PLAZA AT PPL CENTER Allentown PA Economical Design

PLAZA AT PPL CENTER Allentown, PA Economical Design Considerations for Steel Construction Amy S. Graver - Structural Option Spring 2003 Senior Thesis

INTRODUCTION PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Re-Design § Conclusions Plaza at PPL Center Amy S. Graver - Structural

INTRODUCTION PROJECT TEAM § Owner: Liberty Property Trust § Primary Tenant: PPL Energy. Plus § Architect and Landscape: Robert A. M. Stern Architects § Structural Engineers: Thornton-Tomasetti § MEP, Fire Protection: PPL Energy Services Mid-Atlantic, LCC § Construction Manager: L. F. Driscoll § Architect of Record: Kendall/Heaton Associates, Inc. § Civil Engineers: Pennoni Associates § Lighting Consultant: Quentin Thomas Associates, Inc. Plaza at PPL Center Amy S. Graver - Structural

INTRODUCTION LOCATION LINDEN STREET NORTH N. NINTH STREET N. TENTH STREET BUILDING N. EIGHTH STREET PROPOSED PARKING GARAGE TOWER AT PLAZA AT PPL CENTER HAMILTON STREET Plaza at PPL Center HAMILTON STREET Amy S. Graver - Structural

INTRODUCTION BUILDING FACTS Size § $29 million base building cost, $19 million tenant specific costs § 256, 000 sq. ft. § 200, 000 sq. ft. to be leased by PPL Corporation Uses § 8 -story Multi-use Building § First Floor: Retail Space § Floors 2 -6: Office Space for PPL Energy. Plus § Floors 7 -8: Energy Securities Trading Floors Plaza at PPL Center Amy S. Graver - Structural

INTRODUCTION BUILDING FACTS Architecture § LEED Gold Certification § Central Atrium § Winter Gardens and Roof Top Garden § Glass Façade with Strips of Pre-cast Concrete Panels Plaza at PPL Center Amy S. Graver - Structural

INTRODUCTION STRUCTURE Foundation § Partial Basement w/ Poured Concrete Walls § Continuous Concrete Spread Footings Gravity System § Composite Steel Beams § Composite Deck § 14’-20’ Stories § 30’x 42’ Bays § Typical Sizes § Beams: W 18 § Columns: W 14 Plaza at PPL Center Amy S. Graver - Structural

INTRODUCTION STRUCTURE Lateral System § North-South: East-West: Moment Braced. Frames A B C Moment Frames B/C D Moment Frame A Moment Frame D Plaza at PPL Center Amy S. Graver - Structural

ECONOMY PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Implications § Conclusions Plaza at PPL Center Amy S. Graver - Structural

ECONOMY CONSIDERATIONS % of Construction Costs § Low Seismic Design § Braced Frames % of Construction Costs § Partial Composite Construction Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Re-Design § Conclusions Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS SEISMIC DESIGN Allentown, PA § Not Considered a High Seismic Area § Seismic Design Category B Under More Recent Codes § Seismic Can Control § Subject to Seismic Provisions when R>3 Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS SEISMIC DESIGN Ductility § Lower Base Shear with Increased Ductility Response Modification Factor § To account for ductility of a system § Cs is indirectly proportional to R § Since V= Cs. W, a lower R-Factor corresponds to a higher base shear Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS SEISMIC DESIGN Applied Code: IBC 2000 § References AISC Seismic Provisions & Supplement 1 § Connections must be designed by Seismic Provisions if R>3 AISC Seismic Provisions for Structural Steel Buildings § Connections must be stronger than connected members § Classifies moment frames based on a rotation criteria Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS DESIGN STATEMENT Connection Response Four Required Types Rotation Modification of Moment Capacity Frames Factor per FEMA AISC 350 § Special Moment Frames (SMF) R=8 Mp θ=0. 4 radians 1. 1 Ry. Mp § Intermediate Moment Frames (IMF ) R=6 Mp θ=0. 2 radians 1. 1 Ry. Mp § Ordinary Moment Frames (OMF) R=4 1. 1 Ry. Mp None 1. 1 Ry. Mp § Steel Systems not Detailed for Seismic Resistance R=3 Mu Plaza at PPL Center None Mu Amy S. Graver - Structural

