Architectural and space-planning solutions

The design documentation provides for the construction of a residential seven-story two-section residential building with built-in premises in place of the dismantled building. The residential building is designed with a basement and an attic floor. The maximum dimensions of the building in plan are 46,765 x 21,45 m, height - 24,7 m to the roof ridge. The building is designed: in the basement - underground parking for 16 parking spaces and facilities for engineering support of the building; on the ground floor - entrance groups of the residential part of the building, office premises, an exhibition hall of children's creativity, a fire station, dispatching and video surveillance room, an entrance to an underground parking lot and a room for cleaning equipment; on the other floors - residential apartments. The building provides for the installation of two passenger-and-freight elevators with a carrying capacity of 1000 kg. The roof of the building is made of roofing steel on metal rafters with an external organized drain. Exterior finish of the building - decorative facade plaster, clinker tiles, natural granite. The project documentation provides for measures to ensure the living conditions of people with limited mobility in accordance with SNiP 35-01-2001.

Constructive decisions

Structural scheme of the building. The constructive scheme of the building is frame-wall. The spatial rigidity and stability of the building is ensured by the presence of stiffening cores - monolithic walls of stair-elevator units, rigidly connected by monolithic ceilings. Bending moments in load-bearing walls and columns arise only as a result of the adjoining floors that differ in spans. The foundation of the building is a slab-pile foundation, consisting of individual piles for columns and rows of bored piles for load-bearing walls, united by strip grillages and a 300 mm thick slab. To evenly distribute loads and increase the overall rigidity of the building frame, external monolithic walls of the basement floor 300 mm thick, rigidly connected to the foundation slab, are used. Stiffening belts are created in the alignment of columns due to concentrated discrete reinforcement, and then the design scheme of beamless floors becomes similar to the operation scheme of floors contoured by ribs. The calculation of the building structures was carried out using the Sofistik program version 11.1, taking into account the joint work with the pile foundation. As a result of the calculation of the spatial scheme, the following were determined: the overall strength and stability of the supporting structures of the building; maximum and relative settlements of the base from the most unfavorable combinations of loads; forces in monolithic reinforced concrete columns, walls and floor slabs. In accordance with the forces obtained, the strength and deformability of the frame elements were checked. Calculations have shown that stresses, deformations, displacements, crack openings do not exceed the corresponding limit values ​​of building codes for designing structures or foundations. The calculation and design of the foundation slab and frame elements were carried out in accordance with the requirements of SNiP 2.01.07-85*, SNiP 2.02.01-83, SP 50-101-2004, TSN 50-302-96, TSN 50-302-2004, SNiP 52-01-2003 , SP 52-101-2003. Pit anchoring. Architectural and planning solutions provide for a deep parking lot, 3,6 m deep from the ground. When building in conditions of dense urban development, it is important to limit the deformations of the surrounding buildings to values ​​that exclude the possibility of damage to its structures or deterioration in operating conditions, and, consequently, the choice of a pit enclosure option. It is necessary to create a closed watertight circuit with a distance of at least 2 m from existing buildings. It is not allowed to lower the groundwater level from the side of existing buildings. Most of the surrounding buildings belong to the third category of technical condition with allowable additional precipitation according to TSN 50-302-2004 2cm. To ensure this requirement, sufficiently rigid fencing structures are required, as well as a rigid system of spacers that keeps the excavation fencing from moving. The presence of thixotropic soils under the foundations of existing buildings, which turn into a floating state under the action of dynamic loads, completely excludes the technology of installing sheet piling by vibration or impact driving. In the project, it was decided to use the ARCELOR AZ 37-700 sheet pile as the excavation fence, driven by the GV-ECO700S installation with a maximum pressing force of 1100kN (112t.). The project provides for a single immersion of the sheet pile, without subsequent extraction. In our case, with a pit depth of up to 5 m, the stiffness of the arcelor AZ 37-700 sheet pile is sufficient to ensure the strength and deformability of the fence, which is confirmed by the calculations presented in the Geotechnical justification of the project. In addition to the fencing technology, the technology of digging a pit is of no small importance. The project adopted a variant of the construction of the pit using the "topdown" technology (top-down). In this case, the floor disk, which is made on the ground before excavation of the pit, acts as a spacer system. The overlap is carried out with the leaving of technological holes through which the soil is excavated. Soil development in this case should be carried out with small-sized equipment. The piles are partly the columns of the basement floor. The depth of the pit enclosure should be at least 19 m from the ground. Before carrying out work on the installation of sheet piling, it is necessary to carry out work to strengthen the foundations and soil of the base of adjacent existing buildings according to a specially developed project. The sequence of work. 1. Strengthening the foundations of existing buildings. 2. The device sheet piling. 