Mechanical Anchors and Rebar Rock Bolts

2

Introduction .................................................................................................................. 3

Mechanical Anchors ...................................................................................................... 4

Resin Rock Bolts ........................................................................................................... 6

SN-Anchors .................................................................................................................. 8

DYWIDAG THREADBAR........................................................................................... 11

Accessories ................................................................................................................ 12

Further Information ..................................................................................................... 13

Order Information SN-Anchors ................................................................................... 14

Contents

Introduction

Anchors and rock bolts, which are commonly assigned the general term rock bolts, are used for rock reinforcement in Mining and Tunneling. Rock bolts limit the loosening of blocks out of the rock mass and shear displacements. Furthermore, the frictional force between individual rock layers is increased.

Anchors with a variable anchor length enable pre-tensioning and thus an active force transmission.

GEWI Mining Anchors and Mechanical Anchors Type ALWAG are well-established systems with variable anchor lengths. The maximum load-bearing capacity of these mechanical anchors is mainly determined by the stability of the borehole (ground characteristics), the amount of the pre-tensioning, and the design of the expansion shell.

Rock bolts such as SN-Anchors or the DYWIDAG THREADBAR are fully grouted over the whole length and are usually installed untensioned.

Generally, this does not apply to resin rock bolts, which can be actively pre-tensioned using resin cartridges with different curing times.

Which rock bolt system is the best one to use depends on a variety of factors, which have to be considered in each individual case. DYWIDAG-Systems International has longtime experience in the development, production and supply of mechanical anchors and rock bolts.

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Systematic anchoring in underground Mining and Tunneling

Doweling of rock layers in the hanging wall

Utility hangers

Simple handling and optimized installation time

Immediate loading-bearing capacity

Field-proven and reliable anchors

Unproblematic installation in aquiferous boreholes

Optimized ratio of anchor force vs. borehole diameter

Steel expansion shell Different versions available on request

Anchor shaft Highly ductile GEWI anchor steel with continuous clock-wise coarse thread Individual delivery lengths on agreement

Anchor plate Flat plate with conical through-hole

Anchor nut Constructed as one-sided convex hexagonal nut, self-locking nut, or domed nut

Continuous threaded GEWI anchor bars allow flexible length adjustments and posterior extension on site

Expansion sleeves are available for different borehole diameters

The GEWI Mining Anchor is approved for underground application by the Regional Government Arnsberg, Dep. 6 Mining and Energy in NRW, Germany

Mechanical Anchors

Fields of Application

Main Advantages

System Components GEWI Mining Anchors

Steel expansion shell Anchor shaft

Anchor nutAnchor plate

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Characeristics / Type Unit KS-145 KS-190 KS-220Nominal diameter [mm] 16.2 18 20Nominal weight [kg/m] 1.62 2.00 2.46

Nominal cross-section [mm2] 207 254 314Yield stress 1) [N/mm2] 450 670 500

Tensile stress 1) [N/mm2] 700 800 700Ultimate load 2) [kN] 145 190 220

Ultimate elongation A5 1) [%] 15 15 15Nut version 3) [] S, H K K

Borehole diameter 4) [mm] 34 - 36 44 - 47 44 - 47Approval file No. 5) [] 83.18.24.6-2004-9 62.18.24.6-2008-1 83.18.24-6-2001-9

1) Steel tendon2) Anchor system: anchor bar, plate, and nut3) H = hex nut, one-sided convex seat, S = stop nut, K = domed nut4) Standard version expansion shell5) Regional Government Arnsberg, Dep. 6 Mining and Energy in NRW, Germany

Characteristics Unit TypeDiameter [mm] 16

Thread designation [] M18Cross-sectional area [mm2] 200

Yield strength 2) [N/mm2] 360Ultimate strength 2) [N/mm2] 690

Ultimate elongation A5 2) [%] 11Ultimate load 3) [kN] 140Delivery lengths [mm] 500 - 6,000

1) Mechanical Anchors and expansion shells in other dimensions are available on request, all indicated values are nominal2) Round bar tendon3) Mechanical Anchors with cold-rolled thread, plate, washer, and nut

