Dextra - Ground Engineering Technical Solutions by Dextra Group

GROUND Engineering Excavations • Slopes Stabilization • Tunneling • Mining • Foundations

www.dextragroup.com

Vision To be a global leader in engineering, manufacturing and delivery of high value added quality products and services for the construction industry.

Mission To achieve customer recognition and stakeholder satisfaction by committing to the highest level of performance with integrity, creativity and a passion for results.

Value Customer Recognition, Integrity & Transparency, Passion for results, Creativity & Agility, Commitment & Accountability.

| DEXTRA | G r o u n d E n g i n e e r i n g

Established since 1983, Dextra is a leading manufacturer and distributor of engineered construction products for the building and civil industries. Dextra has developed for the past fifteen years a unique range of high-performance bar systems composed of both steel and composite materials (FRP), suitable for a variety of applications in ground anchoring, concrete tensioning, roof and facade support. The combination of our in-house engineering expertise and design capability with modern manufacturing facilities has allowed us to participate in the supply of very large construction projects in ground engineering such as Doha Metro Musheireb station, the largest subway station in the world, and Al Sadd Metro Station, as well as

Engineering

building excavation such as Sheraton Hotel Car park in Qatar. Thanks to modern production facilities, our in-house laboratories and our ISO-certified quality systems, Dextra teams are able to control and maintain a high level of quality in all system components, guaranteeing full compliance with the project specifications and customer satisfaction from design stage to delivery and installation.

Content Our Expertise

4-5

Glossary & Applications

6-7

Material Specifications

8-9

Production

Ground Anchors 10-15 Selection 11 Active Anchor 12-13 Passive Anchor 14-15 Rock-Bolts 16-23 Selection 17 Rock-Bolt 18-19 Self-Drilling Rock-Bolt 20-21 Mechanical Bolt 22 Expandable Friction Bolt 23 Micropiles Worldwide References

24-25 26-27

Expertise w w w. d e x t r a g r o u p . c o m | DEXTRA | 3

| W o r l d w i d e R e f e r e n c e s | | M i c r o p i l e s | | R o c k - B o l t s | | G r o u n d A n c h o r s | | M a t e r i a l S p e c i f i c a t i o n s || G l o s s a r y & A p p l i c a t i o n s | | O u r E x p e r t i s e | | A b o u t U s |

About Us

| DEXTRA | G r o u n d E n g i n e e r i n g

DETERMINATION OF THE RIGHT SOLUTION Dextra can guide you step-by-step in selecting the most appropriate and cost effective

Identification of need

solution for your project. Our guidance is based on 30 years experience in managing large-scale & complex projects. We offer a wide ranging and unique portfolio of solutions based on both Steel & FRP technologies.

SYSTEM OPTIMIZATION AND CUSTOMIZATION Dextra has developped over the years a comprehensive standard range of components

Design & Engineering

that allows a quick adjustment and customization of our products for a truly optimized project solution. Should the time frame allow it, Dextra teams can also engineer, develop and produce taylor-made solutions.

TOTAL CONTROL OVER MANUFACTURING Dextra has significant experience in developping and manufacturing its own products over many years. Beyond our own facilities and ISO-certified quality assurance

Manufacturing & Quality

processes, all of our suppliers are also regularly audited by our team of engineers in order to ensure quality compliance and drive continuous improvement. Inspections prior to delivery are arranged in our own factory, or in partner laboratories when required.

SUPPLY CHAIN MANAGEMENT We understand like no one else the importance of having the right product, at the right place and at the right time. Thanks to our network, Dextra is able to organize local

Logistic

storage to serve you with shorter lead-times when needed. When time is an issue, we are also able to offer acceleration schemes to expedite our solutions in order to prevent site delays.

