Impact-Echo Methods to Assessment Corrosion of Reinforced Concrete Structures

2014 ◽  
Vol 627 ◽  
pp. 268-271 ◽  
Author(s):  
Kristýna Šamárková ◽  
Zdeněk Chobola ◽  
Daniela Štefková ◽  
Ivo Kusák
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Signal Analysis ◽  
Damping Factor ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Nacl Solution ◽  
Frequency Signal ◽  
Impact Echo ◽  
Dominant Frequencies

The aim of this paper is to evaluate the corrosion of reinforced concrete structure. To assess the state of corrosion we used frequency signal analysis, where we observed the changes in dominant frequencies and growth of damping factor λ. Tension pulse was produced in axis of the rod at one end and detected in axis at opposite end of rod. Diameter of steel rod was 8 mm. The article presents the results of measurements obtained during 24 months controlled degradation in aqueous NaCl solution.

The Corrosion Status of Reinforced Concrete Structure Monitoring by Impact-Echo Method

2014 ◽  
Vol 875-877 ◽  
pp. 445-449 ◽  
Author(s):  
Kristýna Šamárková ◽  
Zdeněk Chobola ◽  
Daniela Štefková
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Structure ◽  
Response Signal ◽  
Nacl Solution ◽  
Impact Echo ◽  
Structure Monitoring ◽  
Impact Echo Method ◽  
Dominant Frequencies

The paper deals with the study of dominant frequencies of an Impact-Echo method response signal obtained from a reinforced concrete beam with a steel rod diameter of 8 mm. Tension pulse was produced in axis of the rod at one end and detected in axis at opposite end of rod. Dominant frequencies of the response signal will be the main criterions for the reinforced concrete rebar corrosion progress. The article presents the results of measurements obtained after 12 months controlled degradation in aqueous NaCl solution. The results were compared with measurements of electrical resistance of reinforcing steel by using the Thomson double bridge.

scholarly journals Modeling Blast Loading on Buried Reinforced Concrete Structures with Zapotec

2008 ◽  
Vol 15 (2) ◽  
pp. 137-146 ◽  
Author(s):  
Greg C. Bessette
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Explosive Charge ◽  
High Explosive ◽  
Concrete Structures ◽  
Blast Loading ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Solution Approach ◽  
Coupling Algorithm

A coupled Euler-Lagrange solution approach is used to model the response of a buried reinforced concrete structure subjected to a close-in detonation of a high explosive charge. The coupling algorithm is discussed along with a set of benchmark calculations involving detonations in clay and sand.

Fuzzy uncertainty and its applications in reinforced concrete structures

2020 ◽  
Vol 18 (5) ◽  
pp. 1175-1191
Author(s):  
Utino Worabo Woju ◽  
A.S. Balu
Keyword(s):  
Reinforced Concrete ◽  
Material Properties ◽  
Concrete Structure ◽  
Concrete Structures ◽  
Fuzzy Relation ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Intermediate Grades ◽  
Content Type ◽  
Degree Of Membership

Purpose The aim of this paper is mainly to handle the fuzzy uncertainties present in structures appropriately. In general, uncertainties of variables are classified as aleatory and epistemic. The different sources of uncertainties in reinforced concrete structures include the randomness, mathematical models, physical models, environmental factors and gross errors. The effects of imprecise data in reinforced concrete structures are studied here by using fuzzy concepts. The aim of this paper is mainly to handle the uncertainties of variables with unclear boundaries. Design/methodology/approach To achieve the intended objective, the reinforced concrete beam subjected to flexure and shear was designed as per Euro Code (EC2). Then, different design parameters such as corrosion parameters, material properties and empirical expressions of time-dependent material properties were identified through a thorough literature review. Findings The fuzziness of variables was identified, and their membership functions were generated by using the heuristic method and drawn by MATLAB R2018a software. In addition to the identification of fuzziness of variables, the study further extended to design optimization of reinforced concrete structure by using fuzzy relation and fuzzy composition. Originality/value In the design codes of the concrete structure, the concrete grades such as C16/20, C20/25, C25/30, C30/37 and so on are provided and being adopted for design in which the intermediate grades are not considered, but using fuzzy concepts the intermediate grades of concrete can be recognized by their respective degree of membership. In the design of reinforced concrete structure using fuzzy relation and composition methods, the optimum design is considered when the degree of membership tends to unity. In addition to design optimization, the level of structural performance evaluation can also be carried out by using fuzzy concepts.

