AE Damage Assessment in the Bell Tower of the Turin Cathedral

2019 ◽  
Vol 817 ◽  
pp. 579-585
Author(s):  
Amedeo Manuello ◽  
Davide Masera ◽  
Alberto Carpinteri
Keyword(s):  
Damage Assessment ◽  
Structural Integrity ◽  
Cumulative Number ◽  
Height Ratio ◽  
Value Analysis ◽  
Integrity Assessment ◽  
Bell Tower ◽  
The Stability ◽  
Good Agreement

Historical churches, masonry towers and bell towers are structures subjected to high risk, due to their age, elevation and low base area on height ratio. In this work, an innovative monitoring technique for structural integrity assessment of historical buildings is reported. At the same time, the emblematic case study of the Turin Cathedral Bell tower is presented. The damage evolution in the tall masonry structure is described by the evaluation of the cumulative number of AE and by different parameters able to predict the time dependence of damage. In particular, since environmental disturbances have been minimized, and instrumental noises have been filtered out. The b-value analysis shows a downward trend to values compatible with the growth of localized macro-cracks at the base of the tower. These results seem to be in good agreement with the numerical analysis. Extension to longer monitoring periods and, later, investigation of different segments are strongly recommended to assess the stability of the monument.

scholarly journals Acoustic Emission Monitoring of the Turin Cathedral Bell Tower: Foreshock and Aftershock Discrimination

2020 ◽  
Vol 10 (11) ◽  
pp. 3931 ◽  
Author(s):  
Amedeo Manuello Bertetto ◽  
Davide Masera ◽  
Alberto Carpinteri
Keyword(s):  
Structural Integrity ◽  
Regional Scale ◽  
Acoustic Emissions ◽  
B Value ◽  
Masonry Building ◽  
Cumulative Number ◽  
Value Analysis ◽  
Integrity Assessment ◽  
Static And Dynamic Analysis ◽  
Bell Tower

Historical churches, tall ancient masonry buildings, and bell towers are structures subjected to high risks due to their age, elevation, and small base-area-to-height ratio. In this paper, the results of an innovative monitoring technique for structural integrity assessment applied to a historical bell tower are reported. The emblematic case study of the monitoring of the Turin Cathedral bell tower (northwest Italy) is herein presented. First of all, the damage evolution in a portion of the structure localized in the lower levels of the tall masonry building is described by the evaluation of the cumulative number of acoustic emissions (AEs) and by different parameters able to predict the time dependence of the damage development, in addition to the 3D localization of the AE sources. The b-value analysis shows a decreasing trend down to values compatible with the growth of localized micro and macro-cracks in the portion of the structure close to the base of the tower. These results seem to be in good agreement with the static and dynamic analysis performed numerically by an accurate FEM (finite element model). Similar results were also obtained during the application of the AE monitoring to the wooden frame sustaining the bells in the tower cell. Finally, a statistical analysis based on the average values of the b-value are carried out at the scale of the monument and at the seismic regional scale. In particular, according to recent studies, a comparison between the b-value obtained by AE signal analysis and the regional activity is proposed in order to correlate the AE detected on the structure to the seismic activity, discriminating foreshock, and aftershock intervals in the analyzed time series.

scholarly journals Residual Life Assessment of Electricity Pylons – A Case Study

2009 ◽  
Vol 413-414 ◽  
pp. 219-228 ◽  
Author(s):  
John R. Maguire
Keyword(s):  
Structural Integrity ◽  
Residual Life ◽  
Life Assessment ◽  
Original Design ◽  
Integrity Assessment ◽  
Specific Safety ◽  
Residual Life Assessment ◽  
Independent Assessment ◽  
Overhead Power Line

This case study describes a structural integrity assessment of a 220 kV overhead power line. The line comprises 70 pylons over a distance of approximately 30 km, predominantly in a valley location. The pylons are spaced at intervals of approximately 400 m and each pylon is approximately 32 m in height. The line was originally constructed in the 1950’s, approximately 50 years prior to the requested structural integrity assessment. This paper describes the independent assessment that was carried out. The review established site-specific safety factors at the time of original design and construction; at the time of the review (2007), accounting for the possible presence of the “Thomasstahl” steel; and in the future, at the anticipated end of pylon life (in 2012).

