scholarly journals CALCULATION AND DESIGN OF BUILDING STRUCTURES CONSIDERING THE VARIATION OF THE STRUCTURE, SECTIONS AND DIFFERENTIATION OF THE CONSTRUCTION CHARACTERISTICS OF MATERIALS

2021 ◽  
pp. 6-31
Author(s):  
L. R. Mailyan ◽  
S. A. Stel'makh ◽  
E. M. Shcherban'
Keyword(s):  
Reinforced Concrete ◽  
Future Research ◽  
Building Structures ◽  
Calculation Methods ◽  
Design Standards ◽  
Steel Reinforced Concrete ◽  
Reinforcing Fibers ◽  
Margin Of Safety ◽  
Concrete Elements ◽  
Comprehensive Study

Statement of the problem. The increasing volumes of construction require new technological, structural and design solutions for reinforced concrete elements. Centrifugation, being a promising production technology, leads to variatropic - differing in their characteristics (density, strength, deformability, etc.) in the section of concretes and structures made of them. In many cases, this must be taken into account in the calculation and design, but such studies have practically not been carried out. Therefore, when calculating and designing building structures of a variatropic structure, an unreasonably large margin of safety is usually laid, which leads to their strong rise in price. In the design standards and scientific literature, there are no theoretical and practical methods for calculating centrifuged reinforced concrete building structures, taking into account the variability of the structure and characteristics of concrete over the section. Separate data have confirmed the efficiency of centrifugation, but it is not yet possible to fully use its advantages due to the lack of accounting for structure variability in existing calculation methods. Results and conclusions. As a result of the review and analysis, the vectors of development and directions of future research have been identified, which consist in studying the work of steel-reinforced concrete centrifuged and vibro-centrifuged compressed elements using fiber-reinforcing fibers. It is proposed to improve the manufacturing technology and calculation methods for a complete and comprehensive study of such an undoubtedly interesting and unique phenomenon as the variatropy of the structure of concrete of building structures.

Calculation and Design of Building Structures Given the Variatropy of the Structure, Sections and Differentiation of Constructive Characteristics of the Materials

2021 ◽  
pp. 27-48
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Design Guidelines ◽  
Future Research ◽  
Building Structures ◽  
Reinforcing Fibers ◽  
Concrete Building ◽  
Margin Of Safety ◽  
Concrete Elements ◽  
Comprehensive Study

Состояние проблемы. Возрастающие объемы строительства требуют новых технологических, конструктивных и расчетных решений железобетонных элементов. Центрифугирование, являясь перспективной технологией производства, приводит к вариатропным, т. е. различающимся по своим характеристикам (плотности, прочности, деформативности и др.), по сечению бетонам и конструкциям, выполненным из них. Это во многих случаях необходимо учитывать в расчете и проектировании, однако исследований касательно этой темы практически не проводилось. Поэтому при расчете и проектировании строительных конструкций вариатропной структуры обычно закладывается необоснованно большой запас прочности, что приводит к их сильному удорожанию. В нормах проектирования и научной литературе отсутствуют теоретические и практические методы расчета центрифугированных железобетонных строительных конструкций с учетом вариатропности структуры и характеристик бетона по сечению. Отдельными данными подтверждена эффективность центрифугирования, но в полной мере использовать его преимущества из-за отсутствия в существующих методах расчета учета вариатропности структуры пока невозможно. Результаты и выводы. В результате обзора и анализа определены векторы развития и направления будущих исследований, заключающиеся в изучении работы сталежелезобетонных центрифугированных и виброцентрифугированных сжатых элементов с использованием фиброармирующих волокон. Предполагается совершенствовать технологию изготовления и методики расчета для еще полного и всестороннего исследования такого уникального явления, как вариатропия структуры бетона строительных конструкций. Statement of the problem. Increasing numbers of construction call for new technological, structural and design solutions for reinforced concrete elements. Being a promising production technology, centrifugation causes variatropic characteristics, i. e., differing ones (density, strength, deformability, etc.), in cross section of concrete and structures made of them. This is oftentimes essential to consider in both calculation and design, but research on this topic is literally non-existent. Thus while calculating and designing building structures of the variatropic structure, an unreasonably large margin of safety is commonly present leading a surge in their price. In design guidelines and scientific literature there are no theoretical and practical methods of calculation of centrifuged reinforced concrete building structures considering the variability of the structure and characteristics of concrete in cross section. Some data confirm the efficiency of centrifugation, but it is not yet possible to make complete use of its advantages due to the lack of existing methods for calculating the variability of the structure. Results and conclusions. Based on the review and analysis, the vectors of development and directions of future research are identified, which are to sinvestigate the operation of reinforced concrete centrifuged and vibrocentrifuged compressed elements using fiber reinforcing fibers. It is suggested that the manufacturing technology and calculation methods are improved for a more complete and comprehensive study of such a unique phenomenon as variatropy of the concrete structure of building structures.

