High-Energy Absorption
Rockfall Protection Construction

TOKYO ROPE MFG. CO., LTD.

Curtain Net method can absorb rockfall energy
with the whole wire net, which provides
high-energy-absorption performance.
With the Curtain Net, struts and suspension ropes are not installed on the slope intended to draw
falling rocks, but unique robust struts are installed on both stable sides less prone to rockfall and are
secured by suspension ropes and stay ropes. With this arrangement, falling rocks do not strikedirectly on the struts or suspension ropes, but the rockfall energy is absorbed only by the curtain as
it is an elastic body. Thus, it is a high-energy absorbing, rockfall protection construction method.

12

Features
Tough and excellent in absorbing rockfall energy

Main rope

Reinforcing rope

The horizontal ropes along the top of the curtain and strut suspension ropes are stronger and more
flexible than the wire ropes used in conventional pocket-type rock nets. Besides, the vertical andhorizontal ropes (both main and reinforcing ropes) are placed densely, so that falling rocks of large
size are received integrally by both the rope and net members together, rather than by the net
alone.
The larger deal load of the curtain means a greater difference in energy before and after collision,
which results in substantial increase in the capacity to absorb rockfall energy.

Struts can be placed wider apart
Unlike the conventional pocket-type rock net, strut-to-strut intervals can be increased.
Consequently, struts can be installed on stable locations, avoiding dangerous slope and swamp
areas susceptible to rockfall and unstable cliffs. This arrangement prevents falling rocks from striking
directly on the struts and suspension ropes. On undulating slopes, the undulation can be utilized,that is, anchors can be installed directly in stable ground to extend the top horizontal top ropes toinstall the curtain.

Rocks falling from high elevations can be received securely
The struts supporting the curtain are tall at 2.5 to 8.0 meters and form a large opening in the upper
pocket, which reliably accommodates rocks bounding down from high elevations.

3Horizontal rope

StrutStrut

Prone to less damage and easy in maintenanceThe curtain that receives falling rocks is less prone to damage because
its wire ropes and nets are composed of strong and flexible materials.
In addition, falling rocks are guided more desirably to the foot ofslope than in the pocket-type rock net, so that accumulated rocks canbe removed more easily.

High corrosion resistance and durability
High durability versions provide an expected service life of more than
50 years in mountainous areas.
Excellent corrosion resistance and durability result from thegalvanization on all members. Wires, such as those used in wire netsand wire ropes, which are low in plating coating weight, are appliedwith zinc-aluminum alloy plating to improve corrosion resistance anddurability.

It is not desirable that important facilities built to prevent rockfall
accidents loose their function in short times due to corrosive
deterioration of any particular component member. Based on thisidea, standard plating specifications assure at least 50 years ofcorrosion resistance in mountainous areas, which are typical locations
for such facilities.

Environmentally compatible (Toff-coated) version“Toff-coated products” are offered as environmentally compatible versions, which are applied withmodified saturated polyester resin coating on the plated surface. The coating film of these products
provides resistance to peeling, resistance to scratches, and high adhesiveness, which together serve
to prevent salt damage. The Toff-coated version also features acid/alkali resistance that has not beenachieved by metal-based rust prevention. Furthermore, the film strength and elongation provide
high reliability for the coating of deformation-susceptible products such as wire rope and wire net.
When the Toff-coating is applied to winding grips, the power of fixing with the rope remains
conformant to the standard value.

4

Example of construction

Curtain Net

Curtain Net

5The construction site: Tokushima Prefecture, Japan (CN-5.0)

The construction site: Chiba Prefecture, Japan (CN-5.0)

Curtain Net

The construction site: Chiba Prefecture, Japan (CN-4.0)

Curtain Net SuperThe construction site: Hiroshima Prefecture, Japan (CN-S)

6

CURTAIN NET
The models are CN-5.0ZA and CN-4.0ZA for rhombus wire nets of 5.0φ and 4φ wires, respectively, platedwith zinc aluminum alloy, and CN-5.0G and CN-4.0G for rhombus wire nets of galvanized element wires.
Further, Model TF refers to nets applied with Toff-coating over the galvanized surface.
When a net of Model 5.0 uses top horizontal ropes and strut suspension ropes of 7x7 30φ, it is referred toas Model CN-5.0ZA (G, TG)-30.

