Grout Bonded (Multiple Corrosion Protection) Rock & Soil Anchor Systems
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.
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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
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Free-Stressing Zone | Bond Zone | ||||||||||||||||||
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
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Free-Stressing Zone | Bond Zone | ||||||||||||||||||
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
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Free-Stressing Zone | Bond Zone | ||||||||||||||||||
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. |