A COMPONENT SYSTEM FOR THE CONSTRUCTION OF GROUND-BEARING STAIRWAYS, PLATFORMS, TERRACES, AND THE LIKE

Abstract: The invention relates to a prefabricated concrete component system for forming ground-bearing stairways, platforms, terraces and analogous structures of one or more layers. It is the object of the invention to be able to construct, from a few basic components, a durable and safe ground-­ bearing structure of the desired shape. Such a component system comprises at least three different basic components (1, 2, and 3), which are used together or separately and which are slab components provided with upright supports. The basic components of the component system according to the invention are so designed that one or two adjacent slab components in the same constructional layer form at least two support and fastening surfaces for the next higher slab component. Thus a sturdy and safe structure is obtained. The shape of the components enables them to be cast in a single-part casting mold, from which the component will detach owing to beveled surfaces. The system also includes ramp components, edge components provided with edges, and corner components.

Description: The present invention relates to the component system defined in the preamble of claim 1 and to the components defined in the preambles of claims 17-20. The system is made up of prefabricated concrete components which are assembled and fastened to each other in a suitable manner to form ground-engaging flights of steps, and ramps in pedestrian areas and in the surrounds of buildings, for example in connection with entrances (See, for example, US-A-3 813 831). The use of various so-called landscaping products made of concrete is rapidly increasing in Europe and also in Finland. This increase is due to the general trend in the building industry to shift into the factory as large a proportion as possible of the work to be done, as compared with in situ building. Nowadays, short flights of steps or a few ground-engaging steps are most commonly assembled from concrete products manufactured for other purposes, such as rectangular slab and block pavings and curbstones. There is often the disadvantage of unsuitable dimensioning, inferior appearance, and, as a safety decreasing factor, the fact that the parts cannot be fastened to each other in a durable manner. This has inhibited the construction of long, steep but safe heavy-use flights of steps from separate parts. For this reason, ground-engaging flights of steps are today mostly cast in situ in one piece. The disadvantages of in-situ casting include high cost, especially in winter conditions, a low quality of the visible surfaces, and the difficulty of achieving sufficient resistance to freezing temperatures as regards the concrete. Under factory conditions, control is more thorough, ensuring higher quality. Attempts are often made to improve the outer appearance by cementing concrete slabs to the steps, which for its part complicates the work. Simple separate step components and retaining-wall components, as well as curbstones, have been available on the market. However, owing to dimensional and shape incompatibility and to differences in color, it is impossible to assemble these separate parts into a neat structure. The accompanying figures I-V depict the ground-bearing step components currently used. They have a great disadvantage in that they cannot be fastened to each other to form framework structures. The ground underneath will serve as the loadbearing structure. Their installation is difficult and slow. In addition, the structure is subject to ground shifts, for example to frost heave. It is the object of the present invention to overcome the disadvantages mentioned above and to provide a component system which fulfills the functional and production-technique requirements listed below: Because of the risk of shifts in the sub-base it must be possible to fasten the parts to each other and to overlap them. This is both a structural durability requirement and the user's safety requirement. The fastening points must remain hidden in the completed structure; the visible surfaces must be acceptable in terms of quality, and, in particular, the surfaces to be walked on must not be slippery; the concrete must be resistant to freezing temperatures and to road salt; it must be possible to construct ground-engaging flights of steps, intermediate landings, ramps, and inner and outer corners from only a few basic components of different shapes; in terms of production technology, the design of the products must be such that the molds required are single-part molds in order that the products can be cast like "sand cakes" (sand castles) from zero-slump concrete. In addition, the visible surfaces must be cast against the mold wall in order to achieve a high-standard outer appearance and non-slippery structure. All these objectives are achieved using the component system according to the invention, the main characteristics of which are given in the characterizing clause of claim 1, and using components belonging to it, the main characteristics of which are given in the characterizing clauses of claims 16-20. A component which is disposed on top of another is fastened to these support and fastening surfaces by nailing, for example shooting, by means of a wedge bolt, or by a corresponding method based on drilling a hole, or by cementing. The fastening point will be concealed by the upper of the slab components. Cementing is advantageous especially in the edge slabs of the top landing and in intermediate landings, where the fastening must not be visible. The upright support of a slab component preferably consists of a ridge parallel to its front and rear edges. The ridge preferably extends across the entire slab component. According to a preferred embodiment of the component system, all of the components have the same width. According to a preferred embodiment of the slab component, its dimensioning is such that the width of the slab component, i.e. its dimension in the direction of, for