Peggy Ryan Williams Center AE Senior Thesis April 14, 2014 Angela - PowerPoint PPT Presentation

Peggy Ryan Williams Center AE Senior Thesis April 14, 2014 Angela Mincemoyer Structural Option Advisor | Dr. Boothby Ithaca, New York

Peggy Ryan Williams Center  Introduction AE Senior Thesis  Proposal April 14, 2014  Structural Depth  Gravity System Angela Mincemoyer  Lateral System Structural Option  Bridge Truss  Architectural Breadth Advisor | Dr. Boothby  Lighting Breadth  Conclusion Ithaca, New York

Peggy Ryan Williams Center  Introduction  Proposal Owner | Ithaca College Architect | Holt Architects  Structural Depth Structural Engineer | Ryan-Biggs Associates  Gravity System  Lateral System 58,200 GSF  Bridge Truss 4 Stories Substantial Completion | March 2010  Architectural Breadth Photo provided courtesy of Holt Architects  Lighting Breadth  Conclusion Introduction

Peggy Ryan Williams Center  Introduction Composite steel floor  Proposal 3” x 20 gauge composite metal deck 6” concrete slab  Structural Depth 48’  Gravity System Wide Flange Beams, girder, columns  Lateral System Irregular Layout  Bridge Truss Geometry, cantilevers  Architectural Breadth  Lighting Breadth  Conclusion Existing Gravity System

Peggy Ryan Williams Center  Introduction  Proposal Concentrically braced structural steel frames North-South  Structural Depth East-West  Gravity System Seismic Design Category A  Lateral System Wind Controlled Design  Bridge Truss  Architectural Breadth  Lighting Breadth  Conclusion Existing Lateral System

Peggy Ryan Williams Center  Introduction  Proposal Pratt Trusses  Structural Depth HSS  Gravity System 3.5” pipe  Lateral System Double Cantilever  Bridge Truss  Architectural Breadth  Lighting Breadth  Conclusion Existing Bridge System

Peggy Ryan Williams Center Scenario | Project Schedule is no longer critical Scenario | Learning opportunity  Introduction  Proposal Proposal | One way concrete slab system with Proposal | Two different redesign options will pan joists and girders be considered  Structural Depth  Beneficial for cantilevers  Reflection of New York’s  Gravity System historic covered bridges  Accommodates varying spans  Lateral System  Reflect on original name of & geometries  Bridge Truss the building  Thinner slab  Architectural Breadth (“The Gateway Building”)  Minimize architectural impact  Lighting Breadth  Conclusion Building Bridge

Peggy Ryan Williams Center Scenario | Project Schedule is no longer critical Scenario | Learning opportunity  Introduction  Proposal Proposal | One way concrete slab system with Proposal | Two different redesign options will pan joists and girders be considered  Structural Depth  Beneficial for cantilevers  Reflection of New York’s  Gravity System historic covered bridges  Accommodates varying spans  Lateral System  Reflect on original name of & geometries  Bridge Truss the building  Thinner slab  Architectural Breadth (“The Gateway Building”)  Minimize architectural impact  Lighting Breadth  Conclusion Building Bridge

Peggy Ryan Williams Center Proposal| One way concrete slab system with Proposal| Two different redesign options will  Introduction pan joists and girders be considered  Proposal Goals| Design a one way concrete slab system Goals| After considering two redesign options:  Structural Depth  Determine which option to while:  Gravity System move forward with  Minimizing floor system depth  Lateral System  Design one side truss of the  Minimizing architectural impact  Bridge Truss bridge  Architectural Breadth  Lighting Breadth  Conclusion Building Bridge

Peggy Ryan Williams Center Proposal| One way concrete slab system with Proposal| Two different redesign options will  Introduction pan joists and girders be considered  Proposal Goals| Design a one way concrete slab system Goals| After considering two redesign options:  Structural Depth  Determine which option to while:  Gravity System move forward with  Minimizing floor system depth  Lateral System  Design one side truss of the  Minimizing architectural impact  Bridge Truss bridge  Architectural Breadth  Lighting Breadth  Conclusion Building Bridge