Structural Integrity Assessment for Various Failure Modes Using a Risk-Based Maintenance Method

2004 ◽  
Author(s):  
Hiroyuki Horikawa ◽  
Masaki Yoshikawa ◽  
Nobuo Takasu
Keyword(s):  
Failure Modes ◽  
Structural Integrity ◽  
Ground Deformation ◽  
Degradation Mechanism ◽  
Risk Level ◽  
Integrity Assessment ◽  
Evaluation Approach ◽  
Actual Damage ◽  
Maintenance Plan ◽  
Good Agreement

In this paper, a newly developed system called RBM (Risk-Based Maintenance) is presented. The system is used to describe the structural integrity of buried pipeline based on the index of risk that is defined in the product of the failure frequency and the consequence. Various failure modes corresponding to each degradation mechanism are included, and the estimation of failure probability that the external load exceeds the structure resistance is carried out. As the result of trial evaluation compared with the past earthquake incident, it is in good agreement with actual damage of pipeline subjected to liquefaction and large ground deformation. Furthermore, the system enables operators to maintain the structural integrity for service life by providing the most optimized maintenance plan according to the risk level. The features of the quantitative risk evaluation approach and the benefits of the developed RBM system as a means of structural integrity assessment are also discussed.

Integrity Assessment of Hot Bolting Tool

2016 ◽  
Author(s):  
Guomin Ji ◽  
Madjid Karimirad ◽  
Frank Klæbo ◽  
Per-Christian Irgens
Keyword(s):  
Structural Integrity ◽  
Stress And Strain ◽  
Test Results ◽  
Working Process ◽  
Integrity Assessment ◽  
Nonlinear Contact ◽  
Process Qualification ◽  
Different Dimensions ◽  
Good Agreement ◽  
Classification Society

Hot Bolting is the practice of removing and replacing or freeing and re-tightening bolts on live operating piping and equipment while the system is pressurized. It is potentially hazardous and the utmost caution needs to be exercised when planning and carrying it out. The hot bolting tools designed by Irgens Engineering AS aim to establish a safe barrier for flange connections during the hot bolting operation. Their application would extend the hot bolting operation, increase the safety and simplify the working process. Qualification of new hot bolting tools was carried out by the joint efforts of producer, operator and classification society. The paper addresses a part of the integrity assessment of the new hot bolting tools. The nonlinear finite element analyses were performed by ABAQUS for sequential loading during hot bolting operation under the temperature specified by operator and the nonlinear contact interactions between different components were taken into account in the analysis. In the present study, the structural integrity was investigated for 4″ class 1500 flange with ring gasket and class 150 flanges with IFG gasket of four different dimensions (1/2″, 1.5″, 3″, and 8″). The gasket stress and strain as well as contact pressure of the gasket were studied to investigate the possible leakage. The test was performed for 4″ class 1500 flange with ring gasket by Irgens Engineering AS, and the comparison between analysis and test results showed good agreement both for the gap between flange just outside ring gasket and the flange bolt force.

The Energy Approach of Elastic-Plastic Fracture Mechanics Applied to the Analysis of the Warm Pre-Stress Effect

2003 ◽  
Author(s):  
Yves Wadier ◽  
M. Bonnamy
Keyword(s):  
Release Rate ◽  
Energy Method ◽  
Ferritic Steel ◽  
Structural Integrity ◽  
Energy Approach ◽  
Experimental Results ◽  
Experimental Program ◽  
Stress Effect ◽  
Integrity Assessment ◽  
Good Agreement

