PROFIS Design Guide - AC 318-19 July 2022

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1.4 Side Face Blowout Failure Mode

Results N _ua

Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering

N _ua

17.5 . 2 For each applicable factored load combination , design strength of anchors shall satisfy the criteria in Table 17.5.2 .

Excerpt from Table 17.5.2 showing the tension failure modes considered in ACI 318-19 anchoringto-concrete provisions .

Table 17.5.2 — Design strength requirements of anchors

Failure Mode Single Anchor

Individual anchor in a Group

Steel strength in tension ( 17.6.1 ) ϕN _sa ≥ N _ua ϕN _sa

≥ N _ua _, _i

Concrete breakout strength in tension ( 17.6 . 2 ) ϕN _cb

≥ N _ua

Pullout strength in tension ( 17.6.3 ) ϕN _pn ≥ N _ua ϕN _pn

≥ N _ua _, _i

Anchor Group

Anchors as a group

ϕN _cbg

≥ N _ua _, _g

ACI 318-19 strength design provisions for side-face blowout failure in tension require calculation of a nominal side-face blowout strength ( N _sb or N _sbg

). The nominal strength is multiplied by one or more strength reduction factors ( ϕ-factors ) to obtain a design strength ( ϕN _sb or ϕN _sbg

). ϕ-factors are relevant to static and seismic load conditions .

Design strength is checked against a factored tension load , defined by the parameter “ N _ua

”. Chapter 2 in ACI 318-19 gives the following definitions for the factored tension load parameter “ N _ua

”.

• N _ua

= factored tensile force applied to anchor or individual anchor in a group of anchors ( lb )

• N _ua _, _i

= factored tensile force applied to most highly stressed anchor in a group of anchors ( lb )

• N _ua _, _g

= total factored tensile force applied to anchor , group ( lb )

Concrete side-face blowout strength in tension ( 17.6.4 ) Bond strength of adhesive anchor in tension ( 17.6.5 )	ϕN _sb ≥ N _ua ϕN _a ≥ N _ua	ϕN _sbg ≥ N _ua _, _g ϕN _ag ≥ N _ua _, _g	The design side-face blowout strength for a single anchor in tension ( ϕN _sb ) calculated per Section 17.6.4 is checked against the factored tension load acting on the anchor , which is designated “ N _ua ” in Table 17.5.2 . If ϕN _sb ≥ N _ua , the provisions for considering side-face blowout failure in tension have been satisfied per Table 17.5.2 .
			The PROFIS Engineering Load Engine permits users to input service loads that will then be factored per IBC factored load equations . Users can also import factored load combinations via a spreadsheet , or input factored load combinations directly on the main screen . PROFIS Engineering users are responsible for inputting tension loads . The software only performs tension load checks per Table 17.5.2 if tension loads have been input via one of the load input functionalities .
			If a single anchor in tension is being modeled , PROFIS Engineering calculates the parameter ϕN _sb , and checks this value against either ( a ) the factored tension load acting on the anchor , which has been calculated using the loads input via the Load Engine , ( b ) the factored tension load acting on the anchor , which has been calculated using the loads imported from a spreadsheet or ( c ) the factored tension load acting on the anchor , which has been calculated using the loads input in the matrix on the main screen . The value for N _ua shown in the report corresponds to the factored tension load determined to be acting on the anchor .
			Reference the Equations section of the PROFIS Engineering report for more information on the parameter ϕN _sb .

134 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions

PROFIS Design Guide - AC 318-19 July 2022 | Page 134

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