scholarly journals NEW ASPECT AT THE USE OF FIBERGLASS IN THE CONSTRUCTION OF INDUSTRIAL CHIMNEYS

2021 ◽  
Vol 6 (10) ◽  
pp. 17-24
Author(s):  
V. Shaposhnikov ◽  
N. Privezenov
Keyword(s):  
Reinforced Concrete ◽  
Thermal Insulation ◽  
Monolithic Lining ◽  
Temperature Fields ◽  
Concrete Lining ◽  
Construction Technology ◽  
Construction Time ◽  
Steel Mesh ◽  
The Difference ◽  
Traditional Construction

The change in the operational characteristics of reinforced concrete chimneys with a monolithic lining when changing the traditional construction technology is considered. The difference between the traditional and proposed technology is the replacement of the separating element of the concrete lining and the supporting concrete of the chimney trunk. Traditionally, when installing industrial pipes with a monolithic lining, both with the use of sliding formwork and lifting-adjustable, with almost simultaneous laying of two types of concrete, a steel mesh is used as a separating layer. It is proposed to replace the steel mesh with fiberglass with a heat-insulating coating. Thermal insulation of the "Bronya" type is considered as a multilayer thermal insulation coating. The work presents a comparative analysis of changes in the distribution of temperature fields along the chimney wall during the introduction of this technology on the example of the chimney of the Krasnoyarsk CHPP-1 h=275 m. It is proved that the replacement of steel mesh with fiberglass with a heat-insulating coating improves the physical and chemical characteristics of the structure and provides a more efficient thermal operation of the chimney. The use of this technology will also improve the organization of construction production, reduce construction time and costs, reduce the material consumption of chimney structures and the complication of work on its construction, reduce the possibility of defects and destruction. Therefore, the introduction of the proposed technology will increase the reliability and lifespan of the structures of industrial reinforced concrete chimneys with a monolithic lining

scholarly journals Influence of house bearing construction rigidi-ty of precast reinforced concrete on stress-strain state Continuous Flight Auger (CFA) piles foundations

2020 ◽  
pp. 48-57
Author(s):  
Viktor Nosenko ◽  
Oleg Krivenko
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Residential Buildings ◽  
Precast Concrete ◽  
Relative Deformation ◽  
Construction Time ◽  
Stress Strain ◽  
Stress Strain State ◽  
Basement Floor ◽  
The Difference

At present, the tendency to build multi-storey residential buildings has become widespread in Ukraine. This is due to a number of reasons: significant increase in land prices in cities, dense urban development and the availability of appropriate equipment for the construction of such structures. One of the most common materials for multi-storey buildings is monolithic reinforced concrete. The main advantage of monolithic structures is the possibility of free spatial planning and the possibility of uniform redistribution of forces in the elements of the frame - the house works as one rigid entire structure. On the other hand, such structures require a long construction time and appropriate highly qualified control of monolithic works. Therefore, as an alternative, prefabricated reinforced concrete structures are used to accelerate the pace of construction. In this work, the influence of the rigidity of a precast reinforced concrete house on the stress-strain state of CFA piles foundation is investigated. The stress-strain state of a precast reinforced concrete building with two basement options is analyzed: precast and monolithic.                                                 The numerical modeling of the interaction of the system elements is used as a research method: soil base - foundation - aboveground structure. It was found that the replacement in a prefabricated house only one basement floor of precast concrete on a monolithic one affects the redistribution of forces, so the self-supporting wall is loaded 2.6 times, and the busiest wall, which rests on both sides of the floor slab, is unloaded to 2.1 times.  It was found that in the case of a basement made of precast reinforced concrete with a precast basement the difference efforts in pile heads (under the load-bearing walls) can differ 1.98 times, and in the case of a monolithic one 1.17 times. So it is mean, the monolithic foundation redistributed of efforts between the piles is more uniform. It is established that the monolithic reinforced concrete basement, in comparison with the prefabricated one, reduces the uneven settlement of the foundation by 2.4 times. When designing large-panel houses, it is advisable to provide a basement floor monolithic - this will allow to load the fundamental constructions more evenly, which in its reduction reduces the relative deformation of buildings and reduces their cost.

scholarly journals Innovative construction technology for the development of urban space

2018 ◽  
Vol 170 ◽  
pp. 01104
Author(s):  
Oksana Kurakova
Keyword(s):  
Reinforced Concrete ◽  
Urban Space ◽  
Negative Impact ◽  
Organizational Management ◽  
Time Frame ◽  
Construction Technology ◽  
Concrete Technology ◽  
Construction Time ◽  
Concrete Construction ◽  
Labor Resources

