RU2244783C1 - Method for connection of eccentrically loaded column with stepped foundation - Google Patents

Abstract

FIELD: building, particularly frame structures for civil and industrial buildings to be erected mainly on sinking territories or territories to be developed.

SUBSTANCE: method for connecting eccentrically loaded column with foundation by fixing thereof in orifice formed in foundation involves forming composite multi-stepped foundation having central, medium and outer steps and through wedge-like orifices made in each step, wherein orifices taper downwards with cone angle of 1/10 to 1/5 (5.7 - 11.3^o) and each step and lower column end are also wedge-like and have cone angles of 1/12 - 1/6 (4.8 - 9.5^o), steps are inserted one into another and wedge-like column end extends into central orifice of central foundation step; tightly installing pair of force mounting wedges in gap between wedge-like column end and foundation, wherein each mounting wedge comprises two levers pivotally connected by the first ends to change cone angle of wedge and to regulate column verticality; securing jack communicating with hydraulic pulsing pumping plant to one lever; filling gap between foundation steps and gap between wedge-like column end and foundation with solid powder material, particularly with crushed granite with particle dimensions of 5 - 10 mm; covering upper part of central orifice of central step with concrete plug of 40 - 50 mm thickness along column perimeter; arranging centering pads on concrete plug symmetrically about eccentrically loaded column; installing pair of jacks on centering pads; securing mounting device formed as split terminal including L-shaper rests pressed to column and connected one to another by means of two bars and pins with stressing nuts, wherein jack pistons cooperate with L-shaped rests from below to maintain design position of eccentrically loaded column and to solidify powder material in gap between column tip and foundation orifice wall.

EFFECT: provision of straightening column position relative foundation without connection unit damage; increased reliability of anchoring eccentrically loaded column in foundation.

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Description

The present invention relates to the construction of frames of civil and industrial buildings, built mainly on subsiding soils and undermined territories.

Monolithic and prefabricated step foundations for reinforced concrete and steel eccentrically compressed columns are known [1, p.137 ... 139, Fig.5.7]. Prefabricated columns are connected to the stepped foundation by means of a recess in the form of a glass. The recess has a bottom. Gaps of 50 ... 75 mm between the column and the walls of the glass are tightly filled with fine-grained concrete of a class not lower than B15. This seeks to ensure the solidity of the junction of the column with the foundation.

Also known is a hollow foundation filled with crushed stone [2, patent RU No. 2123091]. The regulation of its spatial position is carried out by forced injection of pulp into a cavity filled with crushed stone. We will take the well-known technical solutions for analogues.

The disadvantages of the first analogue are as follows:

- concrete filling the gaps between the column core and the foundation, especially when working in winter conditions, does not provide reliable pinching of the column in the foundation;

- when performing work in the winter and freezing water in a glass, the foundation breaks;

- it is impossible to straighten the position of the column relative to the foundation without destroying the node of their connection;

- if the quality of filling the gap between the column and the foundation is poor, all compressive force is transmitted to the bottom of the glass and the bottom can be forced through the bottom end of the eccentrically compressed column.

The disadvantage of the second analogue [2] is the need to destroy the floor in the workshop and the possibility of breaking through the pulp from under the base of the foundation.

The technical result of the invention is the provision of straightening the spatial position of the column relative to the foundation without destroying the connection node and ensuring reliable anchoring of eccentrically compressed columns in the foundation.

The technical result is realized by the fact that the eccentrically compressed column is connected to the foundation by pinching it into a hole in the foundation.

The difference is that the foundation is multi-stage, composite. It has a central, middle and outer steps with a through central wedge-shaped hole in each of the steps, tapering downward with a taper of 1/10 ... 1/5 (5.7 ... 11.3 °).

Each step and the lower end of the column are wedge-shaped and have a taper 1/12 ... 1/6 (4.8 ... 9.5 °), while the steps are nested one into the other, and the wedge-shaped end of the column is inserted into the central hole in the central foundation steps.

In the gap between the wedge-shaped end of the column and the foundation, a pair of power mounting wedges is tightly inserted, each of which contains a pair of levers pivotally connected at one end with the ability to change the angle of taper of the wedge and adjust the verticality.

