Basic design decisions. Structural and space-planning solutions.

The multi-apartment residential building was built in 2003 in the existing residential development according to the project documentation. Building inspection completed. The survey found that the building was built in three sections, 14-15-16 storey, according to the cross-wall design scheme. The load-bearing structures of the building skeleton are made of monolithic reinforced concrete. The spatial rigidity of the building sections is ensured by the box-shaped structure of the basements and the joint work of longitudinal and transverse reinforced concrete walls, united by floor disks. The outer walls of a building are of two types: load-bearing and non-bearing. Load-bearing external walls - from monolithic reinforced concrete with external insulation and finishing with a layer of bricks 250 mm thick. Non-bearing external walls - two-layer, with an inner layer of aerated concrete blocks 375 mm thick and an outer layer of hollow bricks 250 mm thick. In the working drawings developed, the brickwork of the facing layer of the facade walls was provided as non-bearing, with floor-by-floor support on floor slabs and a steel corner fixed to the end of the slabs. This was not confirmed by the survey, but it was found that the brickwork is self-supporting. The survey found that the general condition of the external walls of the building is operational, the condition of the brickwork of the enclosing external walls of the loggias on the technical floor in section 2 and section 1 is limited-operational, in section 3 - emergency. In the brickwork, cracks with an opening of up to 20 mm were revealed, which were formed due to insufficient reinforcement of the brickwork and the absence or insufficient anchoring of the brickwork to reinforced concrete. Ceilings and coverings - from monolithic reinforced concrete with a thickness of 200 and 160 mm, along the outer perimeter with thermal breaks - are in working order. The foundations - slab grillages 600 mm thick on a pile foundation - are in working order. In the conclusions of the survey, it was found that the building as a whole belongs to the second category of technical condition. The appearance of additional deformations associated with uneven precipitation during the deterioration of the geotechnical situation in connection with the construction of a building on an adjacent site is excluded. However, the survey recommended that prior to the commencement of construction and installation work on the adjacent site, the strengthening of emergency structures should be performed. The building has already been surveyed. In 2011, in order to develop design documentation for the construction of a multi-storey residential building with an attached underground parking lot at the address: Moskovskoe shosse, 16, letter A, a survey was carried out, and no failure rate of the structures was identified. The building was recognized as the second category of technical condition. Structural section of project documentation (working documentation code МШ-16/13-01-КМi1 "Metal structures") for strengthening the brickwork of the external walls of the loggias of the technical floor in section 2 in the axes "23-28 / U-F" and in section 3 in axes "7-12/H-O" developed. The design, working documentation provides for the strengthening of the brickwork of the arches of the enclosing walls of the loggias of the technical floors with the installation of a frame for framing the arch arch and a one-sided steel clip. Frame - from paired corners 70 x 8 mm, connected by overlays from sheet steel 8 mm thick. The clip - from rolled corners 70 x 8 mm and 50 x 5 mm - is designed from the inside of the arch and attached to the masonry with through studs with distribution plates. The reinforcement structure is attached to the floor slabs with Hilti HSL-3 M10/20 mechanical expansion anchors: along the edges of the loggias - through steel posts made of 20P rolled channels, in the span - through steel strands with a diameter of 12 mm (4 pcs. to the arch). The design load on the tie - 4 kN will not exceed the bearing capacity of the tie - 11,9 kN. Rolled stock - from C245 steel with anti-corrosion paint and varnish coating. Reliability of fastening of anchors to reinforced concrete is confirmed by test results. With a design load on the anchor of 4 kN, the pull-out bearing capacity of the anchor was 13 kN. To ensure the stability of the brickwork of the arches during the period of work to strengthen them, the design documentation provides for the installation of temporary fastening. It is planned to install a steel fachwerk from racks and beams from closed bent-welded profiles from the outside of the wall.

Structural solutions of the building

The KM section was developed on the basis of the architectural and technological assignments of the relevant parts of the project and in accordance with the current building codes and regulations. The level of responsibility of the building is II, which is taken into account in the calculations of building structures by the reliability factor for responsibility - 1. The loads are taken in accordance with [1] through the brick. The vault of the arch is framed by corners 50x5. The structure is attached to two metal posts made of 70P channel, fixed with expansion anchors to monolithic floor slabs. The top of the structure is fastened through metal corners 8x70 to the monolithic slab of the building frame with expansion anchors. The construction material is C8 steel. For the duration of the work to strengthen the brickwork, it is necessary to perform temporary reinforcement on the outside of the building. Temporary reinforcement consists of 20 racks fixed in the lower part to a monolithic slab and pulled by strands to the outer edge of the brickwork. The strands are fastened with expansion anchors to a monolithic floor slab.