nees without borders

NEES 7TH ANNUAL MEETINGSeismic Mitigation in a Flat World

NEES WITHOUT BORDERS

Corrugated Sheet Steel Shear Walls

Corrugated Sheet Steel Shear Wall

• Corrugated metal deck

• Metal studs

• Screws

•

Type II Construction

•

Off the shelf components

•

Bearing Wall System

•

Light-Framed Cold-formed Steel Framing

Promising Applications

•

Multi-unit Residential

•

Dormitories

•

Hotels / Motels

•

Retail / Commercial

•

Penthouses

•

Seismic retrofit

The Wave of The Future

- Shop assembled

- Easily transported

- Standardized

- Improved quality

- Faster construction

- BIM ready

Pre-fabricated

Structural Systems

Conventional Lateral Systems

•

Steel Tension only Flat Straps

•

Steel Frames

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Concrete Block

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Proprietary Wall Board

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Proprietary Braced Panels

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Flat Steel Sheets

A lateral system that is:

The Missing link…

-

Non-combustible

- Light

- Strong

- Durable

- Economical

The Solution…

Corrugated Sheet Steel Shear Walls

Research Program:

•

Funded by the Charles Pankow

Foundation

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Testing at the University of California, Berkeley

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Principal Investigator, Bozidar

Stojadinovic

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Project Champion, Steven Tipping, SE

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Non-Proprietary

44 Wall Specimens Tested

20, 18, 16 and 14ga

Primary Test Variables:

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Metal stud gauge

22, 20, and 18ga

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Corrugated Sheathing

#10, #12 and #14

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Self-tapping Screws

4’-0”

x 8’-2”

Specimen Types:

•

Typical Panel

2’-0”

x 8’-2”

•

Narrow Panel

•

Component Variables3 specimens w/ sheetrock

2 specimens double-sided

2 specimens w/ 4”

dia. holes

2 specimens w/ 2”x4”

holes

Test Apparatus

Panel Frame

Actuator Connection

Frame Base

Panel Connection at Base

Panel Connection at Top

Loading Protocol

• Follows ICC-ES AC154 • Full-reversal cyclic shear loading, 74 cycles to 5% drift• Frequency = .2 cycle per second

Dis

plac

emen

t

Cycles

Force-Displacement Curve for Typical Panel

Video Not Available

Video Not Available

Failure Sequence:

1.

Screw gouging stud/decking

2.

Tension field warping of decking

3.

Tension failure of screw

Screw Gouging of Decking

Tension Field Warping of Deck

Tension Failure of Screw

Failure Locations

Top Right

Bottom Right

Horizontal Seam

Negligible Effects due to Small Openings

Testing Summary:

•

Gypsum wallboard does not increase strength

•

Small openings are O.K.

•

No seam blocking required

•

Double sided = double strength

•

3x stronger than equivalent plywood sheathed panel

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2x stronger than equivalent proprietary panel

•

Strong, stiff, predictable behavior

Specimen #9 Force-Displacement Curve

(18 gauge decking, 16 gauge studs, #12 @ 3”

oc)

Group #14 Backbone Curve (18 ga. decking, 16 ga. studs, #12 @ 3”

oc)

Group Summary of Backbone Curves

PLYWOODON WOOD

STUDS

STEEL SHEETS

PLYWOOD ONMETAL STUDS

FLAT STRAP

Steel SCBFR=6, Cd=5

Corrugated Metal Decking Shear Wall Design Table

Panel Assembly20 ga. studs 18 ga. studs 16 ga. studs

#12 Screws #12 Screws #12 Screws #14 Screws

Sheathing Screw Spacing

Shear(plf)

Shear(plf)

Shear(plf)

Shear(plf)

22 ga. deck6”

o.c. 1,173 1,505 1,836 ---

3”

o.c. --- 3,050 3,290 ---

18 ga. deck 3”

o.c. --- 4,144 5,164 5,874

Nominal Shear Capacities for Wind and Seismic Forces for Shear Walls Framed with Cold Formed Steel Studs Sheathed with Corrugated Metal Decking

Determining Seismic Response Parameters: R, Ω, Cd

•

Traditional approach per 1999 SEAOC Blue Book/2000 NEHRP commentary

•

Proposed Approach: ATC 63

ASCE 7-05 Table 12.2-1 Traditional Approach

Design Coefficients and Factors for Seismic Force Resisting Systems

Light-Framed Walls SheathedWith Wood Or Steel Sheets

6.5 3 4

Light-Framed Walls With Corrugated Sheet Steel 5.5* 2.5* 3.25*

Light-Framed WallsWith Flat Straps 4 2 3.5Light-Framed WallsWith Other Materials 2 2.5 2

R Wo Cd

*Proposed

Corrugated Metal Decking Shear Wall Design TableTraditional Approach

Panel Assembly20 ga. studs 18 ga. studs 16 ga. studs

#12 Screws #12 Screws #12 Screws #14 Screws

Sheathing Screw Spacing

Shear(plf)

Shear(plf)

Shear(plf)

Shear(plf)

22 ga. deck6”

o.c. 469 602 734 ---

3”

o.c. --- 1,220 1,316 ---

18 ga. deck 3”

o.c. --- 1,658 2,065 2,350

Allowable Shear Capacities for Wind and Seismic Forces for Shear

Walls Framed with Cold Formed Steel Studs and Sheathed with Corrugated Metal Decking (R

=5.5, Cd

=3.25)

ATC 63 Approach

Anticipated seismic response factors for light-framed walls sheathed with:

WoodR = 6 Ω

= 3 Cd

= 4

Corrugated Sheet SteelR = 5 Ω

= 2.5 Cd

= 3.25

Next StepsAdditional Wall Testing:

•

8 x 8 shear panels

•

Fire testing of assemblies

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Acoustical testing of assemblies

Code Adoption:

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ATC 63 peer review

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BSSC and ASCE 7 code committee approvals

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Final IBC structural classification

Download report:

•

FTP site: ftp.tippingmar.com

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Username: metalwall

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Password: screw