Road characteristics: road categories, road surfacing. Other road enginering structures.

Lecturer I. Piščikienė

Vilnius 2013 Introduction

Content World bridges…………………………………………………………………………………………………..4 World longest tunnels………………………………………………………………………………………6 Types of roads………………………………………………………………………………………………….7 Roads surfacing……………………………………………………………………………………………….10 Conclusions……………………………………………………………………………………………………..13 List of sources………………………………………………………………………………………………….14

World bridges
The world’s longest bridge is the Danyang-Kunsgan Grand Bridge(1) in China, part of the Beijing-Shanghai High-Speed Railway. The bridge, which opened in June 2011, spans 165 kilometres. This bridge constructed in just 4 years, employing 10.000 workers, at a cost of about 8.5 million dollars. It crosses low rice paddies, part of the Yangtze River Delta, with just a few miles of the bridge actually crossing the open water of Yangcheng Lake in Suzhou. The bridge averages about 31 meters off the ground.

1.Danyang-Kunsgan Grand Bridge

The sidu river bridge(2) is the tallest bridge in the world, standing around 1.500 ft tall. The are exactly 1.550 feet from the bottom of the bridge to the valley floor. It is located at the border of Yichang and En’shi in the Hubei province. It is 1365 meters across. This bridge connects Shanghai on the pacific coast with Chongqing and Chengdu in the west. There was no controversy over the building of this bridge. It was needed in order to pass over the Sidu River.

2.Sidu river bridge

The Great Belt Fixed Link(3) rail and road project, which provides the first physical link between Denmark and Sweden, is amongst the largest ever undertaken in Scandinavia. By mid-2003, some 34 million journeys had been recorded, increasing north-south journeys by 77%, and commuter business 15-fold.

By creating a bridge and tunnel linking Zealand and the national capital, Copenhagen, with the major cities of the rest of the country on the Jutland peninsula, the continent has embarked upon a grand plan for physical links and through-rail services between Norway, Sweden, Denmark and Germany. The importance of this project is illustrated in the fact that its completion leaves Ireland as the only European nation not physically connected to the rest of the continent.

3.Great Belt Fixed Link

The Golden Gate Bridge(4) is a suspension bridge spanning the Golden Gate strait, the mile-wide, three-mile-long channel between San Francisco Bay and the Pacific Ocean. The structure links the U.S. city of San Francisco, on the northern tip of the San Francisco Peninsula, to Marin County. It is one of the most internationally recognized symbols of San Francisco, California, and the United States. It has been declared one of the Wonders of the Modern World by the American Society of Civil Engineers.

4.Golden Gate Bridge

The Millau Viaduct is a cable-stayed bridge that spans the valley of the River Tarn near Millau in southern France. Designed by the French structural engineer Michel Virlogeux and British architect Norman Foster, it is the tallest bridge in the world with one mast's summit at 343.0 metres (1,125 ft) above the base of the structure.It is the 12th highest bridge deck in the world, being 270 metres (890 ft) between the road deck and the ground below.Millau Viaduct is part of the A75-A71 autoroute axis from Paris to Montpellier. Construction cost was approximately €400 million. It was formally inaugurated on 14 December 2004, and opened to traffic on 16 December.The bridge has been consistently ranked as one of the great engineering achievements of all time.The bridge received the 2006 International Association for Bridge and Structural Engineering Outstanding Structure Award.

World longest tunnels

Laerdal tunnel(5) is a 24.51 kilometers long road tunnel connecting Laerdal and Aurland in Sogn og Fjordane, Norway and located approximately 175–200 kilometres (109–120 mi) north-east of Bergen. A total of 2,500,000 cubic metres of rock was removed from the tunnel during its construction from 1995 to 2000. The tunnel begins just east of Aurlandsvangen in Aurland and goes through a mountain range and ends 5.5 kilometres south of Lærdalsoyri in Lærdal. The design of the tunnel takes into consideration the mental strain on drivers, so the tunnel is divided into four sections, separated by three large mountain caves at 6-kilometre intervals. While the main tunnel has white lights, the caves have blue lighting with yellow lights at the fringes to give an impression of sunrise. The caves are meant to break the routine, providing a refreshing view and allowing drivers to take a short rest. The caverns are also used as turn around points and for break areas to help lift claustrophobia during a 20-minute drive through the tunnel. To keep drivers from being inattentive or falling asleep, each lane is supplied with a loud rumble strip toward the center.

