RU116516U1 - STRENGTHENING BASE STRENGTH - Google Patents

Abstract

1. The structure of foundation reinforcement, including the grillage of the existing foundation, a monolithic reinforced concrete slab with holes, existing piles, screw jacks, characterized in that a new monolithic reinforced concrete slab (shallow foundation) is arranged under the grillage of the existing foundation, and between them (the grillage of the existing foundation and new monolithic reinforced concrete slab), screw jacks and, if necessary, vertical posts are installed. ! 2. The structure of the foundation reinforcement according to claim 1, characterized in that screw jacks are installed on the surface of the new monolithic reinforced concrete slab, consisting of thrust sheets, expansion bolts, thrust bushings, nuts, washers and centering balls. ! 3. The structure of the foundation reinforcement according to claim 1, characterized in that, if it is necessary to install vertical struts on the surface of a new monolithic reinforced concrete slab, screw jacks are mounted on top of the vertical struts. ! 4. The structure of reinforcement of the foundation according to claim 1, characterized in that the degree of inclusion in the operation of the new monolithic reinforced concrete foundation of shallow foundation is controlled by the reinforcement in screw jacks, and the reliability of the reinforcement is achieved by observing the process of stabilization of the active wedging efforts.

Description

The foundation reinforcement design relates to construction, in particular to foundation engineering, and is intended for use: in the repair of buildings and structures that have received uneven deformations, or during reconstruction with an increase in the loads on the foundations.

Depending on the type of building foundations, the characteristics of the foundation soils, design features and current efforts, various reinforcement methods are provided. Strengthening pile foundations by changing the characteristics of soils by cementation, silicatization, etc. is significantly costly and does not guarantee a proper reinforcement result. In addition, it is not always possible to objectively assess the state of soils after reinforcement, as well as to calculate the deformation of loaded foundations over time, i.e. evaluate the reliability of the amplification performed. Other methods of reinforcement (for example, finishing piles, fixing soils) are not always really applicable in the conditions of existing development and cannot provide the required operational parameters of reinforced foundations.

It is known that increasing the bearing capacity of foundations and reducing deformations can be achieved by including the grillage in collaboration with piles and providing partial transfer of loads to the base through the sole of the grillage. There are recommendations for calculating the pile foundation together with the grillage (SP 24.13330.2011 “Pile foundations”). The regulatory documents (SP 50-102-2003 “Design and construction of pile foundations”) provide for the perception of a grill 15% of the total bearing capacity of combined pile-plate foundations (KSP). This value is variable and to a large extent depends on the characteristics of the soils under the sole of the grillage, the quality of the preparation of the foundation, the technology for laying foundations, etc. Full-scale tests carried out at different sites indicate that the proportion of the load perceived by the grillage in the composition of the PCB can be 18 ... 21% [See Krasnoshchekov Yu.V. - Joint work of piles with a low grillage // Vestnik SibADI, issue 5. - Omsk, 2007. - p. 65-69], 20 ... 40% [See Chunyuk D.Yu. Calculation of combined pile-slab foundations: Diss. Cand. tech. sciences. Moscow. 2002. - p.126], 7 ... 45% [Glushkov I.V. Choice of a method for calculating massive pile foundations // Proceedings of the international scientific and practical seminar "Actual problems of design and construction in urban areas." - Perm, 2005 .-- v.2. - p. 18-21].

- The main problem of combined pile-plate foundations is to ensure the reliability of the inclusion of grillage. The proper degree of inclusion of the grillage in the work of the foundation can actually be ensured due to its controlled active inclusion.

A device is known for reinforcing the foundation, consisting of reinforced concrete frames and an additional foundation made of prefabricated slabs (Malganov A.I., Plevkov BC, Polishchuk A.I. "Reinforcement of reinforced concrete and stone structures of buildings and structures. Tomsk, 1988, sheet 66 )

The disadvantages of such a device are:

- lack of preliminary soil compression when installing reinforcement frames;

- reduction of the useful area of premises when installing reinforced concrete frames;

- high material consumption of the amplification device.

A device is known in the method for reinforcing foundations, consisting of additional foundations and an electro-hydraulic jack system, which consists in arranging jack openings, removing backfill soils, installing an electro-hydraulic system, jacking the building, and caulking the formed gap (see Lobov O.I., Gapeev V.I., Zotov V.D., Bolotov Yu.K., Zotov M.V .. Lifting and leveling of emergency buildings // Industrial and civil construction, issue 2/1999. - Moscow, 1999. - p.15 -16).