At the same time, a jack is connected to one of the levers, which is in communication with the hydro-pulsating pump station, and the gaps between the steps of the foundation and the tapered end of the column and the foundation are densely filled with strong loose material, for example, granite chips with a particle size of 5 ... 10 mm.

The upper part of the central hole of the central stage along the contour of the column is closed with a concrete plug 40 ... 50 mm thick, on which centering pads are placed symmetrically with respect to the eccentrically compressed column.

A pair of jacks is installed on the centering pads, and a mounting device in the form of a collet clamp is fixed on the column, consisting of L-shaped stops, tightly pressed to the column and connected to each other by a pair of beams by means of studs with guide nuts.

The pistons of the pair of jacks interact from below with the L-shaped stops of the mounting device, ensuring restoration of the design position of the eccentrically compressed column, and compacting the bulk material in the gap between the wedge-shaped end of the column and the walls of the hole in the foundation.

Comparison of the new design of the connection unit of an eccentrically compressed column with the foundation shows the following significant differences from its analogue, namely:

- a composite foundation, multi-stage with through wedge-shaped, central holes in each of the steps, tapering downward with a taper of 2β = 1/10 ... 1/5 (5.7 ... 11.3 °);

- the bottom of the column and each of the steps are also wedge-shaped with less taper 2α = 1/12 ... 1/6 (4.8 ... 9.5 °);

- the wedge-shaped end of the column is inserted into the through wedge-shaped, central hole in the foundation and precisely fixed in it in the design position by a pair of mounting wedges that perform the functions of a conductor;

- a pair of mounting wedges ensure the installation of an eccentrically compressed column exactly vertically and allow to straighten the column position in the plan within ± (40 ... 50 mm) and in height;

- the central foundation is introduced into the next step of the multi-stage foundation with the additional possibility of straightening ± (40 ... 50 mm);

- anchoring of the column and the foundation steps in each other is achieved by densely filling the cavities around the wedge-shaped end of the column and the cavities separating the foundation steps from one another, with loose material, for example granite crumb with a particle size of 5 ... 10 mm with compaction by ramming it;

- the wedge-shaped end of an eccentrically compressed column wedges and compacts the bulk material in the gap and reliably pinches it in the foundation, and the compressive forces from the wedge-shaped end of the column are transmitted through the compressed bulk material (granite crumb) to the foundation;

- in case of uneven settlement of the foundation, a concrete plug 40 ... 50 mm thick around the column is easily destroyed and the column is jacked up without damage.

Figure 1 shows the site of the hard connection eccentrically compressed columns with the foundation; figure 2 is a view along aa (plan); figure 3 - mounting wedge; figure 4 - the installation process of the column.

The node contains an eccentrically compressed column 1 reinforced concrete or steel with a wedge-shaped end 2. The wedge-shaped end 2 has a taper of 1/12 ... 1/6 (4.8 ... 9.5 °). In Fig. 1, the foundation has three steps embedded in one another: central, middle and external. The central stage of the foundation 3 has a central hole 4 also tapered downward, and the taper of the hole 4 is greater than the taper of the lower end of the column. The taper of the through hole 4 is 2β = 1/10 ... 1/5 (5.7 ... 11.3 °).

Between the wedge-shaped end of the column 1 and the walls of the wedge-shaped through hole 4 there is a gap, tapering downward. At the top of the foundation, the gap is 75 ... 100 mm, and at the bottom of the column is 40 ... 50 mm. The wedge-shaped end 2 of the eccentrically compressed column has a length exceeding the cross section height of the eccentrically compressed column by 1.8 ... 2 times. The mentioned gap along the contour of the wedge-shaped end 2 of column 1 is filled with strong bulk material 5, for example, crushed stone from granite with a grain size of fractions 5 ... 10 mm.

The central step of the foundation 3 rests on the soil base 6 and is embedded in the middle step. The middle step of the foundation 3 is embedded in the outer step.

The top of the hole 4 along the contour of the column is sealed with a concrete plug 7.

On the concrete plug 7, centering pads 8 of the required thickness are installed, depending on the upsetting of the multi-stage foundation 3 and column 1.

To perform spatial straightening of the column 1 on the centering pads 8 installed a pair of jacks 9 symmetrically relative to the column 1.

