HRP990305A2 - Composite roof and floor structure with flat soffit for the construction of halls - Google Patents

Description

The field of technology

The subject of the invention is a composite roof-ceiling structure with a flat underlayment for the construction of halls.

According to the International Classification of Patents, the field of technology from which the invention originated is designated by group E04C-003 / 294 / IC under the name: "Construction load-bearing parts of an elongated shape. Beams; Girders, ties or similar construction parts, e.g. prefabricated, composed of concrete together with a lattice structure projecting laterally outside the parts "

Technical problem

The composite roof-ceiling structure with a flat underlay for the construction of halls is intended for the construction of hall roofs with a span of over 10 m.

The invention solves several technical problems:

Plate supports with large floor plan dimensions cover a large part of the building's floor plan surface at once.

The final flat ceiling is obtained, which does not need to be processed afterwards. Halls with this type of ceiling have a higher-quality flat view than the usual ones, where the roof supports are not visible from the hall, and the roof slopes are eliminated, which reduces the volume of the heated space.

Thermal insulation is placed on the upper surface of the slab, it is simply installed and a shallow attic space is formed above the concrete slab, which enables efficient ventilation.

The construction enables safe work at height during the assembly of the cover and the laying of insulation, where all work is performed on the flat, upper surface of the panels.

State of the art

In typical production programs, the roof and ceiling structures are mostly handled separately.

Composite concrete-steel constructions with steel in the upper pressure zone are mainly used as temporary, until pouring with concrete, such as the "Omnia" system, or as temporary support with secondary fillings on small spans, such as the "Fert" system.

It is unusual to use concrete as a material extremely sensitive to the train for the sole purpose of taking over the train and conversely, steel prone to buckling and suitable for taking over the train as a pressure belt.

Concrete in the lower zone of combined steel-concrete elements is often used to coat the steel for the purpose of corrosion protection. Even more often, composite plate girders reinforced with steel gratings from below are encountered as coupled girders.

The use of steel as a compression element in a steel-concrete composite beam is usually uneconomical due to the high self-weight of the concrete. In the subject invention, the bottom plate is also the finished ceiling, so it is profitable to use steel as a pressure element of the structure.

The essence of invention

The essence of the invention consists in the original application of a thin and wide concrete slab (reinforced concrete or prestressed) as the lower tensile belt of the spatial-linear structure, reinforced with a steel lattice structure above, and its use of the concrete slab as a final processed flat ceiling that enables; simple process of thermal insulation, reducing the useless volume of the hall, i.e. it ensures savings in space heating, forms a ventilated space above the thermal insulation and enables safe work at height.

The construction as a whole represents an unusual way of using concrete as a material that cannot withstand a train, and steel, which is usually used in composite elements made of concrete and steel to pick up a train.

The fact that the ceiling slab, needed to cover a large area of the floor plan as a tensile element of concrete with a large cross-sectional area, was used, so the tensile stresses in its concrete reach a low level that is below the limit of the formation of cracks, which gives the structure the necessary elasticity and great ductility.

Description of images

Figure 1 shows a cross-section of a composite roof-ceiling structure for the construction of halls with a flat bottom view

Figure 2 shows an axonometric view of composite roof-ceiling constructions with a flat bottom view for the construction of halls

2a) with flat filling

2b) with space filling

Figure 3 shows a detail of the connection between the reinforced concrete slab and the steel grid.

3.a in cross section

3.b in longitudinal section

Figure 4 shows the possible variants of steel constructions above the slab in terms of types and static system

4.a as a support with vertical filling rods

4.b as a lattice support

4.c as a full-wall steel support

4.d as a full-wall steel support with a perforated rib

Figure 5 shows possible versions of the steel structures above the slab in terms of the longitudinal contour

5.a double-roofed longitudinal drop

5.b single-roofed longitudinal drop

5.c parallel belts

Figure 6 6.a shows a detail of the welding of the filler rods to the upper belt

6.b shows the effect of lifting the structure due to welding

Description of the performance and application of the invention

The composite roof-ceiling structure for the construction of halls with a flat bottom view shown in pictures 1,2,3,4 and 5 represents a roof-ceiling, prefabricated, composite, linear-spatial element intended for prefabricated construction of halls, which consists of a wide and thin ceiling panel (1), steel grids above the slab (2), possible different fillings (3), tied with a special detail (pictures 3a and 3b) to the ceiling slab, insulated from above with a layer of thermal insulation (4) which is subsequently laid on the slab. The upper belt of the steel structure (2) serves to carry the secondary supports (10) and the cover (11).

The ceiling slab is applied in specific proportions that characterize a very thin and wide concrete slab (height/width = 1/60 to 1/30, width/span = 1/4 to 1/7. The concrete slab can be made in variants such as reinforced concrete or prestressed.

