CONDITIONAL ASSESSMENT SYSTEM FOR REINFORCED CONCRETE MARINE STRUCTURES – A CASE STUDY

2021 ◽  
Vol 162 (A4) ◽  
Author(s):  
R K Vanama ◽  
B Ramakrishnan ◽  
K Balasubramanian ◽  
S Patil
Keyword(s):  
Reinforced Concrete ◽  
Assessment System ◽  
Tidal Range ◽  
Marine Structures ◽  
Damage Level ◽  
Condition Rating ◽  
Marine Structure ◽  
Cr System ◽  
Non Destructive

Current study mainly focusses on the development of a conditional assessment system for reinforced concrete structures present in marine environment demonstrating with a case study of cargo berths (CB) at Deendayal Port Trust, Kandla, Gujarat, India. The maximum tidal range at the study area is nearly 8m, making the field non-destructive tests (NDT) challenging. The proposed assessment system is based on the damage level classification (DLC) of structure, evaluated by a set of widely used NDTs. The study further investigates the usage of DLC system in comparison with the Condition Rating (CR) method developed by Verma et al. NDTs were conducted at 182 locations between CB 7-10 and observed that the condition of the marine structure, indicated by CR system and DLC system is similar irrespective of their different test approaches. The proposed DLC assessment system is reliable, quick, efficient and requires relatively lesser efforts compared to the CR system.

Conditional Assessment System for Reinforced Concrete Marine Structures – A Case Study

2020 ◽  
Vol 162 (A4) ◽  
Author(s):  
R K Vanama ◽  
B Ramakrishnan ◽  
K Balasubramanian ◽  
S Patil
Keyword(s):  
Reinforced Concrete ◽  
Assessment System ◽  
Tidal Range ◽  
Marine Structures ◽  
Damage Level ◽  
Condition Rating ◽  
Marine Structure ◽  
Cr System ◽  
Non Destructive

Current study mainly focusses on the development of a conditional assessment system for reinforced concrete structures present in marine environment demonstrating with a case study of cargo berths (CB) at Deendayal Port Trust, Kandla, Gujarat, India. The maximum tidal range at the study area is nearly 8m, making the field non-destructive tests (NDT) challenging. The proposed assessment system is based on the damage level classification (DLC) of structure, evaluated by a set of widely used NDTs. The study further investigates the usage of DLC system in comparison with the Condition Rating (CR) method developed by Verma et al. NDTs were conducted at 182 locations between CB 7-10 and observed that the condition of the marine structure, indicated by CR system and DLC system is similar irrespective of their different test approaches. The proposed DLC assessment system is reliable, quick, efficient and requires relatively lesser efforts compared to the CR system.

Assessment of a cracked reinforced concrete supporting structure for a converter in a steel melting shop through non-destructive testing and a statistical approach – a case study

2020 ◽  
Vol 62 (11) ◽  
pp. 633-641
Author(s):  
D Das ◽  
S R Debbarma ◽  
D Bouri ◽  
S Banerjee ◽  
S Chatterjee
Keyword(s):  
Reinforced Concrete ◽  
Crack Depth ◽  
Critical Conditions ◽  
Test Sequence ◽  
Steel Melting ◽  
Test Results ◽  
Scientific Review ◽  
Supporting Structure ◽  
Non Destructive

The subject of this paper is the occurrence of cracks and other types of damage, such as delamination of the reinforcement cover, carbonation, porosity, etc, which have occurred in a reinforced concrete supporting structure for a converter in a steel melting shop in India. The structure consists of two thick reinforced concrete walls on which the converter rests. Converters are used in a steel melting shop for blowing oxygen through hot metal and steel is produced through a reaction with carbon, silicon, phosphorus, sulphur, etc. A scientific review of the existing non-destructive test methods is carried out with reference to this case study and critical features of the testing process are described, which will help site engineers to correctly devise the test sequence and analysis procedure for assessment of the structures in specific critical conditions. Crack depth is estimated by analysing test results based on the ultrasonic pulse velocity. The paper explains how appropriate selection of the method and basic parameters is essential for estimating the most accurate crack depth. Lack of understanding of the existing condition of the material of the structure may lead to an incorrect interpretation of the test results. Further to this, a simple statistical procedure is described to identify significant cracks without detailed testing. The repair methodology and its specific features are also discussed in this paper. This case study on the assessment of the converter supporting structure will help engineers to provide solutions for similar types of damaged structure found in industry.

scholarly journals Corrosion at low moisture content in both carbonated and chloride polluted concrete – Villa E-1027, a case study

2019 ◽  
Vol 289 ◽  
pp. 10007
Author(s):  
Elisabeth Marie-Victoire ◽  
Myriam Bouichou
Keyword(s):  
Reinforced Concrete ◽  
Moisture Content ◽  
Cultural Heritage ◽  
Environmental Conditions ◽  
Electrochemical Measurements ◽  
Corrosion Activity ◽  
Definition Of ◽  
Ancient Monuments ◽  
Non Destructive

Corrosion in reinforced concrete is generally attributed to either carbonation or chloride presence in the vicinity of the bars. But in the field of cultural heritage, especially for the most ancient monuments, it is not rare to encounter both carbonated and chloride polluted concrete, inducing heavy corrosion, as was the case in the Villa E-1027 in Roquebrune-Cap-Martin, on the French Mediterranean seashore. The villa was designed by Eileen Gray and Jean Badovici between 1926 and 1929. Due to aggressive environmental conditions and a period of dereliction, the concrete of the villa was quite heavily decayed and a deep restoration was led between 2000 and 2006. But after a little more than 10 years, and despite active maintenance, the villa is again facing corrosion induced decay. Prior to the definition of a new restoration protocol, to better evaluate the corrosion activity, in 2017 a permanent monitoring of moisture and temperature both in the air and in the concrete was installed. In the meantime, a series of instant electrochemical measurements was performed from 2017 to 2018. A first analysis of the results of the monitoring and the non-destructive tests clearly evidences that probably due to the conjunction of the carbonation of the concrete and external active chloride pollution, corrosion can happen at quite low moisture content.