Drilling of an anchor borehole in accordance with the specifications, approx. 150 [mm] longer than the expansion shell anchor when installed

Introduction of the readily assembled expansion shell anchor into the borehole - the expansion shell shall fit tight into the borehole

Pre-tensioning via impact screw driver or adequate driver tool

Optional post grouting using a factory-fitted injection hose

Expansion shell Expansion shells in versions B38 and B43 available, appropriate for borehole diameters of 38 and 43 [mm]

Anchor bar Solid anchor bar, threaded on both ends Steel grade E360 according to EN 10025-2

Plate Standard version: domed plate with round hole

Nut and washer Spherical washers and driver tools available on request

Other dimensions, steel grades, and galvanized versions are available on request

Mechanical Anchors

Specifications GEWI Mining Anchors

Specifications Mechanical Anchors Type ALWAG 1) Installation Procedure

System Components Mechanical Anchors Type ALWAG

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Resin Rock Bolts

Systematic rock bolting in underground Mining

Increase of the load-bearing capacity of the rock mass, especially in coal Mining

Standard application for use in combination with DYWIDAG resin cartridges

Rock bolt shaft Mining steel Optimized thread profile for combined use with resin cartridges Pointed, with one-sided cold-rolled thread

Plate Domed plate, alternative compatible versions available on request

Nut Standard version with DYWIDAG drive nut (shear pin nut) DYWIDAG OZ-Nut available on request Installation spanners available on request

All-purpose rock bolt system - installation in jointed or soft rock

Standardized and field-proven rock bolts

Resistant against blasting vibrations

High bolting forces at short bond lengths

Fields of Application System ComponentsMain Advantages

Specifications

No. Characteristics / Type 1) Symbol Unit MN16-130 MN18-210 MN20-230 MN25-3601 Nominal diameter Da.nom [mm] 16 18 20 252 Thread [mm] M18 M20 M22 M273 Nominal cross-section anchor bar 2) S0 [mm2] 210 316 329 4684 Nominal weight anchor bar 3) m [kg/m] 1.67 2.14 2.58 3.675 Yield load anchor bar 4) Fe.nom [kN] 105 158 164 2346 Ultimate tensile load anchor bar 4) Fe.nom [kN] 134 202 240 3417 Yield stress anchor bar 5) Re.nom [N/mm2] 500 500 500 5008 Tensile stress anchor bar 5) Rm.nom [N/mm2] 640 640 730 7309 Ultimate elongation anchor bar 5) Agt [%] 10 10 10 10

10 Ultimate load anchor system 6) Fm.A.nom [kN] 130 210 230 36011 Wrench size nut SW [mm] 27 30 32 4112 Delivery lengths 7) L [mm] 600 - 1,600 600 - 1,600 600 - 2,400 600 - 2,400

1) Status: 2012-08, note: all values are subject to change; other dimensions and steel grades available on request2) Calculated from the nominal weight: S0 = 106 x m / 7,850 [kg/m3]3) Characteristic fractile value4) Calculated from the characteristic load value and nominal weight, rounded5) Mining steel type DD-BAR, modulus of elasticity: 210,000 [N/mm2]6) Nominal value ultimate system load: anchor head with cold-rolled thread, plate, and nut7) Off-size lengths are available on request

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Resin Rock Bolts

Reliable indication for a correctly installed resin rock bolt

Assembly between nut and bolt plate

Available for all resin rock bolt types

Borehole drilling Manual or automated insertion of the resin cartridges Rotary installation of the resin anchor until the installation depth has been reached

Activation of the resin cartridge by mixing the components Holding time is to be adjusted to the applied synthetic resin cartridges or valid installation instructions Tensioning of the bolts head by tightening the nut

Corrosion protection of system components may be provided by hot dip galvanizing or alternative coatings

Torque Indicators

Installation Procedure

Corrosion Protection

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SN-Anchors

Fields of Application

Field-proven rock bolt system

Effective and standardized installation

Embedding of the tension member in grout ensures optimal bond strength

Low sensitivity concerning the actual diameter of the anchor borehole

ALWAGRIP special rib geometry for optimized bond strength available on request

Rock bolt shaft Reinforcement steel B 500 B according to DIN 488, B 550 B according to NORM B 4707 or rock bolt steel FA 650/820 Pointed, with cold-rolled thread at the far end, including nut and washer Standard thread length approximately 120 [mm], maximum thread length 200 [mm] available on request Special ALWAGRIP rib geometry for increased bond available on recommendation

