Duquesne University Forbes Expansion The Pennsylvania State University Spring Semester 2007 Michael Szott Structural Option Senior Thesis Presentation Duquesne University Forbes Expansion Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Presentation Outline Introduction Proposed Analysis Structural Depth Study Lateral system redesign Gravity system redesign Breadth Studies Acoustics Construction cost comparison Conclusions and Recommendations Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Location Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Location Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Project Overview Project Team Duquesne University DRS Architects Jendoco Construction Atlantic Engineering Services Dodson Engineering Hornfeck Electrical Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Project Overview Building Statistics Construction dates March 2006 – December 2007/January2008 Building occupancy Mixed Use – retail, student fitness, office, entertainment Building size 7 stories – 125,000 sq. ft. Project cost $24 million Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Project Overview Existing Structural System Gravity system Composite steel construction Lateral system Concentrically braced frames Foundations Auger cast piles Grade Beams Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Project Overview Typical – Floors 1-3 Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Project Overview Long Span Framing, Floors 4-5 Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Proposed Analysis Lateral Resisting System More efficient bracing scheme? Gravity System – Vibration Analysis Intermixed activity spaces Long span conditions Interior Acoustical Performance Impact on Construction Cost Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Lateral Bracing Locations Typical Frame Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Three Alternate Bracing Schemes Modified concentric bracing Chevron bracing Alternating diagonals (K-bracing) Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Design Criteria IBC 2003 ASCE 7-02 Applied Loads Dead Live Snow Wind Seismic IBC2003 section 1616.6 : “analysis must be performed except when structures are assigned to Seismic Design Category A” Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Individual Frames: RAM Advanse Optimization Minimal Weight Member check Local Buckling Overall System: RAM Frame Drift check Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Modified – Tension/Compression Chevron Bracing “K” Bracing Existing - Tension Only LC: DL+0.75LL+0.75W Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Existing Frame Design HSS 6x4x1/4 – 8x4x5/8 Columns: W14x53 – 132 Beams: W33x118 Modified Ten. – Comp. HSS 4x3x1/4 – 9x7x1/4 Columns: W14x53 – 211 Beams: W33x118 Chevron Bracing HSS 4x3x1/4 – 10x8x3/8 Columns: W14x53 – 211 Beams: W24x76 “K” Bracing HSS 4x3x1/4 – 12x10x1/2 Columns: W10x45 – W24x131 Beams: W33x118 Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Chevron Bracing Least weight of all systems Smallest frame beams Controlling deflection limits – L/600 or 0.3” Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Lateral Redesign Bracing Layout Drift @ HR Drift @ IR Drift @ 5th H/400 Existing 5.6 3.3 2.1 3.96 X-Bracing (T/C) 4.6 2.6 1.5 Chevron Bracing 4.8 2.7 K-Bracing 5 2.9 1.6 Overall Building Drift (in.) Drift at High Roof Level Drift at Intermediate Roof Level Drift at 5th Floor Level Pedestrian bridge Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Vibration Design: AISC Design Guide 11 Floor vibrations due to human activity Criteria based on rhythmic activity Aerobics Dining and Dancing Serviceability issue – not strength Design to avoid personal discomfort Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Four Critical Spaces Analyzed 2nd floor Aerobic/Fitness areas 3rd floor gymnasium (typical bays) 4th floor gymnasium (long spans) 5th floor ballroom (long spans) Designed for partially loaded bays Modified constant “k” used Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Acceleration Limits Dancing/Dining 0.02g Aerobics only 0.06g Gymnasium 0.10g-0.15g (i.e. basketball, etc…) Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Existing Fitness Framing 20’8” span Beams: W12x16 @ 7’ o.c. Girders: W16x31 (21’0”) 31’4” span Beams: W18x40 @ 7’ o.c. Girders: W18x35 (21’0”) Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign New Fitness Framing 31’4” span Beams: W21x83 @ 7’ o.c. Girders: W21x83 (21’0”) Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Existing Ballroom Framing 79’6” span Beams: W36x210 @ 7’ o.c. Girders: W27x84 (21’0”) Criteria not met Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Ballroom Redesign Departure from Design Guide 11 Partial loading vs. Fully loaded bays Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign New Ballroom Framing Conventional Beams: W40x372 @ 7’ o.c. Girders: W30x90 (21’0”) Castellated Beams Modified wide flange sections Lighter and more stiff Economical Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Castellated Ballroom Framing 79’6” span Beams: CB50x221 @ 7’ o.c. Girders: W27x84 (21’0”) Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Structural Depth: Gravity Redesign Overall Effects of New Framing Lighter gravity system Reduced clear height in both gym spaces Improved vibrational performance Cost? Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Breadth Study: Construction Cost Castellated Sections Less material, reduced material cost 2 man hours to convert from wide flange to castellated “…in general, spans longer than 40’ can recoup these costs.” - Billy Milligan, VP of CMC Steel Products Delivery From Hope, AR Distance: 1015 miles Cost: $65,500 Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Breadth Study: Construction Cost Material savings, greater than fabrication costs Delivery costs drive more expensive system Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Breadth Study: Construction Cost Lateral Frames Structural tubing more expensive than wide flange sections Fabrication and connection costs Chevrons bracing: least material = least cost Frame beams considerably smaller Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Conclusions and Recommendations A chevron bracing scheme offers a reduction in weight and material Redesigning the lateral system will save on material costs Castellated beams improve floor vibrations and decrease floor weight over long spans Gravity system costs increase slightly Suggested improvements are cost feasible Michael J. Szott Structural Option Duquesne University Multipurpose Facility

Questions?? ?? Michael J. Szott Structural Option Duquesne University Multipurpose Facility