NO344767B1 - Reinforcement chair and a method for installation of a reinforcement chair for concrete in an insulation building block system. - Google Patents

Description

TECHNICAL FIELD OF INVENTION

The invention relates to a chair to be used as a support for reinforcement in an insulated building block wall structure and a method for installing reinforcement chairs for concrete in an insulating building block system where building blocks are stacked height-wise and side-wise, and where the chair allows for installation of the reinforcement elements between the building blocks before stacking the next shift of elements.

BACKGROUND FOR THE INVENTION

In many cases, there is a need for extra reinforcement in walls of a building block system. In walls built up by building block system, normally a center-center distance in vertical direction of about 600 mm is sufficient. In cases where extra reinforcement is required, a center-center distance in vertical direction of about 300 mm is required. Such heavy loads requiring additional reinforcement may occur, especially when the wall is heavy loaded with back-filled masses, filled at the exterior side of the wall, in general defined by lateral loads the wall has to withstand from an earth pressure.

State of the art is reflected in building blocks where main reinforcement elements of elongated reinforcement bars are lowered vertically down from above and down in the building block shift and where the extra reinforcement elements are inserted/threaded from the side if and when extra reinforcement elements are required due to heavy load on the wall of building blocks, after installing the next shift of building blocks.

From NO 333321B1 are known a building element for use as a form element and isolation element for the construction of foundation walls, walls, etc. comprising of at least two vertical standing sidewalls connected with a number of fixed steps, where the steps also are suited for placing reinforcement elements in horizontal direction.

From US 5566 521A are known a concrete form mould unit formed of a lightweight, insulative material defined of at least two rows of vertical core spaces, offset from each other. Concrete and reinforcing rods fill the core spaces, defining post structures. The top of the form mould unit is troughed and is filled with horizontal reinforcing rods and concrete. The form mould units are laid in courses and stacked as required to build walls, with aligned vertical cores and horizontal troughs. Each course is filled with concrete before the next course is added.

US 2007004423 A1 describes a rebar spacer for supporting reinforcing bars within a form for a concrete wall comprising transverse form ties including a flat body of non-metallic material having at least one aperture disposed in the body being configured to receive elongated reinforcing bars to substantially fix the reinforcing bar with respect to the form tie. Openings in the body allow liquid concrete to flow through the body so that concrete filling is not prevented and a mechanical interconnection with the concrete is achieved. The openings for placement and support have lips extending inwardly on each side of the opening and the distance between the lips of the opening is less than the diameter of the reinforcing bar. The rebar must thus be pressed down into the aperture, and the lips form a press fit, which holds the rebar in place in the aperture. Such lips also allows the spacer to support reinforcing bars inserted into the spacer from below.

US 2004099785 A1 shows a device and a method for suspending and positioning structural reinforcement elements, such as rebar, in a concrete structure. Each rebar support comprises a plurality of rebar support arms supporting one or more pieces of rebar in a desired orientation.

WO 2008131166 A1 a rebar support assembly utilized in structural construction beams. The assembly may include a frame having chair portion, a cage portion, an intermediate portion, and/or a header portion. Each portion may include one or more rebar receptacles designed to support a segment of reinforcement bar in a predetermined location and orientation. The receptacles may be configured to orient the rebar in a generally horizontal and/or a generally vertical position. The assembly may be configured as a unitary structure, or may be modular to customize the rebar support for a job site. In use, the assembly is positioned on the supporting surface of the concrete pour area and rebar segments are coupled to the receptacles. Concrete is then poured over/around the assembly.US 6308484 B1 shows a support device for interlocking two parallel wall panels. The wall panels typically of polystyrene and the support device comprising clips for holding reinforcing bars in place.

US 2004045238 A1 shows a system for constructing insulated concrete structures comprising panels placed horizontally in an opposing and parallel relation being kept and restrained spaced-apart by means of spreaders. The spreaders comprising opposing flanges connected by horizontal members. The horizontal members comprising recesses to accommodate reinforcement bars.

CN 200732631 U shows a building element comprising a hollow insulation block comprising two wall plates and three ribs between the wall plates distributed at both ends of the wall ends and in the middle of the wall plates, forming two vertical cavities form moulding in the block. The building element further comprises support frames of four support bars, where two and two support bars are connected at the top with two horizontal and mutually parallel connecting rods at the bottom with substantially horizontal support rods with reverse V-shaped central handle and two connecting elements diagonal between the vertical support bars. The support frames being arranged in the vertical cavities of the block. Rebar can then be placed in the support frame.

