City Street Design
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Design of the city street. The project includes: 1. Explanatory note Drawings: 2. Plan 3. Longitudinal profile, transverse profile 4. Vertical layout 5. Volume of excavation by cartogram method
Job Sheets for Coursework
1. General characteristics of road design area
Climatic characteristics of road design area
Soil and geological structure of the area
Road construction materials
2. Justification of technical standards of the designed road
3. Determination of technical characteristics of the designed streets
4. Designing the cross profiles of the main and intersecting streets, determining the width of streets in the "red lines"
5. Design plan and longitudinal profile of main and intersecting streets
5.1 Street Plan Design
5.2Projection of longitudinal profile of streets
6. Development of vertical intersection layout
7. Determination of the volume of excavation at the intersection by the method of "cartograms"
8. Purpose and calculation of roadway structure
8.1 Determination of intensity of impacts on road clothing
8.2 Calculation of road clothing for frost resistance
8.3 Calculation of required draining layer thickness
8.4 Check by calculation of coating layer thickness and base
8.5 Check by calculation of asphalt concrete pavement thickness
List of sources used
In this course project, a section of the city road of main district significance was designed. The project is designed in accordance with the design assignment. The development of the project was carried out on the basis of existing standard catalogs, as well as taking into account the requirements of the SP, GOST, VSN, ODN and design standards. The project consists of an explanatory note and a graphic part on 2 sheets of A1 format, 1 sheet of A0 format and 1 sheet of 4A0 format. The note is made on 41 pages and contains 7 tables, 2 figures, 36 formulas, 15 titles of literature.
General characteristics of road design area
1.1. Climatic characteristics of road design area
The climate of Volgograd is described as a temperate continental location of the city in the southeastern part of the Russian Plain, mainly in the steppe zone and significant distance from the seas and oceans.
The climate of the region is formed under the influence of circulation processes of the southern zone of temperate latitudes.
The main climatic features of the Volgograd region are formed under the influence of the Asian mainland, supercooled in winter and superheated in summer, as well as under the mitigating influence of the western transfer of air masses. The continental nature of the climate of the region is manifested in sharp fluctuations in temperature (from severe winters to hot summers), lack of precipitation, often repeated droughts and explains the predominance of anticyclonic circulation over cyclic.
The average annual air temperature varies from 5.5 ° to 8.5 ° C, decreasing from the southwest to the northeast of the region.
The absolute minimum air temperature is 3642 ° C frost and is observed in January Fevral, the absolute maximum is 4244 ° C heat and is usually observed in July-August.
Annual rainfall ranges from an average of 270 to 450 mm, decreasing from northwest to south-east, where there is a lack of moisture. The largest amount of precipitation falls in June and December (40.3 and 40.3 mm per month, respectively), the smallest in March (27.4 mm).
The depth of freezing of the soil is different and depends on the geographical location. The average freezing depth for Volgograd and the Volgograd region is 1.0 m for clays and loam, 1.1 for sands and sandy loam.
The average long-term period of formation of a stable snow cover in the northern regions is December 1117, in the southern regions - December 2025. Snow cover lasts from 90 to 110 days. The average height of the snow cover ranges from 13 to 22 cm.
The city of Volgograd is located in the fourth road-climatic zone.
Characteristic of movement of air masses by speed and repeatability is presented in the form of wind rose (sheet 1 of graphic part).
The road-climatic graph is presented in the graphic part (sheet 1).
We assign construction periods based on the specifics of the work and dependence on air temperature. Work on the construction of artificial structures is carried out at 0 ° C in spring and we finish at 0 ° C in the autumn period (sheet 1 graph. parts, period I). Period I is 236 days.
The erection of the roadbed begins at + 5 ° C in the spring and ends until a crust of frozen soil forms about 10 cm in autumn, which corresponds to the end of November according to long-term data (sheet 1 graph. parts, period II). Period II is 236 days .
We carry out the construction of non-rigid road clothing at + 5 ° C from spring and finish two weeks before the rainy period or at + 10 ° C in autumn (sheet 1 graph. parts, period III). Period III is 183 days. During surface treatment of the coating, the construction of road clothing ends at + 15 ° С.
Volgograd is located on the Volga Upland, gradually decreasing to the south, its slope facing the Volga, short and steep, is divided by beams and ravines into hills. To the south stretched the flat elevation of Ergeni with a steep eastern and gentle western slopes, passing in the west into the Don Plain. To the south of Volgograd (Krasnoarmeysky district), the Sarpinsky lowland occupies the space between the Volga and the Ergens.
