The Analysis of Crossed Foundation Beams Lying on the Soil Base

To ensure uniform settlement of buildings and structures erected on a weak and heterogeneous soils, reinforced concrete foundations are designed from cross beams, or solid slabs. Currently, cross foundation beams and solid slabs are widely used in construction, like in the construction of high-rise buildings and many other engineering structures. In cross beams, at their intersection with an increase in load and stiffness, especially with an asymmetric load, in addition to bending moments and shear forces, the torques reaching large values can also occur, which are often not taken into account. The torques arisen at the knots of the crossed foundations may, in some cases, have a significant effect on their operation, for example, if the torques reach important values, then additional reinforcement must be placed in the foundations by stipulating the pressures arisen from them. For the correct selection of reinforcement, it is necessary to know the values of not only the bending moments, but also the torques arisen in the constructions. The existing methods of calculation often consider and calculate the crossed foundations as the constructions lying on a linearly deformable base. Besides most of them do not take into account the influence of torques. The methods of calculating the crossed foundations have been worked out by the author, by stipulating effect of bending moments on their working. There are given the formulas to calculate the bending moments, the system of equations is drawn up for linear and angular movements to define the unknown forces arisen at the knots of crossing the foundation beams. After determining these unknown forces, each beam is considered and calculated as a separate one, lying on a linearly deformable foundation.