EP2251503A2

EP2251503A2 - Method for replacing a loadbearing wall

Info

Publication number: EP2251503A2
Application number: EP10004866A
Authority: EP
Inventors: Arvu Mägi; Joel Lipson
Original assignee: Amhold AS
Current assignee: Amhold AS
Priority date: 2009-05-08
Filing date: 2010-05-07
Publication date: 2010-11-17
Anticipated expiration: 2030-05-07
Also published as: EP2251503A3; EP2251503B1; EE00888U1

Abstract

The presented solution concerns the replacement of a loadbearing wall (1) on infirm soil. For this a recess (2) is created on both sides of the loadbearing wall (1), piles (3) are driven at the bottom and the recess is supported with a temporary supporting wall (6). On-pile foundation (8) is built on top of the piles (3). Cross-beams (12) are installed under the loadbearing columns (11) supporting the loadbearing wall (1), and the recess (2) is backfilled and compacted. Temporary supports (18) are installed on both sides of the loadbearing wall (1) on all floors, and openings are cut into the loadbearing wall (1) for loadbearing columns (11), ad the loadbearing columns (11) are installed to cross-beams (12). Then a hole is cut for the loadbearing beams (23) into the loadbearing wall (1) for a half of its thickness under the ceiling structure (17), and first one loadbearing beam (23) and then the second loadbearing beam (23) is mounted to the loadbearing columns (11), the space between the loadbearing beams (23) is filled with a fire-retardant and sound insulating material (26) and then the section (27) of the loadbearing wall under the loadbearing beams (23) is demolished. Then the previous installation of loadbearing columns and the loadbearing beam is repeated in all the spaces between the columns until the whole column-beam system is complete.

Description

Technical field

The invention belongs in the construction field, more specifically a method for replacing a loadbearing wall on infirm soil.

Prior art

The problem underlying this invention is that often it is necessary to replace existing loadbearing walls with a beam-column system, such as to create a more spacious room in the course of reconstruction works. At this the foundation under the loadbearing walls has insufficient loadbearing capacity or depth in order to apply the concentrated extra load received from the column. The demolition of a loadbearing wall and building a beam-column bearing system often involves substantial working volumes, which do not justify the effect of more spacious premises. Often it is also necessary to dredge the floor beneath the level of the existing pad footing with the purpose of increasing the height of the existing plinth/basement floor.
In the patent application "Building structure" ( JP2002227303 , Takenaka Komuten Co, published on 14.08.2002) a solution for creating a more spacious room has been presented, stating a structure, where a steel supporting framework contains a steel framework column and cross-beams, reinforced concrete walls, while the cross-beam of the footing is positioned only along the lower part of the wall, the foundation is positioned in the bottom part of the steel framework column. Walls are located at suitable distances from each other in the crosswise direction and instead of installing the beam between the upper parts of the numerous adjacent walls, the bottom section of the lower part of the wall is connected to the cross-beam of the footing with a rigid connection.
From the technical nature, a solution presented in the patent application "Building structure" ( JP52705629 , Kajima Corp., published on 16.12.1982) is the closest to this invention. The underground wall of the building is the penetrating part and it is made from reinforced concrete. The ground wall of the building is connected to the underground wall by integration, in order to provide the ground part with higher resistance to the horizontal force that acts on the ground wall from the underground wall. In order to connect the underground wall with the ground wall and form a whole, the upper part of the steel reinforcement is used, which is in the H shape and has the bottom section positioned in the connection part of the underground wall, containing steel tubes and steel piles, and the steel reinforcement is recessed into a column of the ground wall. The steel reinforcement is fitted with a projecting double-end bolt and the underground cross-beam is intended for the upper part of the underground wall.
The known solutions do not solve the problem underlying the given invention.

Description of the invention

The method for the replacement of the loadbearing wall comprises the stages: on both sides of the loadbearing wall a recess is created for the loadbearing wall, piles are driven at the bottom of the recess down to a bearing soil layer and the recess is supported by means of a temporary supporting wall. On-pile foundation is built on top of the driven piles, supporting the cross-beams that will be under the loadbearing columns to the foundation, after which the recess is backfilled and compacted and the temporary supporting walls removed. Then the temporary supports that support the loadbearing structures of the ceiling of all floors and are supported on the on-pile foundation are installed on both sides of the loadbearing wall, openings are cut in the loadbearing wall for the loadbearing columns and the loadbearing columns are installed on the cross-beams. Then an opening is cut in the loadbearing wall for the loadbearing beam and one loadbearing beam is mounted to the loadbearing columns on one side of the loadbearing wall and then the second loadbearing beam is mounted to the other side of the loadbearing wall, filling the gap between the loadbearing beams with a fire retardant and sound insulating material, and demolishing the section of the loadbearing wall under the loadbearing beam. The installation of loadbearing columns and beams is repeated in the next gaps between the columns as provided above, until the column-beam loadbearing system is complete and building of the rough floor can be finished.

