architectural solutions. Space-planning solutions

The project for the reconstruction of an existing non-residential building provides for the placement of a center for providing assistance to citizens without a fixed place of residence. The existing building, built in 1917, is rectangular in plan, 33,9 X 7,0 m in size, brick, four-story, without a basement, with a cold attic. The height of the building to the top of the cornice along the front facade is 13,35 m. The reconstruction project provides for: dismantling of existing partitions, window and door blocks; dismantling of existing wooden floors, rafters and roofs; construction of new interfloor floors, rafters and roofs with an increase in the height of the roof ridge in the yard up to 16,10 m., in the zone of the elevator node - up to 17,30 m.; the construction of partitions and the arrangement of additional openings in the outer walls in accordance with the adopted planning decisions; an extension to the outer wall along axis B from the side of the courtyard facade of the elevator unit and two evacuation external stairs of the 3rd type; installation of new window and door blocks; superstructure in the attic level of the existing staircase; insulation of external brick walls on the front side with facade mineral wool boards with plastering and painting with facade paints. On the ground floor, it is planned to place the entrance group of premises, a complex of premises for the reception of citizens, amenity premises and loading the dining room, premises for accommodating various engineering equipment. On the second floor - a quarantine department, office space, a complex of dining rooms. On the third floor - rooms for temporary stay of citizens with sanitary facilities and showers. On the fourth floor - administrative and service premises, ventilation chambers. The attic is cold, not heated. For vertical communication between the floors, a stairwell H2 is provided for the entire height of the building and a stairwell L1 from the 1st to the 2nd floor, having access to the street, a passenger elevator with a capacity of 400 kg, a passenger-and-freight elevator with a capacity of 1000 kg, designed for transportation and evacuation MMGN. For evacuation from the upper floors, two external open staircases of the 3rd type are provided. The roof is sloping, shed, covered with polymer-coated metal roofing sheets and an external organized drain. Partitions are plasterboard sheets installed on a metal frame, in rooms with a wet regime and technical rooms - brick. The filling of window openings is made in metal-plastic window blocks with double-glazed windows. Interior decoration is carried out in accordance with the functional purpose of the premises. Finishing of facades: socle - facing decorative concrete stone; the walls of the above-ground floors are plastered with facade paints. The project provides for measures to ensure conditions for the life of people with limited mobility: an external open ramp for safe ascent to the level of the first floor, an elevator for lifting visitors to the institution on stretchers and wheelchairs, sanitary facilities for the disabled.

