Abstract:
A method for producing a machine table foundation has a table top wherein the in-situ concrete is cast on at least one concrete semifinished part which is positioned in the machine table foundation in the final position of the semifinished part. A machine table foundation has a table top that has at least one concrete semifinished part and an in-situ concrete cast on the concrete semifinished part. The at least one concrete semifinished part is used for a table top of a machine table foundation.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the US National Stage of International Application No. PCT/EP2014/072083 filed Oct 15, 2014, and claims the benefit thereof. The International Application claims the benefit of German Application No. DE 102013221283.6 filed Oct 21, 2013. All of the applications are incorporated by reference herein in their entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to a method for producing a machine table foundation having a table top supported by at least one pillar, in which method in-situ concrete is poured in order to produce the table top. The invention also relates to a machine table foundation having a table top supported by at least one pillar, and to a use of at least one concrete semifinished part. 
       BACKGROUND OF INVENTION 
       [0003]    The machine foundation has, inter alia, the purpose of carrying a load of a machine (machinery), for example a turbine unit, placed in a stationary manner. A known variant of a machine foundation is a machine table foundation that has at least one self-supporting pillar and a table top supported by the pillar, on which table top the machine is placed. 
         [0004]    Reinforced concrete is usually used as a material for the table top. Typical minimum dimensions of a table top of a machine table foundation that is used for example for a turbine unit are a width of approximately 13 m, a length of approximately 30 m, and a thickness of approximately 2 m. 
         [0005]    A table top having such dimensions is unsuitable for road transport. The table top is therefore usually produced on a construction site (“on-site”), i.e. at an intended installation site of the machine, by pouring in-situ concrete. 
         [0006]    The following method is generally used when producing the table top: at least one pillar is firstly placed in position. A supporting frame, a formwork, and an operating floor are then constructed above the pillar. Here, one function of the supporting frame is to vertically carry a load of an in-situ concrete cast subsequently. The formwork serves inter alia as a shaping for the in-situ concrete. The task of the operating floor is to enable access to the in-situ concrete in order to carry out construction work. Reinforcement is then arranged within the formwork. In-situ concrete is then poured into the formwork, in which the in-situ concrete cures. Once the in-situ concrete has cured and has become self-supporting—which may take approximately 28 days—the supporting frame is disassembled. 
         [0007]    Since it is the cast table top itself that prevents access to the supporting frame from above, it is not possible to use a crane to disassemble the supporting frame. The supporting frame is therefore usually disassembled by hand from the bottom, which is usually time-consuming and/or labor-intensive. 
       SUMMARY OF INVENTION 
       [0008]    An object of the present invention is to enable a construction time reduction when producing a machine table foundation. 
         [0009]    This object is achieved by a method, by a machine table foundation, and/or by a use according to the features of the respective independent claims. 
         [0010]    The invention proceeds from the consideration that one or more concrete semifinished parts can take on the function of a supporting frame—specifically carrying a load of an in-situ concrete vertically. Consequently, by pouring in-situ concrete onto one or more concrete semifinished parts it is possible to dispense with the supporting frame, which otherwise vertically carries the load of the in-situ concrete, or at least with parts of the supporting frame, whereby the time required to assemble and/or disassemble the supporting frame or parts of the supporting frame at the construction site is saved. 
         [0011]    The invention is also based on the concept that construction access under the table top or at least under parts of the table top can be achieved earlier already by pouring in-situ concrete onto one or more concrete semifinished parts. There is no need to wait until the in-situ concrete is self-supporting before starting to work under a concrete semifinished part. Rather, as soon as the concrete semifinished part is positioned in its end position, work can be performed under the concrete semifinished part contributing to the formation of the table top in parallel with work to produce the table top. Due to the absence of the supporting frame or parts of the supporting frame, there are also fewer obstacles when working under the table top. 
         [0012]    Construction access provided earlier under the table top may be of great advantage in the case of a machine table foundation, in particular in the case of a machine table foundation for a turbine unit, since it may be that additional apparatuses, for example a condenser, are arranged under the table top. 
         [0013]    An in-situ concrete can be understood to mean a concrete that is processed on a construction site. The in-situ concrete is usually poured into a formwork, in which the in-situ concrete can cure. 
         [0014]    A formwork may be a casting mold, in particular for production of concrete components. Once the in-situ concrete has cured in a form predefined by the formwork, the formwork is generally removed. The formwork can be composed of a plurality of formwork elements, which in particular are planar. 
         [0015]    A concrete semifinished part can be understood to be a concrete component that is pre-fabricated, in particular in a factory, and is in particular a reinforced concrete, which is intended for further processing with the aid of the in-situ concrete. The further processing usually takes place at a location different from the factory, for example on a construction site (“on-site”) or at the site of installation of the machine. The further processing may include, for example, a pouring of the in-situ concrete onto the concrete semifinished part. An integral bond may form at an interface between the concrete semifinished part and the in-situ concrete. The concrete semifinished part may also be suitable for road transport on account of its dimensions. 
