The main elements of the highway. The main elements of the highway
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Introduction
Highways are a complex of engineering structures designed to ensure year-round, continuous, convenient and safe movement of vehicles with a design load and set speeds at any time of the year and in any weather conditions. This complex includes subgrade, pavement, bridges, roadsides and other artificial structures, road construction and protective road structures, buildings and structures of road and motor transport services.
The parameters and condition of all elements of the road and road structures determine the technical level and operational condition of the road.
To the main transport and operational indicators highways and road structures include the provided speed and throughput, continuity, convenience and safety of traffic, the ability to pass cars and road trains with an axle load and a total mass corresponding to the category of the road.
Technical instructions for strengthening roadsides.
These standards are intended for the selection of materials and structures for reinforcing shoulders. They take into account the provisions of the existing normative documents for the design, construction and repair of roads, the organization and provision of traffic safety on them.
Table 1.
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Road options. |
Value |
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Road width |
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Number of traffic lanes |
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|
Estimated traffic intensity |
auto/day |
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Shoulder width |
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|
Roadway Width |
|||
|
Lane width |
|||
|
The smallest width of the reinforced shoulder strip |
1. Organizational part
A section of the road provided to me for observation and execution term paper located on the section of the district road p.Solnechny-p.Beryozovy. The section starts from 0 km. the village of Berezovy and ends near the village of Gusevka. The length of this section is 10 km. This gravel road belongs to the III category of the road. There are two bridges across the river. Amgun, and the river Veli, as well as a viaduct on the road. Highway Komsomolsk-on-Amur - pos. Berezovy is part of the former technological road that served for the construction of the Baikal-Amur Mainline. The entire length of the road was built in close proximity to the railway. The existing road has a large number of turning angles with small curve radii in the plan. The roadway is in poor condition. The cross slope is not maintained. Most of the artificial structures presented in a wooden version are in disrepair or completely destroyed. On the separate sections This road is a winter road (traffic is carried out only in the winter period). Since 2007, work has begun to bring the highway to the parameters of category IV along its entire length with artificial structures of a capital type. The pavement is gravel with the prospect of its further transfer to asphalt concrete pavement. The intensity of traffic on this road is 650 vehicles per day, 210 of which are trucks and about half weighing more than 60 tons.
1.1 General provisions and concepts used in the project
The operation of roads is understood as the expedient and efficient use of roads by vehicles for the transport of goods and passengers.
The operational state is the degree of compliance of the variable parameters and characteristics of the road, engineering equipment, organization and traffic conditions that change during operation as a result of the impact of vehicles, meteorological conditions and the level of maintenance with regulatory requirements (strength of pavement, road surface condition, actual used width of the carriageway parts and roadsides, traction and evenness of the surface, condition of engineering equipment, road markings, entrances and
relocations). Traffic safety - state this process reflecting the degree of protection of its participants from traffic accidents and their consequences. Road structures - structures that are structural elements of the road: artificial structures (bridges, overpasses, overpasses, pipes, tunnels, etc.), protective structures (snow protection forest plantations, permanent snow protection fences, noise protection devices, devices for protecting roads from snow avalanches and landslides, etc.), elements of road arrangement (stop and landing sites and pavilions for passengers), recreation areas,
special areas for stopping or parking cars, etc. Repair of a highway is a set of works to reproduce its original transport and operational characteristics, in which the wear of the coating is compensated, its evenness and grip are restored and improved, and all deformations and damages are eliminated pavement, subgrade, road structures, elements of the situation and arrangement of the road, organization and provision of traffic safety.
2 . Climatic characteristics of the area where the highway is locatedaboutgi
2.1 Geographical position, terrain
The Solnechny District includes 11 municipalities uniting 19 settlements. The administrative center is the working settlement Solnechny. The area of the district is 31.1 thousand square meters. km (4% of the territory of the region). Assigned to areas equated to the regions of the Far North.
The Sunny District is located in the central part of the region on the left bank of the Amur, in the valleys of the Amgun, Evur and Gorin rivers. The district has borders with Khabarovsk and Amur regions in the south, Komsomolsk and Ulch regions in the east, with the district named after. Polina Osipenko in the north and with the Verkhnebureinsky district in the west. According to the nature of the relief, the territory of the region is divided into three parts: the western mid-mountain one, occupied by the Bureinsky and Badzhilsky ridges, low-mountain (north-east and east) and the middle plain, which is represented by the Evoron-Chukchagir lowland.
2.2 Climatic features of the area in accordance with SNiP 23-01-99 "Construction climatology"
The territory of the district belongs to a moderately cold climate with a strong influence of monsoons, which determine the seasonal change of winds. average temperature in January - -35°С, in July - +25°С, the average annual precipitation is 470-700 mm. The duration of the frost-free period is 100-130 days, the period with temperatures above +10°C is 100-110 days a year.
Table 2.1 Average monthly and annual air temperature, °С
Diagram of the wind rose in the village of Solnechnoye for March 2014
3 . Requirements for performance indicators and levels of aintomobile roads
This standard establishes a list and permissible under the conditions of ensuring traffic safety limit values of indicators of the operational condition of roads, streets and roads of cities and other settlements, as well as requirements for the operational condition of technical means of organizing traffic.
All requirements of the standard are mandatory and are aimed at ensuring road safety, saving life, health and property of the population, protecting environment.
The standard applies:
Until 01.01.95 on federal highways, main roads and streets of cities and other settlements that are in operation;
From 01.01.95 to all operated roads common use with cement concrete coating and any coating of bitumen-mineral mixtures and on all roads and streets of cities and other settlements.
Motor roads, roads and streets of cities and other settlements, according to their transport and operational characteristics, are combined into three groups:
Group A - highways with a traffic intensity of more than 3000 vehicles / day; in cities and settlements- main roads of high-speed traffic, main streets of citywide importance of continuous movement; group B - motor roads with traffic intensity from 1000 to 3000 vehicles/day; in cities and towns - main roads of regulated traffic, main streets of citywide significance of regulated traffic and regional significance;
group B - roads with a traffic intensity of less than 1000 vehicles / day; in cities and towns - streets and roads of local importance;
The requirements established by the standard must be provided by organizations in charge of roads, as well as streets and roads of cities and other settlements.