5.Laerdal tunnel in Norway

The 2 x 18,020 m-long Zhongnanshan tunnel is on the Xi'an-Ankang highway, which is part of a national highway linking Baotou in Inner Mongolia in North China to Beihai in Guangxi Zhuang autonomous region in South China. It starts in Qingcha, Xi'an City and ends in Yingpan, Shangluo City. It is the longest road tunnel in Asia and the second in the world after the 24.5 km Aurland-Laerdal single-tube tunnel between Oslo and Bergen in Norway, opened in November 2000. The tunnel will play an important role in reducing travelling times in the Shaanxi province, cutting the drive from Xi'an to Zha Shui County Town from three hours to 40 minutes. As a main connection between the Yellow River economic belt and the Yangtze River delta economic circle, it will greatly reduce transportation costs and further promote the economic development alongside the highway.
Types of roads

1. German autobahns
The German autobahns form the nationally coordinated motorway system in Germany. Each of them is officially referred to as a Bundesautobahn (plural Bundesautobahnen, abbreviated BAB), which translates as "federal expressway". German autobahns have no federally mandated blanket speed limit, although limits are posted and enforced in areas that are urbanized, substandard, accident-prone, or under construction or bad weather conditions. On speed-unrestricted stretches, an advisory speed limit of 130 kilometres per hour applies. In 2008, the State of Bremen, geographically smallest of the sixteen States, imposed a 120 km/h general speed limit, although this applied to only 11 kilometers of Autobahn 27 connecting the cities of Bremen and Bremerhaven.
Germany's autobahn network has a total length of about 12,845 kilometres (7,982 mi) in 2012, which ranks as the fourth longest highway system in the world behind the National Trunk Highway System (NTHS) of China (97,355 km), the Interstate Highway System of the United States (75,932 km) and the highways in Spain (16,204 km).

2. Street
A street is a paved public thoroughfare in a built environment. It is a public parcel of land adjoining buildings in an urban context, on which people may freely assemble, interact, and move about. A street can be as simple as a level patch of dirt, but is more often paved with a hard, durable surface such as concrete, cobblestone or brick. Portions may also be smoothed with asphalt, embedded with rails, or otherwise prepared to accommodate non-pedestrian traffic.
Originally the word "street" simply meant a paved road. The word "street" is still sometimes used colloquially as a synonym for "road", for example in connection with the ancient Watling Street, but city residents and urban planners draw a crucial modern distinction: a road's main function is transportation, while streets facilitate public interaction. Examples of streets include pedestrian streets, alleys, and city-centrestreets too crowded for road vehicles to pass. Conversely, highways and motorways are types of roads, but few would refer to them as streets.

3. Thoroughfare
A thoroughfare is a transportation route connecting one location to another. Highways, roads, and trails are examples of thoroughfares used by a variety of traffic. On land a thoroughfare may refer to anything from a rough trail to a multi-lane highway with grade separated junctions; on water a thoroughfare may refer to a strait, channel or waterway. The term may also refer to the legal right to use a particular way as distinct from the way itself.

4. Controlled-access highway
A controlled-access highway is a highway designed for high-speed vehicular traffic, with all traffic flow and ingress/egress regulated. Common English terms are freeway and motorway. Terms in other languages include Autobahn, autostrada, autopista, and autoroute. It can be referred to less precisely as highway or with more precise terms such as expressway, Interstate, or parkway. They may also be called limited-access highways, although this term can also refer to a class of highway with somewhat less isolation from other traffic.
A controlled-access highway provides an unhindered flow of traffic, with no traffic signals, intersections or property access. They are free of any at-grade crossings with other roads, railways, or pedestrian paths, which are instead carried by overpasses and underpasses across the highway. Entrance and exit to the highway are provided at interchanges by slip roads (ramps), which allow for speed changes between the highway and arterial roads and collector roads. On the controlled-access highway, opposing directions of travel are generally separated by a central reservation containing a traffic barrier or just a strip of grass. 5. Lane
A lane is a part of the carriageway within a road marked out for use by a single line of vehicles in such a way as to control and guide drivers for the purpose of reducing traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each direction, separated by lane markings. Major highways often have two roadways separated by a median, each with multiple lanes. A single-track road carries traffic in both directions within a single lane with passing places to allow vehicles to pass. In North America and Australia, the term also may refer to rear access roads which act as a secondary vehicular network in cities and towns. A minor rural road may be referred to as a country lane; some urban streets which began as country lanes are still called lanes, such as Drury Lane in London.

