The concept of “artificial structures” is used as a generic name for various objects that are erected at the places where roads intersect rivers, streams, other transport lines, melt and rainwater flows, deep gorges, urban areas, and mountain ranges. What is all this for?
Introductory information
The creation of artificial structures allows us to solve such problems:
- Provides safe movement of people over transport routes.
- Allows to achieve stability of deformable and round slopes.
- Regulates water flows to protect paths from erosion and waterlogging.
Examples include bridges and tunnels, pipes, viaducts, overpasses, retaining walls, pedestrian bridges, regulatory structures, galleries, siphons, mudflows, high-speed currents, trays, berths of ferry crossings, filtering embankments. It should be noted that there is a very clear bias towards individual representatives. So, on some bridges and pipes falls more than ninety percent of all structures.
What is their purpose?
The design of the facilities created is very complex and expensive. In addition, the maintenance of artificial structures costs a considerable amount. Replacing them is a difficult matter. Therefore, it is not surprising that they are calculated for a long service life. At the same time, an interesting pattern is observed - artificial structures, which are built at different times according to various projects, meet certain specific technical requirements, and also differ in terms of their purpose, types of structures, implementation systems and bearing capacity. The combination of these factors greatly complicates the operation, repair and maintenance. Let's look at individual representatives of this group of structures.
What are they like?
And you should start here with bridges. In this case, the following objects should be mentioned:
- The bridge itself. It is a structure along which a certain road goes through a specific obstacle. For example, railroad tracks thus often cross water barriers. Although there may be a deep gorge, the road is for another type of transport.
- Overpass They are found at the intersection of roads and railways.
- Bridge overpass. The basis for the roads in big cities. Overpasses are a kind of bridges for which an infrequent and even distribution of supports is provided. This is done in order to less restrict the streets and provide convenient passage / passage under them.
- Viaduct. These are high bridges used to cross mountain gorges, deep ravines and valleys.
- Aqueduct. This means a bridge or overpass with a conduit made in the form of a pipe, tray, channel. It is constructed in cases where the place of fluid flow intersects with a gorge, river, road, ravine, as well as a number of other obstacles.
- Pedestrian bridge. It is created to ensure the safety of people during the transition through potentially dangerous parts of the terrain. For example, suburban platforms, large stations, a tunnel, a major freeway, and numerous train tracks.
This is not the whole list.
There are many more types and classifications of artificial structures, which include objects of special purpose. For example, bridges must be not only reliable enough to allow transport to move quietly, but also, if necessary, ensure safe and free passage of water, as well as river / sea transport. They must be classified on the basis of design standards for their carrying capacity. Depending on the width of the obstacle to be crossed, design features and elevation above the ground, they can be one-, two-, three- and multi-span. Do not forget about underground structures. Culverts can be used as a popular option . They are being constructed in such a way as to ensure the current demand for supplies, as well as taking into account development in the next 15-20 years.
About tunnels
Very often they are laid in mountainous areas. This is done in order to avoid numerous rounds, development of deep excavations and for other similar reasons. On a given track remove the rock. The resulting production is fixed with concrete, stone, metal tubing. When conducting tunnel work, there are two main ways of working:
- In rocky soils, the development of temporary support is fixed.
- A tunnel shield is used.
The created underground structures according to their purpose are divided into road, rail, metro, hydraulic, mining, communal and several others. Often they settle down not only in mountainous areas, but also under the riverbed (a combination of these factors is not excluded). As a rule, it is assumed that the longitudinal profile in one or both sides should not have a slope of more than 3 ‰. Although there are exceptions. In addition, additional requirements may be introduced for the facilities being constructed. For example, if you plan to arrange the tunnel in a curve, then the radius for it should be at least 600 meters. During the construction of facilities, the length of which will be 1000 m and more, it is necessary to provide artificial ventilation (if it is planned to use vehicles on steam / diesel traction). Concrete finishes are provided for tunnels; iron inserts and structures are often used. If you have to create an object in difficult hydrogeological conditions, then metal is used for decoration.
Other artificial structures
The list can be kept for a very long time. This is the embankment, which is used as an integral part when laying the road, and the dam. It should be noted that very often there is a consideration of the concept of “artificial structures” from the position of referring to them everything that a person did. This point of view has a right to exist. But basically they mean a limited list of objects. So, a dam with a road at the very top is considered an artificial structure. Although to hear the same definition in relation to a private house is very problematic. Although both of them were built by people and, in fact, are artificial structures.
About construction
This process is not very different from the construction of ordinary buildings. Although it is necessary to take into account certain features. For example, if a bridge is being built across the river, it should be borne in mind that it can wash away supporting structures over time. And this will increase the likelihood of collapse. Therefore, it is necessary to erect the structure in such a way that it has a certain margin of safety. But this is far from the only moment that has to be taken into account. For example, bridges and tunnels may require repairs in the future. And at the same time, closing the object is not permissible due to certain reasons. In this case, it is necessary to provide for the possibility of performing the necessary actions without interrupting the main functional purpose of the object. The construction of artificial structures must also comply with applicable norms and rules.
About operation
It’s not enough to build something. It is still necessary to adequately use the object and prevent the development of problems. Let's say there is a bridge across the river. What about operation? First of all, it is necessary to establish a clear limit on the loads. For example, if an object is designed to withstand 100 tons at the same time, then it should not be very long. In addition, as a rule, the load at a certain point is very relevant here. In other words, a restriction may be imposed on the weight of vehicles that cross an object. A very common situation is when the bridge over the river has a weight ceiling for trucks that want to cross it. For example, 20 tons. Sometimes even their movement is generally prohibited, because the object is intended only for passenger transport. The question is how much such restrictions are respected. After all, if a bridge was built for cars, and freight transport was forbidden, and the truck was loaded to the eyeballs (for example, 30 tons), this could result in an accident.
About the content
The best problem is one that has been prevented in time. Of course, you can wait until the very last moment, then to catch on and thoroughly correct the situation, carrying out expensive repairs. But the facility can last much longer if it is simply given enough time for maintenance. For example, we have a bridge over a gorge made of concrete. The content requires periodic inspection and elimination of problems until they become widespread. For example: a crack has occurred. If it is quickly and efficiently glossed over, then a year or several you can be calm. But if you miss the moment, wait for the autumn rains and winter frosts, then in the spring the object will already begin to creep. And there will be not a small crack, but an already gaping hole. Therefore, the content is very important when it comes to the long-term operation.
About repair
If it was not possible to save from negative factors, they have too much destructive force (earthquake) or the object simply crumbles from old age, then it is necessary to restore it. Repair can be both small (repair of individual cracks), and capital. The first option is cheaper, although it often needs to be done. Overhaul can significantly extend the life of the unit. Although it costs a considerable amount of money. Consider a small example. There are artificial structures on the roads - bridges. A small crack went. If it was immediately repaired (even if it is processed once a year - in the spring), then in ten years the bridge will still be suitable for use. Although, perhaps, his appearance will not be the best. If you ignore the problems, then it is likely that in ten years you can use this bridge only after major repairs and significant infusions of cash.
Conclusion
So we examined what artificial structures are, what they are, what are the features of their construction, operation, maintenance and repair. Of course, the information provided is not enough to learn how to design and build such objects yourself. But you can understand the subject of the article and support a thematic conversation.