Failure Analysis Case Study of a 1.5 Meter Space Flex Harness

2017 ◽  
Author(s):  
Erick Kim ◽  
Kamjou Mansour ◽  
Gil Garteiz ◽  
Javeck Verdugo ◽  
Ryan Ross ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Field Of View ◽  
Area Of Interest ◽  
Air Stream ◽  
Novel Method ◽  
Temperature Controlled ◽  
Non Destructive ◽  
Failure Site

Abstract This paper presents the failure analysis on a 1.5m flex harness for a space flight instrument that exhibited two failure modes: global isolation resistances between all adjacent traces measured tens of milliohm and lower resistance on the order of 1 kiloohm was observed on several pins. It shows a novel method using a temperature controlled air stream while monitoring isolation resistance to identify a general area of interest of a low isolation resistance failure. The paper explains how isolation resistance measurements were taken and details the steps taken in both destructive and non-destructive analyses. In theory, infrared hotspot could have been completed along the length of the flex harness to locate the failure site. However, with a field of view of approximately 5 x 5 cm, this technique would have been time prohibitive.

scholarly journals Case study on the mineralogical and petrophysical analysis of reinforced concrete slabs of a highway viaduct of the S.G.C. Orte-Ravenna

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Elena Marrocchino ◽  
Chiara Telloli ◽  
Alessandra Aprile ◽  
Domenico Capuani ◽  
Davide Malaguti ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slabs ◽  
Petrophysical Analysis ◽  
Reinforced Concrete Slabs

Vibration control of network-based offshore structures subject to earthquakes

2021 ◽  
pp. 014233122110259
Author(s):  
Hua-Nv Feng ◽  
Bao-Lin Zhang ◽  
Yan-Dong Zhao ◽  
Hui Ma ◽  
Hao Su ◽  
...  
Keyword(s):  
Sufficient Conditions ◽  
Offshore Structures ◽  
Delay Systems ◽  
Linear Matrix ◽  
Seismic Responses ◽  
Marine Structures ◽  
Damping Control ◽  
Marine Structure ◽  
Uncertain Model ◽  
Control Scheme

Marine structures are inevitably influenced by parametric perturbations as well as multiple external loadings. Among these loadings, earthquake is generally more destructive and unpredictable than others. It is significant to develop effective active control schemes to guarantee the safety, stability, and integrity of marine structures subject to earthquakes and parametric perturbations. In this paper, the problem of networked [Formula: see text] robust damping control is addressed to stabilize a marine structure subject to earthquakes. First, in consideration of perturbations of the structure parameters, an uncertain model of the networked marine structure under earthquakes is presented. Second, a robust networked [Formula: see text] control scheme is presented to suppress seismic responses of the structure. By using stability theory of time-delay systems, several sufficient conditions on robust stability of the networked marine structure system are obtained, and the linear matrix inequality methods are utilized to solve the gain matrix of the controller. Finally, simulation indicates that compared with the traditional robust [Formula: see text] control and the proposed networked [Formula: see text] control, the seismic responses amplitudes of the marine structure under the two controllers are almost the same, while the latter is more economic than the former.

scholarly journals Non-destructive handheld XRF study of archaeological composite silver objects—the case study of the late Roman Seuso Treasure

2021 ◽  
Vol 13 (5) ◽  
Author(s):  
Viktória Mozgai ◽  
Bernadett Bajnóczi ◽  
Zoltán May ◽  
Zsolt Mráv
Keyword(s):  
Fluorescence Analysis ◽  
The Body ◽  
High Quality ◽  
X Ray ◽  
Composite Objects ◽  
Mechanical Attachment ◽  
Non Destructive ◽  
Made In ◽  
Late Roman

AbstractThis study details the non-destructive chemical analysis of composite silver objects (ewers, situlas, amphora and casket) from one of the most significant late Roman finds, the Seuso Treasure. The Seuso Treasure consists of fourteen large silver vessels that were made in the fourth–early fifth centuries AD and used for dining during festive banquets and for washing and beautification. The measurements were systematically performed along a pre-designed grid at several points using handheld X-ray fluorescence analysis. The results demonstrate that all the objects were made from high-quality silver (above 90 wt% Ag), with the exception of the base of the Geometric Ewer B. Copper was added intentionally to improve the mechanical properties of soft silver. The gold and lead content of the objects shows constant values (less than 1 wt% Au and Pb). The chemical composition as well as the Bi/Pb ratio suggests that the parts of the composite objects were manufactured from different silver ingots. The ewers were constructed in two ways: (i) the base and the body were made separately, or (ii) the ewer was raised from a single silver sheet. The composite objects were assembled using three methods: (i) mechanical attachment; (ii) low-temperature, lead-tin soft solders; or (iii) high-temperature, copper-silver hard solders. Additionally, two types of gilding were revealed by the XRF analysis, one with remnants of mercury, i.e. fire-gilding, and another type without remnants of mercury, presumably diffusion bonding.

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