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ANCHORAGE. Critical Parameters. Bolt Type Strength Grade Diameter Length Density (spacing) Plates. Bolt Length. Industry Rule Of Thumb: Bolt length should be half the supported span dimension. Bolt Length. Bolt Density. 1’. Anchorage 1 Ton/Ft (1 Ton). Anchorage 10 Tons.
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Critical Parameters • Bolt Type • Strength • Grade • Diameter • Length • Density (spacing) • Plates
Bolt Length Industry Rule Of Thumb: Bolt length should be half the supported span dimension.
1’ Anchorage 1 Ton/Ft (1 Ton) Anchorage 10 Tons 10’ FRICTION ANCHORED SUPPORT POINT ANCHORED SUPPORT
Fall of splitset supported back in an underground limestone mine
Installation Angle Install Bolts Perpendicular to the Rock Surface for Pattern Bolting (Except Where Key Block Bolting is Required)
Pattern Bolting versus Spot Bolting
Resin Anchored Bolts Primary Support Friction Anchored Bolts Surface Control
Bolt Perpendicular To Joints
GRADES OF PLATES K2, K3 & K4 2 = 20,000 LBS K = LETTER DENOTES NAME OF MANUFACTURER
Donut Bearing Plate Donut Header Plate
8” x 8” Bearing Plate 6” x 10” Low Profile Header Plate 6” x 16” Low Profile Header Plate
6” x 6” Flat Plate 6” x 16” Low Dome Header Plate 4” x 9” Channel Plate
6” x 6” Dome Plate 6” x 6” SAF Dome Plate
Plate Size Size and Type of Bearing Plate Should Correspond to Ground Conditions
Soft Rock Skin Weak Rock
Small Plate (Covers Less Area) Damage to Surface 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 Soft Rock Skin
Back Overstressed (Rock Falls Out) Loose Plate-No Tension Back Overstressed (Rock Falls Out) Loose Plate-No Tension Soft Rock Skin
PROPER INSTALLATION REQUIRES CORRECTLY DRILLED HOLES Too Short Loose Plate Too Long Short Grout Length Too Small Insertion Problems Too large Less Anchorage Hole Length ( Resin Systems) Hole Diameter