Installing reinforcement elements by inserting them from the side are both inconvenient and time consuming, and laborious and proper joining of lengths of reinforcement elements are difficult. When working at construction sites, Health, Safety and Environment requirements are of great important, through e.g. enhanced handling of objects, reduced weight, installation, and working ergonomics. Threading reinforcement elements horizontally from a side is not offering the worker an ideal working position, being time consuming in an unideal working position. In order to keep the strain on worker as low as possible, there is therefore a need for a method and a system to overcome the above-mentioned challenge of installing the reinforcement elements.

SUMMARY OF THE INVENTION

In the following and throughout the specification below, the following terms means; The term “shift” refers to one horizontal layer of building blocks installed. The term “building block system” refers to building blocks installed by stacking them side by side in a shift and height wise with several shifts completing a wall.

The term “reinforcement bars” refers to conventional elongated reinforcement elements or re-bars of circular or oval sections. The re-bars may either be made of steel or of a fibre reinforced material.

A main object of the present invention is to provide a simplified placing/installation of reinforcement elements in a building block system where building block elements are stacked height-wise in shifts.

Another object of the present invention is to provide a robust and efficient position of reinforcement elements during concrete pouring and concrete hardening.

It is also another object of the present invention to provide a system that may be adapted to existing building block system.

Yet another object of the present invention is to provide an improved installation method of reinforcement elements improving the HSE aspects during repeatedly installation work, placing the reinforcement horizontally from the top and down.

Yet another object of the present invention is to secure in a simple manner proper join reinforcement elements lengthwise together by providing an easy access to the reinforcement elements.

Moreover, it is an object of the present invention to provide a robust and efficient installation of reinforcement elements in a building block system due to handling, mounting, joining and concrete pouring.

Another object of the present invention is to provide a simplified installation method of reinforcement elements that is robust to heavy loads and keeps the reinforcement elements in position in order to withstand the heavy load when concrete is being poured from above.

Another object of the present invention is to provide a system allowing an efficient and cost effective production, handling and storage, thereby reducing the total production cost for each specimen and man hours spent.

Yet another object of the present invention is to provide a system allowing a more cost effective installation, also enhancing the health, environment and safety for the operators installing the reinforcement elements. It is also an object of the present invention to provide a system for installing two and two reinforcement bars in parallel, before next shift of building blocks being installed and thereby increasing the efficiency of installation by reducing number of work operations.

Another object of the present invention is to reduce labour time and reduce risk of operator while installing reinforcement elements in stacked building blocks, through eased installation and handling of elements and thereby also reduced load on shoulders and arms of operator.

The objects are achieved according to the invention by a reinforcement chair for installation of reinforcement elements for concrete in an insulating building block system as defined in the preamble of the independent claims 1 and 8, having the features of the characterizing portion of claim 1 and 8.

A number of embodiments, variants of alternatives of the invention are defined by the dependent claims.

In a first aspect, the present invention relates to a reinforcement chair for installation of elongated reinforcement bars in an insulating building block system where elements are stacked height-wise and concrete is poured in the room between at least two vertical sidewalls of stacked building blocks. The reinforcement chair comprises a lower part and an upper part where said lower part comprises a locking system for holding reinforcement bars in place and where said upper part comprises at least one cradle shaped area for reinforcement bars to rest and preventing them from sliding off the reinforcement chair. Said locking system, securing the reinforcement bars held in said lower part, is keeping the reinforcement chair in an upright position.

The locking system at the lower part of the reinforcement chair comprises a snapping device where at least two reinforcement bars are separately snapped at same height and parallel to each other, horizontally spaced apart.

The locking system of the reinforcement chair comprises at least two hollow rooms with an opening for the at least two reinforcement bars.

The hollow rooms of the locking system comprises at least one ridge making the hollow room tighter at the top of the ridge than the diameter of the reinforcement bar but formed with the characteristic of being flexible allowing the reinforcement bar to pass through by yielding the ridge.

The reinforcement chair at its upper part comprises at least two cradle shaped areas for individual support of at least two reinforcement bars at same height and parallel to each other, horizontally spaced apart.

Alternatively, the reinforcement chair at its upper parts comprises an arrangement for a locking system for individual snapping of the at least two reinforcement bars in connection to the at least two cradle shaped areas formed.

At least two protrusions are projecting out of the main structure of the reinforcement chair at a position of the reinforcement chair enabling the protrusions to project into a reinforcement chair being stacked with opposite face upon the previous reinforcement chair and being in a position where the protrusions are having a friction against the opposite reinforcement chair making a rigid connection.

