Download - Slip Critical Presentation - Joel Kerkhoff
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3/26/2009 Slip Resisting Bolted Connections - Joel Kerkhoff
Slip Resisting Bolted
Connections
By: Joel Kerkhoff
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Source: Remi M. www.flickr.com/photos/remi_m
http://www.flickr.com/photos/remi_mhttp://www.flickr.com/photos/remi_m -
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Outline
Introduction
Uses
History & Code dev.
Basic Theory
Code requirements
Spreadsheet
Research
Testing @ UBC Conclusion
Questions
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Port Mann Bridge deck connection
(Remi M. Flikr)
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Introduction
What is a slip-resisting connection?
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Two components
Tensioned bolts
Steel faying surfaces
A simple friction connection
source: unknown
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Where is it used?
Locations:
Stress reversal / fatigue
Vibration
Oversize/slotted holes
Bolts & welds share load
Where joint slippage is detrimental
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Where is it used? - examples
Slot-bolted connection
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Karuah Bridge,
South Wales, Australia
(source www.rta.nsw.gov.au Roadsand Traffic Authority, NSW)
Source: www.eng.nus.edu.sg/EResnews/9711/nov97p1.html
http://www.rta.nsw.gov.au/http://www.eng.nus.edu.sg/EResnews/9711/nov97p1.htmlhttp://www.eng.nus.edu.sg/EResnews/9711/nov97p1.htmlhttp://www.rta.nsw.gov.au/ -
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Where is it used? - examples
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Falkirk Wheel, ScotlandSource: www.lucs.org.uk/falkirk_wheel.htm
Source: www.pbase.com/geoff_c
http://www.lucs.org.uk/falkirk_wheel.htmhttp://www.pbase.com/geoff_chttp://www.pbase.com/geoff_chttp://www.lucs.org.uk/falkirk_wheel.htm -
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History and code development
Historical
Rivets
Batho & Bateman 1934
RCRBSJ (now RCSC) 1947
ASTM 1949
American codes/guides:
RCSCwww.boltcouncil.org
Specification for Structural Joints Using
ASTM A325 or A490 Bolts AISC
Guide to Design Criteria for Bolted andRiveted Joints (Kulak, Fisher, Struik)
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http://www.boltcouncil.org/http://www.boltcouncil.org/ -
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Basic Theory
Bolts provide the Normal Force (N)
m depends on faying surfaces
Ff = mN Vr = ks * [bolt tension]
Complexities in both factors.
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Source:en.wikipedia.org/wiki/Friction
http://www.wikipedia.org/wiki/Frictionhttp://www.wikipedia.org/wiki/Friction -
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Canadian Code Design
CAN/CSA-S16.1-01 cl. 13.12.2
Vs = 0.53*c1*ks*m*n*Ab*Fu
Fu = specified minimum tensile strength
Ab = bolt cross sectional area
n = number of bolts
m = number of shear planes
ks = mean slip coefficient
c1 = 5th percentile coefficient
Slip resistance is a Service Limit State
Must design as regular bolt connectionfor Ultimate Limit States!
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Canadian Code Design
CAN/CSA-S16.1-01 Table 3
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Contact Surface of bolted Parts Friction c1
Class Description ks A325 bolt
AClean Mill Scale, or blast-cleaned withClass A coatings 0.33 0.82
BBlast-cleaned, or blast-cleaned withClass B coatings 0.5 0.89
C
Hot-dip galvanized with wire brushed
surfaces 0.4 0.9
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Excel Spreadsheet
Compute slip resistance
Compute bolts for given shear
Simplify user input Check for errors
Eliminate need to use Blue Book
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source: Microsoft
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Research
Prof. J. Hajjar - University of Illinois
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600 kip MTS Uniaxial testing Machine
Blast cleaned steel test sample
& 50kip clamping force
Ongoing
International
Source: www.nsel.cee.illinois.edu
Source: www.nsel.cee.illinois.edu
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Testing at UBC
Steel test sample
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100 Ton Baldwin testing machine
12 samples
o As Is / Mill scaleo Blast-cleaned
3 Samples left
Image sources: Jalayer, Stiemer and Youn. Experimental Investigationsof Slip Resistant Connections for Weathering Steel
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Testing at UBC - results
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Table: Slip Test Results
Surface Type Specimen Type Mean Slip
Load [kips]
Standard Dev
[kips]
COV
As Is Plate-to-flange 63.0 9.0 0.14
As Is Plate-to-plate 68.1 5.1 0.07
As Is All specimens 65.0 7.9 0.12
Blast-cleaned Plate-to-flange 62.6 2.4 0.04
Surface
Type
Specimen
Type
5th Percentile Coefficient
of Friction [ ]
Estimated
ks [ ]
S16.01
ks
As Is Plate-to-flange 0.35 0.42 0.33
As Is Plate-to-plate 0.43 0.520.33
As Is All specimens 0.37 0.45 0.33
Blast-
cleaned
Plate-to-flange 0.42 0.46 0.50
Data source: Jalayer, Stiemer and Youn. Experimental Investigations of SlipResistant Connections for Weathering Steel
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Concluding comments
Summary
Simple
Complicated
Acknowledgements & Resources
Professor Stiemer & Professor Youn
G.L Kulak Various publications
University of Illinois NSEL website test pictures
Google for finding some of the pictures
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Questions
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Source: www.ezdiyelectricity.com/?p=526
http://www.ezdiyelectricity.com/?p=526http://www.ezdiyelectricity.com/?p=526