In the event that the operational condition of roads and streets does not meet the requirements of this standard, temporary restrictions must be introduced on them to ensure traffic safety, up to a complete ban on traffic.
|
Characteristics of content levels |
|||
|
Permissible level |
Road maintenance provides allowable level traffic safety in accordance with GOST R 50597-93 "Automobile roads and streets. Requirements for the operational state permissible under traffic safety conditions." It is allowed to temporarily restrict or temporarily stop the movement of vehicles in certain areas according to the conditions of their maintenance. There are no accidents due to poor road maintenance |
||
|
Middle level |
The maintenance of the road provides a level above the permissible level. The state of structural elements, depending on the content, does not necessitate a temporary restriction or temporary suspension of the movement of vehicles. It is allowed, according to the conditions of detention, to reduce the speed of cars allowed by the rules of the road in certain sections, up to 20% of the total length. Deterioration of traffic conditions due to keeping in areas located in settlements, on curves of a small radius, long descents and ascents and on cross roads is not allowed. There are no accidents due to poor road maintenance |
||
|
High level * |
The maintenance of the road provides a level above average. The highway and each of its structural elements are kept in a condition that ensures round-the-clock, uninterrupted and safe movement of vehicles. It is not allowed to reduce the speed of vehicles below that permitted by the Rules of the Road for reasons related to road maintenance. Minor defects in structural elements are allowed, which do not affect the speed and safety of movement. There are no accidents due to poor road maintenance |
AT autumn period to ensure minimal soil moisture by precipitation and reduce the degree of waterlogging in spring next year carry out systematic cleaning of the mouths of culverts and drainage ditches (cuvettes) from foreign objects and dirt, carry out pre-winter planning of summer and tractor tracks, unfortified roadsides. In complex ground and climatic conditions, especially on the abyss hazardous areas, limit the arrival of cars on unreinforced roadsides. During this period, as well as in the spring, the road service must take measures to prevent the use of the right of way for the drive and pasture of livestock,
In the spring, the roadway is cleaned of dirt and snow or ice crust as it melts.
Cleaning of coatings from dirt in the spring is carried out within 3-5 days after the road is freed from snow and ice, until the dirt has dried up and is easily removed by a motor grader or bulldozer.
During the period of strong moisture, the roads (if necessary) are closed. Traffic should be opened after the roadway has dried and its surface has been leveled. In cases where it is not possible to completely close the traffic (harvesting, fertilizer removal, etc.), patrol maintenance of the road is organized by specialized units or brigades, including with the performance of work.
4 . Assessment of the transport and operational condition of the road
4.1 Determination of the estimated traffic volume of vehicles
Estimated (prospective) traffic intensity (Np, avt/day) is determined based on field measurements in order to establish the category of the road and the basic requirements that it must meet. When determining Nr. sequentially set the actual reduced intensity of traffic at a given hour of the day (N f.pr), the reduced intensity at any hour of the day (N r j) and the average daily reduced traffic intensity of vehicles during the measurement period on the road.
; N prospect = 466(1+0.04) 9 =632 auto/day, (4.1)
where N 1 is the intensity of the traffic flow on the road in the estimated period of the year, avt / day;
b - coefficient of annual increase in traffic (0.04);
t is the estimated period of pavement operation, years.
Years; t=15-6=9 years, (4.2)
where T 0 - design estimated service life of pavement, 15 years;
T f - the actual service life of pavement, 6 years.
The intensity of the traffic flow is determined by the formula:
; N 1 = 31*2 * 7*0.94, =466 auto/day, (4.3)
where N hour is the intensity of the traffic flow measured for one hour during the test period, avt/hour;
K 1 - the coefficient of reduction of the average hourly traffic intensity to the average daily 9.9
K 2 - the coefficient of reduction of the average daily traffic intensity during the test period to the intensity corresponding to the billing period of the year, 0.94
4.2 Determination of pavement safety factors
The strength of a pavement is considered sufficient when its actual modulus of elasticity, determined as a result of field tests, is not less than that required by the type of pavement and traffic conditions.
where E f - the actual modulus of elasticity of pavement according to field tests, MPa;
E tr - the required modulus of elasticity of the pavement, taking into account the existing composition of vehicles and the intensity of the impact of traffic loads on the pavement, MPa.
4.3 Determination of the transport and operational condition of the road
The partial coefficient K pc1 is determined depending on the width of the main fortified surface used for traffic, the number of lanes and traffic intensity.
; B 1f \u003d (10 + 2. 0.5) . 0.96=11.56 (4.5)
where B p is the width of the carriageway. m;
b y - width of the edge fortification strip, m;
K y - coefficient of use of the width of the main reinforced surface, 0.96.
K pc2 is determined by the width of the shoulder
in i - width of the roadside with different type fortifications;
K pc2 i - the value of the coefficient of ensuring the design speed for a given type of strip strengthening;
In about - the total width of the curb;
n is the number of types of roadside reinforcements
Private K pc3 is determined depending on the intensity and composition of traffic
where DK rs - reduction of the design speed security factor under the influence of traffic intensity and composition, 0.05.
4.4 Determination of a comprehensive indicator of the transport and operational condition of the road
The transport and operational state of each characteristic section of the road is estimated by the final coefficient of design speed, which is taken as a complex indicator of the transport and operational state on this segment.
KP d i \u003d K rs i total (4.8)
The value of the final coefficient of provision of the design speed in each section for the spring-autumn calculated according to the traffic conditions
period of the year is taken equal to the smallest of all partial coefficients in this area.
K rs i total = K rs i min (4.9)
4.5 Assessment of the transport and operational condition of the road
The assessment of the transport and operational state of the road of this category at the time of the survey is carried out according to the value of the complex indicator.
KP d = ; (4.10)
KP d n = 0.70
KP d k \u003d 0.76
where K rs i total - the final value of the design speed security factor in each section;
li - the length of the section with the final value of K pc i total;
L is the total length of the road.
The change in the state of the road for the period between surveys is estimated by the magnitude of the increase in the complex indicator of the transport and operational state of the road.
The increase in the indicator of the transport and operational state of the road is determined by the formula:
KP q = , (4.11)
where KP d k, KP d n - indicators of the transport and operational state of the highway at the beginning and end of the period under review.
KP d = = 8.6%
Conclusion: after the completion of the work, the indicator of the transport and operational condition of the highway will improve by 8.6%.
Table 4.1.1
|
Vehicle brand |
Actual hourly intensity |
Reduction factor |
Share in the traffic flow |
||
5. Technological part
5.1 Definition of types of work
Planning of repair work is carried out on the basis of the results of diagnostics and assessment of the condition of the highway.
Work planning is carried out according to the criterion of economic efficiency, which is the most optimal from the point of view of the economic feasibility of spending funds.
Based on this criterion, for each possible object, we compare the costs of road works and the effects that they will provide.
As a result of the analysis of the actual private coefficients for ensuring the estimated speed, we establish the parameters and variable characteristics of the road, which caused a decrease in the transport and operational state of the road.
The sequence of work on the repair of roadsides
1. Organization of vehicle traffic at the work site
2.Preparation of the site for roadworks, garbage collection, removal
shrubs and trees.
3. Pouring roadsides
4. Layout of roadsides, mechanized way with help
Motor grader.
