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F.W. Olin Center

F.W. Olin Center. Redesign of Structural Floor System with Emphasis on Vibration. Daniel Chwastyk – Structural Option. Thesis Presentation 2004. Presentation Outline. Existing building features Proposal and basis for proposal Redesign of floor framing Considerations raised by redesign

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F.W. Olin Center

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  1. F.W. Olin Center Redesign of Structural Floor System with Emphasis on Vibration Daniel Chwastyk – Structural Option Thesis Presentation 2004

  2. Presentation Outline • Existing building features • Proposal and basis for proposal • Redesign of floor framing • Considerations raised by redesign • Vibration check of floors • CM / Lighting Breadths • Conclusion

  3. Existing building features

  4. Existing Building Features • Owner:Union College • Architects / Primary Engineers:The Kostecky Group • General Contractor:G.C. Pike • Site Utilities:Friedman Fisher Associates, P.C. • Landscape Architects:The LA Group

  5. Existing Building Features • Uses • 5 Story multi-use technology building • Science Center of Union College Size • 53,640 s.f. • $7.4 million dollar cost Architecture • 2 relatively symmetrical wings flanking a circular rotunda • Exterior – combination of earth and engineered materials

  6. Existing building features Foundation • Continuous spread footings • Column footings under the few steel columns Structural • K-joist framing system • Non-composite steel system in several key rooms • CMU load bearing walls • Elevated floors are 3” concrete slab on form decking

  7. Existing building features Lateral System • CMU shear walls • Seismic forces control • Base shear – 833 kips • Forces distributed based on the stiffness of the shear walls • Shear wall A was checked for strength 2262 psi (135.7 kips/60 in2) < 2500 psi

  8. Proposal Vibration Vibration Vibration WEIGHT COST

  9. Floor Comparison Composite Steel System Non Composite Steel System Concrete Pan Joist System One Way Concrete System

  10. Floor Comparison Weight • One Way Concrete System (2.64 klf) • Concrete Pan Joist System (2.16 klf) • Non Composite Steel System (1.94 klf) • Composite Steel System (1.66 klf)

  11. Floor Comparison • One Way Concrete System • Concrete Pan Joist System • Composite Steel System • Non Composite Steel System Other factors??

  12. Redesign of Floor System • Applicable Code – IBC 2000 • Steel designed using ASCI Steel Design Manual • Live Loads • Taken from shop drawings • Dead Loads • Actual weight of steel and floor and 25 psi super-imposed load • Floor • 3” concrete • 20 Gauge UFX 36 form decking • 6x6 10/10 WWF

  13. Redesign Of Floor System • Initial redesign based on gravity load • Beams were checked for deflection, and moment and shear capacities • Beams rest on 7 ½” x 7 ½” x ¾” bearing plates

  14. Redesign Of Floor System • Cost considerations • Repetition of members • Availibility?? • Didn’t use any beams smaller than W 10

  15. Redesign Of Floor System • Weight of Building • 10,000 kips original • 13,000 kips with new floor system • Checks needed due to weight increase • Shear • Foundations • Wall load

  16. Braced Frames Reason for Investigation? Construction Time Design: Based on existing member sizes as well as a few calculations Check: Deflections of Frame C & D were checked in STAAD Maximum Deflection = 1.213”

  17. Braced Frames Conclusions???

  18. Vibration Check of Floors • Design guide 11 • Natural frequencies ( π → 1.4 π ) • Max allowable vibration for sensitive equipment • Δp – Deflection of the floor at midspan due to a 0.225 kip load • Moderate paced walking assumed: Uv = 5.5 kip*Hz2 Δp / fn ≤ V / Uv

  19. Vibration Check of Floors Δp / fn ≤ V / Uv What to do????? Options to lower vibrations • Increase Member Size • Decrease Member Spacing • Require lower walking speed • Place sensitive equipment not at midspan

  20. Vibration Check of Floors Laboratories needed to be redesigned Δp / fn ≤ V / Uv Pl3 ½ 96EI π/2 386EI 3.64 E-4 wl4

  21. Vibration Check of Floors Telescope Room Design • Room was already designed with steel members, so a check is necessary • Telescope is permanently placed and sits atop two W 16x40 beams spaced 2 feet apart • Slow walking can be assumed in the confined area Vibrational velocity for this area = 86.4 µ in./sec

  22. Cost Comparison Estimate created using ICE 2000 • Labor, Material and Equipment costs Increase of $90,934 Compared to $7.7 million building cost??

  23. Lighting Breadth Second floor computer classroom lighting was altered. Done to… • Reduce to glare on the computers • Possibly lower the electrical load and costs • Existing fixtures: • 4 rows of recessed lensed troffers • 32 Watt T8 fluorescent lamps • (4 per fixture)

  24. Lighting Breadth New fixture: Indirect/direct with 32 Watt fluorescent lamps Power density = 1.276 Watts Lightscape model

  25. Conclusions • Vibrations were reduced • Costs increased slightly • Recommendation • The alternative framing system seems to be more beneficial in the F.W. Olin Center than the original system

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