The pistons of the jacks 9 are supported from below in the L-shaped stops 10 of the mounting device in the form of a collet 11. The L-shaped stops 10 are pressed tightly against the shaft of the column 1 by means of beams 12, studs 13 and tension nuts 14. To increase friction, the L-shaped stops 10 have a notch is similar to a notch on wedge clamps in tensile testing machines [3]. Under the action of jacks 9 force

The grip of the collet clamp with the column 1 is increased, since the jacks act on the L-shaped stops 10 with an eccentricity.

Figure 4 shows an eccentrically compressed column during installation. After lowering the eccentrically compressed column 1 with a wedge-shaped end 2 into the central hole in the foundation 3, the column 1 is temporarily fixed and fixed by means of mounting wedges 15 (Fig. 3).

Each of the mounting wedges 15 contains a pair of levers 16, pivotally connected at one end with the possibility of changing the taper angle of the mounting wedge.

In the articulation of a pair of levers, a ball hinge 17 is inserted, which engages in the holes in the levers 16, and pads 18, pivotally connecting the levers 16. A jack 19 is attached to one of the levers, connected by a hose 20 to a hydro-pulsating pump station 21 operating in a cyclic mode [3, p. 268 ... 271], [4, p. 473].

The sequence of construction of the foundation and the connection of the column with the foundation.

1. Make a geodetic breakdown, for example, using laser levels.

2. In accordance with the axes of the building, the reinforcing frame of the outer step of the foundation 3 and the steel formwork, consisting of the outer shell and the conical hollow core, are precisely installed and fixed relative to each other.

3. Four aiming flies, for example, of wire, are fixed on the formwork. The position of the formwork is adjusted so that the beam from each of the two levels passes over the edge of the flies. It is necessary to use two laser levels simultaneously, sending two mutually perpendicular beams.

4. Concrete the outer step of the foundation, supplying concrete, for example, with a concrete pump and compacting concrete with vibration.

5. After the concrete has set, the outer shell of the formwork is dismantled and the cone-shaped core is removed.

6. Lubricate the inner surface of the outer step of the foundation with an emulsion that prevents adhesion, and by installing reinforcing cages of the middle step and the middle void forming agent on the conductor, the middle step of the foundation 3 is concreted. Then, the central step of the foundation 3 is concreted in the same manner. steps of the foundation, the accuracy of the central hole is increased.

7. Fill the through wedge-shaped hole in the central stage of the foundation with bulk material to the design elevation and compact it with a rammer.

8. The eccentrically compressed column 1 is lowered by a crane, guiding its wedge-shaped end 2 to the center of the hole until it stops in bulk material.

9. Wedge the wedge-shaped end 2 in the foundation 3 with two mounting wedges 15 on both sides of the eccentrically compressed column 1 and, controlling the oil supply from the hydropulsing pump station 21 through the hose 20 with wedges 15, install the eccentrically compressed column 1 exactly vertically and exactly at the intersection of the center axes of the building in plan.

The accuracy of the installation of an eccentrically compressed column is controlled using laser levels and two targets with a coordinate grid glued to the surface of the column. The sinuses arising from all four sides of the wedge-shaped end of the column are densely filled with loose material, for example granite crumbs with a particle size of 5 ... 10 mm. Compaction of bulk material is carried out by ramming or jacking. Bulk material is not brought to the top of the foundation 3 by 40 ... 50 mm. Then, along the contour of the column, a concrete plug with a thickness of t = 40 ... 50 mm is flush with the upper face of the foundation 3.

The method of straightening the spatial position of the column in relation to the foundation.

In the event of uneven settlement of the soil base and the corresponding uneven settlement of the foundations and columns, restoration of the design position of the columns is achieved as follows:

- a symmetric pair of centering pads 8 of the required thickness is laid on the concrete plug 7 depending on the settlement of the foundation and the column;

- on the centering pads 8 install a pair of jacks 9 cyclic operation [3, p. 369], [4, p. 473];

- on the rod of an eccentrically compressed column 1 install L-shaped stops 10 of the mounting device 11 in the form of a collet clamp and tighten a pair of beams 12, a pair of studs 13 with tension nuts 14;

