DE102012219209A1 - Wall element for prefabricated buildings - Google Patents

Abstract

The aim is to create a modular, prefabricated, solid reinforced concrete structure made of reinforced concrete slabs and joint connecting elements, which after connecting the individual elements as a monolithic unit will support the high load level under various load cases, as is typical in nuclear power plant construction. This is achieved by means of a wall element (2) designed as a prefabricated concrete component for erecting a building with a wall body which has an essentially rectangular base area and four edges and which, in the manner of a sandwich construction, has an inner shell (4), an outer shell (6) and an intermediate core filling (8), whereby • the inner shell (4) is made of reinforced concrete and has a main reinforcement (18) consisting of a total of lattice-shaped horizontal reinforcement bars (20) and vertical reinforcement bars (22) which run parallel to the edges and which the inner shell ( 4) each penetrate essentially from edge to edge, • the vertical reinforcement bars (22) are provided at their ends with connecting elements (10), which are used to produce a screw or tension connection with complementary connecting elements (10) of a wall element above or below ( 2) are formed, • a plurality of each s there are U-brackets (44) which are angled at right angles and have a leg end (46) and a bow end (48) and are cast with their leg end (46) into the inner shell (4), the respective U-bracket (44) in the area of the bend (52) engages around one of the vertical reinforcing bars (22) and protrudes with its arch end (48) into the core filling (8), and • the outer shell (6) is constructed analogously to the inner shell (4).

Description

The invention relates to a trained as precast concrete wall element for the construction of a building. It further relates to a construction made using such wall elements, in particular an operating or plant building of a nuclear power plant.

Safety-related buildings of nuclear facilities, such as those buildings that house the emergency generators, have so far been almost exclusively designed as a local concrete construction. Due to the very high load level, the prefabricated construction method tested in ordinary residential construction has so far not been used in the nuclear sector.

The building / construction must withstand all the loads and load connections of the following events from the groups EVI - influence of indoor and external EVA:

Normal operation:

• - Permanent loads
• - Variable loads including loads due to transport and installation
• - Combined loads

Influences caused by outside events:

• - explosion
• - crashes of flying machines
• - Fire in the outdoor area

Influences from internal unforeseen events:

• - Internal fire
• - collapse of the inner design
• - Falling loads
• - Internal flooding
• - Internal explosion

Unlikely events:

• - Earthquake
• - Extreme winds
• - Extreme snow and icing
• - Tornadolasten, influence of Tornado-Geschossen
• - Extreme outside temperatures
• - External flooding
• - extreme precipitation
• - Property protection
• - Explosive pressure wave
• - Explosive gas cloud

The use of prefabricated components - although considered to be quite desirable because of the associated standardization and the optimization of the entire planning, construction and construction processes - encountered considerable difficulties in this context and was therefore omitted. This is particularly due to the customary in prefabrication connection technologies that either do not meet the requirements imposed in the nuclear sector in terms of load transfer or are not able to comply with the there encountered allowable component tolerances and at the same time allow flexible connections on site and alignment inaccuracies in the Overcome assembly.

The fact that essentially the same buildings, with the same functionality are planned for each nuclear power plant, leads to the consideration of how the planning and execution costs can be reduced.

A reduction is possible by means of systems which make it possible to flexibly plan the desired rooms and their occupancy with prefabricated modules. This is based on the consideration that the introduction of prefabricated construction previously encountered mainly difficulties with respect to the frictional connection between the individual components and overcoming the associated tolerances and dimensional inaccuracies and alignment inaccuracies in the assembly.

In a pre-announcement of the AREVA NP GmbH with the publication number WO 2012/123067 A1 a wall element of the type mentioned was disclosed, which can be easily combined with other such wall elements to a building, especially a building or complex of buildings, and connect, which is designed not only for ordinary operating loads, but also unlikely extreme loads - individually or even in combination - such as flooding, earthquakes, continuous rain, ice loads, wind loads, hurricanes, extreme ambient temperatures, impact of projectiles, plane crashes, etc.