The watershed is a hilly plain. The eastern slopes of the watershed pass into floodplain terraces, on which, in fact, the city is located. The first terrace rises above the lower level of the Volga at 2530 m. And separated from it by a steep cliff. It houses the central part of the city, most of the Kirov and Krasnoarmeysky districts, as well as the territory of OJSC TPR VgTZ, FSU PO Barricades and OJSC Metallurgical Plant Red October.
The second terrace rises above the first by 1520 m. On it is located most of the city. In the south, these terraces decline and pass into the Sarpin lowland.
1.3. Soil geologic structure of the area
Based on the assignment for design, the soil geologic structure of the area is represented by three sediments. The lower layer is sand with a capacity of 1.5 m at elevated and 1.0 m at reduced areas. Above is a layer of loam not dusty with an average power of 1.0 m. The upper layer is represented by sandy loam with an undusty power of 2.35 m at elevated and 2.8 m at lowered sections. And vegetal soil 0.15 m thick on elevated and 0.2 m in reduced areas.
1.4. Hydrological conditions
According to the map, there are no wetlands and places with permanent watercourses. There are places for lowering the relief in which meltwater and stormwater will accumulate.
Based on the design assignment, the depth of groundwater ranges from 4.0 to 4.5 m.
1.5. Road construction materials
The city of Volgograd is provided with local road construction materials necessary for the construction of a highway. The city has sand, crushed stone of various fractions and grades, cement, asphalt concrete and bitumen of various grades.
Designing the cross profiles of the main and intersecting streets, determining the width of streets in the "red lines"
Projected streets of regional trunk significance (Zelenaya St. and Yellow St.) are located on the built-up territory. The specified transverse slopes of the carriageway, technical strip and sidewalks in paragraph 3 of the explanatory note provide a watershed .
The adopted width of the carriageway of the street guarantees a given intensity with a perspective of 20 years. Engineering networks in the form of:
communication and lighting cables;
low and medium pressure gas pipeline.
On the border of the roadway, sidewalks and technical strip, side stones are installed to provide water flow and not destroy the edges of the roadway.
Lighting in the form of lampposts provides traffic safety in the dark on the roadway and safety on the sidewalks.
The width of the sidewalks is accepted according to the intensity of pedestrians on it.
In accordance with the technical standards adopted in paragraph 3 and the purpose of the designed streets, the dimensions of the elements of the transverse profiles are determined. Typical cross-sectional street profiles are shown in [3, Table 19].
The cross profile of the main and intersecting streets is shown in 2 sheets of the graphic part of the course design.
5.2 Design of longitudinal profile of streets
In the course project for the construction of the vertical layout of the intersection of the main and intersected streets, the method of "design contours" was adopted, which is discussed in paragraph 6. This method allows you to depict the terrain of a street, intersection, etc. without preliminary development of a longitudinal profile using a plan. Since students do not have experience with the method of "design contours," in a course project it is first necessary to build a longitudinal profile of the projected streets and develop a vertical layout project based on it.
The design line with a gable cross profile is designed along the axis or along trays or ditches of the carriageway, with a single gable - along the inner edge. The design step (distance between profile fractures) is 50 m. The control points are the beginning and end of the projected streets, as well as the place of their intersection. When designing the longitudinal profile, it is necessary to minimize the volume of earthworks. Technical standards for the main and intersected streets are given in paragraph 3.
If in terms of the terrain of the urban territory it is technically possible and economically feasible, then the following parameters of vertical curves are adopted:
- radius of convex curves - 20,000 m, length - 300 m;
- radius of concave curves - 8000 m, length - 100 m.
The minimum and maximum values of longitudinal slopes depending on the type of pavement and the category of streets and roads are given in [3, Table 32, 33].
Soil-geological and hydrological conditions of the street design area belong to the category of favorable. Groundwater lies at a significant depth and does not affect the roadway.
The design of longitudinal profiles begins with the identification of control points, which are:
intersections with other streets;
start and end street elevations.
The elevation of the control points allows you to map the black design line on the longitudinal profile. At the same time, taking into account the situation of the terrain, soil conditions, hydrological conditions along the route, as well as considerations on possible methods of performing work on individual sections.
After choosing the optimal option, we carry out a thorough study, refining the position of the design line, its final application to the longitudinal profile of the street.
The accepted position of the design line at the intersection of ul. Bulgakov and Mayakovsky St. provides an optimal intersection with an elevation of 0.10 m.
Longitudinal profiles of the main and intersecting streets are presented in 2 graphic parts of the project .