CONSTRUCTION FEATURES IN SPECIAL CLIMATIC CONDITIONS

ОСОБЕННОСТИ СТРОИТЕЛЬСТВА В ОСОБЫХ КЛИМАТИЧЕСКИХ УСЛОВИЯХ

Леонова Алина Даниловна

студент, Национальный Исследовательский Московский Государственный Строительный Университет,

РФ, г. Москва

Малолетнев Никита Максимович

студент, Национальный Исследовательский Московский Государственный Строительный Университет,

РФ, г. Москва

Литвинова Татьяна Сергеевна

студент, Национальный Исследовательский Московский Государственный Строительный Университет,

РФ, г. Москва

ABSTRACT

This article deals with the technologies of construction and maintenance of buildings in special climatic conditions; it determines the main difficulties of construction in various climatic regions and ways to overcome them.

АННОТАЦИЯ

В данной статье рассматриваются технологии возведения и обслуживания зданий в особых природно-климатических условиях, определяются основные трудности строительства в различных климатических регионах и способы их преодоления.

Keywords: the construction of buildings and structures, northern regions, regions with a particularly dry and hot climate, regions with seismic activity, construction in wetlands.

Ключевые слова: строительство зданий и сооружений, северные регионы, регионы с особо сухим и жарким климатом, регионы с сейсмической активностью, строительство на заболоченных территориях.

The construction of buildings and structures, depending on the area and its natural and climatic conditions, has its own characteristics. Territorial conditions are characterized by the economic and geographical location of the construction area, the availability of natural resources and wealth, different population density and natural conditions of the regions, a low degree of economic development of the territory and the degree of economic development. The main climatic factors complicating the construction are complex technical and geological conditions, as well as seismic activity in the eastern and southern regions.

Areas with special climatic and territorial conditions include: Krasnodar and Astrakhan Regions due to the hot climate; Verkhoyansk, Oymyakon, Yakutsk, Dudinka are cities where the temperature drops below 60°C in winter; the North Caucasus and the Black Sea coast, the Kuriles and Sakhalin, Kamchatka, Baikal are dangerous regions for their seismic activity; the West Siberian plain is characterized by its wetlands.

The construction and climatic zone in the north of the country is characterized by a long winter period of 200-305 days with low negative temperatures (the average temperature in January is -18 ° C in the North, sometimes reaching up to -45 ° C); permafrost condition of soils and strong winds; small development of the territory; weak development of the construction industry.

A lot of problems arise during the construction of buildings and structures in the northern regions of the country, especially when it comes to the operation of machinery.  In winter conditions, the operation of cars is difficult due to low temperatures and severe road conditions caused by snow or ice cover.  At this time, it is difficult to start power plants, the lubricating properties of oils decrease, the viscosity of the working fluid increases, the strength properties of metal structures decrease and the loads on them increase; the fragility of rubber products increases, fuel consumption and working fluid increases. Thus, all equipment must be carefully prepared for successful operation in extreme conditions.

When erecting masonry in special climatic conditions, there are many difficulties. As a result of the action of low temperatures, the hydration of cement in the solution stops, and the solution turns into a solid mixture of ice, cement and sand. Turning into ice, the water increases in volume and as a result the solution is loosened and its strength decreases. Antifreeze additives are actively used in construction to compensate for strength. These chemical additives help to lower the freezing point of the water in the solution while speeding up the solidification process of the solution. Otherwise, when laying in winter, the wall can give uneven shrinkage, the strength of the mixture decreases, and this can lead to cracks in the wall.

However, in comparison with other types of construction processes, the installation of building structures does not undergo any significant changes. The negative impact of extreme winter conditions primarily entails a decrease in the productivity of installers and additional labor costs for auxiliary operations. In winter conditions, along with the low outdoor temperature, significant complications in the work are caused by the strength and duration of the wind, which leads to the termination of installation work. The work stops with a wind strength of 6 points and with heavy snowfall, ice and other weather conditions, which complicate the construction.