Roads surfacing

1. Asphalt
Asphalt(6) has been widely used since the 1920s. The viscous nature of the bitumen binder allows asphalt concrete to sustain significant plastic deformation, although fatigue from repeated loading over time is the most common failure mechanism. Most asphalt surfaces are laid on a gravel base, which is generally at least as thick as the asphalt layer, although some 'full depth' asphalt surfaces are laid directly on the native subgrade. In areas with very soft or expansive subgrades such as clay or peat, thick gravel bases or stabilization of the subgrade with Portland cement or lime may be required. Polypropylene and polyester geosynthetics have also been used for this purpose and in some northern countries, a layer of polystyrene boards have been used to delay and minimize frost penetration into the subgrade.

6.Asphalt road

2.Concrete
Concrete surfaces (specifically, Portland cement concrete) are created using a concrete mix of Portland cement, coarse aggregate, sand and water. In virtually all modern mixes there will also be various admixtures added to increase workability, reduce the required amount of water, mitigate harmful chemical reactions and for other beneficial purposes. In many cases there will also be Portland cement substitutes added, such as fly ash. This can reduce the cost of the concrete and improve its physical properties. The material is applied in a freshly mixed slurry, and worked mechanically to compact the interior and force some of the cement slurry to the surface to produce a smoother, denser surface free from honeycombing. The water allows the mix to combine molecularly in a chemical reaction called hydration.

3.Gravel
A gravel road(7) can be used with a traffic volume where the average annual daily traffic is 1,200 vehicles per day or less. There is some structural strength as the road surface combines a sub base and base and is topped with a double graded seal aggregate with emulsion. Besides the 4,929 kilometres of granular pavements maintained in Saskatchewan, around 40% of New Zealand roads are unbound granular pavement structures. The decision whether to pave a gravel road or not often hinges on traffic volume. It has been found that maintenance costs for gravel roads often exceed the maintenance costs for paved or surface treated roads when traffic volumes exceed 200 vehicles per day.Some communities are finding it makes sense to convert their low volume paved roads to aggregate surfaces.

7.Gravel road

4.Pavers
Pavers generally in the form of pre-cast concrete blocks, are often used for aesthetic purposes, or sometimes at port facilities that see long-duration pavement loading. Pavers are rarely used in areas that see high-speed vehicle traffic.
Brick, cobblestone, sett, and wood plank pavements were once common in urban areas throughout the world, but fell out of fashion in most countries, due to the high cost of labor required to lay and maintain them, and are typically only kept for historical or aesthetic reasons.[citation needed] In some countries, however, they are still common in local streets. Likewise, macadam and tarmac pavements can still sometimes be found buried underneath asphalt concrete or Portland cement concrete pavements, but are rarely constructed today.

5.Composite surfaces
Composite surfaces combine Portland cement concrete and asphalt. They are usually used to rehabilitate existing roadways rather than in new construction. Asphalt overlays are sometimes laid over distressed concrete to restore a smooth wearing surface. A disadvantage of this method is that movement in the joints between the underlying concrete slabs, whether from thermal expansion and contraction, or from deflection of the concrete slabs from truck axle loads, usually cause cracks, called reflective cracks in the asphalt. To decrease reflective cracking, concrete pavement is sometimes "cracked and seated." A heavy weight is dropped on the concrete to induce cracking, then a heavy roller is used to seat the resultant pieces into the subbase. The theory is frequent small cracks will spread thermal stress over a wider area than infrequent large joints, reducing the stress on the overlying asphalt pavement.

Conclusions

List of sources 1. http://en.wikipedia.org/wiki/List_of_longest_bridges_in_the_world 2. http://en.wikipedia.org/wiki/List_of_longest_tunnels_in_the_world 3. http://en.wikipedia.org/wiki/Types_of_road 4. http://en.wikipedia.org/wiki/Road_surface 5. http://www.touropia.com/most-famous-bridges-in-the-world/ 6. http://www.usatoday.com/story/travel/destinations/2013/10/15/worlds-coolest-tunnels/2914539/