Home > Industry Information > Fiberglass High Strength FRP Rock Anchor Bolt / FRP Rod
Fiberglass High Strength FRP Rock Anchor Bolt / FRP Rod
2021-04-19
Model NO.: high strength fiber glass FRP material threaded an
Product Name: High Modulus Composite FRP Rebar
Application: Construction, Coal Mine, Tunnel, Metro, Slope, Fo
Technique: Pultrusion Winding
Dimensions: 4-55mm
Length: 1-10m or Customized
Anti Static: 3*10000000 Ω
Tensile Strength: >600MPa
E-Modulus: 40gpa
Trademark: XINCHENG
Transport Package: Paleet
Specification: PIECE
Origin: China
Model NO.: high strength fiber glass FRP material threaded an
Product Name: High Modulus Composite FRP Rebar
Application: Construction, Coal Mine, Tunnel, Metro, Slope, Fo
Technique: Pultrusion Winding
Dimensions: 4-55mm
Length: 1-10m or Customized
Anti Static: 3*10000000 Ω
Tensile Strength: >600MPa
E-Modulus: 40gpa
Trademark: XINCHENG
Transport Package: Paleet
Specification: PIECE
Origin: China
Quick DetailsPlace of Origin: China (Mainland) Brand Name: XINCHENG
Type: Solid/ hollow / self drilling Product Name: FRP Rebar
Name: High Modulus Composite frp rebar Category: hollow grouting or solid Anchor Bolt
Application: Construction , Coal Mine, Tunnel, Metro, slope, foundation pit, etc.
Model Number: FRP glass full screw resin bolt Technique: Pultrusion winding
Surface treatment: Thread ,Anti-static/ sand-coated /customize Feature: Light Weight
Dimensions: 4-55mm Material: Fiberglass &Resin
Chemical compositon: Fiberglass & unsaturated resin / expoxy Rod density: 1.6 - 2.1g / m³
Color: Black\white\yellow\red\green or Customized Length: 1-10M or Customized
Thread: Left or Right Customized Ultimate Strain: 2%
Supply Ability: 3000 Meter/Meters per Day Anti static: 3*10000000 Ω
Tensile strength: >600MPa E-modulus: 40GPa .
Shear strength: 150MPa Certificate: ISO9001-2000,GB/T19001-2008
Fiberglass Rebar adopt glass fiber as reinforced materials and polyester resin as basic materials, through Pulled by specific traction machine, be solidified glass fiber reinforced plastic rod body with full thread under high pressure and high temperature by preformed matched die . It is made up of fiberglass anchor rod plus resin anchoring agent, tray and nut.
The Solid Bolt is used in Mining, Tunneling and Civil Engineering widely. It provides more possibilities as an alternative to metal. The GFRP Solid Bolt is manufactured with high quality GFRP material(Glassfiber Reinforced Polymer). The GFRP Solid Bolt have a high tensile load and bearing capacity with accessories, but the weight is only one quarter of metal product.
Applications
1. Mining support
2. Face bolting
3. Soil nail
4. Slope stabilization
5. Permanent application
6. Temporary support
7. Subway tunnel
8. Building construction
9. Seawall damming
10. Rock supporting
11. foundation pit wall
12. Port of foundation pit
13. Roadway support
14.Tunnel construction,etc.
Advantages:
1. All-thread (stronger bonding with the grouting material)
2. Low weight (1/4 weight of steel anchor bolt)
3. High durability ( unaffeced by acid rain, salt water, and most chemicals)
4. Strong adhesion and anchorage force
5. High corrosion resistance , anti-static
6. High torque resistance
7. 100+ years service life
8. Easy handling due to low weight
9. Fire retardant
10. Impact resistant
11. Nonconductive and thermal insulation
12. Non-magnetic electromagnetic transparency
13. Dimensional stability, Bright color
14. Low-maintenance
15. Cuttability, easy cutting
16. High torsion resistance
17. Anti-static coating (optionally)
18. Long service life
19. High tensile load
20. Deformation patterns are the same as with steel
21. Coefficient of thermal expansion more similar to concrete than that of steel
22. Direct production costs lower than similar steel bolt
23. Strongly adapt to the environment, and no emmiting the electromagnetic wave
FRP Rebar Other Features:
Non-flammable: It is non-flammable and has high thermal insulation;
Cutability : It avoids damages to cutter heads, and does not delay excavation
Save cost : Use this material as reinforcing bars for road and bridge, could reduce Secondary repair cost.
