A highway is a very complex structure, for the design of which a huge number of different aspects are taken into account. This is the load on the canvas, and the intensity of car traffic, and much more.
Route performance
In this regard, for the full calculation of the transverse profile of the road, first of all, the characteristics of the traffic flow and the intensity of operation on the considered route are determined.
Mainly consider parameters such as:
- Intensity of track use. This concept includes an estimate of the number of vehicles passing through a given section in the time allotted for measurements. When calculating the intensity, the average is taken, as well as the planned and actual.
- The capacity of a highway refers to the concept that takes into account the number of vehicles passing through the transverse profile of the road at a certain time.
- The speed of the traffic flow is the average speed of all cars moving along the studiedsection of the track.
- Traffic density is the average number of vehicles simultaneously located on the studied section of the route.
- The amount of goods transported through the study section of the road is called the traffic density.
There are also such concepts as roughness and evenness. They determine the quality of the roadway on the studied transverse profile of the road. All these data are necessary when working on the track, both as part of its repair and at the design stage.
How they are classified
The cross profile of a road depends on which category the road belongs to. It can be a main line, that is, one that connects international roads. Passengers and goods of the transit category are transported through it.
Regional routes include roads connecting the capital of the state with the capitals of the regions. Territorial routes are motor roads connecting settlements of separate regions. Regional roads connect regional centers and small settlements of a certain region.
The cross profile of the road depends entirely on the category of the track, since they all have their own load. The only thing common between all types of track is their expected service life. It's at least 20 years old. All this time, the transverse profile of the highway should not require serious reconstruction or repair, even if the load on the highway increases sharply. These possible spikes in workloadtaken into account during road design.
Track
The term "highway" applies mainly to topographic roads, that is, mapped or mapped in the form of a horizontal layout of its location. The track can also be viewed in a longitudinal profile to show the terrain and follow the road.
The longitudinal profile of the road in the design is a very important component of the calculations. If this characteristic does not meet the requirements of safety and convenience for transport, then the soil in this place is removed, making the elevation changes of the road smoother.
If the difference in elevation is so sharp that it does not meet the requirements, then the lowlands are filled up. In other words, the route is the direction on the diagram, taking into account the elevation changes.
Road. Definition
The road arrangement includes a carriageway, a roadside, a slope of a dirt bed and a ditch. The roadbed can be with or without a dividing strip. It depends on the width of the canvas. For example, roads with 2, 3 or more lanes must have a dividing line.
The roadside is a dirt cover at the same height as the road, its width may vary depending on environmental conditions and technical specifications when designing an object. Usually they try to make the shoulder wide enough so that it is safe for the main traffic to stop the car.
Earth embankment
The width, height and angle of the earth slope depend onhow high above ground level the road was built. The slope gives the road the necessary strength. It is calculated taking into account the materials used in the construction and the characteristics of the soil. The soil cushion, the edge of which is a slope, is a multilayer structure consisting of various materials - pebbles, sand, gravel. Taking care of the slope is just as important as taking care of the roadbed, because if it collapses, the whole road will sag.
The height of the embankment largely depends on the terrain along which the track runs. If heavy snowfalls are possible in the region, then the embankment is made of sufficient height so that the snow does not cover the road. If the route runs through a flat steppe, in a hot region with low rainfall, then the embankment will be no more than 1 meter in height. The angle of the earthen slope depends on what load is planned for this road. On large highways with a high density of traffic, the earthen slope has a very obtuse angle, which increases the strength of the road. Conversely, a low load on the road allows you to make the slope steeper in relation to the canvas. But in this case, additional reinforcements in the form of pillars, fences or plant roots will be needed.
Cuvette
The ditch serves as a drainage ditch, through which excess water is removed from the embankment. The construction of the road involves the placement of drainage pipes and channels in the ditch, the main task of which is to save the bulk of the road from erosion. This is especially true during the spring rains, coupled with massive snowmelt.
Cross profile
The cross section of the road is a section of the roadbed and its substrate perpendicular to the longitudinal axis of the road. How often is it applied? The construction of roads widely uses the transverse profile for the design and support of work on the arrangement of the pillow and the roadway itself.
Cross profile on embankment
Typical cross profile of a road shows the road surface with medians and road edges, shoulders, slopes and drainages. All this is a necessary condition for the operation of the route.
There are different types of cross sections of highways. For example, these are profiles on embankments. This type of road is very common, in almost any area, in any climatic region.
When building a track, it is important to make a streamlined profile. The height of the embankment can vary from 1 to 20 meters. A characteristic feature of this road is the streamlined shape of the transverse profile, which allows rainwater and melting snow to drain. The ditch is made by excavating the soil along the earthen backfill of the road. If natural conditions allow, then the road embankment is made from soil taken along the track, if not, then it is brought from special quarries.