Model CN-5.0ZA (G, TF) Model CN-4.0.0ZA (G, TF)
Model

Wire net
Top horizontal rope
Vertical/horizontal ropes
Vertical/horizontal reinforcing ropes
CN strut (with ladder)
Strut suspension rope
Strut side stay rope
Anchor fitting
TR Cement Jaw Anchor
FR anchor
Saddle (for FR anchor)Root anchor
Turnbuckle J&E
Turnbuckle E&E for Strut connection
Wire grip
ThimbleWinding grip
Suspension fitting
Cross grip
Coupling coil

Model CN-5.0ZA (G, TF)

Model CN-4.0ZA (G, TF)

5.0φ×50×50
7×7 24φ
3×7 18φ
3×7 14φ
H‐200×200×8×12, 2‐M33×1200
7×7 24φ
3×7 18φ25ｔ×450×450, 4‐M30×1200
M33×1200
FRC190 7×7 30φ 6.0m
16×600×1000
114.3φ×4.5×1800
1・1/2×419（38φ）
M24×350
M24×350
F24-25
A‐28For 18φ
For 14φ
For 24φ
4.5ｔ×60×75
4.0φ×70×300

4.0φ×50×50
7×7 20φ
3×7 16φ
3×7 12φH‐175×175×7.5×11, 2‐M30×1200
7×7 20φ
3×7 16φ25ｔ×450×450, 4‐M27×1200
M33×1200
FRC130 7×7 30φ 5.0m
16×600×1000
114.3φ×4.5×1800
1・1/2×419（38φ）
M24×350
M24×350
F20-22
A‐22For 16φ
For 12φFor 20φ4.5t×60×75 and 3t×60×60
4.0φ×70×300

Note: All parts are galvanized. For standard versions (ZA), the wire nets, wire ropes, and winding grips, which are low in plating coating weight, are plated with a highly durable alloyof zinc and 10% aluminum. For TF versions, members with a plating coating weight of 550 g/m2 or more (HDZ-55) are applied with powder coating baking.

Selection Chart
1000

1000

Model CN-5.0

800

Hn=24m L=18m

700

Hn=18m L=18m

600

Hn=12m L=18m

500
400
300
200
10000

Hn=24m L=18m

Hn=18m L=18m
5.0

10.0

15.0

Hn = curtain height; L = curtain length7

Hn=24m L=18m

800
700

Hn=18m L=18m

600

Hn=12m L=18m

500
400
300
2000

Hn=12m L=18m

Rockfall load W (kN)

Model CN-5.0-30

900

Total absorption energy ET (kJ)

Total absorption energy ET

900

Model CN-4.005.010.015.0

Rockfall load W (kN)

20.0

25.0

Hn = curtain height; L = curtain lengthModel CN-5.0ZA (G, TF)-30
Model

Model CN-5.0ZA (G, TF)-30
Wire net
Top horizontal rope
Vertical/horizontal ropes
Vertical/horizontal reinforcing ropes
CN strut (with ladder)
Strut suspension rope
Strut side stay rope
Anchor fitting
TR Cement Jaw Anchor
FR anchor
Saddle (for FR anchor)
Root anchor
Rigging screw
Turnbuckle J&E
Turnbuckle E&E for Strut connection
Wire grip
ThimbleWinding grip
Suspension fitting
Cross grip
Coupling coil

5.0φ×50×50
7×7 30φ
3×7 18φ
3×7 14φ
H‐200×200×8×12, 2‐M33×1200
7×7 30φ
3×7 18φ25ｔ×450×450, 4‐M33×1350
M33×1200
FRC290 7×7 30φ 8.5m
16×６００×1000
114.3φ×4.5×1800
Nominal 36
M24×350
M24×350F30-32
A‐34
For 18φ
For 14φ
For 30φ4.5ｔ×60×75
4.0φ×70×300

Note: All parts are galvanized. For standard versions (ZA), the wire nets, wire ropes, and winding grips, which are low in plating coating weight, are plated with a highly durable alloyof zinc and 10% aluminum. For TF versions, members with a plating coating weight of 550 g/m2 or more (HDZ-55) are applied with powder coating baking.