example, the width of the steps, is twice the tread of the structure, i.e. the overlap of the structure in the direction of depth. This is necessary in order to achieve the structure of the outer and inner corners of flights of steps and platforms in such a way that the same pitch and overlap continue at an angle of 90° in relation to the original direction of the tread. Instead of an upright support in the form of a straight ridge, the corner components have an upright support which forms a corner. The width of the slab components which are to be placed at the edges of the structure is the same as the width of the other slab components, or half of it. The edge components have edges of the height of the upright support in order to produce a closed wall structure. All of the mutually opposite upright surfaces of a slab component, i.e. all the side walls of the upright supports and of the slab component itself, are inclined upwards and inwards. This inclination is obtained in the upright surfaces such that it is possible to use single-part casting molds. This means that the mold need not be opened for removing the slab from the mold; inverting the mold or pushing the casting through the mold will suffice. In connection with the casting it is possible to produce an anti-slip roughening, either in the mold itself or by using negative surface retarders, i.e. so-called "exposed-aggregate finish". The component system according to the invention preferably comprises basic components of two different types, i.e. step components and inner components. Extendible in the vertical direction from the upper surface of the step component is an upright support at the end of the step distance, i.e. the tread, and the step component to be placed on top of this component will start there. Vertically successive step components will form the steps in the structure. The inner component has two upright supports fitted symmetrically in relation to the center line of the inner component, and the depth of the inner component is preferably twice the tread, i.e. the step length. Since the width of the components is preferably twice the tread of the structure, the inner component is thus preferably square. The inner part of the structure is built using inner components, and they are thus disposed next to the components closest to the edge, which are either step components or other edge components. Inner components are preferably used turned 90° about their vertical axis in vertically successive layers, whereby a considerably more advantageous distribution of loads will be obtained. There are preferably two different types of step component. One of the components has the same length as the inner component, i.e. twice the tread, and the other has 1.5 times the length of the inner component, i.e. three times the tread. The former has only one upright support and the latter has two, one of the upright supports being located at or close to the rear end of the component. By selecting the depths of the step components so as to correspond to 2 or 3 times the tread, it is possible to avoid the need for various adjusting pieces in the edges of the structure, in the intermediate layers and in the ramps. Even shorter step components can be used. In addition, the component system according to the invention includes ramp components for forming ramps between the various levels. There are preferably two types of ramp component. One is a single-part component and has the same length as the inner component and forms a steep ramp. The other has two or more parts and has a total length which is a multiple of that of the inner component, and it forms a gently sloping ramp. The steep ramp component has a shoulder serving as an upright support at the tread distance from the front edge. The part between the shoulder and the front edge forms a sloped surface which runs from the bottom level of the slab to the shoulder, and even to a level slightly higher than the shoulder, corresponding to the step level of the component to be placed on top. The parts of the gently sloping ramp component have the length of the inner component, and the highest part has a shoulder serving as an upright support at the tread distance from its front edge. The ramp parts together form a continuous sloped surface which runs from the front edge at the bottom level of the slab, to the shoulder, and on upwards to a level somewhat higher than the shoulder, corresponding to the step level of the component to be placed on top. The upright walls of the ramp components are slightly inclined upwards and inwards, and they are cast in the same manner in single-part casting molds. The visible sloped surface is formed against the wall of the casting mold and is thus defined by the mold, and is neat. The components may be tolerant to heating so that it will be possible in the winter to melt ice from their surface. The heating may be carried out, for example, by using electric resistors placed between those upright supports of the step components which are closest to the edge. In the case of a flat structure made from the components, all of the components may be heatable by electric resistors placed under them. To supplement the components mentioned above there are needed flat surface slabs the width and length of which correspond to the dimensioning of the inner components and the edge components. Prior-art concrete ground-engaging step components, as well as preferred embodiments according to the present invention, are described below with reference to the accompanying figures, in which Figures I-V depict the prior-art concrete ground-bearing step flight components which were already described above, Figure 1a depicts a step component provided with two upright supports, Figure 1b depicts a step component provided with one upright support, Figure 1c depicts an inner component, Figure 2a depicts an edge component corresponding to the inner component, Figure 2b depicts a half of an edge component, Figure 3a depicts a steep ramp component, Figure 3b depicts a gently sloping