| JP2006009394 | JOINING STRUCTURE FOR STEEL PIPE |
| JP2000144900 | BUCKLING CONSTRAINT BRACE MATERIAL |
| JP2001288755 | CONSTRUCTION METHOD OF FOOTING |
Hayes, Michael D. (1st floor, Bouhof 31 Robin Hood Road Robindale Randburg 2194, ZA)
| 1. | A structural element for a structure comprising: an angle steel element; and one or more crimped joint regions along the length of the angle steel element, characterised in that where one or more bracing elements is to be joined to the angle steel element a crimped region is pressed into the angle steel element. |
| 2. | A structural element as claimed in claim 1 characterised in that it is manufactured from angle steel. |
| 3. | A structural element as claimed in any one of claims 1 and 2 characterised in that the crimped region of the structural element is reduced to an angle of 60°. |
| 4. | A structural element as claimed in any one of claims 1 to 3 characterised in that the transitional area of the crimped region is supported by the attachment of one or more bracing elements in the transitional area. |
| 5. | A structural element as claimed in any one of claims 1 to 4 characterised in that the crimped region of the joint area decreases the angle of the angle steel structural element thus facilitating a cleatless joint between one or more bracing elements and the structural element. |
| 6. | A method for the manufacture of structural elements for support structures from angle steel elements characterised in that one or more crimped regions along the length of the structural element are pressed into the angle steel element. |
| 7. | A method for the manufacture of structural elements for support structures as claimed in claim 6 characterised in that the crimped region is reduced to an angle of 60°. |
BACKGROUND TO THE INVENTION Structures are known in several different geometric shapes, of most different materials, and for most different application purposes. When the expression structures is used in this patent specification, it is to be understood that this includes trusses between two points of support, pipe bridges, service bridges and more specifically structures used as towers, such as telecommunication or other communication towers.
The Four-legged structures having four structural members are well-known and structural elements in the form of rolled steel angle sections are frequently utilise. These are, however, not suitable when constructing a three-legged tower and the less cost efficient tubular structural elements are therefore used. A further problem associated with the use of tubular structural elements is that whenever maintenance, for example, welding, is carried out in the field damage may be inflicted upon the corrosion proofing, for example, galvanising on the inner surfaces of the tubular structural elements. The damage to the inner surface, being inaccessible to subsequent treatment, results in an increase in corrosion potential and therefore represents a potential problem area. The use of angle steel in the construction of structural elements is also well-known. The angle steel elements provide the advantage of rendering all surfaces accessible to treatment should maintenance be required on the structure in the field. However, a disadvantage of the angle steel element is the necessity of including cleats in
the area of joining bracing members to a support member to permit construction of the joint. This cleat provides an area for potential corrosion to develop and also increases problems associated with maintenance in the field to prevent corrosion. Furthermore, the involvement of a cleat in the construction of the joint increases costs associated with increased material costs and labour costs.
What is ideally required therefore is to make some provision to enable angle steel to be adapted to provide a cost effective means of utilising angle steel in both the structural elements and in bracing members of a lattice bracing in the construction of a structure.
BRIEF DESCRIPTION OF THE INVENTION In accordance with this invention there is provided a structural element for a structure comprising: -an angle steel element; and -one or more crimped joint regions along the length of the angle steel element, arranged such that where one or more bracing members is joined to the angle steel element a crimped region is pressed into the angle steel element thereby decreasing the angle of the angle steel element thus facilitating a cleatless joint between bracing member and support member.
According to a preferred embodiment of the invention there is provided a structural element which is manufactured from angle steel According to a further preferred embodiment of the invention there is provided a structural element for a support structure wherein the crimped joint region is between 90° and 45°, preferably between 80° and 50°, most preferably the crimped region of the steel member is 60°.
Although angle steel without crimping of the joint areas can be used it requires provision to be made for cleats and increased labour for the construction thereof. One means to overcome this is by utilising bent steel which is well-known viz., the steel member is bent to an angle of 60° from the angle steel which is original a 90° rolled steel member. The bending of the 90° steel member requires access to large presses to effect the bend throughout the length of the member. The presses capable of effecting such bending are expensive and, obviously, not practical for purposes of use in the field. These limitations can be overcome by effecting a crimping of the localise regions in the area of the joint between the lattice bracing members and the support members of the structure. Since these particular presses are less cumbersome than those required for effecting a bending throughout the steel member's length they can, if necessary, be used under field conditions, and are also more cost effective.
Furthermore, in accordance with this invention there is provided a method for the manufacture of structural members for support structures from angle steel elements wherein one or more crimped regions along the length of the structural member are pressed into the angle steel element.
BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the invention more clearly, the invention will now be described by way of example with reference to what is set out hereunder. In the drawings:- Figure 1 is a sectional plan A-A of a joint region between bracing members and the structural element according to the invention; Figure 2 is a side elevation of a joint region between bracing members and the structural element according to the invention; Figure 3 is a side elevation of a joint region between bracing members and the structural element according to the invention;
Figure 4 is a side elevation plan of a joint region between bracing members and a support according to one form of the prior art; Figure 5 is a section plan of a joint region between bracing members and a support according to one form of the prior art; Figure 6 is a sectional plan of a crimped region of the structural element showing the decreased angle in the crimped region; Figure 7 is a side elevation of a telecommunication or other tower according to the invention; Figures 8 and 9 show a plan view of a telecommunication or other tower according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS In one form of the invention, as shown in Figure 1 and 2, a structural element 10 is shown with two bracing members 12 and 14 joined to the structural element 10. The crimped region 16 (as shown in Figure 2) of the structural element 10 changes from 90° in the uncrimped regions of the support member 22 and 24 through the transitional areas 18 and 20 to an angle of 60° in the crimped region 16. The bracing members simply require cropping and punching to fit the crimped region 16 of the structural element 10.
According to further aspect of the present invention as shown in Figure 3, a joint region is shown before cropping and punching of the bracing members 12 and 14 has taken place. Structural element 10 is shown before crimping of the joint area 16 has been effected.
Figures 4 and 5 show a joint 26 according to one form of the prior art with cleats 30 (shown in Figure 5) to which the bracing members (not shown) are attache. The cleats 30 are attached to the support member 32 by way of a plurality of bolts 28.
Figure 6 shows a sectional plan of an angle steel structural element 36 with the original 90° angle before crimping reduces the angle to the angle of 60 ° for the crimped region 34.
Figure 7 shows a side elevation of a three-legged telecommunication tower 70 with lattice bracing 72 joined to the structural element 74 of the tower 70.
Figures 8 and 9 show plan views of the three-legged tower illustrated in Figure 7 It will be immediately apparent to any person skilled in the art that although certain embodiments only of the invention have been set out herein, other modifications and/or variations of the invention are possible. Such modifications and/or variations are to be considered as falling within the spirit and scope of the present invention.
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