An experimental program was recently carried out in the context of a MPA-EDF collaboration, in order to study the “Warm Pre-Stress” effect on CT25 side-grooved specimens made of 18MND5 (equivalent to A508) ferritic steel. At EDF, an energy approach has been developed and an energy release rate, called Gp, has been defined. Conversely to the J-approach, this energy approach is, in principle, valid in all situations, and can be used in particular to study the “Warm Pre-Stress” effect in RPV structural integrity assessment. For the WPS cycle called “LCF” (Loading + Cooling + Fracture), the comparison to the experimental results and to the results obtained with the Beremin model is very satisfactory, all the results being in a good agreement. For the WPS cycle called “LUCF” (Loading + Unloading + Cooling + Fracture) the results obtained with the energy method, compared to experimental results, show a conservatism which is not very important, anyway smaller than the conservatism obtained with the Beremin model.

scholarly journals Recent Developments of the Linear Matching Method Framework for Structural Integrity Assessment

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Daniele Barbera ◽  
Haofeng Chen ◽  
Yinghua Liu ◽  
Fuzhen Xuan
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Structural Integrity ◽  
Direct Methods ◽  
Matching Method ◽  
Integrity Assessment ◽  
Wide Range ◽  
The Impact ◽  
Linear Matching Method

The linear matching method (LMM) subroutines and plug-in tools for structural integrity assessment are now in extensive use in industries for the design and routine assessment of power plant components. This paper presents a detailed review and case study of the current state-of-the art LMM direct methods applied to the structural integrity assessment. The focus is on the development and use of the linear matching method framework (LMMF) on a wide range of crucial aspects for the power industry. The LMMF is reviewed to show a wide range of capabilities of the direct methods under this framework, and the basic theory background is also presented. Different structural integrity aspects are covered including the calculation of shakedown, ratchet, and creep rupture limits. Furthermore, the crack initiation assessments of an un-cracked body by the LMM are shown for cases both with and without the presence of a creep dwell during the cyclic loading history. Finally, an overview of the in house developed LMM plug-in is given, presenting the intuitive graphical user interface (GUI) developed. The efficiency and robustness of these direct methods in calculating the aforementioned quantities are confirmed through a numerical case study, which is a semicircular notched (Bridgman notch) bar. A two-dimensional axisymmetric finite element model is adopted, and the notched bar is subjected to both cyclic and constant axial mechanical loads. For the crack initiation assessment, different cyclic loading conditions are evaluated to demonstrate the impact of the different load types on the structural response. The impact of creep dwell is also investigated to show how this parameter is capable of causing in some cases a dangerous phenomenon known as creep ratcheting. All the results in the case study demonstrate the level of simplicity of the LMMs but at the same time accuracy, efficiency, and robustness over the more complicated and inefficient incremental finite element analyses.

scholarly journals Effect of Dam Height on The Stability of Earth Dam (Case Study: Karolinka Dam)

2020 ◽  
Vol 26 (3) ◽  
pp. 117-126
Author(s):  
Somia Bredy ◽  
Jan Jandora
Keyword(s):  
Earth Dam ◽  
Before And After ◽  
Factor Evaluation ◽  
Diaphragm Walls ◽  
The Stability ◽  
Earth Fill ◽  
The Town ◽  
Improve State ◽  
Good Agreement

The Karolinka earth-fill dam was constructed between 1977 and 1984 on the Stanovnice river above the town of Karolinka in the region of Vsetínsko in Czech Republic. Because of leakage on the downstream dam face due to technological indiscipline when filling dam layers during the dam construction stage, there were some steps to improve state dam safety. The final rehabilitation is to construct the diaphragm walls from self-hardening cement-bentonite suspension along the length of the dam. In addition to connecting the gallery and abutment (2 × 25 m long) by using jet piles. The article presents numerical modeling of safety factor evaluation associated with the state of the dam body and foundation; before, and after sealing. Also, studying the effect of dam height on its stability by using finite element method is performed by the Plaxis 3D program in the case study of Karolinka dam. It is concluded that measured data shows good agreement with the computed result.