         [0016]    The concrete semifinished part may have a concrete body that in particular is substantially cuboidal. In order to compensate for deformations caused by the load of the in-situ concrete, the concrete semifinished part can be fabricated ex factory in a cambered manner, i.e. the concrete semifinished part may have a curvature that flattens under the load of the in-situ concrete. 
         [0017]    It is expedient that the concrete semifinished part has elements that are designed especially for the further processing with the aid of the in-situ concrete. Such elements may be, for example, reinforcement bars of a composite reinforcement, which bars can be embedded in portions in the concrete body. 
         [0018]    A reinforcement may be understood to mean a grating that is embedded at least in portions in a concrete component. The grating may consist of a plurality of bars, in particular steel bars, which are generally oriented horizontally and vertically. The purpose of the reinforcement may be to increase a load-bearing capability of the concrete component, in particular under the influence of tensile stresses. A composite reinforcement may be a special type of reinforcement that in particular is intended to provide a frictional engagement between the concrete semifinished part and the in-situ concrete. 
         [0019]    The end position of the concrete semifinished part in the machine table foundation may be interpreted as the position of the concrete semifinished part assumed by the concrete semifinished part in the finished state of the machine table foundation. 
         [0020]    An end position of the concrete semifinished part in the machine table foundation is logically a position above, in particular over, the at least one pillar by which the table top is supported. 
         [0021]    The in-situ concrete can be poured onto the concrete semifinished part over an entire upper side of the concrete semifinished part or over at least a portion of the upper side. An upper side can be understood to be an upwardly facing side of a component, in particular of the concrete semifinished part. 
         [0022]    The pouring of the in-situ concrete onto the concrete semifinished part may result in the fact that, in particular once the in-situ concrete has cured, an in-situ concrete layer is formed on the upper side or on the at least one portion of the upper side of the concrete semifinished part. The in-situ concrete layer expediently has a thickness that is at least half the thickness of the concrete semifinished part. The thickness of the in-situ concrete layer is advantageously greater than the thickness of the concrete semifinished part. In addition, the thickness of the in-situ concrete layer may be substantially homogenous. 
         [0023]    In the method for producing the machine table foundation, the concrete semifinished part is expediently positioned in its end position in the machine table foundation before the in-situ concrete is poured onto the concrete semifinished part. The concrete semifinished part can be positioned at the construction site, in particular with the aid of a crane. 
         [0024]    The concrete semifinished part can be laid directly onto an upper side of the pillar. Alternatively—in particular if necessary on account of mechanical safety aspects—the concrete semifinished part can be laid onto at least one damping element arranged on the upper side of the pillar. 
         [0025]    A damping element may be an elastically deformable component, in particular a metal component having one or more springs or a component made of plastic or rubber, such as a damping plate. The damping element is advantageously designed for a partial vibratory decoupling of two components, between which the damping element is arranged. 
         [0026]    If the concrete semifinished part is laid directly onto an upper side of the pillar, the concrete semifinished part may have at least one opening. A starter reinforcement comprising reinforcement bars can be guided through this opening. A starter reinforcement may be a special type of reinforcement that is intended in particular to provide a frictional engagement between the pillar and the in-situ concrete and/or between the pillar and the concrete semifinished part. 
         [0027]    The reinforcement bars of the starter reinforcement may be embedded in part in the pillar. The reinforcement bars of the starter reinforcement may also protrude in part from the pillar, in particular from the upper side of the pillar. The reinforcement bars of the starter reinforcement are oriented vertically. By pouring the in-situ concrete onto the concrete semifinished part, the reinforcement bars of the starter reinforcement can be embedded in part in the in-situ concrete. The opening in the concrete semifinished part is advantageously closed by the in-situ concrete by the casting of the in-situ concrete. 
         [0028]    For example, it may then be necessary to arrange at least one damping element between the concrete semifinished part and the pillar when the machine, the load of which is carried by the machine table foundation, operates in a frequency range in which or in the vicinity of which at least a natural frequency of the pillar lies. Whether the machine operates in a frequency range in which or in the vicinity of which at least a natural frequency of the pillar lies may be dependent inter alia on the machine type and/or a geometry of the pillar. By arranging the damping element between the pillar and the concrete semifinished part, vibrations generated by the operating machine and which can be transmitted from the concrete semifinished part to the pillar can be damped to such an extent that a resonance catastrophe at the pillar can be prevented. 
         [0029]    The damping element, on account of the weight of the subsequently placed concrete semifinished part or on account of its own weight, is advantageously secure against a movement relative to the pillar, in particular already before the placement of the concrete semifinished part, due to frictional forces between the damping element and the pillar. 
         [0030]    The damping element, however, may also be fastened to the pillar and/or to the subsequently placed concrete semifinished part, in particular by means of a screwed or bonded connection. Alternatively, the damping element may be embedded in part in the pillar. 
