Investigation of the impact of complex loading on the shallow foundations and the formation of a reactive layer in the soil base

Abstract

The effect of a complex load on the shallow foundations, features of pressure transfer to the base soil, formation of a reactive layer in the soil base, features of determining the dimensions of the sole of square and rectangular foundations, as well as the character of the reinforcement of the foundations and the dependence of the reinforcement of the foundation sole on the stress formed under it were studied . Particular attention is paid to the action of various combinations of complex loads on the foundation, which can lead to separation of the foundation sole and, as a result, to its overturning.
 The studies were carried out on the shallow foundations, columnar, made of monolithic reinforced concrete, on which metal columns rest and are fastened with the help of anchor (foundation) bolts. Buildings with a metal frame on such foundations are most often intended for warehouses, production or trade centers, agricultural facilities, service stations and many others.
 The effect of additional loads on the foundations during the verification of the accepted sizes of the soles of the foundations is shown. Such additional loads can be: the weight of the foundations, the weight of the soil on the ledges of the foundations, the weight of the backfill under the floor, the weight of the floor structure, the useful load on the floor, the weight of the foundation beam, the weight of the hanging walls, etc.
 Under the action of a complex off-center load at different moments of time, as a result of the action of various combinations of loads, under the sole of the foundations there are alternating stresses: average, maximum and minimum, which can lead to separation of the foundation sole. These stresses depend on the accepted dimensions of the foundation sole, and also affect their reinforcement. But the question arises: do the same stresses under the sole of the foundations affect the dimensions of the foundations and the determination of their reinforcement? The paper shows that to check the dimensions of the sole of the foundations, it is necessary to take into account the "standard" stresses under the sole of the foundations, and to determine their reinforcement - completely different stresses. Many scientists and designers are unaware of this fact. Therefore, incorrect consideration of the stresses under the sole of the foundations precisely to determine their reinforcement can lead to incorrect results, which will affect the reliability and cost of the foundations of the above buildings.
 The work presents methods of constructing foundations of shallow laying under the action of an off-center load with the aim of absorbing it.