1. Acterna Headquarters John M Sekel Germantown, Maryland
The Pennsylvania State University
Architectural Engineering
2003 Senior Thesis Presentation
Structural Emphasis

2. Presentation Overview
Existing Building
Proposal
Structural Redesign
Construction Considerations
Architecture Redesign
Mechanical Considerations
Conclusions and recommendations
Structural Option
John M Sekel

3. Existing building Project Team Owner: Milestone Industrial, LLC
Architect: Hickok, Warner, Fox Architects
Structural Engineer: Structural Design Group
MEP Engineer: Girard Engineering
General Contractor: L.F. Jennings
Structural Option
John M Sekel

4. Existing Building General New corporate campus for Acterna Corporation
Site clearly visible off I-270 outside Washington, D.C.
Six story, 187,500 sf office building
253’x126’ building footprint
$10 million construction cost
BOCA 1996 design code
Structural Option
John M Sekel

5. Existing Building Structural Floor framing Foundations
Composite beam and slab construction
50 ksi wide flange shapes
30’x25’ typical bays
3 ¼” lightweight concrete slab on 2” metal decking
2 – transfer girders over conference room on level 1
Foundations
Spread footing foundations
4” first floor slab on grade
Structural Option
John M Sekel

6. Existing Building Structural Lateral Frames
2 – braced frames in each direction
Structural Option
John M Sekel

7. Existing Building
Typical framing plan
Structural Option
John M Sekel

8. Existing Building Mechanical Electrical/Lighting
VAV boxes with electric duct heaters and reheat coils with VFD
2 – cfm VAV A/C units per floor
2 – 350 ton cooling towers
Plate and frame heat exchanger
Electrical/Lighting
277/480 volt, 3-phase, 4 wire system
4000 amp primary switchboard
2000 amp secondary switchboard
2’x4’ 277 volt florescent fixtures
Structural Option
John M Sekel

9. Presentation Overview
Existing Building
Proposal
Structural Re-design
Construction Considerations
Architecture Re-design
Mechanical Considerations
Conclusions
Structural Option
John M Sekel

10. Proposal Structural design goals
Eliminate intermediate column line outside of core
Use long span steel from core to exterior
Economize the structure
Design for ease of construction
Update to IBC 2000 code
Structural Option
John M Sekel

11. Proposal Architectural design goals
Reflect structural changes in the façade
Open interior spaces, column free areas
Add glazing to lessen “hole-punch” look
Emphasize the drum shape
Predominant architectural feature
Structural Option
John M Sekel

12. Proposal Construction goals Mechanical considerations
Reduce construction cost
Reduce construction schedule time
Design building for ease of construction
Mechanical considerations
Analyze impact of façade design on system
Structural Option
John M Sekel

13. Presentation Overview
Existing Building
Proposal
Structural Re-design
Construction Considerations
Architecture Re-design
Mechanical Considerations
Conclusions
Structural Option
John M Sekel

14. Structural depth Framing Re-design Overview
New bay size outside of core 30’x50’
50 ksi wide flange shapes
Most readily available shapes
Possible options
3 ¼” lightweight concrete slab on 2” metal deck
2 hour fire rating
Re-size frames for additional gravity load
IBC 2000 lateral loads
Structural Option
John M Sekel

15. Use 50’ to maintain core size
Structural depth
Economic steel design measures
Redundant shapes
Simple shear tab connections
Efficient spacing and span direction
Efficient bay size
Original
1.5 * 25’ = 37.5’
Redesign
1.5 * 30’ = 45’
Use 50’ to maintain core size
Structural Option
John M Sekel

16. Structural Depth
New framing plan
Structural Option
John M Sekel

17. Structural Depth New gravity member sizes Typical Girders
Original: W18
New Design: W24
Typical Beams
Original: W14
Typical Interior Column
Original: W12x65
New Design: W14x120
Typical Exterior Column
Original: W10x54
New Design: W14x90
Deflection criteria controls (L/360)
Structural Option
John M Sekel

18. Structural Depth ƒn calculation Vibration Analysis ap/g calculation
0.18 √[g/(Δg+Δj)]
3.19 Hz
Vibration Analysis
Typical bay analyzed
Wj=157.8 kips
Δj=1.040”
Wg=156.8 kips
Δg’=0.191”
Po=65 lb
β=0.03
W=157.6 kips
ap/g calculation
[Po e^(-0.35ƒn)]/βW
0.45%g
Structural Option
John M Sekel

19. Structural Depth ap/g vs. fn chart Most accurate between 4 and 8 Hz
Combined mode frequency is 3.19 Hz
Peak acceleration is 0.45% of g
Meets acceptable criteria for office buildings
0.64% of g at 3.19 Hz
Structural Option
John M Sekel

20. Structural Depth New Braced Frame Sizes Foundations
Original frame layouts and geometries were maintained
Frames 1 & 4: Inverted “V”
Frames 2 & 3: Diagonal
All web members are TS 10”x10”x5/16”
Column sizes increased for higher gravity load
Designed for member strength and drift
Foundations
Spread foundation system
Size and depth increased due to greater load
Structural Option
John M Sekel

21. Presentation Overview
Existing Building
Proposal
Structural Redesign
Construction Considerations
Architecture Redesign
Mechanical Considerations
Conclusions
Structural Option
John M Sekel