5. Slope planning
6. Soil compaction with a vibratory roller.
7. Cleaning up soil residues and other debris.
6.Scope of work on the repair and maintenance of the highway
Road maintenance works include:
a) keeping the right of way, roadsides, slopes and medians clean and tidy; cleaning them from garbage and foreign objects with removal and disposal at landfills;
b) leveling the slopes of embankments and excavations, repairing damage with the addition of soil and strengthening by sowing grasses;
c) maintaining the elements of the drainage system clean and tidy (including cleaning, profiling, strengthening the walls and bottom of ditches and drainage ditches, eliminating defects in their reinforcements, cleaning and eliminating minor damage storm sewer, drainage devices, fast currents, water wells, drops, trays, inlet and outlet channels near pipes and bridges);
d) arrangement of drainage slots;
e) anti-flood measures;
f) cutting, backfilling, leveling and compaction of unreinforced roadsides with draining soil up to 10 cm thick; backfilling, leveling and compaction of crushed stone and gravel roadsides; elimination of deformations and damages on reinforced roadsides;
g) restoration of the subgrade in areas with heaving and weak soils in an area up to 100 m2;
h) elimination of exits from motor roads (entrances to motor roads) in unspecified places;
i) maintaining the cleanliness and order of the elements of designation of the boundaries of the right of way;
j) liquidation of the consequences of collapses, scree, landslides and mudflows, other anti-landslide measures;
Winter maintenance includes:
1) maintenance of permanent snow protection structures;
2) arrangement of snow measuring posts necessary for studying the operation of roads and road structures in winter conditions;
3) preparation, installation, rearrangement, cleaning and restoration of temporary snow-retaining devices (shields, fences, nets, etc.), signal milestones; formation of snow banks and trenches to retain snow on the roadside and their periodic renewal;
4) mechanized snow removal, clearing roads from snow drifts, combating winter slipperiness, cleaning snow banks from roadsides;
5) profiling and compaction of snow cover on the carriageway of motor roads with a transitional or unpaved surface;
6) loading and removal of snow, including its disposal;
7) distribution of anti-icing materials;
8) regular cleaning of snow and ice from the elements of the arrangement, including bus stops, pavilions, recreation areas, berms of road signs, fences, sidewalks, footpaths and other objects;
9) removal of snow and ice from the elements of the bridge deck, as well as the zone of interface with the embankment, under-farming platforms, bearing parts, superstructures, supports, cones and regulatory structures, approaches and stairways;
10) round-the-clock duty of mechanized teams for snow removal and combating winter slipperiness, patrol snow removal;
11) arrangement, maintenance of cleanliness and order of winter roads (winter roads);
7 . Acquisition of technological links for the repair and maintenance of the road
Table 7.1 Acquisition of technological units for road maintenance
|
Name of links |
Types of technological machines |
Quantity for those. map |
Utilization factor |
Working Discharge |
The cost of cars, thousand rubles |
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|
I. Spring maintenance |
|||||||
|
Right-of-way planning link |
Motor grader DZ-31-1 |
Machinist 6r |
|||||
|
Waste collection unit |
ZIL-MMZ-555 with grab |
Water cat.C dor. slave. 2 r |
|||||
|
Ditch clearing unit |
Cuvette restorer DE-9 on DZ-31-1 ZIL-MMZ-555 with grab |
Machinist 6 r Water cat.C dor.work.2r |
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|
Pipe cleaning unit |
T-927 on KDM-130A ZIL-MMZ-555 with grab |
Water cat.C dor.work.3r |
|||||
|
Link for slope planning and grass sowing |
machinist 6r machinist 3r dor.work.2r |
||||||
|
elimination of katun the same backfilling of landing places the same layout the same seal |
ZIL-MMZ-555 |
machinist 4r water. cat.C machinist 6r machinist 5r |
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|
ED - 101 on MTZ - 50 |
machinist 4r dor.work.3r dor.work.2r |
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II. Summer content |
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|
Mower ED - 101 on MTZ - 50 |
machinist 4r dor.work.3r dor.work.2r |
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machinist 4r |
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|
machinist 5r |
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Link for marking |
machinist 5r driver's assistant 4p dor.work.3r |
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machinist 4r |
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III. autumn content |
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|
machinist 6r |
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Waste collection unit |
ZIL - MMZ - 555 with grab |
water cat.C dor.work.2r |
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|
machinist 6r |
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|
Brigade No. 1 |
dor.work.2r dor.work.1r |
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|
machinist 6r |
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|
Sand making unit |
machinist 6r driver's assistant 5p |
8 . Technological schemes for the maintenance and repair of roadsaboutgi
road verge
8.1 Technological scheme for the repair of roadsides
When backfilling lowered roadsides, work is performed in the following technological sequence:
Bringing the unit into working position;
Cutting and moving soil from reserves to the roadside;
Leveling and leveling of the poured soil;
Raising and lowering the knife;
Turns at the end of the section.
Work process schedule
Workplace organization scheme
1 - tractor T-100; 2 - trailed grader DZ-1; 3 - soil
9 . Technological schemes for the maintenance of the road in different periods of the year
9.1 Technological scheme for road maintenance in the spring
9.2 Technological scheme for road maintenance in summer
9.3 Technological scheme for road maintenance in autumn
9.4 Technological scheme for road maintenance in winter
10 . Technological description of work on the repair of the highway (repair of roadsides)
Unreinforced or non-reinforced roadsides with ruts, subsidence, puffs of extruded soil as a result of cars colliding with waterlogged soil are planned with a transverse slope of 40-60 ‰. If necessary, crushed stone is added with its subsequent planning and compaction. The trim strip is strengthened by grass sowing. On sections of roads where roadsides have large deformations and destructions, in regions with significant precipitation, especially on roads with high traffic intensity, they are usually strengthened with cohesive materials (asphalt concrete, cement concrete, black gravel, bitumen soil, etc.) . The fortification structure must comply with the current loads without the formation of unacceptable deformations on it, have an adhesion coefficient and evenness in accordance with GOST and be accepted in accordance with the requirements of the current regulatory documents.
Reinforcing layers on roadsides limit the ingress of moisture into the subgrade and, in this regard, can also be used as measures to regulate the water-thermal regime. road construction generally. When the shoulders are located above the junction of the old and backfilled part of the widening of the embankment, the decision to strengthen the shoulders should ensure the equal strength of these sections of the structure.
The most economical in terms of one-time capital costs is the strengthening of roadsides with the device of an edge fortification strip, including that performed by widening the carriageway (Fig. 16.1). The solution improves the transport and operational performance of the road, helps to strengthen the edge of the carriageway, but it is effective with a small number of roadside collisions, a small amount of precipitation and a subgrade of light soils. In conditions of intensive use of the stopping lane, in difficult soil and climatic conditions, the design of the edge fortification and stopping lanes is taken as a single one (Fig. 16.2). This design has a positive effect on the water-thermal regime of the subgrade.
10.1 Pavement on roadsides
1 - asphalt concrete, cement concrete; 2 - crushed stone materials, slags; 3 - soil reinforced with inorganic binders; 4 - crushed stone, gravel impregnated with binders; 5 - gravel (crushed stone materials); 6 - soil gravel, soil gravel materials, production waste ( brick fight, waste concrete plants, rocks of coal mines, etc.); 7 - bitumen-mineral mixtures;
8 - Bitumen primer, tar primer.