Accordingly, designed as a precast concrete wall element - there called wall module - provided for the construction of a structure with a wall body, with a plurality of in their entirety a regular reinforcing grid forming, preferably each parallel to the edges of the wall body extending reinforcing bars which are cast into the wall body , wherein at least some of the reinforcing bars penetrate the wall body in each case substantially from edge to edge and are provided at their ends with connecting elements which are used for the production a connection with complementary connecting elements of an immediately adjacent conversion element are formed. In this case, the respective connecting element - at least in the dissolved, not connected to a complementary connecting element state - so playfully connected or movably connected to the associated reinforcing rod that it is displaceable in a direction perpendicular to the longitudinal direction of the reinforcing rod level on all sides by at least 2 millimeters relative to an intended central position ,

Furthermore, a wall element has been described as a preferred embodiment in which the wall body has a shell, an inner shell and an intermediate core filling in the manner of a sandwich construction, wherein the outer shell and the inner shell via reinforcing elements are thrust and tensile strength connected to each other. However, this basic concept of the sandwich construction was not specified there in detail with regard to possible embodiments.

At this point, the present invention begins, whose task is to further develop the wall elements described in the above-mentioned application. It is a modular prefabricated solid reinforced concrete construction of reinforced concrete slabs and joints joints arise that removes the high load level of the various load cases mentioned above after connecting the individual elements as a monolithic unit. In particular, it is intended to create a reinforcing structure for the reinforced concrete slabs and for the joint joints that can be erected with acceptable effort and designed for the stated requirements. In addition, the existing when juxtaposing the wall elements and with cast-in-situ or other filling material - for example mortar - to be potted joints have the lowest possible volume, so that on site only little in situ concrete and formwork material is needed.

This object is achieved by the features of claim 1.

Advantageous developments and concretizations of the basic principle will become apparent from the subclaims and from the following detailed description of an embodiment. Each shows in a simplified and schematic representation:

1 a manufactured in sandwich wall element with an inner shell, an outer shell and a core filling in perspective view,

2 the structure of the reinforcement of the inner shell of the wall element in an intermediate stage during production in perspective view,

3 a longitudinal section through the wall element,

4 a section from 3 .

5 the structure of the reinforcement of the inner shell of the wall element before casting the concrete mass surrounding the reinforcement in a perspective view,

6 the inner shell of the wall element after pouring the concrete mass in perspective view,

7 the connection between the inner shell and the outer shell of the wall element in perspective view,

8th the connection between the inner shell and the outer shell of the wall element in a perspective view, wherein the concrete mass of the outer shell was graphically hidden (or made transparent),

9 a top view of the connection between the inner shell and the outer shell of the wall element,

10 from top to bottom different intermediate stages in the connection of two adjacently placed wall elements in each perspective view,

11 another intermediate stage in the connection of two juxtaposed wall elements, namely when casting the vertical butt joint between the two wall elements,

12 a section of in 2 shown reinforcement in lateral plan view,

13 a detail of the joint reinforcement in the vertical butt joint of two juxtaposed wall elements in perspective view,

14 a cross section through the connecting region of two superimposed wall elements, and

15 a longitudinal section through the connecting region of two superimposed wall elements.

In the following, all position and direction indications refer to as "top", "bottom", "vertical", "Horizontal", etc. on the illustrated in the figures usual installation position of the wall elements.

1 shows a perspective view of a manufactured in sandwich construction cuboid wall element 2 For example, for use in a nuclear power plant building. The intended for arrangement in a side wall of a building wall and usually forming a complete floor height wall element 2 has an inner shell constructed as a reinforced concrete structure 4 , a corresponding outer shell 6 and an intermediate core filling 8th , for example, from heavy concrete, on. The inner shell 4 and the outer shell 6 are each approximately mirror images of each other in an otherwise similar manner, as will be described in more detail below. At the top, stick out of the outer shell 4 and from the inner shell 6 several fasteners 10 for the formation of screw to the overlying wall element (not visible here) out. At the (here hidden) bottom of the wall element 2 Functionally complementary connecting elements are arranged in a corresponding manner. In addition, below are in the area of the respective front surface 12 the inner shell 4 and the outer shell 6 engagement openings 14 to accomplish the screwing in the assembly of the wall element system available. The intervention openings 14 enforce each in the manner of a channel the cross section of the inner shell 4 or the outer shell 6 , Reinforcement loops / U-shaped brackets, U-bolts for short, protrude from the two lateral edges 16 , with her bow end from the inner shell 4 and the outer shell 6 of the wall element 2 out, which are provided to form the connections to adjacent wall elements (not visible here).