ON-SITE SERVICE & SUPPORT We believe that the product delivery is only the beginning of the journey for our customers. Dextra international experts are also able to accompany you during each

Installation & Testing

step of onsite installation until you are truly satistifed with our solutions.

w w w. d e x t r a g r o u p . c o m | DEXTRA | 5

Our Expertise

Glossary Ground Anchor

Rock-Bolt

A ground or earth anchor is an installation in the ground which is capable of

A long anchor bolt, for stabilizing rock, which

transmitting an applied load to a local bearing stratum. The tensile element of

has usually been excavated. Rock bolts are

a ground anchor is typically a steel bar, FRP bar or strands.

often used in tunnels or rock cuts. They transfer

Soil Anchor

loads from the unstable rock exterior, to the confined and much more stable interior of the

A ground anchor installed in “SOIL” (soft ground).

rock mass.

Rock Anchor

Rock Dowel

A ground anchor installed in “ROCK” (hard ground).

Active Anchor An anchor which is post-tensioned from the external face of the ground immediately after installation, and is usually designed to help prevent deformation of the ground or retained structure. It has a free length and a bonded length.

Passive Anchor An anchor which is not pre-tensioned. Applied loads are transmitted from the ground or ground structure directly. A passive anchor does not usually have a free (unbonded) length of tendon.

Temporary Anchor An anchor with a design life less than two years.

Passive reinforcing elements inserted into predrilled holes in rock and bonded in place with grout. Can be temporary or permanent.

Hollow Rock Bolt A rock-bolt using a hollow bar which acts both as an anchor and a grouting pipe.

Self-Drilling Anchor A hollow anchor bar with end drill bit, allowing drilling, flushing, grouting and anchoring in one operation. Can be temporary or permanent.

Expandable Friction Bolt A bolt made of a deformed steel tube that is

Permanent Anchor

expanded by injecting high-pressure water.

An anchor with a design life greater than two years.

Mechanical Bolt

The design life of “semi-permanent” anchors, should be defined by the consultant, but is usually in the range of five to ten years.

Soil Nail A temporary or permanent, passive anchor, installed into the ground. A typical application is slope stabilization.

Tie-Back

A non-grouted active anchor using an expansion shell to create a point-anchor at the bottom of the hole, while tensioning is performed at the top of the hole, usually using a plate and nut.

Micropile Also known as minipiles, micropiles are deep

An anchor, usually horizontal or nearly horizontal, used to reinforce retaining

foundation elements constructed using high-

walls for stability. One end of the tieback is secured to the retaining wall,

strength, small-diameter steel casing and/or

while the other end is anchored to a stable structure, such as a back-wall or

threaded bars.

anchored into earth with sufficient resistance (grouted bond length). A tiedown is the same kind of anchor but installed vertically or nearly vertically.

Single-Corrosion Protection (SCP) Anchor A single layer of corrosion protection preventing the onset of corrosion during

Dextra’s trademark promoting versatile Steel & FRP ground engineering solutions. Fully threaded bars are the core components of our systems.

the designed life.

Double-Corrosion Protection (DCP) Anchor

Dextra’s trademark promoting unique FRP

Two protective barriers preventing the onset of corrosion during the designed life. Typical

/ FRP systems guarantee high performances

barriers include grout, a corrugated plastic duct, grease or epoxy coating.

for the most stringent of requirements.

| DEXTRA | G r o u n d E n g i n e e r i n g

solutions developed by Dextra. Our hybrid steel

Ground Anchor Retaining wall

Excavation

Fre

e le

Retaining walls for excavations are vertical structures that only allow limited deflection. Typically, pre-stressed active anchors are preferred.

ngt

len

gth

High strength tendons anchored to the retaining wall on one end and to the ground on the other end through a bulb of pressure injected grout named â&#x20AC;&#x2DC;bond lengthâ&#x20AC;&#x2122;.

Pages 12-13

Wire mesh + shotcrete

Slope Stabilization On soil-covered slopes, soil is constantly moving downslope due to gravity, therefore larger displacement have to be considered.

len

gth

Typically passive anchors are preferred. High strength tendons are fully grouted from the face of the slope into the stable ground.