Accessory products
1. Anchor bolt : the important construction of the assembly, plays a major role in the anchor and
support.
2. The head of the anchor drill: barb can be bolt positioning in the drilled holes, the middle rod body
good.
3. Coupling: easy to manage, unlimited application range.
4. Anchor plate : bear greater stress of surrounding rock.
5. Nut: the surrounding rock stress concentrated on the pad.
6. GFRP Plate, GFRP Nut , GFRP coupler, Anchor Drill Bit, steel Nut, Steel coupler, steel plate, other types are available as requested
Glass reinforced plastic anchor rod with circular arc tooth profile FRP nut thread suit,
glass fiber reinforced plastic nut near one end of the glass fiber reinforced plastic pallet
stretch narrow neck formation, glass fiber reinforced plastic tray set it on the neck of the glass fiber reinforced plastic nut, glass reinforced plastic anchor rod in the middle of the paragraph to the polished rod structure. The utility model tensile, shear and torsion strength is strong, the production cost is low, the supporting effect is good, can be applied to all have the special circumstances of flammable and explosive.
Technical Data
| FRP Rock Bolt Test Unit | MGSL18 | NGSL20 | MGSL22 | MGSL24 | MGSL27 | |||
| Rod | Surface | Uniform appearance, no bubble and flaw | ||||||
| Nominal Diameter/mm | 18 | 20 | 22 | 24 | 27 | |||
| Tensile load/KN | 160 | 210 | 250 | 280 | 350 | |||
| Tensile Strength/MPa | 600 | 600 | 600 | 600 | 600 | |||
| Shearing strength/MPa | 150 | 150 | 150 | 150 | 150 | |||
| Torsion/Nm | 45 | 70 | 100 | 150 | 200 | |||
| Antistatic | 3*107 | 3*107 | 3*107 | 3*107 | 3*107 | |||
| Flame Resistance | Flaming | s | ≤6 | ≤6 | ≤6 | ≤6 | ≤6 | |
| s | ≤2 | ≤2 | ≤2 | ≤2 | ≤2 | |||
| Flaming burning | s | ≤60 | ≤60 | ≤60 | ≤60 | ≤60 | ||
| s | ≤12 | ≤12 | ≤12 | ≤12 | ≤12 | |||
| Plate | Plate load strength/kN | 70 | 80 | 90 | 100 | 110 | ||
| Central diameter/mm | 28±1 | 28±1 | 28±1 | 28±1 | 28±1 | |||
| Nut | Nut load strength/kN | 70 | 80 | 90 | 100 | 110 | ||
FRP Bolts/Fiber reinforced plastics bolts/GFRP Anchor Rock Bolts Parameter
| Unit | Hollow Rock bolt | Self-drilling Rock bolt | |||||
| Diameter | mm | 12/25 | 12/28 | 32/15 | 12/25 | 12/28 | 32/15 |
| External | mm | 25 | 28 | 32 | 25 | 28 | 32 |
| cross section | mm^2 | 345 | 450 | 563 | 345 | 450 | 563 |
| Thread distance | mm | 10 | 10 | 10 | 12.7 | 12.7 | 12.7 |
| Thread direction | right | right | right | left | left | left | |
| Tensile Load | kN | 230 | 300 | 380 | 250 | 330 | 400 |
| Tensile strength | Mpa | 650 | 650 | 650 | 650 | 650 | 650 |
| Torsion | Nm | 80 | 110 | 200 | 120 | 200 | 250 |
| Shear strength | MPa | 150 | 150 | 150 | 150 | 150 | 150 |
| Elongation | % | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 |
| E-modulus | Gpa | 40 | 40 | 40 | 40 | 40 | 40 |
| weight | g/m | 642 | 896 | 1156 | 642 | 896 | 1156 |
FRP rock bolt equipment
1. Productive technology: full thread FRP rock bolt body once molding
2. Production speed: fast speed, can produce ≥1.5 M per minute
3. Rod body torsion: big torsion, different rod body the torsion can be as high as 60NM-160NM
4. Rod body and nut cooperate closely, the coverall performance is good
5. Big bearing capacity, tray and nut is patented product, the maximum bearing capacity can reach more than 150KN
6. Long production time: it can continuously all day long production, trouble-free
7. Formula science, save material, the product quality is stable
8. Equipment performance in the domestic similar products leading level, simple operation, easy to control, lifelong technical
Method of application for FRP rock bolt