two-part ramp component, Figure 4a depicts a vertical section of an inner corner component, Figure 4b depicts a plan view of an inner corner component, Figure 4c depicts an inner corner component in a step flight corner structure, Figure 5a depicts a vertical section of an outer corner component, Figure 5b depicts a plan view of an outer corner component, Figure 5c depicts an outer corner component in a step flight corner structure, Figures 6-8 depict ground-engaging flights of steps constructed by using the various components, Figure 9 depicts a ground-engaging intermediate landing, Figure 10 depicts a ground-engaging ramp structure, Figure 11 is a perspective representation of a flight of steps embedded in the ground and trimmed using edge components, and Figure 12 is a perspective representation of a planting platform and platform steps constructed in connection with it. In the Figures, the same parts are indicated with the same reference numerals. A step component provided with two upright supports is indicated by reference numeral 1, a step component provided with one upright support 11 with numeral 2, an inner component with numeral 3, an inner component having an edge 17 with numeral 4, an inner-component half with an edge 17 with numeral 5, a steep ramp component with numeral 6, the support part of a gently sloping two-part ramp component with numeral 7, and its extension part with numeral 8, an inner corner component with numeral 9, and an outer corner component with numeral 10. The bottom surface of the slab is indicated by number 12 and the upwards and inwards inclined upright walls of the components are indicated by number 13. Figures 1-3 show clearly the shapes of the individual basic components and their mutual dimensional proportions. All of the upright surfaces (13) are inclined upwards and inwards, which enables the components to be cast in single-part molds, inverted with respect to the Figures. The cast products will detach from the molds owing to their inclined sides 13 when the molds are inverted. This considerably simplifies the manufacture of the components. Owing to this manufacturing method, all the visible surfaces, such as the step surfaces and the ramp surfaces, are smooth and provided with the desired roughening pattern, since they are formed against the walls of the casting molds. In connection with the casting there is obtained, in addition to the roughening, also any desired rounding of the noses of the step surfaces and possibly other edges. The rounding of the nose is the most visible of them. The rounding of the lower edges can, when so desired, be done in connection with the casting. Since the casting of the components takes place indoors under controlled conditions, their quality will be maximally high. When flights of steps are built, the rise and the tread of a step depend on each other and they have clear practical limit values. The higher the rise, the shorter is the tread. Each selected rise-tread combination thus has its own dimensional series of all components. The dimension series depicted in the figures illustrates a preferred rise to tread ratio, in which the tread is 400 mm and the rise 150 mm. The depth of the step, which is the same as the tread, is thus 400 mm, and the width of the components is a multiple of the tread, preferably twice the tread, i.e. 800 mm. To produce corner structures, the width must be twice the tread in order that the same pitch and overlap can continue at an angle of 90° to the original direction of the tread. The depth of the inner component is twice the tread, i.e. 800 mm, and the same as the depth of the step component provided with one upright support. The depth of the step component provided with two upright supports is 1200 mm. The thickness of the upright supports in the depth direction of the component is approximately 70 mm, and their mutual distance in the inner component is 170 mm and distance from the edges 245 mm. The thickness of the slab is approximately 50 mm. With this dimensioning, the weight of each component is less than 150 kg, and they are thus capable of being handled manually by using suitable auxiliary tools. Figures 4 and 5 show the structure of corners for flights of steps Figure 4c depicts an inner corner and Figure 5c an outer corner. The width of the step components is the same as twice the tread, i.e. the same as their depth. To form straight flight edges there are additionally needed halves of step components, i.e. components of half the width dimension. Figures 6-8 depict different solutions for ground-engaging flights of steps. Figure 6 depicts a structure on a gently sloping terrain, Figure 7 on a slightly steeper terrain, and Figure 8 on a steep terrain. All the flights of steps have been constructed using the same basic components, i.e. with the same rise to tread ratio. In the gently sloping structure, nothing other than step components 1 with two upright supports has been used. The sub-base used for the components is gravel, which is compacted under the components. The Figure shows that each component is supported at two points, i.e. where they lie on the upright supports of the component underneath. These support points are indicated by black triangles in Figures 6, 7 and 8. The lowest component is ground-engaging. Vertically successive components are fastened to each other at said supporting points. The top layer, as well as the paving in front of the steps are made from ordinary concrete slabs. The slab fitted on top of the step component is fastened by cementing to the upper surface of the upright supports. Thus also the fastening of the top slab will be invisible. The adhesive used may be conventional concrete adhesive such as cement, bitumen cement or epoxy cement. The stairway of Figure 7 constructed on a terrain steeper than the terrain described above has been made from step components 2 provided with one upright support and from inner components 3. Located symmetrically in relation to the center line 22 of the component, the upright supports of the inner component 