         [0031]    If the table top, for example for reasons of stability, is supported by a plurality of pillars, the concrete semifinished part is advantageously laid onto the upper sides of at least two pillars or onto two or more damping elements, at least two of which are arranged on different pillars. 
         [0032]    A formwork element—or also a plurality of formwork elements—of a formwork for the in-situ concrete is expediently fastened to the concrete semifinished part before the in-situ concrete is poured onto the concrete semifinished part. It is particularly advantageous when the formwork element is fastened to the concrete semifinished part before the concrete semifinished part is positioned in its end position in the machine table foundation, in particular provided the concrete semifinished part is located on the ground. An assembly of the formwork element that can be easily carried out is thus made possible. 
         [0033]    At least one operating floor element of an operating floor is advantageously fastened to the formwork element and/or the concrete semifinished part. An operating floor may be understood to be a platform, in particular constructed in a modular manner, for carrying out work, in particular at a height of a number of meters. The operating floor element is expediently fastened to the formwork element before the in-situ concrete is poured onto the concrete semifinished part, in particular before the concrete semifinished part is positioned in its end position in the machine table foundation. 
         [0034]    The formwork element is logically fastened to the concrete semifinished part only temporarily. Once the in-situ concrete has cured, the formwork element is expediently dismantled. 
         [0035]    A supplementary reinforcement, for example in the form of a grating, comprising reinforcement bars may also be arranged above the concrete semifinished part before the in-situ concrete is poured onto the concrete semifinished part. A supplementary reinforcement may be understood to be a reinforcement arranged outside the concrete semifinished part, which reinforcement may serve to increase the load-bearing capability of the in-situ concrete, in particular under the influence of tensile stresses. 
         [0036]    The concrete semifinished part is advantageously pre-wetted with water before the in-situ concrete is poured, in particular for approximately 24 h. A more extensive integral bond may thus form between the concrete semifinished part and the in-situ concrete, since concrete can form an integral bond more easily in a moist state. The concrete semifinished part is logically pre-wetted directly before the in-situ concrete is poured, for example following the arrangement of the supplementary reinforcement, so that the water is not already evaporated before the in-situ concrete is poured. 
         [0037]    The in-situ concrete is advantageously poured onto a plurality of concrete semifinished parts positioned in their end positions in the machine table foundation. 
         [0038]    The plurality of concrete semifinished parts are logically positioned, in particular at the construction site, in their end positions in the machine table foundation before the in-situ concrete is poured onto the concrete semifinished parts. 
         [0039]    The plurality of concrete semifinished parts are expediently positioned each over at least one pillar, advantageously each over at least two pillars, if the table top is supported by a plurality of pillars. 
         [0040]    The plurality of concrete semifinished parts may be offset from one another in the vertical direction or may be positioned at approximately the same height. The plurality of concrete semifinished parts may also be positioned adjacently at least in pairs, wherein at least two side faces of two adjacently arranged concrete semifinished parts may contact, or a joint may distance the two concrete semifinished parts. A modular structure of a lower portion of the table top supporting the in-situ concrete is thus made possible. In particular, a variable aspect ratio and/or a variable geometry of the table top can be achieved by the modular structure. 
         [0041]    A first concrete semifinished part is advantageously laid in portions (“with partial overlap”) onto a second concrete semifinished part before the in-situ concrete is poured onto the two concrete semifinished parts. 
         [0042]    It is possible that, following the placement on the second concrete semifinished part with partial overlap, the first concrete semifinished part, on account of its own weight, is secure against a movement relative to the second concrete semifinished part, due to frictional forces between the first and the second concrete semifinished part. However, the first and the second concrete semifinished part are advantageously interconnected in a frictionally engaged manner before the in-situ concrete is poured onto the two concrete semifinished parts. In particular, contact plates can be fastened to the first and the second concrete semifinished part, which contact plates are welded to one another. Alternatively, the first and the second concrete semifinished part can be screwed to one another. The same is also true for two adjacently arranged concrete semifinished parts not arranged with partial overlap. 
         [0043]    The second concrete semifinished part may already be positioned in its end position in the machine table foundation when the first concrete semifinished part is laid on the second concrete semifinished part with partial overlap. Alternatively, the first concrete semifinished part whilst still on the ground can be laid on the second concrete semifinished part with partial overlap. If the two concrete semifinished parts are interconnected in a frictionally engaged manner, they can be jointly positioned from the ground in their end positions in the machine table foundation. 
         [0044]    A space, in particular a gap, between two adjacent formwork elements that can be fastened to the same concrete semifinished parts or to different concrete semifinished parts is expediently covered by an additional formwork element before the in-situ concrete is cast. The in-situ concrete can thus be prevented from flowing out through the space between the two formwork elements. The additional formwork element for covering the space between the two adjacent formwork elements is advantageously fastened to said formwork elements. 
