A framework for the use of reliability methods in deep urban excavations analysis

2021 ◽  
Vol 18 (1) ◽  
pp. 2-14
Author(s):  
Arefeh Arabaninezhad ◽  
Ali Fakher
Keyword(s):  
Reliability Analysis ◽  
Urban Areas ◽  
Design Stage ◽  
Deformation Analysis ◽  
Deep Excavation ◽  
Random Set ◽  
Excavation Process ◽  
Adjacent Structures ◽  
Reliability Methods ◽  
Random Set Method

Deep excavations in urban areas impose deformation to adjacent structures; hence the reliability of deformation analysis for the real deep excavation projects is very important to be assessed. In this study a framework is presented for the use of reliability methods in deformation analysis of deep urban excavations. The suggested framework is applied for 5 real deep excavation projects implemented during last 10 years. All studied cases were recognized as projects of high importance in urban areas, and were monitored during the excavation process. A non-probabilistic reliability analysis procedure, Random set method, in combination with finite element numerical modeling is applied to obtain the probability of unsatisfactory performance for each case. The reliability analysis results are confirmed by field observations and measurements. Typical results for the probability of analytical deformations exceeding the acceptable values along with the site observations and measured displacements for 5 real deep excavation projects show that the reliability analysis could be a beneficial tool for designer. It is concluded that applying the suggested framework in the design stage of deep excavation projects may lead to design more appropriate systems compared to common deterministic design methods.

The Application of Reliability Methods to Tolerancing

1982 ◽  
Vol 104 (3) ◽  
pp. 612-618 ◽  
Author(s):  
D. B. Parkinson
Keyword(s):  
Reliability Analysis ◽  
Failure Probability ◽  
Digital Computer ◽  
Maximum Degree ◽  
Relative Size ◽  
Design Stage ◽  
Design Specification ◽  
Simulation Techniques ◽  
Reliability Methods ◽  
Different Dimensions

Techniques which have been developed to estimate failure probability in reliability analysis are here applied to problems associated with the tolerancing of the dimensions of manufactured components. In particular, a procedure is described which permits, for the general nonlinear problem, the deduction of an estimate of the frequency with which a set of components will fail to assemble together to the design specification. The method may also be used at the design stage to adjust the relative size of tolerances on different dimensions and to permit the relaxation of tolerances to the maximum degree commensurate with a required level of assurance of correct assembly. The calculations required are relatively simple and do not require the use of simulation techniques on a large digital computer. The application of the method described is illustrated by means of examples.

A Dynamic Analysis Of The Impact Of Air Pollution On The daylight Availability In An Open-plan Office In London

2021 ◽  
pp. 94-103
Author(s):  
Jiangtao Du ◽  
Steve Sharples
Keyword(s):  
Air Pollution ◽  
Urban Areas ◽  
Simulation Analysis ◽  
Design Stage ◽  
Design Strategies ◽  
Early Design Stage ◽  
Pollutant Deposition ◽  
Open Plan ◽  
Building Project ◽  
The Impact

The deposition of air pollutants on glazing can significantly affect the daylight transmittance of building fenestration systems in urban areas. This study presents a simulation analysis of the impact of air pollution and glazing visual transmittance on indoor daylight availability in an open-plan office in London. First, the direct links between glazing visual transmittance and daylighting conditions were developed and assessed. Second, several simple algorithms were established to estimate the loss of daylight availability due to the pollutant deposition at the external surface of vertical glazing. Finally, some conclusions and design strategies to support facade planning at the early design stage of an urban building project were developed.

Application of Reliability Analysis to Re-Qualification and Life Extension of Floating Production Unit Moorings

2016 ◽  
Author(s):  
J. Rosen ◽  
D. Johnstone ◽  
P. Sincock ◽  
A. E. Potts ◽  
D. Hourigan
Keyword(s):  
Reliability Analysis ◽  
Production Unit ◽  
Life Extension ◽  
Surface Model ◽  
Original Design ◽  
Coupled Models ◽  
Wide Range ◽  
Reliability Methods ◽  
Ocean Conditions ◽  
Failure Scenario

