WWW.CONCRETE.ORG/ACI318 1 Changes to the Concrete Design Standard ACI 318-19 WWW.CONCRETE.ORG/ACI318 2 American Concrete Institute is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this online course will be reported to AIA/CES for AIA members. registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. The American Institute of Architects has approved this course for 1 AIA/CES LU Learning Unit. International Code Council (ICC) The American Institute of Architects has approved this course for 1 AIA/CES LU learning unit. ACI is an AIA/CES registered provider. 2 WWW.CONCRETE.ORG/ACI318 3 Learning Objectives • Understand where higher grades of reinforcement are accepted and changes to the requirements for structural concrete to allow the higher reinforcement grades. • Identify changes to development lengths for straight bars, hooks, and headed deformed bars • Learn the new requirements for post-installed screw type anchors and shear lug design for anchoring to concrete. • Describe the changes to shear design provisions and equations. 1 2 3
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WWW.CONCRETE.ORG/ACI318 1
Changes to the Concrete Design Standard
ACI 318-19
WWW.CONCRETE.ORG/ACI318 2
American Concrete Institute is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this online course will be reported to AIA/CES for AIA members.
registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.
The American Institute of Architects has approved this course for 1 AIA/CES LU Learning Unit.
International Code Council (ICC)
The American Institute of Architects has approved this course for 1 AIA/CES LU learning unit.ACI is an AIA/CES registered provider.
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Learning Objectives• Understand where higher grades of
reinforcement are accepted and changes to the requirements for structural concrete to allow the higher reinforcement grades.
• Identify changes to development lengths for straight bars, hooks, and headed deformed bars
• Learn the new requirements for post-installed screw type anchors and shear lug design for anchoring to concrete.
• Describe the changes to shear design provisions and equations.
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ACI is
• A technical and educational society dedicated to improving design
construction
maintenance
repair
• One of the world’s largest sources of concrete knowledge
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ACI is NOT
• A Trade or Promotional Association
• A Government Agency
• An Educational Institution
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ACI Membership
ACI Members have immediate, digital access to ACI’s 200+ guides and reports. Members are engaged, informed, and stay up-to-date by taking advantage of
this and many other benefits ACI membership provides.
Laboratory Technicians | Insurance Agents | Everyone interested in concrete
www.concrete.org/membership
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• Codes
• Specifications
• Reports and Guides (Practices)
• Symposium Publications
• Manuals
• Annual ACI Collection (formerly MCP)
More than 400 technical documents, including:
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ACI Certification
From finishers and technicians, to supervisors, inspectors, and more, the American Concrete
Institute provides 20,000+ certifications annually in over 20 programs across the globe.
That’s over 400,000 individuals certified since the programs were launched back in the 1980s.
www.WhyACICertification.org
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Educational offerings
More than 175 online learning modules supporting:More than 175 online learning modules supporting:
• Technical committee documents
• Certification
• Monthly webinars
• Subscription option
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Changes to the Concrete Design Standard
ACI 318-19
Anchorage to Concrete
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New Content/Design Information
• Post-installed screw anchors– pre-qualification per ACI 355.2
• Attachments with shear lugs
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Screw Anchors (17.3.4)
• For screw anchors satisfying:– hef ≥ 1.5 in. and– 5da ≤ hef ≤ 10da
• Manufacturer provides hef, Aef, and pullout strength
• Concrete breakout evaluated similar to other anchors– 17.6.2 in tension – 17.7.2 in shear
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Minimum Spacing (17.9.2a)
• Screw anchor spacing limited per Table 17.9.2a
Spacing > 0.6hefand 6da
Greatest of: (a) Cover (b) 2 x max. agg.(c) 6da or per ACI 355.2
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Shear Lugs (17.11.1)
Shear lugs are fabricated from:• Rectangular plates
or • Steel shapes
composed of plate-like elements, welded to an attachment base plate
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Shear Lugs (17.11.1)
• Minimum four anchors
• Anchors do not need to resist shear forces if not welded
• Anchors welded to steel plate carry portion of total shear load
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Shear Lug Detailing (17.11.1.1.8)
• Anchors in tension, satisfy both (a) and (b): (a) hef/hsl ≥ 2.5 (b) hef/csl ≥ 2.5
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Shear Lug Detailing (17.11.1.2)
• Steel plate to have 1 in. dia. (min.) hole• Single plate – one on each side• Cross / cruciform plate - one each quadrant• More vent holes are not detrimental
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Shear Lug Overturning (17.11.1.1.9)
hef
hsl
tsl
Csl
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Bearing (17.11.2)
• f Vbrg,sl ≥ Vu
• Where f = 0.65
Source: Peter Carrato
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Bearing Strength (17.11.2)
• Bearing strength:
• Aef,sl is the surface perpendicular to the applied shear:
2tsl2tsl2tsl
', , ,1.7brg sl c ef sl brg slV f A
tsl
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Bearing AreaDirection of shear load
Direction of shear load
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17.11.2.2 – Bearing factor
Tension load• Ψbrg,sl = 1 + Pu/(nNsa) ≤ 1.0• Pu – negative for tension• n – number of anchors in tension• Nsa – Nominal tension strength of a single anchor
No applied axial load: Ψbrg,st = 1
Compression load: Ψbrg,sl = 1 + 4Pu/(Abpfc’) ≤ 2.0• Pu – positive for compression
', ,, 1.7 brg slbrg sl c ef slV f A
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Changes to the Concrete Design Standard
ACI 318-19
High-Strength Reinforcement
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Ch. 3 – Update of ASTM A615-18e1
• Latest ASTM A615 allows:– Gr. 100– Bars up to No. 20
• ACI 318-19 allows– No. 18 and smaller– Gr. 80 & 100 with
restrictions
• No. 20 not acceptable:– Development length– Bar bends
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Table 20.2.2.4(a)
• Main changes– Gr. 80– Gr. 100– Footnotes– Clarifications
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Ch. 20 – Steel Reinforcement Properties
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Ch. 20 –Seismic Requirements for A615 Gr. 60
• Section 20.2.2.5 specifies – ASTM A706 Gr. 60 allowed– Requirements for ASTM A615, Gr. 60