Bearing of Beams and/or Trusses on Piers and Columns

This mode is used to check the local strength of masonry and reinforced masonry at the areas of the beams and/or trusses bearing on piers and columns. The supported structure is a single beam/truss with a rectangular support base.

The size of the support base is limited by the bearing part of the structure or by the size of a steel packing plate at the support.

The check implements Sec. 6.44 of SNiP II-22-81 (Sec. 9.50 of SP 15.13330.2020) and recommendations of § 5.6 of the book by P.F. Vakhnenko.

The supporting structure is a pier of a wall or a column.

The peculiarity of the supporting structure is that the beam/truss is supported on a part of the masonry. There is no masonry above the support. A transverse reinforcement of the masonry with meshes can be made under the bearing part. The meshes are always distributed throughout the bearing area, the width of the pier, and the thickness of the wall.

You can select one of the following structural designs of the bearing area:

• directly on masonry;
• on a reinforced concrete cushion placed over the whole width of the pier;
• on a reinforced concrete cushion placed over the whole width of the pier through an aligning steel packing plate. The aligning packing plate occupies the whole width of the supported structure and can stick out.

The design load from the supported structure is specified as a concentrated force.

The check for local bearing, when the structure is supported directly on masonry, is performed for the masonry cross-section under the beam/truss; and if it is supported through a reinforced concrete cushion, the masonry cross-section under the cushion is used.

The dialog box of this mode contains the following tabs:

• General;
• Design;
• Reinforcement Data.

The General tab contains general data on the structure: the importance factor, age of masonry, working life, and data on the material — the types and grades of the stones/bricks and mortars used. All these data are described in the Materials section.

This tab is also used to specify whether the masonry below the support is reinforced or not reinforced. Depending on this, the user has options of bricks/stones for either not reinforced or reinforced masonry according to the general rules assumed in KAMIN.

The Design tab contains data on the column/wall, the load, the dimensions of the bearing area, the dimensions of the reinforced concrete cushion and the steel packing plate.

If there is a reinforced concrete cushion, you also have to specify data on the concrete.

The material and the thickness of the steel packing plate are not specified; the strength of the packing plate is assumed to be provided and is not checked.

The Reinforcement Data tab contains information on the reinforcement of the wall/column part below the bearing place.

This tab is identical to the respective one of the Axially Compressed Reinforced Columns  mode.

Limitations:

• if the structure is bearing on a wall, the check for axial compression below the bearing area uses a conventional cross-section of a column with greater side equal to a doubled pier width;
• in the check of masonry cross-section under the cushion, the resultant load is assumed to be applied at the distance of 1/3 from the interior edge of the cushion if there is no distribution packing plate, or from the interior edge of the packing plate if there is one;
• the check for tension of the masonry seams and of the reinforcement (if the masonry is reinforced below the bearing area) is performed only if the structure is supported directly on the masonry. The check is based on a principle given in § 5.6 of the book by P.F. Vakhnenko. Vertical seams of the masonry are always checked for tension. The obtained result is final for not reinforced masonry. The reinforcement of the reinforced masonry is checked for tension if the tensile strength of the masonry itself is insufficient.