Full scale weight impact tests
Model CN-5.0ZA

The test confirms that a descending horn-shaped concrete
plumb bob(10kN) from the upper chute with revolving
movement (plumb bob energy 389kJ) collided with theCurtain net construction and it catches the plumb bob
without being penetrated.

123After the impact

8CURTAIN NETStructure of Curtain Net

1000

6000

6000

Hn

1000

6000

f+500

CN-5.0Standard structuraldevelopment diagram

1000

1000
3000

3000

3000 3000

3000

3000
L

3000

3000

3000

3000

3000

3000
L21000

3000

Parts listSymbol

Part name

SymbolAnchor fitting
TR Cement Jaw Anchor
Turnbuckle
Wire grip
Winding grip
Suspension fitting
Cross grip
Coupling coil

SymbolFR anchor FRC-190

1000

Part name

Wire net
Top horizontal rope
Vertical rope
Horizontal rope
Vertical reinforcing rope
Horizontal reinforcing rope
Strut
Strut suspension rope
Strut side stay rope

6000150

Top horizontal rope/
suspension rope

60

50000
4500
4000

Anchor fitting

Turnbuckle J&E 1・1/2（38φ）×419

SaddleWire grip F24-25 Thimble A-28

Cast-in anchor

Suspension rope 7×7 24φ

f+500

Strut

Top horizontal rope
7×7 24φSpacerRoot anchor
Root anchor
114.3φ×4.5-1800

Strut side stay rope
3×7 18φ

GroutFR anchor 7×7 30φ

Thimble A-20
Wire grip F-18

Hn2PL-6×200×300

TR Cement Jaw Anchor
M33×1200

18

Horizontal rope 3×7 18φ

00

Winding grip
For 18φ - 1350

9Guide rope 7×19 18φ

StrutPL-25t×270×450ｈ

Strut height2.5200

300

450ｈ
（m）
3.0
3.5

Ladder φ19

4.0
4.5
5.0

H-200×200×8×125.5

270200

6.0
6.5
7.0
7.5

TR Cement Anchor, complete: with 2 nuts;
and washers with reinforcing pipe2-M33×1200

8.0

Underground cast-in anchor for strut foundation

Turnbuckle

PL-19t×950×950
2000

J&E 1・1/2（38φ）
×419
38950

950419J&E M24×350
24114.3φ×4.5t

350

Suspension fitting
Top horizontal rope 7×7 24φ

150

Anchor fitting
450246300

Verticalreinforcing rope

Vertical rope

Verticalreinforcing rope

Vertical rope

450

300

for 24φ 2PL-12t×150×246

300

25 200TR Cement Jaw Anchor

1200

TR Cement Anchor,
complete: with 2 nuts;
and washers withreinforcing pipe
M30×1200

M331200

Note: Separate specifications apply if snow load is taken into consideration.

10

CURTAIN NET SUPER
These models comprise a rhombus wire net of 5.0φ element wires plated with a zinc-aluminum alloy. Twomodels are the standard: Model CNS-S (ZA) with two top horizontal ropes of 7x7 ZA/0 30φ, and Model
CNS-M (ZA) with horizontal ropes of 7x7 ZA/0 24φ. In addition, the model using wire nets, wire ropes,
winding grips, and coupling coils, all plated with a zinc-aluminum alloy, is Model G and the one appliedwith Toff-coating is Model TF.