Difficulties also arise when cultivating the soil and other earthworks. Frozen soil is a complex structure consisting of ice, water and mineral particles. Due to the loss of heat and the transition of water into ice, the soil freezes, as a result of which the soil changes its physical and mechanical properties. In practice, two methods of construction are used on permafrost soils with the preservation of permafrost and with its thawing.  The first method is to preserve the soil in a frozen state both during construction and for the entire period of operation. In the second method, artificial thawing is used, which should be slow and uniform. To preserve the permafrost condition of soils, the following techniques are used:

1. Construction of buildings on backfill and provision of thermal insulation of the ground surface. This technique is designed to cool the soil. If such cooling turns out to be insufficient, then the soil will gradually warm up and thawing of the soils in the base will begin. This can lead to cracks in the foundation and walls.

2. The device of ventilated underground is used in the construction and design of residential, public and industrial buildings. In this case, the stagnation of water underground decreases.

3. The location of unheated rooms on the ground floor, they can serve as a ventilated underground. For intensive cooling, the walls of the first floor are made of heat–conducting materials, and the windows are made with single glazing.

4. The installation of pile foundations or deep laying foundations, cut into the permafrost soil below the depth of its possible thawing under the building. At the same time, laying thermal insulation under the floor of a heated building significantly reduces the depth of thawing.

  Areas with a particularly dry and hot climate have a characteristic continental dry, hot climate, aggressive radiation regime and a long duration of the summer period. In summer, air temperature and lack of moisture, strong wind and dry soil, the effects of daily temperature changes are the causes of frequent dust storms. All these areas are also characterized by high seismic activity, as well as a high prevalence of sedimentary and heaving soils containing water-soluble substances.

Earthworks in hot climatic conditions have their own characteristics that must be taken into account when designing works. Elevated temperature, low humidity and sufficiently high wind gusts lead to dehydration and solidification of the soil, during the development of which the dustiness of the air increases, productivity is reduced and the performance of tillage and transport machines is deteriorating. Therefore, when drawing up ground transport traffic patterns, when organizing their working movement against the wind direction or at an angle to it, it is necessary to take into account the wind direction. The most rational way to develop the soil in these conditions is to moisten it to optimal values, which reduces the dustiness of the air and facilitates the development of the soil.

Due to extremely high temperatures, there are some features of masonry in hot regions of our country. The distinctive features of masonry work in regions with hot and dry climates are additional measures to prevent dehydration of solutions, for which the brick must be immersed in water before laying in the structure until it is optimally or abundantly moistened with water. In order to prevent water evaporation in the parts of structures being erected, they must be covered with moisture-intensive materials, periodically moistening with water, or portable sunscreens should be installed at the construction site.

At high temperature and humidity in a dry hot climate, where the outdoor temperature is 35 - 42 ° C, as well as at high solar radiation, concreting technology slows down and even stops the waterproofing cement processes.

As a result of intensive evaporation of free water from concrete, porosity increases, frost resistance and water resistance decrease. In order to make concrete laid in a dry, hot climatic region, it is necessary to use a fast-hardening material that does not drain water well and reduces shrinkage. It is also necessary to protect the fillers from solar radiation and moisten them before starting the preparation of the mixture.

It is advisable to pour the concrete mixture at the most favorable hours of the day (in the evening, morning or at night). Conditions for the normal hardening of newly laid concrete must be created artificially. This method consists of making a tarpaulin covering on exposed concrete surfaces and regularly moistening it every 3-4 hours.

In hot, as well as in extreme winter, climatic conditions there are some peculiarities in the installation of building structures. High temperatures and dust storms in regions with hot climates require builders to take special measures to seal joints in buildings and structures made of precast reinforced concrete. Various materials with high elasticity, moisture resistance and heat resistance are used for sealing and thermal insulation of joints.

In regions with a hot climate, metal structures are heated to high temperatures and subjected to large temperature deformations. The greatest complexity and labor intensity is the assembly of sheet structures.

Assembly in these conditions is usually carried out in two stages: first, individual sheets are assembled on special stands and welded into mounting blocks, after which subsequent assembly is carried out. In order to reduce deformations and welding stresses during welding, it is performed in a certain sequence, depending on the length of the seam and the thickness of the structures being welded.

