А. А. Быкова, Т. В. Мордовцева, Я. А. Быкова

LECTURE COURSE ON RECONSTRUCTION TECHNOLOGY OF ROADS AND STREETS

Учебное пособие

Воронеж 2020

МИНИСТЕРСТВО НАУКИ И ВЫСШЕГО ОБРАЗОВАНИЯ РОССИЙСКОЙ ФЕДЕРАЦИИ

Федеральное государственное бюджетное образовательное учреждение высшего образования

«Воронежский государственный технический университет»

А. А. Быкова, Т. В. Мордовцева, Я. А. Быкова

LECTURE COURSE ON RECONSTRUCTION TECHNOLOGY OF ROADS AND STREETS

Учебное пособие

Воронеж 2020

ВВЕДЕНИЕ

В настоящее время проблема реконструкции автомобильных дорог и городских улиц становится все более и более актуальной.

Чтение лекций по дисциплине способствует получению знаний магистрантами по теоретическим основам, оказывает помощь в овладении методами современной дорожной науки, дает возможность рассмотреть практическое применение различных способов при реконструкции автомобильных дорог и городских улиц в современных условиях.

Дисциплина «Технология реконструкции автомобильных дорог и городских улиц» направлена на развитие у магистрантов инженерного мышления и широкого инженерного кругозора, чему способствует системное рассмотрение взаимосвязанных вопросов изысканий, проектирования, технологии и организации реконструкции автомобильных дорог и городских улиц в увязке с экономикой, природно-климатическими и другими факторами района расположения транспортного сооружения.

Совершенствование вузовской языковой подготовки по инженернотехническим, специальностям – одно из направлений модернизации высшего образования, В отношении неязыковых специальностей и направлений подготовки, ведущую роль играют общественные потребности, связанные с необходимостью использования иностранного языка специалистом в определенных ситуациях.

Современный инженер должен быть специалистом высокого класса, владеть английским языком на уровне, позволяющем не только читать профессиональную иностранную литературу, но и владеть практическими навыками общения

UNIT 1

PRINCIPLES OF ROAD RECONSTRUCTION OPERATIONS ASSIGNMENT

1.1.Conception of reconstruction, work classification on road improving.

1.2.Assessment of road state and measures for road reconstruction.

1.1.According to the road – repair works classification the measures for improving operation road state improving are divided into three kinds: maintenance, repair and reconstruction.

Road repair is the complex of works for improving traffic-operational

characteristics of roads and road structures, that is restoration of wear of road surface, its evenness improving and its adhesive properties increasing, strengthening of road base and road bed, restoration of wear out road structures and road components of road structures or their replacement by the most strength and economic, also

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organizational and safe works at the result of which the required traffic conditions are supplied or rehabilitated. While repairing only road temporary parameters and characteristics without change of constant parameters and characteristics (carriageway and roadbed width, radiuses of curves in plan and profile. longitudinal slops etc.) are reconstructed.

Road reconstruction is a complex of measures for improving technical road category due to the improving road traffic – operational characteristics.

Reconstruction is applied in the cases when traffic intensity on the existing road increases in 1,5 times and more in comparison with design one for the given category and its following increasing is expected.

Continuity, speed, comfort, traffic safety, road capacity and loading level; permissible overall dimensions; vehicle axial load and total mass; ecological, esthetic and others characteristics are road transport-operational performances.

1.2. The level of improvement of the main road characteristics depends on the complex of measures provided by the reconstruction project. The set of measures are determined according to the diagnostic and assessment of actual road state.

Diagnostic is the observation, collection and analysis of information about the geometrical and technical characteristics and parameters, physical properties of road structures.

Due to the materials diagnostics road structures and condition are estimated.

Assessment of traffic – operational condition is the definition of the level of actual road condition and road structures correspondence to the requirements.

There are some methods of road condition assessment:

1)Method of comparison of technical parameters and characteristics;

2)Method of comparison according to both technical and traffic-operational properties;

3)Method of comparison of users’ demands.

The sense of the condition assessment by the first method is the comparison of these parameters actual values and characteristics with normative required and designed ones.

Simplicity of assessment and determination of repair works or reconstruction measures is the advantage of this method.

But there are some shortcomings:

–a great number of assessed road characteristics and parameters which hesitate from 10 up to 40 and more in dependence of different methods. Wherein the assessments have different quantitative and qualitative values on every section.

