Longitudinal slope of the road snip. Road classification

All roads in Russia, depending on the value, are divided into national, republican, regional, local. Depending on the purpose, intensity and speed of traffic, roads are divided into 5 categories.

Roads of category I (motorways and freeways) have a carriageway width of 15 m more with a dividing strip separating wind currents Vehicle. Two or more traffic lanes are provided for each direction (lane width 3.75 m). These improved roads concrete pavement designed for mass movement vehicles. The longitudinal slope of the carriageway does not exceed 3% (i.e., at a distance of 100 m, the roadbed can rise or fall by no more than 3 m). The capacity of such a road is more than 7,000 vehicles per day at a speed of up to 120 km/h on rough terrain and 150 km/h on flat terrain.

Highways of the II category with an asphalt surface are built to connect industrial, administrative and cultural centers. The width of the carriageway is at least 7.5 m, the longitudinal slope does not exceed 4%, the throughput is 3000-7000 cars per day at a speed of up to 120 km/h.

Roads of category III with a carriageway width of at least 7 m are built according to lightweight technical requirements. They may also have cobblestones. Longitudinal slope - no more than 5%. These roads are capable of passing up to 3,000 vehicles per day at a speed of up to 100 km/h.

Category IV roads with the simplest surface are provided for low-intensity traffic. Car traffic on such roads in the spring-autumn period is difficult. The width of the carriageway is 6 m. The longitudinal slope can reach 6%. The capacity is 200-1000 vehicles per day at a speed of up to 80 km/h.

Roads of the V category have a lower type of coverage or do not have it at all. The width of the carriageway is 4.5 m, and the longitudinal slope can be 7%. Such roads are capable of passing no more than 200 transport units per day at a speed of up to 60 km/h.

Construction of a modern road

A modern motor road is a complex transport structure on a specially designated area of ​​land - the right of way. They suit her carriageway on which vehicles are moving. For driving comfort, increase bandwidth of the highway and ensuring traffic safety, the roadway is made with a hard surface (concrete, asphalt and other building materials). When designing and constructing a road for single-lane traffic in opposite directions, the width of the carriageway is provided for at least 7 m. bike paths, placement of green snow and forest protection plantings, installation of drainage structures, storage of materials for repairs highways.

The earthen (road) bed, in addition to the carriageway, includes two shoulders - to the right and to the left of the carriageway. The curb serves for an accidental or forced exit from the carriageway. It can be used as a reserve lane when expanding the roadway, oncoming sidings. It has a width of 2 "3.75 m (on roads of categories I-IV). To drain rain and snow water, side channels (cuvettes) with a depth of 0.3 1 0.8 m are arranged along the roadway. metal fences in the form of columns or breaking bars. In those places of the road where it changes direction, for the convenience of movement in the turning sections, yes, the horn is built along smooth circular curves. The steepness of the turns of the road is characterized by the magnitude of the angle of rotation and the radius that describes the curved section of the route.

On curved sections of the road, traffic conditions are complicated. Here, a lateral inertial force arises, which tends to displace, and in some cases even overturn the car in the direction opposite to the turn.

In order to ensure the runoff of water from the surface of the road, during construction it is not built flat, but convex, in the form of a gable cover. The angle of inclination of the transverse profile of ordinary roads is small - only about 1.5-4%. Such an angle is sufficient so that the water does not linger on the road surface, but flows freely into the ditch.

On straight sections of the road, the presence of a transverse slope of the surface does not create noticeable difficulties for the movement of cars. However, on turns, those cars that pass along the road lane outer to the turn are in unfavorable conditions, since the lateral inertial force acting on the turn is added to the gravity component resulting from the inclined position of the road surface; vehicle stability deteriorates. In addition, the driver has a feeling of uncertainty associated with the uncomfortable position of the torso and the influence of lateral inertial force, the conditions for visual perception of the rounding worsen. In order to reduce the impact of these factors and facilitate the process of control, the cross profile of roads is often made single-slope when cornering. Such a profile (turn) greatly facilitates the control of the car on the turn and increases the safety and comfort of passengers and the driver. In addition, this allows you to significantly increase the speed of cornering. Therefore, the turn becomes obligatory element modern expressway.

TO category:

Construction of roads

Road classification

An automobile road is a complex of structures designed for the carriage of passengers and goods by cars and ensuring year-round continuous, safe and convenient movement of vehicles at design speeds and loads. The composition of the road includes subgrade, pavement, bridges, tunnels, pipelines, retaining walls. The road will be equipped road signs, recreation areas, filling stations with fuel and lubricants and parking facilities.

Roads are divided into the following groups.

