Deformations of bases of annular foundations

Conclusions 1. The deformation zone depth and the settlements in annular foundations are smaller than in circular foundations for equal underside areas, other conditions being equal.2. For equal settlements, the load transmitted to an annular foundation may be higher by 30–40% than the corresponding load transmitted to a solid foundation.Odessa Civil-Engineering Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 22–23, July–August, 1985.     

Interaction between shallow foundations and slightly heaving bed soil

Conclusions 1. When foundations ascend as a result of frost heaving, normal heaving forces are reduced. Measures directed not toward overcoming heaving forces, but toward reducing the deformations caused by these forces to limiting allowable values could therefore be considered in designing shallow foundations.2. The pressure transmitted to the soil exerts a greater influence on foundation heaving than does the lower-surface area of the foundation.3. The optimum shape of the lower surface of a columnar foundation on heaving soils is square.4. The cost of 1 m² of the overall area of a building is reduced by 10 rubles on average due to use of shallow foundations.General Scientific-Research Institute of Experimental Planning. Scientific-Research Institute of Bases and Underground Structures. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 21–23, July–August 1984.     

Stresses in a bed beneath rigid and flexible foundations under initial and repeated loadings

Conclusion The experiments indicated that repeated loading of flexible foundations (in contrast to rigid foundations) may result in significant variation in the stresses beneath them, which will lead to an appreciable increase in bending moments, elongations in reinforcement, and even to failure of the flexible foundation under a loading that did not give rise to dangerous deformations during the initial loading.Scientific-Research Institute of Bases and Underground Structures. Giproniiaviaprom. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 29–31, January–February, 1987.     

Multifunctional combined foundations on permafrost soils

The writers examine the construction of multifunctional combined foundations on permafrost soils, as approved for strengthening the foundation system of an administrative-industrial building in Norilsk. Such foundations make it possible to control the building deformations developed as a result of increase in the pile loads or in the settlements of the piles due to decrease in their bearing capacity when the soil base temperature increases.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 26–28, September–October, 1992.     

Experimental confirmation of a criteriong for the bearing capacity of a bed

Conclusions 1. Experiments with full-scale foundations confirm that even after the start of ground bulging, foundation settlements may even continue to stabilize, the average settlements cease to be allowable, and the s-p curve is even simplified, approaching a linear curve, when the pressure beneath the foundation is increased. At the start of bulging, however, settlement nonuniformities of the foundations increase sharply and even become inadmissible.2. The limiting pressures initiating ground bulge correspond to that section of the s-p curve, where its initial segment converts into an inclined section that is close to a straight line. Up to pressures equal to half the limiting pressures and for shallow rigid foundations on sands of average density and dense sands, the s-p curve is close to linear, and the foundation settlements can be calculated in conformity with the recommendations of the Construction Rules and Regulations.3. For foundations on loose sands, the compaction of sand during shear, which may lead to inadmissible settlement nonuniformities even at minimal pressures due to the foundations, are the most dangerous settlements. The possibility of these nonuniformities should either be eliminated by compaction prior to construction, accounted for during design, In predicting settlement nonuniformity, we should proceed from data on plate tests of loose sands with consideration of the recommendations in [5, 6].VNIIOSP. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 23–26, March–April, 1988.     

Investigation of the operation of pile foundations with dynamic loads

Static and dynamic tests of two single piles and a cluster of four piles with a high foundation mat were conducted in full-scale conditions. A procedure is suggested for processing tests to evaluate the seismic stability of pile foundations, and coefficients are derived for reduction of the load on piles, which fully agree with analogous seismic coefficients of the conditions of operation given in Construction Standard and Rules and make it possible to choose the optimum variant of a pile foundation.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 26–27, November–December, 1992.     

Foundations in punched trenches at construction projects in chuvashin

Results are presented for tests on 27 foundations in punched (tamped-out) trenches (including some tested under repeated loading and when a long period had elapsed after their construction), which showed high technical-economic indices. Experience with their operation permits recommending wider use of this foundation construction method.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 18–21, March–April, 1992.     

