Investigation of force redistribution in the foundation slab of complex configuration in low-rise buildings

Abstract

A study of the redistribution of forces in the foundation slab of a complex configuration in the plan for the installation and non-installation of deformation seams between blocks of low-rise building using numerical simulation by the finite element method (FEM). Two variants of the foundation slab are considered - with the installation and non-installation of deformation seams.
 Due to the large difference in loads in different rooms and areas of the building to prevent uneven deformation of the bases as a foundation was adopted monolithic reinforced concrete foundation slab type with a thickness of 400 mm. The frame of the building is monolithic reinforced concrete with vertical load-bearing elements in the form of columns, pylons and walls, which are united by monolithic floor slabs, which create stiffness disks.
 The basis for the slab foundation are sandy soils dusty and small, medium density with lenses of plastic sands.
 After the calculations, the stress-strain state (SSS) of the foundation structures of the building was analyzed, namely: subsidence of the foundation slab, redistribution of bending moments in the foundation slab in the X and Y directions and selected the appropriate area of working reinforcement of the foundation slab. As a result of calculations, it was found that the presence of deformation seams significantly affects the redistribution of forces in the foundation slab of complex configuration in low-rise buildings. When installing them, there is an increase in bending moments in areas away from the junction of building blocks from 5% to 20%. A significant increase in bending moments occurs in the joint zone of the building blocks when installing deformation seams. In these areas, an increase in bending moments from 10% to 3 times, which significantly affects the cost of reinforcement of the foundation slab. It is also shown that the device of deformation seams practically does not affect the maximum values of subsidence of the foundation slab.
 Therefore, for low-rise buildings it is recommended to arrange a version of the foundation slab without deformation seams.