Advantages of prefabrication of parts of buildings are widely recognized in case of substantial number of similar units. Techniques of construction implying precast elements at various stages and extents are widely available.

Precast columns and beams for the structure, wall panels, slabs, concrete joists and boards for floor systems, as such, separately or in various combinations, are also well known.

For construction on site, materials and taken to the construction site in their elemental state, and are used for building: cement, aggregates, water, bricks, blocks, etc.

For precast systems, all or part of elements such as columns, beams, slabs, walls, are precast in factory and transported on construction site for assembly.

Complete precast units also exist.

There is a choice to be made in regard of the level of aggregation of the construction materials, from raw materials to be used on site, to the ready built buildings.

DISCLOSURE OF THE INVENTION The concrete building shoppable in small parts according to the present invention, is to be understood as a concrete building made of such small elements that one can find them in a warehouse, shop, transport and go to assembly without calling on highly specialized equipment, or on highly specialized skills. The building is broken out and cast in small elements for this purpose. The foundation and the roofing are kept out of the present disclosure.

This objective is achieved better if the three main components involved are independent. The structure needs to work as a true backbone on which walls and slabs are simply attached, thus bearing all the loads and resisting to all the moments. It remains for walls only to bear their own weight and to separate areas of the building. Similarly, it remains for the slabs only to bear their own weight and the loads due to their occupancy. This means that walls and slabs don't play any structural role anymore.

This complete specialization makes it possible to go further and allows breaking out of the said components in smaller and smaller elements until we reach the desired level of aggregation.

If we take an example of making a wall of the following dimensions: Length of 2 m, height of 2 m and thickness of 0.2 m, with cement blocks. Technically, it is possible to make 1 cement block of the size of the wall, 4m ² , and just pose it and fix it properly to the structure. It is also possible to make 4 cement blocks of 1 m ² each, and assembly them on construction site using cement mortar. It is also possible to use 40 cement blocks of 0.1 m ² each, and assembly them on construction site using more cement mortar. Each of the above options has its advantages and disadvantages.

Similarly, at the top of aggregation of construction materials, we have ready built buildings, while at the bottom of aggregation we have buildings completely made on construction site.

For the shoppable concrete building object of the present invention, the level of aggregation of the precast elements as well as the method for designing them has been chosen to fit with a basic method for handling, transport, mounting and assembling them with usual accessories such as screws, bolts and nuts, rivets, rods, etc. with eventually a few welding or cast to be done in situ. The said accessories play the key role of the mortar when there is no significant aggregation of construction materials. Additionally, the possibility of making wedges, lugs and the like plays also a role in determination of the level of aggregation. It results in a different practice for construction of building.

It is to be noted that the ways and modes of realization of the invention hereinafter are given as examples; similar ways and modes can be undertaken.

Firstly, there is a need of a self-sufficient structure designed to bear all the loads and to resist to all the moments without any other contribution whichever from walls or floors. Indeed, it is worth to make efforts in realizing a self-sufficient structure of the building, because it results in a lot of advantages for walls and floors design.

The structure disclosed in the patent document WO 2016/189476 A1 is convenient for this purpose. It is a precast concrete structure highly triangulated vertically and horizontally. It may be subsequently demountable in columns, beams and braces as well, in case of need. Although other types of structure may fit, this structure is adopted by the present invention with a few modifications, mainly for dividing elements in pieces easily shoppable if needed, depending on the size of the elements, and for making holes for handling purpose.

With such a structure, the requirements for walls and floors become easy to fulfil. There is no more need of loadbearing or shear walls. The eventual contribution of walls in the role of the structure is marginal and will be considered as a bonus. A simplified type of wall, fitting with the concept of shoppable concrete building at the level of aggregation chosen for the present invention, is described below.

A current typical partition wall is the stud wall. Its framework is constructed of wood or metal studs, which are attached between them by one or two horizontal bridges.

Panel sheets such as drywalls are then attached to both side of the frame. Other materials such as fibre cement boards are also more and more being used for that purpose.

The following patent documents can be considered as close to walls according to the present invention:

US 3,888,059 relating to a removable partition wall;

US 5,784,850 relating to a stud wall system;

US 8,356,453 B2 relating to bracket and bridging member for a metal stud wall; US 2004/0231274 A1 relating to collapsible stud wall, metal, load bearing and non- bearing;

US 2007/001 1971 A1 relating to a wall framing assembly and method of securing a stud to a header or footer.

US 8,387,321 relating to drywall trims.

