scholarly journals Experimental Study on the Relationship between the Natural Frequency and the Corrosion in Reinforced Concrete Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Liye Zhang ◽  
Limin Sun ◽  
Lijuan Dong
Keyword(s):  
Reinforced Concrete ◽  
Natural Frequency ◽  
Structural Damage ◽  
Concrete Beams ◽  
Polynomial Model ◽  
Reinforced Concrete Beams ◽  
Frequency Change ◽  
Corrosion Depth ◽  
The Relationship ◽  
Corrosion Time

Due to many nondamage factors such as temperature, humidity, carbonation, and corrosion effects on natural frequency, the key problem of the application frequency-based method to detect damage is to reveal the rules of these factors affect natural frequency and further to eliminate their effects. The long-term characteristics of reinforced concrete structures require a lot of attention, especially in corrosive environment. In this paper, an experimental investigation was conducted to study the deflection and natural frequency of reinforced concrete beam in a marine environmental chamber for six corrosion stages (accelerated corrosion for 0, 20, 40, 70, 100, and 140 days). The experimental results demonstrated that deflection increases with corrosion time, while natural frequency decreases with corrosion time. Based on the accelerate corrosion test data of reinforced concrete beams, the general expression of the relationship between corrosion depth and natural frequency has been established through the fitting curve method. The polynomial model has been selected for establishing the relationship between steel corrosion depth (including the main reinforcement and stirrup) and natural frequency. The reason for selecting the polynomial model is that the sum of squares due to error (SSE) is closer to 0 and the coefficient of multiple determination (R-square) is closer to 1. This investigations help to discriminate the cause of reinforced concrete beams natural frequency change, to eliminate nondamage factors affects, and to apply many structural damage identification methods effectively.

ACOUSTIC EMISSION BEHAVIOUR OF OVER-REINFORCED CONCRETE BEAMS

2019 ◽  
pp. 4-12 ◽  
Author(s):  
V. V. Bardakov ◽  
A. I. Sagaydak ◽  
S. V. Elizarov
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Cyclic Load ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Reinforced Concrete Beams ◽  
Emission Data ◽  
Point Bend ◽  
Destructive Processes ◽  
The Relationship

The paper presents the results of the conducted experimental studies on three-point bend testing of over-reinforced concrete beams with incremental cyclic load, up to destruction, using the acoustic emission method. In total 3 RC beams differ from each other in reinforcement type, concrete composition and ultimate load were tested. Special attention is paid to the investigation of the relationship between destructive processes occurring during the testing of reinforced concrete beams and the evolution of acoustic emission data registered during the test. The analysis described in the article makes it possible, on the basis of acoustic emission data, recorded during the tests, to distinguish the stages corresponding to the different technical state of over-reinforced concrete structures.

Effect of concrete carbonation on natural frequency of reinforced concrete beams

2016 ◽  
Vol 20 (3) ◽  
pp. 316-330 ◽  
Author(s):  
Liye Zhang ◽  
Limin Sun
Keyword(s):  
Reinforced Concrete ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
Physicochemical Process ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Accelerated Carbonation ◽  
Concrete Carbonation ◽  
Damage In Concrete

We carried out an experimental investigation to study the influence of concrete carbonation on the natural frequency of simply supported reinforced concrete beams. A total of 10 reinforced concrete test beams and 12 concrete-carbonation test specimens were subjected to different accelerated carbonation stages for 0, 7, 14, 21, and 28 days. Modal tests were performed on reinforced concrete test beams after the accelerated carbonation stages. In order to reduce the effect of other factors on the modal tests, constant temperature, relative humidity, and boundary conditions of the test beams were maintained in the experimental process. The experimental results show a trend of the natural frequencies of reinforced concrete test beams to decrease with the increase in concrete-carbonation depths. With statistical analyses of experimental data, this study established the relationship between concrete-carbonation depths and natural frequencies. Fitting lines for the drop in natural frequencies and carbonation depths are obtained for the first four modal frequencies. Based on the analysis of the physicochemical processes of concrete carbonation, the main reason behind the drop in natural frequencies is the increase in mass after concrete carbonation. The percentage composition of increase in mass after complete carbonation is obtained based on the analysis of the physicochemical process. This analysis demonstrates part of the reason for the drop in natural frequencies and proves that the experimental results are reliable and credible. This study provides further insight into the use of modal parameters to assess damage in concrete structures in structural health monitoring.