Page 14-15

Rock-Bolt

Micropile

Tunneling & Mining

Foundations

Page 16-23

Page 24-25

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Applications

Material Specifications

STEEL Material • Continuous high-tensile hot-rolled threaded bars. • Modulus of Elasticity: 205 GPa (205 kN/mm²). • Available with either left-hand or right-hand threads. • Epocy coating for corrosion protection available upon request.

Benefits of fully threaded bars • Continuous thread increases the bonding with surrounding environment. • Coarse thread and hard bar surface making it robust and less susceptible to damages. • Length adjustment of fully threaded steel anchors is possible by cutting. Reconnection is possible at any point with couplers.

• High performance grades are available which allow the tendons and bore holes to be of a smaller diameter.

Steel specifications

Tendon Bar Nominal diameter (mm)

Crosssection area (mm²)

Linear weight (kg/m)

491

Grade 555/700*

Grade 830/1030

Grade 930/1080

Yield load (kN)

Ultimate load (kN)

Yield load (kN)

Ultimate load (kN)

Yield load (kN)

Ultimate load (kN)

4.10

273

344

408

506

457

530

804

6.65

446

563

667

828

748

868

1,019

8.41

566

713

856

1,050

948

1,105

1,257

10.34

698

880

1,043

1,295

1,169

1,358

1,963

16.28

1,089

1,374

1,629

2,022

1,826

2,120

63.5*

3,167

26.20

1,758

2,217

| DEXTRA | G r o u n d E n g i n e e r i n g

* Grade and diameter subject to minimum order quantities

Benefits of Fiber Reinforced Polymers (FRP) The anisotropic characteristic of FRP ensures that it can easily be cut by common excavation and piling equipment, as well as Tunnel Boring Machines (TBM). FRP solutions are the best alternative to removable CUT - ABILITY

CUT - ABILITY

CORROSION anchors place. LIGHTin WEIGHT FREEas they can be left

Suitable for permanent and temporary applications. In both cases it alleviates all concerns about corrosion: FRP profiles are available in formulations resistant to acidic and alkali environments. CUT - ABILITY CUT - ABILITY

CUT - ABILITY

CORROSION FREE

CUT - ABILITY

CORROSION FREE

LIGHT WEIGHT

CORROSION FREE

LIGHT WEIGHT

A clear advantage of FRP bars is the strength-to-weight ratio: eight times higher than steel. Indeed FRP profiles are twice stronger than

CORROSION FREE

LIGHT WEIGHT

steel in tensile for only 25% of its weight

CUT - ABILITY

FRP specifications

CUT - ABILITY

Diameters range LIGHT WEIGHT

CORROSION FREE

CUT - ABILITY

LIGHT WEIGHT

20 mm to 70 mm

19 mm to 41 mm

Ultimate Tensile Strength

Up to 1,000 MPa

Modulus of Elasticity (MoE)

Up to 50 GPa

Up to 60 GPa

System Performance

Standard accessories: 50% of the bar tensile strength

High performance accessories: 80% to 100% of the bar tensile strength

Fully threaded (rope thread)

Deformation by helical wrap + sand coating

CORROSION FREE

LIGHT WEIGHT

CUT - ABILITY

FRP

Up to 1,000 CORROSION MPa FREE

CUT - ABILITY

LIGHT WEIGHT

Bar Profile

w w w. d e x t r a g r o u p . c o m | DEXTRA | 9

GROUND ANCHORS

10 | DEXTRA | G r o u n d E n g i n e e r i n g

Identify the right anchor for your excavation & slope stabilization Service Life < 2 years (temporary*)

Service Life > 2 years (permanent*) > 2 years (permanent*)

