摘要:

Fuzzy set theory is used to produce risk factor values for a building code. Working through reliability indices, a transformation is developed to convert estimates of relative social importance of a building into code load factors. The importance estimates are found by surveying knowledgeable members of society or playing their roles, and by using fuzzy set theory to combine their views according to their significance. An extension, again using fuzzy set theory, brings in the use of multiple criteria on which to base judgements. An example gives risk factors close to those in an existing code.

ISSN:0263-0257    

DOI:10.1080/02630258408970340

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper shows how numerical values of utility can be estimated from incomplete information, by treating the unknown utilities as random variables. Preferences between the possible decision outcomes, together with the decision-maker's response to various simple hypothetical lotteries involving these outcomes, are - used to define a region oifeasibilityJorthe utilityiunction.This is combined.within Bayes' theorem with a prior probability density function for the unknown utilities. The prior probability is specified through an invariance argument using the uniqueness of utility only up to a positive linear transformation. The invariance argument stems from a maximum entropy principle and the invariance that must obtain under allowable transformations.

ISSN:0263-0257    

DOI:10.1080/02630258408970341

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A short account is presented of Australian dams which have failed to perform according to expectation. The coverage is more extensive than that adopted by ICOLD, and extends to all dams with a maximum wall height of 7 m or more. The failure rate is found to be independent of height; and the number of failures to have approximately doubled every 25 years between 1857 and 1983. The major reasons for these failures, and their implications for current practice, are discussed.

ISSN:0263-0257    

DOI:10.1080/02630258408970342

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper discusses a common network flow problem that arises in four areas of civil engineering. The problem is one of identifying arc flows that simultaneously satisfy the circuit and node law constraints for a given network. Applications and computational procedures in the areas of elastic structural analysis, hydraulic network analysis, traffic equilibrium and construction task scheduling are described. The interpretation of decision variables and mathematical functions will vary depending on the application, but the general priblem formulation and solution technique for each application remains essentially unchanged. Analogies between the different applications may enhance the conceptual understanding and intuition of engineers working in each area.

ISSN:0263-0257    

DOI:10.1080/02630258408970343

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Mathematical programming methods are among the most powerful optimization techniques. They may be classified into direct or indirect methods. In the indirect methods, the constrained design problem is converted into a sequence of unconstrained problems using penalty functions. In this way, the optimal solution of a constrained problem may be obtained using one of the unconstrained search techniques. The interior penalty function appears to be the most reliable uncon strained method while the variable metric method seems to be an extremely powerful algorithm. This paper presents the use of the interior penalty function coupled with the variable metric method for the solution of structural design optimization problems.

ISSN:0263-0257    

DOI:10.1080/02630258408970344

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper examines the meaning of the term effective length. The failings of the relevant literature to satisfy the needs of present and future automated design techniques are highlighted.

ISSN:0263-0257    

DOI:10.1080/02630258408970345

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

To reduce the effect of lateral earthquake ground motion on structures, active control systems can be used. To-date, almost all the investigators have assumed that control forces are available immediately with precise magnitude as required. Using simulated earthquakes, it is shown that the failure probability is generally reduced by using a perfect control system. A time lag always exists, however, between the instant when a control force is needed and the instant when the required control force is actually generated. The time required to generate the desirable magnitude of the control force is termed the time-constant. The effect of these time factors on the reliability of structural control is investigated and illustrated with numerical examples.

ISSN:0263-0257    

DOI:10.1080/02630258408970346

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630258408970347

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630258408970348

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor