PROFIS Design Guide - AC 318-19 July 2022

2.0 SHEAR

2.1 Concrete Breakout Failure Mode

Results V _ua

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

V _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 ACI 318-19 Table 17.5.2 showing provisions for shear calculations .

Table 17.5.2 — Design strength requirements of anchors

Failure Mode Single Anchor

Individual anchor in a Group

Steel strength in shear
( 17.7.1 )	ϕV _sa ≥ V _ua	ϕV _sa ≥ V _ua _, _i

Anchor Group

Anchors as a group

ACI 318-19 strength design provisions for concrete breakout failure in shear require calculation of a nominal concrete breakout strength ( V _cb or V _cbg

). The nominal strength is multiplied by a strength reduction factor ( ϕ-factor ) to obtain a design strength ( ϕV _cb or ϕV _cbg ). Design strength is checked against a factored shear load , defined by the parameter “ V _ua ”. Chapter 2 in ACI 318-19 gives the following definitions for the factored shear load parameter “ V _ua ”.

• V _ua

= factored shear force applied to a single anchor or group of anchors ( lb )

• V _ua _, _i

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

• V _ua _, _g

= total factored shear force applied to anchor group ( lb ) The design concrete breakout strength for a single anchor in shear ( ϕV _cb

) calculated per Section 17.7.2 is checked against the factored shear load acting on the anchor , which is designated “ V _ua

” in Table 17.5.2 . If ϕV _cb

≥ V _ua , the provisions for considering concrete breakout failure in shear have been satisfied per Table

17.5 . 2 .

Concrete breakout strength 11 shear ( 17.7.2 ) Concrete pryout strength in shear ( 17.7.3 )	ϕV _cb ≥ V _ua ϕV _cp ≥ V _ua	ϕV _cbg ≥ V _ua _, _g ϕV _cpg ≥ V _ua _, _g	The design concrete breakout strength for a group of anchors in shear ( ϕV _cbg ) calculated per Section 17.7.2 is checked against the total factored shear load acting on the anchors that are in shear , which is designated “ V _ua _, _g ” in Table 17.5.2 . If ϕV _cbg ≥ V _ua _, _g , the provisions for considering concrete breakout failure in shear have been satisfied per Table 17.5.2 . The PROFIS Engineering report uses the generic designation “ V _ua ” to define the factored shear load being checked against the calculated design concrete breakout strength ϕV _cb or ϕV _cbg . 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 shear loads . The software only performs shear load checks per Table 17.5.2 if shear loads have been input via one of the load input functionalities .
			If a single anchor in shear is being modeled , PROFIS Engineering calculates the parameter ϕV _cb , and checks this value against either ( a ) the factored shear load acting on the anchor , which has been calculated using the loads input via the Load Engine , ( b ) the factored shear load acting on the anchor , which has been calculated using the loads imported from a spreadsheet or ( c ) the factored shear load acting on the anchor , which has been calculated using the loads input in the matrix on the main screen . The value for V _ua shown in the report corresponds to the factored shear load determined to be acting on the anchor .
			If a group of anchors in shear is being modeled , PROFIS Engineering calculates the parameter ϕV _cbg , and checks this value against either ( a ) the total factored shear load acting on the anchor group , which has been calculated using the loads input via the Load Engine , ( b ) the total factored shear load acting on the anchor group , which has been calculated using the loads imported from a spreadsheet or ( c ) the total factored shear load acting on the anchor group , which has been calculated using the loads input in the matrix on the main screen . The value for V _ua shown in the report corresponds to the total factored shear load determined to be acting on the anchor group .
			Reference the Results section of the PROFIS Engineering report for more information on the following parameters : V _cb : nominal shear concrete breakout strength for a single anchor . V _cbg : nominal shear concrete breakout strength an anchor group . ϕ _concrete : strength reduction factor for concrete failure modes . ϕ _seismic : strength reduction factor for seismic loads . ϕ _nonductile : strength reduction factor for non-ductile failure modes .

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

PROFIS Design Guide - AC 318-19 July 2022 | Page 205

2.0 SHEAR