1. Engineering Research Center Development of a Seismic Design Methodology for Precast Floor Diaphragms – An Overview Robert Fleischman, UA Clay Naito and Richard Sause, LU Jose Restrepo and Andre Filiatrault, UCSD S.K. Ghosh, S.K. Ghosh Associates, Inc.

2. Engineering Research Center PCI National Convention October 2003 History PCI and University Consortium created: –Diaphragm Seismic Design Methodology (DSDM) Task Group –Industry Advisory Panel –Producer Member Partners ($91,000 in specimen donations) PCI R&D Committee distributed a Request for Proposal (RFP) in October 2002. Arizona-Lehigh-UCSD Consortium awarded grant from PCI for $200,000 in December 2002.

3. Engineering Research Center PCI National Convention October 2003 History (con’t) Initial DSDM Research Meeting held at PCI Headquarters, Chicago August 6, 2003. Proposal submitted to National Science Foundation (NSF) Grant Opportunities for Academic Liaison with Industry (GOALI) Program February 7, 2003. DSDM Consortium awarded GOALI grant from NSF for $467,406 in August 2003. Official Start Date - October 2003 – 3 year duration

4. Engineering Research Center PCI National Convention October 2003 DSDM Consortium DSDM Task Group PCI, IAP

5. Engineering Research Center PCI National Convention October 2003 Research Objective Develop a Seismic Design Methodology for Precast Concrete Diaphragms Design Force Patterns Internal Force Calculations Reinforcement Capacities Stiffness Calculations Flexibility Limits Structural Integrity Details

6. Engineering Research Center PCI National Convention October 2003 To be jointly determined by DSDM Task Group and University Consortium, based on need and resources: Topped and Pretopped Diaphragms Hollow Core and Double Tees Precast Units Scope of Research Low to High Seismic Zones Wall and Frame Structural Systems Existing and Promising Reinforcement Details Panel Joints, Beam Interfaces, Wall/Frame Anchorages, Topping/Precast Unit Bond

7. Engineering Research Center PCI National Convention October 2003 Research Approach: Integrated Analysis and Experimentation UA Analyses link UCSD structure tests with LU detail tests.

8. Engineering Research Center PCI National Convention October 2003 DSDM Task Group S.K.Ghosh DSDM Task Group Chair President, S. K. Ghosh Associates R. Becker Vice President Spancrete Industries, Inc. N. Cleland President Blue Ridge Design, Inc. Tom D’Arcy President Consulting Engineers Group N. Hawkins Professor Emeritus Univ. of Illinois Paul Johal Research Director PCI Joe Maffei Engineering Consultant Rutherford & Chekene Engineers Susie Nakaki President The Nakaki Bashaw Group, Inc. Help to guide the physical scope –Selection of prototype structures and candidate details –Involvement with transformation of research results into an appropriate design methodology

9. Engineering Research Center PCI National Convention October 2003 DSDM Task Group Activities Oversight –Review and approve research program –Regularly evaluate research direction Physical scope –Select portfolio of prototype structures –Select set of reinforcement details: existing, promising –Design of prototype structures Interface to design practice –Evaluate existing code –Gain consensus on approach to design methodology –Transfer of research into practice and codes

10. Engineering Research Center PCI National Convention October 2003 Industry Advisory Panel Organized to provide broad industry input to the project Includes precast producers, designers, and academics Facilitate aligning of research with existing and future efforts Participate semi-annually at Committee Days and PCI National Convention

11. Engineering Research Center PCI National Convention October 2003 Producer Members Blakeslee Prestress, Inc. High Concrete Structures Precast/Prestressed Concrete Manufacturers Association of California Spancrete, Inc. Tindall-Virginia

12. Engineering Research Center PCI National Convention October 2003 DSDM Research Project Three initial tasks were identified in RM#1 as keys to guiding the scope of the research: 1.A general consensus on the form and intent of the design methodology 2.A portfolio of prototype structures 3.A set of reinforcing detail candidates Research Meeting #1

13. Engineering Research Center PCI National Convention October 2003 Objectives 1.Establish consensus on a design philosophy to guide research DSDM Research Meeting #1 Applicability of Design/Analysis Methods: Beam Analogy, Strut & Tie; Stringer-Panel Hollow Core details, emerging techniques and emphasis Role of Elastic Diaphragm Design and Need for Detailing for Ductility in High, Moderate, Low Seismic Zones Role of Web Reinforcement: compliance vs. ductility Applicability of construction methods: composite, non-composite, pretopped

14. Engineering Research Center PCI National Convention October 2003 Template for Design Procedure Diaphragm Design Methodology ResearcherNakakiRodriguez/ Restrepo Farrow/ Fleischman/ Sauce NEHRP Appdx. Design Force Approach Design to LFRS Ultimate Use R Factor on 1 st mode only  is function of diaphragm flexibility Higher factor for untopped Design Force   = 2.8  i = ~2   = 1.0-3.0   PROPOSED APPROACH: Calibrate  through research. Overstrength Factors (  For certain conditions, an overstrength factor is needed for elastic diaphragm response in the design earthquake Tradeoff exists between  and the ductility and drift demand in a severe seismic event

