A FUZZY LOGIC BASED SOFTWARE FOR OPTIMUM DESIGN OF SIMPLY SUPPORTED ONE-WAY SLAB

[B]A FUZZY LOGIC BASED SOFTWARE FOR OPTIMUM DESIGN OF SIMPLY SUPPORTED ONE-WAY SLAB[/B]

[B]ABSTRACT[/B]

The present work is devoted to demonstrate the applicability of the Fuzzy Logic (FL) to problem of optimum design of slab. A software is developed in Visual Basic on Windows platform based on fuzzy logic to deal with optimum design of simply supported one-way slab taking into account latest IS code provisions. Pre- and post-processors are developed to facilitate the input and output and are explained briefly with suitable application. The results obtained for depth of slab, percentage steel along with the cost of material are compared with those based on conventional design.

[B]INTRODUCTION[/B]

Many decision-making tasks are too complex to be understood quantitatively, however, humans succeed by using knowledge that is imprecise rather than precise. Fuzzy logic [1] resembles human reasoning in its use of imprecise information to generate decisions. Unlike classical logic, which requires a deep understanding of a system, exact equations, and precise numeric values, fuzzy logic incorporates an alternative way of thinking, which allows modeling complex systems using a higher level of abstraction originating from our knowledge and experience. It allows expressing this knowledge with subjective concepts which are mapped into exact numeric ranges. Since knowledge can be expressed in a more natural way using fuzzy sets, many decision and engineering problems can be greatly simplified.
In conventional designs, the optimization problem is stated in precise mathematical terms. However, in many practical problems, the design data, objective function, and constraints are stated in vague and linguistic terms. It appears that it is more reasonable to have a transition stage from absolute permission to absolute impermission. This implies that the constraint is to be stated in fuzzy terms and fuzzy theories can be used to design systems involving vague and imprecise information.

The capability of fuzzy sets to express gradual transitions from membership to membership and vice versa has wide uses. It provides us not only with a meaningful and powerful representation of measurement of uncertainty, but also with a meaningful representation of vague concepts expressed in natural language. Subsequent to its advent in mid 70s, some tentative ideas regarding application of fuzzy sets in civil engineering emerged and were endorsed by civil engineers very enthusiastically. Since then much research has been carried out in exploring the potential of fuzzy sets for dealing with a variety of problems.

As design of R.C.C. structures involves a large amount of uncertainty and as fuzzy logic is good in dealing with fuzzy data, the main aim of the present work is to explore the possibility of using the concept of fuzzy logic in the design of R.C.C slab. The search for optimum solution is made without violating norms laid by IS Code for limit state method of design[2].

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