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Allison Lamb Structural Emphasis April 16, 2003

New Science Center. Lateral System Redesign. Allison Lamb Structural Emphasis April 16, 2003. Presentation Outline. Background Existing Structural Proposal Redesign Other Considerations Fire Protection Acoustical Recommendations. Background. Project Team Owner

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Allison Lamb Structural Emphasis April 16, 2003

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  1. New Science Center Lateral System Redesign Allison Lamb Structural Emphasis April 16, 2003

  2. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  3. Background • Project Team • Owner • Pennsylvania System of Higher Education • Architect • Stv Architects • Engineer • Stv Incorporated Kutztown University New Science Center

  4. Background • Delivery Method • Design – Bid – Build • Dates of Construction • 3/18/02 – 10/3/04 • Several Phase Project • Addition • 3/18/02 – Present • Overall Cost • $16 million • Addition Cost • $11.4 million Kutztown University New Science Center

  5. Background • Location • Kutztown University campus • Berks County, Pennsylvania • Building Function • Academic Building • Science Departments • Classrooms, Labs, Offices Kutztown University New Science Center

  6. Background • Architecture • Brick facade • Large glass Atrium • Floor Layout • Red – offices • Green – Classrooms • Blue – Labs • Magenta – Vertical circulation • Yellow – Storage/building systems • Black – atrium space First Floor Second Floor Third Floor Fourth Floor Kutztown University New Science Center

  7. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  8. Existing Structural • Gravity System • Composite Framing • 5 in. Concrete • 1 ½ in. composite metal deck • 50 ksi Steel beams and girders • 50 ksi Steel columns • Roof Framing • Roof joists • 50 ksi beams and girders Kutztown University New Science Center

  9. Existing Structural • Lateral System • Steel moment frames • 2 in E-W Direction • 2 In N-S direction • Typical Connection Kutztown University New Science Center

  10. Existing Structural • Foundations • 4000 psi concrete • rock bearing drilled piers with grade beams in the unexcavated portion of the building • spread footings in the basement portion Kutztown University New Science Center

  11. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  12. Proposal • Replace current lateral system • Redesign Criteria • lateral force resisting system must: • be designed to resist the lateral loads • perform to the required serviceability criteria under the design loads • lateral force resisting system must not: • compromise the architectural aesthetics and functionality of the building’s spaces • disrupt the other building systems • be prohibitively expensive Kutztown University New Science Center

  13. Proposal • Alternative #1 • incorporate braced frames into the structure • Alternative #2 • create several frames with partially restrained connections • Alternative #3 • some combination of braced frames and partially restrained frames Kutztown University New Science Center

  14. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  15. Redesign • Gravity System • Realign columns into grid system for more options • Resize members using RAM • Check flexure, shear, deflection, composite action • Smaller member sizes • Second Floor Vibration Issue • Leave second floor member sizes unchanged Original Layout New Layout Kutztown University New Science Center

  16. Redesign • Lateral System • Alternative #1 – Braced Frames • typical placement • Architectural repercussions • Add a column Kutztown University New Science Center

  17. Redesign • Alternative #2 – PR Frames • Use several frames and take advantage of the stiffness in the PR connections Kutztown University New Science Center

  18. Redesign • Alternative #3 • Use braced frames in East – West direction and PR Frames in North – South Direction Kutztown University New Science Center

  19. Redesign • Braced Frames • Initial member sizes determined by gravity requirements • Checked with Ram using ASCE 7-95 lateral loads • Members increased to meet strength requirements Kutztown University New Science Center

  20. Redesign • Frames modeled in STAAD to determine stiffness • ASCE 7-98 Lateral Loads distributed by rigidity • Member sizes increased to meet strength and stiffness requirements under lateral loads including torsion Kutztown University New Science Center

  21. Redesign • Drift due to wind limited to H/400 • Allowable 1.875” • Actual 1.406” • Drift due to seismic limited to 2% of the story height below Kutztown University New Science Center

  22. Redesign • Final member sizes • Columns - W14x109 • Beams - W30x90 • Braces - 2L5x5x7/8 Kutztown University New Science Center

  23. Redesign • PR Frames • Method of Flexible wind connections or type 2 with wind (ASD) • Beams designed as simple beams • Columns designed to provide frame stability • connections designed to resist the factored lateral loads and have sufficient ductility to accommodate the rotations Kutztown University New Science Center

