Road and path construction
The road construction includes the design, manufacture and maintenance of roads and paths for pedestrian and vehicular traffic. Road and path construction as such includes the production of the unbound superstructure layers, the paving work and asphalt work, as well as the construction of drainage systems and embankment fortifications as well as road equipment . In a broader sense, road and path construction is part of transport engineering and is therefore one of the sub-areas of civil engineering .
The construction of roads and paths is necessary because naturally grown soil is unsuitable as a traffic area and cannot meet the requirements of modern transport and traffic . One of the goals of modern road construction is to create permanent and safe traffic areas that are as environmentally friendly and economical as possible.
Road construction works closely with other civil engineering departments . This includes in particular earthworks , with the help of which the site is prepared for road construction. With the help of bridge construction and tunnel construction , engineering structures for road construction are created.
In the following, the historical development of road and path construction from the beginnings to the present is presented. In doing so, aspects of construction technology are primarily considered.
Road and path construction is firmly connected to human history and goes back to its beginnings. The first paths, however, were not “built” according to plan, but were given by nature. People learned to use the natural conditions for hunting and transportation. Permanent fortification was not necessary due to the nomadic existence . Only with the settling down and the emergence of advanced cultures (invention of the wheel) were first paths and later roads laid. This enabled people and goods to be transported more quickly and conveniently. Wide streets were initially only intended for religious purposes or to illustrate the claim to rule. In addition to trade ( trade routes ), military purposes ( military roads ) were also decisive for the construction of extensive road and path networks. In early antiquity, as far as we know, the Babylonians, Egyptians and Persians were the first peoples who took advantage of an extensive transport network and developed special techniques in this area. The construction technology of these early streets was very different and dependent on the level of development of the respective culture. In addition to simple earth roads, boardwalks or gravel roads were also laid out at this time . Special boulevards, such as the processional street in Babylon, were paved early on.
With the expansion of the Roman Empire and the constant further development of road construction technology, an extremely durable and extensive network of roads and paths was created in Europe. Many of these Roman roads still exist today, the route of many trunk roads (especially in the Alps) coincides with the route of the Roman roads of that time. In addition to paving, the Roman builders also used the ancient form of concrete ( Opus caementitium ) to pave the streets. Below the top layer there were various layers of fine and coarse rock to improve load-bearing capacity and durability. They were also built with a bank slope so that the rainwater was drained quickly.
After road construction had made extraordinary progress in the time of the Romans and a "road building art" had developed, knowledge of road construction fell into oblivion at the beginning of the Middle Ages. In many places, little permanent dirt roads were laid, only a few city streets were paved with paving. The existing Roman roads were still used, but increasingly fell into disrepair due to war and lack of maintenance. It was only when road tolls were levied that part of the income was invested in road construction and road maintenance.
It was not until the beginning of the 18th century that there were new developments in the field of road construction technology. Initially, it was primarily French engineers from the École nationale des ponts et chaussées , such as Daniel-Charles Trudaine , Pierre Marie Jérôme Trésaguet or Hubert Gautier , who carried out the relevant investigations. They found that durability is directly related to the load-bearing capacity of the substructure and the tightness of the top layer. In addition, the road drainage was further developed.
In addition to French engineers, other engineers in other parts of Europe were also looking for ways to make road construction more durable and economical. The Scot John Loudon McAdam developed a gravel construction ( macadam ), the grain structure of which became finer from bottom to top. His compatriot Thomas Telford dealt with the banking and alignment of roads.
Inspired by the French model, art roads or highways were also built in German-speaking countries from the beginning of the 18th century , for example in the Electorate of Cologne a paved road between Cologne and Bonn as early as 1727 . Prince Leopold III. Friedrich Franz von Anhalt-Dessau created a system of “Lustchausseen” around Dessau and Wörlitz as part of his landscape designs . In Prussia , the planned modern road expansion began under King Friedrich Wilhelm II in the last third of the 18th century. A test route that was set up at the time has been preserved to this day in the New Garden in Potsdam . In 1791 Hanns Moritz von Brühl was appointed the Prussian road construction manager and was thus head of the first Prussian road construction authority. This marked the beginning of the planned and extensive expansion of modern roads in Prussia. The Berlin-Potsdamer Chaussee , which was started in 1791 , is still visible today along Bundesstrasse 1 from Potsdamer Platz to Glienicker Bridge and on to the center of Potsdam. Sections of the original avenue and several milestones have also been preserved .
