Mechanical Anchors and Rebar Rock Bolts

Transcription

1 Mechanical Anchors and Rebar Rock Bolts

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3 Contents Introduction... 3 Mechanical Anchors... 4 Resin Rock Bolts... 6 SN-Anchors... 8 DYWIDAG THREADBAR Accessories Further Information Order Information SN-Anchors 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 wellestablished systems with variable anchor lengths. The maximum load-bearing capacity of these mechanical anchors is mainly determined by the stability of the borehole, 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 pretensioned 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. 3

4 Mechanical Anchors Fields of Application Systematic anchoring in underground Mining and Tunneling Doweling of rock layers in the hanging wall Utility hangers Main Advantages 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 Continuous threaded 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 System Components GEWI Mining Anchors Steel expansion shell Anchor shaft Highly ductile GEWI anchor steel with continuous clock-wise coarse thread Individual delivery lengths upon agreement Anchor plate Flat plate with conical through-hole Anchor nut Constructed as one-sided convex hexagonal nut, self-locking nut, or domed nut Steel expansion shell Anchor shaft Anchor plate Anchor nut 4

5 Mechanical Anchors Specifications GEWI Mining Anchors Characeristics/Type Unit KS-145 KS-190 KS-220 Nominal diameter [mm] Nominal weight [kg/m] Nominal cross-section [mm 2 ] Yield stress 1) [N/mm 2 ] Tensile stress 1) [N/mm 2 ] Ultimate load 2) [kn] Ultimate elongation A 1) 5 [%] Nut version 3) [ ] S, H K K Borehole diameter 4) [mm] Approval file No. 5) [ ] ) Steel tendon 2) Anchor system: anchor bar, plate, and nut 3) H = hex nut, one-sided convex seat, S = stop nut, K = domed nut 4) Standard version expansion shell 5) Bezirksregierung Arnsberg, Abt. 6 Bergbau und Energie, NRW System Components Mechanical Anchors Type ALWAG 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 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 Specifications Mechanical Anchors Type ALWAG 1) Diameter [mm] 16 Thread designation [ ] M18 Cross-sectional area [mm 2 ] 200 Yield strength 2) [N/mm 2 ] 360 Ultimate strength 2) [N/mm 2 ] 690 Ultimate elongation A 2) 5 [%] 11 Ultimate load 3) [kn] 140 Delivery lengths [mm] 500-6,000 1) Mechanical Anchors and expansion shells in other dimensions are available on request, all indicated values are nominal 2) Round bar tendon 3) Mechanical Anchors with cold-rolled thread, plate, washer, and nut Installation Procedure 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 5

6 Resin Rock Bolts Fields of Application 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 Main Advantages Adaptable 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 System Components 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 Specifications No. Characteristics/Type 1) Symbol Unit MN MN MN MN Nominal diameter D a.nom [mm] Thread [mm] M18 M20 M22 M27 3 Nominal cross-section anchor bar 2) S 0 [mm 2 ] Nominal weight anchor bar 3) m [kg/m] Yield stress anchor bar 4) F eh.nom [kn] Yield load anchor bar 4) F m.s.nom [kn] Tensile stress anchor bar 5) R eh.nom [N/mm 2 ] Ultimate tensile load anchor bar 5) R m.s.nom [N/mm 2 ] Ultimate elongation anchor bar 5) A gt [%] Ultimate load anchor system 6) F m.a.nom [kn] Wrench size nut SW [mm] Delivery lengths 7) L [mm] 600-1, , , ,400 1) Status: , note: all values are subject to change; other dimensions and steel grades available on request 2) Calculated from the nominal weight: S 0 = 10 6 x m / 7,850 [kg/m 3 ] 3) Characteristic fractile value 4) Calculated from the characteristic load value and nominal weight, rounded 5) Mining steel type DD-BAR, modulus of elasticity: 205,000 [N/mm 2 ] 6) Nominal value ultimate system load: anchor head with cold-rolled thread, plate, and nut 7) Off-size lengths are available on request 6

7 Resin Rock Bolts Torque Indicators Reliable indication for a correctly installed resin rock bolt Assembly between nut and bolt plate Available for all resin rock bolt types Corrosion Protection Corrosion protection of system components may be provided by hot dip galvanizing or alternative coatings Installation Procedure 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 bolt s head by tightening the nut 7

