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AE Senior Thesis 2009 U.S. Pharmacopeia Headquarters Consolidation Rockville, MD

AE Senior Thesis 2009 U.S. Pharmacopeia Headquarters Consolidation Rockville, MD. Analysis and Design of a Mild Reinforced One way slab with Post Tensioned Beams. Jeffrey L. Rothermel Jr. The Pennsylvania State University Department of Architectural Engineering Structural Option.

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AE Senior Thesis 2009 U.S. Pharmacopeia Headquarters Consolidation Rockville, MD

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  1. AE Senior Thesis 2009 U.S. Pharmacopeia Headquarters Consolidation Rockville, MD Analysis and Design of a Mild Reinforced One way slab with Post Tensioned Beams Jeffrey L. Rothermel Jr. The Pennsylvania State University Department of Architectural Engineering Structural Option

  2. Discussion Topics • Background Information • Existing Structure • Design Goals • Project Stages and Process • Structural Design • Mechanical Ductwork Redesign AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  3. U.S. Pharmacopeia Headquarters • Owner: U.S. Pharmacopeia • Architect: Hellmuth, Obata + Kassabaum (HOK) • Structural: Cagley & Associates Inc. • MEP: R.G. Vanderweil Engineers • Construction: DPR Construction Inc. • 6 stories - 91’ • 191,000 ft2 of new office and lab space • New 19,000 ft2 conference center • Houses chemical and biological labs • $69 million AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  4. U.S. Pharmacopeia Headquarters • Showcase laboratory spaces • Large open office plans • Kitchenettes for employees at every floor • Curtain wall, metal paneling, and beige split face CMU • Conical auditorium with curtain wall skin • Enclosed outdoor plaza space AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  5. Existing Conditions • Two way mild reinforced concrete • flat slab with drop panels • 22’x22’ column grid • 14’ floor-to-floor heights (Typ.) • Reinforced concrete moment frames • Steel framed conference center • Truncated, conical concrete auditorium Photo courtesy of HOK Inc. Photo courtesy of HOK Inc. Photo courtesy of HOK Inc. AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  6. AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  7. Design Goals • Lower floor-to-floor heights from 14’ to 13’ • Increase column grid from 22’ to 44’ • Eliminate moment frames • Reduce ductwork sizes • Maintain existing ceiling height AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  8. Design Stages • Investigate 3 alternatives • Choose optimum system • Design chosen floor system • Design matching lateral system • Resize ductwork mains AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  9. Possible Solutions Taken From AISC Design Guide 14: Staggered Steel Truss Framing Staggered Steel Truss system Two way post tensioned slab One way slab with post tensioned beams AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  10. Structural Depth Design Design Process • Lay out beams • Design slab system • Design post tensioned beams • Size • Tendon quantity • Drape • Column check • Design shear walls • Shear reinforcement • Flexural reinforcement • Coupling beams AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  11. One way slab with PT beam design New Beam Layout AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  12. One way slab with PT beam design • Slab Design • One way reinforcing • 7” slab typ. • 7-1/2” slab at 250 psf loading • #5 bars T&B • #5@ 24” for shrinkage and temperature parallel to beams AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  13. One way slab with PT beam design Designed with RAM Concept per ACI 318-02 • Spans extended to 44’ • Shallow wide beams • Existing column size kept (24”x24”) • F’c = 6000 psi • Class T Transitional • T-Beam properties • #6 Bottom at ρmin= 0.004 • #5 Top with no minimum reinforcement • 0.6f’ci compression limit (18.4.1(a)) • 7.5√f’c ≤ft ≤ 12√f’c tensile stress limit (18.3.3) AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  14. One way slab with PT beam design Design Process Size the beams Add tendons Check stresses Adjust profile Schedule AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  15. One way slab with PT beam design • Interior beams typically 48”x14” • Edge beams typically 30”,32”x14” • 40-60 tendons interior typically • 30-40 tendons in edge typically AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  16. One way slab with PT beam design • Transfer Girders • 16-30” deep at transfers • 48-56” wide at transfers • Same depth as existing transfers • 20-50% more post tensioning AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  17. One way slab with PT beam design Load Balancing • Balance % of dead load • Target balance 60-90% • Target met in most beams • A few beams overbalanced • Some underbalanced AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  18. One way slab with PT beam design • Existing Column Properties • Checked using PCA Column • Moments from RAM Concept at column • Interior columns sufficient • Exterior columns require increased rebar • Required for increased moment • 8#9 12#9 AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  19. Shear Wall Design Existing reinforced concrete moment frames AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  20. Shear Wall Design AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  21. Shear Wall Design Load Determination • Method 2 per ASCE 7-05 • 4 wind cases investigated • Seismic loads using Equivalent Lateral Force Method • 18” trial thickness • 1.6W vs. 1.0E Taken From ASCE 7-05 AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  22. Shear Wall Design • Shear reinforcement as required per Sec. 11.9 • Each wall/segment designed for shear and flexure separately • Minimum shear reinforcing used • None needed for shear strength • #4s H,V @18” Typ. • Moment controlled reinforcing designs • #8s Vert. for flexure AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  23. Shear Wall Design • Deflections in SAP • 8” Membrane • Self mass included • 24” mesh • Full I values for all members • F’c = 3000 psi • Wind limitation H/400 • Seismic limitation 0.02hxn AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  24. Shear Wall Design • Coupled shear wall design • SAP • Member self weight included • 8” Membrane • Coupling beams extend into wall face • 2’ Rigid end offset • 48” deep beams • Coupling beams as deep beams • per Sec. 21.9.7 • Designed per Sec. 10.7 • Shear reinforcement per Sec. 11.7 AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  25. Mechanical Ductwork design • Design Goals • Keep loss under .25” WC/100’ • Keep fpm flow under 2500 in mains over occupied spaces • Reduce height and increase width AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  26. Mechanical Ductwork Redesign First Floor AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  27. Mechanical Ductwork Redesign • Vertical mains shrunk 8-20” per side • Maximum horizontal run that travels under beams is 20” • Minimum ceiling height is 8’10” • Average ceiling height can be +10’6” AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  28. Some Quick Costs • Savings on façade and ductwork • More expense on structure AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  29. Project Summary • Post tensioned beam system provides optimal performance • Wide shallow beams incorporate desired attributes into floors • 48”x14” for most interior beams and 30”x14” for most exterior • 8” shear walls designed for moment • Mechanical ductwork redesigned to obtain project goals • Savings on façade and mechanical ducts, more cost in structure • All goals reasonably attained AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

  30. Questions/Comments AE Senior Thesis 2009|U.S. Pharmacopeia Headquarters|Jeffrey L. Rothermel Jr.|Structural Option

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