RAILWAY AND MOTORWAY ENGINEERING STRUCTURES

Roads are one of the most important means for the transportation of people, goods and freight over land. Their construction needs considerable time and energy. The invention of the wheel has greatly contributed to solving the problem of overland transportation but its introduction went along with its own technical problems. Trunk-railways and motorways had to overcome different natural barriers such as mountain ranges, bodies of water, fast-flowing rivers, deep gorges and depressions, as well as urban structures. People had to build railway and motorway engineering structures to provide a passing by these natural and manmade barriers.

The term “railway and motorway engineering structures” (R&M ES) denotes a complex of structures used for traffic that intersect various obstacles. Some of these structures intend to protect trains and other vehicles against adverse environmental influences or natural calamities. This term incorporates the following structures: aqueducts, bridges, flyovers, overhead roads, viaducts, pipelines, culverts, tunnels, galleries, retaining and revetment walls. The function of these structures is quite different from that of civil engineering structures. Therefore, the term does not include buildings, garages, etc. even though they are also manmade structures.

The word artificial cannot relate to railway and motorway engineering structures because this word is associated with artificial building materials and other manmade structures. The origin of the Russian term “ИССО” (“R&M ES”) relates to the idea of art. The first railway engineers were scientists, artists and builders simultaneously. They possessed deep knowledge in different fields required for the construction of railway and motorway engineering structures. Skilled individuals with the highest qualification and experience, and gifted by Nature, possessed artistic abilities, and applied their creative skills and imagination for constructing engineering structures to be appreciated not only for their engineering achievement but for emotional influence as well. At present, according to tradition, railway engineers express their creative abilities to designing functional bridges and tunnels that introduce an artistic element into the surrounding environment. They use calculations for expressing their imagination and demonstrate their skills in the use of building materials.

R&M ES are the most complicated and expensive structures. Their share ranges from 15 to 50% of the total capital investment in the construction of road networks. However, the length of these structures does not exceed 5% of the overall road length. Obstacles at the building site determine the R&M ES type, whereas there are more than 20 types of them divided into two main groups: bridge structures (fig. 1.1) and tunnel structures (fig. 1.2).

People have to build a bridge when the obstruction of a road is due to a river or another body of water (fig. 1.1a). If the barrier is a narrow stream or a temporary channel, it is much cheaper to build a culvert (fig. 1.1b). Bridges carry railways (fig. 1.3a), motor vehicles, or pedestrians, and support pipelines, chutes or other conduits that transport materials, such as an oil pipeline or a water aqueduct.

Railway and motorway engineering structures such as viaducts, flyovers and overhead roads are often confused when describing them (fig. 1.1c, d and e; 1.3b, c, d and f).

Figure 1.1 R&M ES of Bridge Type Figure 1.2 R&M ES of Tunnel Type

a – Railway Bridge	b – Viaduct
c – Overhead Road (эстакада)	d – Overhead Roads and Flyovers
e – Gallery (left), Tunnel (right)	f – Flyover, Overpass (путепровод)

Figure 1.3 Railway and Motorway Engineering Structures

People have always been concerned with finding ways to cross gorges, canyons and ravines, trying to provide faster crossing for traffic and pedestrians. They build viaducts (fig. 1.1c; 1.4; 1.3b) to reduce long distances. Level crossings and heavy traffic call for overpasses. The solution to this problem is a flyover, which provides an overhead crossing and regulates vehicle density (fig.1.3c, d). Overhead roads are nessessary in cities where houses, parks and industrial areas affect traffic flows (fig. 1.1d). As a rule, overhead roads are rather long structures (fig.1.3c).

Tunnel works are divided into tunnels driven through mountain ranges (fig. 1.2a), and galleries located on mountain slopes (fig. 1.2b; 1.3e). They protect roads from rockslides, snow slips, avalanches, drifting snow, sand drift, and mudflows or torrents. Retaining walls, revetment walls and balconies can provide a high degree of road protection from disasters. They are less complicated tunnel structures (fig. 1.2c, d, and e).