10 .2 Shoulder reinforcement solutions
I-IV - respectively, the edge fortification strip, stopping strip,
The bridging part of the curb, the carriageway of the road; 1 - layer of geomaterial;
2 - roadside reinforcement layer
11 . Technological description of work on the maintenance of dabouthorns
To create a stop, a dirt roadside is poured to the thickness of the arranged layer of soil-crushed stone base and the soil is leveled with a motor grader in 6 passes along one track.
The first two passes (rough leveling of the soil) are carried out in manual blade control mode in second gear. In this case, the capture angle ( in) is 45° (fig. 11.1), cutting angle ( b) - up to 50°, tilt angle ( G) corresponds to the cross slope of the shoulder. The dump is raised to the height of the leveled soil layer.
The third pass (final leveling and preliminary leveling with cross-sloping) is carried out in automatic blade control mode at a grip angle of 50° and a cutting angle of 41°.
For the fourth pass, the final layout of the dirt shoulder is performed.
After the fourth pass of the motor grader, the soil shoulder is compacted with a self-propelled roller on pneumatic tires for 8 passes of the roller along one track and with two final passes of the motor grader, the dirt shoulder is finally profiled to the design marks.
Prior to the construction of the base from the soil-crushed stone mixture, the soil base must be finally profiled by a motor grader in 1-2 passes along one track in accordance with the design profile, compacted with a roller on pneumatic tires in 1-2 passes along one track and accepted by the representative of the technical inspection according to the act.
The edge of the subgrade (trough), on which the subgrade will be laid, is carefully leveled with a motor grader.
Prior to the start of laying the soil-crushed stone mixture, marking work is carried out to ensure compliance with the design width of the base and the transverse slope.
11.1 Blade installation angles abgraders into working position
in- angle of capture; b- cutting angle; G- tilt angle
12. Organization of traffic and fencing of work sites
The detour zone is designed to transfer the traffic flow from the lane or lanes occupied by roadworks to free traffic lanes to bypass the work area.
The trajectory of movement in this area should be clear to drivers, therefore, with a duration of work of up to three days, such technical means as fencing devices, cones, plates, and temporary markings should be used to drive away the traffic flow. Complexes of road signs with light indication installed behind the line of cones, milestones or markings, with the help of which the traffic flow is diverted, can be installed in the run-off zone.
The length of the stripping zone (L otg) depends on the nature of the maneuver that drivers perform in this zone
Table 12.1
|
Type of maneuver |
The length of the zone of distillation - Lotg |
|
|
Rebuilding to the next lane with an infusion into the flow of cars |
Not less than L* |
|
|
Rebuilding to the next lane without pouring into the flow of cars |
Not less than 1/2 L |
|
|
Rebuilding in front of a section with alternating traffic of cars in different directions |
||
|
Switching to your lane in the traffic flow stabilization zone |
||
|
*L - the minimum length of the detour zone for the condition of rebuilding to the adjacent lane with pouring into the car tray |
When organizing traffic with the use of traffic lights, the length of the rebound zone is 5-10 m. The length of the rebound zone on a traffic lane 3.75 m wide when changing lanes to an adjacent lane with an infusion into the traffic flow (L), the number of guide devices installed in this zone in the form of cones or plates and the distance between individual devices is recommended to be taken depending on the speed of movement allowed in this zone (Table 12.2).
Table 12.2
|
Travel speed, km/h |
Length of the stripping zone, Lotg, m |
Number of cones (plates) |
Distance between cones (plates), m |
|
|
Note: - When organizing traffic with the use of traffic lights, the length of the stripping zone is 5-10 m. |
For a different lane width or the width of the closed carriageway, the length of the stripping zone is determined by the formulas:
For driving speeds up to 70 km/h
or - for speeds over 70 km/h,
where: AT - width of the closed lane or carriageway, m;
V - movement speed, km/h.
13. Occupational health and safety in the production of work
Labor protection in the production of preparatory work
According to DBN V.2.3 - 4 - 2000 "Roads", the construction of the subgrade is preceded by preparatory work associated with clearing and draining the site, rebuilding and transferring communications, installing fences and arranging access roads.
Parallel preparatory and earthworks.
Cutting down forests and shrubs on the land allotment strip for the construction of a highway should be carried out within the limits determined by the project for the production of works.
The construction organization project and the work execution project stipulate technical solutions for safe work performance at any time of the year, sanitary and hygienic services for workers, illumination of work sites and fire safety.
According to SNiP III - 4 - 80 "Safety in Construction", special warning signs of the same type are installed in all directions in the felling area at a distance of 50 m from it in all directions. Workers under the age of 18 are not allowed to fell trees.
On the cutting area where the felling of trees is carried out, it is forbidden to be by unauthorized persons.
The presence of the supervisor is mandatory. Workers involved in felling forests, removing snow from trees and preparing cutting areas for felling must be equipped with protective helmets.
When uprooting stumps, all workers must move away from the rope at a distance equal to the distance between the anchor and uprooted stumps. Only persons directly connected with its work may be near the uprooting machine.
When clearing the right-of-way from shrubs and undergrowth with a brush cutter, the zone of its work is preliminarily cleared of stones, stumps and trees, the diameter of which at the cut line exceeds 20 cm.
During the operation of the brush cutter, it is necessary to monitor the serviceability of the fence that protects the driver from being hit by cut trees and bushes.
During the operation of the machine, red flags are set on both sides of the cleared strip. Ancillary workers are not closer than 25 m to the place of work of the brush cutter.
To transfer the brush cutter to a new place, it is necessary to: raise the bow of the brush cutter to a height of at least 30 cm from the ground surface and fix it; check the reliability of attachment of the brush cutter to the tractor; make sure there are no obstructions.
Safety requirements when working on road machines
According to DBN V.2.3 - 4 - 2000 "Roads", when choosing the type of machines for the performance of work, it is necessary that the technical characteristics of the machine correspond to the parameters of the technological process and working conditions.
The machines can be used if the ambient temperature, wind speed and humidity are within the values specified in operational documentation to the car.
According to SNiP III - 4 - 80 "Safety in construction", before starting work with the use of machines, it is necessary to determine the working area of \u200b\u200bthe machine, the boundaries of the danger zone, the means of communication between the driver and the workers servicing the machine and drivers of other machines.
When using machines, special attention should be paid to ensuring that the visibility of the working area from the driver's workplace is ensured. In the event that the driver operating the machine does not have sufficient visibility or does not see the worker giving him signals, two-way radio communication is established between the driver and the worker.
The working area of the machine in the dark is illuminated by special spotlights. The levels of noise, gas pollution, vibration and dust should not exceed the established values.
Drivers of road-building machines may be persons not younger than 18 years of age who have passed a medical examination and are recognized as fit for health reasons to drive machines.
Drivers of road machines must work in overalls, safety shoes and use personal protective equipment in accordance with the nature of the work performed. The workplaces of the operator of the machine and equipment should be kept clean and provided with wiping material, cleaning equipment, which is stored in specially equipped places. There must be no foreign objects on the machine, and unauthorized persons in the working area of the machine.