22. Construction Breadth Cost Comparison
RS Means cost estimate for both systems
Cost includes material, labor and equipment
Item
Original Design
New Design
Difference
Structural Steel
$1,182,852
$1,263,433
$80,581
Fire Proofing
$145,957
$118,316
$28,641
Foundations
$182,790
$159,800
$22,990
Total
$1,511,599
$1,541,549
$28,950
Structural Option
John M Sekel

23. 6 ½ weeks superstructure
Construction Breadth
Schedule Comparison
Fewer beams to place
Typical floor original: 222 members
Typical floor redesign: 127 members
Fewer columns and foundations
16 columns removed in redesign
30% reduction in structure construction time
Original Design
20 days foundations
9 weeks superstructure
Redesign
14 days foundations
6 ½ weeks superstructure
Structural Option
John M Sekel

24. Presentation Overview
Existing Building
Proposal
Structural Redesign
Construction Considerations
Architecture Redesign
Mechanical Considerations
Conclusions
Structural Option
John M Sekel

25. Architectural Breadth
Reflect change in floor framing
Square box-like windows
Long, continuous windows
Structural Option
John M Sekel

26. Architectural Breadth
Increase glazing
Emphasize the drum
Vertically spanning glass
Structural Option
John M Sekel

27. Architectural Breadth
Structural Option
John M Sekel

28. Architectural Breadth
Structural Option
John M Sekel

29. Architectural Breadth
Structural Option
John M Sekel

30. Architectural Breadth
Structural Option
John M Sekel

31. Presentation Overview
Existing Building
Proposal
Structural Redesign
Construction Considerations
Architecture Redesign
Mechanical Considerations
Conclusions
Structural Option
John M Sekel

32. Mechanical Breadth Increase in cooling load
Greater glazing area on facade
Carrier hourly analysis program analysis
Additional 1.5 tons of cooling required per floor
Original system capacity is 92 tons per floor
1.6% increase
Most likely will not need to resize equipment
Further analysis required
Structural Option
John M Sekel

33. Presentation Overview
Existing Building
Proposal
Structural Redesign
Construction Considerations
Architecture Redesign
Mechanical Considerations
Conclusions
Structural Option
John M Sekel

34. Conclusions Insignificant cost difference by implementing new system
Shorter construction time
Faster cost return
Improvement to building architecture
Greater tenant flexibility with interior spaces
Good selling point for owner
More notable exterior façade
Final Recommendation:
Use re-designed structural system
Structural Option
John M Sekel

35. Thank You Structural Design Group LF Jennings AE Faculty and staff
Mike Weiss
LF Jennings
Kevin Malpass
AE Faculty and staff
Prof. Parfitt, Dr. Geschwinder, Dr. Hanagan
AE classmates
Chris Flynn, Tim Nolan
My parents and roommates for their encouragement and support
Structural Option
John M Sekel

36. Questions? ? ? ? ? ?
Structural Option
John M Sekel

37. Structural Depth Building Height Comparison Structural Option
John M Sekel

38. Structural Depth Plenum heights 11 ¾” increase per floor
5’-10 ½” total building height increase
Structural Option
John M Sekel

39. Structural depth Plenum comparison Typical In-Bay Framing Member
Deepest Member at Duct Crossing
Required Plenum Depth
Original Design
W14x22 [17] 1”
W18
46 ¾”
New Design
W24x55 [48] 1 ¼”
W30
58 ½”
Structural Option
John M Sekel

40. Structural Depth
Deflections and camber
Structural Option
John M Sekel

41. Structural Depth
Connections
Structural Option
John M Sekel

42. Structural Depth Drift Frame Drift Ratio #1 1.77” 1/583 #2 1.49” 1/693#3
1.44”
1/717 #4
2.43”
1/425
Structural Option
John M Sekel

43. Structural Depth Drift Frame #1 Frame #2 Frame #3 Frame #4 Level Drift
Ratio 2
0.290”
1/662
0.219”
1/877
0.226”
1/850
0.371”
1/518 3
0.288”
1/583
0.268”
1/627
0.270”
1/622
0.386”
1/435 4
0.299”
1/562
0.265”
1/634
0.260”
1/646
0.414”
1/406 5
0.295”
1/570
0.254”
1/661
0.244”
1/689
0.415”
1/405 6
0.292”
1/575
0.240”
1/700
0.224”
1/750
0.411”
1/409 R
0.302”
1/616
0.238”
1/782
0.212”
0.430”
1/433
Structural Option
John M Sekel

44. Construction Breadth Working crews
RS Means assumes a steel crew of the following:
(2) Steel foremen
(5) Steel workers
(1) Welder
(1) Welding machine
(1) Oiler operator
(1) Crane operator
(1) 90 ton crane
The daily operating cost for this crew is $
Structural Option
John M Sekel

45. Construction Breadth Crane reach 60 ton crane 4 ton pick at 60’
W21X182 frame column
Structural Option
John M Sekel

46. Construction Breadth Project delivery system Structural Option
John M Sekel

47. Construction Breadth Linear footage comparison
Original structure: 43,300 feet
Redesigned structure: 32,700 feet
Additional cost is hidden in fabrication and materials
Structural Option
John M Sekel