–combined methods of assessment of traffic-operational road condition includes the assessment of the road according to the main traffic-operational indexes and technical parameters and characteristic.

–method of assessment is rather simple: there are determined real values of traffic-operational indexes and technical characteristics in their absolute or relative forms they are compared with standard requirements due to every parameter and

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characteristic and then the assessment (disagreements) with account of which the measures for repair and reconstruction are prescribed.

Combined assessment system of road state characteristics includes the following characteristics:

1.Traffic speed is assessed due to the value of coefficient of design speed providing at transitional periods of the year;

2.Road traffic carrying capacity and road traffic load level;

3.Traffic safety is assessed by three characteristics: accident coefficient, accident rate coefficient and safety coefficient;

4.Coincidence of actual geometrical characteristics to normative ones for the given road category. Assessed by simple comparison;

5.Road bed durability is assessed by the strength factor;

6.Surface evenness is assessed by the coefficient of evenness;

7.Roughness and adhesion properties of the surface is assessed by index of slipperiness and adhesion coefficient in surface length.

Except the main characteristics of technical and physical ones there is assessed the conditions of the roadsides, slops, drainage systems. Bridges state is mainly assessed by definition of carrying capacity.

Advantages – the road simultaneously assessed due to the technical

characteristics and consumers’ requirements.

Disadvantages – every index, parameter and characteristic is assessed differently and has their own normative requirements. As a result according to the assessment results there is received 80 numerical data in absolute or relative form showing deviations or coincidences with normative requirements on every road section and therefore definition and choice of measures for road repair and reconstruction.

The methodology of complex assessment of road quality and state according to the main users’ requirements is based on the fact that in market conditions the finite task of road operation is their provision with high consumers' properties.

Road consumer properties are the collection of technical-economic indexes directly influence on motor vehicles operation and reflect the interests of road users.

Vehicle speed provided by the road is taken as integral index, mostly reflects the main traffic –operational characteristics.

The index of vehicle permissible carrying capacity and axial load, road engineering equipments and road furniture is taken as additional characteristics.

The advantage is in assessment of the level of coincidence of any road parameter and characteristic with maintained demands is made according to the fact how the given parameter quantitative affects consumers requirements provided by the road.

So all the parameters and characteristics with account of their separate and mutual influence on technical-economic indexes are assessed on every characterized road section. As a result on every section there are found specific road parameters and characteristics and their combinations leading to the reduction of the consumer

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properties of the road which gives the possibility to distribute them due to the level of this affect.

Knowing the various parameters and characteristics influence on the consumer properties there are determined specific measures or their improvement up to any level of requirements of consumer properties on every road section. Devices and equipment for traffic operating condition assessment of roads is presented in fig. 1.1-1.8.

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REFERENCE

International classification of road – repair works:

Capital repair is a selective repair of separate surface sections, reconstruction of cross profile of carriage way and subgrade, improvement of drainage system with reconstruction o durability and conditions of movement along artificial structures. The cost of works can differ from $3000 and more per km for the roads with low types of road base up to $20000 and more for the roads with capital and light types of road bases in dependence of their conditions.

Reconstruction – works are consisted in the road base use of existing road grade without rout change but with rebuilding of artificial structures. The cost of the works can differ in wide rate from $45000 up $300000 per 1 km.

Renovation – works combining the elements of capital repair and reconstruction.

Reinforcement – road base thickening including pavement of new surface which can be combined with thermal profiling of existing asphalt concrete pavement. The cost of work on one road lane can be from $10000 up to $50000 per 1 km.

Road reconstruction is done or increasing of traffic speed, safety and carrying capacity. The works provide road widening, improvement of its location on the terrain with extension of the radiuses or lowering of its slopes with construction of new road base sections. The cost of the work can varied in wide rated in dependence of local conditions and designed rout change and road structures.

UNIT II

PREPARATORY WORKS DURING ROAD RECONSRUCTION

2.1.Creation of geodesic control network.

2.2.Content of additional works and measures:

а) transfer and reorganization of air, surface and underground

communications;

б) сlear of road lane and territory of side pilling and reserves; в) organization of traffic during reconstruction.

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2.1.The signs fixing the angles tops of turnings and main points of curves and also the points on straight sections not rarer than in 1km, benchmarks along the road not rarer than in 2km serve as geodesic control network.