Construction and road vehicles are prohibited from working at a distance of 20 m from open fuel depots.
Fuel and lubricants should be transported in vehicles equipped with special fire-fighting devices and grounding in the form of a metal circuit to remove static electricity.
The exhaust pipe must be laid forward and tilted downward to prevent sparks from reaching the tank.
If a cable, pipes or other underground communications and unknown objects are found in the developed soil, it is necessary to immediately stop work and inform the work manager.
14. Environmental protection in the course of work
14.1 Protection against atmospheric pollution by emissions and noise impacts
When performing construction work, measures should be taken to reduce atmospheric pollution by mineral dust, gas emissions from thermal installations and engines, and other equipment whose operation is associated with thermal and chemical technological processes.
Control over the state of the atmosphere outside the construction site (right of way) is carried out by nature protection services - Goskomgidromet, for populated areas - in accordance with GOST 17.2.3.01-86 .
Control over the state of the atmosphere in the working area is carried out by the production service of labor protection and safety in accordance with GOST 12.1.005-76.
Construction and road vehicles must comply with environmental and sanitary requirements:
for exhaust gas emissions - GOST 17.2.2.02-86;
according to noise - sanitary standards SN 2.2.4/2.1.8.562-96 ;
on industrial vibration - CH 2.2.4/2.1.8.566-96 .
Control over compliance with norms and requirements is carried out upon acceptance of samples of installation series of machines and is confirmed as part of certification (including for foreign-made machines).
14.2 Aquatic protection
When performing construction work on water bodies and adjacent territories, one should be guided, in addition to general SNiPs, by legal provisions, standards and norms containing special requirements for the protection aquatic environment: The Water Code of the Russian Federation (adopted on 10/18/95), Regulations on the water protection zones of water bodies and their coastal protective strips (approved by the Decree of the Government of the Russian Federation on 11/23/96), GOST 17.1.3.13-86 "Protection of Nature. Hydrosphere. General requirements for the protection of surface waters from pollution”, SanPiN 4630-88 « Sanitary regulations and norms for the protection of surface waters from pollution”.
14.3 Protection against pollution and disturbance
When designing the construction organization and performing works, it is necessary to take into account the requirements for maintaining the integrity and cleanliness of the soil and vegetation cover beyond the boundaries of the right of way, as well as minimal damage and pollution in the allotted territory not occupied by structures.
In areas for structures or excavations, the fertile soil layer should be removed and stored in specially designated areas for use in reclamation or for transfer to third-party land users.
The main reasons for the violation of the preservation of the soil layer and the decrease in soil fertility in the area affected by road construction and repair work are:
§ erosion due to the concentration of storm runoff and disturbance of the sod-vegetation cover;
§ mechanical destruction of the cover during the passage of cars and vehicles;
§ pollution by oil products, building materials and production waste.
When organizing earthworks at all stages, a timely arrangement of surface drainage should be provided, which excludes the accumulation of water in relief depressions during periods of snowmelt and heavy rains and the formation of unforeseen watercourses that wash away the soil layer. Slopes and slopes exposed during earthworks, as a rule, must be strengthened before the onset of winter in the manner provided for in the project. Design drainage devices should be carried out at the earliest possible stage of construction. Their repair at subsequent stages is easier and cheaper than the elimination of erosion and erosion centers that occur during the construction of the subgrade.
Conclusion
Based on the work done, the following conclusions can be drawn: Gusevka do not correspond to the specified technical documentation, since the smallest width of the fortified shoulder is not, as stated, 0.5 m. but in fact 0.3m, cars cannot stop on it, it follows that the norms for the safety of car traffic have been violated.
In this course project, questions on
The requirement for the operational state, admissible under the terms of ensuring road safety in accordance with GOST R 50597-93;
Requirements for the condition of the structural elements of the road section, depending on the level of maintenance in the spring-summer-autumn period;
Assessment of the transport and operational condition of the road;
Selected measures for the repair and maintenance of the road;
Determination of the order of work on the repair and maintenance of the highway,
Also done technological description work on the repair and maintenance of the highway, the organization of traffic and the fencing of work sites are considered. Occupational health, safety and environmental protection are described.
Bibliography
1. Babkov V.F., Andreev O.V. Road design. Part 1. - M.: Transport, 1987. - 368 p.
2. Planning of road repair work based on forecasting the transport and operational state of highways: Method, instructions / Sh.Kh.
Bekbulatov, O.A. Krasikov and others; Ministry of Construction Rep. Kazakhstan. - Alma-Ata, 1993. - 36 p.
3. GOST R 50597-93. Highways and streets. Requirements for the operational state, admissible under the terms of ensuring road safety.
4. GOST 23457-86. Technical means traffic organization. Application rules. - Instead of GOST 23457-79;
5.http://www.gosthelp.ru/text/SpravochnikSpravochnayaen2.html
6.http://ohranatruda.ru/ot_biblio/normativ/data_normativ/51/51537/index.php#i2458890
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GOST R 52399-2005
Group T52
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
GEOMETRIC ELEMENTS OF ROADS
Geometric elements of automobile roads
OKS 43.080
OKP 48 0000
Introduction date 2006-05-01
Foreword
The goals and principles of standardization in the Russian Federation are established by the Federal Law of December 27, 2002 N 184-FZ "On Technical Regulation", and the rules for the application of national standards of the Russian Federation - GOST R 1.0-2004 * "Standardization in the Russian Federation. Basic provisions"
_______________
GOST R 1.0-2012. - Database manufacturer's note.
About the standard
1 DEVELOPED by the Moscow Automobile and Road Institute (State technical university), Russian Academy transport, LLC "Engineeringinvest"
2 INTRODUCED by the Technical Committee for Standardization TC 418 "Road Facilities"
3 APPROVED AND PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated November 22, 2005 N 297-st
4 INTRODUCED FOR THE FIRST TIME
Information about changes to this standard is published in the annually published information index "National Standards", and the text of changes and amendments - in the monthly published information indexes "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly published information indexes "National Standards". Relevant information, notification and texts are also placed in information system general use - on the official website of the national body of the Russian Federation for standardization on the Internet
1 area of use
1 area of use
This standard applies to the design of newly built and reconstructed public roads (hereinafter referred to as highways).
This standard does not apply to the design of temporary roads for various purposes(constructed for a service life of less than 5 years), on-farm roads, city streets and winter roads.
2 Normative references
This standard uses references to the following standards:
GOST R 52398-2005 Classification of highways. Basic parameters and requirements
GOST 23457-86 * Technical means of traffic management. Application rules
_______________
* The document is not valid on the territory of the Russian Federation. GOST R 52289-2004 applies, hereinafter in the text. - Database manufacturer's note.
Note - When using this standard, it is advisable to check the effect of reference standards according to the "National Standards" index, compiled as of January 1 of the current year, and according to the corresponding information indexes published in current year. If the reference standard is replaced (modified), then when using this standard, you should be guided by the replaced (modified) standard. If the referenced standard is canceled without replacement, the provision in which the reference to it is given applies to the extent that this reference is not affected.
