General information.

The vocational school building was built according to standard design 2-03-19/58. Letter A (main building) – external and internal load-bearing brick walls, and an internal reinforced concrete frame, with floors and a covering made of reinforced concrete slabs; letter A1 - external and internal load-bearing brick walls, and an internal row of brick columns with ceilings and a coating of reinforced concrete slabs; letter A2 - external load-bearing brick walls covered with reinforced concrete slabs. The spatial structural rigidity of the object is ensured by the joint work of load-bearing walls and hard disks of floors and coverings. Structural elements of the building The foundations under the load-bearing walls of the facility are strip foundations made of prefabricated concrete blocks of the FBS type on a monolithic reinforced concrete strip, under the columns are columnar, monolithic. The walls of all sections of the building are made of plastic molded ceramic bricks using cement-sand mortar. The facade decoration of the walls is made of sand-lime brick. The total thickness of the basement walls, as well as the basement part - 640 mm, external load-bearing walls - 510 mm, internal load-bearing walls - 380 and 510 mm, enclosing walls of exits to the roof of the building letter A - 380 mm. In building letter A, internal load-bearing walls along axes B and B are present only in axes 3-4 and 6-7; in other areas, frame columns are used as load-bearing elements. In the load-bearing walls of letters A1 and A2, in the places where the trusses and ceiling elements support, pilasters with a section of 380x120 mm are installed. In the outer part of the wall letter A along the G axis there are decorative pilasters with a cross section of 1170x120 mm, starting from the level of the base and ending at elevation. . The columns of the main building are made according to standard design 2-03-19/58. They form an internal frame that absorbs loads from floor and covering elements. Two rows of columns are located inside all floors of the building along axes B and C with a pitch of 3,6-3,8 m and a distance between rows of 3,2 m. Structurally, they are rectangular reinforced concrete racks with the following characteristics: Type 1 (column K1): cross-section of the main rack 300x400 mm. It has two consoles in the upper part with a projection of 100 mm; Type 2 (column K2): cross-section of the main post 350x400 mm. It has one upper console with a projection of 100 mm. Additionally, on top of the columns there is a frame of 75x75x6 mm corners connected to each other by 50x5 mm strip steel. A chain-link mesh is welded on top of the frame, along which plastering and subsequent painting are carried out. The columns of the building, letter A1, are located in the basement along the 1/1 axis with a pitch of 3.6 m. They absorb the loads from the floor elements of the 1st floor. Structurally, they are rectangular reinforced concrete pillars with a section of 510x510 and 380x380 mm. The lintels for window and door fillings are factory-made lumber. In all Liters, monolithic reinforced concrete belts with a section of 380x220(h) mm are made at the covering level. Design documentation and results of engineering surveys for the overhaul of the facility: Floors and covering - made of multi-hollow reinforced concrete slabs with round voids 220 mm high, designed for a design load of 800 kgf/m2 (excluding the dead weight of the slabs). The outer rows are supported with one edge on the external load-bearing walls, and the other on reinforced concrete purlins measuring 3580x120x400(h) mm, laid on the frame columns. In axes 2-2/1÷B and 7/1-7/2÷B and 7/1-7/2÷B, monolithic reinforced concrete beams with a section of 450x400(h) mm are made on top of the columns. The middle row of slabs is supported by both edges on reinforced concrete frame purlins. In addition to the slabs, the ceiling structures of the basement and 1st-3rd floors contain small monolithic sections with a thickness of 200 mm. The roof is a combined one, made of fused materials over a cement-sand screed, laid over a layer of expanded clay concrete over a layer of vapor barrier laid over covering slabs. Flights of stairs are made of prefabricated reinforced concrete steps on steel stringers made of I-beams No. 18. Intermediate platforms are made of monolithic reinforced concrete on steel beams, similar to rolled metal stringers. Fire retardant treatment of metal structures - structural, plastering on a mesh followed by painting. On the marches and platforms there is a metal fence with wooden handrails 1000 mm high. The width of the flights is 1500 mm, the dimensions of the steps are 300x150(h) mm. Stairs for access to the ventilation chamber and to the roof - metal stepladders made of corners - 50x50x5 with rungs made of rods Ø12 mm. The partitions are brick, 120 and 250 mm thick, and gypsum blocks, 100 mm thick. Window fillings are metal-plastic. Door fillings are MDF and fiberboard, as well as metal blocks. Floors - ceramic tiles, linoleum. Interior finishing of walls and partitions - plaster, whitewash, painting with oil and water-based compounds, wallpapering, ceramic tiles. The ceilings are suspended “Armstrong” type and painted with water-based