Life extension and asset integrity of Floating Production Unit (FPU) moorings are issues of increasing importance for operators due to changing production requirements, the requirement to extend service life, and circumstances where the met-ocean Basis of Design (BOD) has increased significantly over the life of the field. Reliability methods are gaining increasing acceptance as increased computing power allows large numbers of simulations to be undertaken using realistic fully coupled models that are validated against prior experiments. When applied to the re-qualification and life extension of FPU moorings, particularly with regard to re-qualification and life extension of in-place moorings, reliability analysis offers considerable advantages over conventional deterministic return period design. This paper details the application of a reliability approach to re-qualification and life extension of a turret-moored FPU that had design met-ocean conditions increased significantly over the life of the field. It explores key elements of reliability analysis including the probabilistic characterisation of met-ocean conditions, adequate representation of vessel dynamics and mooring loads in a Response Surface Model, and a selection of algorithms to solve for the system probability of failure. Discussion points include the advantages of the explicit identification of the most likely failure scenario versus uncertainty as to whether the worst design case has been identified, and the potential for rapid reassessment of reliability for specific design conditions (such as a degraded mooring system or a system for which degradation is ongoing). The results of this study demonstrate the significant advantages to the industry conferred by adopting reliability methods in the re-certification and life extension of existing FPU moorings. In particular, the study highlights that conventional mooring code deterministic design methods, whilst adequate for original design purposes, lack sufficient fidelity to address the multi-faceted issue of re-assessment of notionally marginal legacy systems. For a degraded existing mooring, an application of these methods can demonstrate that the level of reliability of the system is still acceptable, whereas a conventional approach may produce an over-conservative indication that the mooring is non-compliant. Applicable to a wide range of FPUs requiring re-qualification or life extension, the techniques discussed also provide pointers to more efficient and reliable mooring design for not just existing, but also for new FPUs.

scholarly journals Adopting Numerical Models for Prediction of Ground Movements Induced by Deep Excavation

2020 ◽  
Vol 8 (6) ◽  
pp. 976-989
Keyword(s):  
Numerical Models ◽  
Ground Surface ◽  
Sensitivity Study ◽  
Design Criterion ◽  
Deep Excavation ◽  
Soil Behavior ◽  
Analysis And Design ◽  
Ground Movements ◽  
Codes Of Practice ◽  
Adjacent Structures

Control of ground surface settlement induced by deep excavation is of major concern in order to attain safety of adjacent structures and utilities against excessive or differential settlements. Accurate prediction of ground surface movements is an important design criterion in the analysis and design of excavation supporting systems. Many codes of practice are based on a design criterion that satisfies a factor of safety preventing collapse of the system and its surrounding soil. In this research, finite element modeling is adopted to numerically simulate the performance of deep excavation systems and the associated ground movements. The soil behavior was simulated using two types of models; the Mohr-Coulomb model (MC) and the Hardening Soil Model (HS). Field data from monitoring a real deep excavation case history of a retaining system was considered to check the validity of the proposed numerical modeling. A simpler equivalent section replacing the multi-layered soil profile was verified. Then, a sensitivity study has been conducted to study the influence of major parameters that affect ground movements induced by deep excavation. The results of the parametric study were accomplished to construct design charts and drive empirical equations by implementing a design parameter, called the "Stiffness Ratio (R)”, that represents the supporting system stiffness. From these suggested charts and equations, the percentage of maximum vertical ground movements to wall height can be estimated.

scholarly journals CHANGE DETECTION AND DEFORMATION ANALYSIS BASED ON MOBILE LASER SCANNING DATA OF URBAN AREAS

2020 ◽  
Vol V-2-2020 ◽  
pp. 703-710
Author(s):  
J. Gehrung ◽  
M. Hebel ◽  
M. Arens ◽  
U. Stilla
Keyword(s):  
Change Detection ◽  
Urban Areas ◽  
Laser Scanning ◽  
State Of The Art ◽  
Point Clouds ◽  
Deformation Analysis ◽  
Lidar Data ◽  
Efficient Manner ◽  
Incomplete Observations ◽  
Novel Method

Abstract. Change detection is an important tool for processing multiple epochs of mobile LiDAR data in an efficient manner, since it allows to cope with an otherwise time-consuming operation by focusing on regions of interest. State-of-the-art approaches usually either do not handle the case of incomplete observations or are computationally expensive. We present a novel method based on a combination of point clouds and voxels that is able to handle said case, thereby being computationally less expensive than comparable approaches. Furthermore, our method is able to identify special classes of changes such as partially moved, fully moved and deformed objects in addition to the appeared and disappeared objects recognized by conventional approaches. The performance of our method is evaluated using the publicly available TUM City Campus datasets, showing an overall accuracy of 88 %.

scholarly journals RS-SNP: a random-set method for genome-wide association studies

BMC Genomics ◽  
2011 ◽  
Vol 12 (1) ◽  
Author(s):  
Annarita D'Addabbo ◽  
Orazio Palmieri ◽  
Anna Latiano ◽  
Vito Annese ◽  
Sayan Mukherjee ◽  
...  
Keyword(s):  
Association Studies ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Random Set ◽  
Genome Wide ◽  
Random Set Method
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