2 illustrates the construction of the inner shell 4 of the wall element 2 in a sense, in a first phase, during the construction of the inner reinforcing cage, even before the casting of the concrete. The wall element next to it on the right side, as well as the partially potted gap, are indispensable for a while (they are available for image generation with the aid of a CAD program, whereby individual layers have been selectively masked out of the complete construction). The outer shell 6 is as already mentioned analogous to the inner shell 4 built up.

Also referred to as bending reinforcement, for receiving and transmitting tensile forces in the composite wall elements 2 designed main reinforcement 18 includes a in the plane of extension of the wall element 2 horizontal rectangular grid of horizontal reinforcing bars 20 (in 2 only the bottom two are shown) and vertical reinforcing bars 22 , which touch each other at the crossing points where they are braided for example with wire and thus fixed against each other. The horizontal and thus parallel to the upper and lower edge edge of the wall element 2 aligned reinforcing bars 20 are arranged equidistant from each other, as well as the vertical and thus parallel to the side edges of the wall element 2 aligned reinforcing bars 22 , The rod diameter is in both cases - horizontal and vertical - preferably about 30 to 35 mm. The distance between the longitudinal axes of the reinforcing bars 20 . 22 is in both cases preferably around 200 mm (square grid).

Two each in the horizontal direction consecutive, each provided at their upper ends with a screw threaded vertical reinforcing rods 22 are in associated receptacles of a connector 24 screwed, alternatively welded in it. In an intermediate central receptacle of the connector 24 is an upwardly out of the grid composite protruding, also provided with an external thread connecting bolt 26 screwed. On the vertically aligned connection bolts 26 can be from above a provided with a central recess retaining plate 28 postpone it and a mother about it 30 Screw. At the lower end of the pair of rods connected in this way is a box composed of four welded together steel plates or alternatively cast in one piece, rectangular in cross-section box 32 (Box) made of steel, which fits exactly between the two vertical reinforcing bars 22 arranged and welded to them on the outside, alternatively screwed. The arrangement of the connectors 24 and the boxes 32 is chosen so that they later flush the concrete mass flush with the upper or lower edge of the inner shell 4 complete, leaving only the upper part of the connecting bolt 26 sticking out above. Further, the boxes are 32 embedded in the concrete such that the cuboid interior of the respective box 32 and a substantially cuboid mounting space immediately above it remains free. The so formed in each case, coherent cavity is on the one hand from below on the remaining free box opening as well as from the front 12 via the likewise free engaging opening 14 accessible (see also 1 ).

This is a total of a system of fasteners 10 trained, with the help of which in the later assembly of the building superimposed wall elements 2 screw down. This is the upper wall element 2 so on the underlying wall element 2 discontinued, that the upper ends of the connecting bolts 26 of the lower wall element 2 in each case the assigned boxes 32 of the counterpart. Subsequently, through the intervention openings 14 in the front 14 the inner shell 4 (and analogous to the outer shell 6 ) the holding plates 28 which the boxes 32 At the upper edges laterally overlap, on the ends of the connecting bolt 26 pushed on and by screwing and tightening the nuts 30 secured / braced. The holding plates 28 to a certain extent take on the function of washers. The cross section of the boxes 32 is chosen so that the respective connecting bolt 26 It has a few millimeters of play during assembly in all directions, so as to compensate for any inaccuracies in the subsequent assembly on the construction site. This corresponds to that already in the international publication WO 2012/123067 A1 AREVA NP GmbH described the design philosophy. It should be noted that in 1 and 2 Although the sake of clarity, the holding plates 28 and the nuts 30 in its final assembly position on the connecting bolt 26 are shown that in reality but only after the erection of the walls and the joining of the respective connection partners are attached and screwed there.

Back to the construction of the inner shell 4 according to 2 , Except the main reinforcement 18 is still a surface reinforcement 34 , also in the form of intersecting, grid-like arranged reinforcing rods 36 . 38 with a diameter of about 100 mm and with the same mesh size as the main grid (square grid with a bar spacing of about 200 mm). That from the horizontal reinforcing bars 36 and the vertical reinforcing bars 38 formed grid of surface reinforcement 34 is parallel to the lattice of the main reinforcement 18 arranged, and at a distance in the direction of the (here rear) front 14 the inner shell 4 , In the lateral direction, the crossing points of the two reinforcing meshes are preferably offset by half a mesh length. The crossing points of the surface reinforcement 34 So lie in the center of the mesh of the main reinforcement 18 and vice versa (see also 12 ).

