Construction and Geotechnics

Object of research is safety of works at height on air-lines of communication and overhead power transmission lines. Security measures at rise and performance of work on support are analysed air-lines of communication and overhead power transmission lines. It is necessary to apply systems of safety of works to safety of works at height which enter: anchor device; a leash (for an insurance and positioning); a connecting and shock-absorbing subsystem (slings, ropes, carbines, shock-absorbers, a security measure from falling of polzunkovy type on the flexible or rigid anchor line). At rise on a support by means of a ladder, claws or manholes for safety of works safety systems need to be fixed for the top part, by means of anchor devices. Now the top part of support of air-lines of communication and power lines in the Russian Federation isn't equipped with rigid anchor points for fastening of safety systems. Therefore fastening is possible only by means of flexible anchor lines. Installation of such lines on the top end of a support not always technically is also economically possible and convenient for safety of works at height. Therefore at construction new and reconstruction of the existing communication lines and electricity transmissions it is necessary to establish on support rigid anchor points for fastening of safety systems. From the technical point of view the anchor device is simple (it can be some hooks on diameter of a support) therefore its prime cost will be small and introduction won't have considerable impact on expenses on construction and reconstruction of support. However will allow to ensure safety of works at height.

Retaining structures are prevalent constructions, which are used due to dense urban development areas nowadays. Today it has wide spread in using reinforced soil in these constructions. This technology is to improve the properties of an existing of the soil on the construction site by introducing the elements of increased strength into the ground. The reinforcement counteracts the loads and, thereby, to create a more economical design. In modern construction practice, as reinforcement, geosynthetics hold the leading role for the retaining structures. However, in spite of its extensive using, the operation of the retaining walls has not been explored yet, and, therefore, it needs in additional researches. The article presents the plan of the series of experiments to investigate the operation of retaining construction, which is reinforced with different types of geosyntetics. Geotextile, geocell and geodon are as reinforced layers. The test program was developed, the order of conducting experiments was described, and the matrix of experiment planning was presented. Materials and equipment, which are necessary for experiment, were described in details. Except laboratory, it is supposed to perform numerical experiments, which are necessary for exception errors in laboratory tests and for comparison of indications. Numerical simulations are expected to be performed using the finite elements method in the software package PLAXIS 2D, which can to interpret the actual conditions of the retaining wall. Numerical simulation is similar to the program of laboratory tests. In addition, the article presents conclusions about the relevance of experiments and their originally.

This article is about the problem of reconstruction and modernization of residential five-storey buildings constructed in 1960-70s. The total area of the buildings built in the country during that period counts around 290 million sq.m., that is almost 10 % of the housing stock. Many of those houses have floors made of concrete and seldom-worn load carrying structures, but they don’t satisfy modern requirements and are in need of comprehensive overhaul. Reconstruction of houses is one of the most important directions in solving the housing problem. The maximum increase of housing stock can be achieved by accretion and addition of one or several storeys. The expences on material resources for creation the engineering infrastructure decreases on 25-40 %. Such methods of reconstruction are especially effective in the central areas of major cities as the cost of the real estate 1 m² is high enough. Reconstruction in those areas is the most attractive and promising for investors. There are ways of reconstruction of five-storey buildings, with the transfer of load from addition of the building to new foundation. An example of the reconstruction of the five-storey residential building in Moscow at Khimkinskiy Boulevard, 4. Five-storey building of I-515 serie, built in 1965. From economic point of view on this example, we can conclude the reconstruction of the building with accretion and addition of storeys is appropriate, cause the cost of apartment after the reconstruction is 40 % higher than the cost before it, but less than the cost of an apartment in a new building.

