scholarly journals Structural Diagnosis and Performance Assessment of Existing Masonry Aqueducts with Unknown Geometry

2021 ◽  
Author(s):  
Jiang Hu ◽  
Fuheng Ma
Keyword(s):  
Performance Assessment ◽  
Laser Scanning ◽  
Mechanical Performance ◽  
Structural Safety ◽  
Measurement Information ◽  
Masonry Arch ◽  
Weathering Processes ◽  
Assessment Approach ◽  
And Performance ◽  
Structural Diagnosis

Masonry arch aqueducts, as important hydraulic structures, constitute an meaningful part of old irrigation infrastructures in China. The constituent materials deteriorate over time, caused by weathering processes and the defect development, influences the mechanical performance of these structures. The paper presents a comprehensive approach to evaluate the structural safety of an old masonry aqueduct with uncertain mechanical parameters and unknown geometric dimensions. This approach employed the 3D terrestrial laser scanning (TLS) to measure the geometric dimensions, and the discrete element analysis (DEM) to analyze the current operational behaviour state of the masonry aqueduct. As a case study, the Zhaimen masonry arch aqueduct in the famous Red Flag Canal, operating for more than 50 years, was investigated in this study. Obvious defects, such as the continuous loss and falling of mortar and the arch ring detaching, appeared in this old aqueduct. The TLS measurement information was used to construct a DEM model. Then this numerical model was applied to analyze the current performance of the exiting masonry arch aqueduct. The results show that the upper structure and the supporting structure can still be stable assuming that the mortar with no bond strength. In other words, the deterioration of the mortar, due to natural weathering and Calcium ion dissolution caused by natural environment and leakage, would not have a fatal impact on the structural safety. The proposed structural diagnosis and performance assessment approach can provide a reference to safety evaluation for similar masonry arch aqueducts.

scholarly journals Sensitivity analysis of the influences of mortar aging and loss on the structural performance of masonry arch aqueducts

2021 ◽  
Vol 300 ◽  
pp. 01022
Author(s):  
Jiang Hu ◽  
Fuheng Ma
Keyword(s):  
Structural Integrity ◽  
Significant Proportion ◽  
Deep Understanding ◽  
Sensitivity Analyses ◽  
Structural Safety ◽  
Stone Masonry ◽  
Structural Performance ◽  
Structural Behaviour ◽  
Masonry Arch ◽  
And Performance

As commonly used canal system structures, masonry arch aqueducts constitute a significant proportion of Chinese old irrigation infrastructures. Most of these existing aqueducts are well over 50 years old, the deterioration of their constituent materials over time, as well as the development of other defects, significantly affects the mechanical responses of these structures. A deep understanding on the dominant factors that influence the structural safety behaviour of masonry arch aqueducts is essential for determining maintenance and strengthening strategies. Taken the Zhaimen masonry aqueduct in the famous Red Flag Canal as a case study, sensitivity analyses of the influences of mortar aging and loss on the structural performance were carried out. The aqueduct, with unknown geometric dimensions and uncertain physical and mechanical parameters, has defects such as the arch ring detaching from the upper structure and the continuous loss and falling of mortar. The discrete element method (DEM) was employed to analyse the structural behaviour. The results show that the upper structure and the supporting structure are stable under the no bond strength condition. When the mortar is lost locally, the vault position is the most dangerous, followed by the arch shoulder, and then the arch foot part. The mortar loss, manifested as denseness reduction, greatly affects the aqueduct stability. Conversely, the deterioration of the mechanical properties of the mortar, caused by weathering and Calcium ion dissolution due to ambient environment and aqueduct leakage, has relatively little impact on the structural safety. Supplementary grouting of the mortar between the stone masonry should be timely carried out to maintain the structural integrity to ensure the overall stability of the structure. The proposed approach can provide a reference to structural diagnosis and performance assessment for similar structures.