3 Terms and definitions
In this standard, the following terms are used with their respective definitions:
3.1 edge band: A shoulder strip designed to protect against the destruction of the edge of the carriageway and allowing regular arrivals of vehicles on it.
3.2 security lane: A specially prepared section of the roadway adjacent to the border of the carriageway, which allows regular arrivals of vehicles to avoid accidents.
3.3 reinforced part of the road shoulder: The part of the roadside that has pavement.
3.4 dirt part of the road shoulder: The part of the shoulder that does not have pavement.
3.5 parking lane: Fortified part the surface of the subgrade, intended for stopping and parking vehicles on it, marked with special road signs.
3.6 roadway: The main element of the road, intended for the direct movement of vehicles.
4 Geometric elements of the plan and longitudinal profile of the road
4.1 The largest longitudinal slopes and the smallest visibility distances, depending on the design speed, are given in Table 1.
Table 1 - Largest longitudinal slopes and shortest visibility distances
Estimated speed, km/h | The largest longitudinal slope, ‰ | The smallest visibility distance, m |
|
to stop | oncoming car |
||
Notes |
|||
4.2 In all cases where, according to local conditions, the regular appearance of people and animals on the road is possible, it is necessary to provide side visibility of the lane adjacent to the road, separated from the edge of the subgrade for roads designed for a design speed of 100 km/h and above at a distance of 25 m, for other roads - 15 m.
4.3 Long slopes are allowed on roads in mountainous areas. The length of a section with a prolonged slope in a mountainous area is determined depending on the magnitude of the slope, but not more than the values \u200b\u200bgiven in Table 2. With longer prolonged slopes, it is necessary to include in the longitudinal profile sections with reduced longitudinal slopes (no more than 20‰), as well as sites to stop cars with distances between them not exceeding the lengths of the sections indicated in table 2.
Table 2 - Length of sections with reduced longitudinal slopes
terrain | Longitudinal slope, ‰ |
|||||
Maximum length of a section with a long slope, m |
||||||
Flat and slightly hilly | ||||||
heavily crossed | ||||||
4.4 The dimensions of the areas for stopping cars on long slopes must ensure the placement of the estimated number (but not less than 3) trucks. Their location is chosen from the safety conditions of the parking lot, the exclusion of the possibility of talus, rockfalls and, as a rule, near water sources.
4.5 On long descents with slopes of more than 50‰, emergency exits are provided, which are arranged in front of curves of small radii located at the end of the descent, as well as on straight sections of the descent every 0.8-1.0 km on the right side along the vehicle.
5 Elements of the cross profile of the road
5.1 The main parameters of the elements of the transverse profile of the carriageway and subgrade of roads, depending on their category according to GOST R 52398, should be taken from Table 3.
Table 3 - Parameters of the elements of the cross profile of the carriageway and subgrade of highways
Road element parameters | Automatic | Highway | Motor roads of ordinary type (low-speed road) categories |
|||||
Total number of traffic lanes, pcs | 4 or more | 4 or more | 4 or more | |||||
Lane width, m | ||||||||
Shoulder width, m | ||||||||
Width of the edge strip at the curb, m | ||||||||
The width of the reinforced part of the curb, m | ||||||||
The smallest width of the central dividing strip without road barriers, m | ||||||||
The smallest width of the central dividing strip with a fence along the axis of the road, m | 2 m + fence width | |||||||
Width of the marginal security strip at the dividing strip, m | ||||||||
Notes |
||||||||
5.2 The transverse profiles of highways should correspond to the profiles shown in Figures 1-12.
Dimensions in meters
PB - edge strip at the dividing strip, - width of the dividing strip, - width of the fence, taking into account the requirements of GOST 23457
Figure 1 - Cross profiles of highways of categories IA, IB, IB with guardrails
Dimensions in meters
Figure 2 - Cross sections of highways of categories IA, IB without barriers
Dimensions in meters
PB - edge strip at the dividing strip, FC - carriageway, KP - edge strip at the curb, RP - dividing strip
Figure 3 - Cross profiles of IB category roads without barriers
Dimensions in meters
GOST 23457
Figure 4 - Cross sections of highways of category II with guardrails with four traffic lanes
Dimensions in meters
PB - edge strip at the dividing strip, FC - carriageway, KP - edge strip at the curb, RP - dividing strip
Figure 5 - Cross profiles of motor roads of category II without guardrails with four traffic lanes
Dimensions in meters
GOST 23457
Figure 6 - Cross profiles of motor roads of category II with barriers with two traffic lanes
Dimensions in meters
FC - carriageway, CP - edge strip at the curb
Figure 7 - Cross sections of motor roads of category II without barriers with two traffic lanes
Dimensions in meters
FC - the carriageway, KP - the edge strip at the curb, - the width of the fence, taking into account the requirements of GOST 23457
Figure 8 - Cross sections of motor roads of category III with barriers
Dimensions in meters
FC - carriageway, CP - edge strip at the curb
Figure 9 - Cross sections of motor roads of category III without barriers
Dimensions in meters
FC - the carriageway, KP - the edge strip at the curb, - the width of the fence, taking into account the requirements of GOST 23457
Figure 10 - Cross sections of motor roads of category IV with barriers
Dimensions in meters
FC - carriageway, CP - edge strip at the curb
Figure 11 - Cross sections of motor roads of category IV without barriers
Dimensions in meters
OB - roadside, FC - carriageway
Figure 12 - Cross profiles of category V roads
5.3 The edge strips at the shoulders and the safety strips on the median strip must have pavement of the same strength as the carriageway.
5.4 The reinforced part of the shoulder outside the edge strip on the roads of categories I-IV must have pavement coated with stone material treated with a binder. The strength of the pavement should be sufficient to prevent residual deformations from a stationary vehicle with a calculated axle load.
5.5 Roadsides are intended for temporary placement of vehicles that are out of order or damaged in traffic accidents. For stops and parking of vehicles, parking lanes should be provided on the surface of the subgrade, separated from the roadway by fences or a dividing island, or areas for stops and parking of vehicles outside the subgrade. The distance between parking lanes and parking areas should be assigned in accordance with design standards.
5.6 The width of the transitional speed lanes should be taken equal to the width of the lanes of the main carriageway.
5.7 The width of roadsides of motor roads in places where transitional speed lanes and additional lanes for lifting for roads of categories IA, IB, IB can be reduced to 1.5 m, for roads of other categories - up to 1.0 m. The unpaved part of such roadsides should be 0.50-0.85 m depending on the rigidity of the fences; the rest of the shoulder should be reinforced according to the grade of the road.
5.8 When arranging additional lanes for lifting, their width should be taken equal to the width of the lane of the main carriageway.