3 each support a separate upper component, i.e. in the case shown in the Figure the step component 2 and the inner component 3. In the lowest layer of components and in the middle layer there are two adjacent components 2 and 3, whereas the top layer has only one step component 2. The top layer does not require two adjacent components, since the load on it is small. Since this embodiment is a step flight structure, the most common component is always a step component. Each component is again supported at two upright supports underneath and is thus firmly in place. The fastening is done, for example, by nailing at concealed points or by cementing at visible points. At the foot of the step flight and at its upper end there are conventional slabs. In Figure 8, the step flight constructed on a steep terrain has been formed from three different basic components 1, 2 and 3. The only component 1 of the middle step is exceptionally supported at three points. The top step layer again has, because of the small load, only one step component 2, provided with one upright support. If more steps were needed, the construction could be continued inwards in order to provide sufficient support for the structure. An inner component 3 would be suitable as a continuation of the component 3 in the lowest layer and as the continuation of the component 1 in the middle layer. In this case the step component 2 of the topmost layer should be replaced by a step component 1. A step component 2 would again be suitable as the topmost additional step. The three basic components described thus suffice for the construction of ground-engaging flights of steps of any shape. Figure 9 depicts a simple intermediate-landing structure and Figure 10 a ramp structure applied to a slight rise of terrain. Since the ramp components 6, 7 and 8 have the same basic dimensioning as the step component with one upright support and the inner component, they can be used in any top layer of the structure, side by side with step components and flat slabs. The ramp components differ from the other basic components in that they have an even, sloped surface. In the parts 6 and 7 this surface extends sufficiently higher than the upright support so that the top surface is at the same level as the step level of the next component layer. Thus the ramp surface forms a smooth cross-over bridge between two components at different levels. The sloped upper surface ends at the front edge of the upright support and thus forms a shoulder on which the component of the next layer will bear. The continuation part 8 of the two-part ramp component does not have said shoulder; the continuation part joins its front part 7 so that the sloped surfaces of both form a continuous smooth sloped surface. Figure 11 depicts a flight of steps which is embedded in the ground; its edge components are provided with upright edges which form a retainer for a lawn, for example. Figure 12 is a perspective representation of a planting platform and platform steps. All of the edge components have been provided with upright edges to form a closed wall. The embodiments described and depicted above are only examples of how the component system according to the invention can be applied. It is possible to design and produce in a simple manner strong, safe and neat ground-engaging structures of the desired shape by using the basic components described, together with additional components complying with the same dimensioning, such as slabs, edge components, rounded components, etc.

Claims: A ground-engaging flight of steps built from a component system which comprises a set of concrete slab components each having a slab and a generally perpendicular support for engaging the adjacent component of a next layer of the flight of steps and thereby supporting the upper of said adjacent layers from the lower said layer, said support of each slab component having at its end remote from the slab a surface which is made parallel with the slab, and each slab component having upright surfaces which diverge from the horizontal plane of the slab such that in all cases of mutually opposite upright surfaces at least one of the two surfaces is inclined with respect to the other to enable releasing from a casting mould; characterised in that the component system preferably comprises at least three different types of concrete slab component (1,2,3,4,5,9 and 10) each component type having at least one support (11) extending upright from its upper surface, each said support of each slab component having the same height as any other upright support on that slab, the slab components being arranged close to each other so that each of at least two adjacent supports in one layer are situated below the slab part of one slab component in the next higher layer; in that the bottom surface (12) of said slab part is plane and perpendicular to the supports; in that the steps each have a tread defined between a front edge of the slab component and an adjacent said upright support (11); and in that the slab types differ in the number of upright supports (11) each has and/or in the depth of the slab component, where the depth is always an integral multiple of the tread depth. A flight of steps according to claim 1, characterized in that the upright supports (11) of two adjacent slab components (1 and 3) in a layer of the structure form three support and fastening surfaces for one upper slab component (1). (Fig 8). A flight of steps according to claim 1, characterized in that the upright support has the form of a ridge (11) parallel to a front edge of the slab component. A flight of steps according to claim 3, characterized in that the ridge (11) extends across the entire slab component. A flight of steps according to either of claims 1 and 2, characterized in that a corner component (9, 10) of the structure has an upright support having the shape of a corner. A flight of steps according to any of the above claims, characterized in that all of the slab components (1-10) of the component system have the same width. A flight