There are certain ways of protection against the negative effects of light and heat radiation. As a rule, sun protection devices are used in combination with various architectural techniques, as well as means of protection against excessive solar radiation. Before starting construction work, it is necessary to take into account the location of buildings and windows relative to the sides of the horizon, the natural features of the landscape, it is also necessary to paint architectural elements in light colors and to select building materials with reflective or light-absorbing properties. Sun protection systems are divided into two types: internal and external. The internal ones include: curtains (classic, roll-up, Roman), blinds. Outdoor systems include: canopies and awnings, facade and exterior blinds, architectural structures in the form of decorative canopies.

In areas of seismic activity, special seismic measures are taken during the design and construction of buildings and structures. Such measures, taking into account the peculiarities of the foundation soil and structural solutions of buildings, are being developed for both underground and above-ground parts of objects under construction. To use the soil as a basis for the construction of foundations, methods of complete or partial elimination of subsidence properties of the soil and methods of complete or partial cut of the soil are used.

In seismically dangerous areas, in order to avoid subsidence properties of soils, the foundation is buried below the freezing level. A mandatory stage is the waterproofing of the foundation and the organization of drainage systems on the territory of the construction site. There are also ways to improve the soil by mechanical and physic-chemical methods. Mechanical ones include ramming of the soil, compaction with piles or soil-cement supports and the device of sand pillows. Physic-chemical methods include exposure to the soil with the help of high temperatures; cement, clay and salt solutions; organic substances and strengthening with the help of the process of silicatization.

Difficulties also arise during construction in wetlands. The first thing worth noting here is the inconvenience of the construction process itself: there is nowhere to unload and store the material, there is nowhere for workers to live, it is difficult to move around the construction site. The peculiarity of marsh soils is their tendency to deformation, instability due to a large number of fine-grained particles, a high degree of moisture saturation. Improper construction in swampy areas can lead to flooding of the house during heaving of the soil, the appearance of cracks in the load-bearing walls and rapid destruction of the building due to illiterate distribution of the load on the ground, constant dampness indoors due to increased humidity of the floor covering.

Before building a foundation on swampy soil, it is necessary to familiarize yourself with its features relative to ordinary land. Soil elements, such as sand or loam, are looser, subject to water filling and swelling. Such soil properties cause instability of the soil, which affects the instability of the structure installed on it. High humidity leads to the gradual destruction of traditional supports, so building a house in such conditions requires more money and labor.

  When building a foundation in a swampy area, it is necessary to increase the flexibility of the structure, as well as to reduce the pressure on the support. This is achieved through the use of foundation types designed specifically for swampy terrain. It is also necessary to increase the area of support on the ground due to concrete slabs or other devices. It is necessary to use piles or high supports in the presence of high humidity and high degree of soil freezing. The lighter and more flexible the material, the better the foundation design will be.

There is a certain technology of construction in wetlands. Wells with a depth of 5 to 10 meters are drilled at the corners of the planned foundation. If a brick structure is planned, then the well should be deep, if a wooden structure is planned, then 5-6 meters will be enough. At the bottom of the well, soil indicators are measured with a probe. The freezing point of the soil, reservoir levels and depth, and the composition of groundwater are taken into account. If the peat layer is small, then it can be removed manually by getting to the clay and sandstone.

On such a soil, the foundation will stand steadily. In the case of a large amount of peat, there are several options: to carry out drainage, which will require time and effort, or to put the house on piles. Pile foundation is a suitable option for "difficult" soil. After preparing the foundation, a house is built from any convenient material. In the conditions of a peat bog, the most difficult and costly stage to implement is laying the foundation.

Summing up the above, we would like to say that construction work in areas with special climatic conditions is characterized by great complexity and increased costs for resources of all kinds. This is due not only to the specifics of the spatial planning and design solutions of the objects being built, but also to the negative impact of climatic, geophysical and organizational factors on the technology and organization of construction work.

References:

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2. Larukova Irina. How to make the foundation of a house in a swamp — 2022. [electronic resource] — Access mode. — URL: https://geostart.ru/post/1066
3. Martemyanov A.I. Design and construction of buildings and structures in seismic regions. — 1985 — 145 p.
4. Peter Sergeev. Which foundation is best to build on marshy soil — 2020. [electronic resource] — Access mode. — URL: https://proekt-sam.ru/fundamenty/fundament-na-bolotistoy-pochve.html
5. Shevchenko L. P.  Architecture and climate of the Southern Russian region. — 1996 — 73 p.