- fix the mounting device 11 on the shaft of the column 1 at the required height, abutting the pistons of the jacks 9 in the L-shaped stops 10 from the bottom;

- turn on the pulsating pump station 21, creating pressure and pulsation of oil in the pipelines of the hydraulic system and informing this not only the power, but also the cyclic action of the pair of jacks 9;

- force and cyclic effects of a pair of jacks 9 gradually increase and, finally, overcome the support reaction of an eccentrically compressed column 1 and the pinched action of granular material (crushed granite) in the gaps around the wedge-shaped end of the column, the concrete plug around the column core is crushed and pressed into the gap;

- the process of returning the eccentrically compressed column 1 to the design position is controlled by laser levels and targets with a coordinate grid glued to the surface of the column (the design point on the target is pre-selected);

- cycles of jacking of an eccentrically compressed column 1 are repeated as many times as necessary with the appropriate addition of granular material (crushed granite);

- after full restoration of the design position of the eccentrically compressed column 1, the concrete plug 7 is restored along its contour.

The following economic effect occurred:

- provided mechanized straightening of the spatial position of the column relative to the foundation with great accuracy and the lowest labor costs;

- for small precipitations and horizontal deviations of the core of the column 1 for straightening, use the gaps between the tapered end of the column and the central step of the foundation, and for large precipitations, additionally use the gaps between the steps of the foundation 3;

- if it is necessary to remove bulk material from the gap, use a hydraulic monitor and wash the crushed stone with a stream of water under pressure;

- increased reliability of anchoring the column while expanding the limits of movement of the column both vertically and horizontally;

- additional mounting devices have been developed: mounting wedge and collet clamp, facilitating the time-consuming installation process and especially straightening the position of the column during the operation of the building.

Literature

1. Kudzis A.P. Reinforced concrete and stone structures. Textbook for builds. specialist. universities. In 2 parts. Part 2. Designs of industrial and civil buildings and structures. - M .: Higher. school, 1989 .-- 264 p.

2. Nezhdanov K.K., Nezhdanov A.K., Kuzina V.N. RF patent №2123091, 12.10.1998.

3. Serensen S.V., Garf M.E., Kozlov L.A. Fatigue Testing Machine / Ed. S.V. Serensen. Mashgiz. M. 1957.-404 p.

4. Metal structures. In 3 t. T. 3. Steel structures, structures of aluminum alloys. Reconstruction, inspection, strengthening and testing of structures of buildings and structures. (Designer Handbook) / Under the general. ed. V.V. Kuznetsov (Central Scientific Research Instituteprojectstalkonstruktsiya them.N.P. Melnikov) - M.: Izv. In DIA, 1999.-528 p.

Claims (1)

A junction of an eccentrically compressed column with a foundation by pinching it into a hole in the foundation, characterized in that the foundation is made of a multi-stage composite of the central, middle and external steps with through central, wedge-shaped openings in each of the steps, tapering downwards with a taper

...

(5.7 ... 11.3 ⁰ ), and each of the steps and the lower end of the column are wedge-shaped and have a taper

...

(4.8 ... 9.5 ⁰ ), while the steps are nested one into the other, and the wedge-shaped end of the column is inserted into the central hole of the central stage of the foundation, and in the gap between the wedge-shaped end of the column and the foundation a pair of power mounting wedges are tightly inserted, each of which contains a pair of levers pivotally connected at one end with the possibility of changing the angle of the taper of the wedge and adjusting the verticality, while on one of the levers a jack is connected that communicates with the hydro-pulsating pump station, and the gaps between the steps of the foundation and the columned end of the column and the foundation are densely filled with strong loose material, for example, granite chips with a particle size of 5 ... 10 mm, and the upper part of the central hole of the central step along the column contour is closed with a concrete plug 40 ... 50 mm thick, on which centering pads are placed symmetrically relative to the eccentrically compressed column on which a pair of jacks are installed, and a mounting device in the form of a collet clamp is fixed on the column, consisting of L-shaped stops, tightly pressed to the column and connected to a pair of beams with another by means of studs with tensioning nuts, and the pistons of the pair of jacks interact from below with the L-stops of the mounting device, ensuring restoration of the design position of the eccentrically compressed column and compacting the bulk material in the gap between the tip of the column and the walls of the hole in the foundation.

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