         [0045]    Mortar is advantageously introduced into a space, in particular a joint, between two adjacent concrete semifinished parts before in-situ concrete is poured onto these two semifinished parts. The space or the joint between the two adjacent concrete semifinished parts can thus be closed, such that the in-situ concrete can be prevented from flowing out, in particular downwardly, through the space or through the joint. Alternatively, instead of the mortar, expanding foam or another sealant can be introduced into the space or the joint between the two adjacent concrete semifinished parts. 
         [0046]    Furthermore, mutually opposed formwork elements, which can be fastened to the same concrete semifinished part or to different concrete semifinished parts, can be prestressed by at least one tensioning anchor before the in-situ concrete is cast. 
         [0047]    A tensioning anchor may be understood to mean a device that serves to compensate for compressive forces potentially exerted onto the formwork elements by the in-situ concrete, in particular still in the uncured state. The tensioning anchor may comprise one or more wires (“tensioning wires”). The tensioning wire or the tensioning wires advantageously consists/consist substantially of steel. An anchoring plate may be fastened to different ends of the tensioning wire or the tension wires, said anchoring plates possibly bearing against an outer face of one of the mutually opposed formwork elements. 
         [0048]    The side of the formwork element facing away from the in-situ concrete may be understood to be the outer side of the formwork element. 
         [0049]    The tensioning anchor may be surrounded in portions by an enveloping tube. In particular the tensioning wire or the tensioning wires of the tensioning anchors may be surrounded by the enveloping tube between the mutually opposed formwork elements prestressed by the tensioning anchor. 
         [0050]    The tensioning anchor is logically dismantled before the formwork elements are dismantled, but after the in-situ concrete has cured. The enveloping tube may remain in the cured in-situ concrete. The tensioning anchor is advantageously pulled out from the in-situ concrete through the enveloping tube. 
         [0051]    Once the in-situ concrete has cured at least one concrete element can be cast on the table top, in particular on an upper side of the in-situ concrete. The concrete element may be, in particular, a substructure for at least one machine element of a machine for which the machine table foundation is intended. 
         [0052]    Before the concrete element is cast, an additional formwork is logically arranged on the table top, in particular on the upper side of the in-situ concrete. The additional formwork is expediently fastened to the table top or to the in-situ concrete of the table top. 
         [0053]    In order to reinforce the concrete element, an additional reinforcement may be arranged within the additional formwork or the additional formwork may be arranged around the additional reinforcement arranged on the table top. Alternatively, the additional formwork may be arranged around a reinforcement that is embedded in portions in the table top and protrudes in portions from the table top. 
         [0054]    The at least one pillar carrying the table top is advantageously vertically oriented. For reasons of stability the pillar may be embedded in portions in a subsurface. The pillar advantageously has a planar upper side. The upper side of the pillar is expediently horizontally oriented. The concrete semifinished part can thus rest horizontally on the pillar. 
         [0055]    In the machine table foundation, the table top is expediently horizontally oriented. The table top may also be cuboidal. 
         [0056]    The concrete semifinished part is advantageously arranged above, in particular over, the pillar. 
         [0057]    The concrete semifinished part may rest directly on an upper side of the pillar. Alternatively, the concrete semifinished part may rest on at least one damping element arranged on the upper side of the pillar. The damping element may be fastened to the pillar and/or the concrete semifinished part, in particular by means of a screwed or bonded connection. However, the damping element may also be embedded in part in the pillar. 
         [0058]    If the concrete semifinished part rests directly on an upper side of the pillar, the concrete semifinished part advantageously has at least one opening. A starter reinforcement comprising reinforcement bars can be guided through this opening. 
         [0059]    The reinforcement bars of the starter reinforcement may be embedded in part in the pillar. The reinforcement bars of the starter reinforcement may also be embedded in part in the in-situ concrete. Reinforcement bars of the starter reinforcement are advantageously vertically oriented. The opening in the concrete semifinished part is advantageously closed by in-situ concrete. 
         [0060]    A composite reinforcement comprising reinforcement bars is advantageously embedded in the table top. The reinforcement bars of the composite reinforcement are expediently embedded in portions in a concrete body of the concrete semifinished part. It is also expedient when the reinforcement bars of the composite reinforcement are also embedded in portions in the in-situ concrete. A frictional engagement between the in-situ concrete and the concrete semifinished part is thus made possible. The composite reinforcement may be embedded completely in the table top. However, it may also protrude from the table top. 
         [0061]    The reinforcement bars of the composite reinforcement are expediently embedded ex factory in the concrete body of the concrete semifinished part. Some or all of the reinforcement bars of the composite reinforcement are advantageously substantially vertically oriented. Furthermore, a further reinforcement comprising reinforcement bars may be embedded in the concrete semifinished part, wherein the reinforcement bars of the further reinforcement may be embedded in particular completely in the concrete body of the concrete semifinished part. The further reinforcement bars can be used to increase the load-bearing capability of the concrete semifinished part, in particular under the influence of tensile stresses. 
