Anchorage to Concrete – Means and Methods

1ACI | 4/22/07 | jfs 1www.hilti.com

ACI SPRING CONVENTION ATLANTA, APRIL 2007 HOT TOPIC SESSION

Anchorage to Concrete Means and MethodsStructural Anchor Types and General Selection Criteria

J. Silva, SEDirector Codes & Standards

Hilti North America

ACI | 4/22/07 | jfs 2www.hilti.com


its all Greek to me



Manolis Korres, From Pentelicon to the Parthenon, Publishing House Melissa, 1995, p. 113



Manolis Korres, From Pentelicon to the Parthenon, Publishing House Melissa, 1995, p. 110

crack-prevention reinforcement



government anchors

F.E. Kidder, Building Construction and Superintendence, Part I, Wm Comstock, NY, 1909, p. 355



Golden Gate Bridge north anchorage - anchorage weight 60,000 tons



Anchor bolts

Cast in place Post-installed

all devices placed in the formwork prior to casting

all devices installed in hardened concrete



cast in place anchor bolts

J bolt L boltbolt with bearing plate



R. Park, T. Paulay, Reinforced Concrete Structures, Wiley-Interscience, 1975, p.411.



weld plate (embed)

tank wall

anchor ring

stiffener

tank anchorage



Coalinga earthquake of May 1983

Surge tank ABs: 1-1/2" A307 bolts stretched uniformly 1 to 1-1/2 inches

1 to 1-1/2"

H. J. Degenkolb



Anchor bolt specification:

DO: specify ASTM F1554

covers 36, 55 and 105-ksi in hooked, headed and threaded/nutted configurations

DO NOT: specify A325 or A490 or A36.



Anchor bolt specification:

DO: specify AISC base plate hole recommendations. These are larger than standard oversize holes. Use heavy plate washers.

1/05 Concrete International, Tolerance Compatibility Checklist, B. Suprenant

DO NOT: specify standard oversize holes

AISC 3rd Edition Table 14-2



1997 ASCE Wind Loads and Anchor Bolt Design for Petrochemical Facilities



Post-installed anchors



Basic Post-Installed Anchor Types

post-installed anchors

mechanical adhesive

undercut expansion

torque-controlled

displacement-controlled

capsule injection

hybridsscrews



self undercutting undercut anchor

drop-in displacement-controlled expansion anchor

undercut anchor

wedge-type torque-controlled expansion anchors heavy-duty sleeve type torque-controlled expansion anchor

Glossary displacement controlled anchors

drop-ins

expansion anchors

mechanical anchors

metal anchors

screw anchors

shell-type anchors

torque controlled anchors

undercut anchors

wedge anchorsscrew anchor

Hilti, Inc.

Post-installed mechanical anchors



Hilti, Inc.



Hilti, Inc.



Hilti, Inc.



Hilti, Inc.



Hilti, Inc.



cartridge injection anchor systems

capsule anchors

rail anchor

Glossary adhesive anchors

chemical anchors

bonded anchors

epoxy anchors

capsule anchors

cartridge injection anchors

bucket mixed

bulk dispensed

torque-controlled adhesive anchors

torque-controlled adhesive anchor

Post-installed adhesive (chemical) anchors



Hilti, Inc.



Hilti, Inc.





U.S. Custom House, San Francisco1906 Beaux Art structure

Center core 60 feet to foundationInstall anchors (Dywidag threadbar)Prestress against concrete bond beam

URS/Blume

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mechanical adhesive

undercut expansion

torque-controlled


capsule injection


hybridsscrews



drop-in anchorsHilti, Inc.

Simpson StrongTie





mechanical adhesive

undercut expansion

torque-controlled


capsule injection

torque-controlled

hybridsscrews

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wedge-type expansion anchors

Hilti (galvanized)

Simpson StrongTie

Powers

Hilti (316)



Torque-controlled expansion anchors heavy-duty, sleeve type

Hilti Sanko MKT Powers



torque-controlled expansion anchor (HSLG)Hilti, Inc.

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Basic Anchor Types


mechanical adhesive

undercut expansion

torque-controlled


capsule injectionundercut

hybridsscrews



undercut anchorsHeinrich LiebigStahlduebelwerke GmbH

Drillco National Group



Heinrich LiebigStahlduebelwerke GmbH

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self-undercutting undercut anchors

Hilti Inc. Heinrich LiebigStahlduebelwerke GmbH



undercut anchor (self-undercutting)Hilti, Inc.



Basic Anchor Types


mechanical adhesive

undercut expansion

torque-controlled


capsule injectioncapsule

hybridsscrews

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all-thread (HAS)

internally-threaded insert (HIS)

rebar

HVU capsule

capsule anchor system

Hilti, Inc.



Hilti, Inc.



Basic Anchor Types


mechanical adhesive

undercut expansion

torque-controlled


capsule injectioninjection

hybridsscrews

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cartridge adhesive anchor system

The HY adhesives are hybrid materials which combine a vinyl urethane methacrylate with a synthetic cement. They were developed to provide rapid bonding, low toxicity, and temperature resistance.

internally threaded insert

Hilti, Inc.