Roads of national importance connect the capitals of the Union republics, large industrial and cultural centers, resorts of allied significance, as well as the capital of the USSR with major centers neighboring states. These roads are of the highest technical perfection.
Roads of republican significance connect the main administrative, cultural and economic centers of the union republics, territories and regions with the capital union republic and among themselves.

Roads of local importance are divided into roads of regional, regional, district significance and economic or departmental roads. Departmental roads are intended for communication between collective farms, state farms, factories. Local roads serve individual farms and departments.
Roads and streets of populated areas are used for transport communication within the borders settlements. Some of these roads and streets may serve as transit traffic.

According to the technical level, motor roads are divided into five categories (SNiP N-D.5-72). The classification is based on the national economic significance of roads, traffic intensity per day (Table 1) or annual traffic density and other indicators.

Table 1. Main technical indicators of roads

Category IV includes motor roads of regional or district significance, local roads, access roads of a general network, industrial enterprises, large construction projects, state farms and collective farms. For access roads of industrial enterprises, where vehicles of especially large carrying capacity and dimensions are used, a traffic density of 1 million tons per year or more for category III and less than 1 million tons per year for category IV is established.

The width of the carriageway of streets and roads is set according to (SNiP P-60-75) depending on the traffic intensity in one hour, but not less than that indicated in Table. 2. Express roads are designed for movement at a design speed of 120 km/h.

Table 2. Width of streets and roads

The capacity of one traffic lane of the carriageway is, pcs.:
Passenger cars - 600-1500;
Freight - 300-800;
Buses - 100-300;
Trolleybuses - 70-130.

The width of the carriageway of the main roads is 7-15 m and provides the passage of all types of transport, industrial - 6-7 m. The latter connect shops and other objects with each other and with the main roads. The width of the carriageway of driveways and entrances is 4.5-6 m.

Highways are structures of various lengths made of soil and other road construction materials, designed for the passage of road transport and connecting cities, towns, factories, farms, etc. to each other. automobile transport currently accounts for up to 75% of transported goods, and every year specific gravity road transport will increase.

Depending on their purpose, motor roads are divided into union, republican, regional and local. There are also intra-farm, city, industrial, and resort roads. From the point of view of their design, arrangement, lighting and the duration of their use per year, motor roads can be divided into motorways and local roads. permanent action throughout the year, seasonal, used only in winter (ice, winter roads), and natural, suitable for travel in certain time of the year.

In the USSR, a general technical classification of motor roads is currently in force, depending on their significance and traffic intensity. According to SNiP P-D.5-72, they are divided into five categories.

Highways of industrial enterprises connect the sites of factories, mines, power plants, quarries. The construction of these roads is technological process production of works at the enterprise. These roads are divided into three types: main, industrial, driveways and entrances.

The width of the carriageway of the main roads is 7-15 m and provides the passage of all types of transport, industrial - 6-7 m.

The latter connect workshops and other facilities to each other and to main roads. The width of the carriageway of driveways and entrances is 4.5-6 m. They are intended for the transportation of goods of non-core production.

The traffic density of driveways and entrances is less than 600 thousand tons per year.

Motor roads, depending on their importance in the general transport network of the USSR and the size of the average daily traffic intensity, are divided into the following five categories:
I - highways of national importance, the main trunk roads of republican significance with a traffic intensity of over 6,000 vehicles per day;
II - highways of national importance, the main trunk roads of republican significance with a traffic intensity of 3,000 to 6,000 vehicles per day;
III - highways of republican or regional significance, linking economic and administrative regions, industrial and cultural centers and having a traffic intensity of 1,000 to 3,000 vehicles per day;
IV-V - highways, which, as a rule, have local economic and administrative significance.

The traffic intensity for category IV roads is from 200 to 1000 vehicles per day, and for category V roads - less than 200.

Depending on the category of the road, cars can move along them at different speeds. These speeds are calculated, they can be used to judge the main parameters of the road. The estimated speeds of vehicles on the roads are: for category I - from 80 km/h in mountainous areas to 150 km/h in flat areas; for category II - from 60 to 120 km / h, respectively, for category III - from 50 to 100 km / h, for category IV - from 40 to 80 km / h and for category V - from 30 to 60 km / h . Depending on the category of the road and the estimated speed of movement, the main parameters of the subgrade and the carriageway are determined.

In the USSR, the following main parameters of the subgrade and carriageway for roads have been adopted various categories(Table 1).

Roads are built with various types pavement and roadways. The choice of one or another type of pavement and pavement design is made on the basis of transport and operational requirements, road category, composition and traffic intensity, climatic conditions and availability of local building materials.

In order to improve economic efficiency capital investments, sometimes pavements and pavements are built in stages, i.e., pavements and pavements of a transitional type are built with their subsequent transfer to a higher class.