Strain Mode Damage Detection in Reinforced Concrete Beams Application

2012 ◽  
Vol 446-449 ◽  
pp. 566-571
Author(s):  
Jia Quan Wu ◽  
Ji Yao ◽  
Hong Yan Li ◽  
Liang Cao ◽  
Kun Ma
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Damage Detection ◽  
Structural Damage ◽  
Concrete Beams ◽  
Element Model ◽  
Reinforced Concrete Beams ◽  
Strain Mode ◽  
Finite Element Software ◽  
Injury Models

This paper describes the strain mode damage detection theory and a three-dimensional reinforced concrete beams finite element model was built by finite element software. The different degree injury models tests were compared. Experiment’s results show that the first four natural frequencies of different degree injury models are small differences while the corresponding strain modes have a significant changed in damage location. The structure of the strain mode changes are still evident when structural damage occurred in the strain mode node.

scholarly journals THE ANALYSIS OF CRACKS IN BEAMS OF QUAY NO. 80A AT KLAIPEDA PASSENGER AND CARGO TERMINAL

2018 ◽  
Author(s):  
Raimondas SADZEVICIUS ◽  
Vincas GURSKIS ◽  
Tatjana SANKAUSKIENĖ ◽  
Vitas DAMULEVIČIUS ◽  
Virginija GURSKIENĖ
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beams ◽  
Shrinkage Strain ◽  
Reinforced Concrete Beams ◽  
Concrete Mixture ◽  
Concrete Shrinkage ◽  
Number Of Factors ◽  
Mixture Class ◽  
The Relationship

The cracks can be technological, appear during the usage time of construction, they can also be regular, and appear under the design load or they can also be unexpected and appear due to accidental impacts. Our research has shown that the cracks have appeared in reinforced concrete beams of the superstructure in quays No. 80 and 81 after the construction of Klaipeda Passenger and cargo terminal are caused by shrinkage strain, when the reinforced concrete beams has hardened. Normal hardening concrete shrinkage deformation is inevitable, but it depends on a number of factors, in particular, that in the present structures occurred because: - W/C ratio of concrete mixture exceeds the allowable values; - coarseness of selected aggregates (D = 16 mm) are too small for the construction of a massive wall; - concrete stratification and possible lack of care for hardening concrete (ambient temperature, etc.), this segregation could be affected by to big spread of concrete mixture (class of slump S3). The crack width at reinforced concrete beams in the superstructure of quay No.80 varies from 0.05 to 0.5 mm. This are a non-structural cracks, so they do not reduce significantly the mechanical strength and stability of the structure. Also, research has shown that the relationship between the crack width and the distance between the cracks is weak. Proposals for elimination of potential causes of cracking are presented according to the results.

scholarly journals Analysis of the microcracking process with the Acoustic Emission method with respect to the service life of reinforced concrete structures with the example of the RC beams

2015 ◽  
Vol 63 (1) ◽  
pp. 55-63 ◽  
Author(s):  
B. Goszczyńska ◽  
G. Świt ◽  
W. Trąmpczyński
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Structural Damage ◽  
Crack Width ◽  
Crack Formation ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Acoustic Emission Method ◽  
Emission Method

Abstract The study presents the analysis of the process of crack formation and crack width growth in statically determinate and hyperstatic reinforced concrete beams with the IADP acoustic emission method. The beams were subjected to the monotonic, variable with unloading, and variable cyclic loading schemes. The criteria of structural damage were established to account for the structure durability

Classification of Damage Mode of Reinforced Concrete Beams Using Acoustic Emission Technique

2012 ◽  
Vol 626 ◽  
pp. 953-957 ◽  
Author(s):  
Md Noor Noorsuhada ◽  
Ibrahim Azmi ◽  
Norazura Muhamad Bunnori ◽  
Mat Saliah Soffian Noor ◽  
Mohd Saman Hamidah ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Shear Crack ◽  
Reinforced Concrete Beams ◽  
Damage Mode ◽  
Rc Beams ◽  
Static Test ◽  
The Relationship

Classification of damage modes in reinforced concrete (RC) beams was studied. Acoustic emission (AE) monitoring in conjunction with static test was applied on RC beams. The damage modes were classified by based on the load-deflection curve, the relationship between load and damage modes and the intensity analysis. It can be concluded that six damage modes were identified; namely micro-cracking, localized crack propagation, flexural crack distribution, shear crack formation, damage localization and failure of the beam. The use of intensity chart clearly estimates the zones of the damage mode of the reinforced concrete beams.

Sign in / Sign up

Export Citation Format

Share Document