Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
REINFORCEMENT SYSTEM FOR STEEL-CONCRETE COMPOSITE SLABS WITH PROFILED SHEET
Document Type and Number:
WIPO Patent Application WO/2019/186401
Kind Code:
A1
Abstract:
Reinforcement system for steel-concrete composite slabs with profiled sheet, comprising a longitudinally profiled sheet with an upper longitudinal flange and a lower longitudinal flange, wherein the upper longitudinal flange has a longitudinal stiffener in the form of an upward fold with mutually spaced cuts, wherein each cut is vertical to receive a bar transverse to the profiled sheet. In an embodiment, said cuts terminate in a bore-shaped cutout at the base of said cuts for fitting said transversal bars. In an embodiment, said cuts have a width less than the diameter of said transversal bars and the bore-shaped cutout at the base of said cuts has a width equal to or greater than the diameter of said transversal bars, for fitting and retaining said transversal bars.

Inventors:
DUARTE SIMÕES RUI ANTÓNIO (PT)
FELIZ PINTO LOPES DA CRUZ ANTÓNIO (PT)
Application Number:
PCT/IB2019/052458
Publication Date:
October 03, 2019
Filing Date:
March 26, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
O FELIZ METALOMECANICA S A (PT)
UNIV DE COIMBRA (PT)
International Classes:
E04B5/40; E04C5/04; E04C5/06
Domestic Patent References:
WO1994010385A11994-05-11
Foreign References:
DE2600662A11977-07-21
DE2729445A11979-01-11
DE2413645A11975-09-25
EP0480592A11992-04-15
CA2632372A12009-11-27
Attorney, Agent or Firm:
SILVESTRE ALMEIDA FERREIRA, Luis Humberto (PT)
Download PDF:
Claims:
C L A I M S

1. Reinforcement system for steel-concrete composite slabs with profiled sheet, comprising a longitudinally profiled sheet with an upper longitudinal flange and a lower longitudinal flange, wherein the upper longitudinal flange has a longitudinal stiffener in the form of an upward fold with mutually spaced cuts, wherein each cut is vertical to receive a bar transverse to the profiled sheet.

2. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said cuts terminate in a bore-shaped cutout at the base of said cuts for fitting said transversal bars.

3. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said cuts have a width less than the diameter of said transversal bars and the bore-shaped cutout at the base of said cuts has a width equal to or greater than the diameter of said transversal bars, for fitting and retaining said transversal bars.

4. Reinforcement system for steel-concrete composite slabs with profiled sheet according to any one of the previous claims, comprising a set of transversal reinforcing steel bars which comprises one or more transversal bars for placing in said cuts.

5. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said set of transversal reinforcing steel bars further comprises a welded wire mesh, welded to said transversal bars, in particular welded by electro-welding.

6. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said welded wire mesh is formed by said transversal bars and by longitudinal bars.

7. Reinforcement system for steel-concrete composite slabs with profiled sheet according to any one of the previous claims, comprising a set of transversal reinforcing steel bars which comprises one or more transversal bars for placing in said cuts, wherein the transversal bars comprise downward folds in the lower longitudinal flange for supporting longitudinal bars.

8. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said set of transversal reinforcing steel bars comprises said longitudinal bars.

9. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said transversal bars and said longitudinal bars are welded together.

10. Reinforcement system for steel-concrete composite slabs with profiled sheet according to any one of the previous claims, comprising a set of transversal reinforcing steel bars which comprises one or more transversal bars for placing in said cuts, wherein the transversal bars comprise upward folds in the upper longitudinal flange for supporting a distribution welded wire mesh.

11. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said set of transversal reinforcing steel bars comprises said distribution welded wire mesh.

12. Reinforcement system for steel-concrete composite slabs with profiled sheet according to the previous claim, wherein said transversal bars and said distribution welded wire mesh are welded together.

13. Reinforcement system for steel-concrete composite slabs with profiled sheet according to any one of the previous claims, wherein the profiled sheet and the transversal bars are not welded together.

