Popovych M., Medvedieva S.

Vinnytsia national technical university, Ukraine

Choice of rational design decisions of foundations

The article highlights the issue of solving the first stage of the task: the application of heuristic methods of construction, methods of manual synthesis and rational choice KTRF or the formation of the bank with the implementation of the search options and rational choice KTRF on computers.

Modern scientific-technological revolution, with its fast developing science, the booming technology and manufacturing came into conflict with the old and unproductive method of "trial and error" in developing new solutions and in search the necessary information of the known technical solutions.

Currently in the foundation building there are deficiencies found in a comprehensive, systematic approach concerning the development and search of the optimal design decisions in the foundations (KTRF).

Taking into consideration that the requirements for building structures and products as components of household construction complex are constantly growing, there is need in the development of the system algorithmic support during the decision-making process which allows to consider the number of options of the construction of foundations and processes for their manufacturing and application in building production, to evaluate them on a larger number of criteria and to choose a rational KTRF that complies with international technical level or is higher than the last.

The ultimate goal of research is to develop scientific principles and methods of synthesis and selection of rational KTP to increase bearing capacity, design and operational reliability, reducing material consumption and labor in the manufacturing of foundations based on mathematical models of multi-choice.

The initial data is the technical design of Reference (TOR) for technical system that will be developed and the banks of well-known technical solutions for the elements of foundation designs and their production technology.

In the foundation construction like in no other field of construction required a comprehensive, systematic approach is required to be employed to all design and manufacturing operations performed at zero-cycle.

Based on the identified systematic relationship between design and technology the following sequence of operations of the task is offered:

- Synthesis of admissible technical design decisions;

- Respectively, for each of them - synthesis of all the technological solutions that implement them;

- Formation of the matrix of alternative KTRF;

- Choices for each design decision of the best possible technological variants of Technology;

- Rational choice KTRF of the full system design and technological criteria;

- The choice of rational KTRF.

A number of known methods were put as the basis of present scheme of search and rational choice KTRF. They were developed using heuristic methods of morphological analysis [1, 3], which tried to search optimal KTP of aerospace products, where sufficient for practical application of the convergence of theoretical and experimental results had been found [2].

Search Method KTRF is based on the methods of morphological analysis. It allows us to consider only distinctive features of the improved technical system found in the bank of known technical solutions, or by changing the sequence of operations or scheme of structural elements, to receive the necessary design decisions at an early design stage.

This methodology includes the following main stages:

- Precise formulation of technical design decisions;

- Construction of data banks and technology elements of the design (drawing up a list of all the morphological characteristics of the foundation);

- Synthesis of structural variants taking into consideration technical limitations (for each characteristics of morphological characters synthesis of possible options);

- The allocation of functional acceptable alternatives of the constructions;

- Synthesis of technological solutions;

- Selection of the best combinations of options for features.

The bases of the proposed methods in developing a simple specification are given below.

1. Formulation of TOR. To develop a new rational design of shallow pile foundation.

Restrictions: concrete materials consumption compared with traditional foundations of this type is to be reduce to 2.0 - 2.5 times per 1ts of the external load.

2. Making banks of all morphological characteristics of the foundation, in the structural features of morphological structure.

In the space of design options one can divide three subspaces that meet the basic structural elements of the foundation: α - plate; β - shoe; γ - reinforcement. The schemes of the processes, which realize them, divide the space of technology into three subspaces.

3. The options variants are made on the base of each morphological characteristic:

α₁₁ - rectangular solid plate;

α₁₂ - rectangular ribbed plate;

α₁₃ - hollow plate in the central part;

α₁₄ -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

α_1n - hollow plate in the central part filled with ballast material;

β₁₁ - solid section shoe;

β₁₂ - hollow shoe;

β₁₃ - tube section shoe with the ribs on the outer edge;

β₁₄ -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

β_1n - tube section shoe with the ribs along the inner edge;

γ₁₁ - smooth profile reinforcement;

γ₁₂ - rolled section reinforcement;

γ₁₃ - reinforcement with metal plates with openings;

γ₁₄ -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

γ_1n - plate reinforcement with metal plates, and shoe reinforcement with the spatial frame of rebar rolled section.

If necessary, the number of features of the foundation and the list of options on the signs can be increased.

4. Synthesis of options and features combined with analysis of combinations of complete system design and technical criteria, taking into account the constraints imposed, for example:

α₁₂ - β₁₂ - γ₁₂

α_in - β₁₂ - γ_in and so on.

The analysis of table combinations suggests that the methods of morphological analysis allow to get unexpected combinations of characteristic features that are directly derived from the structure.

If at the stages of drawing up the banks of characteristic signs and symptoms of options you are to apply a universal method that synthesizes such methods of morphological analysis and other heuristic methods, such as associative, the method of focal objects [3] or methods ARVZ [1], the combination of signs of options in this case gives more detailed information for a person who makes decisions, allowing early design KTRF get to the international standards or invention.

For example, applying the method of focal objects based on the transmission of characteristics of randomly selected objects onto the improved foundation, we get unexpected variants of characteristics, including the reinforcement:

a) by analogy with reinforced composite materials used in space technology, we apply a similar fiberglass reinforcement for the improved foundation (γ₂₁);

b) ballast material, for the uniform distribution of tension, is divided in accordance with height into separate layers of technical fabrics (on the principle of splitting the tanker into separate tanks) (γ₂₂) and so on.

Analyzing the possible combinations including restrictions on consumption of reinforced concrete, we get unexpected combinations of options that extend the initial region of combinations of options drawn up only on the basis of morphological analysis techniques:

α_1n - β₁₃ - γ₂₂ and so on.

The given combination of variants describes the necessary foundation designs considering limitations of materials from the point of view of structural positions. Similarly the analyzes of combinations of options is performed including signs of technological parameters.

Comparing the most rational combinations based on the principles of methods of morphological analysis (1 type) and principles of the universal methods, including-besides the methods of morphological analysis of one of the associative methods or methods ARVZ (2 type), we can conclude that the second type of combinations more fully meet technical conditions and criteria constraints.

Conclusions

1. Application of heuristic methods can improve search and rational choice of design and technological solutions of the foundations, to create mathematical models of multi-choice of implementation on a computer.

2. Methods of synthesis KTRF are based on the universal application of heuristic methods, including methods other than morphological analysis, and also one of the associative method or methods ARVZ, effective in solving technical problems, based only on the methods of morphological analysis.

References

[1] Altshullera G. S. Creativity, as precise science. / G. S. Altshullera. -: Soviet Council, 1979. – 176 p.

[2] Orlovskiy S. A. Problems of decision-making of non-definite information. / S. A. Orlovskiy. - Moscow: Nauka, 1981. – 208 p.

[3] Polovinkin A. I. Methods to search for new technical solutions. / A. I. Polovinkin. - Yoshkar-Ola: Maryyskoe knyzhnoe Publishing, 1976. – 192 p.