Settling of large buildings and structures erected on clay loess grounds

Conclusions 1. Some 60% of foundation settling in clay grounds of the type considerered here takes place during the construction period. The settling continues for 10 years, and then for an additional 20–25 yr at a very low rate.2. The II-B.5–67 scheme of pile foundation, proposed by the SNiP from the analysis of deformations, is substantiated by the actual settlings.3. Settlings calculated by different methods differ but little among themselves and are in fair agreement with the actual settlings. The single instance of great discrepancy between the theoretical and actual data evidently is due to changes in ground facies and the rate of compactions.4. The published data [1, 2] on a marked discrepancy between the theoretical and actual data on settleling for the large structures should be regarded as anomalies associated with foundations in sandy grounds and acted upon either only by the static loads (minor settlings) or by the combined static and dynamic ones (large subsidences).5. Observations of settling should start with the construction, at loads not exceeding the operational, with accurate records kept on loads transmitted to the foundation.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 29–31, September–October, 1971.     

A method of predicting the vibration level of structures and soil from test results

Conclusions 1. The promising nature of the proposed method of predicting the vibration levels in structures and the ground, which is based on experimental data on the harmonic oscillations of a small footing, is demonstrated.2. One of the essential stages of the method is to determine curves of the dynamic contact stresses acting over the lower surface of the foundation under design. It is established that the latter are in different phases with respect to one another and lead the displacement of the foundation, and also that at no time do the dynamic contact stresses equal zero over the entire lower surface of the foundation.3. The method makes it possible to compute the elastic and damping characteristics of the beds of foundations, which differ in shape and area of the lower surface, to determine the vibration level of structures interacting with the ground, and to determine the level of ground vibrations beyond the structure both on the surface, and within the ground, as well as in surrounding structures. Experiments with a small-foundation footing are much cheaper than experiments with certain foundations that are similar in any respect to a prototype foundation, particularly where the latter has large dimensions.4. It is necessary to conduct studies in the proposed direction mainly to accumulate experimental data.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 18–21, July–August, 1977.     

Evaluation of the damping factor of foundation bases subjected to vertical vibrations

Conclusions 1. The damping factor b depends on the elastic properties of the soil base and the dimensions of the lower surface of the foundation. Hence, one of the values — the coefficient of uniform elastic compression C_z — makes it possible to find both the elastic and damping characteristics of the soil base. To evaluate the damping characteristics, it is expedient to use the specific damping factor introduced in this article.2. To find the maximum amplitudes of unsteady vibrations of massive foundations under the action of an instantaneous impulse, use can be made of Eqs. (21)–(23), which determine the factor b_z if the limit from which the elastic waves may be reflected (rock, soil layer with higher wave velocities, etc.) is located below the lower surface of the foundation at a depth greater thanl/2,l being calculated from Eq. (16). To find the parameters of steady vibrations of massive foundations, the damping properties of the soil base are determined by the factor b_z, calculated from Eqs. (12)–(15).3. The equations for the factor b_z are related to the mean soil conditions; however, the effect of the characteristics of the geologic morphology is exerted on this factor more strongly than on the rigidity modulus of the soil base; hence, it is desirable to gather experimental data for the systematization and processing of which use can be made of the relations obtained in this article.Scientific-Research Institute of Bases and Underground Structures. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 15–18, September–October, 1981.     

Results of long-term investigations of bed and foundation deformations of buildings within the historic moscow kremlin

Long-term detailed investigations of bed and foundation deformations of structures within the Moscow Kremlin are codified; causes of the deformations are studied with respect to all of the most complex components, and technical measures taken to strengthen the beds and foundations of the historic buildings are substantiated to ensure their longevity and preservation.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 15–18, November–December, 2004.     

Interaction of shallow strip foundations and heaving soils

Conclusions 1. The strip foundation rise caused by normal heave forces is linearly proportional to the pressure on the soil base, for all practical purposes.2. The pressure transmitted to the soil base affects the heave deformation over the entire freezing soil thickness.3. For identical loads on the foundations, the larger the underside width, the greater the foundation rise.4. The unit normal heave forces decrease as the underside width increases, and increase (nonproportionally) as the soil freezing depth increases.TsNIIÉPsel'stroi. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 5–7, July–August, 1987.     

Experimental studies of slotted foundations for the supports of high-voltage lines

Conclusions The results of the tests that we conducted on full-scale prismatic foundations and their model with the proposed graph of curves in relative values revealed the variability of the limiting pullout forces at different angles that deviate from the vertical, for different sand densities, surface roughness, and ratios of foundation dimensions.Slovak Higher Technical School, Bratislava, Czechoslovak Socialist Republic. Bulgarian People's Republic. Translated from Osnovaniay, Fundamenty i Mekhanika Gruntov, No. 4, pp. 25–27, July–August, 1988.     

