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Grout Bonded (Multiple Corrosion Protection) Rock & Soil Anchor Systems

Multiple Corrosion Protection Anchor

Williams standard grout bonded rock & soil anchors consist of a plain or epoxy coated bar, grouted in an oversized drill hole. Centralizers should be used to assure good grout cover (approximately 25 mm) around the bar. Where anchors will penetrate aggressive soils that are low in pH value (<5.5) and high in sulfate, additional corrosion protection may be desirable. The degree of protection should be matched against the aggressivity of the environment and the expected life of the anchorage system. Williams Multiple Corrosion Protection (MCP) systems offer increasing barriers against corrosion attack for confidence in permanent anchorage in all ground environments. Williams protective outer end caps may also be used to seal the nut and washer from the environment when the outer end of the anchorage will not be encased in concrete.

Typically, Williams MCP anchors are supplied in 150 KSI All-Thread Grade (as shown below) and used in various applications such as externally supported earth structures and tension tie-down systems.

All-Thread Bar Structural Properties
Bar Type Yield
Stress
Ultimate
Stress
Typical
Elongation
Reduction
of Area

150 KSI All-Thead-Bar

128 KSI
(881 Mpa)
150 KSI
(1034 Mpa)
4% over 20
bar diameters
20%

Grade 75 All-Thread Rebar

75 KSI
(517 Mpa)
100 KSI
(698 Mpa)
7% - 9%
in 8" bar
- - -
 
     

Ultimate Bond Strength
Per Linear Foot of Cement Grout by Diameter of Drill Hole

Rock Type

A. Coral
B. Soft Limestone
C. Dolomitic Limestone
D. Soft Shale
E. Sandstone
F. Granite & Basalt
G. Hard Shale & Slate
H. Concrete

Notes: If overall length is over 50' (or 40' for 1-3/4" and 2-1/2" diameters), anchor coupling should be located in bond zone with field-applied barrier, such as heat shrink tube installed across splice joint. At minimum drill hole size, centralizers will only fit around anchor in the bond zone.
Drill hole diameters and bond lengths are based on geologic conditions. Consult your geotechnical engineer for recommendations.

Multiple Corrosion Protection I - Class 2 Protection (per PTI)

Two barriers around plain bar in free-stress zone plus drill hole grout.

  • Plain, galvanized or epoxy coated bar
  • Smooth PVC sleeve over bar in free-stressing zone
  • Grease or grout filled smooth PVC sleeve over bar in the free-stress zone
  • Unit is centered in drill hole grout with centralizers
  • Typically made with 150 KSI All-Thread-Bar or Grade 75 All-Thread Rebar
Nominal Bar
Diameter
Min. Drill
Hole Dia.
Common Drill Hole
Dia. Range
1"
(26 mm)
3-1/2"
(89 mm)
3-1/2" to 5"
(89 to 127 mm)
1-1/4"
(32 mm)
3-1/2"
(89 mm)
3-1/2" to 5"
(89 to 127 mm)
1-3/8"
(36 mm)
4"
(102 mm)
4" to 6"
(102 to 152 mm)
1-3/4"
(45 mm)
4-1/2"
(114 mm)
4-1/2" to 7"
(114 to 178 mm)
2-1/2"
(64 mm)
5"
(127 mm)
5" to 8"
(127 to 203 mm)
Free-Stressing Zone Bond Zone
Free-Stressing Zone of a PTI Class 2 Double Corrosion Protection Anchor Bond Zone of a PTI Class 2 Double Corrosion Protection Anchor
Shown with 150 KSI All-Thread Bar
Note: Drill hole diameters and bond lengths
are based on geological conditions. Consult
your geotechnical engineer for recommendations.

Multiple Corrosion Protection II - Class 1 Protection (per PTI)

Two barriers around plain bar full length plus drill hole grout

  • Bar engulfed in pre-grouted poly corrugated tube in the bond anchorage zone
  • Smooth PVC sleeve over bar in free-stressing zone
  • Grease or grout filled smooth PVC sleeve over bar in the free stress zone
  • Unit is centered in drill hole by centralizers and surrounded by grout
  • Typically made with 150 KSI-All-Thread Bar or Grade 75 All-Thread Rebar
Nominal Bar
Diameter
Min. Drill
Hole Dia.
Common Drill Hole
Dia. Range
1"
(26 mm)
3-1/2"
(89 mm)
3-1/2" to 5"
(89 to 127 mm)
1-1/4"
(32 mm)
3-1/2"
(89 mm)
3-1/2" to 5"
(89 to 127 mm)
1-3/8"
(36 mm)
4"
(102 mm)
4" to 6"
(102 to 152 mm)
1-3/4"
(45 mm)
4-1/2"
(114 mm)
4-1/2" to 7"
(114 to 178 mm)
2-1/2"
(64 mm)
5"
(127 mm)
5" to 8"
(127 to 203 mm)
Free-Stressing Zone Bond Zone
Free-Stressing Zone of a PTI Class 1 Double Corrosion Protection Anchor Bond Zone of a PTI Class 1 Double Corrosion Protection Anchor
Shown with 150 KSI All-Thread Bar
Note: Drill hole diameters and bond lengths
are based on geological conditions. Consult
your geotechnical engineer for recommendations.

Multiple Corrosion Protection III - Class 1 Protection (per PTI)

 

Three barriers around plain bar in free-stress zone, two barriers in bond zone, plus rill hole grout

  • Bar engulfed in pre-grouted poly corrugated tube in the bond anchorage zone and the free-stressing zone.
  • Smooth PVC sleeve over the corrugated tube in the free-stressing zone
  • Unit is centered in drill hole by centralizer and surrounded by grout
  • Galvanized plate
  • Protective end cap over nut and washer
  • Typically made with 150 KSI All-Thread-Bar or Grade 75 All-Thread Rebar
Nominal Bar
Diameter
Min. Drill
Hole Dia.
Common Drill Hole
Dia. Range
1"
(26 mm)
4-1/2"
(114 mm)
4-1/2" to 6"
(114 to 152 mm)
1-1/4"
(32 mm)
4-1/2"
(114 mm)
4-1/2" to 6"
(114 to 152 mm)
1-3/8"
(36 mm)
4-1/2"
(114 mm)
4-1/2" to 6"
(114 to 152 mm)
1-3/4"
(45 mm)
7"
(178 mm)
7" to 8"
(178 to 203 mm)
2-1/2"
(64 mm)
8"
(203 mm)
8" to 10"
(203 to 254 mm)
Free-Stressing Zone Bond Zone
Free-Stressing Zone of a PTI Class 1 Double Corrosion Protection Anchor Bond Zone of a PTI Class 1 Double Corrosion Protection Anchor
Shown with 150 KSI All-Thread Bar
Note: Drill hole diameters and bond lengths
are based on geological conditions. Consult
your geotechnical engineer for recommendations.

Multiple Corrosion Protection Anchor Specifications
For a detailed breakdown of the parts and components involved in MCP anchoring, click on the image to the right. Grout Bonded Ground Anchor Specifications