Furthermore, at the side edges of the inner shell 4 as already mentioned outwardly projecting U-bracket 16 or steel (reinforcement) loops for later training and fixation of the lateral wall element joints attached. The individual U-bolts 16 have two horizontally and parallel to the longitudinal direction of the subsequent wall element 2 running thighs 40 on, in the space between the main reinforcement 18 and the surface reinforcement 34 lie and prefers the vertical reinforcing bars 22 the main reinforcement 18 touch (at the points of contact are braided together with wire), on the side on which also the horizontal reinforcing bars 20 are arranged. The one leg 40 of the respective U-bracket 16 lies above the associated horizontal reinforcing bar 20 the main reinforcement 18 , the other below. In other words, each of the horizontal reinforcing bars lies 20 the main reinforcement 18 in the middle between the two thighs 40 a coplanar aligned U-bracket 16 (see also 12 ). The inside of the inner shell 4 located portions of the legs 40 are held comparatively long and extend here in the example over more than four grid meshes of the main reinforcement 18 So over more than 800 to 1,000 mm. The protruding outward sections have seen in the horizontal direction including the end arc 42 each a length of preferably about 400 mm. The subsequent assembly and connection in the area of the vertical joint between two wall elements 2 will be described below.

Finally, the reinforcement of the inner shell points 4 Right angled (eg curved or cast in this form) U-shaped bracket 44 or loops of steel, whose leg end 46 each in the space between the main reinforcement 18 and the surface reinforcement 34 lies. The comparatively short leg sections of the leg end extending over less than or at most one grid mesh 46 lie parallel to the horizontal reinforcing bars 20 the main reinforcement 18 , The bow end 48 this U-hanger 44 is perpendicular to the front 14 opposite back 50 and protrudes at least 200 mm into the later core filling 8th into it. It engages / engages behind the respective U-bracket 44 at the bend or bend or bending point 52 one of the vertical reinforcing bars 22 the main reinforcement 18 and touch it there. This is good in 3 and 4 to recognize the a corresponding longitudinal section through the later wall element 2 represent. In this way, at least some stitches, preferably most stitches, preferably each stitch of the main reinforcement 18 such a U-bracket 44 assigned. Is in 5 to recognize the complete structure of the reinforcement of the inner shell 4 just before concreting shows. In 6 the condition is shown after concreting.

After the inner shell 4 according to 6 and a correspondingly constructed outer shell 6 These are produced with the help of the in the subsequent core filling 8th protruding U-bracket 44 to a wall element 2 connected with each other. These are the two shells 4 . 6 brought into the desired relative position to each other, so that in each case the bow end 48 a U-bracket 44 the inner shell 4 and a U-bracket 44 the outer shell 6 lie directly next to each other and the straight leg sections overlap there and touch. The bows of the two U-bolts enclose 44 a substantially O-shaped opening 54 , This is good in 7 or 8th to see, in 8th For a better view the concrete filling of the outer shell 6 was hidden graphically. It also recognizes that the U-bolts 44 are arranged in rows, wherein the O-shaped openings 54 or loops of a row lying horizontally in a flight. Seen in the vertical direction, several of these rows are superimposed over the entire height of the wall element 2 evenly distributed (here, for simplicity, only two rows are shown). In each of these rows are two rebars 56 pushed in, extending over the entire width of the wall element 2 extend and are aligned horizontally according to the bracket assembly. The one rebar 56 is corresponding to that through the O-shaped openings 54 the bracket assembly granted free space to the inner shell 4 oriented, the other to the outer shell 6 out. The reinforcing bars 56 touch the corresponding bows of the U-bolts 44 from the inside in their vertices.