TO CALCULATION OF STEEL-REINFORCED CONCRETE RIBBED PLATES FOR REFURBISHED FLOORS

2021 ◽  
Vol 97 (5) ◽  
pp. 3-15
Author(s):  
F.S. ZAMALIEV ◽  
◽  
A.G. TAMRAZYAN ◽  
◽  
Keyword(s):  
Reinforced Concrete ◽  
Internal Stresses ◽  
Design Standards ◽  
Steel Reinforced Concrete ◽  
Economical Design ◽  
Bridge Structures ◽  
Composite Section ◽  
Current Design ◽  
Calculation Results ◽  
Concrete Elements

Analyzes national experience of restoring the old buildings floors. An assessment of the wood-reinforced concrete using experience, steel-reinforced concrete floor structures and methods for calculating load-bearing elements of a composite section is given. It is noted that the current design standards and existing methods for calculating steel-reinforced concrete structures of civil buildings and bridge structures use simplified calculation methods and do not reflect the actual stress-strain state of a bent element, do not take into account the initial pre-operational deformations and stresses, and do not lead to economical design solutions. Sometimes they lead to incorrect results. Expressions of internal moments and forces of steel-reinforced concrete bending elements are presented from the equilibrium conditions of a composite element, taking into account pre-operational forces. The results of our own experiments are presented, where it is shown that during the hardening of concrete, beams and slabs receive deformations in the form of reverse deflection (bending), and internal stresses arise in the sections of steel-reinforced concrete elements. Formulas are given for calculating the deflections of bending elements taking into account their initial deformations. To compare the calculation results of the proposed method for calculating steel-reinforced concrete elements, taking into account the initial deformations and stresses, the data of our own experiments were used and comparisons were given. Satisfactory convergence of the results is shown.

scholarly journals Analyzing of Coatings on Steel - Reinforced Concrete Elements by Mobile NMR

2016 ◽  
Vol 62 (1) ◽  
pp. 65-82 ◽  
Author(s):  
J. Orlowsky
Keyword(s):  
Reinforced Concrete ◽  
Potential Effect ◽  
Building Site ◽  
Steel Reinforced Concrete ◽  
Mobile Nmr ◽  
The Individual ◽  
First Time ◽  
Concrete Elements ◽  
Non Destructive

Abstract A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.

scholarly journals MODELS OF BAY REINFORCED CONCRETE ELEMENTS RESISTANCE AT ACTION OF CYCLE PERMANENT SIGN HIGH LEVEL FORCES

2018 ◽  
Vol 1 (50) ◽  
pp. 112-123 ◽  
Author(s):  
V. M. Karpiuk ◽  
A. I. Kostiuk ◽  
Yu. A. Somina
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Physical Models ◽  
Cyclic Loads ◽  
Longitudinal Reinforcement ◽  
Calculation Methods ◽  
Cyclic Action ◽  
High Level ◽  
Creep Deformations ◽  
Concrete Elements

The reinforced concrete span beam structures work with small, middle and large shear spans under the action of cyclic loads of high levels is investigated. It is established that researches of physical models development of bending reinforced concrete elements fatigue resistance to the cyclic action of transverse forces and calculation methods on its base are important and advisable due to following features of said load type: the nonlinearity of deformation, damage accumulation in the form of fatigue micro- and macrocracks, fatigue destruction of materials etc. The key expressions of the concrete endurance limits definition (objective strength), longitudinal reinforcement, anchoring of longitudinal reinforcement, which consists the endurance of whole construction are determined. Also the role and the features of influence of vibro-creep deformations on the change mechanics of stress-strain state of concrete and reinforcement of research elements are investigated.

Bearing Capacity of Common and Damaged CFRP-Strengthened R. C. Beams Subject to High-Level Low-Cycle Loading

2019 ◽  
Vol 968 ◽  
pp. 185-199
Author(s):  
Vasyl M. Karpiuk ◽  
Yulia A. Syomina ◽  
Diana V. Antonova
Keyword(s):  
Bearing Capacity ◽  
Repeated Loading ◽  
Calculation Methods ◽  
Design Standards ◽  
Deformation Method ◽  
Current Design ◽  
Cycle Loading ◽  
High Level ◽  
Concrete Elements

In the course of operation or armed hostilities the span r.c. structures are subject to substantial damage and considerable reduction of their bearing capacity, especially under low-cycle repeated loading. In this connection it becomes necessary to renew their operation capacity and/or improve their bearing capacity. However, the current design standards contain no recommendations as to determination of the residual bearing capacity of such structures and calculation of their reinforcement. There are methods of the operation capacity renewal and reinforcement of the structures by increasing their sections adding metal or reinforced concrete elements. Still, the calculation methods of such reinforcement are also imperfect. It is proposed to renew operation capacity of such structures by strengthening their tensioned parts with CFRP; the performed experimental research will provide the basis for calculating bearing capacity of said structures with the aid of the deformation method improved by the authors.