14. Reinforcement system for steel-concrete composite slabs with profiled sheet according to any one of the previous claims, wherein the longitudinally profiled sheet and the transversal bars are arranged perpendicularly to each other.

15. Reinforcement system for steel-concrete composite slabs with profiled sheet according to any one of the previous claims, wherein the profiled sheet has a trapezoidal profile.

Description:
D E S C R I P T I O N

REINFORCEMENT SYSTEM FOR STEEL-CONCRETE COMPOSITE SLABS

WITH PROFILED SHEET

Technical Domain

[0001] The present description relates to a reinforcement system for steel-concrete composite slabs with profiled sheet for particular application in the construction of building structures.

Background Art

[0002] CA2632372 discloses a steel-concrete composite slab with trapezoidal profiled sheet, with fastening elements connecting a metal beam to a profiled sheet and to the concrete through a substantially rectangular base and two flat and inclined side parts, which widen progressively from the base, preferably having a cutout for receiving a bar.

[0003] The prior art can benefit from a reinforcement system for steel-concrete composite slabs with profiled sheet which allows obtaining greater resistance and easier on-site assembling.

[0004] These facts are described in order to illustrate the technical problem solved by the embodiments of the present document.

General Description

[0005] It is an object of the present embodiments to provide a solution for the reinforcement of steel-concrete composite slabs with profiled sheet for particular application in the construction of building structures, pedestrian walkways, roofs, floors, among others. [0006] The present description relates to a reinforcement system for steel-concrete composite slabs with profiled sheet which allows obtaining greater resistance and easier on-site assembling.

[0007] The proposed solution comprises a set of transversal reinforcing steel bars, distributed along the span, placed in vertical cuts executed in longitudinal stiffeners, for example in inverted V-shape, located in the upper flanges of the profiled sheet. The function of the bars includes to avoid the relative displacement between the steel sheet and the concrete in the longitudinal direction, allowing the slab to develop its entire bending strength. When the system is requested, the shear strength of the bars and the bearing strength of the sheet are mobilized. The longitudinal locking due to the cut in the sheet is very effective, also allowing to place the bars easily. The bar itself also allows to obtain a very effective anchorage in the concrete. The transference of longitudinal shear forces is all the more effective the greater the thickness of the steel sheets. From the constructive point of view, the transversal bars can also be used to assist in the positioning of longitudinal bars, if present, or even of the distribution wire mesh.

[0008] To prevent the bars from loosening during concreting, these are fitted into a hole-shaped cutout located at the base of the vertical cut, whose diameter, approximately equal to the diameter of the bar, may be slightly larger than the width of the cut, thus obtaining a snap fit between the bar and the profiled sheet.

[0009] The reinforcement system may be designed as:

(i) simple system of transversal reinforcing steel bars uniformly distributed along the span (base system described above);

(ii) reinforcement system integrated in a welded wire mesh to simplify the application thereof; or

(iii) reinforcement system integrated in a welded wire mesh, where the transversal bars bend downwardly in the region of the sheet ribs to support possible longitudinal bars, possibly used to increase the steel-concrete composite slab bending and/or fire capacity (Figure 2c and 2d). [0010] As an alternative to system (iii), the transversal bars may also bend upwardly and serve as a support for the distribution wire mesh, which must be placed close to the upper surface of the slab.

[0011] In both situations the system will be able to prevent the use of spacers or other devices for the positioning of the longitudinal reinforcing bars and/or distribution wire mesh.

[0012] Alternatively, it is possible for the transversal bars to bend upwardly and downwardly, for example alternately, to support longitudinal bars on the ribs and to serve as a support for a distribution wire mesh.

