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National Science Foundation Funded Research: NEESR-CR: Enabling Performance-Based Seismic

Design of Multi-Story Cold-Formed Steel Structures (CFS-NEES)

Presentation for

AISI Committee on Framing Standards - Lateral AISI Committee on Specifications – Seismic

February 2011

•! Who: A collaborative research team centered at Johns Hopkins and lead by the PI: Ben Schafer, includes Naru Nakata, Steve Buonopane, Rob Madsen, collaborators, students, visiting scholars

•! What: A $923,000 NSF-funded research effort, plus experimental funding enabled by the help of the American Iron and Steel Institute

•! Where: Primarily at Johns Hopkins University, and utilizing the NEES testing facility at the University of Buffalo

•! When: Over the next 3 years

•! Why: To enable engineers to practice true seismic performance-based design of CFS buildings and to spur innovation in the seismic design of CFS systems

•! How: Through a combined computational and experimental plan to develop new knowledge and analysis tools culminating in full-scale testing of a two-story cold-formed steel framed building.

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Project Team CFS-NEES Project Team Ben Schafer PI Naru Nakata coPI Steve Buonopane coPI Rob Madsen Sr. Personnel Kara Peterman Exp. GRA Jiazhen Leng Comp. GRA Darren Saulsbury, Jr. HS Res. Andrew Faulkner JHU Undergrad International and Domestic Collaborators Deniz Ayhan JHU Vis. Stud. Qiu Guozhi JHU Vis. Scholar Peng Liu JHU Vis. Stud. Colin Rogers McGill Collab. Cheng Yu UNT Collab. Cris Moen V. Tech Matt Eatherton V. Tech !

Industry Coordination Bonnie Manley AISI Industry Liaison Don Allen SSMA, SFA, CFSEI George Frater CSCC (Canada) Rick Haws IAB Member Tom Castle IAB Member Kelly Cobeen IAB Member Randy Daudet IAB Member Steve Tipping IAB Member Jay Parr IAB Member Renato Camporese IAB Member

CFS Seismic Design Today •! We have neither the modeling capabilities, nor the

experimental understanding to complete a reliable seismic evaluation of CFS framed structures without relying on grossly conservative methodologies.

•! We cannot model fundamentally important phenomenon, such as local buckling in the analysis tools currently used for inelastic time history analysis

•! We know precious little about CFS interactions sub-systems: stud-to-track, joist-to-rim, systems: gravity and shear walls, floors, roofs, multi-story combined systems: LFRS vs. gravity vs. non-load bearing whole buildings

This project aims to set a new path for CFS seismic design to address these issues and enable true

performance-based seismic design

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Research Activities Summary

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high fidelity FE

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photo credit NEESWood

sub-system testing

cold-formed steel Frame FE

Research Activities Summary

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EXP

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More detailed mapping of CFS-NEES Computational modeling

Experimental High fidelity High efficiencyComponent stud, joist, track AISI-COMP, (1) (1) CM(D)-1Sub-systems stud-to-track / joist-to-rim EXP-1 CM(A)-2a, (1) CM(D)-2a stud-to-wall / joist-to-floor (1) CM(A)-2b, (1) CM(D)-2bSystems gravity walls (1) (1) (1) shear walls EXP-UNT, (2) CM(A)-3a (2) floor/roof diaphragms (3) CM(A)-3b CM(D)-4aSystem interactions gravity and shear walls EXP-2 CM(A)-3c CM(D)-4b walls with diaphragms EXP-3 CM(A)-3d CM(D)-4c multi-story walls EXP-McGill, (5) CM(A)-3e (5)Multi-story Building LFRS only FSB-4a FSB-7 FSB-6 All Structural FSB-4b FSB-7 FSB-6 Whole Building FSB-4c - FSB-6 Incremental Dynamic Analysis - - IDA(1) Prior research by PI Schafer et al. see proposal sections 6.1.1 and 6.2.1(2) Prior research by Int'l. Collaborator Rogers et al. see proposal section 6.1.2(3) Prior research in cold-formed steel literature see proposal section 6.1.3 (4) This note not utilized in this version of this table (see proposal for original version)(5) NSERC research of Rogers on multi-story shear walls

Figure 1 Schematic of proposed testing (a) sub-system tests of EXP-1, and system interaction testing of (b) a wall line with gravity and shear walls, EXP-2, and (c) a shear wall with floor detailing included, EXP-3

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more on sub-system testing sub-system testing in the JHU lab

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more on full-scale testing

full-scale shaking

at the Buffalo NEES facility

Multi-story CFS building (Architectural only)

elevation

exploded isometric

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Advisory Board •! Renato Camporese, P.E., S.E. LEED AP

Read Jones Christoffersen Ltd. •! Thomas A. Castle, S.E.

Ficcadenti Waggoner & Castle Consulting Structural Engineers •! Kelly Cobeen, S.E.

Wiss, Janney, Elstner Associates, Inc. •! L. Randy Daudet, P.E.

Simpson Strong-Tie •! Richard B. Haws, P.E.

NUCONSteel Commercial Corp. •! Jay Parr, P.E.

Dietrich Design Group •! Steven B Tipping

Tipping Mar & Associates

Ledger Framing

Detail provided by Tipping Mar

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Ledger Framing

Picture provided by Don Allen

Summary •! NSF funding for NEESWood was $1.4 million. For the first

time CFS is in the game with $923,000 for CFS-NEES and also a $400,000 CAREER grant for Cheng Yu

•! The “R” factor game that has been the heart of simplified seismic design is coming to an end as we know it and CFS currently lacks fundamental tools to leverage new methods

•! Wood and other materials are developing new seismic resisting systems and CFS needs to play catch up here

•! CFS-NEES represents a significant opportunity for the industry to regain its natural technical advantage, and to provide the enabling tools for modern earthquake engineering analysis, and the fundamental knowledge to leverage the true performance of our system

•! AISI’s involvement intellectually and financially is crucial to the project’s success. I look forward to working with you.

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Supplementary: UB-NEES Facility

Supplementary: Gantt Chart

2010-2011 2011-2012 2012-2013Su Fa Sp Su Fa Sp Su Fa Sp

Experimental TasksEXP-1: Joist-to-rim testsEXP-2: Shear wall with gravity wall testEXP-3: Shear wall with floor testEXP-McGill: Multi-story shear wall test tests detailed to prototype buildingEXP-4: Multi-story building test prototype building design UB-NEESComputational Modeling TasksCM-1: OpenSees thin-walled frame elementCM-2: Phenomenological connection elementsCM-3: High fidelity wall and diaphragm modelsCM-4: Reduced order wall and diaphragm modelsCM-5: High fidelity whole building modelsCM-6: Reduced order whole building modelsCM-7: Incremental Dynamic Analysis performed with increasing sophistication