.02 k
56.76 k
45.76 k
100
30
Wind Forces (N-S)
100
20
215.24 k
266.98 k
11,114.04 k-ft
8,959.68 k-ft
•
Construction Breadth
Design Loads
•
Conclusion
•
Superimposed load for MEP designed for 20 psf
•
All floors designed for 80 psf live load
•
Roof designed for 30 psf live load
•
Wind and seismic loads recalculated for new structure
Seismic Forces (N-S) & (E-W)
99.75 k
90.20 k
66.10 k
44.52 k
22.45 k
323.02 k
17,016.8 k-ft
University Academic Center
•
Introduction
•
Proposed Goals
•
Structural Depth
•
Redesign Overview
•
Loads and Forces
•
Drift Analysis
•
Member Sizes and Reinforcement
•
Construction Breadth
•
Conclusion
Drift Analysis using ETABS
•
Office Wing Story Drifts (Wind)
Floor
Input parameters
• Diaphragms modeled as rigid
•
Icr = 0.35 Ig for beams
•
Mass lumped to diaphragms
•
Icr = 0.7 Ig for columns
•
Supports assumed fixed
Roof
5
4
3
2
Total
Story Height
(ft)
14
14
14
14
16
72
Drift X
(in.)
0.002
0.003
0.055
0.070
0.052
0.24
Drift Y
(in.)
0.098
0.171
0.250
0.301
0.237
1.06
Allowable Drift
(in.)
0.42
0.42
0.42
0.42
0.48
2.16
Pass?
YES
YES
YES
YES
YES
YES
Office Wing Story Drifts (Seismic)
Floor
N
Roof
5
4
3
2
Total
Story
Height
(ft)
14
14
14
14
16
72
Amplified
Drift X
(in.)
0.051
0.084
0.110
0.126
0.088
0.475
Amplified
Drift Y
(in.)
0.598
0.900
1.144
1.211
0.860
4.725
Allowable Drift
(in.)
Pass?
2.52
2.52
2.52
2.52
2.88
12.96
YES
YES
YES
YES
YES
YES
University Academic Center
Slab Design
Joist Design
•
Minimum thickness for deflections: 2.4”
•
Minimum depth for deflections: 19.75”
•
Minimum cover: 1.5”
•
Introduction
•
Minimum thickness for 2hr fire rating: 5”
•
Proposed Goals
•
Minimum cover: ¾”
•
Structural Depth
 Use pan joists: 20” pan depth, 10” rib width, 66” pan width
 Use 5” slab with: #4s @ 8” o.c. for flexure
#4s @ 18” o.c. for shrinkage & temperature
with:
3-#8s top (interior span)
2-#7s bottom (interior span)
•
Redesign Overview
•
Loads and Forces
2-#8s top (exterior spans)
•
Drift Analysis
2-#6s bottom (exterior spans)
•
Member Sizes and Reinforcement
•
Construction Breadth
•
Conclusion
Exterior span
Interior span
University Academic Center
•
Introduction
•
Proposed Goals
•
Seismic Design Category B
 Ordinary concrete moment frames
Lateral Beam Design
•
 Two continuous bars both top and bottom reinforcement
All beams are 25”x24” to match joist depth and column width for
constructability
•
Reinforcement done for 2nd floor and repeated on other floors
Structural Depth
•
Reinforcement economized for weight
•
Redesign Overview
•
Seismic forces controlled for all members except beams 13 and 28
•
Loads and Forces
•
•
As,req ranged from 1.91in2 (the minimum required steel) to 6.65in2
Drift Analysis
•
Member Sizes and Reinforcement
•
Construction Breadth
•
Conclusion
Top:
6-#8s & 2-#9s (2 bars continuous)
Bottom:
5-#7s (2 bars continuous)
University Academic Center
Column Design
Foundation Impact
•
All columns designed the same
•
RAM foundation was used to design new foundations
•
Introduction
•
24”x24” to minimize impact of interior spaces
•
Soil bearing capacity of 3,000 psf
•
Proposed Goals
•
12-#8s reinforcement
•
Sizes increased as expected
•
Structural Depth
•
New footings still reasonably sized
•
Combined footings needed under stairwell
•
Redesign Overview
•
Loads and Forces
•
Drift Analysis
•
Member Sizes and Reinforcement