In a second aspect, the present invention relates to a method for installation of a reinforcement chair for concrete in an insulating building block system where building blocks are stacked height-wise and concrete is poured in the room between two vertical sidewalls of the stacked building blocks by use of a reinforcement chair. The method allows installation of reinforcement bars in a shift of building blocks said reinforcement bars being lowered from the top and into contact with the reinforcement chair before stacking the next shift.

The method further comprise at least two reinforcement bars that are lowered down into a shift of building blocks and laid to rest in the step connecting vertical sidewalls of the building blocks, the reinforcement chair is lowered down to the at least two reinforcement bars installed where the at least two reinforcement bars are snapped onto the reinforcement chair keeping the reinforcement chair in an upright position, new at least two reinforcement bars are being lowered down onto the installed reinforcement chair, a new shift of building blocks are laid, and the installation of reinforcement bars, reinforcement chair and shifts of building blocks are being repeated to required height of the wall to be installed, a shift of building blocks completing the installation before pouring concrete in the hollow room of the shift of building blocks from above.

The reinforcement chair is sufficiently keeping the reinforcement elements in place during installation, concrete pouring and concrete hardening due to a robust material and construction.

The reinforcement chair is for simply installation of reinforcement elements in a building block system when need of extra reinforcement due to heavy load, like high earth pressure from gravel and soil on the outside of the wall to be installed. At normal loads, a center-center distance of approximately 600 mm between each vertical layer of reinforcement bars, where two and two elongated reinforcement bars are being installed in each shift, are sufficient for reinforcement purpose. For c/c of approximately 600 mm easy installation, where reinforcement elements are placed vertically by lifting and lowering them horizontally from above, are possible and admissible. When need of extra reinforcement a c/c of approximately 300 mm is required. By introducing the reinforcement chair, an easy installation through vertically lifting and horizontal lowering of the reinforcement bars from above is further achieved.

A simplified installation of reinforcement elements with for example a c/c of approximately 300 mm is made possible by introducing the reinforcement chair. After installing a building block shift, two reinforcement bars to be installed horizontally and in parallel are lowered down into a step, where the step, typically made in a plastic material, is connecting the vertical side walls of the building block together. A sufficient number of reinforcement bars are installed lengthwise to cover the whole length/circumference of shift with an overlap of for example about 500 mm for proper joining the reinforcement bars by steel wires or plastic strips or the similar. The reinforcement bars are installed in the upper part of the building blocks and rests in the steps. The reinforcement chair is to be installed, with the lower side with locking system directing down and by lowering it down into the intermediate space of the building block where the two reinforcement bars already installed are being snapped into the locking system through directing the bars by hand and pressing them into the locking system. The locking system secures the reinforcement bars firmly in place keeping the reinforcement chair in a stiff and upright position. The next pair of reinforcement bars is installed by lowering the bars down into recess areas in the reinforcement chair and joined in the same way as the previously specified. The next shift of building blocks is then installed and the same procedure of installing reinforcement bars and reinforcement chair is being repeated. When the desired height is achieved, the hollow space between the walls of the building blocks will be poured with concrete from the top, filling the entire voids with concrete.

The reinforcement chair may preferably be made of plastic material, but it may also be made in metall. The plastic material is preferably injection moulded in polyethylene (PE) or polypropylene (PP), while the metal may preferably be casted aluminum or steel.

As mentioned, today the extra reinforcement is to be threaded in from the side after one shift is laid. The idea behind the reinforcement chair is that before next shift is laid, a reinforcement chair can be placed in the previous shift and thereafter place the extra reinforcement bars, installing vertically from above, before installing next shift, giving the c/c 300 mm. This saves work while at the same time it is possible to get a regular bonding of the lengthwise reinforcement bars with steel wire or plastic strips.

Building blocks as elements in a wall system comprising two wall halves placed a distance apart and connected with two or more steps anchoring the two halves together. The steps are delivered preinstalled in the building blocks. The steps have reinforcement facilities that keep the reinforcement in place while filling concrete. In the void between the two walls, reinforcement elements are placed in the steps connecting the two walls together. Building blocks are placed in shifts/layer stacked upon each other and in each shift reinforced with reinforcement elements of elongated reinforcement bars placed in the steps. After stacking, reinforcing and possibly supported, the intermediate voids of the stacked building blocks are poured with concrete from top down. Area of application is typically foundation walls, walls in private houses, industrial premises, agricultural buildings etc. The side walls of the building blocks are typically made of expanded polystyrene, EPS, which are an isolating material.