         [0062]    It is advantageous when a supplementary reinforcement comprising reinforcement bars is embedded in the table top. The reinforcement bars of the supplementary reinforcement may be arranged exclusively outside the concrete semifinished part. The reinforcement bars of the supplementary reinforcement are logically embedded in the in-situ concrete. The reinforcement bars of the supplementary reinforcement may serve to increase the load-bearing capability of the in-situ concrete, in particular under the influence of tensile stresses. 
         [0063]    It is also advantageous when at least one threaded sleeve is embedded in the concrete semifinished part. The threaded sleeve expediently has an accessible threaded opening. It is advantageously possible by means of the threaded sleeve to fasten a formwork element to the concrete semifinished part. Alternatively, functionally similar fastening elements can be provided. 
         [0064]    The concrete semifinished part may have a profiled upper side, for example a rough, upper side. The profiled upper side of the concrete semifinished part may promote a frictional engagement between the concrete semifinished part and the in-situ concrete. 
         [0065]    The table top may comprise a plurality of concrete semifinished parts. The in-situ concrete is logically poured onto the plurality of concrete semifinished parts. 
         [0066]    The plurality of concrete semifinished parts are expediently arranged each over at least one pillar, advantageously each over at least two pillars, if the machine table foundation has a table top supported by a plurality of pillars. 
         [0067]    The plurality of concrete semifinished parts may be offset from one another in the vertical direction or may be positioned at approximately the same height. The plurality of concrete semifinished parts may also be positioned adjacently at least in pairs, wherein at least two side faces of two adjacently arranged concrete semifinished parts may contact, or a joint may distance the two concrete semifinished parts. 
         [0068]    If two adjacently arranged concrete semifinished parts are distanced by a joint, the joint is advantageously sealed off by means of a sealant with respect to an outflow of the in-situ concrete. In particular the sealant may be mortar or expanding foam. 
         [0069]    The concrete semifinished parts may have profiled, in particular rough, side faces. A greater stability of the table top of the machine table foundation can thus be achieved. 
         [0070]    A first concrete semifinished part advantageously rests in portions (with partial overlap) on a second concrete semifinished part. 
         [0071]    The first concrete semifinished part may have at least one stepped bearing. The second concrete semifinished part may have at least one bracket. The first concrete semifinished part expediently rests via its stepped bearing on the bracket of the second concrete semifinished part. 
         [0072]    A bracket may be understood to mean a protrusion of a component, which protrusion is designed to support a load, in particular of another component. A stepped bearing may be understood to mean a protrusion of a component, which protrusion is designed to lie on a bracket. 
         [0073]    The stepped bearing of the first concrete semifinished part may have the same length as the bracket of the second concrete semifinished part. A reinforcement may be embedded in the bracket and/or in the bearing. 
         [0074]    Furthermore, the first and the second concrete semifinished part may be interconnected in a frictionally engaged manner. In particular, contact plates can be fastened to the first and to the second concrete semifinished part, which contact plates are welded to one another. Alternatively, the first and the second concrete semifinished part can be screwed to one another. 
         [0075]    At least one concrete element cast with additional in-situ concrete can be arranged on the table top, in particular on an upper side of the in-situ concrete. The concrete element may be, in particular, a substructure for at least one machine element of a machine for which the machine table foundation is intended. 
         [0076]    With regard to the use of the concrete semifinished part, the concrete semifinished part is expediently used as a component of the table top of the machine table foundation supporting in-situ concrete. 
         [0077]    The above description of advantageous embodiments contains numerous features which are presented, in part in multiple combination, in the individual dependent claims. However, these features may also be considered individually and may be combined in sensible further combinations. In particular, these features can be combined individually and in any suitable combination with the method according to the invention, the machine table foundation according to the invention, and the use according to the invention according to the independent claims. 
         [0078]    The above-described properties, features and advantages of this invention, as well as the way in which these are achieved, will be understood more clearly and concisely in conjunction with the following description of the exemplary embodiment, which will be explained in greater detail in conjunction with the drawings. The exemplary embodiment serves to explain the invention and does not limit the invention to the combination of features specified therein, including in respect of functional features. In addition, features of the exemplary embodiment suitable for this purpose may also be considered explicitly in isolation and combined with any one of the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0079]    In the drawings: 
           [0080]      FIGS. 1-7  show an oblique view from above of different states of construction of a machine table foundation during production thereof, 
           [0081]      FIG. 8  shows a cross section through a table top, and 
           [0082]      FIG. 9  shows a concrete semifinished part with a bracket and a concrete semifinished part with a stepped bearing in cross section. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0083]      FIGS. 1 to 7  show an oblique view from above of different states of construction of a machine table foundation for a turbine unit during production of said machine table foundation. The states of construction illustrated in the figures are arranged in accordance with increasing construction progress. For the sake of clarity, the turbine unit is absent from the figures. 
         [0084]    In  FIG. 1  six pillars  2  are illustrated. The pillars  2  are vertically oriented. The upper sides  4  of the pillars  2  are planar and additionally horizontally oriented. The pillars  2  are also arranged in such a way that their upper sides  4  lie in one plane. 