Let's take into consideration a 3000 meters high stud wall, with wood studs spaced 400mm and one horizontal bridge made of timber of 150x50mm.

We can increase more and more the number of vertical studs and horizontal bridges. It will result in a wall with several advantages which make it more shoppable: lightweight, easy to mount in the structure, less sensitive to shock, soundproof, easy to reinforce mechanically, etc.

In addition, with the reduction of the free area between members of the framework, we can reduce the size of the said members as well.

At a certain thickness of the framework elements of the stud wall, it become interesting to shift to another type of material: panels. Using thin walls structure elements such as panels fits with short distances between them. It practically results in an alveolar wall. Such a wall can be compared to a large cupboard with sides and shelves with more or less thickness, with more or less large openings. These openings can be designed not only for supporting the wall panels, but also to be used for storage. Therefore, the deepness of a wall or of part of it, can be increased for that purpose, and designed beyond the needs of implementation of a partition wall. To reduce the risk of fire, not flammable materials such as fibre cement boards are preferably used, totally or partially.

Alveolar or cupboard walls lead to a lot of advantages. One can mention in particular: it is lightweight, cost effective, reduction of risk of fire, no risk of termites and rot fungi, large storage space within walls, possibility of reinforcement with metal grid, possibility of preparation of insulation blanket in standard units, etc.

Alveolar wall is stronger than a stud wall and can provide to the building a lateral resistance at a certain extent.

If we keep comparing the wall with a cupboard, panels constituting shelves or horizontal members have to be nailed, stapled, hooked or fixed by other means to panels constituting sides or vertical members.

In case thin panels are used, metal fixtures for fixing thin panels may result in elevated risk of splitting. To prevent it, edges of area in which metal pins such as nails, screws, staplers' pins, will penetrate are provided with flanges to enlarge their surface at the area of contact. It results in an I-beam like panel and results in a strong link between elements of the alveoli.

The said flanges can be in one piece with the web of the I panel, or be made of different pieces, even of varied materials. This arrangement makes it easier to implement various angles between cupboard shelves and the sides.

Another solution to avoid splitting of thin panel is fixing it into a grove made in the perpendicular panel. Any contribution to lateral resistance of a building is always welcome. Alveolar wall can provide a substantive contribution in this scope if elements of alveoli or a part of them are designed slantwise instead of being just vertical and horizontal. Such a wall can be shopped as a whole at the same time as the structural elements, or easily assembled on site.

Another advantage of alveolar partition wall is the possibility offered to add a mechanical reinforcement against abuse, particularly for external walls. Such mechanical reinforcement can be made of metal or reinforced concrete grid. This constitutes an important aspect of the present invention, because otherwise one could be feared to use the technique only for security reasons.

In addition to the choices made regarding the level of aggregation of the structure and of walls, a choice of aggregation for the floor has been made according to the present invention. It has been broken out into small elements. Details of an example of such a floor are given below. Its contribution in the role of the structure is marginal and should be considered as a bonus. Analogically to partition walls, this type of floor could also be called partition floor to gives a good image of the principles which are behind its design. According to the present invention preliminary holes are performed in the structure elements for subsequent and efficient assembly of floor elements. These elements play a key role in determining the desirable level of its aggregation.

The floor is basically a one-way simply supported slab, not continuous over a span. It derivates from slab supported by double T beams, which is itself an advanced improvement from the classic solid slab for efficient use of material.

For the purpose of the present invention, we break it up into small components: joists and upper plate, subdivided itself in several panels.

To the joists and upper plate, we add a low plate for increasing mechanical stability, fire protection and insulation. It also constitutes the ceiling for the immediately lower floor. These plates are made under the form of reinforced concrete boards or planks, cement boards or the like. The upper one is generally stronger than the low one.

Joists, upper and low plates are cast separately and will be assembled subsequently in factory or partially on construction site, to constitute the suspended slab. For this purpose, they will be provided with holes of appropriate diameter which coincide ones to the others, and which are placed at an appropriate distance, for example 10mm diameter holes placed at 100mm.

The section of screws and the spacing used are then comparable to the ones of the stirrups joining upper plate and joist in a usual concrete double T beam.

The upper and low plates are preferably cast in full length elements. They are laid perpendicularly to the concrete joists, at the upper face and the low face thereof. It will then result in a system comparable to joists floor system in wood construction.

Another common point with these two systems of floor is the use of hangers.

In the fabrication of the joists object of the present invention, some provisions are taken to ensure a safety level which cannot be reached with the wood joists floor.