•
Construction Breadth
•
Conclusion
Ground Floor Column Design Forces
Reference #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Column Pu (kips) Mu (k-ft)
A1
365
182
A2
582
203
A4
605
198
A5
380
179
B2
817
196
B4
855
157
C1.2
588
142
C5
650
142
D2
763
195
D4
816
192
E1.2
477
139
E2
526
181
E3
364
204
E4
543
173
E5
662
139
F2
554
179
F3
361
201
F4
577
171
G1.2
428
136
H2
997
188
H4
1120
186
H5
761
144
J1.2
359
141
J6
61
134
L1.2
269
175
L4
762
205
L5
409
172
K2
443
265
M2
236
441
New Office Wing Design Costs
University Academic Center
•
Introduction
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
•
•
Steel vs. Concrete Structure Cost Reports
•
Steel vs. Concrete Structure Schedules
Conclusion
Material
Labor
Equipment
Total
Total with O&P
Steel vs. Concrete Cost Summary
Formwork
$172,235.55
$407,588.51
$0.00
$579,824.06
$815,942.64
•
Rebar
$153,558.67
$108,194.27
$0.00
$261,752.94
$342,390.60
Concrete
$252,822.92
$53,140.34
$15,985.59
$321,948.85
$376,821.90
Finishing
$0.00
$11,722.32
$0.00
$11,722.32
$17,583.48
$578,617.14
$580,645.43
$15,985.59
$1,175,248.16
$1,552,738.62
Cost summary only includes areas of design that were
changed as part of the concrete redesign
•
Cost based off unit costs in RSMeans 2012
•
Steel is $361,969.52 more expensive than concrete
Total
Original Office Wing Design Costs
Material
Labor
Equipment
Total
Total with O&P
$1,670.70
$8,703.78
$0.00
$10,374.48
$15,224.89
$24,621.93
$19,828.88
$0.00
$44,450.81
$58,945.93
Concrete
$146,751.02
$18,422.33
$5,011.77
$170,185.12
$194,658.14
Finishing
$0.00
$11,722.32
$0.00
$11,722.32
$17,583.48
$4,189.50
$6,247.50
$3,013.50
$13,450.50
$19,110.00
$1,010,429.31
$173,036.06
$49,631.94
$1,233,097.31
$1,467,798.24
$1,511.39
$21,970.86
$1,608.43
$114,473.37
$141,387.47
$1,189,173.85
$259,931.72
$59,265.64
$1,597,753.90
$1,914,708.14
Formwork
Reinforcing
Shear Studs
Steel Framing
Metal Deck
Total
University Academic Center
•
Introduction
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
•
•
Steel vs. Concrete Structure Cost Reports
•
Steel vs. Concrete Structure Schedules
Steel vs. Concrete Schedule Summary
• Durations also calculated using RSMeans 2012
• Concrete design is scheduled to take 230 days longer than original steel
Conclusion
Steel Schedule: 2/6/06 – 5/24/06
Concrete Schedule: 2/6/06 – 1/9/07
Total duration: 107 days
Total duration: 337 days
University Academic Center
•
Introduction
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
•
Conclusion
•
Review and Recommendations
•
Questions?
Review
•
Concrete redesign of office wing
•
One-way pan joist floor system
•
Ordinary concrete moment frame lateral system
Recommendations
•
Seismic forces controlled lateral design
• Further analysis to minimize member sizes on upper floors
•
No disrupting of spaces due to new column layout
• Redesign the original structure without the office wing
•
Floor-to-floor heights remain unchanged
Conclusions
• Concrete moment frames offer a “free” lateral system with
minimal additions as opposed to a steel braced frame system
University Academic Center
Questions & Comments?
Acknowledgements
•
Introduction
•
Proposed Goals
•
Structural Depth
•
Construction Breadth
• The Owner (who wished to remain anonymous)
•
Conclusion
• Skanska USA Building Inc.
•
Review and Recommendations
•
Questions?
