Challenges in Geotechnical Reliability Based Design

Hazard

Dam filters : physical behavior, probability of malfunctioning, and design criteria

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.Bibliography: leaves 373-379.by Yusuke Honjo.Ph.D

Spatial-temporal prediction of secondary compression using random field theory

AbstractA methodology is presented for observation-based settlement predictions by considering the spatial correlation structure of soil. The spatial correlation is introduced among the settlement model parameters, and the settlements at various points are spatially correlated through these geotechnical parameters, which naturally describe the phenomenon. The method is based on Bayesian estimations, considering both prior information, including spatial correlation, and observed settlements, to search for the best estimates of the parameters. Within the Bayesian framework, the optimized selection of the auto-correlation distance, by Akaike’s Bayesian Information Criterion (ABIC), and the spatial interpolation of the model parameters, by the kriging method, are also proposed. The application of the proposed approach in secondary compression settlement predictions, based on the linear relationship between settlement and the logarithm of time, is presented in this paper. Several case studies are carried out using both simulated settlement data and actual field observation data. It is concluded that the accuracy of settlement predictions can be improved by taking into account the spatial correlation structure, especially when the spacing of the observation points is shorter than half of the auto-correlation distance, and that the proposed approach produces rational predictions of settlements at any location and at any time with quantified errors

Level III Reliability Based Design employing Numerical Analysis - Application of RBD to FEM -

Risk and Reliability in Geotechnical Engineerin

Application of reliability based design (RBD) to Eurocode 7

Codes and Standard

Level III Reliability Based Design employing Numerical Analysis - Application of RBD to DEM -

Risk and Reliability in Geotechnical Engineerin

Sensitivity analysis of vertically loaded pile reliability

AbstractThe purpose of this paper is to examine the influence of geotechnical uncertainties on the reliability of vertically loaded pile foundations and the use of this information in decision-making support, especially when gathering the information necessary for reliability analyses. Two case studies of single pile foundations were selected, and each uncertainty source was investigated to identify which are the most important and influential in the evaluation of vertical pile resistance under axial loading. Reliability sensitivity analyses were conducted using FORM (the first-order reliability method) and MCS (Monte Carlo simulations). The characterisation of uncertainties is not an easy task in geotechnical engineering. The aim of the analyses described in this paper is to optimise resources and investments in the investigation of the variables in pile reliability. The physical uncertainties of actions, the inherent variability of soil and model error were assessed by experimental in situ standard penetration tests (SPT) or from information available in the literature. For the cases studied, the sensitivity analysis results show that, in spite of the high variability of the soils involved, model error also plays a very important role in geotechnical pile reliability and was considerably more important than soil variability in both case studies. From a comparison of the two reliability methods (FORM and MCS), it was concluded that FORM is applicable in simple cases and as a first approach because it is an approximate method and sometimes does not have the capability to incorporate every detail of the problem, namely a specific probability density function or more specific limit conditions

IDENTIFYING VISITOR PREFERENCES FOR LOCATIONS AND FEATURES IN BOGOR BOTANICAL GARDEN, INDONESIA, USING GPS TRACKING AND GEOTAGGED PHOTOS

Research on visitors’ landscape preferences in a botanical garden is useful for understanding what visitors see while they visit the site. Analyzing visitors’ preference by using GPS tracking data and Visitors’-Employed Photography (VEP) is one of approach that successfully implemented in some studies. GPS loggers and visitors’ photos were used in this study to identify and locate features considered impressive by visitors. This research involved 35 normal visitors of Bogor Botanical Garden (BBG) as respondents, who were asked to capture impressive landscape features while visiting the BBG. Each respondent used their own smartphone or camera to take photographs and recorded their actual positions using a GPS logger.  The data of GPS tracking and geo-tagged photos were exported into ArcGIS. The 20 by 20 meters square cell were joined with points' data to calculate density of tracking points and photos points. A cell was categorized as hotspots if the number of points more than 2.5 times of standard deviation. The results show that respondents were concentrated on several geographic locations within the BBG; the most-photographed features were water, structures, and plants. Interestingly, the most-photographed plants were those arranged for recreational (rather than botanical or educational) purposes, suggesting new considerations for managers of botanical gardens

Glass-phase coordination polymer displaying proton conductivity and guest-accessible porosity

We describe the preparation of the crystalline and glassy state of a coordination polymer displaying proton conduction and guest-accessible porosity. EXAFS and solid-state NMR analyses indicated that pyrophosphate and phosphate ions are the main proton transporters in the glass and that homogeneously distributed 5-chloro-1H-benzimidazole in the glass provide the porosity

Detection of diurnal variation of tomato transcriptome through the molecular timetable method in a sunlight-type plant factory

The timing of measurement during plant growth is important because many genes are expressed periodically and orchestrate physiological events. Their periodicity is generated by environmental fluctuations as external factors and the circadian clock as the internal factor. The circadian clock orchestrates physiological events such as photosynthesis or flowering and it enables enhanced growth and herbivory resistance. These characteristics have possible applications for agriculture. In this study, we demonstrated the diurnal variation of the transcriptome in tomato (Solanum lycopersicum) leaves through molecular timetable method in a sunlight-type plant factory. Molecular timetable methods have been developed to detect periodic genes and estimate individual internal body time from these expression profiles in mammals. We sampled tomato leaves every 2 h for 2 days and acquired time-course transcriptome data by RNA-Seq. Many genes were expressed periodically and these expressions were stable across the 1st and 2nd days of measurement. We selected 143 time-indicating genes whose expression indicated periodically, and estimated internal time in the plant from these expression profiles. The estimated internal time was generally the same as the external environment time; however, there was a difference of more than 1 h between the two for some sampling points. Furthermore, the stress-responsive genes also showed weakly periodic expression, implying that they were usually expressed periodically, regulated by light–dark cycles as an external factor or the circadian clock as the internal factor, and could be particularly expressed when the plant experiences some specific stress under agricultural situations. This study suggests that circadian clock mediate the optimization for fluctuating environments in the field and it has possibilities to enhance resistibility to stress and floral induction by controlling circadian clock through light supplement and temperature control