Wall Element
The invention relates to a wall element embodied in the form of a hollow precast concrete part comprising an internal wall, an external wall and a number of vertical channels which pass through the entire wall element from the top to lower faces thereof and whose cross-section reduces toward the wall base. When the wall element is positioned on the basement, it is possible to pour a cast-in-place concrete from the top into one or several vertical channels. The poured cast-in-place concrete attains through the channels, the wall base and further down in such a way that it penetrates into the basement or connecting elements. The hardened or solidified filling concrete forms a wedge which fixedly connects the wall element to a hollow brick of the basement.
This application is a U.S. National Stage of International Application No. PCT/EP2006/009364, filed Sep. 27, 2006, designating the United States and claiming priority from German Application No. 10 2005 048 147.7 filed Oct. 7, 2005, the disclosures of the foregoing applications being incorporated herein in their entirety.
BACKGROUND OF THE INVENTIONThe invention relates to a wall element in the form of a hollow precast concrete part, as well as a component kit for interconnecting structural members when erecting walls for a building, designed to withstand storms.
Factory-produced precast concrete parts have been used for more than half a century to quickly and cost-effectively erect the shell of a building. As compared to solid walls, hollow walls have the advantage that they can be stored easily and transported easier to the construction site because of the lower weight. Hollow-wall elements comprise an inside wall, an outside wall arranged parallel and at a distance thereto, as well as one or several hollow spaces between the inside wall and the outside wall. At the construction site, the relatively light-weight hollow wall element can thus be placed with the aid of a mobile crane from the truck directly onto a prepared foundation. The hollow spaces are subsequently filled completely or partially with concrete mixed at the job site. As a result, the completed walls have a load-bearing capacity, which is not inferior to that of a solid concrete wall that is poured on-site.
The known hollow wall elements for the most part are embodied as clamshell-type double wall. A hollow wall is known from International Patent Publication WO 91/028 58 A1, for example, which consists of panels that are spaced apart with the aid of spacers.
German Patent document DE 43 31 698 C2 describes a hollow wall in the form of a precast structural part, having a first wall part of concrete and a second wall part in the form of a panel, as well as a braced girder which rigidly connects the first wall part to the panel, forming a hollow space in-between. The braced girder comprises an upper member and a lower member, wherein the upper member is encased in a concrete cover with the concrete used for the first wall part.
A hollow wall is also known from patent document DE 30 03 162 A1, for which the spacing elements are embodied in the form of a ladder. Cross staves or diagonal staves are provided between posts, which define the distance and form the bars of the ladder-type spacing elements.
International Patent Publication WO 97/04195 A1 discloses a wall element embodied as a hollow concrete precast part, comprising an inside wall, an outside wall, and a number of vertical channels extending from the top to the bottom through the complete wall element.
Flat, rectangular hollow building blocks, with open hollow spaces at the bottom and at the top, are frequently used for the foundation of a prefabricated building. The dimensions for these hollow blocks are standardized. A number of such standardized hollow blocks are used for the foundation. The precast wall elements are then erected on this foundation. The building shell with one or several floors can thus be erected quickly and cost-effectively using precast concrete parts.
In regions endangered by storms such as hurricanes or tornados, special requirements demand solid construction at least for the ground floor of a building. If these requirements are to be met when using precast hollow wall elements, then a special reinforcing connection to the foundation is necessary, so that not only the vertical load burdens of the roof and/or the upper stories, but also the horizontal loads caused by the pressure of the earth and the wind can be conducted from the wall element into the stable foundation.
SUMMARY OF THE INVENTIONStarting with the content disclosed in International Patent Publication WO 97/04195 A1, it is an object of the present invention to create a wall element embodied as precast hollow concrete part, for which the wall base can be joined easily and in a secure manner to the foundation or other elements, so that traction forces can also be transferred. A component kit for interconnecting structural precast concrete parts should furthermore be provided, which makes it possible to construct at least the ground floor of a building so that it can withstand storms.
This object and other objects are solved with a wall element comprising: a hollow concrete precast part having a top and a bottom and including an inside wall, an outside wall, a wall base, and a number of vertical channels extending from the top to the bottom through hollow concrete precast part, each channel having a cross section that is tapered toward the wall base.
The objects are further accomplished with a component kit for interconnecting structural members, used for erecting the ground floor of a building and comprising: a number of ashlar hollow blocks, each having hollow spaces and a top with openings, the blocks being and arranged side-by-side to form a foundation; wall elements as described immediately above, for which the vertical channels are aligned with the hollow spaces of the blocks; and a free-flowing fill concrete that hardens inside the channels to form a wedge.
