scholarly journals Pipe–soil interaction analysis of jointed water mains

1996 ◽  
Vol 33 (3) ◽  
pp. 393-404 ◽  
Author(s):  
B Rajani ◽  
C Zhan ◽  
S Kuraoka
Keyword(s):  
Ductile Iron ◽  
Interaction Analysis ◽  
Water Pressure ◽  
Urban Infrastructure ◽  
Developed Countries ◽  
Temperature Influence ◽  
Average Life ◽  
Winkler Model ◽  
Water Mains ◽  
Water Main

Water mains are important lifelines of modern urban infrastructure. However, in most developed countries, the average life of these cast or ductile iron pipes approaches 50–75 years. In recent years, the disruption of water sevices as a consequence of water main breaks is on the rise in most Cadadian cities. This paper describes the developement of a simplified Winkler model to stimulate the responses of a jointed water main subjected to differential temperature change and water pressure. The simplified Winkler model accounts for axial and radial restraints offered by the surronding soil. In spite of its simplicity, the Winkler model is able to predict the overall response of strains and stresses, which confirms satisfactorily some of heuristic and documented observations on water main breaks. Key words: water main breaks, pipe–soil interaction, temperature influence, Winkler model.

Statistical approach for describing failures and lifetimes of water mains

1998 ◽  
Vol 38 (6) ◽  
pp. 209-217 ◽  
Author(s):  
Jianhua Lei ◽  
Sveinung Sægrov
Keyword(s):  
Data Base ◽  
Ductile Iron ◽  
Counting Process ◽  
Statistical Approach ◽  
Process Models ◽  
Average Lifetime ◽  
Maintenance Practice ◽  
Water Mains ◽  
Near Future

This paper demonstrates the statistical approach for describing failures and lifetimes of water mains. The statistical approach is based on pipe inventory data and the maintenance data registered in the data base. The approach consists of data pre-processing and statistical analysis. Two classes of statistical models are applied, namely counting process models and lifetime models. With lifetime models, one can estimate the probability which a pipe will fail within a time horizon. With counting process models one can see the deteriorating (or improving) trend in time of a group of “identical” pipes and their rates of occurrence of failure (ROCOF). The case study with the data base from Trondheim municipality (Norway) demonstrates the applicability of the statistical approach and leads to the following results: 1). In the past 20 years, Trondheim municipality has experienced approximately 250 to 300 failures per year. However, the number of failures per year will significantly increase in the near future unless better maintenance practice is implemented now. 2). Unprotected ductile iron pipes have a higher probability of failures than other materials. The average lifetime of unprotected ductile iron pipes is approximately 30 to 40 years shorter than the lifetime of a cast iron pipe. 3). Pipes installed 1963 and 1975 are most likely to fail in the future; 4) The age of a pipe does not play a significant role for the remaining lifetime of the pipe; 5). After 2 to 3 failures, a pipe enters a fast-failure stage (i.e., frequent multiple between failures).

An Overview of Private-Sector Financing of Urban Infrastructure Services: A Developing Countries Perspective

1996 ◽  
Vol 1 (1) ◽  
pp. 76-87
Author(s):  
David E. Dowall
Keyword(s):  
Private Sector ◽  
Local Governments ◽  
Urban Infrastructure ◽  
Developed Countries ◽  
Public Provision ◽  
Rapid Urbanization ◽  
Land Privatization ◽  
Special Assessment ◽  
Financing Infrastructure ◽  
Infrastructure Services

Although most private-sector financing activity takes place in developed countries, attention is quickly shifting to less developed countries, where enormous infrastructure deficiencies, rapid urbanization, and limited public-sector resources are forcing governments to consider alternatives to the traditional public provision of infrastructure services. This article provides an overview of the principal methods used by central and local governments to foster the private provision and financing of urban infrastructure services. The techniques include land privatization; development exactions; special assessment and benefit assessment districts; certificates of participation; private contracting of services; leases and concessions; build, operate, and transfer (BOT) projects; public-private partnerships; the privatization of services; commercial bank financing; infrastructure funds; and private bond financing. Each section describes the technique, provides examples of where it is used, and discusses key implementation issues.

scholarly journals Wearable Intelligent System for the Diagnosis of Cardiac Diseases Working in Real Time and with Low Energy Cost

