摘要:

This paper examines the proposition that structural trusses and pipe networks for water supply are closely related in a mathematical sense. It shows that in terms of representation, physical quantities, constitutive equations, analysis problem formulations and methods of analysis they both belong to the same class of nonlinear potentiated networks, the truss being a special linear case for problems of analysis. The analysis of nonlinear potentiated networks may therefore be efficiently performed by linearization of the relevant nonlinear quantities and the iterative use of well-known truss analysis methods. The commonality established between structural trusses and water supply systems has potential for exploitation in respect of other network-related problems of optimum design, reliability evaluation and design for resilience.

ISSN:0263-0257    

DOI:10.1080/02630258408970327

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper critically reviews the bounds developed for the probability of union of events in structural reliability theory and other disciplines. The aim of this study is to show how the bounds developed in other fields can be directly used in structural reliability theory and to highlight the areas in which further research would be beneficial. It should be emphasised that the reliability problem is considered here only as one of probability theory: It is assumed that the probabilities P(Fi) and P(Fi∩Fj) are all properly defined and that methods are available for their evaluation. Some ideas are introduced to improve the linear bounds by the inclusion of higher order intersections. An improved lower bound has been developed using nonlinear combinations of P(Fi∩Fj) in place of P(Fi∩Fj∩Fk). Finally a computer algorithm based on Hunter's idea is presented for the evaluation of the upper bound.

ISSN:0263-0257    

DOI:10.1080/02630258408970328

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This study deals with the imprecision associated with estimating the risk of health effects due to environmental causes. The major thrust revolves around the notion that the calculation of statistical risk, itself a probability, contains significant imprecision because of the cascade of error through the computations on which the risk, or probability of contracting a disease, is based. The cascade or risk is an old problem in mathematics and physics, and the conventional issues involving round-off, truncation and related measurement errors are not discussed here. The potential inadequacy of the model by which risk is calculated, the inherent variability in the stochastic processes by which the disease mechanism or initiator is transported down-gradient, and the variability inherent in varying levels of human sensitivity are of more concern. These all conspire to develop a distribution of risk rather than a scalar value, and policy-makers must deal with this distribution in a rational and consistent way. Some suggestions are offered for managing this problem.

ISSN:0263-0257    

DOI:10.1080/02630258408970329

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The paper describes a computer program for analysis and simulation of large-scale water distribution networks. The simulation facility enables the evaluation of system hydraulic and cost operation over extended time periods. An efficient user interface has been provided which allows interactive operation with graphical displays. The program computations use well established network solution techniques together with a range of specially developed models. With these features, the program has now been accepted as a powerful tool with a number of practical applications throughout the water industry.

ISSN:0263-0257    

DOI:10.1080/02630258408970330

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A deterministic inventory computer model is developed and used in selecting the optimum sizes and number of on site refuse storage systems. The majority of these systems studied are either hauled containers or open waste dumps. The optimum sizes were selected by the computer program by comparing the cost of longer refuse storage times (larger storage containers or areas and lesser frequency of refuse pickup and collection vehicles) versus shorter refuse storage times (smaller storage containers or areas and greater frequency of refuse pick-up and collection vehicles).

ISSN:0263-0257    

DOI:10.1080/02630258408970331

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

It is well recognized that the bottom reinforcement in rectangular slabs subjected to uniformly distributed load may be curtailed near the edges. Such reinforcement arrangements are naturally more economic than those in which the bottom reinforcement is continued to the supports. Most of the minimum reinforcement solutions for rectangular slabs deal with the latter type of reinforcement arrangement. In this paper, minimum reinforcement solutions for rectangular slabs having curtailed bottom reinforcement are presented. The solution is based on the theory of optimal plastic design for piecewise constant reinforcement. Solutions are presented for slabs with all edges fixed, and with two opposite edges fixed and the other two simply supported, for different aspect ratios of the slab. The minimum moment capacity volumes of the slab are found to be about 10–25% less than those of the slabs in which bottom reinforcement is not curtailed.

ISSN:0263-0257    

DOI:10.1080/02630258408970332

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper describes how probabilistic fracture mechanics calculations have been used to assess the notional probability of fracture of a number of crack-like weld defects in an offshore structure. The results were used in a decision making context to establish a rational repair sequence, so that the defects could be repaired on an order-of-merit basis. This was necessary in order to minimize risks because of the possibility of the repair programme being curtailed, for instance, by bad weather. The analysis procedure, which is based on the probabilistic treatment of a standard deterministic fracture model, could be applied in any similar situation where appropriate information is available. An important new aspect is the way in which fracture probabilities are assessed for defects which are large compared with the size of fracture toughness test specimens.

ISSN:0263-0257    

DOI:10.1080/02630258408970333

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630258408970334

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630258408970335

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630258408970338

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor