Example calculation for a group of (2) Titen HD® anchors using ASD:

Design a connection comprised of two (2) 3/4" diameter Titen HD® anchors installed in the face of an 8" normal weight grouted CMU wall as shown. The anchor group has an applied tension load of 600 lbs. and an applied shear load of 500 lbs. acting simultaneously.

Two Anchor Layout.

The allowable tension (or shear) value for a group of anchors is equal to the lowest (minimum) tension (or shear) value for a single anchor within the group multiplied by the number of anchors within the group.

• Embedment depth = 5 1/2"
• Spacing = S_act = S1 = 8".
• Critical spacing for 3/4" dia. anchor at embedment = S_cr = 12".
• S_act< S_cr therefore use spacing reduction factor for S1.
• End distance = C_act = C1 = 4"
  Edge distance = C_act = C2 = 12"
• Critical edge distance = C_cr = 12".
• Critical end distance = C_cr = 12".
• C1 < C_cr , therefore use perpendicular-to-edge reduction factor for C1.
• C2 > C_cr , therefore no edge reduction factor for C2.

TENSION:

Determine uninfluenced allowable tension load in the face of an 8" normal wt. concrete grouted CMU wall:

Uninfluenced allowable tension = 1,600 lbs.

Calculate reduced efficiency factors for Edge Distance:

C_act = C1 = 4"

C_act = C2 = 12"

f_cC1 = 0.66 = Load adjustment factor

Calculate reduced efficiency factor for spacing:

S_act = S1 = 8"

f_sS1 = 0.67 = Load adjustment factor

Calculate allowable tension load per anchor:

Allowable Tension = (uninfluenced allowable tension) (f_cC1)(f_sS1)

Allowable Tension = (1,600 lbs.)(0.66)(0.67)
                                   = 708 lbs. per anchor

For a group of 2 anchors the combined allowable tension value is:

= (2 anchors)(708 lbs./anchor) = 1,416 lbs. > 600 lbs.
(design tension) O.K.

SHEAR:

Determine uninfluenced allowable shear load in the face of an 8" normal wt. concrete grouted CMU wall

Uninfluenced allowable shear = 3,000 lbs.

Calculate reduced efficiency factor for end distance:

C_act = C1 = 4"

C_act = C2 = 12"

f_cC1 = 0.21 = Load adjustment factor

Calculate reduced efficiency factor for spacing:

S_act = S1 = 8"

f_sS1 = 0.75 = Load adjustment factor

Calculate Allowable Shear load per anchor:

Allowable Shear = (Uninfluenced Allowable Shear) (f_cC1)(f_sS1)

Allowable Shear = (3,000 lbs.)(0.21)(0.75) = 473 lbs. per anchor

For a group of 2 anchors the combined allowable shear value is:

= (2 anchors)(473 lbs./anchor) = 945 lbs. > 500 lbs.
(design shear) O.K.

CHECK COMBINED TENSION AND SHEAR INTERACTION:

For the Titen HD® in grouted CMU, use the straight-line method (n = 1, see Figure 1) when calculating the interaction of both tension and shear upon the anchor per the following equation:

(Design shear/Allowable shear)ⁿ + (Design tension/Allowable tension)ⁿ≤ 1.0, n=1

Design shear (V) = 500 lbs.

Allowable shear (V_all) = 945 lbs.

Design tension (T) = 600 lbs.

Allowable tension (V_all) = 1,416 lbs.

(600/1,416)¹ + (500/945)¹ = 0.95 ≤ 1.0     O.K.

Figure 1

Note: The elliptical method permits greater allowable tension and shear loads to be used than the straight-line method.