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KOSTEEL Co., Ltd.       ​

4F Haustory 122, Sagajeong-ro, Dongdaemun-gu, Seoul, 02531, Korea

+82) 2-2106-0135    

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ⓒ KOSTEEL

application

Tunnels are essential to modern infrastructure. NATM(New Austrian Tunneling Method) and TBM(Tunnel Boring Machine) are most widely used methods to drill a tunnel. Both methods definitely need to be stabilized with reinforced concrete on the drilled surface.

 

BUNDREX offers a wide range of products that can be ideally used for NATM and TBM method depending on tunnel conditions .

steel fiber reinforced sprayed concrete

NATM needs to spray concrete where necessary and the concrete is reinforced with mesh or fibers to support ground sufficiently most of the time.

As fibers, especially steel fibers, show better concrete performance and also safer and easier work, fibers are regarded as a better solution for reinforcement than mesh.

BUNDREX have supplied 450km long 500 tunnels (more than 200,000MT) with our steel fibers for sprayed concrete of NATM tunnels, which proves BUNDREX is the best solution for sprayed concrete.

Advantage of Steel fiber Reinforced Sprayed Concrete (vs. Mesh)

Mesh Reinforcement Sprayed Concrete

Steel Fiber Reinforced Sprayed Concrete

Difficult to install wire mesh in case of back break from excavation; decreased reinforcement effects.

Increased reinforcement effects with wall of even thickness

on a rugged surface.

Decreased adhesion, layer splitting, hollowing-out

due to vibration on wire mesh when placing shotcrete.

Increased tensile strength, bending strength, shear strength of concrete; no hollowing-out; reduction of wall thickness(20%).

High frequency of cracking in shotcrete

and decreased reinforcement effects in case of cracking.

High resistance to cracking;

increase in toughness (residual strength) after cracking.

Shotcrete reinforcement needed right after excavation 

due to risk of cave-in disasters;

decreased reinforcement effects due to delay of reinforcement.

Shotcrete construction possible right after excavation;

drop in risk of cave in disasters;

rise in reinforcement effects and safety of permanent structures.

Low constructability and complex work process.

Streamlined work process; rise in quality and safety.

Increased construction costs due to longer working hours.

Reduced working hours and construction costs.

Product Line-up for Sprayed Concrete

Product Code

D(mm)

L(mm)

L/D

KF 60/30 CH

 

steel fiber reinforced sprayed concrete

NATM needs to spray concrete where necessary and the concrete is reinforced with mesh or fibers to support ground sufficiently most of the time.

As fibers, especially steel fibers, show better concrete performance and also safer and easier work, fibers are regarded as a better solution for reinforcement than mesh.

BUNDREX have supplied 450km long 500 tunnels (more than 200,000MT) with our steel fibers for sprayed concrete of NATM tunnels, which proves BUNDREX is the best solution for sprayed concrete.

Advantage of Steel fiber Reinforced Sprayed Concrete (vs. Mesh)

Mesh Reinforcement Sprayed Concrete

Steel Fiber Reinforced Sprayed Concrete

Difficult to install wire mesh in case of back break from excavation; decreased reinforcement effects.

Increased reinforcement effects with wall of even thickness

on a rugged surface.

Decreased adhesion, layer splitting, hollowing-out

due to vibration on wire mesh when placing shotcrete.

Increased tensile strength, bending strength, shear strength of concrete; no hollowing-out; reduction of wall thickness(20%).

High frequency of cracking in shotcrete

and decreased reinforcement effects in case of cracking.

High resistance to cracking;

increase in toughness (residual strength) after cracking.

Shotcrete reinforcement needed right after excavation 

due to risk of cave-in disasters;

decreased reinforcement effects due to delay of reinforcement.

Shotcrete construction possible right after excavation;

drop in risk of cave in disasters;

rise in reinforcement effects and safety of permanent structures.

Low constructability and complex work process.

Streamlined work process; rise in quality and safety.

Increased construction costs due to longer working hours.

Reduced working hours and construction costs.

Product Line-up for Sprayed Concrete

Remarks

Remarks

SFRC precast segment for tbm

Shield TBM method is widely used to drill a tunnel where it is under sea, it has weak ground or blasting is not possible.

The method is to install precast segment lining after excavating ground with TBM (Tunnel Boring Machine).

In the past, rebar was mainly used for reinforcement of precast segment but as the performance of steel fiber is enhanced a lot recently, rebar is being replaced with steel fiber.

BUNDREX offers steel fibers that fits well to precast segment.

SFRC Precast Segment Manufacturing  Process

The production of segment is a lot simpler because rebar cage process is not required.

Productivity is improved and production cost is reduced.

Advantage of SFRC Precast Segment for TBM

Improvement of productivity

Reduces time, space and labor used for installing rebar during segment precast manufacturing.

Improvement of durability

Increases crack control and breakage joints between segments caused by jack thrust through the effect of 3-dimensional dispersion of steel fiber​.

Improvement of cost-efficiency

Reduces cost of steel material for reinforcement and labor cost

Reduces maintenance cost by better durability.

Product Line-up for Precast Segment

Product Line-up for Precast Segment

1,100 ~ 1,200

is the best alternative for a precast segment under high load bearing condition.

The production of segment is a lot simpler because rebar cage process is not required.

Productivity is improved and production cost is reduced.

Product Code

D(mm)

L(mm)

L/D

T/S (MPa)

Remarks

 

sfeed-pro for segmental lining

SFEED-PRO, developed by R&D team of BUNDREX reflecting state of the art construction design standards of EU & US, provides the best structural design solution to our customers in order to realize the superior performance of our steel fiber.

SFEED-PRO-SEG is a program to design segmental lining for tunnel. 

BUNDREX keep updating the program reflecting the state of the art technology to satisfy customers' needs.

 

  • Design standards: RILEM, ITA, ACI 544

  • Unit: SI

  • SFRC performance parameter: Re3, CMOD value