No-pass channels: parameters and device

In civil and industrial construction, when arranging underground utilities, utilities, pipelines, heating mains, very often pass-through channels are used. So-called reinforced concrete products designed to protect finely laid engineering networks. What is the peculiarity of non-passable channels, what products have characteristics and what gives their use? About it - further.

Why are impassable channels needed and what is it?

All communication networks that are laid at shallow depths need to be protected from the influence of the external environment: very often pipelines are laid under roads, facilities under construction, etc. Thanks to the use of pass-through channels, the pipelines are protected from mechanical damage. What does impassable mean? This means that workers will not walk on the canal, therefore, they use these designs only when the laid communications do not need frequent repairs or constant maintenance.

Reinforced concrete products are made. They consist of 2 parts:

1. U-shaped frame element. It is installed and fixed at the bottom.
2. Bottoms. This is a flat element with low sides on both sides. Despite the name, the bottom does not fit on the bottom of the pit, but on top of the frame element. Thanks to this, a closed channel is formed in which the laid networks are located.

Both the bottom and the frame element are usually the same size. The products differ in the height of the sides and where the embedded elements and mounting loops are located.

Structural Features

For the manufacture of products of impassable types, manufacturers use only concrete of heavy grades. Reinforcement of products is carried out by flexible, but strong steel.

In the manufacture of pass-through channels, all recommendations mentioned in regulatory documents are strictly observed. Due to this, reinforced concrete elements possess the properties necessary for their operation:

1. Resistant to organic rot.
2. Durability.
3. Frost resistance - from F75 and above.
4. Water resistant above W4.

The advantages of reinforced concrete structures

The advantages of non-passable channels include such characteristics as:

1. Exceptional wear resistance - each product is designed for a life of 40 years or more.
2. Simple installation, which is possible at any time of the year, regardless of weather conditions.
3. Strength. Thanks to the reinforcement, the structures perfectly resist soil advancements, protecting the pipes inside.
4. Resistance to many aggressive environments.
5. Excellent tolerance to long and significant temperature changes.
6. Acceptable price.
7. Ease of manufacture. Designs have a simple form, which does not complicate their production, so manufacturers can always offer the necessary number of products needed for a particular object.

Product Classification

Impassable channels, according to their overall dimensions, are divided into several types (see table).

Note: in some cases, if necessary, manufacturers produce impassable channels weighing more than 2.4 tons. Such products are considered oversized and require the use of special vehicles for both transportation and installation.

The type of materials used in the production depends on the type of product. So, on a type construction from KN-1 to KN-4, concrete of class B15 is used. Only concrete of class B20 can be used to manufacture channels of impassable KN from grade 5 to 7. Reinforcement is carried out using steel Bp-I, A-III, AI.

Features of use

The regulatory requirements say that non-passable channels can only be used in the following cases when:

1. Networks pass through non-subsiding soils.
2. Soils are slightly aggressive to concrete.
3. Ground water at maximum rise does not reach the depth where the reservoir is laid.

The choice of the size of the pass-through channels, suitable for installation on a specific object, depends on several parameters:

1. The height of the supports.
2. The thickness of the pipeline insulation.
3. Distances at which neighboring communications are laid.
4. The presence of the road, sidewalk, which will subsequently pass through the paved system.

Installation and arrangement

The installation of impassable channels for water supply, heating mains and other pressure networks begins with the preparation of the pit. Its depth depends on the size of the installed elements. A pillow made of concrete or sand is equipped at the bottom of the pit. After that, U-shaped elements with a slight slope are installed, so that in case of condensation or moisture seeping from the soil, it flows to the place where it will be pumped out or it will gravity drain down to the ground.

After the pressure network is laid inside the lower element, the bottom is laid on top and the joints are sealed with concrete mortar. On top of the structure, a gluing or coating waterproofing is arranged and then a soil layer is poured. If there is a need to repair or replace the network passing inside the passageway, you will only need to dig up the soil to the point where the top of the protective element is located and raise it by hooking the structure to the mounting loops.

Because it’s quite difficult to get to the pressure line - you need to take out a significant amount of soil for this, the structures are used only on those networks where frequent repairs or constant maintenance are not needed.

Groundwater protection

Moisture is the main enemy of pipelines passing inside impassable channels: it destroys both the heat-shielding layer and the pipes themselves. So that in the spring or during a period of prolonged rains, sedimentary water does not fall into the channel, a drainage arrangement will be needed. It should be located on both sides of the track.

Perforated asbestos cement pipes are usually used as drainage. Under their installation, they dig a pit with a depth lower than the bottom of the collector. To the depth of the pit add 20-30 cm for drainage material. After that, a drainage of sand and gravel is arranged, on which a perforated pipe is laid. It is first covered with gravel so that water has access to the holes in the pipe. Only after that the drainage structure is filled with soil.