scholarly journals DETERMINATION OF THE TORSIONAL STIFFNESS OF A REINFORCED CONCRETE ELEMENTS IN A NORMAL CRACK

2021 ◽  
pp. 269-274
Author(s):  
T.N. Azizov ◽  
N.M. Sribniak ◽  
L.A. Tsyhanenko
Keyword(s):  
Reinforced Concrete ◽  
Torsional Stiffness ◽  
Concrete Elements

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 TO DETERMINATION OF THE CRACKING MOMENT FOR BENDING REINFORCED CONCRETE ELEMENTS WITH ACCOUNT OF PLASTIC DEFORMATIONS OF CONCRETE IN THE TENSION AREA

2018 ◽  
Vol 3 (3) ◽  
pp. 30-38
Author(s):  
О.В. Радайкин ◽  
Oleg Radaykin
Keyword(s):  
Reinforced Concrete ◽  
Deformation Model ◽  
Conventional Concrete ◽  
Class A ◽  
Standard Calculation ◽  
Plasticity Coefficient ◽  
Concrete Elements ◽  
Nonlinear Deformation Model ◽  
Good Agreement

At the standard calculation of the cracking moment for bending reinforced concrete elements the plasticity coefficient γ is normally used, which according to SP 63.13330.2012 is 35% less than in the old SNiP 2.03.01-84*. The question arises, what is the reason for such a noticeable difference and which of the methods gives more reliable results? This article seeks to answer this question. For this purpose the physical meaning of the coefficient γ was considered in detail, with the usage of a nonlinear deformation model of a normal section. A calculation formula for γ depending on an element’s reinforcement degree was obtained, which is valid for conventional concrete of B15-B35 class. A comparison of the calculated cracking moment according to the proposed method with experiments by the other authors was carried out. A good agreement of results was observed.

scholarly journals ASSESSMENT OF THE DEPTH AND RATE OF CORROSION IN STEEL REINFORCEMENT OF REINFORCED CONCRETE CULVERTS

2020 ◽  
Author(s):  
Alexandr Vasiliev ◽  
Svetlana Daškevič
Keyword(s):  
Reinforced Concrete ◽  
Protective Layer ◽  
Corrosion Damage ◽  
Steel Reinforcement ◽  
Operating Conditions ◽  
Protective Properties ◽  
Open Atmosphere ◽  
Concrete Elements ◽  
Corrosion State

Based on the results of many research years on concrete carbonisation: both immediately after manufacture (using heat-moisture treatment) and in reinforced concrete elements operated for the periods of various length (in an open atmosphere); the effect of carbonisation on the change in the protective properties of concrete in relation to steel reinforcement; for determination of the dependence of the corrosion state of steel reinforcement on the degree of concrete carbonisation in the area of steel reinforcement; the obtained regression dependences of the change (by time in the cross section) of the degree of concrete carbonisation of various classes in strength, – the analysis of the time of the onset of the boundary values of the degrees of concrete carbonisation (strength classes C12/15–C30/37) for the operating conditions of the open atmosphere was performed. Based on it, the regression dependences of the time variation of the depth of corrosion damage of steel reinforcement were construed (for fixed thicknesses of the concrete protective layer). The obtained nature of dependences made it possible to offer, in a general form, the regression dependences of the depth of corrosion damage and corrosion rate of steel reinforcement for concretes (strength classes C12/15–C30/37) for operating conditions in open atmosphere.

To Determination of Stresses in the Stretched Armature of Extracredly Compressed Elements in the Limit Condition

2019 ◽  
Vol 974 ◽  
pp. 556-563
Author(s):  
Evgeniy N. Peresypkin ◽  
Sergey E. Peresypkin
Keyword(s):  
Reinforced Concrete ◽  
Linear Dependence ◽  
Boundary Value ◽  
Limit State ◽  
Limit Condition ◽  
Equal Strength ◽  
Points Of View ◽  
Concrete Elements

The problem of determining stresses in a stretched reinforcement of inflexible eccentric-compressed reinforced concrete elements is considered when the height of the compressed zone in the limit state exceeds its boundary value corresponding to the condition of equal strength of the section. Instead of the generally accepted linear dependence of the stresses under consideration on the height of the compressed zone, an elliptic relationship more expedient from different points of view has been proposed.

