1. Duquesne University Forbes Expansion
The Pennsylvania State University Spring Semester 2007
Michael Szott
Structural Option
Senior Thesis Presentation
Duquesne University Forbes Expansion
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

2. Presentation Outline Introduction Proposed Analysis
Structural Depth Study
Lateral system redesign
Gravity system redesign
Breadth Studies
Acoustics
Construction cost comparison
Conclusions and Recommendations
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

3. Location Michael J. Szott Structural Option
Duquesne University Multipurpose Facility

4. Location Michael J. Szott Structural Option
Duquesne University Multipurpose Facility

5. Project Overview Project Team Duquesne University DRS Architects
Jendoco Construction
Atlantic Engineering Services
Dodson Engineering
Hornfeck Electrical
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

6. Project Overview Building Statistics Construction dates
March 2006 – December 2007/January2008
Building occupancy
Mixed Use – retail, student fitness, office, entertainment
Building size
7 stories – 125,000 sq. ft.
Project cost
$24 million
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

7. Project Overview Existing Structural System Gravity system
Composite steel construction
Lateral system
Concentrically braced frames
Foundations
Auger cast piles
Grade Beams
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

8. Project Overview Typical – Floors 1-3 Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

9. Project Overview Long Span Framing, Floors 4-5 Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

10. Proposed Analysis Lateral Resisting System
More efficient bracing scheme?
Gravity System – Vibration Analysis
Intermixed activity spaces
Long span conditions
Interior Acoustical Performance
Impact on Construction Cost
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

11. Structural Depth: Lateral Redesign
Lateral Bracing Locations
Typical Frame
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

12. Structural Depth: Lateral Redesign
Three Alternate Bracing Schemes
Modified concentric bracing
Chevron bracing
Alternating diagonals (K-bracing)
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

13. Structural Depth: Lateral Redesign
Design Criteria
IBC 2003
ASCE 7-02
Applied Loads
Dead
Live
Snow
Wind
Seismic
IBC2003 section :
“analysis must be performed except when structures are assigned to Seismic Design Category A”
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

14. Structural Depth: Lateral Redesign
Individual Frames: RAM Advanse
Optimization
Minimal Weight
Member check
Local Buckling
Overall System: RAM Frame
Drift check
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

15. Structural Depth: Lateral Redesign
Modified – Tension/Compression
Chevron Bracing
“K” Bracing
Existing - Tension Only
LC: DL+0.75LL+0.75W
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

16. Structural Depth: Lateral Redesign
Existing Frame Design
HSS 6x4x1/4 – 8x4x5/8
Columns: W14x53 – 132
Beams: W33x118
Modified Ten. – Comp.
HSS 4x3x1/4 – 9x7x1/4
Columns: W14x53 – 211
Beams: W33x118
Chevron Bracing
HSS 4x3x1/4 – 10x8x3/8
Columns: W14x53 – 211
Beams: W24x76
“K” Bracing
HSS 4x3x1/4 – 12x10x1/2
Columns: W10x45 – W24x131
Beams: W33x118
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

17. Structural Depth: Lateral Redesign
Chevron Bracing
Least weight of all systems
Smallest frame beams
Controlling deflection limits – L/600 or 0.3”
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

18. Structural Depth: Lateral Redesign
Bracing Layout HR IR
5th
H/400
Existing
5.6
3.3
2.1
3.96
X-Bracing (T/C)
4.6
2.6
1.5
Chevron Bracing
4.8
2.7
K-Bracing 5
2.9
1.6
Overall Building Drift (in.)
Drift at High Roof Level
Drift at Intermediate Roof Level
Drift at 5th Floor Level
Pedestrian bridge
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

19. Structural Depth: Gravity Redesign
Vibration Design: AISC Design Guide 11
Floor vibrations due to human activity
Criteria based on rhythmic activity
Aerobics
Dining and Dancing
Serviceability issue – not strength
Design to avoid personal discomfort
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

20. Structural Depth: Gravity Redesign
Four Critical Spaces Analyzed
2nd floor Aerobic/Fitness areas
3rd floor gymnasium (typical bays)
4th floor gymnasium (long spans)
5th floor ballroom (long spans)
Designed for partially loaded bays
Modified constant “k” used
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

21. Structural Depth: Gravity Redesign
Acceleration Limits
Dancing/Dining g
Aerobics only g
Gymnasium g-0.15g
(i.e. basketball, etc…)
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

22. Structural Depth: Gravity Redesign
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

23. Structural Depth: Gravity Redesign
Existing Fitness Framing
20’8” span
Beams: 7’ o.c.
Girders: W16x31 (21’0”)
31’4” span
Beams: 7’ o.c.
Girders: W18x35 (21’0”)
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

24. Structural Depth: Gravity Redesign
New Fitness Framing
31’4” span
Beams: 7’ o.c.
Girders: W21x83 (21’0”)
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

25. Structural Depth: Gravity Redesign
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

26. Structural Depth: Gravity Redesign
Existing Ballroom Framing
79’6” span
Beams: 7’ o.c.
Girders: W27x84 (21’0”)
Criteria not met
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

27. Structural Depth: Gravity Redesign
Ballroom Redesign
Departure from Design Guide 11
Partial loading vs. Fully loaded bays
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

28. Structural Depth: Gravity Redesign
New Ballroom Framing
Conventional
Beams: 7’ o.c.
Girders: W30x90 (21’0”)
Castellated Beams
Modified wide flange sections
Lighter and more stiff
Economical
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

29. Structural Depth: Gravity Redesign
Castellated Ballroom Framing
79’6” span
Beams: 7’ o.c.
Girders: W27x84 (21’0”)
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

30. Structural Depth: Gravity Redesign
Overall Effects of New Framing
Lighter gravity system
Reduced clear height in both gym spaces
Improved vibrational performance
Cost?
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

31. Breadth Study: Construction Cost
Castellated Sections
Less material, reduced material cost
2 man hours to convert from wide flange to castellated
“…in general, spans longer than 40’ can recoup these costs.”
- Billy Milligan, VP of CMC Steel Products
Delivery
From Hope, AR
Distance: miles
Cost: $65,500
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

32. Breadth Study: Construction Cost
Material savings, greater than fabrication costs
Delivery costs drive more expensive system
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

33. Breadth Study: Construction Cost
Lateral Frames
Structural tubing more expensive than wide flange sections
Fabrication and connection costs
Chevrons bracing: least material = least cost
Frame beams considerably smaller
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

34. Conclusions and Recommendations
A chevron bracing scheme offers a reduction in weight and material
Redesigning the lateral system will save on material costs
Castellated beams improve floor vibrations and decrease floor weight over long spans
Gravity system costs increase slightly
Suggested improvements are cost feasible
Michael J. Szott
Structural Option
Duquesne University Multipurpose Facility

35. Questions?? ?? Michael J. Szott Structural Option
Duquesne University Multipurpose Facility