The building block system comprises form elements stacked as building blocks and thereafter poured with a solid core of reinforced concrete.

Primarily, it is about horizontal installing of reinforcement elements. Vertically placement of reinforcement elements is usually only at extreme loads. The vertically installation of reinforcement elements is normally carried out after completing wall of one stories, but before filling all with concrete, by inserting vertically reinforcement element from the top of the wall.

The reinforcement chair should be able to adapt to existing building block system as well as new systems with same areas of use.

The reinforcement chair should be robust in order to not collapse, thus withstanding the impact and dynamic loads imposed by the green concrete during pouring.

A number of reinforcement chairs should be able to be stacked height wise upon each other prior to being installed in a layer/shift of building blocks, making it efficient for storage; easy for the worker to pick a stack of a number of reinforcement chairs bringing it to location of installation; and keeping them close and tidy and ease picking one by one for installation.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:

Figure 1 shows schematically a reinforcement system of prior art;

Figure 2a and 2b shows schematically and in perspective the two sides of the reinforcement chair according to the invention, intended for installing reinforcement elements;

Figure 3 shows schematically a vertical section typically between two shifts with an embodiment of a reinforcement chair according to the present invention installed within a building block;

Figure 4 shows a detailed end view in an enlarged scale of the lower end of a chair (partly shown) and a step indicated with the circle A of Figure 3 where the reinforcement bars are installed in the lower part of the reinforcement chair;

Figure 5a-5d shows schematically the stages of installing of two layers of building blocks with reinforcement chair and reinforcement bars therebetween.

Figure 6 shows schematically and in perspective the reinforcement bars installed in the lower and upper part of the reinforcement chair before loading a new layer of building blocks;

Figure 7 shows schematically a top view of the reinforcement chair marked with a detail A and a detail B;

Figure 8a and 8c shows schematically a detail A of figure 7 of projecting pins/ribs as means for stacking the reinforcement chair and detail B of figure 7 of lower part of the reinforcement chair showing a snap for snapping and keeping the reinforcement bar in place in the reinforcement chair. Figure 8b shows a detail A of figure 2b and a perspective view of figure 8a.

DETAILED DESCRIPTION OF EMBODIMENTS

The following description of the exemplary embodiments refers to the accompanying drawings. The drawings illustrate exemplary embodiments of the invention configured to be integrated in building block systems. The exemplary embodiments disclosed in the drawings should not be understood as a limitation to the scope of protection of the invention.

The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.

Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further particular features, structures or characteristics may be combined in any suitable manner or in one or more

embodiments.

In the description of the embodiments below, shifts with a height of 600 mm are the chairs used are configured to provide a vertical c/c distance between heights of reinforcement of 600 mm as a general rule and 300 mm in case of appearance of heavy external load on the wall. Figure 1 shows schematically a view of reinforcement bars 20 placed in stacked building blocks 30. The two reinforcement bars 20, seen in a step 31 in the middle of Figure 1 are those extra reinforcement elements that are required due to heavy load and that are inserted/threaded from the side of the building block 30.

Figures 2a and 2b show a perspective view of a reinforcement chair 10, showing front and back side of the reinforcement chair 10 for installing reinforcements in building block systems. The reinforcement is typically elongated re-bars of steel. The reinforcement chair 10 can hold two reinforcement bars 20 at lower part 11 of the reinforcement chair 10, where the reinforcement bars 20 rests on protruding ears and two or more reinforcement bars can rest at the upper part 12 of the reinforcement chair 10 in a cradle shaped area 16.

Figure 3 shows a vertical section through a part of a block wall with the reinforcement chair 10 installed in the building block system, here shown with one layer of building blocks 30 stacked upon another layer of building blocks 30 with reinforcement bars 20 both on bottom and top of the reinforcement chair 10. The building blocks are self-locking in the horizontal plane with alternating nobs and recesses fitting into alternating nobs and recesses of the next building block. Each building block has three steps 31, one at the upper, one at the middle and one at the lower part of the building block. The ones at the upper and lower side of the building block are identically but mirrored with protruding ears. At normal load on the wall, where only one layer of reinforcement bars 20 of each building block 30 are required, these reinforcement bars 20 are lowered down from above and placed in the step 31 of the upper side of the building block. The step 31 of the lower side of the building block, with ears protruding in opposite direction of ears of the step 31 of the upper side of the building block, are used when the need of extra reinforcement is required, and where the reinforcement bars are thought to be inserted from the side of the building blocks. The reinforcement chair 10 eliminates the operation of inserting the reinforcement bars 20 from the side at the lower side of the building block, replacing the need of the ears of the step 31 of the lower side of the building block with the reinforcement chair 10. The reinforcement chair 10 are placed in the upper side of the building blocks, raging upwards out of the building blocks 30 and, when the next building block 30 are stacked, raging into the next building block, snapping onto the reinforcement bars 20 lowered down at the step 31 prior to installing of the reinforcement bar 20. The firm connection to the reinforcement bars 20 at the lower part 11 of the reinforcement chair 10 ensures an upright position of the reinforcement chair 10.