         [0085]    Two metal damping elements  6  are arranged on the upper sides  4  of each of the pillars  2 , wherein the damping elements comprise a plurality of springs and are fastened by means of screwed connections to the respective pillars  2 . Damping elements  6  serve for the partial vibratory decoupling of the pillars  2  from components laid subsequently onto the pillars  2 . 
         [0086]    The upper sides of the pillars  2  span a rectangle having a longitudinal direction  8  and a transverse direction  10 . In the longitudinal direction  8 , two rows of pillars are arranged with three pillars  2  in each row, and in the transverse direction  10  three rows are arranged with two pillars  2  in each row. 
         [0087]    Formwork elements of a formwork having operating floor elements of an operating floor are firstly fastened to concrete semifinished parts, in particular provided the concrete semifinished parts are located on the ground. The concrete semifinished parts are then positioned in their end positions in the machine table foundation, in particular over the pillars. Here, the concrete semifinished parts are laid onto the damping elements fastened to the pillars. 
         [0088]    In  FIG. 2  three concrete semifinished parts  12  are in each case arranged over two of the six pillars  2 . The concrete semifinished parts  12  rest on the damping elements  6  of the pillars  2  and are located in their end positions in the machine table foundation. 
         [0089]    Furthermore, each of the three concrete semifinished parts is provided with a composite reinforcement  16  comprising reinforcement bars  14 . The reinforcement bars  14  of the composite reinforcement  16  are embedded in portions in a concrete body  18  of the respective concrete semifinished parts  12 . The reinforcement bars  14  of the composite reinforcement  16  also protrude in portions from the concrete body  18  of the respective concrete semifinished parts  12 . In addition, the reinforcement bars  14  of the composite reinforcement  16  are vertically oriented. 
         [0090]    The composite reinforcement  16  serves to produce a frictional engagement between the concrete semifinished parts  12  and an in-situ concrete poured subsequently onto the concrete semifinished parts  12  and also to increase the load-bearing capability of the in-situ concrete, in particular under the influence of tensile stresses. 
         [0091]    Four vertically oriented formwork elements  20 , each having their own operating floor element  22 , are fastened to the left concrete semifinished part  12 —as seen by the viewer. Four vertically oriented formwork elements  20  are fastened to the right concrete semifinished part  12 , wherein an operating floor element  22  is fastened to three of these four formwork elements  20 . Three vertically oriented formwork elements  20  each having their own operating floor element  22  are fastened to the middle concrete semifinished part  12 . 
         [0092]    In each of the three concrete semifinished parts  12 , there are embedded a plurality of threaded sleeves, which each have an accessible threaded opening. The formwork elements  20  are fastened to the concrete semifinished parts  12  with the aid of the threaded sleeves. For the sake of clarity, the threaded sleeves are not illustrated in  FIG. 2 . A cross section of a concrete semifinished part, in which the embedded threaded sleeves can be seen, is illustrated in  FIG. 8 . 
         [0093]    Furthermore, all three concrete semifinished parts  12  have the same width, the same thickness and the same length. The thickness of the concrete semifinished parts  12  is approximately 0.5 m. Their length is approximately 13 m, and their width is approximately 2.5 m. 
         [0094]    The three concrete semifinished parts  12  are oriented along the transverse direction  10 . Consequently, the three concrete semifinished parts  12  are also referred to as transverse beams. 
         [0095]    In the following step of a construction phase, further concrete semifinished parts are positioned in their end positions in the machine table foundation, and in particular are laid onto the concrete semifinished parts  12  previously positioned over the pillars  2 . In addition, the further concrete semifinished parts are connected in a frictionally engaged manner to the concrete semifinished parts  12  positioned previously over the pillars  2 . 
         [0096]    Four further concrete semifinished parts  24  above the three concrete semifinished parts  12  positioned previously over the pillars  2  are illustrated in  FIG. 3 . Two of the four further concrete semifinished parts  24  have a width of approximately 3.5 m. The other two of the four further concrete semifinished parts  24  have a width of approximately 2 m. 
         [0097]    The four further concrete semifinished parts  24  are oriented along the longitudinal direction. Consequently, the four further concrete semifinished parts  24  are also referred to as longitudinal beams. The four longitudinal beams are each provided with a composite reinforcement  16 , in exactly the same way as the three transverse beams. 
         [0098]    Two vertically oriented formwork elements  20  each having their own operating floor element  22  are fastened to the two narrower of the four longitudinal beams. A vertically oriented formwork element  20  having an operating floor element  22  is fastened to each of the two wider of the four longitudinal beams. 
         [0099]    A plurality of threaded sleeves are embedded in each of the four longitudinal beams—in exactly the same way as in the transverse beams—and said threaded sleeves each have an accessible threaded opening. The formwork elements  20  are fastened to the longitudinal beams with the aid of the threaded sleeves. The threaded sleeves are not illustrated in  FIG. 3 , for the sake of clarity. 
