Design Considerations

Williams has listed recommended embedment depths that are minimum values for ductile steel failure design in 3000 psi and 6500 psi concrete; respectively, in accordance with ACI 318 on page 28. Embedment depths will need to increase according to the values determined from anchor design models when spacing requirements are less than the values listed below (S). A reduction in anchor capacity should be used if the concrete thickness does not allow for deep-er embedments, as concrete breakout strength would control the design. When placing anchors that require a smaller edge distance (E) than what is recommended in the table below, the designer should be aware of a reduction in anchor capacity, as side face blowout strength would control the design.

S-7 Reusable Anchor – Minimum Spacing & Edge Distance

Outer Stud
Diameter
Center to Center Spacing
for Full Strength
with no reduction (S)
(3000 PSI Concrete)
Center to Center Spacing
for Full Strength
with no reduction (S)
(6500 PSI Concrete)
Minimum Recommended
Edge Distance (E)
(3000 PSI Concrete)
Minimum Recommended
Edge Distance (E)
(6500 PSI Concrete)
1/2” – 13
(13 mm)
14”
(356 mm)
11”
(279 mm)
7”
(178 mm)
5-1/2”
(140 mm)
3/4” – 10
(19 mm)
24”
(610 mm)
18”
(457 mm)
12”
(305 mm)
9”
(229 mm)
1” – 8
(25 mm)
26”
(660 mm)
20”
(508 mm)
13”
(330 mm)
10”
(254 mm)
1-1/4” – 7
(32 mm)
26”
(660 mm)
20”
(508 mm)
13”
(330 mm)
10”
(254 mm)
1-3/4” – 5
(45 mm)
50”
(1270 mm)
39”
(991 mm)
25”
(635 mm)
19-1/2”
(495 mm)
2” – 6
(51 mm)
62”
(1575 mm)
48”
(1219 mm)
31”
(787 mm)
24”
(610 mm)
  1. Center to center spacing (S) is based on minimum embedment depth (h.ef), multiplied by 3, per ACI 318 for 3000 and 6500 psi concrete, respectively.
  2. Edge Distance (E) is based on minimum embedment depth (h.ef), multiplied by 1.5, per ACI 318 for 3000 and 6500 psi concrete, respectively.Values shown apply only to standard carbon steel grade S-7 anchors

Materials

The Williams S-7 Reusable Concrete Anchor is offered in diameters ranging from 1/2”-13 UN thru 2”-6 UN and a choice of materials including ASTM A108 standard commercial grade carbon steel and ASTM A193 Grade B8 Type 304 stainless steels in anchor sizes up to 1” diameter. The anchors shall be complete with stud, cone, and expansion shell.

  1. Anchor assembly for S-7 consists of:
    • An anchor stud complying with ASTM A108 for carbon steel and ASTM A193 Grade B8 Type 304 for stainless steel.
    • A Williams cone in threaded engagement with the inner end of the anchor stud complying with ASTM A 29 for carbon steel and ASTM A193 Grade B8 Type 304 for stainless steel. The cone shall have an exterior conical surface continuous in cross section to deliver bearing pressure radially with respect to the axis of the anchor bar.
    • A Williams slotted expansion shell with an inner surface bearing on the cone, the outer surface initially of cylindrical curvature. The steel complies with ASTM A108 for carbon steel and ASTM A193 Grade B8 Type 304for stainless steel.
  2. The S9Z Setting Tool is required for installation of S-7 Reusable Concrete Anchors.

Williams S-7 anchors are specially designed with a cone that threads into the bottom of the anchor stud. This threaded portion at the bottom of the anchor governs the ultimate tensile capacity of the system, which explains why the tensile loads are lower than Williams Spin-Lock anchor systems. However, shear loading at the base plate is resisted by the full diameter of the anchor stud rather than the smaller threaded diameter at the cone/stud interface. The picture above illustrates this point. This process is necessary to provide the user with a reusable detachable anchor stud. The outer stud diameter dictates the shear strength of the anchor, while the inner stud diameter dictates the anchor tensile strength.

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