5.10 The width of the dividing strip on sections of roads laid on valuable land, on particularly difficult sections of roads in mountainous areas, on large bridges, as well as when laying roads in built-up areas and in other justified cases, may be reduced to a width equal to the width of the strip for installing fences plus 1 m on each side.
Electronic text of the document
prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2006
In the process of road reconstruction, in many cases, roadsides are rebuilt or re-fortified, destroyed slopes of embankments and cuts are restored and strengthened.
Strengthening the shoulders significantly affects the safety and speed of vehicles, as it prevents dust and dirt from entering the roadway, creates conditions for a safe exit to the side of the road if necessary.
This is especially important in the autumn-spring periods of the year. Reinforced shoulders provide waterproofing of the subgrade, increasing its strength and stability, and preventing the destruction of the surface of the shoulders when hit by vehicles. AT winter time Reinforced shoulders help transport snow during blizzards and make it easier to remove during snow clearing.
Pairing the pavement directly with the dirt shoulder is unfavorable for the operation of the road. The water flowing down from the carriageway softens the dirt shoulder, which is often rutted, and flows in the direction of the longitudinal slope along the edge of the pavement.
Water erodes the soil along the edge of the pavement, washes away the pavement and penetrates into the base. The strength of the pavement is reduced, the passage of cars along the weakened lane leads to the formation of cracks in the pavement and breaking off of its edges.
In addition, the soil from the curb is carried by the wheels onto the pavement, its edge becomes poorly distinguishable from the curb, and drivers, trying to stay away from the edge, drive to the middle of the carriageway, which leads to the actual narrowing of the carriageway and increases the risk of traffic accidents.
Under these conditions, the widening of the carriageway by 0.5-1.0 m is also ineffective. Therefore, it is necessary to strengthen the shoulders, especially along the edge of the pavement.
Strengthening roadsides, especially those made of loamy soil, and laying edge strips on them significantly increase traffic safety. When it rains, accidental wheeling of the vehicle on the side of the road can lead to an accident.
The edge stripes clearly indicate the boundaries of the roadway and give drivers confidence that they will not fall into the soggy soil of the shoulders. This allows them to travel faster.
In the presence of a border strip and a reinforced shoulder throughput two-lane road carriageway increases by 15-30%.
In addition, the edge stripes give the road a finished look and feel. beautiful decoration. In accordance with SNiP 2.05.02-85, coatings on edge reinforced strips and on roadsides must differ in color and appearance from roadway coatings or be separated by markings. The roadsides must be strong enough to allow vehicles to ride on them.
To ensure traffic safety, the coefficient of adhesion of a coated wheel on the side of the road should not differ by more than 0.15 from the coefficient of adhesion on the carriageway.
To protect roadsides and slopes of the subgrade from erosion on road sections with longitudinal slopes of more than 30‰, with embankments more than 4 m high, in places of concave curves in the longitudinal profile, longitudinal trays and other structures are installed to collect and drain water flowing from the carriageway.
Dividing lanes on roads of category I are connected with the carriageway by arranging reinforced lanes on the dividing strip. The rest of the dividing strip is strengthened by sowing grasses or planting shrubs located at a distance of at least 1.75 m from the edge of the carriageway.
The edge strips can be made from 6 cm thick prefabricated white concrete slabs on normal cast-in-situ concrete; from monolithic concrete thickness 20-22cm; from asphalt concrete laid simultaneously with the pavement of the roadway on the same type of base. In this case, the edge strip is separated from the main coating by a marking line.
The minimum necessary is the strengthening of roadsides by the device of the edge reinforcement strip, including that performed by widening the carriageway. This improves the transport and operational performance of the road, helps to strengthen the edge of the carriageway, however, it is effective with a small number of roadside collisions, a small amount of precipitation and a subgrade of light soils.
In conditions of intensive use of the stopping strip, in difficult soil and climatic conditions, the design of the edge fortification and stopping strips can be taken as a single one (Fig. 57).
This design has a positive effect on the water-thermal regime of the subgrade.
The use of geosynthetic materials in structures is dictated by the need for waterproofing, additional drainage or reduction in the consumption of road construction materials by increasing the strength of the structure.
If it is necessary to strengthen the road structure in the reinforcement layers or under them, reinforcing materials, including geogrid, geoweb, etc., are laid in contact with the drainage layer.
Rice. 57. Solutions for strengthening roadsides: I-IV - respectively, the edge fortification strip, stopping strip, bridging part of the roadside, carriageway; 1 - layer of geomaterial; 2 - a layer of curb reinforcement.
This solution is useful for:
When reorganizing the drainage layer in the area of roadsides with filling a layer of fine sands with K f = 1-2 m/day;
With a silted drainage layer and strengthening of the roadside without its reconstruction;
As a measure that reduces the moisture content of subgrade soils in the 2nd and 3rd types of terrain according to the conditions of moisture in the II and III road-climatic zones (roads of categories I-III) and as an activity in regulating the water-thermal regime of the subgrade in areas , prone to the formation of abysses, to accelerate the removal of water;
When laying a crushed stone layer directly on the ground at their contact.
When laying edge concrete slabs along existing coverage perform the following operations:
They arrange a ditch for the edge strip on the side of the road;
Align the edges of the old coating, usually having bumps, sagging, etc.;
Align the base with the distribution of the leveling material;
Lay and compact a layer of cement concrete mixture;
Lay white concrete slabs with careful adjustment to the edge of the coating and pouring cement mortar for leveling; sprinkle soil from the side of the roadside and compact it;
Fill transverse and longitudinal seams with bitumen, bituminous mastic or cement mortar;
Organize the care of the edge strips to avoid the arrival of cars on them until the concrete has completely hardened.
Plates are used with a width of 0.75 and a thickness of 0.2 m. Two-layer slabs are recommended - the lower layer is made of ordinary concrete, and the upper one is made of white or colored concrete. However, as experience shows, at dark asphalt concrete pavements slabs of ordinary concrete also look quite contrasting. A disadvantage of concrete slab edge strips, especially those prepared in steam plants, is that the concrete of the surface layer begins to flake relatively soon and the slabs then collapse.
If it is difficult to obtain ready-made cement concrete slabs, it is more economical to install cast-in-situ concrete edge strips in situ prior to the construction of the pavement.
Ticket number 15.
Question 1. Crushed stone-sand mixture (SCHPS) is a combined building material of natural origin and consisting of a mixture of crushed stone and sand. This mixture is formed naturally during the weathering of rocks or during industrial crushing of rocks in quarries.
Classification
Shchps C1 0-40. Mixes of fraction 0-40 are intended for the construction of road foundations with an appropriate feasibility study.
Shchps C2 0-20. Sieving from zero to twenty millimeters, like C1 is intended for road construction different type.
Shchps C3 0-120. A material with large fractions used for the construction of additional layers of the bases of the roadway.
Shchps C4 0-80. Use the strengthening of roadsides. It is one of the two most demanded types of inert material.
Shchps C5 0-40. As well as a fraction from 0 to 80 millimeters, they are used to strengthen roadsides. A popular mixture in the construction of all types of tracks.
