ANCHORAGE

Critical ParametersCritical Parameters

• Bolt Type

• Strength– Grade– Diameter

• LengthLength

• Density (spacing)Density (spacing)

• PlatesPlates

Bolt LengthBolt Length

Industry Rule Of Thumb: Industry Rule Of Thumb: Bolt length should be Bolt length should be half the supported span dimension.half the supported span dimension.

Bolt LengthBolt Length

Bolt DensityBolt Density

FRICTION ANCHORED SUPPORT

POINT ANCHORED SUPPORT

10’

Anchorage 1 Ton/Ft (1 Ton)

Anchorage 10 Tons

1’

Bolt DensityBolt Density

Fall of splitset supported back in an underground limestone mine

Bolt LengthBolt Length

Failure of Mechanical BoltsFailure of Mechanical Bolts

Installation Angle

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Installation Angle

Install Bolts Install Bolts Perpendicular to the Perpendicular to the

Rock Surface for Rock Surface for Pattern BoltingPattern Bolting

(Except Where Key (Except Where Key Block Bolting is Block Bolting is

Required)Required)

Pattern Boltingversus

Spot Bolting

Friction Anchored BoltsFriction Anchored Bolts

Resin Anchored BoltsResin Anchored Bolts

Surface ControlSurface Control

Primary SupportPrimary Support

Bolt Across JointsBolt Across Joints

Bolt Perpendicular To Joints

SURFACE CONTROL PLATES, CHANNELS &

MATTS

GRADES OF PLATES

K2, K3 & K4

2 = 20,000 LBS

K = LETTER DENOTES

NAME OF

MANUFACTURER

Donut Bearing Plate

Donut HeaderPlate

8” x 8” Bearing Plate

6” x 10” Low Profile Header Plate

6” x 16” Low Profile Header Plate

6” x 16” Low Dome Header Plate

6” x 6” Flat Plate

4” x 9” ChannelPlate

6” x 6” Dome Plate

6” x 6”SAF Dome Plate

MATS

USED TO CONTROL ROOF SLOUGHING

PIZZA PANS

CHANNELSUSED THE SAME AS A CROSSBAR FOR ROOF

CONTROL

TENSAR W/WO BACKING

Plate SizeSize and Type of Bearing Plate Should

Correspond to Ground Conditions

Soft Rock SkinSoft Rock Skin

Weak RockWeak Rock

Soft Rock Skin Soft Rock Skin

Large Plate(Covers More Area)

Less Damage to Surface

Large Plate(Covers More Area)

Less Damage to Surface

Small Plate(Covers Less Area)

Damage to Surface

Small Plate(Covers Less Area)

Damage to Surface

Soft Rock SkinSoft Rock Skin

Back Overstressed(Rock Falls Out)

Loose Plate-No Tension

Back Overstressed(Rock Falls Out)

Loose Plate-No Tension

PROPER INSTALLATION REQUIRESPROPER INSTALLATION REQUIRESCORRECTLY DRILLED HOLESCORRECTLY DRILLED HOLES

Hole LengthHole Length

( Resin Systems)( Resin Systems)

Too Short Loose PlateToo Short Loose Plate

Too Long Short Grout LengthToo Long Short Grout Length

Hole DiameterHole Diameter

Too Small Insertion ProblemsToo Small Insertion Problems

Too large Less AnchorageToo large Less Anchorage