The disadvantages of this device are:

- short-term unloading of the foundations, as a result of which the soils under the influence of additional pressure do not fully realize deformations, which leads to their further compaction and settlement;

- monolithic concrete used for caulking gaps, shrinks, resulting in gaps and redistribution of forces in the foundations and reinforcement structures;

- To implement the amplification, expensive special equipment is required (pump station, jacks, hoses and high pressure pipelines).

The closest analogue of the proposed utility model is the foundation reinforcement design RU108054, U1, 03/18/2011. This foundation reinforcement design includes a monolithic reinforced concrete slab with holes in which piles are arranged. The monolithic reinforced concrete slab is equipped with embedded parts and is located in the lower part of the foundation, and its ends are brought under the base of the foundation, while the piles are made injection, and the reinforcing cages of injection piles are welded with the embedded parts of the monolithic reinforced concrete slab. Monolithic reinforced concrete beams were used as a monolithic reinforced concrete slab.

For reasons that impede the achievement of the technical result indicated below, when using the known device, the fact that the known device is absent:

- the ability to regulate efforts when performing amplification;

- joint work of the plate with the base when the plate is torn off the ground

- the impossibility of determining the bearing capacity of reinforcing piles in certain soils;

When using the known device there is a difficulty in implementing the amplification method, due to the significant costs when performing injection piles in cramped conditions; the eccentricity of the load transfer to the injection piles, leads to the work of piles for eccentric compression.

The challenges in creating a utility model are:

- development of a device for strengthening pile foundations,

- ensuring the guaranteed transfer of part of the effort to the foundation soil through the sole of the grillage and the transition to a combined pile-slab foundation,

- the creation of a relatively simple, relatively cheap and feasible in building conditions devices.

The combination of new essential features - a new monolithic reinforced concrete slab, arranged under the grillage of the existing foundation, screw jacks, if necessary, vertical struts together with well-known features make it possible to obtain the planned technical result and create a technical solution that surpasses the closest analogue in technical result.

The technical result that allows to solve the problem is:

- increase the bearing capacity of the pile foundation and reduce its further deformations;

- guaranteed support for the joint operation of the existing pile foundation with a reinforcement structure (a new monolithic reinforced concrete shallow plate and screw jacks).

- unloading existing foundations to specified parameters,

- the possibility of regulating the efforts on the foundations during the life of the building.

The specified technical result is achieved by the fact that in the “Construction of reinforcing the foundation”, including the grillage of the existing foundation, a monolithic reinforced concrete slab with holes, existing piles, screw jacks, characterized in that under the grillage of the existing foundation they arrange a new monolithic reinforced concrete slab (shallow foundation), and between them (a grillage of the existing foundation and a new plate) screw jacks and, if necessary, vertical racks are installed. Screw jacks are installed on the surface of the new monolithic reinforced concrete slab, consisting of thrust sheets, spacer bolts, thrust bushings, nuts, washers and centering balls. If it is necessary to install vertical posts on the surface of a new monolithic reinforced concrete slab, screw jacks are mounted on top of the vertical posts. The degree of inclusion in the work of a new monolithic reinforced concrete foundation of shallow laying is controlled by the gain in screw jacks, and the reliability of the gain is achieved by observing the process of stabilization of the forces of active wedging.

Like the closest analogue, the claimed foundation reinforcement design includes a monolithic reinforced concrete slab (shallow foundation). A monolithic reinforced concrete slab is concreted in an additional pit arranged below the sole of the existing grillage. Proppants (screw jacks) are installed between the existing grillage and the new monolithic reinforced concrete slab or, if necessary, on vertical racks. As the foundation is loaded, part of the efforts acting on the foundation perceives a new foundation of shallow laying. Thus, the active elements are reinforced in collaboration with the existing foundation structures and the transition from the pile foundation to the combined pile-plate foundation. The degree of inclusion in the work of an additional foundation of shallow laying is controlled by the force in the screw jacks, and the reliability of the gain is achieved by observing the process of stabilization of the forces of active wedging.

The implementation of the reinforcement design in the claimed utility model allows for reinforcing pile foundations using additionally arranged shallow foundations (new monolithic reinforced concrete slabs), proppants (screw jacks) and, if necessary, vertical racks.

The device is represented by drawings.

Figure 1 shows the construction of reinforcing the foundation (without vertical struts).

Figure 2 presents the construction of reinforcing the foundation (with uprights).

Figure 3 - presents a General view of the screw jack (proppant) for the elements.

Figure 4 - presents a General view of a screw jack with reinforcement.

Figure 5 - presents a vertical rack.

The positions in the figures indicate:

1 - grillage of the existing foundation,

2 - a new monolithic reinforced concrete slab of shallow laying,

3 - holes

4 - existing piles,

5 - screw jacks,

6 - upper thrust sheet,

7 - lower thrust sheet,

8 - spacer bolts,

9 - thrust bushings,

10 - nuts

11 - washers

12 - centering balls.