In our country, the following main types of coatings are accepted:
improved capital:
a) cement concrete - monolithic and prefabricated;
b) asphalt concrete - laid in a hot and warm state; from durable crushed stone materials of a selected composition, processed in mixers with viscous bitumen or tar;
c) paving stones and mosaics on a stone or concrete base;
advanced lightweight:
a) from crushed stone and gravel materials treated with organic binders;
b) from cold asphalt concrete;
c) from soil treated with viscous bitumen in the plant;
transitional:
a) crushed stone from natural stone materials and slags, as well as gravel;
b) from soils and local weak mineral materials treated with liquid organic binders;
c) pavements made of cobblestone and chipped stone;
lower coverings: ground, reinforced with various local materials.

Asphalt concrete pavements are laid from granular mixtures that provide strength, durability and sufficient shear resistance of the pavement, as well as a rough surface without surface treatment.

Cement-concrete pavements are laid in areas insufficiently provided with local stone materials, in the presence of heavy traffic, under unfavorable soil and hydrological conditions.

Pavements made of paving stones, mosaic tiles and concrete slabs used on road sections within settlements, high embankments and other places where subgrade precipitation is possible.

Cobbled and mosaic pavements are laid in places with the movement of caterpillar vehicles.

Coatings from cold asphalt concrete, crushed stone and gravel materials treated with organic binders (bitumen, tar, emulsions) are built at a traffic intensity of 1,500 to 3,000 vehicles per day.

Coatings from soils and local weak mineral materials treated with liquid binders are satisfactory with a traffic intensity of 500 vehicles per day.

To protect against destruction of road pavements, wear-resistant protective layer by double surface treatment. Surface treatment includes the following work: preparation of the surface to be treated, usually the layout of the base; bottling of binder material, performed by asphalt distributors, distribution stone material with a layer thickness of one gravel, leveling of the distributed material and its compaction. With double and triple surface treatments, these operations are performed 2 or 3 times, respectively.

TO Category: - Construction of highways

The width of the carriageway of roads within the middle part of concave curves in the longitudinal profile, mating sections of longitudinal slopes with an algebraic difference of 60‰ or more, should be increased on each side for roads of categories II and III by 0.5 m, and for roads of categories IV and V - by 0.25 m compared with the norms given in Table. 4*.

The length of sections with a widened carriageway should be at least 100 m for roads of categories II and III, and at least 50 m for roads of categories IV and V.

The transition to the widened carriageway should be carried out on a 25 m section for roads of categories II and III and on a section of 15 m for roads of categories IV and V.

4.9. On sections of roads of category V with slopes of more than 60 ‰ in places with unfavorable hydrogeological conditions and with easily eroded soils, with a reduced width of the shoulders, provision should be made for the arrangement of passing roads. Distances between sidings should be taken equal to the visibility distances of an oncoming vehicle, but not more than 1 km. The width of the subgrade and the carriageway at the sidings should be taken according to the norms of roads of category IV, and the smallest length of the siding - 30 m. The transition from a single-lane to a two-lane carriageway should be carried out for 10 m.

4.10. The width of roadsides in particularly difficult sections of mountainous terrain, in areas passing through especially valuable land, as well as in places with transitional speed lanes and with additional lanes for climbing, with an appropriate feasibility study with the development of measures for the organization and traffic safety is allowed reduce to 1.5 m - for road I-a, I-b and II categories and up to 1 m - for roads of other categories.

4.11. The width of the separate lane on road sections, where in the future it may be necessary to increase the number of lanes, should be increased by 7.5 m against the norms given in Table. 4*, and be taken equal: for category I-a roads - at least 13.5 m, for category I-b roads - at least 12.5 m.

The surfaces of the dividing strips, depending on their width, the soils used, the type of fortification and the natural and climatic conditions, are given a slope towards the middle of the dividing strip or towards the carriageway. When the surface of the dividing strip slopes towards the middle, special collectors should be provided for water drainage.

4.12. The width of the median on sections of roads laid on valuable land, on particularly difficult sections of roads in mountainous areas, on large bridges, when laying roads in built-up areas, etc. with appropriate feasibility studies, it is allowed to reduce to a width equal to the width of the strip for installing fences plus 2 m.

The transition from the reduced width of the dividing strip to the width of the strip adopted on the road should be carried out on both sides with an offset of 100: 1.

Dividing lanes should be provided with breaks 30 m long every 2-5 km to organize the passage of vehicles and for the passage of special vehicles during periods of road repair. During periods when they are not in use, they should be covered with special removable guards.

4.13. The width of embankments of highways on top at a length of at least 10 m from the beginning and end of bridges, overpasses must exceed the distance between the railings of the bridge, overpass by 0.5 m in each direction. If necessary, an appropriate widening of the subgrade should be carried out; the transition from the widened subgrade to the standard one should be carried out at a length of 15 - 25 m.