         [0100]    The two wider longitudinal beams are interconnected by two steel girders  26  oriented parallel to one another. Each of the two steel girders  26  is embedded at one of its two ends in one of the two wider longitudinal beams and at the other of its two ends in the other of the two wider longitudinal beams. The two steel girders  26  are also exposed in portions. In a region in which the steel girders  26  are embedded, the two wider longitudinal beams have a second portion  28 . 
         [0101]    In  FIG. 4  the four longitudinal beams from  FIG. 3  are laid in portions on the three transverse beams positioned previously on the pillars  2 . 
         [0102]    Here, the two narrower longitudinal beams are each laid on the left and on the middle transverse beams and the two wider longitudinal beams are each laid on the middle and the right transverse beams. 
         [0103]    The left and the right transverse beams each have two brackets. The middle transverse beam has four brackets. In addition, the longitudinal beams each have two stepped bearings. The longitudinal beams are laid via their stepped bearings onto the brackets of the transverse beams. In addition, the longitudinal beams are connected in a frictionally engaged manner, in particular screwed, to the longitudinal beams. For the sake of clarity, the brackets of the transverse beams and the stepped bearings of the longitudinal beams are absent in  FIG. 4 . A bracket of a concrete semifinished part  12 , in particular of a transverse beam, and a stepped bearing of another concrete semifinished part  24 , in particular of a longitudinal beam, are illustrated in cross section in  FIG. 9 . 
         [0104]    The longitudinal beams and the transverse beams are also arranged at approximately the same height. Longitudinal beams and transverse beams arranged adjacently in pairs are each distanced from one another by a joint. 
         [0105]    In the next step of the construction phase additional concrete semifinished parts are positioned in their end positions in the machine table foundation, and in particular are laid onto the further concrete semifinished parts  24 . 
         [0106]    In  FIG. 5  four additional concrete semifinished parts  30  rest on the two wider longitudinal beams. Two of the four additional concrete semifinished parts  30  are oriented along the longitudinal direction  8  and rest with partial overlap on each of the two wider transverse beams. The other two of the four additional concrete semifinished parts  30  are oriented along the transverse direction  10  and each rest on the second portion  28  of one of the two wider transverse beams respectively. 
         [0107]    The four additional concrete semifinished parts  30  are arranged offset from the transverse and longitudinal beams in the vertical direction. 
         [0108]    The four additional concrete semifinished parts  30  are also connected in a frictionally engaged manner, in particular are screwed, to the transverse beams. In addition, the additional concrete semifinished parts  30  are each provided with a composite reinforcement  16 , in exactly the same way as the three transverse beams and the four longitudinal beams. 
         [0109]    In the next step of the construction phase, gaps between adjacent formwork elements  20  are covered by additional formwork elements, which are fastened to the previously mounted formwork elements. In addition, mortar is introduced into joints between the concrete semifinished parts, and mutually opposed formwork elements  20  are prestressed by means of tensioning anchors. 
         [0110]    In  FIG. 6 , gaps between adjacent formwork elements  20  are covered by additional formwork elements  32 , which are fastened to the previously mounted formwork elements  20 . 
         [0111]    Furthermore, further operating floor elements  34  are fastened to the previously mounted operating floor element  22 , such that a fully accessible operating floor is created. 
         [0112]    In addition, further formwork elements  35  are fastened to the additional concrete semifinished parts  30 , which rest on two of the transverse beams. 
         [0113]    Mutually opposed formwork elements  20  are prestressed using tensioning anchors, wherein the tensioning anchors are arranged merely between inner sides of the formwork elements, wherein an inner side of a formwork element is to be understood to mean the side that subsequently comes into contact with the in-situ concrete cast. For the sake of clarity, the tensioning anchors are absent in  FIG. 6 . A cross section of a table top, in which the tensioning anchors can be seen, is illustrated in  FIG. 8 . 
         [0114]    A supplementary reinforcement is next arranged over all concrete semifinished parts. The concrete semifinished parts are then pre-wetted with water. The in-situ concrete is then poured onto the concrete semifinished parts, whereby a table top of the machine table foundation consisting of the concrete semifinished parts and the in-situ concrete is completed. Once the in-situ concrete of the table top has cured, additional formworks are arranged on the upper side of the in-situ concrete, and concrete elements are cast. 
         [0115]    The finished machine table foundation  38  is illustrated in  FIG. 7 , wherein the formwork for the table top  40  has not yet been dismantled. The concrete semifinished parts can no longer be seen, since these are hidden by the in-situ concrete  42 . 
         [0116]    The table top  40  has two rectangular, clear openings. The left opening  44 —as seen by the viewer—serves as access to an apparatus arranged beneath the table top  40 , in particular a condenser. The right opening  46  serves to pass through an electrical connector of a generator connection. 
         [0117]    Two concrete elements  48  cast with additional in-situ concrete and which serve as substructure for a machine element of the turbine unit are also located on the table top  40 . 