Main signs and benchmarks should have reliable structure as poles or piles placed outside the right of way due to the special requirements.

Before the earth works there is done the detailed elaboration of geodesic control network. There is designed all the pickets and pluses on right of way, then put the additional benchmarks at the embankment higher than 3m outside the foot, at the excavations of more than 3m depth outside the slope edge, at the reconstructed artificial structures, there is placed intermediate benchmarks on the rough terrain; break simple and easement curves with removal and fixing of intermediate points are laid out.

Detailed laying out during road reconstruction can be done with groundwork of traffic flow speed.

2.2.Removal of the existing signs, barriers, marker posts or lighting masts construction and removal of pavilions on bus stops, replacement and reconstruction of communications, breaking of slope fixations, drainage trays and ditches, traffic design of scheme on the section of reconstruction is the additional works.

On the sections of bilateral widening of the road all the works are completed on two sides of the road, but on the sections of unilateral widening of the road they are done on one side.

Types and content of the mechanization means applied for removal of engineering equipment and road furniture and also slope strengthening depend on their types and work volume.

а) During the period from construction till the reconstruction the road acquires with different types of communication. They are lines of technological and general connection, power line as air lines or high voltage cables, surface and underground pipelines and other communications. More often these communications are located on right of way and can be damaged during the process of road reconstruction.

The works on replacement and rearrangement of communications should be done according to the special projects of corresponding organizations come to agreement with contractual organization.

In the case when subgrade constructed before the arrangement of underground communications crossing the road it is necessary to provide preliminary placing of shrouds or another facilities for further communication lining without the damage of subgrade integrity. For that it is necessary to confirm it with interested organizations. b) Road line is cleared on separate sections by the same mechanisms and means as at new road construction. Side ditches-reserves (especially in the II road climatic zone) are overgrown with marsh vegetation and moister-loving bushes. The road line clearance works is executed with bush breaker and bulldozer in summer

time or at the beginning of dry autumn.

Machines and gears for right of way cleanup are presented in fig. 2.1-2.8.

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After clearance of road line on the whole territory where there is needed earth works soil fertile layer is removed into the designed depth and stacking it for further reclaiming. Meanwhile it is necessary to pay attention on the quality and content of fertile soil.

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It is established that at high temperature traffic intensity on the right of way with 50m width the soil pollution can be occurred by traffic emissions which contain lead, zink, copper, nitrates and chlorides. In this case polluted soil is stored separately and used in lower layers while filling up ravines, improving sited etc.

The removal of fertile soil is done with motor graders and bulldozers. On the territory of high fillings and deep excavations works are executed by scraper or excavator bucket with telescope boom.

c) Road building organization responsible for reconstruction is to provide uninterrupted traffic and construction transport movement. According to the road technical regulations and maintenance a bypass should provide traffic with speed not less than 30km per hour.

In the regions with dense net of existing roads it is possible to carry part of the traffic on the parallel roads. It significantly unloads bypasses.

Bypasses are organized due to the following variants:

1.Arrangement of bypass parallel to the road under reconstruction.

At favorable soil and hydrological conditions it is possible to use only profiled dirt road. Road base of simple types (gravel, slag, soil improved with large-skeletal additives) is constructed only on low places. In order to support satisfactory traffic along the objects with weak road base it is necessary to repair them. Special brigades are existed for these works.

Exemplary equipment for such a brigade:

1. Motor grader with scarifier, 1 bulldozer, 1compactor, 2-4 automobile – dumpers.

Bypass is to be constructed along the whole reconstructed road. The application of such objects can be admitted at low traffic intensity (up to 1000 vehicles per day.

Amount of expenses of the building organization for the provision of traffic onto bypass:

Сс – cost of bypass construction with account of ramps from the main road; Сэ

– expenses for bypass maintenance and for periodical vehicle towing, Со – expenses for temporary alienation of land for arrangement of bypass and further reclamation; Ст – diseconomies from the traffic expenses growth at motor cars passing along the bypass:

where С1 – cost price of transportation (1t/km) due to the existing road; С2 – the same along the bypass; Q – average day volume of transportation during the whole period of its operation; Т– work duration of reconstruction; t – amount of days when traffic along the bypass completely stop; Спр – diseconomies from the times out during slash;

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