Need to be removed or cut at a later stage Yes

FRP

Corrosive Environment

Moderately

Highly

Single Corrosion Protection

Double Corrosion Protection

FRP

GEOTEC Active Steel Anchor SCP

GEOTEC Active Steel Anchor DCP

ASTEC Active Anchor TB1/2

page 12

page 13

ASTEC Active Anchor TB3 page 13

Excavation (active anchoring)

ASTEC Soil Nail (T)

GEOTEC Passive Steel Anchor SCP

GEOTEC Passive Steel Anchor DCP

ASTEC Soil Nail (P)

page 14

page 15

Slope stabilization (passive anchoring) System based on FRP bars System based on fully-threaded steel bars

* Temporary and permanent applications are defined as per BS EN 1537:2013 w w w. d e x t r a g r o u p . c o m | DEXTRA | 11

Selection

Active Anchor

Active Anchor (Steel)

Codes & Standards

• Steel Active Anchors are the prefered solution for excavation works where post-tensioning is required. • Suitable for any temporary or permanent work as long as tendons do not encroach onto neighboring

• • •

BS EN 1997 (Eurocode 7) BS EN 1537 BS 8081

plots and do not need to be cut or extracted at a later stage.

• Wide range based on high-tensile fully threaded bars available in 6 diameters up to 63.5mm (see page 8). Higher grades may be prefered to ease handling and reduce the bored hole diameter.

• Corrosion protection accessories (SCP/DCP) are part of the system and can be supplied by Dextra.

Single Corrosion Protection (SCP) SCP is achieved by 1 layer of grout all along the whole length of the system

Free length

• Bonded length protection is achieved thanks to the fully threaded bar ribs together with a single layer of grout between the bar and the

Bond length

Smooth sheating

bored hole.

No internal grouting

• Unbonded length protection is achieved by

Grout

covering the fully threaded bar with a smooth

Centralizer

HDPE sheating.

Double Corrosion Protection (DCP) DCP is achieved by 2 layers of grout all along the whole length of the system. Free length

• Bonded length protection is achieved thanks to the dual grout layers separated by a corrugated HDPE sheating.

• Unbonded length protection is guaranteed

Steel cap filled with grease

Heatshrink joint

by the use of smooth HDPE pipe above the

External centralizer

corrugated HDPE sheating.

Corrugated HDPE pipe

• Steel cap and Plastic cap protect respectively the head and the end of the system. 12 | DEXTRA | G r o u n d E n g i n e e r i n g

Bond length

Smooth sheating

Stressing tail Retaining wall

End cap

Active Anchor (FRP)

Doha, Qatar

Codes & Standards • • • • •

ASTEC Active Anchors (AAA) is an unmatched hybrid GFRP/Steel system, designed as a post-tension anchoring solution for the geotechnical field. For tensioning, a patented connector system makes the interface between a high performance FRP bars and a standard PT strand.

ACI 440-4R-04 BS EN 1997 (Eurocode 7) BS EN 1537 BS 8081 ISO 6934-4

For temporary applications, the cut-able nature of ASTEC Active Anchors removes all needs for the systems to be removed from ground. No removal cost, no additional planning needed.

Key Numbers ASTEC Active Anchor is composed of multiple tendons which are assembled to provide high mechanical performance system which:

• Constitutes a geotechnical anchor for temporary and permanent usage that are then left in the ground and that won’t present an obstacle to any future construction projects as they can be easily cut through.

Numbers of tendons

From 1 to 14

Ultimate loads

250 to 3,500 kN

MoE

50 GPa

• Allows easy and fast future extirpation by common TBM and Pile Boring machines due to its anisotropic fiber characteristics.