List of figures

The figure presents the plan of a building, where the method for loadbearing wall replacement is applied.

Exemplary embodiment of the invention

Next to loadbearing wall 1, in parallel with the wall, recess 2 is created, at the bottom of which micro piles 3 are driven until reaching a loadbearing soil layer 4. Recess 2 is created with a width that makes it possible for the machine that drives micro piles 3 to move and work. Depending on the geotechnical characteristics of subsoil 5, recess 2 is supported with a temporary supporting wall 6. If the level of surface water 7 reaches over the bottom of recess 2, surface water is removed from recess 2 during construction works.
After micro piles 3 are driven in, the on-pile foundation 8 from reinforced concrete is built on the piles. The on-pile foundation 8 from reinforced concrete is reinforced near the upper and lower level by means of steel fittings 9. Steel fittings 9 are pre-tensioned. Recess 2, micro piles 3 and on-pile foundation 8 are initially created on one side of loadbearing wall 1 and then to the other side of loadbearing wall 1. Recess 2 is created at such distance from loadbearing wall 1 that the stability of foundation 10 of the loadbearing wall would be ensured, and taking into account supporting wall 6 of recess 2.
Cross-beams 12 that are rested on on-pile foundation 8, are installed under loadbearing columns 11 that support loadbearing wall 1. Cross-beams 12 are installed beneath the lower level 14 of the rough floor 13.
After this, recess 2 is backfilled and compacted with mineral soil to compacting degree 1.00. The temporary support walls 6 of recess 2 are removed. An elastic layer 15 is installed between cross-beams 12 and the lower level 14 of the rough floor 13 in order to compensate various deformations in rough floor 13 and cross-beams 12 as a result of moisture and temperature fluctuations. During the construction of rough floor 13, a temporary opening 16 with the width of cross-beams 12 is left in rough floor 13 for the installation of load bearing columns 11.
Then temporary supports 18 that will receive the load of the loadbearing structure 17 of the ceiling are installed on both sides of load bearing wall 1 on all the floors, supporting the load bearing structure 17 of the ceiling and resting on on-pile foundation 8.
After the installation of temporary supports 18, vertical openings are cut into load bearing wall 1 for two adjacent load bearing columns 11 and the columns are installed on cross-beams 12. Loadbearing columns 11 are installed on cross-beams 12 by means of load-resistant anchor bolts 19. Load-resistant anchor bolts 19 are supplied with pressure nuts 20 for adjusting the height of load bearing columns 11.
Loadbearing columns 11 are produced from steel tube jacket 21 and concrete core 22. With the interaction between concrete core 22 and steel tube jacket 21, i.e. load bearing column 11, the load bearing column 11 will achieve the optimum load stability and fire resistance.
Then a hole is cut for loadbearing beam 23 into load bearing wall 1, for a half of its thickness, under the loadbearing structure 17 of the ceiling, and one loadbearing beam 23 is mounted to loadbearing columns 11. After mounting the first loadbearing beam 23, the gap between load bearing beam 23 and the load bearing structure 17 of the ceiling is closed with steel wedges 24, which will provide the load bearing beam 23 with the initial tension to support loadbearing wall 1 and the load bearing structure 17 of the ceiling. After wedging the first loadbearing beam 23, the space between the loadbearing structure 17 and load bearing beam 23 is filled with expanding assembly concrete 25 by gunning.
Then the method for the installation of load bearing beam 23 is repeated on the other side of load bearing wall 1. Prior to the installation of the second load bearing beam 23 on the other side of load bearing wall 1, the gap between load bearing beams 23 is filled with fire resistant and sound insulating material 26, such as with dense rock wool. Then the load bearing wall section 27 under load bearing beams 23 is demolished.
Then the whole method for the installation of loadbearing columns 11 and load bearing beams 23 is repeated in the next space between the columns. After completing the whole column-beam system, load bearing beams 23 are covered with a fire retardant and sound insulating material 26, such as dense rock wool boards or fire resistant gypsum boards, and the temporary supports 18 are removed.
Depending on the possible subsiding of piles 3, on-pile foundation 8 and cross-beam 12 as a result of the compacting of load bearing soil 4 and subsoil 5 and reduced tension in load bearing columns 11, loadbearing columns 11 and load bearing beam 23 are provided with extra tension by means of load-resistant bolts 19 and pressure nuts 20 in order to prevent deformations in loadbearing wall 1 and the load bearing structure 17 of the ceiling. When the subsiding of piles 3, on-pile foundation 8 and cross-beam 12 has ended, the gap between loadbearing column 11 and cross-beam 12 is cast with prestressed concrete 28, and rough floor 13 is completed. Prior to the finishing of load bearing columns 11 and loadbearing beam 23, loadbearing columns are covered with fire resistant mixture 29, which will ensure the steel tube jacket 21 and thereby also load bearing column 11 with optimum fire resistance in interaction with concrete core 22.