Indeed, for example in a wood building, in case the highest floor would collapse for any reason, it would fall on the floor just below, which probably will collapse as well, and so on. However, the number of floors is generally reduced in wood construction. Hence, that risk is limited in the same measure. But in concrete buildings the risk is higher and cannot be neglected, mainly for two reasons: the number of floors involved is generally higher, and the slabs are heavier than wood floors. The suspended slab must then meet not only the bending moment and deflection criteria, but the safety one as well.

To eliminate the risk of successive collapse of floors, the reinforcements of the joists are tied to the metal hanger preferably by welding. In turn, the hanger is securely fixed to the beam. This can be achieved by using long and strong screws, bolts, rods, rivets, or the like, placed behind at least one of the main reinforcements of the beam. The low end of those assembly accessories arrives under the level of the said reinforcement. It may also have an oblique orientation heading under the said reinforcement, to make a hook like pattern with the hanger, which holds the said main reinforcement in its bend. Thus, in case of extreme conditions which would result in the suspended slab to fall, it would be retained by the hangers strongly tied to the beam and the assembly accessories holding beams reinforcements in their hooks.

For the same safety reasons, the length of assembly accessories between concrete joists and plates goes beyond the assembly requirements, to meet safety needs as well.

Thereby, the joists are advantageously provided with two top and two bottom bars, so that the assembly accessory with the joist will pass between them.

Making joists separately from the upper and low plates allows their achievement in small thicknesses. The low limits of thickness are given by their workability, their mechanical stability and their protection against fire. Therefore, so thin precast concrete joists and plates require taking some provisions for handling and reinforcement.

They may be made with two types of reinforcement at the same time: the usual rebars on the one hand, and perforated sheet, expanded metal or similar material on the other hand. Such a double reinforcement results in higher strength and stiffness. They also allow to deal efficiently with punching shear particularly for the upper plate.

According to the invention, attention must be payed to the handling of freshly cast elements, particularly for the thin ones such as panels and joists.

For this purpose, we take advantage of the preliminary holes made for assembly purpose, for they are distributed all along the precast element, and we use them for handling purpose as well. The holes length is then extended beyond the assembling requirements, to meet the handling needs, too. We may also perform special holes only for handling purpose. Handling devices will then be applied to rods or the like inserted in the said holes.

Freshly cast elements can also be handled using thin plates or other devices inserted under the element and distributed all along its length.

To make the building truly shoppable, the precast elements thereof must be easy to handle, transport and mount without calling highly specialized equipment such as tower cranes. For the purpose of the present invention, a basic handling-lifting equipment is sufficient. It must be possible to carry it or lift it up to the following floor to be built, so as it will operate from there for lifting in its turn columns, beams, walls, etc. for the respective floor and assembly them.

Being in that position, it will also lift and pose the slab's components for the floor immediately above, and assembly them. For the range of the weights to be handled, and given that the operations to be done are not extensive, basic handling-lifting devices are sufficient: lifting mast, gantry, etc. The simplest is the lifting mast, with electric hoist and manual rotation. It will have to operate in reduced spaces and in the height. The load lifted and suspended at an end of the boom must be balanced by a counterweight leading to an equivalent moment, located symmetrically with respect to the mast.

For many reasons, it is not preferred the counterweight be suspended in the height at the other end of the boom. A better place is at the same level as the mast support. It is often part of the latter. It is the same thing with tower cranes where the counterweight, or a major part of it is placed at its base.

When the mast rotates, it must find a sufficient counterweight in its successive positions. Otherwise it will be unbalanced and could even collapse. A solution according to the invention is to rotate in the same measure the chassis on which both the mast and the counterweight are fixed. For this purpose, it is advantageous that wheels of the chassis on which the mast is mounted, rotate freely or is all wheels steering, preferably with an angle greater than 90°, at least when the boom is rotating. The mast can then achieve a 360° rotation at the same time with the chassis in case of need.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 represents a view of the cupboard wall frame.

We distinguish an alveolus (1 ), one of the shelves (2), a side of an alveolus (3), the bottom board (4), the top board (5) and a side board (6).

Fig. 2 represents partial view of two panels simply assembled.

Fig. 3 represents a partial view of a joint with groove. An edge of one of two perpendicular panels is inserted into a grove realized in the other panel.

Fig. 4 represents a partial view of an I panel with independent flanges.

We distinguish the independent flanges (7).

Fig. 5 represents a section view of two panels separated by a simple panel.

We distinguish the spacer panel (8).