The use of innovative technologies in construction contributes to the development of the urban environment. Reduction of construction time allows more intensive development of the territory, as well as to reduce the period of inconvenience to citizens associated with construction. Such intensification is possible due to the development of organizational and technological concepts aimed at reducing the time of finished products output while ensuring their high quality and efficient use of all types of resources involved in the construction process. So, the achieved results in the field of introduction of continuous-flow type of operation, reducing work labor input and increasing the intensity of labor have created a high potential for cast-in-place construction of buildings at a speed comparable with the use of prefabricated reinforced concrete technology. Despite this, the analysis of various situations connected with the cast-in-place reinforced concrete construction has shown that in most cases, the actual investment period completion dates for such projects take much longer than planned. This fact has a very negative impact on the cost of construction. A characteristic feature of the cast-in-place reinforced concrete construction is the circumstance that such a situation can be observed even at an advanced level of organizational management when the conditions for the continuity of supplies of materials, highly mechanized work and the scheduled provision of the production process with qualified labor resources are held. The comprehensive analysis conducted during the research of the organization of construction showed that an essential drawback of modern approaches to the organizational management in the case of cast-in-place construction is the excessive conservatism of methods that does not ensure the proper speed of making managerial decisions in the event of deviations in execution of certain works. The author conducted and presents an analysis of the factors influencing the efficiency of high-rise construction. Зresented directions of further actions to improve the efficiency of construction and reduce its time frame.

scholarly journals Non-Destructive Testing of Technical Conditions of RC Industrial Tall Chimneys Subjected to High Temperature

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2027 ◽  
Author(s):  
Marek Maj ◽  
Andrzej Ubysz ◽  
Hala Hammadeh ◽  
Farzat Askifi
Keyword(s):  
Reinforced Concrete ◽  
Thermal Insulation ◽  
Concrete Cover ◽  
Temperature Fields ◽  
Shear Stresses ◽  
Destructive Testing ◽  
Reinforced Concrete Chimney ◽  
Strong Action ◽  
Internal Forces ◽  
Non Destructive

Non-destructive tests of reinforced concrete chimneys, especially high ones, are an important element in assessing their condition, making it possible to forecast their safe life. Industrial chimneys are often exposed to the strong action of acidic substances, They are negatively exposed to the condensation of the flue gases. Condensate affects the inside of the thermal insulation and penetrates the chimney wall from the outside. This is one reason for the corrosion of concrete and reinforcing steel. Wet thermal insulation settles, and drastically reduces its insulating properties. This leads to an increase in temperature in the reinforced concrete chimney wall and creates additional large variations in temperature fields. This consequently causes a large increase in internal forces, which mainly increase tensile and shear stresses. This results in the appearance of additional cracks in the wall. The acid condensate penetrates these cracks, destroying the concrete cover and reinforcement. Thermographic studies are very helpful in monitoring the changes in temperature and consequently, the risk of concrete and reinforcement corrosion. This simple implication between changes in temperature of the chimney wall and increasing inner forces as shown in this article is particularly important when the chimney cannot be switched off due to the nature of the production process. Methods for interpreting the results of thermovision tests are presented to determine the safety and durability of industrial chimneys.

scholarly journals Application of temporary reinforcement technology in insufficient construction of the understructure bearing capacity of viaduct

2019 ◽  
Vol 136 ◽  
pp. 04080
Author(s):  
Guohui Cao ◽  
Reqiang Liu ◽  
Jing Liu ◽  
Xiang Gao ◽  
Peng Wang
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Social Benefits ◽  
Construction Technology ◽  
Project Cost ◽  
Special Cases ◽  
Project Construction ◽  
Lower Structure ◽  
Traditional Construction

The complex three-dimensional traffic construction often occur when the lower structure cannot bear the construction load and other special cases, indicating the need for temporary reinforcement of the lower structure. In this paper, combined with a project construction example, various temporary reinforcement technologies are adopted to solve the insufficient bearing capacity during understructure construction, which poses a serious danger, to ensure synchronous construction of the understructure and viaduct. Compared with the traditional construction technology, the temporary reinforcement technology proposed in this paper features the advantages of saving project cost and time and has achieved better economic and social benefits.

Experimental Study of Bending Toughness on Hybrid Fiber Reinforced Concrete

2013 ◽  
Vol 327 ◽  
pp. 201-204
Author(s):  
Jin Song Shi ◽  
Bo Yuan ◽  
Da Zhang Wang ◽  
Zhe An Lu
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Toughness Index ◽  
The Difference ◽  
Loading Methods ◽  
Index Value

In order to investigate the difference of current toughness index standards for fiber reinforced concrete, two main groups of specimens were made to take bending toughness test with the requirements of corresponded standards, loading methods and loading speeds, which are ASTM C1018 in America, ACI 544 and JSCE G552 in Japan. United with software Origin, the load-deflection curves gathered from bending test was calculated with relative standards. The results show that the calculated toughness index value with ASTM C1018-98 in America is more accurate with three grades but the requested deflection of testing is much longer than others while ACI 544 and JSCE G552 in Japan are quite the contrary.