Accordingly, the wall element according to the invention has a number of vertical channels between the inside wall and the outside wall, which extend from the top to the bottom through the complete wall element and which have a cross section that is tapered toward the wall base. Once the wall elements have been erected on the foundation, concrete mixed on site or fast-curing concrete can be poured from the top into one or several of the vertical channels. Since the channels extend through the complete wall element, the filled in concrete flows through the respective channel and into the wall base region and from there can slide even further downward, until the foundation is reached or can enter into openings provided in the foundation. If the foundation consists of the aforementioned hollow blocks, then the fill concrete can flow through the channels into those hollow spaces. Conversely, any reinforcement projecting upward from the surface of the foundation, for example steel rods, can penetrate the wall element channels from below and can combine with the concrete filled into the channels to form a high-strength, reinforced steel wall anchor.
It is essential for the vertical channels inside the wall element to have a cross section that is reduced in the direction of the wall base, wherein the channel cross section is preferably tapered toward the wall base. Once the concrete filled into the channels has hardened and/or solidified, it forms a wedge that fixedly connects the wall element to the foundation. The wall element thus can no longer be lifted off the foundation and high traction forces, e.g. those occurring with a hurricane, can also be conducted via the conical walls of the channels and the concrete wedge into the foundation. The wall element embodied according to the invention is thus provided with a secure connection to the foundation, which can withstand high loads.
The proposed wall element can also be used in the same way for erecting the walls of upper floors, wherein the wall base in that case is connected to the ceiling of the floor below or directly to other wall elements.
The channels thus need only be filled with fast-hardening concrete to the level required for a secure, reinforced connection. The upper portion of a channel that is filled partially with concrete can be used for other purposes, for example for installing pipes, lines, or thermal insulation, without this resulting in a reduction of the load-bearing capacity with respect to ground pressure and wind, as compared to a solid wall.
It is advantageous if the channels inside the wall elements according to the invention have a rectangular cross section. With a wall thickness of 30 cm, for example, the channels have a thickness of 20 cm and a width of 40 cm, wherein it is also possible to have channels with a square cross section or to have round channels. The latter would then have to be embodied conically in downward direction.
Several channels are advantageously arranged parallel, side-by-side, wherein narrow webs extend between two adjacent channels, meaning between the inside wall and the outside wall. The inside walls of the channels in that case are preferably embodied smooth, so that the concrete or quick-drying concrete filled in from the top can slide downward unimpeded, if possible.
The reduction or tapering of the channel cross section, necessary for a good reinforcing connection, can be achieved in that the inside walls of the channels form an acute angle. It is not necessary in that case that the channel walls extend at an angle to each other over the complete height of the wall element. Rather, it is sufficient if the inside walls of the channels form an acute angle in the region of the wall base. A few degrees short of 90° are sufficient for the angle in order to achieve the desired wedge-forming of the fill concrete between the conical walls of the channels, preferably an angle between 80° and 85°. The required narrowing in the cross section can also be realized, for example, by a reduction of 1 mm per meter over the total length of the channel.
In principle, it is sufficient if the channels extend through the complete wall element, meaning from the top to the bottom. Filling the green or uncured concrete into one or several channels is made easier, however, if the respective channel is provided with a filling opening at its upper end. This filling opening can have edges that are slanted toward the inside, or it can be embodied as a small funnel. In the same way, a through opening to the foundation can be embodied at the lower end of the channel, making it easier for the concrete reaching the bottom to combine with the foundation or to enter the hollow spaces in the hollow blocks used for the foundation.
To ensure a secure, reinforced connection between the wall element and the foundation, it is important to make sure that the concrete filled into the channels has flown down to the very bottom. Small control openings are therefore advantageously provided at the very bottom of the outside wall, which provide a view of the channel located behind it.
The wall element according to the invention is preferably a single precast concrete part. Wire rods or reinforced steel mats can be inserted as reinforcing material in the area of the thin, but solidly embodied inside and outside wall, as well as in the webs between the channels, in order to increase the load-bearing capacity of the wall element, especially relating to the traction and flexural strength.
Particularly suitable for producing the wall element is a type of concrete, which is referred to as “self-compacting concrete (SCC)” in English. The SCC has optimum green concrete properties, especially for the production of thin-walled precast parts, which can be adjusted by using different types of concrete starting materials and different compositions. The SCC has the ability to flow freely, without demixing in the process. A suitable SCC is composed, for example, of cement, coal fly ash as additive, flow agents, and water. A more detailed description can be found in the essay by H. Grube and J. Rickert: “SELBSTVERDICHTENDER BETON—EIN WEITERER ENTWICKLUNGSSCHRITT IN DEM 5-STOFF-SYSTEM BETON” [Self-Compacting Concrete—A Further Step in the Development of the 5-Material System Concrete], published in the magazine “beton” 49 (1999), Issue 4, pages 239-244.