Shchps C6 0-20. Material from crushed stone and squeak, for the construction of the bases of the roadway.
Shchps C7 0-10. In this case, crushed stone of a fraction from 0 to 10 mm is used, which is great for arranging the base.
Shchps C8 0-5. Used for road foundations, which includes crushed stone or crushed screenings of not more than 5 mm.
Shchps C9 0-80. Suitable for roadsides and bases, consists of crushed stone up to 80 mm in size and sand
Shchps C10 0-40. Material from the average fraction of stone and sand. It is used at the initial stage of road works.
Shchps C11 0-20. Crushed stone-sand material serves to strengthen the canvas and build the necessary stages.
C4-C11 - for the device of additional layers of bases;
C4-C6 and C9-C10 - to strengthen roadsides;
С12-С13 - mixtures for cutting.
rubble requirement
1.1.5.2 The filtration coefficient of crushed stone-sand mixtures for additional layers should be at least 1 m / day.
1.1.5.3 Finished crushed stone-sand mixtures in terms of grain composition, plasticity, water resistance, content of dust particles (less than 0.05 mm in size), filtration coefficient, degree of heaving and in terms of the specific effective activity of natural radionuclides must comply with GOST 25607.
1.1.5.4 Crushed stone and sand included in the composition ready mixes, must comply with the requirements specified in paragraphs. 1.1.2, 1.1.3 of these technical conditions.
1.1.5.5 Crushed stone-sand mixtures should not contain fragments and scraps of steel reinforcement.
1.1.2.1 Crushed stone in terms of grain composition, strength, frost resistance, content of lamellar (flaky) and needle-shaped grains, dust particles, stability of the crushed stone structure against all types of decay and in terms of the specific effective activity of natural radionuclides must comply with the requirements of GOST 8267.
The crushing grade of crushed stone should not be lower than 400.
1.1.2.2 Crushed stone in terms of plasticity and water resistance must comply with the requirements of GOST 25607.
1.1.2.3 The grade of crushed stone in terms of abrasion must be in accordance with GOST 8267.
1.1.2.4 The grade of crushed stone in terms of frost resistance should not be lower than P25.
1.1.2.5 The density of crushed stone grains must be at least 2.0 g/cm 3 .
1.1.2.6 Crushed stone should not contain fragments and scraps of steel reinforcement.
1.1.2.7 Bulk bulk density of crushed stone is determined by the manufacturer in each batch.
Sand Requirements
1.1.3.1 Depending on the grain composition, sand is divided into groups according to size:
I class - very large, increased size, large, medium and small;
· Class II - very large, oversized, large, medium, small, very small, thin and very thin.
1.1.3.2 Sand in terms of grain composition, fineness modulus, content of dust-like and clay particles, as well as clay in lumps, strength and value of specific effective natural radionuclides must comply with the requirements of GOST 8736.
1.1.3.3 The filtration coefficient of sand from crushing screenings for additional layers should be at least: 1 m/day, - for drainage layers of highway bases; 0.2 m/day - for frost-protective layers of the bases of highways.
1.1.3.4 For frost-protective layers of bases, non-rocky and slightly foamy sands from crushing screenings should be used. The degree of heaving is characterized by the relative deformation of frost heaving, which should be no more than 0.04.
1.1.4 Weight loss during calcination in crushed stone and sand should be no more than 20%.
Question 2. Elements of the transverse profile of roads. Options for broadening the overall dimensions of bridge structures.
cross profile a scaled-down image is called a section of the road by a vertical plane that is perpendicular to the axis of the road
Elements of the cross profile of the road: 1 - slope of the subgrade; 2 - strengthening the slope of the subgrade by sowing grasses; 3 - curb; 4 - edge of the carriageway; 5 - base of the embankment; 6 - roadway; 7 - axis of the transverse profile; 8 - layers of pavement; 9 - the body of the embankment; 10 - reinforced roadside; 11 - edge of the subgrade; 12 - laying the slope; 13 - cuvette
Options for broadening the overall dimensions of bridge structures.
Method for broadening a bridge structure using a cable-stayed system
Widening of bridge structures using steel ropes
Question 3. The width of the carriageway and shoulders. Edge bands. Organization of the construction site during the construction of bridge structures.
The width of the carriageway is an important factor that determines the speed of the road and its capacity.
With a divided carriageway consisting of two or more lanes for traffic in one direction, the width of each individual lane is not as decisive as for a carriageway without a dividing lane.
Each lane is wide enough for one row of cars. On roads of categories I and II, the width of each lane must be at least 3.75 m, on roads of category III - 3.5 m and on roads of category IV - 3 m. seeking to expand. The difference in lane width of 0.5 m is essential for the speed of overtaking and passing cars. With a lane width of 3 m, drivers of oncoming vehicles tend to snuggle up to the right side of the road, but it is safe to make such a passing only at low speed, otherwise there is a danger of going to the side of the road. And since on the roads of the lower categories the shoulder does not have an improved surface, this can lead to a side skid of the car.
Edge bands. The ability to stay on the right side of the road when driving at high speeds is essential to maintaining safety conditions. This task is facilitated when the road has edge strips separating the carriageway from the curb. For newly built roads, this is a mandatory element, and for roads of categories I and II, the width of the edge strip should be 0.75 m, and for other paved roads - 0.3 ... 0.5 m. On highways they are usually laid out from white concrete slabs, on other roads from various stone materials, such as cobblestone, and painted with some kind of contrasting paint.
The main value of the edge strips is that they prevent accidental derailment of the wheels of one side of the car on the side of the road. Such a seemingly minor violation in driving often leads to serious consequences. If the curb surface is a natural, unreinforced soil, then the wheels of one side of the car come down on it at high speed, leading to a side skid.
Construction site- a fenced area used to accommodate a construction site under construction, temporary buildings and structures, equipment, soil dumps, storage of building materials, products, equipment and construction work.
The construction site of the preparatory period (during the construction of the bridge) differs from the construction site during the installation of superstructures. This is due to the staged development of the construction site. At the stage of the preparatory period, temporary roads and buildings are built, which will serve during the entire process of the construction of the bridge. Then, as the building develops, the rest of the buildings and roads are erected.
Unlike construction industrial buildings and structures, the general plan of which is focused on their further operation. The construction site for the construction of the bridge is fixed in advance by the route of the road being laid, and its choice comes down to assigning places on both banks that are optimal for locating temporary roads, warehouses, etc. All premises and warehouses must be located in flood-free places.
The construction site for the construction of a large bridge can be located on one and both banks, on both banks and on an island. If there are several platforms, one of them will be the main one, and the rest will be auxiliary. During the construction of a large bridge at a great distance from the bases and in uninhabited areas, a construction site is designed with a residential town and a testing ground for the manufacture of structures.
The creation of a construction site on one of the banks is widely practiced in the construction of medium-sized bridges across non-navigable or low-navigable rivers. At the same time, the construction site is made small. Place on it mainly access roads, warehouses of prefabricated structures.