8 SN-Anchors Fields of Application 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. 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. The DYWIDAG THREADBAR is mainly used for special underground bolting works as well as for underpinnings or as utility hanger. Main Advantages Field-proven rock bolt system Effective and standardized installation Embedding of the tension member in grout guarantees optimal bond strength Low sensitivity concerning the actual diameter of the anchor borehole ALWAGRIP special rib geometry for optimized bond strength available on request System Components Rock bolt shaft Standard rock bolt head with plain washer and nut Plate Washer and nut Rock bolt shaft Reinforcement steel B 500 B according to DIN 488, B 550 B according to ÖNORM B 4707 or rock bolt steel FA 650/820 Sharpened, 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 upon 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 Rock bolt head with hemispherical washer, plain washer, and nut 8

9 SN-Anchors Specifications SN-Anchors No. Characteristics/Type 1) Symbol Unit SN SN SN SN Nominal diameter D a.nom [mm] Thread [mm] M21 M26 M26 M30 3 Nominal cross-section anchor bar 2) S 0 [mm 2 ] Nominal weight anchor bar 3) m [kg/m] Yield stress anchor bar 4) F eh.nom [kn] Yield load anchor bar 4) F m.s.nom [kn] Tensile stress anchor bar 5) R eh.nom [N/mm 2 ] Ultimate tensile load anchor bar 6) R m.s.nom [N/mm 2 ] Ultimate elongation anchor bar 5) A gt [%] Ultimate load anchor system 7) F m.a.nom [kn] Wrench size nut SW [mm] Delivery lengths 8) L [mm] 1,000-12,000 1,000-12,000 1,000-12,000 1,000-12,000 1) Status: , note: all values are subject to change; other dimensions and steel grades available on request 2) Calculated from the nominal weight: S 0 = 10 6 x m / 7,850 [kg/m 3 ] 3) Characteristic fractile value 4) Calculated from the characteristic load value and nominal weight, rounded 5) Reinforcement steel B 500 B according to DIN 488, B 550 B according to ÖNORM B 4707 or rock bolt steel FA 650/820, modulus of elasticity: 205,000 [N/mm 2 ] 6) Calculated from the ratio Rm/Reh or according to manufacturer specifications 7) Nominal value ultimate system load: anchor head with cold-rolled thread, plate, washer, and nut 8) Off-size lengths are available on request Compatible domed plates Characteristics/Type Symbol Unit SN SN SN SN Length L [mm] Wall thickness s [mm] Height H [mm] Width center boring D1 [mm] Length center boring D2 [mm] Installation procedure 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 bolt s head by tightening the nut 9

10 SN-Anchors ALWAGRIP Special Rib Geometry According to the guideline RVS 8T, Federal Minstry for Transport, Innovation and Technology, Austria Installation Procedure 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 24 hours Examination of the inner bond between two different anchor steel types depending on curing time Results of pull-out tests after 12 hours curing time, bond length 500 [mm] Pull force [kn] Displacement [mm] Rock bolt steel Ø 25 mm FA 650/820 with ALWAGRIP special rib geometry concrete rib steel Ø 25 mm B 500 B 10

11 SN-Anchors DYWIDAG THREADBAR Nut Plate Main Advantages Optimized ratio of anchor force to borehole diameter Continuous threaded bar allows length adjustment and subsequent on-site extension Wear-resistant coarse thread according to the requirements in underground construction GEWI bar System Components 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 construction and free length systems with jacket tube available upon request Specifications Type GEWI - lefthand thread GEWI Plus - right-hand thread Nominal diameter [mm] Cross-sectional area [mm 2 ] Yield strength [N/mm 2 ] Tensile strength [N/mm 2 ] Yield load [kn] Ultimate load [kn] , , , , , , ,740 2,077 11

12 Accessories Plates Standard version: domed or flat plate Steel grade S235 according to EN Custom-specific lugs for domed plates Special plates are available upon request Length [mm] Width [mm] Wall thickness [mm] Version 1) C / W C / W C / W C / W C / W W 1) C... cold formed calotte with oval breakout (long hole); W... warm formed calotte with round breakout (round hole) 12