After the roofbolter finished drilling, remove the drill pipe, make the six-party of rock bolt installation machine insert jumbolter drill pipe connection, then make the lever genus part of compression nut insert the rock bolt installation machine, make anchoring agent into the rock bolt holes, then use the rock bolt bracing anchoring agent, at this time do propulsion leg movement, drilling machine motor not rotating, anchoring agent will be sent to the bottom of the hole, at this point to start drilling machine motor rotating, rotating rock bolt to stir anchoring agent, when the FRP rock bolt reached the bottom of the hole, stop the machine, drilling machine fast rotating to stirring anchoring agent, stirring time is set time of anchoring agent (usually 10 s ~ 15 s ), close the drilling machine, stop rotating, according to the anchoring agent curing time, general stop 30 s ~ 45 s, after anchoring agent curing, ant then make drilling machine to start rotating, screw up the nut for bottom of rock bolt, at this time drilling machine motor stop rotating, rock bolt install end
Safety matters need attention
1. When installation the rock bolt, not allowed holding the rock bolt, lest produce an accident
2. Finished the rock bolt, when the drilling machine drops, can't make the hand on the gas leg, prevent hurting hands
3. When use the jumbolter to installation tray and nut, must master the use of the drilling machine and anchoring agent, when install the nut must immediately stop the machine, otherwise it will damage FRP bolt
4. Please use the resin bolt anchoring agent that complies with safety srandards
5. Transportation store
6. In the process of product transportation shall not be cast and throw.
7. The rod body should be stored in a cool and dry place, rod body storage time no more than one year.
8. End of the anchoring can not contaminated with oil, rod body tail thread shall not damage
Technical parameters of the product
| Diameter(mm) | Length(mm) | Pallet dimension(mm) | Standard value of tensile strength(MPa) | Ultimate load of the bolt (KN) | Bearing capacity of end connection and whorl (KN) | Bolt torque (N.m) |
| 16 | 1200~1800 | 120×120×6 | ≥300 | 80 | ≥50 | ≥40 |
| 18 | 1200~2000 | 120×120×10 | ≥300 | 100 | ≥60 | ≥40 |
| 20 | 1200~3000 | 140x140x8 150×150×8 | ≥300 | 120 | ≥70 | ≥40 |
| 22 | 1600~3000 | 150×150×10 170x 170x 10 | ≥300 | 140 | ≥80 | ≥40 |
| 24 | 1800~3000 | 150×150×10 | ≥300 | 160 | ≥90 | ≥40 |
Packaging & Delivery
Packaging: Bundle with pallet, Bolts packed in bundles and accessories packed in cartons.
Packed with steel wires or other way as customers requirement.
Delivery Time: within 20 days
Lead Time ::within 20 days
Our Services
As one of the leading suppliers of pultrusion fiberglass reinforced polymer composite products, we can provide you FRP tubes, Channel, I-beam, angle, Rebar, rods,Garden stakes, gratings.
Customized shape service is available from us, just send us CAD drawing or contact us direatly. For moulds, TT 100% before making; for products, TT 30% in advance, 70% balance payment on receiving bill of lading by Email or before delivery.
Researches and development team by knowing the importance of the FRP usage in industry and construction , have successfully conducting different researches and studies projects.
Design and engineering services has been given idea from customers, and make out the thing you imaged. Specially developing on new machinary.
Istallation and construction team is experienced with installation, commissioning and training service at cutomer's factory. In this way, the customer is able to handle management of equipment themsleves soon.
Mantiance service is applied when customer cann't solve problem themselves. Mainly at equipment, software, tools…etc.
Technical support is the most importance in production. as long as frp developing, new and advanced process, material, equipments appeared. We are giving the eyes on the world frp relatived news and supply customer advanced service.
FAQ
Q: Are you a trading company or factory?
A: our factory is a FRP manufacturer in China.
Q: Can you factory customize the machine for clients?
A: yes, we can.
Q: what are you payment terms?