Structural and space-planning solutions

The structural scheme of the building is frameless, with load-bearing longitudinal and transverse walls. The spatial rigidity of the building is ensured by the joint work of brick walls and floor discs. Foundations - tape rubble on lime mortar. The walls are brick, made of red full-bodied clay bricks on lime-sand mortar. Lintels - wedge-shaped brick and metal. Interfloor and attic floors - on metal beams with plank filling. Staircase - stone steps on metal kosour. Roof - from galvanized roofing steel on wooden inclined rafters. The technical conclusion on the inspection of the building structures has been completed. A survey of the foundations with a fragment of the pits found that the foundation is located in water-saturated soil, there is a leaching of the solution from the rubble masonry, which led to uneven settlement. Horizontal waterproofing on the edge of the foundation was not found. At the base of the foundation lie fine sands saturated with water. Signs of uneven subsidence of the foundation soils under the foundations were established, which could be caused by a combination of reasons (reconstruction measures carried out during operation; leaks from engineering networks; fluctuations in the groundwater level). According to the results of static probing of soils on the site, carried out by Trust GRII in 2008, it was established that the building foundations are based on sands with a frontal resistance of 40 kg/cm2, which corresponds to sands of medium density (e = 0,75, E = 180 kgf/cm2, angle internal friction 28°), saturated with water. The design resistance of sands does not exceed 2 kg/cm2. The sands are underlain by soils containing organic matter with a frontal resistance of 5-6 kg/cm2. Ground water was found at a depth of 130 cm from the ground level. The verification calculation found that, taking into account the increase in load during the reconstruction of the building, the foundations require reinforcement. An increase in loads on the walls of a building without strengthening the base and foundations is unacceptable. In the laying of individual brick lintels and inter-window belts, inclined cracks of a sedimentary nature of ancient origin are observed with an opening of up to 0,1-0,3 cm. The masonry of the wall along the “B” axis in the zone of the chimney channel is in an unsatisfactory condition, in some areas it is in an emergency condition. The strength of the brickwork of the walls, measured by the ultrasonic device UK 1401 at 15 points, is in the range of 4,1-8,4 kg / cm2, of which the strength of less than 5,0 kg / cm2 was noted at one pier in the wall along the “A” axis. Corrosion of metal beams - more than 30% in cross section. The plank filling is affected by rot, collapsed in sections. Stringers, platform beams must be cleaned of corrosion products and coated with an anti-corrosion compound. The rafter legs are affected by wood rot at 1/3 - 1/2 of the section, the crate is affected by rot. At the time of project development and during the execution of work at the facility, a deviation of the outer wall along the “B” axis from the vertical was detected. For this reason, an additional survey of the building was carried out. Prepared a conclusion on the technical condition of the wall, foundation and foundation soil of the building from 2010. According to the results of the survey, it was recorded that the tilt of the building significantly exceeds the permissible value and amounts to 0,019. The absence of characteristic cracks on the end walls of the building confirms the fact that the building tilted along two axes A and B simultaneously. Based on TSN 50-302-2004, the building belongs to the 3rd category of technical condition. It was established with a fragment of the pit that under the foundation the soil and foundation were reinforced by injection through boreholes. The work was carried out by a contractor: injection of cement mortar through boreholes with a diameter of 94 mm through the body of the foundations. The hole pitch is 500 mm in a checkerboard pattern. Soil injection was carried out to a depth of 1,2 m below the base of the foundation. At elev. 0.000, a monolithic reinforced concrete slab 250 mm thick was made, the reinforced slab was anchored through metal I-beams - cantilever beams I No. 18 according to the project. These measures to strengthen the base and foundation, the installation of the slab increased the stability of the building. The project provides for: performing a horizontal anti-capillary cut-off by injection through boreholes. Hole diameter d = 25 mm with a step of 250 mm; repair of brickwork of walls in the areas of cracks and the location of chimneys; reinforcement of brick lintels and installation of new lintels from rolled profiles in newly arranged openings in existing walls; dismantling of existing and installation of new floors from metal rolling I-beams 25B1. A profiled sheet is laid along the lower shelves of the beams, on top of which a backfill of expanded clay is arranged. A reinforced concrete monolithic slab is made along the upper chords of the beams. From below, the corrugated board is hemmed with two layers of fire-resistant gypsum board; dismantling of the existing roofing system and installation of a new one along metal beams. Coating - from roofing steel with a polymer coating; replacement of stair railings, cleaning of stringers from corrosion products, followed by plastering over the mesh with cement mortar, repair of stair steps. Outside, along the facade, two evacuation stairs made of rolled metal are provided for the entire height of the building; protection of metal structures against corrosion in accordance with SNiP 2.03.11-85. Taking into account the recommendations of the opinion of CJSC "Beskit" dated 2010. a specialized subcontractor developed the construction of foundations for an extension and an elevator shaft by using bored and split piles. Borehole d-325 mm, L = 12 m, N - 35 tons. split piles for an elevator shaft d-325 mm, L = 6 m. The pile foundation rests on EGE-5 stratified refractory loam (volumetric weight - 2,00 g/cm3, deformation modulus 100 kgf/cm2, internal friction angle 19°). The draft of the extension will be 7 mm. Thus, the extension, located on the outer side of the wall of the existing building, acts as a buttress. The construction of the extension - with brick enclosing load-bearing walls and reinforced concrete monolithic floor slabs, coatings. The walls of the structure are designed from solid brick grade 150 and mortar grade 50, frost resistance grade is not lower than F50. Interfloor ceilings and roofing - monolithic reinforced concrete slabs 150 mm thick, concrete of class B20, F50, W4 are reinforced with separate rods. Elevator shafts - monolithic with a wall thickness of 150 mm, concrete of class B20, grade F-150 for frost resistance and W4 for water resistance, reinforced with separate reinforcing bars. During the execution of works, it is planned to organize geodetic observations of the building settlements and install beacons on the cracks, monitor the dynamics of the building settlement and the development of cracks. Geodetic measurements of deformations during construction should be carried out at least once every two weeks. Approximate terms of monitoring - from two to five years. Geodetic measurement of deformation during the construction and operation of the building should be performed at least once a month during the first year of operation, then at least once a quarter. In this case, the maximum additional settlements of the existing building should not exceed 2 cm, the relative difference in settlements should not exceed 0,001, and the heel should not exceed 0,002.