• Does not require any additional periodic monitoring and maintenance. • Nullifies need for extra corrosion protection requirements. • Minimizes weight to ease handling & installation. PT Stand

Head block CUT - ABILITY

with HDPE-shealth protection 1

CUT - ABILITY

2 1

Free

lengt

Bearing plate Swaged sleeve

Threaded stud

Bond breaker Splicing system

Bond CUT - ABILITY

lengt

CUT - ABILITY

Spacer

1/ PT strand to GFRP rebar

GFRP rebar

2/ GFRP rebar to GFRP rebar

Stressing tail Retaining wall

CUT - ABILITY

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Passive Anchor

Soil Nail (Steel)

Codes & Standards

• Steel Soil-Nails, also called Passive Anchors, are the prefered solution for slope stabilization. The

• • •

system is bonded all along the whole tendon length. The head of the system will usually be covered by a wire mesh and shotcrete layer after installation.

FHWA-IF-03-017 FHWA-SA-96-069 HK GEOGUIDE 7

• Suitable for any temporary or permanent work as long as tendons do not encroach onto neighboring plots and do not need to be cut or extracted at a later stage.

• Wide range based on fully threaded bars available in 3 different grades and 6 diameters up to 63.5mm (see page 8). Higher grades may be prefered to ease handling and reduce bored hole diameter.

• Corrosion protection accessories (SCP / DCP) are fully part of the system and can be supplied by Dextra.

Single Corrosion Protection (SCP)

SCP applications

SCP is achieved by 1 layer of grout all along

Bond length

the whole length of the system

• Bonded length achieved with a single layer of grout between the bar and the bored hole Grout Centralizer

Double Corrosion Protection (DCP) DCP is achieved by 2 layers of grout all along the whole length of the system.

• Bonded length protection is achieved with

DCP applications

Steel cap filled with grease

Bond length

dual grout layers separated by a corrugated HDPE pipe

• Steel cap and Plastic cap protect respectively the head and the end of the system.

Corrugated pipe Internal centralizer External centralizer End cap

14 | DEXTRA | G r o u n d E n g i n e e r i n g

Soil Nail (FRP)

Codes & Standards • • • • •

ASTEC Soil-Nail is a non-corrosive passive anchoring system used for rock and soil stabilization. It is suitable for both temporary and permanent ground consolidation. The anisotropic characteristic of the FRP ensures that ASTEC Soil-Nail can easily be cut by

ACI 440-4R-04 FHWA-IF-03-017 FHWA-SA-96-069 HK GEOGUIDE 7 ISO 6934-4

common tunnel and pile boring machines. The unmatched connector allows installation of any length while allowing the system to develop the full strength of the rebar.

GFRP Bar

System

Product Reference

Diameter (mm)

Ultimate Tensile load (kN)

ASTEC SN50T-19

250

ASTEC SN50T-25

320

ASTEC SN50T-32

500

ASTEC SN50T-41

770

• Full Mechanical performace continuity . • Cut-able = Faster excavation + No removal cost. • Light- weight = Easy handling. • Integrated corrosion resistance. CUT - ABILITY

CUT - ABILITY

CUT - ABILIT

CUT - ABILITY

CUT - ABILIT

CUT - ABILITY

CUT - ABILIT

Steel stud Steel nut Bond length

Steel plate

Splicing system

Centralizer GFRP rebar Head and coupling system both developing the full strength CUT of the bar - ABILITY

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ROCK BOLTS

16 | DEXTRA | G r o u n d E n g i n e e r i n g

Identify the right Rock-Bolt for your Tunneling & Mining

Roof & Wall Bolting

Soft Rock

Hard Rock

Temporary

Permanent

Temporary

Permanent

GEOTEC Steel Self-Drilling Rock-Bolt

ASTEC FRP Hollow Rock-Bolt

page 21

GEOTEC Steel Mechanical Bolt

GEOTEC Steel Expandable Friction Bolt

page 19

page 22

page 23

GEOTEC Steel Mechanical Combo Bolt page 22

Face Bolting & Further Excavation Cohesive Soil & Hard Rock

Non-Cohesive Soil

GEOTEC FRP Solid Rock-Bolt

GEOTEC FRP Hollow Rock-Bolt

GEOTEC FRP Self-Drilling Rock-Bolt

page 18

page 19

page 20

Steel product

FRP product w w w. d e x t r a g r o u p . c o m | DEXTRA | 1 7

Selection

FRP Rock-Bolt: Solid & Hollow

FRP Solid

Codes & Standards

GEOTEC FRP Solid Rock-Bolt can be installed with resin cartridges or forced into pre-grouted holes. The cut-ability of FRP makes it the ideal solutions for face bolting or any other tunneling/mining application where further excavation is required.

