Patent EA-002344-B1 (EA)
Title: Cellular stirrups and ties for structural members
IPC: E04C5/06
Filed: 1998-11-04
Abstract: 1. Stirrup or tie for the reinforcement of structural members, comprising a load bearing element (20, 30) to receive the rebars (10) of the reinforcement, whereby the load bearing element (20, 30) a) forms at least one plane cell of closed shape (50) with an inner periphery to receive the rebars (10) of the reinforcement, which are arranged on at least two planes, and b) has a continuous cross-section to carry the axial tensile force developed when the structural member is loaded, so that the flow of the tensile stresses developed in the cross-section of the load bearing element (20, 30) is closed and is not transmitted to the surroundings of the stirrup or tie. 2. Stirrup or tie for the reinforcement of concrete structural members according to claim 1, whereby the load-bearing element has a solid cross-section. 3. Stirrup or tie for the reinforcement of concrete structural members according to claim 1 or 2, whereby the stirrup or tie does not have any means to anchor the stirrup to the concrete, so that the axial force developed in the cross-section of the load bearing element is not transmitted to the surroundings of the stirrup or tie. 4. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 3, whereby the stirrup or tie consists of more than one load bearing elements (20) and that each one of the load bearing elements (20) consists of one cell of closed shape (50) so that the flow of the tensile stresses developed in the cross-section of each one of the load bearing elements (20) is closed and it is not transmitted to the concrete. 5. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 4, whereby the load-bearing element has a curved shape. 6. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 4, whereby the load bearing element has a rectangular shape. 7. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 6, whereby the load bearing element (30) consists of more than one cells of closed shape (50) so that the flow of the tensile stresses developed in the cross-section of the bearing element (30) is closed and it is not transmitted to the surroundings of the stirrup or tie. 8. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 7, whereby the inner periphery of the load bearing element has means (26,72) to receive the rebars (10). 9. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 8, whereby the stirrup or tie comprises bipolar wires (71) for fastening the rebars (10) on the load bearing element (20, 30). 10. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 9, whereby the stirrup or tie is metallic. 11. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 9, whereby the stirrup or tie is made of composites. 12. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 11, whereby the load bearing elements are cast. 13. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 12, whereby the cross-section of one or more bearing elements (20, 30) is variable. 14. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 13, whereby the cross-section of the load-bearing element may carry safely a 100 N tensile load. 15. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 14, whereby the stirrup or tie comprises bores (73) to receive auxiliary installation bars. 16. Stirrup or tie for the reinforcement of concrete structural members according to any of the claims 1 to 15, whereby protrusions (74) are provided along the load-bearing element. 17. Reinforcement for concrete structural members, which consists of longitudinal rebars (10) and stirrups or ties according to any of the claims 1 to 16, connected with the rebars (10) transversely or at an angle. 18. Reinforcement for concrete structural members according to claim 17, whereby the reinforcement is prefabricated. 19. Method for construction of a concrete structural member comprising the following steps: - constructing of a framework (14), - providing longitudinal rebars (10),  - attaching the rebars (10) to stirrups or ties, which stirrups or ties comprise a load bearing element (20, 30) to receive the rebars (10) of the reinforcement, whereby the load bearing element (20, 30) which  a) forms at least one plane cell of closed shape (50) with an inner periphery to receive the rebars (10) of the reinforcement, which are arranged on at least two planes, and b) has a continuous cross-section to carry the axial tensile force developed when the structural member is loaded, so that the flow of the tensile stresses developed in the cross-section of the load bearing element (20, 30) is closed and is not transmitted to the surroundings of the stirrup or tie, and - casting of concrete in the framework (14) and covering the longitudinal rebars (10) and the stirrups or ties by the concrete. 20. Method for construction of a concrete structural member according to claim 19, whereby the stirrups or ties are according to any of the claims 1 to 16. 21. Concrete structural member which consists of longitudinal rebars (10), stirrups or ties, which interact with the rebars, and concrete, which surrounds both the rebars (10) and the stirrups or ties, whereby the stirrups or ties comprise a load bearing element (20, 30) to receive the rebars (10) of the reinforcement, and whereby the load bearing element (20, 30) a) forms at least one plane cell of closed shape (50) with an inner periphery to receive the rebars (10) of the reinforcement, which are arranged on at least two planes and b) has a continuous cross-section to carry the axial tensile force developed when the structural member is loaded, so that the flow of the tensile stresses developed in the cross-section of the load bearing element (20, 30) is closed and is not transmitted to the surroundings of the stirrup or tie.