Particularly advantageous is the use of wall elements according to the invention in conjunction with a foundation consisting of a number of standardized, ashlar hollow blocks with rectangular openings. In that case, the vertical channels in the wall element are arranged and dimensioned such that the channels are aligned with the hollow spaces in the blocks that are open at the top. The hollow spaces in the blocks thus form so-to-speak extensions of the channels, into which the concrete is poured from the top, has flown toward the bottom, and has hardened there into solid concrete wedges that fixedly connect the wall element to the hollow blocks of the foundation.
An exemplary embodiment of the invention is described in the following with the aid of the enclosed drawings, which show in:
Pre-cast concrete parts are used for producing the corner for the ground floor of a building shell, shown in
The long wall element 2 consists of a flat inside wall 4 and a parallel-arranged also flat outside wall 5, wherein openings for a door 6 and a window 7 are worked in at the same time. Narrow channels 8 extend from the top to the bottom through the wall element 2, between the inside wall 4 and the outside wall 5. Six channels 8 are arranged parallel and side-by-side in the corner area, while three additional channels 8 are embodied between the door 6 and the window 7 and an additional two channels 8 are embodied to the left of the door 6. All channels 8 have a rectangular cross section. Each channel 8 is provided with a filling opening 9 at its upper end and a flow-through opening 10 at its lower end. Respectively two adjacent channels 8 are separated by a thin web 11. The wall element 2 with the channels 8 is cast in the form of a one-piece part of self-compacting concrete (SCC). The wall element was then transported from the factory to the construction site and was placed with the aid of a mobile crane onto the foundation.
Round steel rods 12 project vertically upward from the hollow blocks 1 of the foundation and through the openings 10 into the channels 8. Fast hardening concrete was poured from above through the filling openings 9 into the channels 8, which then flowed downward and hardened at the bottom into a wedge of fill concrete 13.
Small rectangular control openings 14 at the lower edge of the outside wall 5 provide a view of the channel 8 located behind, thus making it possible to check whether the channel 8 is empty or filled with concrete 13. Prior to filling in the concrete, these control openings 14 allow inspecting the reinforcement in the joining area.
Claims
1. A wall element, comprising:
- a hollow concrete precast part having a top and a bottom, and including, An inside wall, an outside wall, a wall base, and a number of vertical channels extending from the top to the bottom through the hollow concrete precast part, each channel having a cross section that is tapered toward the wall base.
2. The wall element according to claim 1, wherein the cross section for the channels is tapered in a downward direction.
3. The wall element according to claim 1, wherein the channels have a rectangular cross section.
4. The wall element according to claim 3, wherein a plurality of the channels are arranged parallel and side-by-side, and the hollow concrete precast part further includes narrow webs that extend respectively between two adjacent channels, between the inside wall and the outside wall.
5. The wall element according to claim 1, wherein the channels are bounded by inside walls that are smooth.
6. The wall element according to claim 5, wherein at least in a region of the wall base the inside walls of the channels form an acute angle relative to the wall base.
7. The wall element according to claim 1, wherein the channels have an upper end with an opening for filling in a concrete mixed on site and a lower end with a through opening to a foundation for the wall element.
8. The wall element according to claim 1, wherein the outside wall has a lower edge region that comprises control openings to permit a view of the channel located behind the control openings.
9. The wall element according to claim 1, wherein the hollow concrete precast part comprises a poured, one-piece concrete element.
10. The wall element according to claim 9, wherein the hollow concrete precast part is produced of self-compacting concrete (SCC).
11. A component kit for interconnecting structural members, used for erecting the ground floor of a building and comprising:
- a number of ashlar hollow blocks each having hollow spaces and a top with openings, the blocks being arranged side-by-side to form a foundation;
- wall elements as defined in claim 1, for which the vertical channels are aligned with the hollow spaces of the blocks; and
- a free-flowing fill concrete that hardens inside the channels to form a wedge.
12. The wall element according to claim 6, wherein the acute angle is between about 80° and about 85°.
Type: Application
Filed: Sep 27, 2006
Publication Date: May 28, 2009
Inventor: Mathias Reymann (St. Petersburg, FL)
Application Number: 12/083,200
International Classification: E04C 3/34 (20060101); E04G 21/04 (20060101);
