Seismic Analysis of Saturated Sand Deposits with Silt Layers

Liquefaction of saturated sands during earthquakes is known to be the cause of significant earthquake related damages, including loss of bearing capacity, lateral flow and spreading, slope failures. In recent earthquakes including the1999 Marmara Earthquake in Turkey, field observations have indicated that silt inclusions or silt layers in the sandy deposits can have significant effects on development of liquefaction. The objective of this work is to analytically study the behavior of saturated sand deposits with silt layers. For this purpose, a hypothetical soil profile in which silt layers exist has been selected. The selected profile was then modeled and analyzed using the LASS-IV code that has nonlinear effective stress analysis capability. As base motion, rock site recordings of the mentioned earthquakes were utilized. Furthermore, as part of this study, a parametric study has been conducted to further understand the effects of silt layers within sand deposits on the onset of liquefaction. The results of the analyses of various parameters such as depth of silt layer, the relative density of sand layer and maximum base acceleration were tabulated to summarize the effect of silt layers on the onset of liquefaction

Private Finance Initiative (PFI) for Road Projects in UK: Current Practice with a Case Study

The long-term sustainable provision of new and high quality maintained road stock is vitally important, especially in times of economic constraint such as Europe is currently experiencing. The Private Finance Initiative (PFI) is one method of financing such large-scale, capital intensive projects. An important aspect of this form of financing projects is that the risks are borne not only by the sponsors but are shared by different types of investors such as equity holders, debt providers, and quasi-equity investors. Consequently, a comprehensive and heuristic risk management process is essential for the success of the project. The proposition made within this paper is that the PFI mechanism provides a Value-for-Money and effective mechanism to achieve this. The structure of this PFI finance and investment on a particular road project therefore enables all project stakeholders to take a long-term perspective. This long-term perspective is reflected in the mechanism of a case study of UK – Class A trunk roads which are examined in detail. This paper presents a novel solution to a modern dilemma

Seismic Response and Liquefaction of Saturated Sands

207 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.An analytical procedure is developed to study the liquefaction potential and seismic response of saturated sands. Method treats the saturated granular soil system as a two-phase nonlinear medium with constituent materials being the granular solid skeleton and the pore water. An elasto-plastic stress-strain rule is developed to simulate the behavior of soils under cyclic stresses. A two part stress path model is used to define the relationship between effective stresses and the cyclic shear stresses. The first part of the model simulates the behavior of saturated sands prior to initial liquefaction and the second part of the model covers the post-initial liquefaction behavior.The model developed is used to simulate large scale undrained shaking table tests on saturated sands. Reasonable agreement is observed between the experimental and analytical results. Finally, a parametric analysis is made to investigate the effects of the base motion characteristics and properties of the layers.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

An artificial neural networks model for the estimation of formwork labour / Dirbtinių neuroninių tinklų modelis, kurio paskirtis – skaičiuoti klojiniams skirto darbo apimtis

Artificial Neural Networks (ANN) is a problem solving technique imitating the basic working principles of the human brain. The formwork labour cost constitutes an important part within the costs of the reinforced concrete frame buildings. This study suggests a method based on artificial neural networks developed for estimating the required manhours for the formwork activity of such buildings. The introduced method has been verified in the study with reference to the test conducted involving two case studies. In all cases, the model produced results reasonably close to actual field measurements. The model is a simple and quick tool for the estimators and planners to aid them in their work. Santrauka Dirbtiniai neuroniniai tinklai (DNT) – tai problemų sprendimo metodas, imituojantis pagrindinius žmogaus smegenų veiklos principus. Statant gelžbetoninius karkasinius pastatus, nemažą sąnaudų dalį sudaro klojinių ruošimas. Šiame tyrime siūlomas dirbtiniais neuroniniais tinklais pagrįstas metodas, kurio paskirtis – apskaičiuoti, kiek žmogaus darbo valandų reikės ruošti klojinius tokiuose pastatuose. Pristatomas metodas tyrimo metu patikrintas remiantis bandymu, susijusiu su dviem atvejo tyrimais. Visais atvejais modelio pateikti rezultatai buvo gana artimi faktiniams matavimams. Modelis – tai paprastas ir greitai naudojamas įrankis, kuris pravers sąmatininkams ir planuotojams. Reikšminiai žodžiai: dirbtiniai neuroniniai tinklai (DNT), klojinys, darbas, sąnaudos, žmogaus darbo valanda, našuma

Controlling the cost of risk management by utilising a phase portrait methodology

The methodology developed in this study presents an approach to the concurrent evaluation of Risk Management (RM) effectiveness during project execution. The method proposed is an adaptation of an approach developed and advocated by Khlebopros et al. (2007) for the mathematical modelling of complex systems, namely the analysis and effects of natural catastrophes. Hence, the method utilizes a phase portrait approach to identify the Prime Cost (PC) of RM of a project. Furthermore, the method provides an approach for comparing the individual identified risks with this PC, and subsequently highlighting a way of classifying and prioritising risks into a rank order for RM attention. The MERA (Multiple Estimating Risk Analysis) approach was utilized for the quantification of risk impact and ultimately the creation of the phase portrait. Besides being accurate and intuitively understandable, the methodology is relatively simple to implement and provides a rapid visualisation of the overall risk extent of a project.</jats:p

Impact of human development on safety consciousness in construction

###EgeUn###The International Labour Organization (ILO) reports that the risk of fatal occupational injuries in developing countries is almost twice as high as in developed countries, indicating a potential relationship between the fatality rates and the development level. The human development index (HDI), based on life expectancy, knowledge level and purchasing power parity, endorsed by the United Nations Development Programme, is a widely accepted measure of the development level. This study investigates the relationship between the HDI and the fatality rates reported by the ILO. A 23-country data set is used to demonstrate the general trend of the relationship followed by country-specific analyses for Australia, Spain, Hungary and Turkey. The study conducted is limited to fatal occupational injuries in construction, where the accidents are notoriously high. The results demonstrate a statistically significant inverse relationship between the fatality rates and the HDI