Peggy Ryan Williams Center  Introduction  CRSI Manual  Proposal  Same joist size and spacing used throughout  Structural Depth  2 worst case spans considered  Gravity System  30” forms with 6” rib @ 36” o.c.  Lateral System  20” rib depth + 4.5” slab = 24.5” system depth  Bridge Truss  f ’c = 4,000 psi  Architectural Breadth  fy = 60 ksi  Lighting Breadth  Conclusion Pan Joist System

 8 Designed members indicated Peggy Ryan Williams Center D  Chosen due to: Long spans,  Introduction large tributary widths, high loadings  Proposal  Designed using spBeam  Strength requirements 2  Structural Depth  Deflections checked per ACI 318-11  Gravity System Table 9.5b 13  Lateral System  Bridge Truss  Architectural Breadth  Lighting Breadth Column Line D Column Line 2 Column Line 13 Column Line 8  Conclusion Framing Plan Girders/Beams

Peggy Ryan Williams Center  Designed using spColumn  Introduction  Both axial loads from above & moments were  Proposal applied  Structural Depth  Square section chosen  Gravity System  Ease of construction  Lateral System  Aid in future lateral system design  Bridge Truss  All column sizes were increased to  Architectural Breadth 18”x 18” for constructability  Lighting Breadth  Conclusion Columns

Peggy Ryan Williams Center  Introduction  Proposal  Columns & girders were removed from  Structural Depth original design  Gravity System  Floor system depth decreased by 5- 5/8”  Lateral System  Larger floor-to-ceiling height  Bridge Truss  Architectural Breadth  Lighting Breadth  Conclusion Summary Existing Redesign

Peggy Ryan Williams Center  Current lateral system  Introduction  Concentrically braced structural steel frames  Proposal  No longer the best option  Structural Depth  Gravity system may double as the lateral system  Gravity System  Concrete moment frames in North-South and  Lateral System East-West directions  Bridge Truss  4 concrete moment frames were considered in  Architectural Breadth each direction  Lighting Breadth  Conclusion Lateral System Introduction

Peggy Ryan Williams Center  Both wind and seismic forces were calculated per ASCE7-10  Introduction  Wind controlled  Proposal  Using spColumn , 18”x18” columns were  Structural Depth designed  Gravity System  Biaxial bending was considered  Lateral System  Worst case girder and joist were checked for  Bridge Truss beam-column interaction  Architectural Breadth  Found to be adequate  Lighting Breadth  Conclusion Lateral System Analysis

Peggy Ryan Williams Center  Introduction  Analysis was done using 4 frames in both  Proposal directions  Structural Depth  By adding frames the system will surely be  Gravity System adequate   Lateral System The gravity system of the building doubles as the lateral system  Bridge Truss  Architectural Breadth  Lighting Breadth  Conclusion Summary

Peggy Ryan Williams Center  Introduction  Sketches were produced to determine which  Proposal inspiration would be used in the redesign  Structural Depth  The covered bridge option was chosen  Gravity System  Box truss design  Lateral System  Move supports out to open up the space  Bridge Truss  Warren Truss  Architectural Breadth  Lighting Breadth  Conclusion Bridge Introduction

Peggy Ryan Williams Center  Introduction  Only gravity loads were considered for the side  Proposal trusses  Structural Depth  Panel point loads were determined based on layout  Gravity System   Lateral System Controlling Load Combinations:   Bridge Truss 1.2 D + 1.6 L + 0.5 S   Architectural Breadth 1.2 D + 1.6 S + L  Lighting Breadth  Conclusion Loads

Peggy Ryan Williams Center 1.2 D + 1.6 L + 0.5 S  Indexing Method  Introduction  Loading all panel points  Proposal  Produced worst case force in top chord,  Structural Depth bottom chord, and far left diagonal  Gravity System  Use of geometry to determine member forces  Lateral System  Method of Joints to verify Indexing Method  Bridge Truss forces   Architectural Breadth Indexing Method is an accurate method of analysis  Lighting Breadth  Conclusion Member Force Determination

Peggy Ryan Williams Center  Introduction  Proposal  Steel Manual Tables  Structural Depth  Table 4-4 for top chord and diagonal  Gravity System compression members  Lateral System  Table 5-5 for bottom chord tension member Top Chord: HSS7x7x¼  Bridge Truss Bottom Chord: HSS7x7x¼  Architectural Breadth Diagonals: HSS4x4x½  Lighting Breadth  Conclusion Member Design