Claims

Method for replacing a loadbearing wall, executed in a building that comprises a loadbearing wall, loadbearing columns supporting the loadbearing wall, foundation of the loadbearing wall, steel tubes and steel piles, comprising of the stages: cross-beams are installed in the foundation of the loadbearing wall, under the loadbearing columns that support the loadbearing wall, characterized in that
a recess (2) is created next to the loadbearing wall (1), piles (3) are driven at the bottom of the recess until a loadbearing layer (4), and the recess (2) is supported with a temporary supporting wall (6);
on-pile foundation (8) is built on top of the driven piles (3), it is reinforced with steel reinforcement (9) and the steel reinforcement (9) is pre-tensioned;
the recess (2), piles (3) and on-pile foundation (8) are created initially on one side of the loadbearing wall (1) and then on the other side of the loadbearing wall (1);
the cross-beams (12) installed under the loadbearing columns (11) that support the loadbearing wall (1) are rested on the on-pile foundation (8), whereat the cross-beams (12) are installed below the lower surface (14) of the rough floor (13);
the recess (2) is backfilled and compacted, and the temporary supporting walls (6) of the recess (2) are removed;
an elastic layer (15) is installed between the cross-beams (12) and the lower surface (14) of the rough floor;
the temporary supports (18) that receive the load of the structures (17) of the ceilings of the floors and rest on the on-pile foundation (8) are installed;
vertical openings are cut into the loadbearing wall (1) for two loadbearing columns (11) that are installed on cross-beams (12) by means of anchor bolts (19), while the anchor bolts are supplied with pressure nuts (20) that adjust the height of the loadbearing column (11);
openings are cut for the loadbearing beams (23) into the loadbearing wall (1) by a half of its thickness, under the ceiling structure (17), and one of the loadbearing beams (23) is mounted to the loadbearing columns (11), and the gap between the first loadbearing beam (23) and the ceiling structures (17) is closed by wedging with steel wedges (24), and the gap is filled with expanding assembly concrete (25);
the second loadbearing beam (23) is installed to the other side of the loadbearing wall (1), whereas the space between the loadbearing beams (23) is filled with a fire retardant and sound insulating material (26) and the section of the loadbearing wall (27) under the loadbearing beams (23) is demolished prior to the installation of the second loadbearing beam (23);
then the previous mounting of loadbearing columns (11) and loadbearing beams (23) is repeated in the following spaces between columns;
when the whole column-beam system is complete, the loadbearing beams (23) are covered with a fire retardant and sound insulating material (26) and the temporary supports (18) are removed;
loadbearing columns (11) and the loadbearing beam (23) is provided with extra tension by means of bolts (19) and pressure nuts (20);
when the subsiding of piles (3), on-pile foundation (8) and cross-beam has ended, the gap between the loadbearing column (11) and cross-beam (12) is cast with prestressed concrete (28) and the rough floor (13) is finished.
Method according to claim 1, characterized in that the recess (2) is created at such distance from the loadbearing wall (1) that the stability of the loadbearing wall is ensured, and the recess (2) is created with such width that it would be possible for machines to move and work in the recess.
Method according to claim 1, characterized in that the backfill of the recess is compacted with mineral soil to compacting degree 1.00.
Method according to claim 1, characterized in that the loadbearing columns (11) are produced from a steel tube jacket (21) and a concrete core (22).
Method according to claim 1, characterized in that rock wool and fire resistant gypsum are used as the fire retardant and sound insulating material (26).
Method according to claim 1, characterized in that prior to the finishing of the loadbearing columns (11) and loadbearing beams (23), the loadbearing columns (11) are coated with a fire-retardant mixture (29).