         [0118]    In addition, a plane of section  49  is indicated. The cross section illustrated in  FIG. 8  through the table top  40  is a section through this plane of section  49 . 
         [0119]    All of the concrete semifinished parts illustrated in  FIGS. 1 to 7  are also provided, in addition to the composite reinforcement  16 , with a further reinforcement  64  comprising reinforcement bars  62 . The reinforcement bars  62  of this further reinforcement  64  are embedded completely in the concrete body  18  of the respective concrete semifinished part and consequently cannot be seen in  FIGS. 1 to 7 . 
         [0120]    Furthermore, each of the concrete semifinished parts illustrated in  FIGS. 1 to 7  has a profiled upper side  50 , which can promote a frictional engagement between the respective concrete semifinished part and the in-situ concrete  42 . In addition, each of the concrete semifinished parts illustrated in  FIGS. 1 to 7  has at least one profiled side face, whereby a greater stability of the table top can be achieved. 
         [0121]      FIG. 8  illustrates a cross section through the table top  40 , in particular a section along the plane of section  49  indicated in  FIG. 7 . 
         [0122]    The concrete semifinished part  12  with its profiled upper side  50  and the in-situ concrete  42  poured onto the concrete semifinished part can be seen. 
         [0123]    A formwork element  20  is fastened to a left side—as seen by the viewer—and to a right side of the concrete semifinished part  12 . The two formwork elements  20  are each fastened to the concrete semifinished part  12  with the aid of two threaded sleeves  52 , which are embedded in the concrete semifinished part  12 . An operating floor element  22  is also fastened to each of the two formwork elements  20 . 
         [0124]    Furthermore, two tensioning anchors  54  are fastened to the two formwork elements  20 . Here, the two tensioning anchors  54  are each fastened at one of their two ends to the left formwork element  20  and at the other of their two ends to the right formwork element  20 . Between formwork elements  20 , the tensioning anchors  54  are each surrounded completely by an enveloping tube  56 . The two tensioning anchors  54  serve to compensate for compressive forces potentially exerted onto the formwork elements  20  by the in-situ concrete  42 , in particular before the in-situ concrete has cured. 
         [0125]    Horizontally oriented reinforcement bars  58  of the supplementary reinforcement  60 , which are fully embedded in the in-situ concrete  42 , and horizontally oriented reinforcement bars  62  of the further reinforcement  64 , which are fully embedded in the concrete semifinished part  12 , can be seen. In addition, vertically oriented reinforcement bars  14  of the composite reinforcement  16  can be seen, which are fully embedded in the table top  40  and here are embedded in portions in the concrete body  18  of the concrete semifinished part  12  and are also embedded in portions in the in-situ concrete  42 . 
         [0126]    At their upper and lower ends, the reinforcement bars  14  of the composite reinforcement  16  are interconnected by metal arches  66  (“stirrups”). The reinforcement bars  58  of the supplementary reinforcement  60  and the reinforcement bars  62  of the further reinforcement  64  are interconnected at their ends likewise by metal arches, however this is not visible since the illustrated view is a vertical cross section. 
         [0127]    In  FIG. 9  two concrete semifinished parts are illustrated in cross section. The left concrete semifinished part  12 —as seen by the viewer—is a transverse beam in particular. The right concrete semifinished part  24  is a longitudinal beam in particular. 
         [0128]    The transverse beam has a bracket  68 , whereas the longitudinal beam has a stepped bearing  70 . The bracket  68  and the stepped bearing  70  have substantially the same dimensions. The longitudinal beam is laid via its stepped bearing  70  onto the bracket  68  of the transverse bearing. So that the bracket  68  and the stepped bearing  70  can be better seen, the two concrete semifinished parts are illustrated in  FIG. 9  offset from one another in the horizontal and vertical direction. 
         [0129]    A metal contact plate  72  is fastened to each of the two concrete semifinished parts. The contact plates  72  are welded to one another in order to produce a frictionally engaged connection between the two concrete semifinished parts. 
         [0130]    The two concrete semifinished parts have a composite reinforcement  16  with vertically oriented reinforcement bars  14  and a further reinforcement  64  with horizontally oriented reinforcement bars  62 . The reinforcement bars  62  of the further reinforcement  64  are fully embedded in the concrete body  18  of the respective concrete semifinished part, whereas the reinforcement bars  14  of the composite reinforcement  16  are embedded in portions in the concrete body  18  in question and also protrude in portions from the concrete body  18 . 
         [0131]    At their lower ends, the reinforcement bars  14  of the composite reinforcement  16  are interconnected by metal arches  66 . Part of the further reinforcement  64  of the respective concrete semifinished part is also embedded in the bracket  68  and/or in the stepped bearing  70 . 
         [0132]    Although the invention has been illustrated and described in greater detail by the preferred exemplary embodiment, the invention is not limited by the disclosed examples, and other variations can also be derived herefrom without departing from the scope of protection of the invention.