Information about the functional purpose of the object

The residential building was built in 1972 according to the standard project 1 Lg-600A, developed by the institute JSC "LenNIIproekt". Panel building type, nine-storey with a basement, has an extended shape in plan and the main facade faces the street. The outer walls of the building are made of hinged aerated concrete panels with a thickness of 160-240 mm. At the top, the thermal contour of the building is closed by aerated concrete floor slabs over the 9th floor with a thickness of 240 mm and a superstructure of aerated concrete panels with a thickness of 240 mm above the stairwell, including the machine room of the elevator. All external walls are plastered and painted on the inside, in most apartments they are covered with wallpaper, on the outside they are painted with hydrophobic paint. In the stairwell there is a passenger elevator with exits to the floor areas and a garbage chute with a waste bin at intermediate platforms across the floor. A section of the building is served by one passenger elevator. The room of the missing freight elevator is used for storage rooms for apartments adjacent to the mine. The structural scheme of the building is frameless, two-span, with transverse load-bearing walls installed in increments of 3 and 3,3 meters. The internal longitudinal and transverse load-bearing walls are made of reinforced concrete panels with a thickness of 140 of concrete grade "200". Interfloor ceilings are flat reinforced concrete made of concrete grade "200" with a thickness of 140 mm, mainly the size of a room. Attic transverse reinforced concrete wall panels have a beveled top side to create a roof slope and square openings for passage. The interior walls of the staircase are reinforced concrete panels. Landings and flights - prefabricated reinforced concrete from concrete grade "300". The elevator shaft is made of prefabricated reinforced concrete blocks of square section, installed on top of each other. The load-bearing structures of the roof of the building are ribbed panels, on which a soft carpet of roofing material is laid. The spatial rigidity of the building is provided by the joint work of the longitudinal and transverse walls and ceilings. The compatibility of the work of walls and ceilings must be ensured by platform joints and reliable connections between structural elements.

Information about the engineering support of the object

Heat supply of a residential building is carried out from a centralized source. Design parameters of the coolant (water) for the heating system: 95-70 "C. The existing heating system of the building is one-pipe vertical with top filling. Pipelines of the heating system - steel water and gas pipelines (according to GOST 3262-75 *). The project provides for the replacement of heating devices that have become unusable as a result of a fire with steel panel radiators of the SotrasA series manufactured by Rigto. Domestic and drinking water supply is centralized. The source of water supply is external public water supply networks. Hot water supply is centralized. The source of hot water supply is external heating networks. For hot water supply, closed water intake from the heating network through heat exchangers is adopted. Hot water is prepared from cold water. The hot water supply system is closed, with water supply from the ITP, located in a separate room in the basement. Domestic sewage from sanitary appliances is discharged into the external sewerage network through an existing riser with a diameter of 100 mm. The power supply of a 9-storey residential building is an existing one, carried out as a separate project based on a standard project developed by JSC LenNIIproekt. The power supply of electrical receivers of a residential building is provided from an industrial network with a voltage of ZNPE -50 Hz, 380/220V.

Results of the survey

In accordance with the minutes of the meeting of the headquarters for the elimination of an emergency at the facility, in order to prevent further collapse and carry out priority safety and emergency measures, a preliminary survey of the technical condition of the main load-bearing structures of the emergency section of the building was carried out. The building was damaged as a result of an explosion that occurred in the staircase elevator on the floor. From the technical report on the survey it is known that: at the level of the 7th and 8th floors of the stairwell (l.c.), the outer wall aerated concrete panels completely collapsed; at roof level l.k. two pavement slabs collapsed, while one of the slabs hung on the ventilation pipe of the garbage chute, the other collapsed and lies on the landing of the staircase; at roof level l.k. received significant damage to the side walls, coating and roofing over the stairwell and the engine room of the elevator; at the level of the intermediate platform l.k. at the entrance to the attic, a transverse crack formed with an opening of 0,2 mm. The metal staircase that leads to the attic and the roof was practically undamaged; at the level of the 1st and 2nd floors, the asbestos-cement pipe of the garbage chute was completely destroyed; above the 4th floor, the hinged outer wall panels that did not collapse received a significant movement (up to 150 mm) outward of the building from the wall plane with the destruction of fasteners; the glazing of the windows on the l.c. was completely destroyed. and partly wooden bindings. at the level of the 9th floor in a three-room apartment, 1 wall panel in the kitchen received significant damage in the form of outward movement up to 150 mm. It is necessary to restore the wall panel in the kitchen, as well as to restore and fix the connections between the wall panels of the outer walls. at the level of the 9th floor in a one-room apartment 1 in the room and in the kitchen, the attic floor of prefabricated aerated concrete slabs received damage characteristic of fire in the form of a change in the structure and color of concrete, unacceptable cracks and deflections up to 10 mm. Wall outer panels in this apartment received a shift from 20 to 50 mm outside the building. The inner walls are heavily smoked and cannot be visually inspected, but there are no characteristic bulges and significant cracks. All joinery and floor coverings are completely damaged by fire. The entrance metal door was torn off, plumbing fixtures were damaged. It is necessary to restore and fix the connections between the wall panels of the outer walls. At the level of the 9th floor in one-room apartment 2, in the machine room of the elevator, in the upper part of the wall of the pantry adjacent to the elevator shaft, an opening was formed overlooking the attic. The opening must be sealed in the process of creating a new wall structure that encloses the top of the stairwell and the machine room of the elevator. IN the same wall has two vertical cracks with an opening of up to 0,4 mm and a slight movement out of the plane; at the level of the 9th floor in a three-room apartment No. 179, no significant damage was observed. The apartment has recently been renovated and all the walls and ceilings are lined with plastic and mirrors. The reinforced concrete blocks of the elevator shaft on some floors have minor damage in the form of oblique cracks with an opening of up to 0,3 mm at the top of the doorways and a slight (up to 10 mm) bulging of the side walls bordering the apartments and the presence of vertical cracks in them with an opening of up to 0,2 mm. The wall of the elevator shaft at the level of the 7th floor. Elevator doors with wooden mortgages were torn out, sloping cracks above the opening.