With the increase in traffic (especially with the emergence of motor vehicles) and the wheel load, the demands on road pavements also increased. The development of dust was particularly problematic. For this reason, at the beginning of the 20th century , Ernest Guglielminetti tried to bind the surface of a road with the help of tar . From then on, they started using tar, bitumen or cement to bind the surface layers that were unbound at this point in time , and using them to develop new construction methods. The emergence of high-performance earthworks and road construction machines, such as those of the German industrialist Julius Kemna , contributed to the fact that the formerly very time-consuming and personnel-intensive road construction could be carried out more economically and faster and that large construction projects such as the motorway could be tackled could.
Roads and paths are still the most important means of transport for transporting people and goods. For this reason, the existing road network is constantly being repaired and expanded in places. The construction technology and the construction methods are continuously developed and optimized in order to meet the increasing requirements in terms of quality, economy and road safety. In particular, the protection of people and the environment have become increasingly important and require new solutions for the construction of roads and paths.
A comprehensive road design is fundamental for road and path construction. This goes through different stages and is concretized with each stage. The traffic congestion on a route or the removal of a hotspot of an accident can be decisive for road planning. However, there is also the possibility that state development programs provide for the construction of a road to open up and develop structurally weak regions.
The route specified in the road design must be assessed with regard to its traffic safety and environmental compatibility. Furthermore, it has to be checked for economy and traffic effectiveness. All new or expansion projects are summarized in action plans or assessed according to their urgency. At the German federal level, for example, this is the requirement plan for federal trunk roads ; in Switzerland, ASTRA defines the future national road network .
In addition to the elaboration of the technical design, the road design is also influenced by internal administrative procedures that grant public funds and building permits, and political processes, e.g. B. by referendums , accompanied. During the design phase, numerous authorities and interest groups (in Germany the so-called public bodies) are involved in the planning. You can significantly influence the planning project.
At the beginning of the draft there is the preliminary planning (also called line design or preliminary investigation). This is followed by the spatial planning procedure, which checks the compatibility of the route with the objectives of spatial and regional planning. If the line definition has been successfully completed , a preliminary draft can be drawn up. This already contains the concrete components of the road design and is used for internal approval or provision of public funds. In the subsequent step of planning approval, the measure is presented in detail and coordinated with all conflict parties. With the end of the plan approval (plan approval decision) the building permit is available. A detailed construction draft is prepared for the tender and execution .
This planning process is usually used when building new higher-level roads. Smaller construction and maintenance measures, on the other hand, do not have to be treated in this way, as their effects on people and nature are not significantly large.
The technical processing of the road design is based on regulations and guidelines that contain all the constructive issues of road planning. These draft guidelines are generally binding, but can also be changed for reasons of economy and expediency. The interests of traffic safety must not be violated.
The construction load of roads as the basis of road traffic can, depending on the state, be divided between the state, member states (e.g. federal states, cantons) and municipalities. In Germany, the federal states, and in some federal states also the districts , are road construction authorities. Often, as in German-speaking countries, for roads of national importance ( trunk roads ), the federal government bears the construction load, subordinate connections are assigned to the member states or the municipalities.
Road and path construction also affects the lives of residents, on the one hand through a better connection to the road network, but on the other hand also with impairments from noise emissions and exhaust gases.
In Germany, the Bundestag specifies the expansion or new construction requirements for federal highways , federal highways , railways and waterways . The road construction offices of the federal states carry out the planning, construction and maintenance, which must be approved by the Federal Ministry of Transport . The process is regulated in the Federal Trunk Road Act and Federal Waterways Act and is divided into five phases:
- Demand planning: Every road planning begins with the demand plans legally prescribed by politicians. One of the most important means is the Federal Transport Infrastructure Plan (BVWP) . The routes to be built are thus determined and given an urgency level. In a preliminary stage, proposals are submitted by the municipal levels via the federal states. The Bundestag finally decides on the projects to be included in the plan. The Federal Transport Infrastructure Plan 2030 is currently up to date .