Plate Default bolt plate: domed, with long hole Other bolt plates in different dimensions available on request

Waher and nut Rock bolt head version with hemispherical washer available on request Optional free bolt length using a shrink tube

Main Advantages

System Components

Rock bolt shaft

PlateWasher and nut

Standard rock bolt head with plain washer and nut

Rock bolt head with hemispherical washer, plain washer, and nut

SN-Anchors, also known as mortar embedded concrete reinforcement steel anchors or Store-Norfors-Anchors (named after the first place of installation), are used for rock reinforcement in underground Mining and Tunneling.

The DYWIDAG THREADBAR is mainly used for special underground bolting works as well as for underpinnings or as utility hanger.

For special requirements in Tunneling, especially rock reinforcement in squeezing ground and large displacements directly after bolt installation, DSI also offers SN-Anchors with ALWAGRIP special rib geometry for an increased load-bearing capacity.

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SN-Anchors

Borehole drilling

Filling of the boreholes with mortar

Manual insertion of SN-Anchors into the pre-filled boreholes, fixation in the borehole using a wedge or similar device

Curing time is to be adjusted to the applied grout or valid installation instructions

Tensioning of the bolts head by tightening the nut

Installation procedure

Specifications

Compatible domed plates

No. Characteristics / Type 1) Symbol Unit SN20-180 SN25-250 SN25-330 SN28-3301 Nominal diameter Da.nom [mm] 20 25 25 282 Thread [mm] M21 M26 M26 M303 Nominal cross-section anchor bar 2) S0 [mm2] 315 490 490 6154 Nominal weight anchor bar 3) m [kg/m] 2.47 3.85 3.85 4.835 Yield load anchor bar 4) Fe.nom [kN] 173 245 319 3086 Ultimate tensile load anchor bar 4) Fm.s.nom [kN] 190 260 340 3307 Yield stress anchor bar 5) Re.nom [N/mm2] 550 500 650 5008 Tensile stress anchor bar 6) Rm.s.nom [N/mm2] 594 540 820 5409 Ultimate elongation anchor bar 5) Agt [%] 5.0 5.0 5.0 5.0

10 Ultimate load anchor system 7) Fm.A.nom [kN] 180 250 330 33011 Wrench size nut SW [mm] 36 41 41 4612 Delivery lengths 8) L [mm] 1,000 - 12,000 1,000 - 12,000 1,000 - 12,000 1,000 - 12,000

1) Status: 2012-06, note: all values are subject to change; other dimensions and steel grades available on request2) Calculated from the nominal weight: S0 = 106 x m / 7,850 [kg/m3]3) Characteristic fractile value4) Calculated from the characteristic load value and nominal weight, rounded5) Reinforcement steel B 500 B according to DIN 488, B 550 B according to NORM B 4707 or rock bolt steel FA 650/820, modulus of elasticity: 210,000 [N/mm2]6) Calculated from the ratio Rm/Re or according to manufacturer specifications7) Nominal value ultimate system load: anchor head with cold-rolled thread, plate, washer, and nut8) Off-size lengths are available on request

Characteristics / Type Symbol Unit SN20-180 SN25-250 SN25-330 SN28-330Length L [mm] 150 200 200 200

Wall thickness s [mm] 8 10 12 12Height H [mm] 32.5 32.5 32.5 32.5

Width center boring D1 [mm] 23 28 28 32Length center boring D2 [mm] 28 38 38 42

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0250

200

150

100

50

0 25 50 75 100

SN-Anchors

According to the guideline RVS 8T, Federal Minstry for Transport, Innovation and Technology, Austria

The rib geometry of conventional SN-Anchors is in accordance with the regulations of concrete steel reinforcement

Ground deformations in Tunneling usually occur immediately after the installation of SN-Anchors, which is why the requirements for bond strength development differs from reinforced concrete construction