• • •

BS EN 1997-1 BS EN 1537 BS 7861-1

• Fully threaded profile for optimum mixing and bonding properties • Available with chamfer to facilitate resin mixing and prevent gloving • Light-weight = Easy handling and installation in the tunnel • Cut-ability = Faster excavation process • Corrosion resistance = No premature bolt failure due to corrosion

CUT - ABILITY

CUT - ABIL

Head set Nut Plate Solid rebar

Nominal Diameter

Tensile Strength

20 mm to 40 mm

MoE

700 Mpa to 1,000 Mpa

CUT - ABILITY

45 Gpa

CUT - ABIL

Bonding

GFRP Thread Grout

Diameter (mm)

GFRP Bars

GFRP Plate + Nut



18 | DEXTRA | G r o u n d E n g i n e e r i n g

Steel Plate + Nut

Steel Coupler

Section CUT - ABILITY



CUT - ABILITY

CUT - ABIL

 Solid rebar



Grout

FRP Hollow Nut

GEOTEC FRP Hollow Rock-Bolt are inserted into the hole and directly grouted through

Plate

its hollow core. The cut-ability of FRP makes it the ideal solutions for face bolting or any other tunneling/mining application where further excavation is required.

Hollow rebar

• 2 in 1 = Act as both, anchor rod and grouting pipe Bonding

• Light-weight = Easy handling and installation in the tunnel • Cut-ability = Faster excavation process

GFRP Thread

• Corrosion resistance = No premature bolt failure due to corrosion

Grout

Outside Diameter (mm)

GFRP Bars

GFRP Plate + Nut

Steel Plate + Nut

Steel Coupler



Section Grout

Hollow rebar

Grout

FRP Hollow Head set Nut

ASTEC FRP Hollow Rock-Bolt is a high performance solution, used in projects requiring the highest specifications:

Plate Hollow rebar

• Domed Plate & Nut = Suitable for installation on un-even surfaces • Cut-able = Faster excavation + No removal cost • High performance system = body & head fit meet the stringent requirements

Bonding

• Permanent = high resistance to acidic and alkaline environments

Sand Helical wrap Grout Section Grout

Hollow rebar

Nominal Diameter Product Reference

ASTEC HRB2-32

Minimum Hole Diameter

Body Anchorage Torsional Tensile Head Strength Load Tensile Load

Outside

Inside

≤34

≥480

≥200

Grout

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Head set

Self-Drilling Rock-Bolt (SDRB)

FRP SDRB

Codes & Standards • • •

Head set

BS EN 1997-1 BS EN 1537 BS 7861-1

Nut Plate CUT - ABILITY

CUT - ABILITY

GFRP hollow bar

Unit

Value

Inside Diameter CUT - ABILITY

mm CUT - ABILITY

15CUT - ABILITY

Drill-Bit Outside Diameter

Ultimate Load

250

Torque

N.m

200

Outside Diameter CUT - ABILITY

Steel coupler

CUT - ABILITY

3 in 1 concept: acts as a drilling rod, as well as an anchor bar and a grouting pipe.

