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The soil parameters for large, complex landslides are typically derived from incomplete information based on a small sample set due to budgetary constraints. This informational incompleteness results in large statistical uncertainty in landslide reliability analyses. In this article, the bootstrap technique is proposed to quantify the statistical uncertainties associated with a small sample set, and a practice-oriented reliability analysis is performed. The results suggest that the obtained reliability indices are characterized by a long tail, in which the worst-case scenario has a local extreme value and a small population. The statistical uncertainties are quantified and characterized by a confidence interval at a specified confidence level. The confidence interval of the reliability index and identification of the worst-case scenario enable engineers to make more informed decisions. [ABSTRACT FROM AUTHOR]

A specific standard for stability analysis of earth and rock-fill dams with a height of more than 200 m is lacking in China. Thus, the safety standard for slopes of these dams is explored on the basis of reliability analysis. The dams with a height over 200 m are divided into special Classes 1 and 2 depending on the risk levels and acceptable risk standards. The concept of reliability theory-based relative ratio of safety margin is utilized to establish the relationship between annual failure probability and safety factor, thereby obtaining the reasonable safety factors for different dams. The reliability indexes and safety factors of dams under various heights and slope ratios are calculated. Results show that the values of safety factors for special Classes 1 and 2 are 1.70 and 1.60 under normal conditions and 1.40 and 1.35 under seismic conditions. The validity of the proposed values of safety factors are verified by carrying out stability analysis for several practical projects in China. These results can provide a reference for exploring the safety standards of dams with a height of more than 200 m. [ABSTRACT FROM AUTHOR]

Zhang, H.Z., 2020. Evaluation of foundation stability of port geotechnical engineering projects based on random field theory. In: Al-Tarawneh, O. and Megahed, A. (eds.), Recent Developments of Port, Marine, and Ocean Engineering. Journal of Coastal Research, Special Issue No. 110, pp. 120–124. Coconut Creek (Florida), ISSN 0749-0208. With the rapid development of marine trade and maritime transportation industry, the increase of port-based enterprises has promoted the construction and expansion of port projects in China. Since the spatial correlation of the soil mass in ports is quite complex, the traditional foundation stability evaluation methods have great uncertainty. The random field theory considers the autocorrelation coefficient of the soil mass, so this paper applies the reduction function to calculate the stability of the foundation of geotechnical engineering projects in actual ports based on the random field theory, and explores the feasibility of the random field theory in the calculation of foundation stability. The research results show that: taking the portside geotechnical engineering project in the Pearl River Delta as an example, by applying the random field theory and the reduction function to examine the reliability of the ten tests, it can be clearly seen that the reliability index of the foundation stability of the geotechnical engineering project calculated by the reduction function increases significantly. After applying the random field theory, the calculated foundation stability of the actual port geotechnical engineering project is more reliable. The research in this paper provides a theoretical basis for applying random field theory in the reliability calculation of port foundation engineering projects. [ABSTRACT FROM AUTHOR]

Based on the clinical application data of medical X-ray computed tomography (CT) in the Shanghai Sixth People's Hospital, this study transformed it into the product reliability index requirements, and took the mechanical representative component-examination table (hereinafter referred to as "patient table") and the electronic representative component-DCB (data control board) as examples. Based on the relationship between failure characteristics and clinical application data, a complete set of closed-loop implementation methods from reliability index requirements to reliability design and verification are discussed.

• Use of binary bits of integers to allocate the sign array in the Rosenbueth method (PEM). • Application of PEM in slope stability analysis by confirming normal or lognormal distribution of the factors of safety. • Successful application of PEM in a 165 m high rockfill dam. Calculating the reliability index is a common approach used in structural reliability analysis. It typically involves a procedure for determining the reliability index of a performance function. The method developed by Rosenblueth only requires calculating the objective functions at selected weighting points. The method is easily implemented and free of numerical iteration. However, it requires large storage space for sign information during coding. In the present study, the problem of large storage space is easily solved by taking the binary bits of integers, which can be achieved with most commercial compilers. By conducting an extensive numerical investigation based of the chi-squared goodness test, it is found that the factors of safety obtained in slope stability analysis follow normal distributions if the uncertainty variables are normally distributed. Meanwhile, the factors of safety obtained in retaining-wall stability analysis follow lognormal distributions. Therefore, the conventional slope stability analysis methods are confirmed not substantially change the distribution form of the performance function, which is a condition that makes the Rosenblueth method applicable. In conjunction with other reliability analysis methods (Monte Carlo and FORM), the Rosenblueth method is shown to be useful for the reliability analysis of slopes and retaining walls with satisfactory accuracy. This study applies the proposed method to the analysis of the 165-m-high earth core rockfill Xiaolangdi Dam in China. [ABSTRACT FROM AUTHOR]

Membrane structures deteriorate with time. This results in reduction of their resistance, and consequently, of their reliability. Material aging is one of the main causes of structure deterioration. This paper investigates statistical characteristics of naturally aged polyvinylidene fluoride PVDF-coated fabrics' mechanical properties and calculates reliability indexes on the basis of Central Point Method and Rackwitz-Fiessler Method. Five groups of experimental fabrics were taken from different existing engineering structures or indoor warehouse in China, which have been naturally aged for more than 10 years. First, series of tearing tests, uniaxial and biaxial tensile tests were carried out to study the mechanical properties. Then, the uncertainties of material properties, material's dimension, computational model and load effects were discussed and the reliability indexes were studied by two methods according to the ultimate limit state. Finally, reliability indexes of aged PVDF-coated fabrics were compared with that of unaged coated fabrics. Results show that the impact of natural ageing on the properties of PVDF-coated fabric can not be ignored in reliability analysis and membrane structures design. These data offer a further understanding of aged PVDF-coated fabrics' mechanical properties and provide references for the durability analysis of tensioned membrane structures. • Five groups of naturally aged PVDF-coated fabris were taken from engineering structures or indoor warehouse in China. • Series of tests were carried out to study their mechanical properties. • Uncertainties of material properties, material's dimension, computational model and load effects were studied. • Reliability indexes were calculated by two methods. • Reliability indexes of aged coated fabrics were compared with those of unaged fabrics. [ABSTRACT FROM AUTHOR]