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Slip Resisting Bolted Connections. Source: Remi M. www.flickr.com/photos/remi_m. By: Joel Kerkhoff. Outline. Introduction Uses History & Code dev. Basic Theory Code requirements Spreadsheet Research Testing @ UBC Conclusion Questions.
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Slip Resisting Bolted Connections Source: Remi M. www.flickr.com/photos/remi_m By: Joel Kerkhoff Slip Resisting Bolted Connections - Joel Kerkhoff
Outline • Introduction • Uses • History & Code dev. • Basic Theory • Code requirements • Spreadsheet • Research • Testing @ UBC • Conclusion • Questions Port Mann Bridge deck connection (Remi M. – Flikr) Slip Resisting Bolted Connections - Joel Kerkhoff
Introduction What is a slip-resisting connection? • Two components • Tensioned bolts • Steel faying surfaces • A simple friction connection source: unknown Slip Resisting Bolted Connections - Joel Kerkhoff
Where is it used? Locations: • Stress reversal / fatigue • Vibration • Oversize/slotted holes • Bolts & welds share load • Where joint slippage is detrimental Slip Resisting Bolted Connections - Joel Kerkhoff
Where is it used? - examples Slot-bolted connection Source: www.eng.nus.edu.sg/EResnews/9711/nov97p1.html Karuah Bridge, South Wales, Australia (source www.rta.nsw.gov.au Roads and Traffic Authority, NSW) Slip Resisting Bolted Connections - Joel Kerkhoff
Where is it used? - examples Source: www.pbase.com/geoff_c Falkirk Wheel, Scotland Source: www.lucs.org.uk/falkirk_wheel.htm Slip Resisting Bolted Connections - Joel Kerkhoff
History and code development Historical • Rivets • Batho & Bateman – 1934 • RCRBSJ (now RCSC) – 1947 • ASTM – 1949 American codes/guides: • RCSC – www.boltcouncil.org • Specification for Structural Joints Using ASTM A325 or A490 Bolts • AISC • Guide to Design Criteria for Bolted and Riveted Joints (Kulak, Fisher, Struik) Slip Resisting Bolted Connections - Joel Kerkhoff
Basic Theory • Bolts provide the Normal Force (N) • m depends on faying surfaces Ff = mN Vr = ks * [bolt tension] Complexities in both factors. Source:en.wikipedia.org/wiki/Friction Slip Resisting Bolted Connections - Joel Kerkhoff
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 connection for Ultimate Limit States! Slip Resisting Bolted Connections - Joel Kerkhoff
Canadian Code Design CAN/CSA-S16.1-01 Table 3 Slip Resisting Bolted Connections - Joel Kerkhoff
Excel Spreadsheet • Compute slip resistance • Compute bolts for given shear • Simplify user input • Check for errors • Eliminate need to use ‘Blue Book’ source: Microsoft Slip Resisting Bolted Connections - Joel Kerkhoff
Research • Ongoing • International Prof. J. Hajjar - University of Illinois Source: www.nsel.cee.illinois.edu Blast cleaned steel test sample & 50kip clamping force Source: www.nsel.cee.illinois.edu 600 kip MTS Uniaxial testing Machine Slip Resisting Bolted Connections - Joel Kerkhoff
Testing at UBC • 12 samples • As Is / Mill scale • Blast-cleaned • 3 Samples left… Steel test sample • 100 Ton Baldwin testing machine Image sources: Jalayer, Stiemer and Youn. “Experimental Investigations of Slip Resistant Connections for Weathering Steel” Slip Resisting Bolted Connections - Joel Kerkhoff
Testing at UBC - results • Table: Slip Test Results Data source: Jalayer, Stiemer and Youn. “Experimental Investigations of Slip Resistant Connections for Weathering Steel” Slip Resisting Bolted Connections - Joel Kerkhoff
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 Slip Resisting Bolted Connections - Joel Kerkhoff
Questions Source: www.ezdiyelectricity.com/?p=526 Slip Resisting Bolted Connections - Joel Kerkhoff