Sometimes a paved road is not streamlined. In this case, it is absolutely flat, and water is removed from its surface using other technologies.
The construction of roads is not only on relatively flat ground,but also in remote mountainous areas. In this case, streamlined and non-streamlined profiles are built on slopes. The installation of such a road is possible only at a certain angle of the slope. If it is more than allowed, then the road is moved or the mountain is adjusted to the necessary conditions by explosives technicians or sinkers.
But even on such a mountain road, with slopes, all the elements of the transverse profile of the road are present - the shoulder, the ditch and the reserves from which the soil for the embankment was taken.
Cross profile in recess
Some applications require a paved road on un-filled terrain, in lowlands, in loose soil conditions, or in the middle of arable fields. There are few such roads. But they are necessary. These are roads with a transverse profile in the cut.
They represent a streamlined profile recessed into the ground. If construction conditions allow, then along such a road a ditch is arranged, which makes the canvas elevated, but not to the level of the upper edge of the soil.
The depth of such a road can be up to 12 meters below ground level. And it doesn't matter how wide it is. Even the transverse profile of a category 4 road suggests the presence of shelves in the recesses for organizing snow dumps, despite the fact that such a road has only 2 lanes.
The shelf is also necessary on mountain roads, as weathering and natural rock erosion take place in them. And small fractions that have broken off from the rocks accumulate in special recesses along the canvas.
If the slope is onroad with a transverse profile in the recess is quite high, then it is made in the form of ledges. This allows you to make the walls stronger, which keeps them from falling.
Classification
The technology of asph alting roads and their operation depend on the category of the route. The first category includes roads with the number of lanes from 4 to 8 and the width of the roadway up to 15 meters. And the width of the subgrade, together with the curb and the slope of the embankment, can be up to 40-45 meters. Roads of the second category have 2 lanes with a total width of 7.5 meters, and the total width of the road is 15 meters.
Roads of the third and fourth categories also have 2 lanes, but differ in the width of the roadway and the width of each lane. Category 3 includes tracks with a lane width of 3.5 m, a roadbed of 7 meters and the entire road as a whole - 14 meters. And category 4 includes lanes with a width of 3 meters, a 6-meter canvas and 12 meters of the road itself.
The technology of road paving is based on these standards in most civilized countries. In addition, no matter what category the road under construction belongs to, it is necessarily equipped with ditches, drainage, has a shoulder, and its slopes are strengthened with concrete or plants. Road markings are also required.
Additional facilities
Any route has a number of additional structures that are necessarily included in the project documentation. Moreover, some of them are indicated in the transverse profile of the road. For example, a transverse pipe for a stream that crosses a road.
Pedestrian bridges or underpasses can also be installed across the road. The road can pass over the bridge, it is indicated in the plan as an additional structure of the route.
The bridge can pass not only over the river, but also over a deep ravine and gorge. In this case, it is called a viaduct and is arranged in the form of an openwork structure, under which the movement of pedestrians or water transport is not expected. The viaduct is usually single-lane, and there is rarely heavy traffic on it. Most often, the viaduct is created for the construction of the railway.
Mountain roads are protected from snowfalls, avalanches and rockfalls by galleries. The same category of protective equipment includes concrete pillars along the road. In the project documentation, they are called retaining walls.
Additional facilities include traffic police posts with all the necessary facilities. There are bus stops on any road, even on international routes. Therefore, this building is classified as an additional building.
Importance of tracks
Roads are everywhere in today's world. It is difficult to imagine a place or environment without roads. They can pass along mountain serpentines and through the mountains themselves. Through the sands of hot deserts and impenetrable taiga forests. Even under the bottom of the ocean, roads are laid, for example, under the English Channel.
Roads bring people and countries together. And these structures have existed for more than a century. Suffice it to recall the Great Silk Road - the road that unites Europe and Asia. Without roads there can be no economicgrowth and cultural exchange between countries and peoples.
In the old days, goods and people were transported by small ships. In this regard, the economy developed only in those countries where there were enough rivers. Where there were few of them, they remained in cultural and commercial isolation.
Only thanks to modern roads, such a science as logistics began to develop. The machine-building industry and the energy industry received a boost.
Conclusion
The construction of roads has become so profitable and at the same time labor-intensive, that in all countries road institutes have begun to be organized, in which young specialists comprehend the complexity of the construction process. A road engineer is able to design from scratch and then control the process of building a road. And most importantly, to correctly and economically monitor the state of the constructed object.