Fig. 6 represents a section view of the same panels separated by a panel whose edges are inserted into grooves.

We distinguish the spacer panel (9) inserted into a groove.

Fig. 7 represents a section view of the same panels separated by an I panel whose web and flanges are made in one piece.

We distinguish an I panel (10) whose web and flanges are made in one piece. Fig. 8 represents a section view of the same panels separated by an I panel whose flanges and web are separate pieces.

We distinguish an I panel (1 1 ) whose web and flanges are made in separate pieces.

Fig. 9 represents a section view of the same panels separated by special I panels able to form any angle with the adjacent panels.

We distinguish special I panels (12) whose flanges allow different angles with the adjacent panels.

Fig. 10 represents a section view of a frame with alveoli arranged slantwise.

We distinguish bottom board (4), top board (5), a side board (6), double panel door header (13) and double panel door frame (14).

Fig. 1 1 represents a section view of a joist and upper and low plates. We have the joist (15), the upper plate (16), the low plate (17), assembly accessory (18), and coincide holes (19).

Fig. 12 represents a section view of a beam, a joist, and a hanger. We have the joist (1 5), a joist frame part of the joist and of the hanger as well (20), the beam (21 ), the longitudinal reinforcement of the beam (22), a hanger on the other side of the beam (23), and a screw for assembling on site (24).

Fig. 13 represents a detailed section view of a joist. We see a joist frame part of the hanger (20), a longitudinal reinforcement (25), and an expanded metal reinforcement (26).

Fig. 14 represents a section view of a panel. We see an expanded metal reinforcement (27), a cross hole (28), and a longitudinal reinforcement (29).

Fig. 15 represents a section view of a beam with vertical accessory, in a straight way. Fig. 16 represents a section view of the same beam with vertical assembly accessories into place following a skew nailing pattern. The following screw is fixed in slant position but with a different angle.

Fig. 17 represents a section view of a beam with horizontal accessory in a straight way.

Fig. 18 represents a section view of the same beam with horizontal assembly accessory in place following a skew nailing pattern. The following screw is fixed in slant position but with a different angle.

BEST MODE FOR CARRYING OUT THE INVENTION

First of all, there is factory prefabrication for the above-mentioned elements of the building: structure, floors and walls. After proper curing of the precast elements, they are stored in a warehouse for sell. Design of the said elements is made in accordance with the local construction codes. Some choices are made to have for example columns and beams of commonly used sections and lengths.

Due to the possibility of customization of the fabrication, joists and upper plates of higher strength are also available for supporting partition walls which are not directly supported by structural beams. Are also available accessories, and handling-lifting devices to hire and/or to sell with buyback options.

Support organization: Commercial and technical support: templates plans for houses, demonstration videos, comparative tests, various support.

Once on the construction site, for mounting building elements of the ground floor, the handling-lifting device is operating from the ground, from outside or inside the building. The slab of the first floor, which is at the same time the ceiling of the ground floor, is also posed, because the lifting device will stand on it during the following step. Low plates are also fixed to ensure mechanical stability of the slab.

The second step consists of moving the lifting device onto the first floor, preferably after it has been demounted into small parts, so that it can be carried easily through stairs or hoisted through joists or along external walls, and do the same operations for the first floor, as previously done for the ground floor, and so on with subsequent floors.

To ease operations during the construction, structure and slabs can be built first, and walls mounted subsequently, preferably starting from the walls of the highest floors. For any reason, one can choose to use another type of structure, of walls or floors than those described herein.

INDUSTRIAL APPLICABILITY

Currently a concrete building is mostly considered as a big black box whose secrets are reserved to engineers and architects. The primary purpose of the invention is to bring the construction of concrete buildings at the reach of owners without highly specialized equipment and skills. Construction of some houses and buildings, preferably those with small pieces such as individual houses, residential apartments, hotels, schools, etc. can be made more easily, more quickly, and with more satisfaction of the owner, than in the classic construction system. This may notably be due to his active participation all along the process, and the better understanding of how it works. Comparable situation is met in wood construction. Quality is increased for every element of the building involved: structure, floors and walls. By shopping a finished product, one will not fear disappointments at the end of the process due to more or less failures all along activities conducted on site. It is well known that factory conditions are much better than site conditions.

The method is ecofriendly, particularly due to the possibility offered for:

- customization of the strength of a limited area at the stage of designing, for example joists our plates supporting a partition wall;

- easy repair of limited area in case of disasters at the stage of exploitation;

- disassembling for disposal or recycling at the end of its lifespan or for any other reason.