Findings from the Survey

It is required to dismantle the aerated concrete panels enclosing the upper part of the staircase, including the elevator machine room. Since these panels (both wall and stairwell covering slabs) are part of the thermal contour of the building, it is necessary to replace them with structures that provide sufficient thermal protection for the building. The proposed design of the new wall railing at the top of the staircase, including the elevator machine room, is a metal frame sheathed with DSP sheets, between which there are three layers of 50 mm Rockwool Acoustic Butts insulation. It is necessary to dismantle the affected fencing structures of the outer walls of the stairwell within 4-9 floors. In place of the resulting opening, hang a stained-glass structure filled with single-chamber double-glazed windows and stained-glass sandwich panels. The segmentation of stained glass elements should be performed in accordance with the existing glazing of the staircase. Maintain the color scheme of the walls. Renovation of apartments 1,2 is necessary. Each apartment has a common room, bedrooms, hallway, kitchen, separate bathroom, pantry. The height of the floor from floor to floor is 2,7 m. The height of the living rooms is -2,56 m.

Priority activities

The main goal of the implementation of priority emergency response measures is to assess the destruction of the main load-bearing structures of the emergency section of the building caused by the explosion and make technical decisions to eliminate the current emergency (with the subsequent restoration of the destroyed structures for further operation of all the apartments of the building affected by the explosion). To prevent spontaneous collapse of building structures and maintain the stability of the building's load-bearing elements, the following measures are necessary: Installation of inventory support towers PERI PD 8 under the landings from the first to the ninth floor inclusive. Connect the support towers to each other along the top with channels [20, 2700 mm long. Under each landing it is necessary to install two inventory support towers. Installation of inventory racks PERI PEP 20 under flights of stairs from the first to the ninth floor inclusive. Connect the support posts to each other along the top with channels [20, 2700 mm long. Under each flight of stairs it is necessary to install 6 inventory racks. Racks are installed in two rows along the width of the flight of stairs, in one row there are three racks. Installation of inventory racks PERI PEP 20 under the ceiling above the ninth floor in an apartment damaged by an accident. Connect the support posts to each other along the top with channels [20, 6000 mm long. Shelter with a solid flooring of wooden shields 50 mm thick of surfaces under the floor to be dismantled. Organization of monitoring of the building and buildings in the 30 meter zone. To do this, prior to dismantling, it is necessary to establish control marks on the structures to be preserved and monitor their stability in accordance with the monitoring rules according to a specially developed program agreed with the general designer. Reinforce the ceiling above the ninth floor in apartment 177 and the ceiling of the landing above the ninth floor with metal beams. PA decision was made to resettle only the tenants from the apartments directly adjacent to the source of the explosion. In view of the presence of the threat of collapse, it was decided to use the most gentle technologies during emergency response work, excluding vibration and dynamic loads in the form of shock wave propagation. To reduce the threat of collapse of a residential building, work to eliminate accidents was carried out around the clock and non-stop, using a reduced work shift of 6 hours each, due to increased physical exertion and psychological impact. There are conditions at the facility that affect the performance of work, due to the following external factors:residential building-inhabited; Odanger of collapse in the working area and the entire building; Ogreen zone storage; nthe possibility of storing materials; Pmanual construction work; Withurgency of work, round-the-clock operation; Pthe duration of the shift is not more than 6 hours; Proizvodstvo work in three shifts. Therefore, correction factors are applied to the norms of labor costs and the operation of machines (including the wages of machine operators), taking into account the influence of the conditions for the production of work.