Investigation of the effect of a vertical surcharge on horizontal displacements and resistance of pile columns to horizontal loads

Conclusions

1. The principle of independence of the action of forces in the general case is not applicable to calculation of pile columns with relative embedment < 15. A vertical surcharge can somewhat decrease (in weak saturated soils) or increase (in clays of very stiff consistency) the resistance of pile columns to horizontal loads. In the investigated saturated soils, the bearing capacity decreased by no more than 15%, and in very stiff slump-prone soils it increased by a factor of 1.9.

2. Under equal conditions, pile columns with cantilevers absorb a 1.3–1.6 times greater horizontal load than prismatic.

3. When designing pile columns, the depth of their conditional embedment in the soil should be determined in conformity with the requirements of Instructions [12] and not by Table 12 in SNiP II-B.5-67*, since this leads to uneconomical reinforcement of the pile columns.

4. For pile columns of agricultural buildings a permissible crack width of 0.3 mm should be adopted instead of the 0.2 mm according to SNiP II-B.5-67*.