Thank you to the following groups and individuals for their
continued support in completing this thesis report:
• The entire AE faculty
• The entire AE student body (especially fellow 5th years)
• My friends and family
University Academic Center
•
Additional slides
University Academic Center
•
Additional slides
Concrete Floor Systems
Guide to Estimating and
Economizing
David A. Fanella
Design Moments for Lateral System Beams
Beam #
University Academic Center
•
Additional slides
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
MD
+
(k-ft)
73.8
79.4
32.8
58.3
12.3
31.1
16.8
48.4
66.6
39.0
7.0
47.0
118.5
67.0
45.6
45.6
3.1
3.1
45.6
67.0
18.4
18.4
49.6
68.3
40.0
6.9
48.2
121.5
37.3
37.3
79.0
84.9
84.9
79.0
MD
-
(k-ft)
147.6
158.8
65.6
116.6
24.5
62.1
33.7
96.7
133.3
78.1
14.0
93.9
236.9
133.9
91.3
91.3
6.2
6.2
91.3
133.9
36.8
36.8
99.2
136.7
80.1
13.8
96.3
243.0
74.6
74.6
158.0
169.9
169.9
158.0
ML
+
(k-ft)
30.4
32.7
13.5
24.0
5.0
9.2
5.0
30.7
42.4
24.8
5.1
29.9
75.3
19.8
31.7
31.7
2.2
2.2
31.7
19.8
9.2
9.2
31.7
43.7
25.6
3.8
30.8
77.8
7.7
7.7
34.0
36.6
36.6
34.0
ML
-
(k-ft)
60.8
65.3
27.0
48.0
10.1
18.4
10.0
61.5
84.7
49.7
10.3
59.7
150.7
39.7
63.5
63.5
4.3
4.3
63.5
39.7
18.4
18.4
63.5
87.5
51.3
7.6
61.7
155.5
15.5
15.5
68.0
73.2
73.2
68.0
Controlling design moment
ME
(k-ft)
65.8
58.9
79.9
63.9
109.1
140.7
127.9
88.7
72.4
86.8
107.2
83.1
71.2
97.1
104.0
99.6
191.2
185.7
89.3
76.3
122.8
119.7
89.7
73.2
87.5
105.8
84.1
67.3
132.1
102.4
68.3
61.4
61.4
68.0
+
MU (1.2D+1.6L+0.5Lr)
(k-ft)
137.2
147.5
61.0
108.4
22.8
52.0
28.2
107.2
147.8
86.6
16.6
104.1
262.7
112.1
105.5
105.5
7.2
7.2
105.5
112.1
36.8
36.8
110.3
152.0
89.1
14.3
107.1
270.2
57.1
57.1
149.2
160.5
160.5
149.2
MU
(1.2D+1.6L+0.5Lr)
(k-ft)
274.3
295.0
121.9
216.8
45.5
104.0
56.4
214.4
295.5
173.1
33.3
208.3
525.4
224.2
211.1
211.1
14.4
14.4
211.1
224.2
73.6
73.6
220.6
304.0
178.1
28.6
214.2
540.4
114.3
114.3
298.4
320.9
320.9
298.4
MU
(1.2D+E+L+0.2S)
(k-ft)
303.7
314.7
185.6
251.9
148.6
233.7
178.3
266.3
317.1
230.1
134.3
255.5
506.2
297.4
277.0
272.6
202.9
197.5
262.3
276.7
185.3
182.3
272.2
324.7
234.8
129.8
261.3
514.4
237.1
207.4
325.9
338.4
338.4
325.6
Beam #
A s,req
2
(in )
1
1.46
2
1.58
3
0.64
4
1.15
5
0.24
6
0.55
7
0.30
8
1.14
9
1.58
10
0.92
11
0.17
12
13
1.11
2.86
14
1.19
15
1.12
16
1.12
17
0.08
18
0.08
19
1.12
20
1.19
21
0.39
22
0.39
23
1.17
24
1.63
25
0.94
26
0.15
27
28
1.14
2.94
29
0.60
30
0.60
31
1.59
32
1.72
33
1.72
34
1.59
+
Bars
Reinforcing for Lateral System Beams
+
+
A s,provided
øMn
A s,req
2
2
Bars
A s, provided
2
-
-
øMn
(in )
(k-ft)
(in )
(in )
(k-ft)
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
3.58
6#7s
3.60
347.3
3.72
5#8s
3.95
380.4
2.15
5#6s
2.20
216.3
2.95
5#7s
3.00
291.8
5#7s
3.00
292.2
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
5#7s
3.00
291.8
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
A s,min
*
(in2)
1.91
Bars
5#6s
1.71
*
*
*
2.72
9#5s
2.79
272.2
2.06
5#6s
2.20
216.6
3.12
4#8s
3.16
306.7
3.75
5#8s
3.95
380.2
2.68
9#5s
2.79
272.4
1.54
*
*
*
2.99
6.45
5#7s
6#8s & 2#9s
3.00
6.74
291.7
626.6
3.51
8#6s
3.52
339.9
3.25
8#6s
3.52
341.0
3.20
8#6s
3.52
341.3
2.35
8#5s
2.48
243.2
2.29
8#5s
2.48
243.4
3.07
7#6s
3.08
299.1
3.25
8#6s
3.52
341.1
2.14
5#6s
2.20
216.3
2.11
5#6s
2.20
216.4
3.20
8#6s
3.52
341.3
3.85
5#8s
3.95
379.7
2.74
9#5s
2.79
272.2
1.49
*
*
*
3.06
6.65
7#6s
6#8s & 2#9s
3.08
6.74
299.2
625.0
2.77
9#5s
2.79
272.1
2.41
8#5s
2.48
243.0
3.86
5#8s
3.95
379.7
4.02
7#7s
4.20
402.9
4.02
7#7s
4.20
402.9
3.86
5#8s
3.95
379.7
A s, provided
øMn
(in2)
2.2
(k-ft)
211.02
University Academic Center
•
Additional slides
University Academic Center
•
Original recessed lighting
Additional slides
Reflected Ceiling Plan
Computer Lab Room 2139
New pendant lighting