Structural Integrity Assessment of Aging Fixed Steel Offshore Jacket Platforms: A Persian Gulf Case Study

2013 ◽  
Author(s):  
Hamid Golpour ◽  
Mostafa Zeinoddini ◽  
Hadi Khalili ◽  
Ali Golbaz ◽  
Yashar Yaghubi ◽  
...  
Keyword(s):  
Persian Gulf ◽  
Structural Model ◽  
Structural Integrity ◽  
Global Analysis ◽  
Life Extension ◽  
Offshore Platforms ◽  
Perspective View ◽  
Integrity Assessment ◽  
Fit For Purpose

The existing knowledge on the structural integrity assessment of offshore platforms may benefit from case studies on the life extension evaluations of aging structures. This paper presents a case study for the structural integrity assessment of an existing 8 legged aging drilling platform located in the Persian Gulf. The platform is now 42 years old and the objective of the study is to check its fit for purpose for a life extension of 25 years beyond 2012. The structural model is based on the best estimates of the existing conditions of the platform. A number of analysis approach such as i) assessment based on the previous exposures, ii) linear (elastic), iii) equivalent linear (or the linear global analysis with local overload considerations), and iv) non-linear analysis methods have been used to estimate the structural integrity of the platform. The paper provides further background, clarifications and proposed updates to API-RP 2A-Section 17. The paper is divided into three parts. Section 1 is a discussion on the background of the previous assessment study and perspective view on why the case study platform needs to be assessed. Section 2 and Section 3 include the finding of the code-noncompliance points of the platform based on the recommendations of API RP 2A-2007. Section 4 presents the remedy actions recommended for the fit for purpose of the platform.

Review and Case Study of the Linear Matching Method Framework for Structure Integrity Assessment

2016 ◽  
Author(s):  
Daniele Barbera ◽  
Haofeng Chen ◽  
Yinghua Liu
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Crack Initiation ◽  
Structural Integrity ◽  
Direct Methods ◽  
Matching Method ◽  
Integrity Assessment ◽  
Wide Range ◽  
Linear Matching Method

The Linear Matching Method Framework (LMMF) consists of a number of simplified direct methods for generating approximate inelastic solutions and answering specific design related issues in pressure vessel design codes using standard finite element codes. Currently, all the LMM procedures have been implemented in ABAQUS through user subroutines with powerful user-friendly plug-in tools. The LMM ABAQUS user subroutines and plug-in tools for structural integrity assessment are now in extensive use in industries for the design and routine assessment of power plant components. This paper presents a detailed review and case study of the current state-of-the art LMM direct methods applied to the structural integrity assessment. The focus is on the development and use of the LMMF on a wide range of crucial aspects for the power industry. The LMMF is reviewed to show a wide range of capabilities of the direct methods under this framework, and the basic theory background is also presented. Different structural integrity aspects are covered including the calculation of shakedown, ratchet and creep rupture limits. Furthermore, the crack initiation assessments of an un-cracked body by the LMM are shown for cases both with and without the presence of a creep dwell during the cyclic loading history. Finally an overview of the in house developed LMM plug-in is given. Its implementation in ABAQUS finite element solver through an intuitive Graphical User Interface is presented. The efficiency and robustness of these direct methods in calculating the aforementioned quantities are confirmed through a numerical case study, which is a semi-circular notched (Bridgman notch) bar. A 2D axisymmetric finite element model is adopted, and the notched bar is subjected to both cyclic and constant axial mechanical loads. For the crack initiation assessment, different cyclic loading conditions are evaluated to demonstrate the impact of the different load types on the structural response. The creep dwell impact is also investigated to show how this parameter is capable of causing in some cases a dangerous phenomenon known as creep ratcheting. All the results in the case study demonstrate the level of simplicity of the LMMs but at the same time accuracy, efficiency and robustness over the more complicated and inefficient incremental finite element analyses.

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