13 Accessories Custom-specific accessories available upon request Cable and bar truss systems Domed ball washers Sliding nuts for anchors and rock bolts Angle compensation discs and plates Roof trusses and underpinnings 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 Further References DIN DSI s installation guidelines for anchors and rock bolts DIN ,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 Payer, M., Maydl, P.: Inspection report Pull-out tests of SN-Anchors. Order-No.: /08, Test date: Technical Examination and Research Center for stability and material tests, Technical University of Graz. Graz, 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, Blümel, M.: Bearing load of rock bolts in squeezing rock mass, Proceedings ISRM International Symposium EUROCK 96 Turin, Balkema Rotterdam, 1996 Blümel, M.; Schweiger, H.F.; Golser, H.: Effect of Rib Geometry on the Mechanical Behaviour of Grouted Rock Bolts, World Tunnel Congress 97, 23 rd General Assembly of the International Tunnelling Ass., Vienna,

14 Order Information SN-Anchors Article description Article No. SN-Anchor SN20-180, L = 2,000 [mm] SN-Anchor SN20-180, L = 3,000 [mm] SN-Anchor SN20-180, L = 4,000 [mm] SN-Anchor SN20-180, L = 6,000 [mm] SN-Anchor SN20-180, L = 8,000 [mm] SN-Anchor Domed plate SN20, 150x150x [mm] SN-Anchor Domed plate SN20, 200x200x [mm] SN-Anchor Nut M21, SW 36 [mm] SN-Anchor Coupling M21-M SN-Anchor Hemispherical washer M21, d. 23 [mm] SN-Anchor SN25-250, L = 2,000 [mm] SN-Anchor SN25-250, L = 3,000 [mm] SN-Anchor SN25-250, L = 4,000 [mm] SN-Anchor SN25-250, L = 6,000 [mm] SN-Anchor SN25-250, L = 8,000 [mm] SN-Anchor SN25-330, L = 2,000 [mm], ALWAGRIP SN-Anchor SN25-330, L = 3,000 [mm], ALWAGRIP SN-Anchor SN25-330, L = 4,000 [mm], ALWAGRIP SN-Anchor SN25-330, L = 6,000 [mm], ALWAGRIP SN-Anchor SN25-330, L = 8,000 [mm], ALWAGRIP SN-Anchor Nut M26, SW 41 [mm] SN-Anchor Coupling M26-M26, L = 90 [mm] SN-Anchor Hemispherical washer M26, d. 26 [mm] SN-Anchor Domed plate SN25, 150x150x [mm] SN-Anchor Domed plate SN25, 150x150x [mm] SN-Anchor Domed plate SN25, 200x200x [mm] SN-Anchor Domed plate SN25, 200x200x [mm] SN-Anchor SN28-330, L = 2,000 [mm] SN-Anchor SN28-330, L = 3,000 [mm] SN-Anchor SN28-330, L = 4,000 [mm] SN-Anchor SN28-330, L = 6,000 [mm] SN-Anchor SN28-330, L = 8,000 [mm] SN-Anchor Nut M30, SW 46 [mm] SN-Anchor Coupling M30-M SN-Anchor Hemispherical washer M30, d. 30 [mm] SN-Anchor Domed plate SN28, 200x200x [mm] SN-Anchor Domed plate SN28, 200x200x [mm]

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16 DSI Austria DYWIDAG-Systems International GmbH Alfred-Wagner-Strasse Pasching/Linz, Austria Phone Fax alwag@dywidag-systems.at 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 liability for 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 " ( ), "LSC" (AM 4326/2008), "OMEGA-BOLT " ( ), "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 Ørsta AS. DYWIDAG-Systems International GmbH is a partner of Vik Ørsta AS. Austria Argentina Australia belgium Bosnia and herzegovina Brazil Canada Chile Colombia Costa Rica Croatia Czech republic Denmark Egypt estonia Finland France Germany Greece GUATEMALA HONDURAS Hong Kong Indonesia Italy Japan Korea Lebanon Luxembourg Malaysia Mexico Netherlands Norway Oman Panama Paraguay Peru POLAND Portugal Qatar Saudi Arabia singapore South Africa Spain Sweden Switzerland Taiwan Thailand Turkey United Arab Emirates United kingdom Uruguay USA Venezuela /12.12-web he