[0013] The main advantages of the proposed system include:

Increased load bearing capacity of slabs due to increased longitudinal shear strength;

Possibility of combining with the most common longitudinal shear resistant system constituted by embossments along the sheet;

Longitudinal shear capacity is no longer dependent on other possible reinforcement systems, such as the end anchorage device of welded headed studs in the supporting beams through the steel sheeting, which requires well done in-situ welding techniques;

Increased ductility of the slabs because the most probable collapse modes (bending or even longitudinal shear) are ductile;

Increased transversal stiffness in the plane of the slab, which makes the diaphragm effect more effective, beneficial for resistance to horizontal actions, such as the action of the wind or the action of an earthquake;

Support for the placement of other wire meshes (longitudinal and/or distribution) required for other functions;

Ease of commissioning (cuts pre-designed in factory).

[0014] These facts are described in order to illustrate the technical problems addressed by the present description. [0015] A reinforcement system for steel-concrete composite slabs with profiled steel sheet is described, comprising a longitudinally profiled sheet with an upper longitudinal flange and a lower longitudinal flange, wherein the upper longitudinal flange has a longitudinal stiffener in the form of an upward fold with mutually spaced cuts, wherein each cut is vertical to receive a bar transverse to the profiled sheet.

[0016] In a preferred embodiment, said cuts terminate in a bore-shaped cutout at the base thereof for fitting said transversal bars.

[0017] In a preferred embodiment, said cuts have a width less than the diameter of said transversal bars and the bore-shaped cutout at the base of said cuts has a width approximately equal to or greater than the diameter of said transversal bars, for fitting and retaining said transversal bars.

[0018] A preferred embodiment comprises a set of transversal reinforcing steel bars comprising one or more transversal bars for placing in said cuts.

[0019] In a preferred embodiment, said set of transversal reinforcing steel bars further comprises a welded wire mesh, welded to said transversal bars.

[0020] In a preferred embodiment, said welded wire mesh is formed by said transversal bars and by longitudinal bars, possibly of smaller diameter.

[0021] A preferred embodiment comprises a set of transversal reinforcing steel bars comprising one or more transversal bars for placing in said cuts, wherein the transversal bars comprise downward folds in the lower longitudinal flange for supporting longitudinal bars in the ribs.

[0022] In a preferred embodiment, said set of transversal reinforcing steel bars comprises said longitudinal bars.

[0023] In a preferred embodiment, said transversal bars and said longitudinal bars are welded together.

[0024] A preferred embodiment comprises a set of transversal reinforcing steel bars comprising one or more transversal bars for placing in said cuts, wherein the transversal bars comprise upward folds in the upper longitudinal flange for supporting a distribution wire mesh. [0025] In a preferred embodiment, said set of transversal reinforcing steel bars comprises said distribution wire mesh.

[0026] In a preferred embodiment, said transversal bars and said distribution wire mesh are welded together.

[0027] In a preferred embodiment, the profiled sheet and the transversal bars are not welded together.

[0028] In a preferred embodiment, the longitudinally profiled sheet and the transversal bars are arranged perpendicularly to each other.

[0029] In a preferred embodiment, the profiled sheet has a trapezoidal profile.

Brief Description of the Figures

[0030] For an easier understanding, figures are herein attached, which represent preferred embodiments which are not intended to limit the object of the present description.

[0031] Figure 1: Schematic representation of an embodiment of the reinforcement system developed: (a) profiled sheet with longitudinal reinforcement in the upperflange with vertical cuts; (b) transversal bars intersecting the longitudinal stiffener; (c) detail of the bore-shaped cutout in the base of the cut; (d) system integrated in steel-concrete composite slabs.

[0032] Figure 2: Schematic representation of an embodiment of variants of the reinforcement system: (a) and (b) mesh of simple welded wire mesh; (c) and (d) mesh of welded wire mesh for support of the longitudinal reinforcing bars.

[0033] Figure 3: Schematic representation of experimental test: (a) test layout; (b) test specimen after collapse; (c) diagram of bending moments and strength values.