The steel grid of the structure can be of different forms of filling and static systems (figure 4a, 4b, 4c and 4d), planar or spatial along the main longitudinal axis of the support, i.e. with rods in one or more planes (figure 2a and 2b).

Insulation (4) made of mineral wool is laid on the flat ceiling panel (1) during the construction of the roof, so the purpose of using a light steel grid with rods is to achieve as small a cross-sectional area as possible of its rods (3) in order to reduce the transfer of heat from the uninsulated attic space (9). into the concrete slab (1) and unhindered laying of the insulation (4).

The structure in its entirety, in a static sense, represents a freely supported, linear-space grid with an upper steel (2) and a lower concrete belt-plate (1), which represents an inversion in relation to the usual way of using concrete as a material used for pressure elements and steel which is applied to pick up the train.

The invention is at the same time a roof and ceiling construction with a finished ceiling, because the concrete slab (1) is used in addition to its load-bearing function and as a final ceiling that does not need to be processed after installation. The fact that the ceiling slab, needed to cover a large area of the floor plan as a tensile element of concrete with a large cross-section, was used, so the strain in its concrete reaches a very low level, which is below the limit of the formation of cracks.

The concrete ceiling slab (1) is connected to the steel part of the structure with the detail shown in Figures 3a and 3b.

The steel structure (2) and (3) is made by welding or screwing the component steel parts.

The reduction of large deflections is achieved by the welding sequence, i.e. by a kind of thermal prestressing. which

The detail of the connection of the steel part of the structure with the concrete slab (1) is performed at the end of the filler rod (3) with drilled holes (5) of the required diameter, through two walls, through which the longitudinal reinforcement bars (6) or prestressing ropes are passed. The reinforcement of the concrete slab consists of an upper grid (7) which carries the slab with longitudinal rods as a double-sided cantilever around the central longitudinal axis of the structure and a lower grid (8) which carries together with rods or ropes (6) in the longitudinal direction.

By pulling longitudinal bars or ropes for prestressing (6) through the two walls of the infill rod of the steel structure (3), the rotation of the infill rod (3) is prevented regardless of the deformation of the concrete slab, i.e. the separation of the rigid rod (3) from the shallow connection with the concrete slab is prevented ( 1) which forces them to do joint deformation work, i.e. transfer bending moments, so the global bending moment is broken and transferred to the concrete slab (1) and it is additionally employed as a load-bearing element. The lower mesh for reinforcing plates (8) is placed in the plate mold under the longitudinal reinforcement bars or prestressing ropes (6) and then the longitudinal bars or prestressing ropes (6) are passed through, while the upper mesh (7) is placed over the bars or ropes ( 6) as an elevated longitudinal support, which ensures a double cantilever reinforcement of the cross section.

The construction is very sensitive to deflections, which cannot be eliminated by the available, centric prestressing of the plate with a very small eccentricity, so a special prestressing is applied (Figure 6a and 6b), which is performed by welding the filler rods, in order from the ends to the middle, (3) on the upper construction belt (2) after hardening of the concrete slab (1), whereby the upper lattice belt (2) tends to deform upwards, which is opposed by the concrete slab's own weight, which causes the effect of prestressing and reduction of deflection. The magnitude of the prestressing effect is achieved by the arrangement, lengths and thicknesses of the welds. The welds (12) essential for achieving the lifting effect of the steel structure are perpendicular to the cross-section of the upper belt (Figure 6a), which is deformed from the initial longitudinal shape (13) to the final shape (14).

Claims (4)

1. Composite roof-ceiling construction with a flat underlay for the construction of halls characterized by the fact that it consists of a distinct reinforced concrete or prestressed concrete slab (1) with a steel part of the structure (2) that serves to carry secondary supports (10) and cover (11) and it is located above the concrete slab (1), with a statically arbitrary planar or three-dimensional rod filling (3), with a single-roofed, double-roofed or parallel lower slab upper belt (2), with thermal insulation (4) which is laid on the upper surface of the slab (1 ), with a ventilated blind ceiling (9) 2. Composite roof-ceiling construction with a flat underlay for the construction of halls according to patent claim 1, indicated by the fact that the rods are filled (3) through which the longitudinal bars of the reinforcement (6) are passed through the drilled holes (5) through both walls. 3. Composite roof-ceiling construction with a flat underlay for the construction of halls according to patent claim 1, characterized by the fact that the deflection of the concrete slab (1) is eliminated by prestressing, which is achieved by welding the infill rods (3) to the upper belt of the steel structure (2) after hardening of the concrete slab. 4. Composite roof-ceiling construction with a flat underlay for the construction of halls according to patent claim 1 characterized by the fact that it is applied in specific proportions that characterize a distinct thin and wide concrete slab with proportions; height/width = 1/60 to 1/30, width/span = 1/4 to 1/7.