compounds. Engineering support for the building is from city networks. Results of the building inspection As a result of a detailed (instrumental) inspection of the building's building structures and verification calculation data, the following was established. Foundations To assess the technical condition and geometric dimensions of the building’s foundations, 7 pits were drilled in places where work could be carried out. Design documentation and results of engineering surveys for major repairs of the facility: As a result of inspection of the foundations in the opened pits, the following characteristics were established: the foundations for the external load-bearing walls of the main building section with a basement are made of three rows of FBS foundation blocks 600 mm wide, laid on a monolithic reinforced concrete strip with a section of 1700x400 (h) mm. Next, on top of the blocks there is brickwork 640 mm thick, on top of which there is a monolithic reinforced concrete belt with a section of 500x300(h) mm. The depth of the sole relative to the ground surface is 2.2-2.8 m; the foundations for the external load-bearing walls of the main building section without a basement are made of three rows of FBS foundation blocks 600 mm wide, laid on a monolithic reinforced concrete strip with a section of 1700x400(h) mm. On top of the blocks there is a monolithic reinforced concrete belt with a section of 500x300(h) mm. The depth of the sole relative to the ground surface is 2-2.2 m; the foundation under the internal load-bearing walls of the stairwells of the main building with a basement is made of a monolithic reinforced concrete strip with a section of 1380x500(h) mm, on top of which is brickwork 380 mm thick. In masonry at elevation. -0.600 a monolithic reinforced concrete belt with a section of 380x300(h) mm was installed. The depth of the sole relative to the ground surface is 2.2-2.8 m; The columnar foundations under the columns of the reinforced concrete frame of the main building are monolithic and consist of two stages. The cross-section of the lower step (base) is 2500x2500x450(h) mm, the upper one is 1300x1300x600(h) mm. At the base of the foundations there is a 100 mm thick concrete footing. The depth of the sole relative to the ground surface is 2,8-3,5; foundations for external load-bearing walls, letter A1, are made of two rows of FBS foundation blocks 600 mm wide, laid on a monolithic reinforced concrete strip with a cross-section of 1400x400(h) mm. Next, on top of the blocks there is brickwork 640 mm thick, on top of which there is a monolithic reinforced concrete belt with a section of 500x300(h) mm. The depth of the sole relative to the ground surface is 2,2-2,6 m; columnar foundations under columns letter A1 are monolithic and consist of two stages. The cross-section of the lower step (base) is 1700x1700x300(h) mm, the upper one is 800x800x400(h) mm. The depth of the sole relative to the ground surface is 2.5-2.9 m; foundations for external load-bearing walls, letter A2, monolithic two-stage. The cross-section of the lower step (base) is 1400x300(h) mm, the upper one is 600x1650(h) mm. The depth of the sole relative to the ground surface is 2.1-2.4 m. According to the results of laboratory tests, the strength of concrete is as follows: monolithic reinforced concrete tapes - B20; Design documentation and results of engineering surveys for major repairs of the facility: monolithic structures of columnar foundations - from B20 to B22.5; foundation blocks - from B15 to B20. During the inspection of the foundations, the following was recorded: the above-ground and basement parts of the foundations, consisting mostly of brickwork, were plastered for protection from external influences. On certain sections of the facades in axes 1-9 and D-A, the plaster has multiple damages; the brickwork of the foundations is buried in the ground without waterproofing measures. This circumstance contributes to the soaking and destruction of the brick. In certain rooms of the basement of the main building and letters A1 there is soaking of the walls; natural lighting of the basement rooms, letter A and letter A1, is provided through window openings in the walls, fenced with pits. There are no canopies above them, which allows moisture to get inside and soak the walls; vertical cracks with an opening width of 2 and 3 mm in the basement wall, letter A, in axes 2/3-4÷G; horizontal cracks with an opening width of 3 and 5 mm in the basement walls of letter A in axes 5/B-G and 4-4/1÷G; horizontal crack with an opening width of 3 mm in the internal wall of the basement, letter A, in axes 3-4/B; vertical crack with an opening width of up to 3 mm in the corner of the internal walls of the basement letter A in axes 4/B; The foundations of the main building, due to the construction of the basement only under its part, are made at different levels, which, due to the different loads on the foundation, contributes to the appearance of excessive stress in the supporting structures. When conducting an inspection of above-ground load-bearing brick walls, cracks and deformations were recorded in them, indicating either insufficient rigidity of the foundations or a decrease in the load-bearing capacity of the foundation.