CALCULATION OF FOUNDATIONS WITH CIRCULAR (CLOSED) IN-PLANE SHAPES

Abstract

It has been found that four reinforced concrete flue stacks being constructed in late 80-ies and early in 90-ies of the 20^th century and being operated at various thermal power stations show practically no settlement, and this fact is not taken into account by any applicable regulatory documents. Foundations of these stacks were designed at the same time and they have been protected by patents of Russian Federation and Republic of Belarus. They represent circular bases made of reinforced concrete piles buried tightly together and forming so-called “slurry wall” with common monolithic reinforced concrete grillage. The grillage presents a direct extension of the stack shaft. One of these stacks has been built in Russia, and three – in Belarus. Due to significant differences in soil conditions and loads in each case, it is a fair assumption to say about regularity of the observed phenomenon. Notwithstanding the fact that circular foundations significantly decrease steel and concrete consumption, construction period and labour input, they have not yet received adequate attention from the side of scientific community and designers. While considering specific examples of the constructed stacks the paper reveals an opportunity to apply calculations which efficiently use passive soil resistance. The presented calculations and designs of the existing foundations make it possible to assess probability of the proposed methodology for the foundations which are analogous in design and which have closed in-plane structure not only for industrial buildings and structures.