Study on Ductility Performance of T-Shaped Section Steel Reinforced Concrete Columns

2013 ◽  
Vol 351-352 ◽  
pp. 359-362 ◽  
Author(s):  
Xin Wang
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Future Research ◽  
Repeated Loading ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Element Analysis ◽  
Steel Reinforced Concrete ◽  
Mechanics Characteristic ◽  
Shaped Section

This paper, the mechanics characteristic of T-shaped section steel reinforced concrete column under low period repeated loading by using large-scale finite element analysis software ABAQUS was analyzed, combined existing research, the influence of the performance of ductility under different steel ratio and axial compression ratio was studied, we concluded that the T-shaped section steel reinforced concrete column has the very good ductility performance, and put forward the axial compressive ratio limit under the different parameters, and to provide the reference for future research and application.

RESULTS OF EXPERIMENTAL RESEARCH OF REINFORCED CONCRETE BEAMS RESISTANCE IN THE ZONE OF SHEAR BENDING

2017 ◽  
Vol 7 (4) ◽  
pp. 25-31
Author(s):  
Valery B. FILATOV ◽  
Vladislav O. GORYNTSEV ◽  
Valery P. BINDER
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Longitudinal Section ◽  
Reinforced Concrete Beams ◽  
Calculation Methods ◽  
Design Standards ◽  
Testing Data ◽  
Failure Loads ◽  
Experimental Values ◽  
Shear Bending

The results of an experimental study of the strength and stress-strain state of reinforced concrete beams in the zone of shear bending are presented. The study was carried out on samples with a small percentage of longitudinal section reinforcement. The technique of testing, data on the rigidity and crack resistance of test specimens under loading, the nature of their destruction are presented. Comparison of experimental values of failure loads with calculated values obtained by the methods of domestic and foreign design standards is performed. It is shown that the empirical basis of the calculation methods limits the range of satisfactory correspondence between the calculated and experimental values of the strength of inclined sections of reinforced concrete beams under the action of shear forces. The conclusion is made about the need to improve the design models to ensure the constructive safety of design solutions.

Application Technology of Bamboo Reinforced Concrete in Building Structure

2012 ◽  
Vol 195-196 ◽  
pp. 297-302 ◽  
Author(s):  
Wei Feng Zhao ◽  
Jing Zhou ◽  
Guo Bin Bu
Keyword(s):  
Reinforced Concrete ◽  
Weight Ratio ◽  
High Strength ◽  
Concrete Columns ◽  
Building Structures ◽  
Structural Elements ◽  
High Tensile Strength ◽  
Application Technology ◽  
Steel Bar ◽  
Concrete Elements

Bamboo is mainly a tropical and subtropical plant which is found adequate in many countries. The strength of bamboo as concrete reinforcement is much lower than steel bar reinforcement. However, one of the merits is a cheap and replenishable agricultural resource and abundantly available. Due to excellent properties like high strength to weight ratio, high tensile strength and free-cutting and processing, bamboo as a potential reinforcement material in place of steel is widely available in concrete structural elements. The present paper introduces some of the existing studies and application technology of bamboo reinforced concrete elements in building structures, such as bamboo reinforced concrete columns, beams, slabs and walls.

scholarly journals Directions of Convergence of the Requirements of the Main Domestic Standard for the Design of Concrete and Reinforced Concrete Structures SP 63.13330.2012 with the Requirements of the International Standard ISO 19338

2019 ◽  
pp. 93-98
Author(s):  
Sergey B. Krylov ◽  
Ravil S. Sharipov ◽  
Sergey A. Zenin ◽  
Yury S. Volkov
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
National Standards ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Design Standards ◽  
Structural Concrete ◽  
International Standard ◽  
Assessment Requirements

Design standards on building structures should contain, first of all, the performance and assessment requirements of structures. At the same time, design standards should provide the possibility for design and construction of concrete and reinforced concrete parts of buildings and structures that meet the requirements of the Technical regulations "On the safety of buildings and structures". Taking into account the importance of ensuring the reliability and safety of buildings and structures erected with the use of structural concrete, the technical Committee of the international organization for standardization ISO TC 71 "Concrete, reinforced concrete and prestressed concrete", certifies national standards for compliance with the requirements of the international standard ISO 19338 "Performance and Assessment Requirements for Design Standards on Structural Concrete", developed by the same Committee. The standard describes the issues that should be included in the standards for the design of concrete and reinforced concrete structures (terms and definitions, basic requirements, performance requirements,loads and impacts, design estimates, requirements for manufacturing and construction, as well as quality control). These requirements are common to all standards in the design of concrete and reinforced concrete structures. In this regard, it is relevant and important to establish the possibility of presenting the National Code of rules SP 63.13330.2012 "SNiP 52.01-2003 Plain and Reinforced Concrete Structures. General Provisions" for certification for compliance with the requirements of ISO 19338. To achieve this goal, the relevant work has been done, based on the results of which were made the proposals for the submission of SP 63.13330.2012 for certification for compliance with ISO 19338:2014. These proposals are set out in the text of the article.

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