Injection system

Hilti, Inc.





mechanical adhesive

undercut expansion

torque-controlled


capsule injection

hybridsscrews

hybrids

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torque-controlled adhesive anchors

(hybrid anchors)



torque-controlled adhesive anchor

Suitable for use in cracked concrete. Superior performance in poorly cleaned holes.

Hilti, Inc.



1. de-bonding upon application of setting torque

2. displacement under load

3. generation of additional expansion force (re-expansion)

Basic working principle of the torque-controlled adhesive anchor

note: bond line thickness exaggerated for clarity Hilti, Inc.

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Hilti, Inc.



Application Guidance for Structural Post-Installed Anchors

load case light duty/non-structural structural connections gravity wedge anchors

adhesive anchors drop-ins

wedge anchors heavy-duty torque-controlled anchors adhesive anchors

shear only

seismic wedge anchors adhesive anchors

wedge anchors heavy-duty torque-controlled anchors undercut anchors large diameter/long adhesive anchors

gravity wedge anchors adhesive anchors

heavy-duty torque-controlled anchors undercut anchors

shear and/or tension

seismic wedge anchors adhesive anchors

heavy-duty torque-controlled anchors undercut anchors large diameter/long adhesive anchors

light duty/non-structural structural connections

gravity

seismic

gravity

seismic

shear only

shear and/or tension



anchorage to concrete

rebar development attachments to concrete

rebar dowels

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Hilti, Inc.



Hilti, Inc.



Hilti, Inc.

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Hilti, Inc.



Hilti, Inc.



Testing and assessment

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Document flow for anchor qualification and design in concrete

IBC Section 1913 Strength Design of Anchors

ACI 318 Appendix D Anchoring to Concrete

ACI 355.2 Qualification of Post-Installed Mechanical Anchors

AC193 Acceptance Criteria for Mechanical Anchors in Concrete Elements

AC308 Acceptance Criteria for Post-Installed Adhesive Anchors in Concrete Elements



1. Identification tests

2. Reference tests

3. Reliability tests

4. Service condition tests

ACI Standard 355.2-04 defines the testing requirements for post-installed mechanical anchors (expansion and undercut anchors)

It defines four types of tests:



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Hilti, Inc.



REFERENCE DISPLACEMENT

REFERENCE EXPANSION



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Report of ACI Committee 224, Control of Cracking in Concrete Structures



uncracked concrete

cracked concrete

The effect of cracking on anchor concrete breakout capacity is two-fold:

a. Effect on hoop stresses (all anchors)

b. Degradation of force-transfer mechanism (bonded anchors, expansion anchors...)crack plane

Eligehausen, Malle, Silva, Anchorage in Concrete Construction, Ernst & Sohn, 2006, p. 147.



Drop-in anchorsLoad-displacement curves for fully-and partially-expanded drop-inanchors in uncracked and crackedconcrete (crack width 0.4 mm)


w = 0.4 mm

fc = 21 N/mm2

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Torque-controlledexpansion anchorswith marginal followup expansionLoad-displacementcurves for M12 wedgeanchors (hef=60 mm) setin uncracked concreteand in 0.4 mm line cracks

Nn




Torque-controlled expansionanchors with robust followupexpansionLoad-displacement curves for M12 HSL anchors set in uncracked concrete and in 0.4 mm line cracks

30% reduction




CIP studsLoad-displacement curvesfor 12 mm headed studsset in uncracked concreteand in 0.3 mm line cracks

uncracked concrete cracked concrete w = 0.3 mm w 34 N/mm2

Headed studs dia. = 12 mmhef = 80 mm

Displacement (mm)

Load (kN)

25% reduction


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photo courtesy of R. Eligehausen

moving crack test University of Stuttgart

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Nw static

Crack width w cycled between 0.1+ mm and 0.3+ mm

Moving crack testTest 8, Table 4.2, ACI 355.2-04

Reinforcing bars

Spring pot

LVDT

Concrete

Hairline crack induced by bar tension



anch

or d

ispl

acem

ent (

mm

)

no. of cycles0 10 20 100 1000

1

2

3

4

5

successful test

unsuccessful test

crack movement test acceptance criteria

Nb,r



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Shear testing rig Hilti R&D

Hilti, Inc.



1.5 mm 0.75 mmdo 1.5 mm

shear loading plate geometry per ASTM E 488

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Hilti R&DHilti R&D

Hilti, Inc.



Hilti, Inc.



Connections between Steel and Concrete

Sept. 4 to 7, 2007Stuttgart, Germany

Objective:Forum for civil and structural engineers in research and practice to present and to discuss the state-of-the-art as well as new research developments in the field of fastening technology.

Early bird registration:May 31, 2007

iwb.uni-stuttgart.de/symposium

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John F. Silva, SE

Director, Codes & Standards

Hilti North America

Documents

Anchorage to Concrete – Means and Methods