Drilling bit

Product features

Benefits

•

• •

Crosscut for soft rock

•

20 | DEXTRA | G r o u n d E n g i n e e r i n g

Suitable for both permanent and temporary applications Optimum bonding and load transfer Splicing system (coupler) to adjust to custom lengths Standard sacrificial drill bits for every ground conditions

• • •

Flexible installation: core injection to suit all ground conditions Safety: Visual control of full encapsulation One step installation with sacrificial drill bits: drilling, placing, grouting No cased borehole allowing ground preservation

3 in 1 concept: acts as a drilling rod, as well as an anchor bar and a grouting pipe

Product features

Benefits

•

• • •

Suitable for both permanent and temporary applications. Optimum bonding and load transfer Splicing system to adjust to custom lengths. Standard sacrificial drill bits for every ground conditions.

• •

•

Flexible installation: core injection to suit all ground conditions. Safety: Visual control of full encapsulation. One step installation with sacrificial drill bits: drilling, placing, grouting. No cased bore hole allowing ground preservation.

Head set Nut Plate Steel hollow bar Rope thread (R)

Trapezoidal thread (T)

Corrosion Protection For temporary applications, the corrosion protection is achieved through encapsulation with grout. For permanent applications, epoxy coating is also available upon request.

Steel coupler

Technical Information Fully coarse threaded hollow bar

Outer Ø

Yield load

Ultimate load

(mm)

(kN)

150

200

R32N

230

280

R32S

280

360

R32SS

330

400

R38N

400

500

R51L

450

550

R51N

630

800

T30N

260

300

T40N

525

600

T40L

425

540

T76N

1,200

1,600

Product Reference

Thread Type

R25N

Drilling bit Crosscut for soft rock

Bolt bit for hard rock

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Steel SDRB

Mechanical Bolt

Mechanical Bolt GEOTEC Mechanical Bolt is inserted into the hole and anchored to the rock with the help of its expansion shell. The mechanical bonding is immediate and doesn’t require any grouting or resin.

• • •

Codes & Standards • • •

BS EN 1997-1 BS EN 1537 BS 7861-1

Immediate anchor joint support for faster excavation. No grouting or chemical needed. Different type of shell to adapt any kind of boring holes.

Available for boreholes 35 to 51 mm.

Combo Bolt GEOTEC Mechanical Combo Bolt is suitable for the most stringent requirements. A mechanical bolt combined with a corrugated pipe and a double grout layer all along tendon to provide both high bonding and protection against corrosion (similar to Double Corrosion Protection / DCP).

• • •

Fast installation for a high productivity Dual anchorage: punctual + full encapsulation. Suitable for corrosive environment Expansion Shell Close

22 | DEXTRA | G r o u n d E n g i n e e r i n g

Open

Product features

Benefits

• • • •

•

Available diameters: 26 mm and 36 mm. Minimum elongation 20%. Steel grade S355MC as per EN10149-2. Load capacity: DM120: 12 metric tons. DM160: 16 metric tons. DM240: 24 metric tons.

•

• • • • • • • •

Head set

High load-bearing capacity combined with excellent ductility elongation properties. The ductility elongation properties allow substantial rock movement without the bolt shearing. Immediate full length support for faster excavation. Simple and clear installation. Adjusts to borehole irregularities. Reliable installation quality. Flexible to variations in drill hole diameter. Versatile bolting solution for variable ground conditions. No grouting or chemical needed. Manual or mechanical installation at choice.

Technical Information

Injection bushing Plate

Product type

Description DM120

DM160

DM240

Expandable tube

Variable length up to

12,000 mm

Friction bolt section view

Wall thickness

2 mm

3 mm

Bolt diameter

26 mm

36 mm

Primary tube

41 mm

54 mm

Hole diameter range

32-40 mm

45-53mm

45-53 mm

Properly hole diameter

36-39 mm

48-52 mm

Ultimate load

120 kN

160 kN

240 kN

Tube elongation

≥ 20%

Typical elongation

30%

Lofted plate

150x150x6

200x200x6

200x200x8

Lofted plate hole

30 mm

40 mm

Weight

2 kg/m

2.80 kg/m

3.80 kg/m

Before expansion

After expansion

End bushing

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Expandable Friction Bolt

MICRO PILES

24 | DEXTRA | G r o u n d E n g i n e e r i n g

Selection

• • •

Identify the right micropile for your foundations

Tension

Compression

Single bar

Multiple bars

BS 5950 BS EN 1997 (EC7) (Eurocode 7) BS EN 14199

Compression tension

Micropile Micropiles are structural elements used to transmit an applied tension or compression load into soil or rock. As passive anchors, they

not

require

post-tensioning.