After inserting all reinforcing bars 56 in the space between inner shell 4 and outer shell 6 becomes the core filling 8th cast. The core filling 8th can be made of heavy concrete, taking into account any given requirements for the shielding effect against radioactive radiation. The heavy concrete core filling is also used for load transfer of the loads (namely, pressure loads in the element composite). To produce a high-quality composite, the concrete surfaces, which are connected via the potting compound, should have a grain skeleton-released surface. Concrete is a mineral building material and can be considered as artificial rock. It consists of a mixture of cement, aggregate and water. As a supplement mainly sand, gravel and grit are used. It is introduced into the forming formwork shortly before installation. Natural aggregates such as gravel from deposits or crushed rock (gravel, grit) are mainly used as aggregates for normal concrete. The addition significantly determines the processability and strength of the concrete. By a suitable grading of different aggregate sizes a dense packing of grains with few cavities in which the cement paste is sought. The dense packing allows the load transfer in the concrete through the grain stand.

After curing the core filling 8th does the in 1 illustrated composite of outer shell 6 , Core filling 8th and inner shell 4 like a monolithic object. The inner shells 4 and the outer shells 6 have a wall thickness S of each preferably at least 240 mm. The thickness T of the core filling is variable. For example, it can vary between 200 and around 550 mm. Accordingly, the wall element 2 Total thickness D in the range of about 700 mm up to 1,000 mm or slightly more. See also the supervision on the wall element 2 according to 9 in which the core filling 8th not yet available.

In 10 are from top to bottom the different steps in joining and connecting two adjacent wall elements 2 shown on the construction site. First, the two wall elements 2 brought into the desired position relative to each other, in which the peripheral U-bracket 16 the inner shell 4 on the one hand and the outer shell on the other 6 on the other hand overlap and touch in pairs. The bow of the respective bow 16 touches the shell edge of the adjacent wall element 2 , In other words enforce the protruding from the concrete mass strap sections the vertically extending butt joint 58 between the two wall elements 2 completely across its width.

Subsequently, lockable brackets 60 or steel rails over the paired U-bars 16 pushed. The brackets 60 form in the final assembly state each a closed rectangular frame whose longitudinal struts 64 horizontal and perpendicular to the lattice plane of the main reinforcement 18 (and thus also perpendicular to the U-hangers 16 ) are aligned, and its transverse struts 66 are vertically aligned. The rectangular frame encloses / spans the two associated with him, lying at the same level pairs of brackets of the inner shells 4 and the outer shells 6 of two juxtaposed wall elements 2 and touches them from the outside. Here, each pair of brackets are several, here four, in preferably the same distance next to each other, parallel aligned brackets 60 assigned (see also 13 ).

In the plan view of the vertical butt joint 58 This is through the U-bolts 16 and the brackets 60 divided into smaller rectangular spaces, which lie in the direction of the vertical extent of the wall element in alignment. Thus, in a sense, mutually delimited vertical sub-channels within the joint reinforcement are formed, in which in a further step vertically aligned reinforcing bars 62 , here three pieces, are inserted.

Finally, the thus reinforced, advantageously not significantly more than 400 mm wide vertical butt joint 58 poured with concrete, preferably with fine-grained concrete of comparable quality as the concrete of the inner shells 4 and outer shells 6 the wall elements 2 (Concrete quality C 50/60 or better). An intermediate stage during the casting process is schematically in 11 represents.

The transmission of traction in the horizontal joint between two stacked wall elements 2 takes place as already described by screwing the vertical main reinforcement 18 ,

The horizontal joint 68 (Storage joint) between two wall elements 2 - by flat spacers 70 spaced apart - are placed one above the other, is about 50 mm high and is poured after setting up the walls with a high-quality grout. The openings for the screw connection of the connecting elements 10 are also shed for the final state.

All wall elements 2 are immovably interconnected in the manner described and form as a whole a shear-resistant construction, which has the advantageous properties of a monolithic plate-disc element. The power transmission between the individual components is ensured by specifically designed connections and connections (tensile and shear-resistant connections).

It is understood that numerous variations of the wall elements are possible, for example, to allow ceiling connections, T-joints between outer and inner walls, corner joints, etc.

In addition to use of the described wall elements and connection techniques in nuclear power plant building construction, of course, an application in other buildings with similar high demands (eg military buildings, industrial plant buildings, etc.) is possible.

