TS-LV Snow Rake

Area of Application

A flexible-net snow rakes are static defense structures installed on steep slopes to prevent the initiation of avalanches. They are most often used for protecting urbanized areas and linear infrastructure such as roads, pipelines and other utility corridors that pass through mountainous terrain. Snow rakes are similar to larger snow nets but are more effective for snow depths up to 2.5 m.

Simple Installation

The net of the snow rake is installed on the upslope side of the fence but is in the same vertical plane of the post. This greatly simplifies installation. Upslope retention of the post head is provided by a single steel wire rope that is installed in the fall line to reduce the effects of drag.

Base Plate

The base plate is similar to that used for standard hinged rockfall catchment fences. It uses a tension anchor on the upslope side and a compression anchor on the downslope side. The lower bearing rope is led through a guide that secures its position while at the same time allowing deflection.

Post Head

The upper bearing rope is fixed to the post head using U-bolts. A deflection guide is provided to protect the bearing rope while it experiences large deflections during fully loaded conditions.

Adaptable to Topography

Due to the highly flexible nature of the Omega-Net, snow rakes and snow nets by Trumer are highly adaptable to difficult terrain. They can be installed at sites that would be impossible using more rigid materials.

Classification
ModelTS-LV Snow Rake
StyleHinged
Design Pressure
[kN/m2(lbf/ft2)]
up to 150
(3133)
Available Heights
[m (ft)]
up to 2.5
(8.2)
VerificationAnalytical
(site-to-site)
Primary Net
ModelOmega-Net 4.5/100Omega-Net 6.0/135
TypeSteel Wire CableSteel Wire Cable
Rope Diameter
[mm (inch)]
4.5
(0.18)
6.0
(0.24)
Rope Construction1 x 7 Spiral1 x 7 Spiral
Single Wire Diameter
[mm (inch)]
1.5
(0.06)
2.0
(0.08)
Corrosion ProtectionZnZn/ZnAl (Class A)
Mesh Size
[mm (inch)]
100 x 100
(3.9 x 3.9)
135 x 135
(5.3 x 5.3)
Unit Weight
[kg/m2(lb/ft2)]
2.7
(0.55)
3.6
(0.74)
Mesh Tensile Strength
calculated [kN/m (lbf/ft)]
154
(10,552)
246
(16,856)
Connection to Main RopesThreadedThreaded
Connection to Adjacent Panel1/4" Shackle5/16" Shackle
Omega-Net

The primary net material used in Trumer systems is called the Omega-Net. It is a steel cable net made from spiral rope that has thick individual wires to resist abrasion. The strands of rope are pre-bent into arcs resembling an omega shape and then woven together to make the net. This process yields an extremely strong net with high flexibility and energy absorption characteristics.

Bearing Ropes
Quantity
per fence segment
2
Max. Rope Diameter
[mm (inch)]
24
(0.945)
Corrosion ProtectionZn or ZnAl (Class A or B)
Brake Element
per rope
n/a
Brake Element Typen/a
Middle Ropes
Quantity
per fence segment
1
Max. Rope Diameter
[mm (inch)]
24
(0.945)
Corrosion ProtectionZn or ZnAl (Class A or B)
Brake Element
per rope
n/a
Brake Element Typen/a
Retaining Ropes
Quantity
per post
1
Max. Rope Diameter
[mm (inch)]
24
(0.945)
Corrosion ProtectionZn or ZnAl (Class A or B)
Brake Element
per rope
n/a
Brake Element Typen/a
Support Structure
Post TypeHEA/HEB
Post-Base Connection Hinged
Integrated LadderRungs every 0.5 m (19")
Rope GuidesIntegrated
Base Plate ConnectionTongue and pin
Anchors
per base plate
2
Post Base Support
Retaining Rope Anchorage
Lateral Anchorage

Lateral anchorage can be directly to a steep slope (e.g. gully embankments, as shown) or similar to a standard rockfall catchment fence. This allows the system to be used for protection against both confined or unconfined flows.

Typical Cross Section
Internal Stabilization
Typical Layout (Front View)

NOTE: All data is taken from an example of an existing project. Every avalanche structure is custom designed for a specific site and loading conditions and so the exact details of the system will very from site to site. This is an important aspect of avalanche mitigation since standardized (e.g. CE marked systems) cannot address site specific requirements.

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