15. Engineering Research Center PCI National Convention October 2003 Classify diaphragms to give the designer flexibility to choose between a higher design force or special details. Diaphragm Classification (DC) DesignationSeismic Zones OrdinaryODA,B,C IntermediateIDB,C,D,E SpecialSDD,E,F Precast Diaphragm classifications in terms of detailing requirements. Template for Design Procedure Diaphragm Design Methodology

16. Engineering Research Center PCI National Convention October 2003 Prescribe different overstrength depending on zone, span and choice of reinforcing details Seismic Design Category Diaphragm Span ABCDEF L cl <L fd DC OD ID SDIDSD  px  ** **  ee ** ee L cl >L fd DC ODIDODID SD  px  ee ** ee ** ee Applicability of diaphragms for different zones, forces and spans. Template for Design Procedure Diaphragm Design Methodology

17. Engineering Research Center PCI National Convention October 2003 Qualification standards/prequalify reinforcing details for use with the appropriate diaphragm classification: ClassificationODIDSD Reinforcement  detailing   Collector0.75  regular 0.6 special Chord0.9  regular 0.9 special WebShear0.75   0.6  Tension  Type A  Type B  Type C Detailing requirements for each classification Template for Design Procedure Diaphragm Design Methodology

18. Engineering Research Center PCI National Convention October 2003 Realistic designs for study Different classes of structures to explore diaphragm response A template for selecting test specimens A common benchmark to: evaluate different details integrate research between the academic institutions evaluate economic and construction factors (IAP) Trial structures to formulate the design methodology Objectives 2.Develop Portfolio of Prototype Structures to guide research on precast diaphragms DSDM Research Meeting #1

19. Engineering Research Center PCI National Convention October 2003 The Prototype Structure Portfolio should include designs that are representative of: Both typical but also challenging construction Double tee and Hollow core precast units Topped and Untopped floor systems Low and High Seismic Zone designs Construction practice across the country Wall and frame lateral systems of interior and exterior layout, and varying heights Various floor plans including squat, long and irregular Prototype Structure Portfolio

20. Engineering Research Center PCI National Convention October 2003 Prototype Structure Candidates Candidate #1: East coast parking structure 3-bay parking structure central ramp 300’ x 181’ 12’x60’ DTs untopped pour strip over precast beams

21. Engineering Research Center PCI National Convention October 2003 Internal precast walls along the ramp Prototype Structure Candidates East coast parking structure (con’t)

22. Engineering Research Center PCI National Convention October 2003 3 story 163’x136’ Interior shear walls; Perimeter frames 4’x27’ HC Interior beams Prototype Structure Candidates Candidate #2: West Coast Office Building

23. Engineering Research Center PCI National Convention October 2003 5 story, 91’ x 253’ plan 4’ x 15-25’ HC Masonry Bearing wall Prototype Structure Candidates Candidate #3: West Coast Residential

24. Engineering Research Center PCI National Convention October 2003 9-story 2- bay 220’ x 122’ plan 10’x60’ DT Internal precast beam Prototype Structure Candidates Candidate #4: West Coast Parking Structure

25. Engineering Research Center PCI National Convention October 2003 8 story structure: 70'x220‘ in plan Shear walls in the short direction Moment frames in the long direction Post-tensioned flat plate – investigate a precast alternative Prototype Structure Candidates Candidate #5: West Coast Hotel

26. Engineering Research Center PCI National Convention October 2003 Prototype Precast Structures Candidates for Portfolio Coverage of Parameters

27. Engineering Research Center PCI National Convention October 2003 Objectives 3.Establish candidate reinforcing details for use in analytical and experimental research DSDM Research Meeting #1 Determine candidates based on existing research and industry feedback Questionnaire Available at: http://www.atlss.lehigh.edu/cjn3/PCI/PCIconnections.htm

28. Engineering Research Center PCI National Convention October 2003 Feedback from Industry Double-Tee Panel-to-Panel Connections DC4 : JVI Connector DC3 :Topping with Connectors DC7 :Bent Rebar Connector DC8-A :Plate and Rebar Connector DC8-D1, DC8-B : (Bent ) Stud Type with Inclined Plate DC9-A, 9-B,10, 11-A, 11-B: Welded Cover Plate Type

29. Engineering Research Center PCI National Convention October 2003 Feedback from Industry HC1 : Grouted shear key HC2 : Slab edge serration below shear key HC3 : Reinforced steel across longitudinal joints HC4 : Embedded Steel plates with a welded steel plate cover across longitudinal joints Hollow-core Panel-to-Panel Connections

30. Engineering Research Center PCI National Convention October 2003 Upcoming Research Activities UA – Trial Analyses of Prototype Diaphragms –Basic behavior –Identify Critical Regions –Approximate performance requirements LU –Phase 1 Detail Tests –Design and Fabricate Test Setup –Commence Phase 1 Test UCSD – Structural Level Examinations –Design Shake Table Experiment –Investigate Dynamic Performance of Prototype Structures

31. Engineering Research Center PCI National Convention October 2003 We are grateful to PCI, producer members, and the industry participants for their strong support of this research. We look forward to a fruitful research project culminating in a new seismic design methodology for precast diaphragms.