Model CNS-S (ZA, G, TF)
Model

Model CNS-S (ZA, G, TF)
5.0φ×50×50
7×7 30φ
3×7 18φ
3×7 14φ
H‐250×250×9×14, 4‐M33×1200
7×7 30φ
3×7 18φ
for 30φ 25×450×450, 4‐M33×1350
38φ×1200
FRC‐290 7×7 30φ 8.5m
16×600×1000
114.3φ×4.5×1800
Nominal 36
M24×350
3×7 18φF30‐32
A‐34
for 18φ
for 14φfor 2×30φ
4.5ｔ×60×75
4.0φ×70×300
4.0φ×100×300

Wire net
Top horizontal rope
Vertical/horizontal ropes
Vertical/horizontal reinforcing ropes
CNS strut (with ladder)
Strut suspension rope
Strut side stay rope
Anchor fitting
TR E Anchor
FR anchor
Saddle (for FR anchor)
Root anchor
Rigging screw
Turnbuckle J&E
Joint rope, with both ends worked for Toyolock
Wire grip
ThimbleWinding grip
Suspension fitting
Cross grip
Coupling coil
Coupling coil (for top rope)

Note: All parts are galvanized. For standard versions (ZA), the wire nets, wire ropes, and winding grips, which are low in plating coating weight, are plated with a highly durable alloyof zinc and 10% aluminum. For TF versions, members with a plating coating weight of 550 g/m2 or more (HDZ-55) are applied with powder coating baking.

Selection Chart
1500

Model CNS-S

1500

Hn=24m L=39m

1200

Hn=24m L=30m

Hn=12m L=39m
Hn=24m L=24m
Hn=12m L=30m
00152025

Hn=12m L=39m
Hn=24m L=24m

600

Hn=12m L=30m
3035

Hn = curtain height; L = curtain length11

Hn=24m L=30m

900

Hn=12m L=24m

Rockfall load W (kN)

Model CNS-M（Hn=24m）

Hn=24m L=39m

1200

900

600

Model CNS-M（Hn=12m）（Hn=24m）

Total absorption energy ET (kJ)

（Hn=12m）

Total absorption energy (kJ)

1800

Model CNS-S

0015

Hn=12m L=24m
2025

Rockfall load W (kN)3035

Hn = curtain height; L = curtain lengthModel CNS-M (ZA, G, TF)
Model

Model CNS-M (ZA, G, TF)
5.0φ×50×50
7×7 30φ
3×7 18φ
7×7 24φ
3×7 14φ
H‐250×250×9×14, 4‐M33×1200
7×7 30φ
3×7 18φ
for 30φ 25×450×450, 4‐M33×1350
25×450×450, 4‐M30×1200
38φ×1200
FRC‐290 7×7 30φ 8.5m
16×600×1000
FRC‐190 7×7 30φ 6.0m
16×600×1000
114.3φ×4.5×1800
Nominal 36
M24×350
3×7 18φF30‐32
A‐34
F24‐25
A‐28
for 18φ
for 14φfor 2×30φ
4.5ｔ×60×75
4.0φ×70×3004.0φ×100×300

Wire net
Top horizontal rope
Vertical rope
Horizontal rope
Vertical/horizontal reinforcing ropes
CNS strut (with ladder)
Strut suspension rope
Strut side stay rope
Anchor fitting (for suspension/top horizontal ropes)
Anchor fitting (for horizontal rope)
TR E Anchor
FR anchor (for suspension/top horizontal ropes)
Saddle (for FR anchor)
FR anchor (for horizontal rope)
Saddle (for FR anchor)
Root anchor
Rigging screw
Turnbuckle J&E
Joint rope, with both ends worked for Toyolock
Wire grip (for suspension/top horizontal ropes)
Thimble (for suspension/top horizontal ropes)
Wire grip (for horizontal rope)
Thimble (for horizontal rope)
Winding grip
Suspension fitting
Cross grip
Coupling coil
Coupling coil (for top rope)

Note: All parts are galvanized. For standard versions (ZA), the wire nets, wire ropes, and winding grips, which are low in plating coating weight, are plated with a highly durable alloyof zinc and 10% aluminum. For TF versions, members with a plating coating weight of 550 g/m2 or more (HDZ-55) are applied with powder coating baking.

