Blast-Resistant Testing for Massive Timber Exterior Wall: Expanding Timber Opportunities In North America November 2015 – Mass Timber Workshop

B-15-91.1

© 2015 Karagozian & Case, Inc.

Karagozian & Case, Inc. 700 N. Brand Blvd. Glendale, CA 91203 818-240-1919 www.kcse.com WoodWorks – Wood Products Council www.woodworks.org University of Maine Orono, ME 04469 www.umaine.edu

By: Lisa Podesto, P.E. (WW) Dr. Edwin Nagy, Ph.D., P.E., S.E. (UMaine) Mark Weaver, P.E., S.E. (K&C) Leonardo Torres, P.E., S.E. (K&C) Garry D. Myers, P.E., S.E. (K&C)

B-15-91 pg 2 Project Objectives

Expand market opportunities for wood construction in Department of Defense and growing civilian markets requiring blast resistant structures.

Work with the Army Corps of Engineers Protective Design Center to develop an acceptable mass timber blast resistant alternative to steel and masonry.

Create a basis for inclusion of mass timber solution(s) in the Unified Facilities Criteria’s conventional construction provisions.

B-15-91 pg 3 Project Deliverables

Develop analytical methodologies to analyze CLT for blast loads. Both SDOF and high-fidelity physics-based (HFPB) FE methods will be developed.

Conduct static and dynamic CLT testing that tests / improves developed analytical methodologies.

Document analytical methodologies and test data in a form that could be used in blast analysis by structural engineers and potentially incorporated into SBEDS.

Establish a foundation for characterizing material dynamic response of Nail Laminated Timber walls.

B-15-91 pg 4

Conduct literature review.

Develop preliminary SDOF analysis methodology.

Define target conventional CLT construction.

Create HFPB FE CLT model.

Perform static CLT testing.

Refine SDOF and HFPB FE analysis methodologies.

Perform dynamic CLT testing.

Document literature review, analysis methodologies, and testing results in report form.

Publicize findings of effort.

Project Overview Approach & Organizational Chart

B-15-91 pg 5

Literature Review Overview

Sources Sought Published testing results that document out-of-plane response of

CLT. Case studies that document the usage of CLT in practice. CLT standards and design aids.

Conclusion Limited published test results that documents out-of-plane

response of laminated timber exposed to high-strain rates.

B-15-91 pg 6

Preliminary Scoping Analyses Single Degree-of-Freedom

Preliminary Assumptions Ultimate resistance, ru, and equivalent stiffness, k, derived

using “shear analogy” method (Kreuzinger, 1999). Both flexural and shear stiffness were used to derive equivalent

stiffness.

Residual resistance, rr, derived assuming innermost ply(s) provides flexural strength.

Assume immediate softening stiffness is equivalent to initial stiffness.

Static increase factor (from ANSI/APA PRG 320-2012) 2.1 for out-of-plane flexure. 3.15 for out-of-plane shear.

Dynamic increase factor set equal to one and CD = 1 Response limit: Ductility, µ = 1 (i.e., elastic response only).

All of the above assumptions will be investigated via the UMaine static testing and ideally refined based on uOttawa and PDC CLT testing.

k k

ru

rr

∆e ∆r

Outermost CLT ply ruptures

Innermost CLT ply ruptures

Schematic SDOF Flexural Resistance Function for 3-Ply CLT

B-15-91 pg 7

Preliminary Scoping Analyses Typical Grade Information

B-15-91 pg 8

Preliminary Scoping Analyses Supported Weight: Wood Panel (i.e., 10 psf)

EWII

EWI 32’

75’

43’

60’

81’ 104’

146’

200’

B-15-91 pg 9

Preliminary Scoping Analyses Supported Weight: Brick Veneer (i.e., 44 psf)

EWII

EWI

23’

28’

42’

53’

53’

67’

100’ 127’

B-15-91 pg 10

Preliminary Scoping Analyses Proposed Conventional Construction Options

Wall Type Sections Span

Min. Static

Material Strength

EWI Standoff Distance

EWII Standoff Distance

Reinforced Concrete ≥ 6” 12’ – 20’ 3,000 psi 66 16

CLT – Brick Veneer (44 psf) 5-ply 10’ – 14’ Grade E1 53 23

CLT – Brick Veneer (44 psf) 3-ply 10’ – 14’ Grade E1 67 28

Reinforced Masonry 8” – 12” 10’ – 14’ 1,500 psi 86 30

CLT – Wood Panel (10 psf) 5-ply 10’ – 14’ Grade E1 75 32

Wood Studs – Brick Veneer 2x4 & 2x6 8’ – 10’ 875 psi 105 36

CLT – Brick Veneer (44 psf) 5-ply 10’ – 14’ Grade V2 100 42

CLT – Wood Panel (10 psf) 3-ply 10’ – 14’ Grade E1 104 43

CLT – Brick Veneer (44 psf) 3-ply 10’ – 14’ Grade V2 127 53

CLT – Wood Panel (10 psf) 5-ply 10’ – 14’ Grade V2 146 60

Steel Studs – Brick Veneer 600S162-43; 600S162-54; 600S162-68 8’ – 12’ 50,000 psi 187 75

CLT – Wood Panel (10 psf) 3-ply 10’ – 14’ Grade V2 200 81

Wood Studs – EIFS 2x4 & 2x6 8’ – 10’ 875 psi 207 86

Steel Studs – EIFS 600S162-43; 600S162-54; 600S162-68 8’ – 12’ 50,000 psi 361 151

B-15-91 pg 11

Proposed Static CLT Testing Overview

Objective: Investigate out-of-plane behavior of CLT for different conventional connection configurations.

Tests will be used to develop resistance functions for SDOF analysis.

5 to 7 days of testing at University of Maine.

Proposed panel: 3-ply (and/or 5-ply), two different grades, 4’x8’ specimen size.

Two connection configurations to be tested (likely self-tapping screws & brackets).

Baseline (i.e., roller supports)

Brackets (weaker)

Brackets (stronger)

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Proposed Static CLT Testing Test Jig Concept

Panels w/o Connections water bladder

water bladder

Deflection gage

Panels w/ Connections

Reaction floor

Reaction floor

B-15-91 pg 13

Objective To demonstrate the blast resistance capability of cross-laminated timber (CLT) via a live blast

field full-scale test. To validate SDOF and HFPB FE analysis methodologies.

Peak Blast Load EWII at 30-ft

Test Configuration Options Option 1: One (or two) 1- to 2-story, 30’x15’ two bay CLT structures. Option 2: (24) 4’x10’ panels supported by previously constructed reaction structures. For

purposes of cost, assume 3 panels are tested at a time.

Proposed CLT Dynamic Testing Overview

Opening

CLT Partition

1st Shot

2nd Shot

OPTION 1 CONFIGURATION

B-15-91 pg 14 Live Blast Testing