LIST OF REFERENCE NUMBERS

2

wall element

4

inner shell

6

outer shell

8th

core filling

10

connecting element

12

Front side (the respective shell)

14

engagement opening

16

Reinforcement loop / U-bracket (side connection)

18

main reinforcement

20

horizontal reinforcing bar (main reinforcement)

22

vertical reinforcing bar (main reinforcement)

24

joint

26

connecting bolt

28

Retaining plate

30

mother

32

box

34

surface reinforcement

36

horizontal reinforcing bar (surface reinforcement)

38

vertical reinforcing bar (surface reinforcement)

40

leg

42

bow

44

U-bracket (for shell connection)

46

leg end

48

arch end

50

back

52

Angling / kink

54

O-shaped opening

56

horizontal reinforcing bar (core reinforcement)

58

vertical butt joint

60

clip

62

vertical reinforcing bar (joint reinforcement)

64

longitudinal strut

66

crossmember

68

horizontal joint (bearing joint)

70

spacer

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2012/123067 A1 [0007, 0033]

Claims (10)

Wall element designed as precast concrete component ( 2 ) for the construction of a building with a substantially rectangular base area and four edges having wall body, the manner of a sandwich construction, an inner shell ( 4 ), an outer shell ( 6 ) and an intermediate core filling ( 8th ), wherein • the inner shell ( 4 ) is manufactured in reinforced concrete construction and a main reinforcement ( 18 ) consisting of a total of grid-shaped, each parallel to the edges extending horizontal reinforcing bars ( 20 ) and vertical reinforcing bars ( 22 ), which the inner shell ( 4 ) penetrate essentially from edge to edge, • the vertical reinforcing rods ( 22 ) at their ends with connecting elements ( 10 ) are provided for producing a screw or clamping connection with complementary connecting elements ( 10 ) of an above or below wall element ( 2 ) are formed, • a plurality of each angled at right angles, one leg end ( 46 ) and an arc end ( 48 ) having U-brackets ( 44 ), which with its leg end ( 46 ) in the inner shell ( 4 ), wherein the respective U-bracket ( 44 ) in the area of the bend ( 52 ) one of the vertical reinforcing bars ( 22 ) and with its curved end ( 48 ) into the core filling ( 8th ), and • the outer shell ( 6 ) analogous to inner shell ( 4 ) is constructed. Wall element according to claim 1, wherein substantially each of the lattice loops of the main reinforcement ( 18 ) into the core filling ( 8th ) projecting U-bracket ( 44 ) assigned. Wall element ( 2 ) according to claim 1 or 2, wherein the U-bolts ( 44 ) of the inner shell ( 4 ) and the U-bolts ( 44 ) of the outer shell ( 6 ) at their bow ends ( 48 ) overlap in pairs and each have an O-shaped opening ( 54 ) by at least one horizontal reinforcing bar ( 56 ) is passed as part of the core reinforcement. Wall element ( 2 ) according to one of claims 1 to 3, wherein one parallel to the main reinforcement ( 18 ) extending surface reinforcement ( 34 ) is available. Wall element ( 2 ) according to claim 4, wherein the leg ends ( 46 ) of the U-bolts ( 44 ) between the main reinforcement ( 18 ) and the surface reinforcement ( 34 ) lie. Wall element ( 2 ) according to one of claims 1 to 5, wherein for the production of a connection to laterally adjacent wall elements ( 2 ) laterally from the wall body outstanding U-shaped reinforcement loops ( 16 ) in the inner shell ( 4 ) and in the outer shell ( 6 ) are poured. Composite of several juxtaposed wall elements ( 2 ), each formed according to claim 6, wherein the reinforcement loops ( 16 ) of immediately adjacent wall elements ( 2 ) in the vertical butt joint ( 58 ) overlap in pairs, and wherein each pair of loops of the inner shell ( 4 ) with a pair of loops of the outer shell ( 6 ) by a bracket ( 60 ) is spanned. Composite according to claim 7, wherein in the vertical butt joint ( 58 ) at least one vertical reinforcing bar ( 62 ) is arranged. Composite of wall elements ( 2 ), each formed according to one of claims 1 to 6, wherein superimposed wall elements ( 2 ) via the connecting elements ( 10 ) are bolted together or braced. Composite of wall elements ( 2 ) according to claim 9, wherein horizontal bearing joints ( 68 ) and vertical butt joints ( 58 ) between the wall elements ( 2 ) are poured with concrete and / or mortar.

Images