Full scale weight impact tests
Model CNS‐S

The test confirms that a descending horn-shaped concrete
plumb bob (20kN) from the upper chute with revolving
movement (plumb bob energy 803kJ) collided with theCurtain net construction and it catches the plumb bob
without being penetrated.

123After the impact

12

CURTAIN NET SUPER
Structure of Curtain Net Super

500

6000

6000

Hn500

6000

f+500

CNS-S
Standard structuraldevelopment diagram

500

500
3000

3000

3000

3000

3000

3000
L

3000 3000

3000

3000

3000

3000

3000

L2

2000

Parts listSymbol

Part nameAnchor fitting
TR E Anchor
Turnbuckle
Wire grip
Winding grip
Suspension fittingCross grip
Coupling coil

SymbolFR anchor FRC-290
1000

Part name

Wire net
Top horizontal rope
Vertical rope
Horizontal rope
Vertical reinforcing rope
Horizontal reinforcing rope
Strut
Strut suspension rope
Strut side stay rope

6000150500

Top horizontal rope/
suspension rope
Anchor fitting
Rigging screw, nominal 36
Wire grip F30-32 Thimble A-34

8500

7000
6500

SaddleCast-in anchor

GroutSuspension rope
FR anchor 7×7 30φ

StrutfSpacer
Top horizontal rope
7×7 30φ

Root anchor

Hn

Strut side stay rope
3×7 18φ

Thimble A-20

Root anchor
114.3φ×4.5-1800
2PL-6×200×300

Wire grip F-18

TR E Anchor
38φ×1200
Horizontal rope 3×7 18φ
1800

Winding grip for 18φ

13

Guide rope 7×19 18φ

StrutｈStrut height
1300
400 300 400
700250ｈ
（m）
2.5
3.0
3.5
4.0

Ladder φ19

4.5
5.0

2PL-25t×350×600

5.5
6.0

250

H-250×250×9×14

350

6.5
7.0
7.5

TR Cement Anchor, complete: with 2 nuts;
and washers with reinforcing pipe
4-M33×1200

8.0

Turnbuckle

Joining rope for strut connection
J&E M24×350

850

2456

Rigging screw, nominal 36

340

3×7 18φ

350

Thimble A-20620

Suspension fitting
Top horizontal rope 7×7 30φ150Anchor fitting

260

450

Verticalreinforcing rope

Vertical rope

Verticalreinforcing ropefor 2-30φ 2PL-12t×150×260

Vertical rope

450300300300200

TR E Anchor

TR Cement Anchor,
complete: with 2 nuts;
and washers withreinforcing pipe
M33×1350

1350

2538φ

120014

TOKYO ROPE MFG. CO., LTD.
TOKYO ROPE MFG. CO., LTD.
NIHONBASHI FRONT BLDG. 6-2 NIHONBASHI 3-CHOME CHUO-KU TOKYO 103-8306 JAPAN
Tel.: + 81 3 6366 7788, Fax: +81 3 3278 6870

The Representative office of Tokyo Rope MFG. CO.,LTD. in Moscow
22, Bolshaya Yakimanka str., Moscow, 119180, Russia
Tel.: + 7 495 645 04 03, Fax: +7 495 645 04 09

The Representative office of Tokyo Rope MFG. CO.,LTD. in Kazakhstan
Office No. VP-62,7th floor,Business center “Na Vodno-Zelyonom Bulvare”,
BLDG No. 12/1, D. Kunayev Street,Astana city, 010000, Republic of Kazakhstan
Tel.: + 7 7172 500 759, Fax:+ 7 7172 500 780
http://www.tokyorope.co.jp
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