scholarly journals THE INFLUENCE OF THE METHOD OF LAYING PIPELINES ON THE ENERGY EFFICIENCY OF THE HEATING NETWORK

2019 ◽  
Vol 10 (2) ◽  
pp. 59-66
Author(s):  
E. A Biryuzova ◽  
A. S Glukhanov
Keyword(s):  
Energy Efficiency ◽  
Heat Loss ◽  
Thermal Insulation ◽  
Thermal Energy ◽  
Great Influence ◽  
Temperature Fields ◽  
Insulation Material ◽  
Design Work ◽  
Heat Networks ◽  
Insulation Thickness

Through pipelines of heat networks, due to their large length, a large amount of thermal energy is lost. Identification of technical solutions related to improving the energy efficiency of heating networks is an urgent task at present. The article is devoted to the consideration of options for laying pipelines of heat networks during design work. In the conducted studies, two main methods of underground laying of pipelines of heat networks with the choice of the most energy-efficient, with minimal losses of thermal energy are considered. Channel and channelless laying methods are investigated with the same design features and technological conditions of operation of pipelines of heat networks using the same thermal insulation material. For each option, the required thickness of the thermal insulation is determined by the normalized density of the heat flow, thermal calculations are performed to determine the heat loss and the value of the temperature fields generated around the operating pipelines of the heat networks. The obtained values of the thermal insulation thickness in the channel method of laying pipelines are 30-50 % lower than those in channelless laying. The heat loss values, according to the results of the heat calculation for the options under consideration, in the channel method of laying are reduced by 47-65 %. The temperature fields formed around the pipelines of thermal networks with channelless laying significantly exceed the natural value of the soil temperature at the depth of the pipeline. What has a great influence on the determination of the distance to adjacent pipelines and other utilities, laid underground, in the zone of the thermal network. A comparative analysis of the results obtained makes it possible to single out the choice of the method of laying the pipeline into a group of measures aimed at energy saving and increasing energy efficiency in heating systems.

scholarly journals OBJECTS OF TRANSPORT INFRASTRUCTURE: EXPERIENCE OF SCIENTIFIC SUPPORT IN CONSTRUCTION WITHIN THE “QUALITY” CONCEPT IMPLEMENTATION

2019 ◽  
Vol 16 (5) ◽  
pp. 618-634
Author(s):  
I. S. Pulyaev ◽  
S. M. Pulyaev
Keyword(s):  
Reinforced Concrete ◽  
Building Materials ◽  
Concrete Structures ◽  
Economic Feasibility ◽  
Transport Infrastructure ◽  
Building Structures ◽  
Construction Technology ◽  
Scientific Support ◽  
Free Construction ◽  
Modern Building

Introduction. The paper deals with the issues related to the implementation of the “quality” concept in the construction of reinforced concrete transport facilities linked with the scientific support during design and construction. Nowadays this problem particularly relevant in the context of the modern construction solutions, combined with the need to obtain the required properties of concrete structures and ensure the economic feasibility of construction. The aim of the research is to generalize and systematize the main methods and techniques of concrete works, which minimize the defects and cracks while the construction of transport infrastructure.Materials and methods. On the example of different technologies used in the Russian construction over last 10 years, the authors demonstrated the developed methods of obtaining high quality concrete products taking into account tested and proved modern building materials.Results. The results of the research formed the basis of the projects, technological regulations for the production, specifications and standards of organizations, guidelines. Moreover, the results also allowed implementing the concept of “quality” in transport construction based on obtaining defect-free reinforced concrete structures with specified properties, taking into account the use of modern building materials.Discussion and conclusions. The research allows carrying out construction of various massiveness and extent. The obtained results form the basis of construction technology of other industrial and civil construction objects with reinforced concrete application. The paper is interesting and useful for specialists in providing defect-free construction of reinforced concrete building structures, for engineering and technical staff. The authors dedicate the research to the memory of Professor and Doctor of Technical Sciences, A.R. Solovyanchik (1938-2019).

Analysis of New Construction Materials and its Development

2012 ◽  
Vol 204-208 ◽  
pp. 4119-4123
Author(s):  
Bo Wang ◽  
Ji Cheng ◽  
Xiao Han Zhang
Keyword(s):  
Thermal Insulation ◽  
Construction Materials ◽  
Insulation Materials ◽  
New Construction ◽  
Wall Materials ◽  
Basic Concepts ◽  
Countermeasures And Suggestions ◽  
Traditional Construction ◽  
Sealing Materials

New construction materials are the new generations of construction materials which are on the basis of the traditional construction materials, including the new wall materials, thermal insulation materials, water sealing materials, decoration materials and etc. New construction materials industry is developed with the deeply reforming and opening of China. This paper introduces the basic concepts and characters of the new construction materials, analyzes the development and application of the new construction materials, and then discusses countermeasures and suggestions of the development of the new construction materials.

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