22/05/2015 Proposed Australian design standard and installer certification for safety- critical anchors to concrete - David J Heath - Ramil Crisolo www.aefac.org.au 1 D ISCLAIMER These seminar notes have been prepared for general information only and are not an exhaustive statement of all relevant information on the topic. This guidance must not be regarded as a substitute for technical advice provided by a suitably qualified engineer. For further information contact David Heath: aefac@aefac.org.au 2 AEFAC 1
22/05/2015 O VERVIEW Part 1 � Australian Engineered Fasteners and Anchors Council � Safety-critical anchors � Design methodology � Case study � Proposed AEFAC Standard Part 2 � Post-installed fasteners � Performance considerations � AEFAC Installer Certification Program � Additional resources � Summary & acknowledgements 3 A USTRALIAN E NGINEERED F ASTENERS & A NCHORS C OUNCIL 4 AEFAC 2
22/05/2015 A USTRALIAN E NGINEERED F ASTENERS AND A NCHORS C OUNCIL � United approach + improved safety + minimum standards � Consistency in test methods and specification � Education to industry Formed in 2012 to stop anchor failures! 5 A USTRALIAN E NGINEERED F ASTENERS AND A NCHORS C OUNCIL Guidelines for the Training & accreditation specification of anchors for installers of anchors For Designers For Contractors Guideline for field testing Minimum performance & AEFAC standard specification & certification of anchors For Field Engineers For Manufacturers Research & Development For anchor industry 6 AEFAC 3
22/05/2015 A USTRALIAN E NGINEERED F ASTENERS AND A NCHORS C OUNCIL Founding Board Members Supporting Members 7 A USTRALIAN E NGINEERED F ASTENERS AND A NCHORS C OUNCIL Board of Founding Members Chair: Professor Emad Gad Ancon, Hilti, Hobson, ITW Construction Systems, Powers, Würth & Swinburne University of Technology National Technical Manager Training & Development Manager David Heath Jessey Lee Technical Committee Chair: Neil Hollingshead (ITW) Founding Members: Joe Rametta (Hilti), Ramil Crisolo (Hobson), Hany Genidy(Ancon), Tarun Joshi (Powers), Emad Gad (Swinburne), Kamiran Abdouka (Würth) Supporting Members: Brett King (Allthread Industries), Gilbert Balbuena (Simpson Strong-Tie) AEFAC: David Heath, Jessey Lee General Members (future) Other industry participants 8 AEFAC 4
22/05/2015 S AFETY -C RITICAL A NCHORS 9 S AFETY -C RITICAL A NCHORS 10 AEFAC 5
22/05/2015 S AFETY -C RITICAL A NCHORS Products � Significant growth in use of anchor products � New products entering the market Governance � Anchor industry largely relies on self-regulation � How can you design to best practice? � No Australian design or testing guidelines (except AS3850) Conformity assessment � Lack of conformity assessment culture in Australia � What does the product conform to? 11 S AFETY -C RITICAL A NCHORS � Safety-critical anchors - failure would risk human life and have potential for considerable economic consequences 12 AEFAC 6
22/05/2015 S AFETY -C RITICAL A NCHORS A “safe” anchoring system: Independent testing and assessment (via 1. P REQUALIFICATION ETA/ICC) to demonstrate “fit for purpose” Rigorous assessment to develop 2. D ESIGN solution for a given application Informed and competent installer 3. I NSTALLATION having appropriate supervision 13 S AFETY -C RITICAL A NCHORS European United States ETA prEN 1992-4 ICC ESR ACI 318 (prequalification) (design) (prequalification) (design) 14 AEFAC 7
22/05/2015 D ESIGN METHODOLOGY 15 D ESIGN M ETHODOLOGY AS3600 (2009) Cl. 14.3 (d) Fixings “The design strength of this anchorage shall be taken as ϕ times the ultimate strength, where ϕ = 0.6. In the case of shallow anchorages, cone-type failure in the concrete surrounding the fixing shall be investigated taking into account edge distance, spacing, the effect of reinforcement, if any, and concrete strength at time of loading.” 16 AEFAC 8
22/05/2015 D ESIGN M ETHODOLOGY Concrete Capacity Method � Developed in Europe � Published in ETAG 001 (1997) � ACI uses “CCD” (very similar) � Accurate prediction of the suitability of a specific anchor to a specific application � Only compatible with anchors that have been tested and assessed in accordance with strict guidelines 17 D ESIGN M ETHODOLOGY Tension failure modes ANCHOR CONCRETE BLOW-OUT PULL-OUT COMBINED SPLITTING FRACTURE CONE CONE & PULL-OUT SUPPLEMENTARY SUPPLEMENTARY REINFORCEMENT REINFORCEMENT – ANCHORAGE – FRACTURE CHANNEL ANCHOR CHANNEL ANCHOR/ FAILURE BOLT LIP FLEXURE CHANNEL FRACTURE CONNECTION 18 AEFAC 9