- Pre-planning: The pre-planning determines the rough routing as well as the roads to be connected without crossing, if necessary. In particular, costs, traffic efficiency and protection needs for people and the environment must be taken into account. In this planning phase, organizations and private individuals can only comment on the plans in an advisory capacity after they have been displayed in the participating municipalities. Sometimes this also happens in citizens' assemblies. The preliminary planning concludes with the definition of the line.
- Draft planning: This is where the detailed, centimeter-accurate planning of the traffic area in terms of area and height takes place.
- Plan approval procedure: The plan approval procedure concludes with the plan approval decision, which makes the construction of the traffic route complainable. Therefore, in the course of this, all affected public and private interests must be weighed against each other and conflicting interests balanced. The public display of the plans as well as a legally binding hearing and handling of objections are part of this planning phase. If, after the planning approval decision, lawsuits against the latter are rejected by the courts or amicable settlements are reached, this will finally become legally secure and enforceable.
- Execution planning, awarding and construction: This is where the tendering, awarding and construction work takes place until approval.
The alignment describes the development of the lines of a road. The road axis is usually used as the reference line for this.
In order to present the information of a road plan in a generally understandable and comprehensive manner, plans are created with different scales and levels of detail. Furthermore, the plans adopt different display views in order to depict the street as a spatial curve. The following planning documents are a core part of a road design:
Road construction technology
In road and path construction, numerous construction techniques and construction methods have developed over the course of time, with the help of which it is possible to build permanent and safe roads and paths. Road construction technology uses various building materials and construction methods for this purpose. Another element of road construction technology is road drainage and landscape maintenance.
In road craft streets and roads of different materials as are asphalt , concrete , plaster , large-format or from unbound material (e.g. gravel ) were prepared (top layer and backing layer ). In the case of larger construction projects, production takes place with a paver for asphalt roads or with a concrete paver or slipform paver for concrete roads. Small construction work and repairs are often carried out manually. Asphalt is flexible up to a certain temperature range. Therefore form on heavily loaded areas over time ruts . If the outside temperature is too high, asphalt can become deformed and damaged.
Important points in road construction are:
- Choice of machines used ,
- Choice of built-in material ,
- Observance of the environmental conditions ( temperature , rain, etc.),
- sufficient compaction at the correct asphalt temperature.
The drainage of road structures is of fundamental importance, as this is the only way to prevent surface water from penetrating the structure and thus leading to destruction. Furthermore, traffic safety is guaranteed, since aquaplaning and ice surface formation are prevented. For this reason, the road surface has a sufficient slope in the longitudinal and / or transverse direction, which reliably drains the water to the side. There it can either seep away or be diverted to the receiving water with the help of ditches or collecting pipes .
If the road structure is almost flat, the drainage is made in the longitudinal direction, for example with a so-called "pendulum channel" made of mastic asphalt or 1–3 rows of paving stones, for example "Homburg Edge" made of natural or concrete cubes. The total area to be drained should not exceed 500 m².
Road structures that have a transverse slope, so-called "roof or desk profiles" drain either from the middle of the street (roof) or from the right or left edge of the lane (desk).
Road construction work in Germany is described, for example, in VOB Part C: General Technical Regulations (ATV) paving and paving slabs DIN 18318 and track layers with bituminous binders VOB Part C: DIN 18317.
In addition to the construction of the actual road structure, adding and maintaining the road equipment is part of the road construction. Only then is it possible to use the road safely. Components of the road equipment are, for example, lane markings , passive protective devices (concrete sliding wall or steel guardrail, also called guardrail), signposting, signposting of the road traffic regulations, lighting and light signal systems, also called traffic lights .
In order to guarantee the durability of roads and to save financial resources, the roads themselves and the associated building materials must be checked for their properties during manufacture. For this purpose, test arrangements can be carried out on site or samples can be taken and then examined in the laboratory.
The construction of bridges or crossings can make it necessary to set up temporary construction roads.
Road maintenance as part of road construction includes all measures to maintain the utility value of a paved traffic route and to ensure safety for road users. For this purpose, regular condition checks and, if necessary, measures for maintenance, repair or renewal are required .