Development of ALWAGRIP special rib geometry in accordance with the requirements for SN-Anchors in Tunneling, especially in squeezing ground conditions

Obtained rib area between 0.02 and 0.04 (cf. RVS 8T, Federal Ministry for Transport, Innovation and Technology, Austria)

Material characteristics of SN-Anchors with ALWAGRIP special rib geometry are considerably better than for similar anchors and rock bolts with concrete reinforcement ribbing

The advantages of using a steel grade with higher yield strength are observable after a curing time of 12 hours

Examination of the inner bond for two different anchor steel types depending on curing time

Results of pull-out tests after 12 hours curing time, bond length 500 [mm]

ALWAGRIP Special Rib Geometry

Tens

ion

forc

e [k

N]

Displacement [mm]

Rock bolt steel 25 [mm] FA 650/820 with ALWAGRIP special rib geometryconcrete rib steel 25 [mm] B 500 B

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DYWIDAG THREADBAR

Optimized ratio of anchor force to borehole diameter

Continuous threaded bar allows length adjustment and subsequent extension on-site

Wear-resistant coarse thread according to the requirements in underground construction

GEWI bar With right or left hand coarse thread Optional extension using couplings

Plate Domed or flat

Nut Domed or hexagonal version Eye bolts available on request

Double corrosion-protected version and free length systems with jacket tube available on request

Main Advantages

System Components

Specifications

TypeNominal diameter

[mm]Cross-sectional

area [mm2]Yield strength

[N/mm2]Tensile strength

[N/mm2]Yield load

[kN]Ultimate load

[kN]

GEWI - left-hand thread

16 201 500 550 101 11120 314 500 550 157 17325 491 500 550 246 27028 616 500 550 308 33932 804 500 550 402 44240 1,257 500 550 628 69150 1,963 500 550 982 1,080

GEWI Plus - right-hand

thread

18 254 670 800 170 20422 380 670 800 255 30425 491 670 800 329 39328 616 670 800 413 49330 707 670 800 474 56535 962 670 800 645 77043 1,452 670 800 973 1,162

57.5 2,597 670 800 1,740 2,077

Nut Plate

GEWI bar

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Accessories

Standard version: domed or flat plate

Steel grade S235 according to EN 10025-2

Custom-specific lugs for domed plates

Special plates are available on request

Plates

Length [mm]

Width [mm]

Wall thickness [mm]

Version 1)

150 150 8 C / W150 150 10 C / W180 180 8 C / W200 200 10 C / W200 200 12 C / W250 250 12 W

1) C ... cold formed calotte with oval breakout (long hole); W ... warm formed calotte with round breakout (round hole)

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Accessories

Cable and bar truss systems

Sliding nuts for anchors and rock bolts

Angle compensation discs and plates

Load indicators

Spacers

Dollies and spanners

System components in galvanized or duplex-coated versions

Mortar-Mixing pump and injection adaptors

Pull testing equipment for all types of anchors and rock bolts

Custom-specific accessories available on request

Further References

DIN 21521-1,2: Rock bolts for mining and tunnel support

DSIs installation guidelines for anchors and rock bolts

DIN 21521-1,2: Rock bolts for mining and tunnelling

EN 14490: Implementation of works in foundation engineering soil nailing

Federal Ministry of Transportation, Innovation and Technology (Ed.): Guidelines and regulations for road building: RVS 8T Technical contract conditions tunneling. 2004-08

Payer, M., Maydl, P.: Inspection report Pull-out tests of SN-Anchors. Order-No.: 77.645/08, Test date: 2008-04-22 - 2008-06-13. Technical Examination and Research Center for stability and material tests, Graz Technical University. Graz, Austria, 2008

Schubert, W. (Ed.): Recommendation Fully mortared rock bolts (SN-Anchors) Special Rib Geometry and requirements for the mortar; Institute of Rock Mechanics and Tunnelling; Graz, Austria, 1997-07

Blmel, M.: Bearing load of rock bolts in squeezing rock mass, Proceedings ISRM International Symposium EUROCK 96 Turin, Italy, Balkema Rotterdam, 1996