Proceedings ◽  
2018 ◽  
Vol 2 (19) ◽  
pp. 513
Author(s):  
Olga Valenzuela ◽  
Beatriz Prieto ◽  
Elvira Delgado-Marquez ◽  
Hector Pomares ◽  
Ignacio Rojas
Keyword(s):  
Intelligent System ◽  
Principal Component ◽  
Developed Countries ◽  
Support Vector ◽  
Average Life ◽  
Non Invasive ◽  
Wide Range ◽  
Vector Machines ◽  
Advanced System ◽  
Source Of Information

Heart disease is currently one of the leading causes of death in developed countries. The electrocardiogram is an important source of information for identifying these conditions, therefore, becomes necessary to seek an advanced system of diagnosis based on these signals. In this paper we used samples of electrocardiograms of MIT-related database with ten types of pathologies and a rate corresponding to normal (healthy patient), which are processed and used for extraction from its two branches of a wide range of features. Next, various techniques have been applied to feature selection based on genetic algorithms, principal component analysis and mutual information. To carry out the task of intelligent classification, 3 different scenarios have been considered. These techniques allow us to achieve greater efficiency in the classification methods used, namely support vector machines (SVM) and decision trees (DT) to perform a comparative analysis between them. Finally, during the development of this contribution, the use of very non-invasive devices (2 channel ECG) was analyzed, we could practically classify them as wearable, which would not need interaction by the user, and whose energy consumption is very small to extend the average life of the user been on it.

scholarly journals Untangling the Genetics of Human Longevity—A Challenging Quest

Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 585 ◽  
Author(s):  
Dato ◽  
Soerensen ◽  
Rose
Keyword(s):  
Life Expectancy ◽  
Developed Countries ◽  
Significant Rise ◽  
Human Longevity ◽  
Older Individuals ◽  
Average Life ◽  
Average Life Expectancy

Human average life expectancy in developed countries has increased dramatically in the last century, a phenomenon which is potentially accompanied by a significant rise in multi-morbidity and frailty among older individuals.[...]

Generalized dynamic Winkler model for nonlinear soil–structure interaction analysis

2008 ◽  
Vol 45 (4) ◽  
pp. 560-573 ◽  
Author(s):  
Nii Allotey ◽  
M. Hesham El Naggar
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Soil Structure Interaction ◽  
Winkler Foundation ◽  
Deep Foundations ◽  
Structure Interaction ◽  
Design Engineers ◽  
Winkler Model ◽  
Centrifuge Tests ◽  
Cyclic Degradation

The beam on nonlinear Winkler foundation (BNWF) model is widely used in soil–structure interaction (SSI) analysis owing to its relative simplicity. This paper focuses on the development of a versatile dynamic BNWF model for the analysis of shallow and deep foundations. The model is developed as a stand-alone module to be incorporated in commercial nonlinear structural analysis software. The features of the model discussed are the loading and unloading rules, slack zone development, the modeling of cyclic degradation and radiation damping. The model is shown to be capable of representing various response features observed in SSI experiments. In addition, the predictions of the model for centrifuge tests of piles in weakening and partially weakening soil are shown to be in good agreement with the experimental results. This agreement demonstrates the potential of the model as a useful tool for design engineers involved in seismic design, especially performance-based design.

scholarly journals Water Main Failure Risk Assesment / OCENA RYZYKA AWARII MAGISTRALI WODOCIĄGOWEJ

2012 ◽  
Vol 24 (1) ◽  
pp. 115-124
Author(s):  
Andrzej Studziński ◽  
Katarzyna Pietrucha-Urbanik
Keyword(s):  
Water Demand ◽  
Water Storage ◽  
Negative Consequences ◽  
Storage Tanks ◽  
Water Network ◽  
Pipe Failure ◽  
Water Mains ◽  
Water Main ◽  
Qualitative Risk Analysis ◽  
Made In

Abstract Town of Krosno is supplied with water by 3 intakes: Sieniawa, Iskrzynia and Szczepańcowa. After the treatment water flows in water mains to the water network in Krosno. The aim of his paper is qualitative risk analysis of the water main Sieniawa failures. The consequences of the failure: pressure value in the network and its duration, were described for different conditions of failures: time of failure, water demand and water storage tanks initial filling. For simulations of pipe failure water network model made in Epanet 2 program was used. The model was verified both during operation of water network and during the failure, where field data were used. The results of the simulations are corresponding to observations made during the real failures. Negative consequences appear only after emptying the water storage tanks, it results from two features of the storage tanks: they stabilize pressure in the network and for some time can provide water to the network. The time of emptying the storage tanks varies according to water demand their initial filling, it is at least 3 hours. During this time the are no sign of failure. When the storage tanks are empty reduction of pressure an shortage of water are observed on prevailing area of Krosno.

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