Figure 4 shows a detail view A from figure 3. The Figure shows the reinforcement bars 20 placed inside the protruding ears as described in figure 2. According to the embodiment shown the ridges or snaps are shown within the protruding ears of the locking system 13 for snapping, the ridge is permanently pressed together by the reinforcement bar 20 and thus holding the reinforcement bar 20 tight in place in the reinforcement chair 10 and simultaneously keeping the reinforcement chair 10 in an upright position.

Figures 5a – 5d show schematically the steps of installing two layers of building blocks 30 with reinforcement chair 10 and reinforcement bars 20. Figure 5a shows a lower layer of building blocks 30 with placed reinforcement chair 10 and reinforcement bars 20. The reinforcement bars 20 are resting upon an upper part of a mid step 31 of the building block 30, which connects the two side wall elements of the building blocks 30 together. Figure 5b shows the reinforcement bars 20 installed inside the first layer of building blocks 30 together with the reinforcement chair 10. The reinforcement bars 20 are snapped into the protruding ears of the locking system 13 of the reinforcement chair 10, keeping the reinforcement chair 10 in place in an upright position. Figure 5c shows two more reinforcement bars 20 being installed at the top of the reinforcement chair 10, resting on top of the reinforcement chair 10 in a cradle shaped area 16 in upper part 12 of the reinforcement chair 10. Upper part 12 of the reinforcement chair 10 is raging out of first layer/shift and makes up a lower reinforcement layer of next layer/shift. Figure 5d shows the next layer/shift of the building blocks 30 installed. Upper part 12 of the reinforcement chair 10 is now shown to rage into the next layer/shift of building blocks 30, where the introduced reinforcement chair 10 allowed the installation of reinforcement bars 20 prior to the next shift/layer installed.

Figure 6 shows a perspective view of a layer/shift of the building blocks 30 where the reinforcement bars 20 are installed in the lower and upper part 11, 12 of the reinforcement chair 10 before loading a new layer/shift of building blocks 30 showing the reinforcement chair 10 with upper layer of reinforcement bars 20 raging out of the layer/shift it is installed into. First reinforcement bars 20 are lowered into a building block 30, resting on the step 31 at the upper part of the building block 30. A reinforcement chair 10 is being installed by snapping it onto the reinforcement bars 20 resting on the step 31 at the upper part of the building block 30. Two new reinforcement bars 20 are being placed on the cradle shaped area 16 of the top of the reinforcement chair 10 prior to stacking the next layer of building blocks. A new layer of reinforcement bars 20 are being lowered onto the step 31 at the upper part of the new building block 30 layer.

Figure 7 shows schematically a front view of the reinforcement chair marked with a detail A projecting fins/ribs as means for stacking the reinforcement chair and a detail B. The lower part 11 is pointing vertically down in the building blocks and the upper part 12 is pointing vertically up in the building blocks, but can be used facing independent of direction.

Figure 8a shows a detail of an upper corner of the reinforcement chair 10 while Figure 8b shows a perspective view of the same, showing protrusions 17 raging out of the corner. These protrusions are for stacking means, stacking a number of reinforcement chairs 10 upon each other as shown in figure 7. The protrusions 17 are placed to fit into tracks, openings or similar of the adjacent reinforcement chair 10 being stacked onto. Even though the protrusions 17 are shown in upper right corner and the diagonal placed corner of the, it is not restricted to those corners, neither being diagonally placed. They can be placed in every suitable corner of the reinforcement chair 10. It is not restricted to being placed in corner, but at any suitable place at the reinforcement chair 10 making the reinforcement chairs 10 able to be snapped/stacked upon each other in a firm connection, but easy to loosen from each other at installation site. Figure 8c shows detail of the protruding ears of the locking system 13 of the lower part 11 of the reinforcement chair 10. The reinforcement chair 10 has to be constructed to withstand high forces from concrete to be filled within the hollow room of the building block 30. The reinforcement chair 10 and also protruding ears of the locking system 13 are therefore robust and not very flexible to snap reinforcement bars 20 in place. A ridge 15 for snapping purposes is therefore an integrated part of the protruding ear of the locking system. Flexible formed to flex in order to make the reinforcement bars 20 pass into the locking system 13.