MOMENT FRAME COMPARISONS DESIGN STATEMENT Comparison Plaza at PPL Center Faster Construction More Economical Smaller Connections § R=3 Results Larger Members § OMF Less Stringent Detailing § IMF Decreasing R-Factor § SMF Increasing Base Shear Differences Amy S. Graver - Structural

MOMENT FRAME COMPARISONS CONNECTIONS Connection Web-Bolted, Design Flange-Bolted Connections § Approved forrotation Seismic Use FEMA 350: criteria § SMF & IMF § Tested by Federal Emergency § LRFD Manual: strength design Management Agency (FEMA) § OMF & R=3 § Meets Rotation Requirements for SMF and IMF Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS COST COMPARISON Included Costs § Material Costs § Fabrication Labor § Erection Labor Excluded Costs § Quality Inspection § Special Fabrication Procedures Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS CONNECTION COMPARISON Moment Frame A Design Capacity of Members Actual Loads Smaller SMF Members Heavier Columns R=3 Plaza at PPL Center W 18 x 60 W 14 x 99 Deeper Beams W 14 x 74 Strong Column, Weak Beam W 24 x 62 Amy S. Graver - Structural

MOMENT FRAME COMPARISONS COMPARISON Plaza at PPL Center Amy S. Graver - Structural

MOMENT FRAME COMPARISONS SCHEDULE EFFECTS 1000 hrs. of Fabrication Time § Cost of Stiffeners § Saves 3 weeks § Critical Path § Added Float § Start Later Erection 3 weeks § Remains on Critical Path § Dependent on Sitework and Foundation Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME ANALYSIS PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Re-Design § Conclusions Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME DESIGN STATEMENT Results of the Moment Frame Comparison § Low Seismic is More Economical § Connections Drive Cost Try Braced Frames in East-West Direction § Eliminates 410 Moment Connections § Works Within the Proposed Floor Plan Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME DESIGN ARCHITECTURE Chevron Tenant Try Braced Fitout Braced Frames § Rooms Adequate along for Proposed Openings § column 14’ Minimum grids Floor-to-floor Height §§ Accommodates 30 -year lease a Double Door Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME DESIGN FLOOR PLANS Proposed Braced Frames Existing Moment Frames Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME DESIGN Seismic is the Governing Lateral Force for Members § Concentric Braced Frame § R=3 § V=1182 K Typical Sizes § W 14 Columns and Braces to Match North-South Direction § W 24 x 68 Beams Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME DESIGN COST COMPARISON Included Costs § Moment frame members now sized for gravity only § Additional cost of connections above a typical shear connection Plaza at PPL Center Amy S. Graver - Structural

BRACED FRAME DESIGN SCHEDULE Additional Time Savings Project Complete: April 30, 2003 § Fabrication § Not on the critical path § Adds 3 weeks of float § Erection Project Complete: April 12, 2003 § On the critical path § Project Completion: 3 weeks earlier Plaza at PPL Center Amy S. Graver - Structural

COMPOSITE FLOOR EVALUATION PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Re-Design § Conclusions Plaza at PPL Center Amy S. Graver - Structural

COMPOSITE CONSTRUCTION DESIGN STATEMENT Cost of 1 Shear Stud = 10 lbs. of Steel § $0. 50 Material Cost § $1. 50 Labor Cost Try Partial Composite § Is a heavier beam with fewer shear studs more economical? Plaza at PPL Center Amy S. Graver - Structural

COMPOSITE CONSTRUCTION FLOOR PLANS Floors 2 -6 Existing: 100% Composite Re-design: 90% Composite W 18 x 35 [48] W 18 x 35 [44] Plaza at PPL Center Amy S. Graver - Structural