A: Normally, 50% as the deposit first by T/T, the rest 50% will be paid before shipping by T/T.
Q: How about after-sales service?
A: 1 year free warranty, Lifetime technical service support.
Please Contact Us
Miss: lydia
Mob: 86-13752439076 Fax: 86-22-60863016
http://www.chinainsulatingmaterial.com
Quick Details
Place of Origin: China (Mainland) Brand Name: XINCHENG
Type: Solid/ hollow / self drilling Product Name: FRP Rebar
Name: High Modulus Composite frp rebar Category: hollow grouting or solid anchor bolt
Application: Construction , Coal Mine, Tunnel, Metro, slope, foundation pit, etc.
Model Number: FRP glass full screw resin bolt Technique: Pultrusion winding
Surface treatment: Thread ,Anti-static/ sand-coated /customize Feature: Light Weight
Dimensions: 4-55mm Material: Fiberglass &Resin
Chemical compositon: Fiberglass & unsaturated resin / expoxy Rod density: 1.6 - 2.1g / m³
Color: Black\white\yellow\red\green or Customized Length: 1-10M or Customized
Thread: Left or Right Customized Ultimate Strain: 2%
Supply Ability: 3000 Meter/Meters per Day Anti static: 3*10000000 Ω
Tensile strength: >600MPa E-modulus: 40GPa .
Shear strength: 150MPa Certificate: ISO9001-2000,GB/T19001-2008
Fiberglass Rebar adopt glass fiber as reinforced materials and polyester resin as basic materials, through Pulled by specific traction machine, be solidified glass fiber reinforced plastic rod body with full thread under high pressure and high temperature by preformed matched die . It is made up of fiberglass anchor rod plus resin anchoring agent, tray and nut.
The Solid Bolt is used in Mining, Tunneling and Civil Engineering widely. It provides more possibilities as an alternative to metal. The GFRP Solid Bolt is manufactured with high quality GFRP material(Glassfiber Reinforced Polymer). The GFRP Solid Bolt have a high tensile load and bearing capacity with accessories, but the weight is only one quarter of metal product.
Applications
1. Mining support
2. Face bolting
3. Soil nail
4. Slope stabilization
5. Permanent application
6. Temporary support
7. Subway tunnel
8. Building construction
9. Seawall damming
10. Rock supporting
11. foundation pit wall
12. Port of foundation pit
13. Roadway support
14.Tunnel construction,etc.
Advantages:
1. All-thread (stronger bonding with the grouting material)
2. Low weight (1/4 weight of steel anchor bolt)
3. High durability ( unaffeced by acid rain, salt water, and most chemicals)
4. Strong adhesion and anchorage force
5. High corrosion resistance , anti-static
6. High torque resistance
7. 100+ years service life
8. Easy handling due to low weight
9. Fire retardant
10. Impact resistant
11. Nonconductive and thermal insulation
12. Non-magnetic electromagnetic transparency
13. Dimensional stability, Bright color
14. Low-maintenance
15. Cuttability, easy cutting
16. High torsion resistance
17. Anti-static coating (optionally)
18. Long service life
19. High tensile load
20. Deformation patterns are the same as with steel
21. Coefficient of thermal expansion more similar to concrete than that of steel
22. Direct production costs lower than similar steel bolt
23. Strongly adapt to the environment, and no emmiting the electromagnetic wave
FRP Rebar Other Features:
Non-flammable: It is non-flammable and has high thermal insulation;
Cutability : It avoids damages to cutter heads, and does not delay excavation
Save cost : Use this material as reinforcing bars for road and bridge, could reduce Secondary repair cost.
Accessory products
1. Anchor bolt : the important construction of the assembly, plays a major role in the anchor and
support.
2. The head of the anchor drill: barb can be bolt positioning in the drilled holes, the middle rod body
good.
3. Coupling: easy to manage, unlimited application range.
4. Anchor plate : bear greater stress of surrounding rock.
5. Nut: the surrounding rock stress concentrated on the pad.
6. GFRP Plate, GFRP Nut , GFRP Coupler, Anchor Drill Bit, steel Nut, Steel coupler, steel plate, other types are available as requested
Glass reinforced plastic anchor rod with circular arc tooth profile FRP nut thread suit,
glass fiber reinforced plastic nut near one end of the glass fiber reinforced plastic pallet
stretch narrow neck formation, glass fiber reinforced plastic tray set it on the neck of the glass fiber reinforced plastic nut, glass reinforced plastic anchor rod in the middle of the paragraph to the polished rod structure. The utility model tensile, shear and torsion strength is strong, the production cost is low, the supporting effect is good, can be applied to all have the special circumstances of flammable and explosive.