Energy balance and performance assessment of PV systems installed at a positive-energy building (PEB) solar energy research centre

Solar Energy ◽  
2020 ◽  
Vol 212 ◽  
pp. 258-274
Author(s):  
C. Zomer ◽  
I. Custódio ◽  
S. Goulart ◽  
S. Mantelli ◽  
G. Martins ◽  
...  
Keyword(s):  
Energy Balance ◽  
Solar Energy ◽  
Performance Assessment ◽  
Research Centre ◽  
Positive Energy ◽  
Energy Research ◽  
Pv Systems ◽  
And Performance

Application of the endurance time methodology on seismic analysis and performance assessment of hydraulic arched tunnels

2021 ◽  
Vol 115 ◽  
pp. 104022
Author(s):  
Benbo Sun ◽  
Mingjiang Deng ◽  
Sherong Zhang ◽  
Chao Wang ◽  
Yang Li ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Seismic Analysis ◽  
Endurance Time ◽  
And Performance

scholarly journals A Multiple Criteria Decision Making Method to Weight the Sustainability Criteria of System Selection for Surface Mining

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3066
Author(s):  
Michał Patyk ◽  
Przemysław Bodziony ◽  
Zbigniew Krysa
Keyword(s):  
Decision Making ◽  
Performance Assessment ◽  
Multiple Criteria Decision Making ◽  
Surface Mining ◽  
Open Pit ◽  
Mining Equipment ◽  
Surface Mines ◽  
Mining Conditions ◽  
And Performance ◽  
Selection Of

Selection and assessment of mining equipment used in open pit rock mines relies chiefly on estimates of overall exploitation cost. The rational arrangement of mining equipment and systems comprising loading machines, haul trucks and crushing plants should be preceded by a thorough analysis of technical and economic aspects, such as investment outlays and the costs of further exploitation, which largely determine the costs of mining operations and the deposit value. Additionally, the operational parameters of the mining equipment ought to be considered. In this study, a universal set of evaluation criteria has been developed, and an evaluation method has been applied for the selection of surface mining equipment and the processing system to be operated in specific mining conditions, defined by the user. The objective of this study is to develop and apply the new methodology of multi-criteria selection of open pit rock mining equipment based on multiple criteria decision-making (MCDM) procedures, to enable the optimization of loading, handling and crushing processes. The methodology, underpinned by the principles of MCDM, provides the dedicated ranking procedures, including the ELECTRE III. The applied methodology allows the alternative options (variants) to be ranked accordingly. Ultimately, a more universal methodology is developed, applicable in other surface mines where geological and mining conditions are similar. It may prove particularly useful in selection and performance assessment of mining equipment and process line configurations in mining of low-quality rock deposits. Therefore, we undertook to develop universal criteria and applications for the selection and performance assessment of process machines for surface mines, taking into account environmental aspects as well as deposit quality.

Epidemiological surveillance and performance assessment: the two roles of health indicators during the COVID-19 pandemic

2021 ◽  
Vol 17 (2) ◽  
pp. 186-203
Author(s):  
Nathan Genicot
Keyword(s):  
Public Health ◽  
Performance Assessment ◽  
Health Indicators ◽  
Health Policies ◽  
Epidemiological Surveillance ◽  
Public Health Policies ◽  
History Of ◽  
And Performance ◽  
The One ◽  
Massive Development

AbstractThe COVID-19 pandemic has given rise to the massive development and use of health indicators. Drawing on the history of international public health and of the management of infectious disease, this paper attempts to show that the normative power acquired by metrics during the pandemic can be understood in light of two rationales: epidemiological surveillance and performance assessment. On the one hand, indicators are established to evaluate and rank countries’ responses to the outbreak; on the other, the evolution of indicators has a direct influence on the content of public health policies. Although quantitative data are an absolute necessity for coping with such disasters, it is critical to bear in mind the inherent partiality and precarity of the information provided by health indicators. Given the growing importance of normative quantitative devices during the pandemic, and assuming that their influence is unlikely to decrease in the future, they call for close scrutiny.

Precision Dispensed Die Fillets as Non-Conformal Surfaces for Printed Interconnects: Characterization, Optimization and Mechanical Performance Assessment

2021 ◽  
pp. 1-1
Author(s):  
Ludovico Cestarollo ◽  
Mohammed Alhendi ◽  
Rajesh Sharma Sivasubramony ◽  
Gurvinder Singh Khinda ◽  
Darshana L. Weerawarne ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Mechanical Performance
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