13 - vertical racks, installed if necessary.

The inventive device includes a grillage of the existing foundation 1, a new monolithic reinforced concrete shallow plate 2 with holes 3 for passing existing piles 4, screw jacks (proppants) 5, consisting of upper 6 and lower 7 thrust sheets, spacer bolts 8, thrust bushings 9 , nuts 10, washers 11, centering balls 12, vertical posts 13 (installed if necessary).

The inventive device allows to obtain a technical result, which consists in

- increase the bearing capacity of the pile foundation and reduce its further deformations;

- guaranteed support for the joint operation of the existing pile foundation with a reinforcement structure (a new monolithic reinforced concrete shallow plate and screw jacks).

- unloading existing foundations to specified parameters,

- the possibility of regulating the efforts on the foundations during the life of the building.

The inventive device is used as follows. Under the sole of the grillage of the existing foundation 1 dig a pit. The minimum depth of the pit is determined from the conditions of convenience of work on strengthening. At the bottom of the dug pit, a new monolithic reinforced concrete slab (shallow foundation) 2 is concreted, with holes 3 for passing existing piles 4. The dimensions of the new monolithic shallow concrete slab 2 are assigned based on the value of the additional load that must be taken from the grillage of the existing foundation 1. Screw jacks 5 are installed on a new monolithic reinforced concrete slab of small laying 2. If necessary, for the convenience of performing work on reinforcement on a new monolithic reinforced concrete a small shallow laying plate is pre-mounted with vertical posts 13, on top of which screw jacks are installed 5. Screw jack 5 consists of upper 6 and bottom 7 thrust sheets, spacer bolts 8, thrust bushings 9, nuts 10, washers 11, centering balls 12. Installation shallow new monolithic reinforced concrete slabs are made on leveling gravel from a cement-sand mortar.

By unscrewing the spacer bolts 8 in the screw jacks 5, an axial wedging force is created, controlled by a torque wrench. The size of the wedging force depends on the required value of unloading piles and the amount of force transmitted to the new monolithic reinforced concrete slab.

After creating the initial voltage, the object is reconstructed, accompanied by an increase in the loads on the foundations. In this case, the observation of the magnitude of the efforts in the wedging bolts is established. After some time, under the monolithic reinforced concrete slab of small laying 2, the soil is compressed, which leads to a decrease in the wedging force in the screw jack 5. As the sediments of the base soils change and the forces in the proppants stabilize, they additionally wedge the bolts with a torque wrench with the required axial force (torque moment). The regulatory process is completed upon reaching the calculated stabilization of efforts.

Thus, there is an active and controlled inclusion of a new monolithic shallow concrete slab 2 in joint work with piles 4 and a grillage of the existing foundation 1, reinforcement of the pile foundation by transferring the required part of the effort to a new monolithic reinforced concrete slab 2 and the transition to a combined pile slab foundation. The degree of inclusion in the work of a monolithic reinforced concrete slab of small laying 2 is controlled by the force in the screw jack 8 using torque wrenches, and the reliability of the gain is achieved by prolonged monitoring of the process of attenuation of the sediment and stabilization of the forces of active wedging. When implementing reinforcement, it is possible to regulate efforts during the life of the building and to unload foundation elements with certain parameters of the stress-strain state. After reaching the conditions of stabilization of efforts in the proppant bolts of the reinforcement structure, the screw jack is monolithic with concrete.

The inventive design is industrially applicable and can be repeatedly implemented to achieve the specified technical result. The foundation reinforcement design has been tested in practice by reinforcing several reconstructed facilities in Omsk and the Omsk Region.

Claims (4)

1. The foundation reinforcement design, including a grillage of the existing foundation, a monolithic reinforced concrete slab with holes, existing piles, screw jacks, characterized in that a new monolithic reinforced concrete slab (shallow foundation) is arranged under the grillage of the existing foundation, and between them (grillage of the existing foundation and new monolithic reinforced concrete slab) installed screw jacks and, if necessary, vertical racks. 2. The foundation reinforcement design according to claim 1, characterized in that on the surface of the new monolithic reinforced concrete slab screw jacks are installed, consisting of thrust sheets, spacer bolts, thrust bushings, nuts, washers and centering balls. 3. The construction of reinforcing the foundation according to claim 1, characterized in that if it is necessary to install vertical posts on the surface of a new monolithic reinforced concrete slab screw jacks are mounted on top of the vertical posts. 4. The foundation reinforcement design according to claim 1, characterized in that the degree of inclusion in the work of a new monolithic reinforced concrete foundation of shallow laying is controlled by the gain in the screw jacks, and the reliability of the gain is achieved by observing the stabilization process of the active wedging forces.