|
ESR-3699 Page 14 of 18
<br />
<br />
<br />TABLE 4—EXAMPLE ALLOWABLE STRESS DESIGN TNSION VALUES FOR ILLUSTRATIVE PURPOSES
<br />FOR TAPCON+ SCREW ANCHORS AND SAMMYS THREADED ROD ANCHORS 1,2,3,4,5,6,7,8,9
<br />NOMINAL ANCHOR
<br />DIAMETER
<br />(inch)
<br />NOMINAL EMBEDMENT DEPTH
<br />(inches)
<br />EFFECTIVE EMBEDMENT DEPTH
<br />(inches)
<br />ALLOWABLE TENSION LOAD
<br />(pounds)
<br />
<br />1/4 SAMMYS 2.25 1.4510 800
<br />1/4 2.00 1.45 920
<br />3/8 2.50 1.78 1,335
<br />1/2
<br />2.00 1.32 800
<br />3.00 2.17 1,685
<br />4.00 3.02 2,765
<br />For SI: 1 inch = 25.4 mm, 1 lbf = 4.45 N, 1 psi = 0.006895 MPa.
<br />1Single anchor with static tension load only.
<br />2Concrete determined to remain uncracked for the life of the anchorage.
<br />3Load combination from ACI 318 (-19 and -14) Section 5.3 or ACI 318-11 Section 9.2, as applicable, (no seismic loading).
<br />430 percent dead load and 70 percent live load, controlling load combination 1.2D + 1.6L.
<br />5Calculation of weighted average for = 0.3* 1.2 + 0.7* 1.6 = 1.48.
<br />6Normalweight concrete, f'c = 2,500 psi
<br />7ca1 = ca2 > cac.
<br />8h hmin.
<br />9Condition B where supplementary reinforcement in accordance with ACI 318 -19 17.5.3, ACI 318-14 Section 17.3.4 or ACI 318-11 Section
<br />D.4.4, as applicable, is not provided.
<br />10For calculation only. For actual hef see Table 1.
<br />
<br />Illustrative Procedure to Calculate Allowable Stress Design Tension Value:
<br />Tapcon+ Screw Anchor 1/2-inch diameter, using an embedment of 4-inches, assuming the conditions given in Table 4.
<br />
<br /> PROCEDURE CALCULATION
<br />Step 1 Calculate steel strength of a single anchor in tension Nsa = Nsa
<br />
<br />per ACI 318-19 17.6.1.2, ACI 318-14 17.4.1.2, ACI 318-11 D 5.1.2,
<br />Table 2 of this report: =0.70*23,125
<br /> =15,031 lbs steel strength
<br />
<br />Step 2
<br />Calculate concrete breakout strength of a single anchor in
<br />
<br />
<br />Nb
<br />
<br />
<br />= kuncr cf` hef1.5
<br />
<br />tension per ACI 318-19 17.6.2.2, ACI 318-14 17.4.2.2, ACI 318-11 D
<br />5.2.2, Table 2 of this report: = 24*500,2 *3.021.5
<br />
<br />
<br />
<br />
<br />Ncb
<br />
<br />
<br />
<br />= 6,298 lbs
<br />
<br />= ANC/ANC0 ψed,N ψc,N ψcp,N Nb
<br />= 0.65*1.0*1.0*1.0*1.0*6,298
<br />= 0.65*6,298
<br />= 4,093 lbs concrete breakout
<br />strength
<br />Step 3
<br />
<br />Calculate pullout strength per Table 2 of this report:
<br />
<br />Npn
<br />
<br />= Np,uncr ψc,P
<br />n/a – pullout strength does not
<br />control (see Table 2, footnote 4)
<br />
<br />
<br />
<br />Determine controlling resistance strength in tension
<br />Step 4
<br /> per ACI 318-19 17.5.2, ACI 318-14 17.3.1.1, ACI 318-11 D 4.1.1: = 4,093 lbs controlling resistance
<br />(concrete)
<br />
<br />Step 5
<br /> Calculate allowable stress design conversion factor for loading
<br />condition per ACI 318-19 and ACI 318-14 Section 5.3, or ACI 318-11
<br />Section 9.2:
<br />α
<br />
<br />=1.2D + 1.6L
<br />=1.2(0.3) + 1.6(0.7)
<br />=1.48
<br />
<br />Step 6
<br />
<br /> Calculate allowable stress design value per Tallowable,ASD = Nn / α
<br /> Section 4.2 of this report: = 4,093/ 1.48
<br /> = 2,765 lbs allowable stress
<br />design
<br />
<br />FIGURE 5—EXAMPLE DESIGN CALCULATION
<br />
|