Technical Data
| FRP Rock Bolt Test Unit | MGSL18 | NGSL20 | MGSL22 | MGSL24 | MGSL27 | |||
| Rod | Surface | Uniform appearance, no bubble and flaw | ||||||
| Nominal Diameter/mm | 18 | 20 | 22 | 24 | 27 | |||
| Tensile load/KN | 160 | 210 | 250 | 280 | 350 | |||
| Tensile Strength/MPa | 600 | 600 | 600 | 600 | 600 | |||
| Shearing strength/MPa | 150 | 150 | 150 | 150 | 150 | |||
| Torsion/Nm | 45 | 70 | 100 | 150 | 200 | |||
| Antistatic | 3*107 | 3*107 | 3*107 | 3*107 | 3*107 | |||
| Flame Resistance | Flaming | s | ≤6 | ≤6 | ≤6 | ≤6 | ≤6 | |
| s | ≤2 | ≤2 | ≤2 | ≤2 | ≤2 | |||
| Flaming burning | s | ≤60 | ≤60 | ≤60 | ≤60 | ≤60 | ||
| s | ≤12 | ≤12 | ≤12 | ≤12 | ≤12 | |||
| Plate | Plate load strength/kN | 70 | 80 | 90 | 100 | 110 | ||
| Central diameter/mm | 28±1 | 28±1 | 28±1 | 28±1 | 28±1 | |||
| Nut | Nut load strength/kN | 70 | 80 | 90 | 100 | 110 | ||
FRP bolts/Fiber reinforced plastics bolts/GFRP Anchor Rock Bolts Parameter
| Unit | Hollow Rock bolt | Self-drilling Rock bolt | |||||
| Diameter | mm | 12/25 | 12/28 | 32/15 | 12/25 | 12/28 | 32/15 |
| External | mm | 25 | 28 | 32 | 25 | 28 | 32 |
| cross section | mm^2 | 345 | 450 | 563 | 345 | 450 | 563 |
| Thread distance | mm | 10 | 10 | 10 | 12.7 | 12.7 | 12.7 |
| Thread direction | right | right | right | left | left | left | |
| Tensile Load | kN | 230 | 300 | 380 | 250 | 330 | 400 |
| Tensile strength | Mpa | 650 | 650 | 650 | 650 | 650 | 650 |
| Torsion | Nm | 80 | 110 | 200 | 120 | 200 | 250 |
| Shear strength | MPa | 150 | 150 | 150 | 150 | 150 | 150 |
| Elongation | % | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 |
| E-modulus | Gpa | 40 | 40 | 40 | 40 | 40 | 40 |
| weight | g/m | 642 | 896 | 1156 | 642 | 896 | 1156 |
FRP rock bolt equipment
1. Productive technology: full thread FRP rock bolt body once molding
2. Production speed: fast speed, can produce ≥1.5 M per minute
3. Rod body torsion: big torsion, different rod body the torsion can be as high as 60NM-160NM
4. Rod body and nut cooperate closely, the coverall performance is good
5. Big bearing capacity, tray and nut is patented product, the maximum bearing capacity can reach more than 150KN
6. Long production time: it can continuously all day long production, trouble-free
7. Formula science, save material, the product quality is stable
8. Equipment performance in the domestic similar products leading level, simple operation, easy to control, lifelong technical
Method of application for FRP rock bolt
After the roofbolter finished drilling, remove the drill pipe, make the six-party of rock bolt installation machine insert jumbolter drill pipe connection, then make the lever genus part of compression nut insert the rock bolt installation machine, make anchoring agent into the rock bolt holes, then use the rock bolt bracing anchoring agent, at this time do propulsion leg movement, drilling machine motor not rotating, anchoring agent will be sent to the bottom of the hole, at this point to start drilling machine motor rotating, rotating rock bolt to stir anchoring agent, when the FRP rock bolt reached the bottom of the hole, stop the machine, drilling machine fast rotating to stirring anchoring agent, stirring time is set time of anchoring agent (usually 10 s ~ 15 s ), close the drilling machine, stop rotating, according to the anchoring agent curing time, general stop 30 s ~ 45 s, after anchoring agent curing, ant then make drilling machine to start rotating, screw up the nut for bottom of rock bolt, at this time drilling machine motor stop rotating, rock bolt install end
Safety matters need attention
1. When installation the rock bolt, not allowed holding the rock bolt, lest produce an accident
2. Finished the rock bolt, when the drilling machine drops, can't make the hand on the gas leg, prevent hurting hands
3. When use the jumbolter to installation tray and nut, must master the use of the drilling machine and anchoring agent, when install the nut must immediately stop the machine, otherwise it will damage FRP bolt
