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ESR-3699 Page 3 of 18
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<br />4.1.2 Requirements for Static Steel Strength in Tension, Nsa: The nominal static steel strength of a single
<br />anchor in tension is calculated in accordance with ACI 318-19 17.6.1.2, ACI 318-14 17.4.1.2 or ACI 318-11
<br />D.5.1.2, as applicable. The Nsa values of a single anchor are given in Table 2 of this report. Strength reduction
<br />factors, ïĶ, corresponding to brittle steel elements as defined in ACI 318 (-19 or -14) 2.3 or ACI 318-11 D.1, as
<br />applicable, and provided in Table 2, must be used.
<br />4.1.3 Requirements for Static Concrete Breakout Strength in Tension, Ncb or Ncbg: The nominal static
<br />concrete breakout strength for a single anchor or group of anchors in tension, Ncb or Ncbg, must be calculated in
<br />accordance with ACI 318-19 17.6.2, ACI 318-14 17.4.2 or ACI 318-11 D.5.2, as applicable, with modifications as
<br />described in this section. The basic concrete breakout strength in tension, Nb, must be calculated in accordance
<br />with ACI 318-19 17.6.2.2, ACI 318-14 17.4.2.2 or ACI 318-11 D.5.2.2, as applicable, using the values of hef and
<br />kcr as given in Table 2. The nominal concrete breakout strength in tension in regions of concrete where analysis
<br />indicates no cracking at service loads in accordance with ACI 318-19 17.6.2.5, ACI 318-14 17.4.2.6 or ACI 318-
<br />11 D.5.2.6, as applicable, must be calculated using the values of kuncr as given in Table 2 of this report with Ïc,N
<br />= 1.0.
<br />For 1/2-inch-diameter (12.7 mm) Tapcon+ Screw Anchors installed in the soffit of sand-lightweight or
<br />normalweight concrete on steel deck floor and roof assemblies, as shown in Figure 6, calculation of the concrete
<br />breakout strength is not required.
<br />4.1.4 Requirements for Static Pullout Strength in Tension, Np: The nominal pullout strength of a single
<br />anchor in tension in accordance with ACI 318-19 17.6.3.1 and 17.6.3.2.1, ACI 318-14 17.4.3.1 and 17.4.3.2 or
<br />ACI 318-11 D.5.3.1 and D.5.3.2, as applicable, in cracked and uncracked concrete, Np,cr and Np,uncr,
<br />respectively, is given in Table 2 of this report. For all design cases ðđð,ð=1.0. In accordance with ACI 318-19
<br />17.6.3, ACI 318-14 17.4.3 or ACI 318-11 D.5.3, as applicable, the nominal pullout strength in cracked concrete
<br />may be adjusted for concrete strengths according to Eq-1:
<br />ðð,ððâē=ðð,ðð(ððâē
<br />2,500)
<br />ð (lb,psi) (Eq-1)
<br />ðð,ððâē=ðð,ðð(ððâē
<br />17.2)
<br />ð (N, MPa)
<br />where fâēc is the specified compressive strength and n is the factor defining the influence of concrete strength
<br />on the pullout strength. For the 3/8-inch-diameter anchor in cracked concrete, n is 0.12. For all other diameters,
<br />n is 0.5.
<br />In regions where analysis indicates no cracking in accordance with ACI 318-19 17.6.3.3, ACI 318-14 17.4.3.6
<br />or ACI 318-11 D.5.3.6, as applicable, the nominal pullout strength in tension may be adjusted for concrete
<br />strengths according to Eq-2:
<br />ðð,ððâē=ðð,ðĒððð(ððâē
<br />2,500)
<br />ð (lb,psi) (Eq-2)
<br /> ðð,ððâē=ðð,ðĒððð(ððâē
<br />17.2)
<br />ð (N, MPa)
<br />where fâēc is the specified compressive strength and n is the factor defining the influence of concrete strength
<br />on the pullout strength. For all diameters, n is 0.5.
<br />Where values for Np,cr or Np,uncr are not provided in Table 2, the pullout strength in tension need not be
<br />evaluated.
<br />The nominal pullout strength in cracked concrete of the 1/2-inch-diameter (12.7 mm) Tapcon+ Screw Anchor
<br />installed in the soffit of sand-lightweight or normalweight concrete on steel deck floor and roof assemblies, as
<br />shown in Figure 6, is given in Table 5. In accordance with ACI 318-19 17.6.3.2.1, ACI 318-14 17.4.3.2 or ACI
<br />318-11 D.5.3.2, as applicable, the nominal pullout strength in cracked concrete must be calculated in
<br />accordance with Eq-1, whereby the value of Np,deck,cr must be substituted for Np,cr and the value of 3,000 psi
<br />(20.7 MPa) must be substituted for the value of 2,500 psi (17.2 MPa) in the denominator. In regions where
<br />analysis indicates no cracking in accordance with ACI 318-19 17.6.3.3, ACI 318-17.4.3.6 or ACI 318-11
<br />D.5.3.6, as applicable, the nominal strength in uncracked concrete must be calculated according to Eq-2,
<br />whereby the value of Np,deck,uncr must be substituted for Np,uncr and the value of 3,000 psi (20.7 MPa) must be
<br />substituted for the value of 2,500 psi (17.2 MPa) in the denominator.
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