Keywords: optimisation, interval analysis, concrete and reinforced concrete single base, verified numerical computing, automatic design.

The most common foundation method for industrial halls and buildings is using concrete and reinforced concrete single bases. For the technical details of these bases see the applying standards in references [3,4]. This design is not a uniquely determined task. Most factors are variable within certain limits, such as the shape of the footing and the foundation level. Finding the most economical one from the technically equivalent solutions takes lengthy calculations [5]. To find the optimal single base we used the interval arithmetic of [2] and some modifications of the subroutines for solving constrained global optimisation problems of [1].

Several types of load combinations were tried and there were remarkable differences between each run. In order to examine the relationship between run times and initial data more experiments were proposed. The run time of each calculation was taken into consideration as well. Two kinds of calculation series were made concerning to footings with and without reinforcement, respectively.

The conclusion is that reinforced foundation body requires less concrete than the one without reinforcement. On the other hand the individual foundation body's entire cost should be studied to decide when and in what situations reinforcement should be used. Optimising the budget does not simply mean differences in volumes but it is the reinforcement, its erection, the formwork, and such other work that specifies the budget. This cost in Hungary balances out with duplicating the required concrete. Up to around 1.0 m eccentricity foundation bodies without reinforcement are cheaper whilst above this value the more economical one is the reinforced footing. In countries where manpower is more costly compared to the cost of raw materials, this ratio shifts to higher eccentricity.

1

R. Hammer, M. Hocks, U. Kulisch, and D. Ratz, Numerical Toolbox for Verified Computing I., Springer-Verlag, Berlin, 1993.

2

O. Knüppel, PROFIL/BIAS V. 2.0, Bericht 99.1., Technische Universität Hamburg-Harburg, 1999.

3

MSZ 15004-1989 Síkalapok határteherbírásának és süllyedésének meghatározása (in Hungarian) (Title in English: MSZ 15004-1989 Determination of limit load bearing capacity and settlement of shallow foundations).

4

MSZ 15002/1-87 Építmények alapozásának erotani tervezése. Általános méretezési eloírások. (in Hungarian) (Title in English: MSZ 15002/1-87 Mechanic design of the foundation of buildings. General sizing requirements.)

5

L. Rózsa, Alapozás kézikönyve (in Hungarian) (Title in English: Handbook of Foundations), Budapest, 1969.

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