Suitable for both compression and tension applications

Single Corrosion Protection

Double Corrosion Protection

thanks

customizable

head

accessories. For long tendons, couplers may be used to splice threaded bar segments together. Wide

range

based

fully

threaded

bars available in 3 different grades and 6 diameters up to 63.5mm (see page 8). Higher grades may be prefered to ease handling and reduce bored hole diameter. Corrosion protection accessories (SCP / DCP) are fully part of the system and supplied by Dextra. Alternatively, Dextra can also deliver

the

DCP

assemblies

pre-grouted.

Multi-bar systems available on request.

w w w. d e x t r a g r o u p . c o m | DEXTRA | 2 5

Codes & Standards

WORLWIDE References

Major Stations - Musheireb Doha, Qatar, 2014 Client: Samsung OHL QBC - JV

26 | DEXTRA | G r o u n d E n g i n e e r i n g

Al-Shahad Tower - West Bay Doha, Qatar, 2015 Client: Navayuga

Al Sadd C-Ring Station Doha, Qatar, 2016 Client: ALYSJ Golden Line

Grand Paris Express â&#x20AC;&#x201C; Bagneux M4-15 Paris, France, 2016 Client: Franki Foundations

MTRC - Contract XRL 823A Hong Kong, 2013 Client: Maeda

MRTC - Contract KTE 1001 Hong Kong, 2015 Client: Nishimatsu Construction

w w w. d e x t r a g r o u p . c o m | DEXTRA | 2 7

Hong Kong

Bangkok

Mumbai

São Paulo

Panama

Dubai

LosAngeles Angeles Los

Paris

Guangzhou

Contact

Commercial presence in more than 55 countries.

EUROPE Dextra Europe SARL. Tel: (33) 1 45 53 70 82 Fax: (33) 1 47 04 28 97 E-mail: europe@dextragroup.com

CHINA Dextra Building Products (Guangdong) Co., Ltd. Tel: (86) 20 2261 9901 Fax: (86) 20 2261 9902 E-mail: china@dextragroup.com

MIDDLE EAST Dextra Middle-East FZE Tel: (971) 4886 5620 Fax: (971) 4886 5621 E-mail: middleeast@dextragroup.com

HONG KONG Dextra Paciﬁc Ltd. Tel: (852) 2845 7766 / 2511 8236 Fax: (852) 2586 1656 / 2519 0852 E-mail: dplbuilding@dextragroup.com

INDIA Dextra India Pvt. Ltd. Tel: (91) 22 2838 6294 / 22 2839 2694 Fax: (91) 22 2839 2674 E-mail: india@dextragroup.com

www.dextragroup.com

NORTH AMERICA Dextra America Inc. Tel: (1) 805 915 4734 / 818 261 5166 E-mail: america@dextragroup.com

LATIN AMERICA Dextra Latam Tel: (507) 6454 8100 / 831 1442 E-mail: latam@dextragroup.com

SOUTH AMERICA Dextra do Brasil Tel: (55) 11 5505 2475 / 11 5505 2477 E-mail: brasil@dextragroup.com

Ground Engineering - February 2017 Digital - VDH + PS

HEADQUARTERS THAILAND Dextra Manufacturing Co., Ltd. Tel: (66) 2 021 3800 Fax: (66) 2 328 0374 E-mail: thailand@dextragroup.com