In this article participants’ of construction main risks are considered, such as risks of investor (dishonesty of developers, increase of interest rates for the credits, management of investments for long term, etc.); risks of developer (cessation the supply of investments, insufficient quality of the building and assemble work performed by contracting organizations, mistakes in project and working documentation, etc.); risks of general project contractor (overdue payments, insufficient qualification of workers, etc.); risks of designer (documentation could be not accepted by the customer, dishonesty of the customer, etc.). The main ways of these risks' decrease are considered: insurance of risks, choosing of contractor and developer by the competitive basis, organization of money reserve, monitoring procedure behind use of money, application of penalties, conducting control of contract organizations and observance by workers' technical safety, etc. The analysis of methods of risks' assessment is submitted. Such as an expert method (it is based on opinion of experts, who are estimating the risks). It doesn’t required the calculations application and the additional software. Method of the analysis of expenses' relevance: stage-by-stage investment in construction allows taking necessary measures at the first signs of risks’ increase. Method of analogies (comparison of the investment project with similar projects, visually represents consequences of unaccounted risks). The analysis of project's sensitivity of the defines as far as variable indicators of efficiency of the project at fluctuations of basic data will change, the most adverse factors of the investment project are defined. The analysis of scenarios of projects' development (it is supposed that all variables of indicators of projects' efficiency change at the same time, deviations of parameters are counted taking into account their correlation). The analysis of economic crises of 2008 and 2014 is made by using these parameters: collapse of prices of oil, depreciation of ruble, the crisis reasons, growth rates of inflation, delay of growth rates of GDP, transaction of purchase and sale in the market of real estate, the cost of square meter.

In the modern world is gaining momentum density of development in already established neighborhoods. Insolation is the major factor rendering the health impact on the human environment. The calculation of insolation is an integral part of project documentation. The solution to the problem of sun exposure in a dense urban environment will serve as a well-planned apartments and living rooms in them. Another way of solving this problem is the increase in light, but this implies another problem - the more aperture, the more energy and resources and therefore costs will need to heat the room. Energy and insolation are closely related to each other. Each year the reserves of natural resources decrease, and there is a new problem, how to make buildings and facilities more energy efficient. In different countries there are different approaches to solving this problem. This article discusses the most inexpensive method and does not create major inconveniences of the builders. Consider the option, as the reduction of window openings to an acceptable size, to reduce heat loss and thereby reduce the consumption of heating. Gives calculations showing what effect can be achieved when reducing the size of the window openings. It is proved that the reduction of the window opening no effect on critical insolation habitable rooms.

The problem of increased cost of electricity has caused the recent trend towards the construction of energy efficient buildings. In addition, there is the problem of rational use of resources. This article discusses one way to increase the energy efficiency of buildings through the use of renewable energy sources. These sources include traditional wind, water, sun, earth (geothermal). Geothermal energy is of two types - high-grade and low-grade. The article discussed in detail ground low potential energy for heating buildings. The basic methods of extraction low potential energy of the soil. Such methods include the use of heat exchangers of horizontal and vertical type. In this paper we detail the horizontal heat exchangers. These include surface heat exchangers and energy basket. Surface heat exchanger consists of tubes laid parallel to the ground. Energy baskets - heat exchangers, which shall be laid in the ground vertically to a depth of 5 meters and represent the individual contours of the pipe, coiled in a spiral. Consider the basic structure, sequence, and editing features, the main advantages of these systems. Resulting from the energy systems considered can not be used directly. Therefore, it is advisable to use heat pumps, which raise the temperature level to the desired value. Further energy can be used for heating, hot water and electricity for air conditioning and building.

The article presents the results of the analysis of the effect of vibration exposure pile driving on the existing foundations of a functioning oil and gas complex located in Tengiz city. The aim of the tests (vibration monitoring) was to determine the smallest allowable distance piling devices excluding the impact of vibration on the foundation and ensuring the safe operation of the plant. The article presents the results of vibration exposure piling at different distances from the base, taking into account the natural oscillations of technological processes, solid foundation and others, as well as the results of excitation of ground mass at various distances from the source of vibration exposure (pile driving). The source of the vibration excitation was pile driving (С16-40) through pile-driving equipment Banut 555 with a mass of hydraulic hammer 6,075 tonnes and a maximum drop height 1.0 m. In case of driving of piles was drawn up the statement of pile-driving. Vibromonitoring was carried out by the instrument Profound VIBRA +, with use of the 3D seismic sensors. The interval of measurement of vibration was carried out every 5 seconds. Tests were executed according to requirements of norm of DIN 4150-3 according to which the most allowed level of vibration is equal 5,00 mm/sec. (from 0-10 Hz). The maximum impact on a soil array was recorded at a distance 40 m from a source in case of driving of piles No. 3, 5 and 6. In all cases the maximum values of speed of oscillations were recorded when dipping C16-40 piles on depth from 5 to 8 m.