COMPOSITE CONSTRUCTION FLOOR PLANS Floors 1, 7 -8 Existing: 100% Composite Re-design: 40% Composite W 18 x 40 [48] W 21 x 44 [24] Plaza at PPL Center Amy S. Graver - Structural

COMPOSITE CONSTRUCTION COMPARISON Total Building Savings Plaza at PPL Center Amy S. Graver - Structural

MECHANICAL RE-DESIGN PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Re-Design § Conclusions Plaza at PPL Center Amy S. Graver - Structural

MECHANICAL EFFECTS DESIGN STATEMENT Composite Beam Comparison § W 18 to W 21 § 3” decrease in usable ceiling plenum Original Design § 28”x 12” SA duct below beams § Air Flow Rate = 2500 CFM § Air Velocity = 1150 FPM § Static Pressure Drop = 0. 1 in. w. g. Plaza at PPL Center Amy S. Graver - Structural

MECHANICAL EFFECTS RE-DESIGN Initial Size Problems § 9” duct height is required to maintain existing plenum § To supply 2500 CFM at 0. 1 in. w. g. , § 42”x 9” required § Does not meet the 4 -to-1 width-to-height ratio Plaza at PPL Center Amy S. Graver - Structural

MECHANICAL EFFECTS SOLUTION Design § 2500 CFM First 16’ § 1900 CFM Past Branch 34”x 9” 42”x 9” Results § Turning Vanes in Elbow § 4 -to-1 Ratio past Branch 600 CFM VAV Box § Maintains Design Criteria Plaza at PPL Center Amy S. Graver - Structural

MECHANICAL RE-DESIGN PRESENTATION OUTLINE § Introduction § Economical Design Considerations § Moment Frame Comparisons § Braced Frame Design § Composite Floor Evaluation § Mechanical Re-Design § Conclusions Plaza at PPL Center Amy S. Graver - Structural

CONCLUSIONS ECONOMY Cost Savings § Moment Frames with R=3. . . $22, 000 § Braced Frames. . . $100, 000 § Composite Construction. . . $5, 300 Time Savings § Moment Frames with R=3. . . Fabrication: 3 weeks § Braced Frames. . . Fabrication: 6 weeks. . . Erection: 3 weeks Plaza at PPL Center Amy S. Graver - Structural

CONCLUSIONS RECOMMENDATIONS Braced Frames are Most Economical Lateral System § Feasible with architectural layout § $100, 000 cost savings § Project Completion: 3 weeks earlier Deeper, Heavier Beams with Less Composite Action § Increases floor depth § Ceiling plenum height retained with shallower duct Plaza at PPL Center Amy S. Graver - Structural

CONCLUSIONS ACKNOWLEDGMENTS A huge thank you to everyone who answered questions, provided information and offered support… your time and efforts are greatly appreciated. Pennoni Associates: Civil Engineer AE Faculty § Frank Adams, P. E. , AIA § Dr. Hanagan, P. E. § Jeff Ott, P. E. § Walt Schneider, P. E. § Ed Sander, P. E. § Professor Parfitt, P. E. § The Adams Division § Jonathan Dougherty Thornton-Tomasetti: Structural Engineer § Hi Sun Choi, P. E. L. F. Driscoll: Construction Manager § Ed Jackowski Stewart-Amos Steel AE Class of 2003 § Rebecca Mittel § Melissa Rosol My Family and Friends § Last but certainly not least… § Curt Zeigler Plaza at PPL Center Amy S. Graver - Structural

CONCLUSIONS QUESTIONS Plaza at PPL Center ? Amy S. Graver - Structural

CONCLUSIONS QUESTIONS Plaza at PPL Center ? Amy S. Graver - Structural

MECHANICAL EFFECTS RESULTS § Higher Air Velocity to Maintain Air Flow Rate § Increased noise through diffusers § Not a large enough increase to impact occupants § Duct meets industry standard for 4 -to-1 ratio Plaza at PPL Center Amy S. Graver - Structural