[0034] Figure 4: Schematic representation of tests on continuous steel-concrete composite slabs: (a) test specimen with sheet profile H60 - Test B1-H60; (b) test specimen with transversal bars with a diameter of 10 mm spaced by 400 mm - Test B2 - 010 // 400; (c) R-d curves. Detailed Description

[0035] To demonstrate the effectiveness, a set of experimental tests was carried out in the Laboratory of Structures, Structural Mechanics and Constructions of the Department of Civil Engineering of the University of Coimbra, on steel-concrete composite slabs with the proposed reinforcement system implemented. Figure 3 illustrates one of these tests - steel-concrete composite slab with a span of 2.80 m, width of 820 mm, height of the sheet of 60 mm, height, technically designated thickness, of the slab of 150 mm and with a longitudinal shear reinforcement system consisting of transversal bars with 8 mm diameter spaced by 200 mm along the span, subjected to a loading consisting of 4 linear loads. The load bearing capacity attained was higher than that of a conventional steel- concrete composite slab (H60), and the bending moment attained at half span (38.24 kNm) exceeded the theoretical resistance of the slab in full shear connection (34.75 kNm), obtained based on the nominal values of the geometric and material characteristics of the slab.

[0036] In addition to tests on simply supported steel-concrete composite slabs, two tests were carried out on continuous steel-concrete composite slabs with two spans: (i) test B1 - steel-concrete composite slab with profiled steel sheeting H60; (ii) test B2 - steel-concrete composite slab with transversal bars with a diameter of 10 mm spaced by 400 mm. Figure 4 illustrates the described tests and force-displacement curves obtained in the two tests. The results obtained allow to conclude that the load bearing capacity and ductility of the slab with the proposed reinforcement system (test B2) are significantly higher than those obtained with a conventional slab only with embossments on the steel sheeting (test Bl).

[0037] In a first example, for a better understanding of the efficiency of the system, the load bearing capacity for a conventional steel-concrete composite slab H60 with 1 span and the same slab, but with the proposed reinforcement system with 8 mm diameter bars spaced at 400 mm, was evaluated: i. Steel-concrete composite slabs with 1 span / Simply supported;

ii. Concrete resistance class: C25/30; iii. Steel strength class: SS20 GD + Z;

iv. Sheet thickness: t = 1.0 mm;

v. Partial Connection Method: T U ,R C I = 0.185 MPa.

[0038] Load bearing capacity gains, in percentage terms, for the example in question are indicated in Table 1. It will be seen that when the designing is not governed by deformation (which usually only happens for very high spans and/or thicknesses of slabs very reduced), i.e. for the most common spans of the order of 3 to 5 m, the gains are generally between 20 and 40%.

Table 1 - Resistance increase - Steel-concrete composite slab H60 | t = 1.00 mm |

Transversal bars 08//4OOmm

[00B9] In a second example, the load bearing capacity for a conventional steel-concrete composite slab H60 with 1 span and the same slab, but with the proposed reinforcement system with 10 mm diameter bars in steel A 400 NR, spaced at 250 mm, was evaluated: i. Steel-concrete composite slabs with 1 span / Simply supported;

ii. Concrete resistance class: C30/37;

iii. Steel strength class: S320 GD + Z;

iv. Sheet thickness: t = 1.2 mm;

v. Partial Connection Method: T U ,R C I = 0.185 MPa.

[0040] Load bearing capacity gains, in percentage terms, are indicated in Table 2. Likewise, it will be seen that when the designing is not governed by deformation (which usually only happens for very high spans and/or thicknesses of slabs very reduced), i.e. for the most common spans of the order of 3 to 5 m, the gains range generally from 30 to 60%.

Table 2 - Resistance increase - Steel-concrete composite slab H60 | t = 1.20 mm |

Concrete C30/37 | Transversal bars 01O//25Omm

[0041] The present invention is of course in no way restricted to the embodiments described herein and a person of ordinary skill in the art can foresee many possibilities of modifying it and replacing technical features with equivalents depending on the requirements of each situation as defined in the appended claims. The embodiments described are combinable with each other. The following claims define additional embodiments of the present description.