Research on Factors Affecting Durability and Improvements for FRP Reinforced Concrete Structures

2011 ◽  
Vol 189-193 ◽  
pp. 847-852 ◽  
Author(s):  
Lei Tan ◽  
Xi Jun Liu ◽  
Ming Qiao Zhu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Civil Engineering ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Factors Affecting ◽  
Related Research ◽  
Durability Of Concrete ◽  
At Home

With wide applications of FRP in civil engineering, it is necessary to study the durability of FRP reinforced concrete structure. Based on the related research both at home and abroad, the factors affecting durability of FRP reinforced concrete structures and the corresponding improvements have been put forward by analyzing the durability of concrete, FRP materials and reinforced structures, respectively.

Calculation Models of the Bearing Capacity of Span Reinforced Concrete Structure Support Zones

2019 ◽  
Vol 968 ◽  
pp. 209-226
Author(s):  
Vasyl M. Karpiuk ◽  
Yulia A. Syomina ◽  
Diana V. Antonova
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Cross Sections ◽  
Concrete Structure ◽  
Strain State ◽  
Complex Stress ◽  
Deformation Analysis ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure

Experience gained in design, erection and operation of span reinforced concrete structures has proved that practically all of them are subject to complex stress-strain state. At that, the researchers pay considerable greater attention to calculation of strength, deformation analysis and determination of crack resistance in normal cross-sections than to calculation of their support zones, including oblique sections, which results are generally taken into account for determining the section dimensions and the quantity of the cross reinforcement.

Performance Analysis of Reinforced Concrete Structures Strengthened with BFRP

2013 ◽  
Vol 712-715 ◽  
pp. 966-969 ◽  
Author(s):  
Ze Bao Kan ◽  
Yan Ru Li
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Performance Analysis ◽  
Seismic Performance ◽  
Present Status ◽  
Concrete Structure ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure

The present status of reinforced concrete structure confined by FRP is introduced, and the recent technical researches of reinforced concrete beams and columns confined by BFRP are summarized. Based on those researches, the mechanical properties and calculation models are analyzed. At the same time, the seismic performance of reinforced concrete beams and columns confined by BFRP is also explored.

scholarly journals Grounds for the decision to strengthen reinforced concrete structures after short-term impulse loads, using Alluriquin HPP as an example

2019 ◽  
pp. 6-6
Author(s):  
Oleg Rubin ◽  
Anton Antonov ◽  
Sergey Lisichkin ◽  
Kirill Frolov ◽  
Andrey Lisichkin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Floor Slab ◽  
Concrete Floor ◽  
Removal Method ◽  
Load Removal ◽  
Impulse Load

Introduction. Floorings of the turbine hall and installation sites of the HPP (PSS) are one of the most important reinforced concrete structures, as during operation they are subjected to significant process duties, including those not provided for by the project. Thus, during the testing of crane equipment on the floor surface of the installation site of the Alluriquin HPP under construction, the cargo weighing 22 tons fell, under the influence of which the floor slab was punched, which required a comprehensive study of the condition of the reinforced concrete structure of the floor and the surrounding area of the failure of structures, as well as the development of measures to strengthen the damaged structure. Materials and Methods. Visual and instrumental studies of the stress and strain state (SSS) of the reinforced concrete structure of the turbine hall slab and surrounding structures were carried out with the use of optical devices (MPB-3 reading microscope), Schmidt hammer to determine the strength of concrete structures, as well as the “reinforcement load removal” method to determine the actual stresses in the reinforcement of structures. Results. The punching of the reinforced concrete floor of the installation site with vertical displacements of the edges of through cracks up to 12 mm, as well as the system of cracks formed during the fall of cargo was revealed. The actual stresses in the reinforcement are determined by the “reinforcement load removal” method. On the basis of finite element modeling the actual condition of structures during the period of cargo fall and after the removal of the load is obtained. On the basis of the analysis of results of field and design studies the schematic diagram of strengthening of structures by carbon composite materials is developed. Conclusions. The actual SSS of the reinforced concrete floor of the installation site and its support structures during the period of the cargo fall and after the termination of the impulse load is established. The vertical displacement of the edges of the crack of the floor punching was 17.5 mm during the period of the fall of the load and 12 mm after the removal of the impulse load. Crack opening width in reinforced concrete structures in the cargo drop area reached 2 mm. At the moment when the cargo fell on the floor slab, the values of stresses in the reinforcement cage reached 200 MPa; after the impact — 76.2 MPa. With a view of the subsequent safe operation of the reinforced concrete floor and surrounding structures the basic schemes of their strengthening by external reinforcement on the basis of carbon fiber have been developed, which have been proved by calculation.