Road construction finance
Federal trunk roads
The roads in Germany are financed through taxes and - in the case of the federal trunk road network, which accounts for the bulk of the road service with 72% in freight transport and 56% in passenger transport - additionally through the truck toll. On April 15, 2011, the Bundestag passed the law on the revision of the toll regulations for federal highways, according to which the funds from the federal government are to be used for the construction of federal highways. In 2011 this is around € 3.2 billion. They are supplemented by funds from the general budget. However, the annual amount is not fixed and results from year to year from the respective budgetary decisions. With these, the still existing statutory earmarking of 50% of the mineral oil tax revenue (in 2008: € 33.6 billion) for road construction, as anchored in Article 1 of the Road Construction Financing Act of 1965, is expressly renewed again and again exposed.
In total, the funds for federal trunk road construction amount to € 4.9 billion for 2011 and the three following years. At the time, the government commission on transport infrastructure financing through the so-called “ Pällmann commission ” estimated an investment line of at least € 6 billion a year as a need-based investment level . In view of the increase in the cost of road construction work since then, this amount is still around 20 percent higher today.
State, district and municipal roads
The state, district and municipal roads are financed by the respective federal regional authority, whereby the municipalities provide additional federal funds for investment in their municipal transport infrastructure (road and rail-bound public transport) in accordance with the Municipal Transport Financing Act (GVFG) to get. This amounts to around € 1.34 billion annually. Their commitment for transport purposes will expire after 2013. As of 2014, the amount of funds is to be checked and, if necessary, reduced. For the period up to 2019, the federal and state governments have agreed to keep the funds at the same level as part of the 2013 flood aid.
The volume for road construction measures in the municipalities in 2009 was around € 4.4 billion. This means that the municipal road network is also considered to be underfunded. An annual investment requirement of € 10.8 billion is assumed here.
In particular, so-called service roads are often financed proportionally through contributions to development and road construction. Here, the property owners of the adjacent properties pay one-off contributions for the renewal, improvement and expansion of the streets, depending on the size of the property and the potential for building. Details can be found in the Building Code (BauGB) and in the local tax laws of the individual countries. Not all federal states make use of this.
- List of topics for road and path construction
- Transport engineering
- List of technical regulations for the road system in Germany
- Flatness measurement of roads with the planograph
- Siegfried Velske, Horst Mentlein, Peter Eymann: Road construction technology . Werner Verlag, Düsseldorf 2009, ISBN 978-3-8041-3879-7 .
- The road construction. In: August van Kaven: Lectures on engineering sciences at the polytechnic school in Aachen. Hanover 1870, pp. 81-322. ( Full text in google book search)
- Günter Wolf: Road planning . Werner Verlag, Munich 2005, ISBN 3-8041-5003-9 .
- M. Lorenz, J. Lorenz: Handbook road construction . Fraunhofer IRB Verlag, Stuttgart 2006, ISBN 3-8167-7083-5 .
- E. Straube, K. Krass: Road construction and road maintenance . Erich Schmid Verlag, Berlin 2005, ISBN 3-503-09067-3 .
- Henning Natzschka: Road construction: design and construction technology . Vieweg + Teubner Verlag, Wiesbaden 2003, ISBN 3-519-15256-8 .
- Time knowledge topic road construction
- The road construction test route Braunschweig
- Pflasterer's Hard Craft - How the City came to the street. ( Memento from February 17, 2013 in the web archive archive.today )
- E. Straube, K. Krass: Road construction and road maintenance . Erich Schmid Verlag, Berlin 2005, ISBN 3-503-09067-3 .
- Federal Statistical Office, Fachserie 4, Reihe 5.1, 2011, p. 8.
- Herbert Liman: Prussian road construction, milestones in Berlin. (= Berliner Hefte. 5). Berlin 1993, p. 6 ff.
- German Bundestag, road construction report 2004 (printed matter 15/4609), p. 10.
- Financial planning 2014 of the federal government (decided on July 7, 2010), Federal Ministry of Finance 2010.
- Transport Infrastructure Commission, final report, September 5, 2000, p. 19.
- Federal Statistical Office, Price Indices for the Construction Industry , February 2011, Wiesbaden 2011, p. 23.
- Act on the unbundling of joint tasks and financial aid, Art. 3.
- Federal Statistical Office 2010.
- T. Bracher et al. (German Institute for Urbanism): Investment backlog and investment needs of the municipalities. edition difu, 4, 2008.