  24. Redesign • Initial member sizes determined by flexible moment connection method • frames modeled in STAAD as FR and stiffness determined • Lateral Loads redistributed by rigidity • Member sizes increased to provide adequate strength and stiffness requirements Kutztown University New Science Center

  25. Redesign • Drift determined as per conservative British Wind-Moment Approach • Drift determined using FR connections, then multiplied by 1.5 to account for actual PR connections • Wind drift limited to H/400 • Allowable total drift = 1.875” • Actual total drift = 1.220” • Seismic Drift limited to 2 inches Kutztown University New Science Center

  26. Redesign • Final Member sizes • Beams W30x99 • Columns W14x145 • Connection • Double Web Angle Top and Bottom Seat • Designed to resist shear • Moment-Rotation Characteristics determined • Typical connection Kutztown University New Science Center

  27. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  28. Other Considerations • Foundations • Changing layout of frames, adding additional columns and relocating columns • Redesign for bearing, shear, and overturning • Architectural • New column layout changes room sizes slightly Kutztown University New Science Center

  29. Other Considerations • Mechanical System • Changing some room sizes will affect the mechanical load for those spaces • Lighting System • Room size changes will affect the lighting layout Kutztown University New Science Center

  30. Other Considerations • Cost Comparison • Gravity System • Redesign = total savings of $72,596.67 • Lateral System • PR Frames = increase of $23,696.66 • Braced Frames = Savings of $54,633.43 Kutztown University New Science Center

  31. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  32. Fire Protection • Automatic wet sprinkler protection to provide 100% protection coverage • IBC 2000 Code Requirements • Business Group B occupancy type • Type IB construction Kutztown University New Science Center

  33. Fire Protection • Floor Construction • UL Design No. D902 • 4.5” concrete min. • Spray applied fire resistive materials • None required for floor • 1-1/16” inch to the beams and girders Kutztown University New Science Center

  34. Fire Protection • Columns • UL Design No. X501 • Spray Applied Fire resistive materials • 1 3/8” coating • Glass Fiber Gauze • 2 1/16” coats Kutztown University New Science Center

  35. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  36. Acoustical • 300 seat auditorium/lecture hall • Room Size • 109 ft3 per person • Preferred range 80–150 ft3 per person • Room Shape • Sloped 5˚ • Best sloped 7˚ or more Kutztown University New Science Center

  37. Acoustical • Room Materials • Red - Gypsum Board • Blue - Fabric-Wrapped acoustical panels • Magenta - Acoustical ceiling tile • Yellow - Wooden chair rail • Green - Pinch-pleated drapery Kutztown University New Science Center

  38. Acoustical • Reverberation Times • Calculation using sound absorption properties of materials • Optimal - less than 0.8s from 250 to 4000 Hz Kutztown University New Science Center

  39. Presentation Outline • Background • Existing Structural • Proposal • Redesign • Other Considerations • Fire Protection • Acoustical • Recommendations Kutztown University New Science Center

  40. Recommendations • Gravity System • Consider redesigned member sizes but verify vibration requirements • Lateral System • Use braced frames in the east-West direction • Use original moment frames in North-South Direction • Fire Protection • Choose system to meet minimum code requirements • Acoustical • Consider increasing the slope of the room Kutztown University New Science Center

  41. acknowledgements Thank you Stu Rothenberger of STV Architects for all of the information that made thesis possible All of my Friends and Family especially Mike, I couldn’t have done this without you The AE Faculty for their expertise and help Happy Birthday to me Kutztown University New Science Center

  42. Questions Any Questions? Kutztown University New Science Center

  43. Background • Mechanical System • Variable Volume System • 8 AHUs handling 146,275 CFM • Lab Spaces • Once Through Air • Humidified • Other Spaces – 50% Outside Air, 50% Recirculated • 650 Ton Chiller • 650 Ton Cooling Tower • Natural gas fired 143 HP Boiler Kutztown University New Science Center

  44. Background • Lighting System • Interior lighting provided by fluorescent lighting fixtures • auditorium/lecture hall has fluorescent fixtures for normal lighting and 75 watt incandescent fixtures for dimming • controlled by local switches throughout the building • Exit and emergency lighting connected to the emergency distribution system • exterior building lighting consists of metal halide fixtures Kutztown University New Science Center

  45. Background • Electrical System • Splice into existing13.2kV campus distribution feeder • Interior unit substation transforms voltage to 208/120 volt service • main power distribution is a 208/120 volt, 3 phase, 4 wire system • emergency and standby power provided by a natural-gas-fired engine generator Kutztown University New Science Center

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