of steps according to any one of the above claims, characterized in that the width of the slab component (1-10) is twice the step depth, i.e. the tread of the structure. A flight of steps according to any one of claims 1-5, characterized in that the width of the edge components (20, 21, 22) of the structure is the same as the width of the other components, or one half or three halves of it, in order to result in overlapping joints. (Fig. 11 and 12). A flight of steps according to any of the above claims, characterized in that the edge components (4 and 5, Fig. 1A, 2B and 13) of the structure have an edge (17) parallel with the support forming ridges (11) and having the height of the upright support (11) in order to produce a closed wall structure system. A flight of steps according to any of the above claims, characterized in that the step component (1, 2) forming the step part of a flight of steps has an upright support (11) which is located at the distance of the tread, i.e. the step depth, from the front edge. (Fig. 1A, 1B and 5C). A flight of steps according to any of claims 1-9, characterized in that the inner component (3) forming the inner part of the structure has two upright supports (11), the opposed inner sides of said supports being symmetrically situated in relation to its center, and that the distance of the center line (22) from the edges of the inner component corresponds to the tread, i.e. the step depth. A flight of steps according to claim 10, characterized in that the depth of the step component (2) is the same as the depth of the inner component (3) and that said step component has only one upright support (11). A flight of steps according to claim 10, characterized in that the depth of the step component (1) is 1.5 times the depth of the inner component (3) and that there is a second upright support (11b) at its back edge. (Fig. 1A) A flight of steps according to any of the above claims, characterized in that the component system includes includes a ramp component (6) the depth of which is the same as the depth of the inner component (3) and which has a shoulder (18) serving as an upright support at the distance of the step depth from the front edge, as seen in the using direction, the part between the shoulder and the front edge forming a sloped surface (19) which ascends from the step level of one layer to the step level of the next higher layer. A flight of steps according to any of claims 1 to 13, characterized in that the component system includes includes a ramp component (7, 8) comprising two or more parts, the total length of the ramp component being a multiple of the depth of the inner component (3) and its highest part having a shoulder (18) serving as an upright support, the part between the shoulder and the front edge forming a sloped surface (19) which ascends from the step level of one layer to the step level of the next higher layer, said parts of the ramp component each having the length of the inner part (3), i.e. two step tread lengths. A flight of steps according to any of claims 1 to 10, in which the component system includes an or a said inner component, has two upright supports (11), the opposed inner sides of the said supports being symmetrically located in relation to the centre line (20) of said component and closer to the centre line than to the end edges, said supports being of the same height and having an upper surface which is parallel to the slab part, and the bottom surface of said slab part being planar and perpendicular to the supports. A flight of steps according to any one of claims 1 to 9, characterized in that the component system includes a step component which has two upright supports, one (11) of them being located at the distance equal to the tread, i.e. the step depth, from the front edge and the other (11b) being located at or near the back edge of the component; and in that the depth of the component is three times the step depth, said supports being of the same height and having an upper surface which is parallel to the slab part, and the bottom surface of said slab part being planar and perpendicular to the supports. A flight of steps according to any one of claims 1 to 9, characterized in that the component system includes a step component which has one upright support (11), which is located at the distance of the tread, i.e. the step depth, from the front edge; and in that the width of the component is the same as its depth, said support having an upper surface which is parallel to the slab part, and the bottom surface of said slab part being planar and perpendicular to the support. A flight of steps according to any one of claims 1 to 13, wherein the component system includes a ramp component having its depth the same as that of the inner component (3); wherein the ramp component has a shoulder (18) serving as an upright support at the distance of the step depth from the front edge, the part between the shoulder and the front edge forming a sloped surface (19) which ascends from the step level of one layer to the step level of the next higher level, the bottom surface of the ramp component being planar and perpendicular to the imaginary support formed by said shoulder. A flight of steps according to any one of claims 1 to 13, wherein the component system includes a ramp component which comprises two or more parts (7, 8), whose total depth is a multiple of the depth of the inner component (3); wherein there is a shoulder (18) in its highest part serving as an upright support, the part between the shoulder and the front edge forming a sloped surface (19) which ascends from the step level of one layer to the step level of the next higher layer, said two or more parts of the ramp component having the depth corresponding to the depth of two steps, and the bottom surface of the two or more parts being planar and perpendicular to the imaginary support formed by said shoulder.

Inventors: MANNONEN, MATTI PELLERVO
Applicants: TRIOPLAN OY
Application year: 1989
Main classification: E04F11
IPC codes: E04F11, E01C9, E02D17