THE USE OF DAMPER SYSTEMS IN BUILDINGS WITH REINFORCED CONCRETE STRUCTURES

2019 ◽  
Vol 7 ◽  
pp. 912-919
Author(s):  
Naima Ezzaki ◽  
Daniel Stoica ◽  
Laurentiu Rece ◽  
Amelitta Legendi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Elastic Field ◽  
Structural Safety ◽  
Reinforced Concrete Structures ◽  
Alternative Possibility ◽  
Structural Elements ◽  
Reinforced Concrete Structure ◽  
Linear Elastic ◽  
Safety Enhancement

This study aims to emphasize, by means of a comparative study, the efficiency of some damper systems as modern variants of consolidation / seismic structural safety enhancement used for buildings with reinforced concrete structure designed and erected according to the P13-type standards (from 1963) and considering this as an alternative possibility instead of retrofitting with reinforced concrete jackets (with significant implications for most of the structural elements at all levels of buildings). Damper devices are elements that can be easily replaced later in case of damage. Case studies were made, based on structural calculations in the linear elastic field, using the ETABS program.

Reliability Evaluation of Reinforced Concrete Structures of the Fuzzy Evaluation Model

2011 ◽  
Vol 255-260 ◽  
pp. 123-127
Author(s):  
Jian Qiang Chen ◽  
Wen Bo Li ◽  
Jin Huan Zhao
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Evaluation Model ◽  
Reliability Evaluation ◽  
Reinforced Concrete Structures ◽  
Fuzzy Evaluation ◽  
Reinforced Concrete Structure ◽  
Structure Reliability ◽  
Comprehensive Judgment ◽  
Fuzzy Evaluation Model

Based on the fuzzy manthematics theory,two-grade fuzzy comprehensive judgement used in reinforced concrete structure reliability appraisal is studied, the fuzzy comprehensive appraising model of structure reliability is founded. The paper supplies a fuzzy evaluation model for reinforced concrete fuzzy comprehensive judgment from qualitative analyze to quantificational analyze.

scholarly journals Design of reinforced concrete slabs subject to the construction joints

Vestnik MGSU ◽  
2019 ◽  
pp. 1106-1120
Author(s):  
Andrei V. Deineko ◽  
Valentina A. Kurochkina ◽  
Irina Yu. Yakovleva ◽  
Aleksandr N. Starostin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Construction Joint ◽  
Floor Slabs ◽  
Deformation State ◽  
Stress Deformation ◽  
Construction Joints

Introduction. When erecting monolithic reinforced concrete floor slabs, a necessity of construction joints arises. The construction joints are the areas of structural weakening. The construction practice shows that the compliance with the correct technology of the construction joint arrangement is not a sufficient condition to ensure the strength balance of reinforced concrete floor slabs. As a result, the stress-deformation state calculated on the assumption of the concrete slab solidity deviates from the actual state. The relevance of the task is determined by the fact that the conformity of design and actual characteristics of the in-situ reinforced concrete structures as a whole depends on the correct calculations of construction joints. Materials and methods. The problem of implementing the construction joints in the monolithic floor slabs was considered by way of example of a residential building under construction. In the course of construction, pre-construction land surveys were carried out at the areas of the construction joint arrangement. Calculations of reinforced concrete structures using finite element method (FEM) were also performed. Results. As a result of the study, the actual deflections of the floor slabs were measured at the areas of the construction joints and FEM calculations were made on the same floor slabs, both those erected at once and those erected in stages subject to the construction joints. The difference between the calculated and actual deflections is conditioned upon the inaccurate conformity between the mathematical model and the real reinforced concrete structure, its erection and maintenance conditions. It should be noted that the deflection of horizontal reinforced concrete structures is only one of the stress-deformation state parameters that can be measured better than the others. It is shown that if the deflection of a real reinforced concrete structure does not correspond with the design estimation, the other stress-deformation state parameters will differ from the design estimation as well. Conclusions. The influence of joints can be taken into account in the scope of FEM computer-aided calculations with the explicit reproduction of the structure erection by pouring concrete, using engineering approach to the consideration of nonlinearity on the basis of the introducing reduction coefficients to the reinforced concrete effective modulus of elasticity. Solid composition modeling of reinforced concrete provides the best possibilities on taking all sorts of nonlinearity manifestations into consideration.

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