Settlement of columns of forging-and-pressing plant

Conclusions 1. When designing the foundations of the load-bearing components of industrial buildings, it is necessary to take into account the dynamic effect of operating machinery, the type of soil, the nature of their stratification, and the groundwater region.2. In plants housing machines which apply dynamic loading, it is desirable to organize a systematic observation of foundation settlements with suitable instrumentation.Penza Civil Engineering Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 6–8, March–April, 1975.     

Full-scale investigations of the static deformations of foundations below 1000-MW turbine units at nuclear power plants under construction

Conclusions 1. Systematic geodesic observations of static deformations should be organized in constructing foundations for turbine units at high-capacity nuclear power plants; the results of these observations will ensure attainment of the required operational control data during construction and operation.2. During the design of these foundations, it is necessary to consider the installation of special surficial and deep marks for the organization of observations on bed settlement, beginning from the moment when the lower concrete slab is poured.3. In placing distributive cushions for the foundations, it is necessary to provide for a high quality of compaction within the bounds of the entire lower surface of the foundation and for careful geotechnical control.4. In designing foundations for turbine units on inhomogeneous beds, we should consider the difference in the rheological properties of the soils, the character and sequence of bed loading, and the variations in its hydrogeologic regime in order to exclude nonuniform settlements during equipment assembly and operation of the machinery.Dniepropetrovsk Civil Engineering Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 8–10, July–August, 1985.     

Regularities of development of settling of models of deep footings

Conclusions 1. The effect of relative penetration on the change in magnitude of settlement is substantial. With the same specific pressure on the base the settlement of the model decreases as the relative penetration increases.2. Published data on values of unit friction forces along lateral surfaces of deep foundations were confirmed. The maximum value of resistance along the side surface was 2 tons/m².3. It was established that the realtionship between the settlement of the model and its diameter is nonlinear. This is of great importance in working out a method for calculating foundations of deep footings from deformations especially if one considers that in this case the foundation carries substantial pressures and deforms under conditions of strongly developed shear regions.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 11–12, November–December, 1971.     

Effectiveness of using pile foundations in housing construction in Tyumen

Conclusions 1. Pile foundations of residential buildings in Tyumen under the usual soil conditions with the use of 30×30 cm prismatic piles and low monolithic grillage are, as a rule, ineffective.2. The use of pile foundations with a high grillage does not produce perceptible advantages and their technicoeconomic indices are close to those of foundations with a low grillage.3. The use of grillage-free pile foundations permits obtaining indices comparable with strip foundations at a pile length up to 8 m (working length 6 m).4. The economic effectiveness of pile foundations under conditions of Tyumen can be increased by using short piles of rational designs having an increased bearing capacity under the given soil conditions.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 4–6, May–June, 1977.     

Investigation of the bearing capacity of beds of foundations with an inclined base

Conclusions 1. Experiments showed that the total influence of the coefficients taking into account the inclination of the load in conformity with SNiP II-15-74 substantially underestimates the bearing capacity of beds. Correction of the values of these coefficients is possible, provided the accumulation of considerable experimental data.2. The bed bearing capacity does not depend on the sign of eccentricity in the plane of one of the axes of the foundation.3. For large inclinations of the load it is expedient to change to foundations with an inclined base, which permits increasing the bed bearing capacity as much as 40%.Scientific-Research Institute of Bases and Underground Structures (NII Osnovanii). Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 27–29, January–February, 1980.     

Determination of the depth of the deformation zone in the beds of annular foundations

Conclusions 1. The basic factors governing the depth H_a of the deformation zone in the beds of annular foundations are the area of the lower surface, the pressure, the ratio of the inside and outside radius, and the strength properties of the soils.2. The computational scheme proposed for determination of H_a in single-layer and multiple-layer beds of annular foundations makes it possible to account for soil indicators , c, and , and the average additional pressure on the lower surface, the geometric parameters, and the depth of embedment of the foundations.3. An annular foundation with r₁/r₂0.4 is recommended for computation as a foundation with a circular radius r₂.Odessa Civil-Engineering Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 7–9, July–August, 1988.     

Strengthening of foundations of deformed Maly Theater building in Moscow

Strengthening of foundations by the jet technique, which is not traditional in our country, has made it possible over short periods to carry out large work volumes without uncovering old foundations in the reconstruction of a deformed historic building.NIIOSP Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 22–25, January–February, 1993.