22/05/2015 D ESIGN M ETHODOLOGY Shear failure modes FRACTURE (NO BENDING PRYOUT (a) FRACTURE (b) ANCHORAGE EDGE SUPPLEMENTARY REO. LEVER ARM) (LEVER ARM) FAILURE FAILURE FRACTURE BENDING ANCHOR ANCHOR/ LIP EDGE PRYOUT (NO LEVER (LEVER FRACTURE CHANNEL FLEXURE FAILURE FAILURE ARM) ARM) CONNECT. SUPPLEMENTARY REO. 19 D ESIGN M ETHODOLOGY Example: Concrete cone failure mode (tension) A 0 c , N N N = ψ ψ ψ ψ Inverted rectilinear , , , , , , Rk c Rk c 0 s N re N ec N M N A c , N pyramid Cross-section 0 N characteristic concrete cone strength (no spacing effects, edge = Rk , c effects, etc. 1 . 5 k f ' c h = 9 ef A adjustment for effects of fastener spacing and edge effects (can the c , N = 0 full inverted rectilinear pyramid cone form?) A c , N factor accounting for disturbance of stresses in concrete due to an edge ψ = s , N ψ = factor accounting for a dense layer of reinforcement in concrete re , N Plan view ψ = factor accounting for different tension loads on fasteners in a group ec , N subjected to eccentric loading ψ = factor accounting for the influence of a compression force between the M , N fixture and concrete when a bending moment is present NB: Still need to consider other potential modes of failure to determine decisive failure mode! 20 AEFAC 10
22/05/2015 D ESIGN M ETHODOLOGY Software � Freely available from reputable manufacturers � Rapidly solve complex designs (minutes vs. hours/days!) � Include prequalified products (i.e. ETA) � Compatible with AEFAC Standard (with conversion) 21 D ESIGN M ETHODOLOGY But I’ve been doing it this way for years! 22 AEFAC 11
22/05/2015 C ASE STUDY 23 C ASE S TUDY � 11.20pm, August 13, 2011, 190 feet (58 m) canopy-fence collapsed onto the 20 lane Interstate Highway 75/85 Source: www.wsbtv.com 24 AEFAC 12
22/05/2015 C ASE S TUDY � Nobody was injured, no vehicles damaged � Canopy-fence collapsed onto 20-lane Interstate Highway 75/85 � Investigation found: � Bridge opened seven years earlier (2004) � Anchors were subjected to sustained load that was substantially lower than (approx. ¼ of) the design service load � Voids 1 – 1.5 inches in length detected at rear of holes � Wet epoxy extracted from holes (7 years after installation) � Laboratory studies revealed different material composition in different areas and hardener-rich and resin-rich areas � Adhesive was susceptible to creep 25 C ASE S TUDY Bent anchor rod, some that is smooth – without thread Eccentricity C T Epoxy removed from hole seven Typical column-cantilever assembly detail. years after installation . Source: 17 th Street Bridge Canopy Failure Investigation, Report No. 2011.3732.0, WJE Associates Inc. 26 AEFAC 13
22/05/2015 P ROPOSED AEFAC S TANDARD 27 P ROPOSED AEFAC S TANDARD Overview � Based on European guidelines (prEN 1992-4) � ‘Adaptation’ required: notation and terminology, referencing local standards, material properties, etc. � Fundamental design procedure unchanged � Compatible with products having ETAs � Proposed referencing in Building Code of Australia � Currently available for public comment ( www.aefac.org.au ) 28 AEFAC 14
22/05/2015 P ROPOSED AEFAC S TANDARD Scope � Post-installed fasteners � Mechanical anchors (expansion anchors, undercut anchors & concrete screws) � Chemical anchors (bonded anchors, bonded expansion anchors) � Cast-in fasteners � Headed fasteners � Anchor channel 29 P ROPOSED AEFAC S TANDARD Development Committee � Allthread Industries Pty Ltd � Hilti (Aust.) � Ancon Building Products � Housing Industry Association Ltd � Australian Building Codes Board � Hobson Engineering Company Pty � Australian Engineered Fasteners and Ltd � ITW Construction Systems Anchors Council � Australian Steel Institute � National Precast Concrete � Australian Window Association Association Australia � Commonwealth Scientific and � Simpson Strong-Tie � Stanley Black & Decker Australia Pty Industrial Research Organisation (CSIRO) Ltd (Powers) � Concrete Institute of Australia � Swinburne University of Technology � Edith Cowan University � Würth Australia Pty Ltd � Engineers Australia 30 AEFAC 15
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