Different shapes of the reinforcement chair 10 are possible due to keep it strong and robust in order to withstand the high impact from both the reinforcement bars 20 and the concrete being filled. Ribs replacing or in addition to thick material or transverse struts crossing the open space of the reinforcement chair etc..

Table 1

Claims (9)

1. A reinforcement chair (10) for installation of elongated reinforcement bars (20) in an insulating building block (30) system where elements are stacked height-wise and concrete is poured in the room between at least two vertical sidewalls of stacked building blocks (30),

where said reinforcement chair (10) comprises a lower part (11) and an upper part (12) where said lower part (11) comprises a locking system (13) for holding reinforcement bars (20) in place and where said upper part (12) comprises at least one cradle shaped area (16) for reinforcement bars (20) to rest and preventing them from sliding off the reinforcement chair (10),

c h a r a c t e r i z e d i n that said locking system (13), securing the reinforcement bars (20) held in said lower part (11), is keeping the reinforcement chair (10) in a fixed upright position.

2. A reinforcement chair (10) according to claim 1, where the locking system (13) at its lower part (11) comprises a snapping device where at least two reinforcement bars (20) are separately snapped at same height and parallel to each other, horizontally spaced apart.

3. A reinforcement chair (10) according to claim 2, where the locking system (13) comprises at least two hollow rooms (14) with an opening for the at least two reinforcement bars (20).

4. A reinforcement chair (10) according to claim 3, where the hollow rooms (14) of the locking system (13) comprises at least one ridge (15) making the hollow room (14) tighter at the top of the ridge (15) than the diameter of the reinforcement bar (20) but formed with the characteristic of being flexible allowing the reinforcement bar (20) to pass through by yielding the ridge (15).

5. A reinforcement chair (10) according to any of the claims 1-4, where the reinforcement chair (10) at its upper part (12) comprises at least two cradle shaped areas (16) for individual support of at least two reinforcement bars (20) at same height and parallel to each other, horizontally spaced apart.

6. A reinforcement chair (10) according to one of the claims 2-5, where the reinforcement chair (10) at its upper parts (12) comprises an arrangement for a locking system (13) for individual snapping of the at least two reinforcement bars (20) in connection to the at least two cradle shaped areas (16) formed.

7. A reinforcement chair (10) according to any of the claims 1-6, where at least two protrusions (17) are projecting out of the main structure of the reinforcement chair (10) at a position of the reinforcement chair (10) enabling the protrusions (17) to project into a reinforcement chair (10) being stacked with opposite face upon the previous reinforcement chair (10) and being in a position where the protrusions (17) are having a friction against the opposite reinforcement chair (10) making a rigid connection.

8. A method for installation of a reinforcement chair (10) for concrete in an insulating building block (30) system where building blocks (30) are stacked heightwise and concrete is poured in the room between two vertical sidewalls of the stacked building blocks (30) by use of a reinforcement chair (10),

c h a r a c t e r i z e d i n that the method allows installation of reinforcement bars (20) in a shift of building blocks (30) said reinforcement bars (20) being lowered from the top and into contact with the reinforcement chair (10) before stacking the next shift.

9. A method for installation of a reinforcement chair (10) according to claim 8 c h a r a c t e r i z e d i n that at least two reinforcement bars (20) are lowered down into a shift of building blocks (30) and laid to rest in the step (31) connecting vertical sidewalls of the building blocks (30), the reinforcement chair (10) is lowered down to the at least two reinforcement bars (20) installed where the at least two reinforcement bars (20) are snapped onto the reinforcement chair (10) keeping the reinforcement chair (10) in an upright position, new at least two reinforcement bars (20) are being lowered down onto the installed reinforcement chair (10), a new shift of building blocks (30) are laid, and the installation of reinforcement bars (20), reinforcement chair (10) and shifts of building blocks (30) are being repeated to required height of the wall to be installed, a shift of building blocks (30) completing the installation before pouring concrete in the hollow room of the shift of building blocks (30) from above.