3. The device of the pile field. 4. The device of a monolithic reinforced concrete. ground coverings. 5. Excavation of the soil. In accordance with the performed Geotechnical justification, when carrying out these activities, the impact of new construction on adjacent buildings and buildings in the 30th zone from the construction site is minimally acceptable. Settlement of buildings adjacent to the construction site within the allowable 2 cm. Foundations. At the base of the building being designed, weak clay deposits (IGE 3, 4) are plastic and fluid. Clay soils have significant compressibility and low water permeability; large uneven subsidence of the base due to additional loading can last for a long time. In this regard, the variant of the pile foundation was taken as the basis, transferring the load from the building to the lower relatively low-compressible soil layers. Light silty gray loams with gravel, pebbles with interlayers of sand with hard-plastic sandy loams, occurring at a depth of 7-11 m, are taken as the carrier layer. The project adopted bored piles in a casing pipe d 640 mm 30 m long from the surface of the earth. The design load on the pile is determined by calculation according to SP-50-102-2003 and is assumed to be 280 tf. Concrete class B25 W8 F100 longitudinal reinforcement Ø18 A400 and clamps Ø8 A240 . The final bearing capacity of the pile is determined after pre-design testing of piles with a static indentation load. The project provides for the production of two bushes of experimental piles. Bush 1 - pre-design test to determine the bearing capacity on the ground and the possibility of immersion to the design depth. Bush 2 - for control pre-construction testing. Bush 1 (pre-design test) test pile No. 6, anchor piles No. 7, 8, 9, 10 30 m long from the ground. Bush 2 (control test) test pile No. 1, anchor No. 2, 3, 4, 5, 30 m long from the ground. Based on the results of the pre-design testing of the N6 pile, the diameter and length of the pile can be corrected. Piles shall be tested with static load in accordance with the requirements of GOST 5686-94, GOST 19912-2001. The static load on the piles must be at least 370 tf, or brought to a settlement of at least 50 mm. Monolithic basement slab made of B25, W12 class concrete, 300 mm thick at elevation -3,750(rel.). Under the slab, the following preparation is carried out (from bottom to top): geotextile - 1 layer, crushed stone - 100 mm, foam insulation 50 mm (from freezing of the soil for the period of work), a 50 mm screed is made of concrete class B7.5 on foam plastic. To ensure the watertightness of the slab, waterproofing dowels made using the “Waterstop” technology are laid in the working seams of concreting and in the seam with the outer wall. Ground floor. The outer walls of the basement are monolithic, made of B25, W8 class concrete, 300 mm thick. The internal walls of the basement are monolithic, made of class B25 concrete, 200 mm thick. Basement columns - pile-columns made of B25 class concrete, round with a diameter of 450 mm. Beamless type parking floors made of class B25 concrete 220 mm thick. Walls and columns above el. 0.000 External non-bearing walls, floor-by-floor supported on ceilings, are made of hollow ordinary brick of grade M150 F35 on cement. sand r-re M100 380 mm thick with insulation min. Cotton wool, plastered with decorative facade plaster. Exterior walls are attached to monolithic structures using reinforcing bars welded to embedded parts of monolithic walls or columns. The internal walls of the stairwells are monolithic, made of B25 class concrete, 200 mm thick, reinforced with frames made of Ø12A400 and longitudinal Ø6A240. Monolithic columns with a section of 400x400 made of class B25 concrete, reinforcement Ø16,22A400 and Ø8A240 (clamps). Spatial frames knitted. From el. +6.820 (3rd floor) along the axes 8/A, 2 metal columns are installed, filled with B25 concrete and internal frames: 4 Ø 12A400 and clamps Ø 6A240. The use of metal columns is due to the architectural solution of the corner bay window. Bearing structures of the attic floor - combined: monolithic reinforced concrete. columns and metal columns in the alignment of the outer walls. The load-bearing structures of the coating are metal, designed in the form of a beam cage supported by monolithic beams and columns of the building frame and metal columns. All coating structures are designed from welded hot-rolled I-beams No. 24 and No. 30 and bent-welded square pipes. Spatial rigidity and stability is ensured by rigid fastening to monolithic reinforced concrete. structures of staircases, beams and columns. Roofing - roofing steel with a polymer coating. Insulation - extruded polystyrene foam foam 35 150 mm. Metal columns are load-bearing elements, therefore, after the installation and concreting of the columns, the metal surfaces must be plastered with a layer of 2 cm along the grid. Ceilings and roofing above elevation 0.000 Monolithic beamless concrete class B25 220 mm thick, reinforcement Ø12,16A400 with a pitch of 100...250 mm. Ladders. Monolithic stairs made of class B25 concrete, lined with tiles or artificial stone. Elevator shafts Monolithic of B20 class concrete 16mm thick, fittings Ø0A12 and Ø400B5. Materials Concrete grades for frost resistance and water resistance of reinforced concrete structures are adopted in accordance with SNiP 500-52-01: for foundation slabs and the outer wall of the basement - class B2003, W25, F8 concrete. for internal walls, columns - concrete class B150, W25, F4; for floors and coatings - concrete class B100, W25, F6. For reinforcing reinforced concrete structures, working reinforcement of class A100 according to GOST 400-5781 * or A82C according to STO ASChM 500-7 is used, and distribution reinforcement of class A93 according to GOST 240-5781 *. For embedded products in reinforced concrete structures, sheet steel C82 is used in accordance with GOST 235-27772 *, anchors from reinforcement of class A83 in accordance with GOST 400-5781 *.