4. Please use the resin bolt anchoring agent that complies with safety srandards
5. Transportation store
6. In the process of product transportation shall not be cast and throw.
7. The rod body should be stored in a cool and dry place, rod body storage time no more than one year.
8. End of the anchoring can not contaminated with oil, rod body tail thread shall not damage
Technical parameters of the product
| Diameter(mm) | Length(mm) | Pallet dimension(mm) | Standard value of tensile strength(MPa) | Ultimate load of the bolt (KN) | Bearing capacity of end connection and whorl (KN) | Bolt torque (N.m) |
| 16 | 1200~1800 | 120×120×6 | ≥300 | 80 | ≥50 | ≥40 |
| 18 | 1200~2000 | 120×120×10 | ≥300 | 100 | ≥60 | ≥40 |
| 20 | 1200~3000 | 140x140x8 150×150×8 | ≥300 | 120 | ≥70 | ≥40 |
| 22 | 1600~3000 | 150×150×10 170x 170x 10 | ≥300 | 140 | ≥80 | ≥40 |
| 24 | 1800~3000 | 150×150×10 | ≥300 | 160 | ≥90 | ≥40 |
Packaging & Delivery
Packaging: Bundle with pallet, Bolts packed in bundles and accessories packed in cartons.
Packed with steel wires or other way as customers requirement.
Delivery Time: within 20 days
Lead Time ::within 20 days
Our Services
As one of the leading suppliers of pultrusion fiberglass reinforced polymer composite products, we can provide you FRP tubes, Channel, I-beam, angle, Rebar, rods,Garden stakes, gratings.
Customized shape service is available from us, just send us CAD drawing or contact us direatly. For moulds, TT 100% before making; for products, TT 30% in advance, 70% balance payment on receiving bill of lading by Email or before delivery.
Researches and development team by knowing the importance of the FRP usage in industry and construction , have successfully conducting different researches and studies projects.
Design and engineering services has been given idea from customers, and make out the thing you imaged. Specially developing on new machinary.
Istallation and construction team is experienced with installation, commissioning and training service at cutomer's factory. In this way, the customer is able to handle management of equipment themsleves soon.
Mantiance service is applied when customer cann't solve problem themselves. Mainly at equipment, software, tools…etc.
Technical support is the most importance in production. as long as frp developing, new and advanced process, material, equipments appeared. We are giving the eyes on the world frp relatived news and supply customer advanced service.
FAQ
Q: Are you a trading company or factory?
A: our factory is a FRP manufacturer in China.
Q: Can you factory customize the machine for clients?
A: yes, we can.
Q: what are you payment terms?
A: Normally, 50% as the deposit first by T/T, the rest 50% will be paid before shipping by T/T.
Q: How about after-sales service?
A: 1 year free warranty, Lifetime technical service support.
Please Contact Us
Miss: lydia
Mob: 86-13752439076 Fax: 86-22-60863016
http://www.chinainsulatingmaterial.com
Silver color rebar coupler, which is different from black color rebar coupler. It has been processed with strip ex-circle.
The coupler surface is silver and light.
As a professional manufacturer of rebar couplers and a leader in this
industry in China, Baoding Jindi Machinery Co.,
Ltd. is famous for our level-headed operations.
Silver Color Rebar Couplers, Rebar Coupler In Construction Projects, Rebar Coupler For Construction Material, Parallel Thread Screw Rebar Coupler
Scaffold Accessories,Bulding Projects Accessories Co., Ltd. http://www.rebarconnectors.com