Using Non-Destructive Methods for the Characterization of Concrete in Aggressive Environments

2015 ◽  
Vol 15 ◽  
pp. 62-70
Author(s):  
Khial Nassima ◽  
Rachid Mehaddene
Keyword(s):  
Reinforced Concrete ◽  
Financial Impact ◽  
Cement Matrix ◽  
Ion Concentrations ◽  
Time Required ◽  
Concrete Elements ◽  
Non Destructive ◽  
Destructive Methods

The durability of reinforced concrete structures is reduced by the chloride penetration and susceptibility of the reinforcement to chloride induced corrosion which is considered a critical physic-chemical case. As the financial impact of the phenomena is very important, it seems essential to determine it influence on strength of reinforced concrete elements subjected to aggressive environnement such us the presence of chlorides when exposed to marine environnement. As such, the determination of the ion concentrations of chlorides profile within the cement matrix is of major importance, it tool to estimate the time required by the chlorides to reach the reinforcements in sufficient quantity to depassivate the steel.

Ermittlung der Materialkennwerte der Bewehrung für die Bemessung von textilbewehrten Bauteilen/Determination of the material properties of the reinforcement for textile-reinforced- concrete elements

Bauingenieur ◽  
2017 ◽  
Vol 92 (06) ◽  
pp. 280-288 ◽  
Author(s):  
Sergej Rempel ◽  
Marcus Ricker
Keyword(s):  
Reinforced Concrete ◽  
Material Properties ◽  
Textile Reinforced Concrete ◽  
Concrete Elements

Für die Bemessung von textilbewehrten Bauteilen sind Materialkennwerte für die Bewehrung erforderlich. Die bisherigen Untersuchungen erfolgten nicht einheitlich und waren sehr aufwendig. Aus diesem Grund wurde ein standardisierter Faserstrangzugversuch entwickelt, mit dem alle erforderlichen Materialkennwerte ermittelt werden können. Hierbei sind lediglich Versuche an einem 160 mm langen Faserstrang notwendig, der aus der textilen Bewehrungsmatte herausgeschnitten wird. Ein Faserstrang besteht aus zusammengesetzten Rovings. Die Ergebnisse zeigen, dass die textile Bewehrung sich linear-elastisch verhält und die Werte der Bruchspannung näherungsweise normalverteilt sind. Diese Erkenntnisse werden genutzt, um die Bemessungsspannung und Bemessungsdehnung zu ermitteln sowie um den Teilsicherheitsbeiwert für die textile Bewehrung über eine Zuverlässigkeitsberechnung zu bestimmen.

Bearing Capacity Of Centrally Compressed Reinforced Concrete Elements Corrosion-Damaged As A Result Of Fire Exposure

2019 ◽  
pp. 35-39
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Protective Layer ◽  
Temperature Fields ◽  
Reinforced Concrete Column ◽  
The Cross ◽  
Concrete Elements ◽  
Technical Calculation

Determination of the bearing capacity of the elements damaged as a result of fire effect depends on the accuracy of the thermo-technical calculation. After this calculation, the distribution of the temperature field over the cross section of the element and the strength characteristics depending on it are determined. The temperature distribution over the cross section of the element depends on such parameters as heat capacity and thermal conductivity of parts of the section, the spatial position of the structure, its humidity. As part of this work, heat engineering calculations of the cross section of the reinforced concrete column were performed with various options of the cross section - with and without a protective layer, taking into account the thermal performance of all cross section components (reinforcement, concrete and corrosion) and excluding corrosion and reinforcement. Based on the obtained temperature fields, the bearing capacity and its percentage ratio were calculated. The main conclusion is that the bearing capacity of the centrally compressed corrosion-damaged elements is significantly influenced by the factor of separation of the protective layer of concrete, as well as thermal-technical characteristics of materials.

scholarly journals Damage Assessment of Reinforced Concrete Elements Due to Corrosion Effect Using Dynamic Parameters: A Review

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 425
Author(s):  
Ivan Duvnjak ◽  
Ivan Klepo ◽  
Marijana Serdar ◽  
Domagoj Damjanović
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Protective Layer ◽  
Continuous System ◽  
Future Research ◽  
Reinforced Concrete Structures ◽  
Dynamic Parameters ◽  
Determination Methods ◽  
Concrete Elements

Corrosion of reinforcement is one of the main problems related to the durability of reinforced concrete structures. This can cause cracks and a separation of the protective layer, as well as reducing strength and structural stiffness, which can result in numerous human casualties. Visual inspection is a standard method of assessing the condition of reinforced concrete structures whose limitations, such as time, interpretability, accessibility, etc., may affect its effectiveness. Therefore, damage determination methods based on dynamic parameters are becoming more and more prominent in the assessment of damage to reinforced concrete structures. The aim of this paper is to review the literature regarding the determination of corrosion of reinforcement by methods based on dynamic parameters, and to identify future research to develop a method that would detect corrosion problems in time through a continuous system of structural health monitoring.

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