Blmel, M.; Schweiger, H.F.; Golser, H.: Effect of Rib Geometry on the Mechanical Behaviour of Grouted Rock Bolts, Proc. of World Tunnel Congress 97, 23rd General Assembly of the International Tunnelling Ass., Vienna, Austria, 1997

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Order Information SN-Anchors

Article Description Article No.SN-Anchor SN20-180, L = 2,000 [mm] 201310181020SN-Anchor SN20-180, L = 3,000 [mm] 201310181030SN-Anchor SN20-180, L = 4,000 [mm] 201310181040SN-Anchor SN20-180, L = 6,000 [mm] 201310181060SN-Anchor SN20-180, L = 8,000 [mm] 201310181080SN-Anchor Domed plate SN20, 150x150x08-023 [mm] 201340012008SN-Anchor Domed plate SN20, 200x200x10-023 [mm] 201340013010SN-Anchor Nut M21, SW 36 [mm] 201320011036SN-Anchor Coupling M21-M21 201330011000SN-Anchor Hemispherical washer M21, d. 23 [mm] 201350010000SN-Anchor SN25-250, L = 2,000 [mm] 201910251020SN-Anchor SN25-250, L = 3,000 [mm] 201910251030SN-Anchor SN25-250, L = 4,000 [mm] 201910251040SN-Anchor SN25-250, L = 6,000 [mm] 201910251060SN-Anchor SN25-250, L = 8,000 [mm] 201910251080SN-Anchor SN25-330, L = 2,000 [mm], ALWAGRIP 201910332020SN-Anchor SN25-330, L = 3,000 [mm], ALWAGRIP 201910332030SN-Anchor SN25-330, L = 4,000 [mm], ALWAGRIP 201910332040SN-Anchor SN25-330, L = 6,000 [mm], ALWAGRIP 201910332060SN-Anchor SN25-330, L = 8,000 [mm], ALWAGRIP 201910332080SN-Anchor Nut M26, SW 41 [mm] 201920011041SN-Anchor Coupling M26-M26, L = 90 [mm] 201930011000SN-Anchor Hemispherical washer M26, d. 26 [mm] 201950010000SN-Anchor Domed plate SN25, 150x150x08-028 [mm] 201940012008SN-Anchor Domed plate SN25, 150x150x10-028 [mm] 201940012010SN-Anchor Domed plate SN25, 200x200x10-028 [mm] 201940013010SN-Anchor Domed plate SN25, 200x200x12-028 [mm] 201940013012SN-Anchor SN28-330, L = 2,000 [mm] 202110331020SN-Anchor SN28-330, L = 3,000 [mm] 202110331030SN-Anchor SN28-330, L = 4,000 [mm] 202110331040SN-Anchor SN28-330, L = 6,000 [mm] 202110331060SN-Anchor SN28-330, L = 8,000 [mm] 202110331080SN-Anchor Nut M30, SW 46 [mm] 202120011046SN-Anchor Coupling M30-M30 202130011000SN-Anchor Hemispherical washer M30, d. 30 [mm] 202150010000SN-Anchor Domed plate SN28, 200x200x10-032 [mm] 202140013010SN-Anchor Domed plate SN28, 200x200x12-032 [mm] 202140013012

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DSI AustriaDYWIDAG-Systems International GmbHAlfred-Wagner-Strasse 14061 Pasching/Linz, AustriaPhone +43-7229-610 49 0Fax +43-7229-610 49 80 E-mail alwag@dywidag-systems.atwww.alwag.com

Please note: This brochure serves basic information purposes only. Technical data and information provided herein shall be considered non-binding and may be subject to change without notice. We do not assume any liabilityfor losses or damages attributed to the use of this technical data and any improper use of our products. Should you require further information on particular products, please do not hesitate to contact us.

ALWAG (AM 952/79), AT (AM 6138/2003), AT-SYSTEM (AM 6139/2003), DYWI (4197869), LSC (AM 4326/2008), OMEGA-BOLT (3258282), POWER SET (AM 6163/2002), and TUBESPILE (AM 4328/2008) are registered trademarks of DYWIDAG-Systems International GmbH.Combi Coat and CT-Bolt are trademarks of Vik rsta AS.DYWIDAG-Systems International GmbH is a partner of Vik rsta AS.

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