Auxiliary stiffener and customization of prefabricated trusses using same
View Patent ↗A length-adjustable truss stiffener is intended to be used to strengthen truss systems at locations of localized over-stress to reduce the cost from the alternative solution which is to reduce truss spacings. The stiffener consists of two or more sleeves locking around two or more components of the main truss. The sleeves mounted on different truss components are connected to one another with a length-adjustable shank. The stiffener may be used in two-dimensional or three-dimensional trusses. Of a collection of prefabricated trusses necessary to erect a structure, only a subset of one or more trusses are customized with stiffeners according to loading calculations predicting failure of that subset under required loading conditions, while all other trusses are installed in their original prefabricated state.
1. In combination, a stiffener and an arch-shaped steel truss, said arch-shaped steel truss having a prefabricated form comprised of first and second arcuate chords and a plurality of web members that are welded to and span between said first and second arcuate chords, said stiffener comprising a shank having opposing first and second ends, a first cradle connected to said shank at the first end thereof and shaped to embrace a first portion of the arch-shaped steel truss situated at or adjacent the first arcuate chord on an inner side thereof, and a second cradle connected to said shank at the second end thereof and operable to embrace a second portion of the arch-shaped steel truss situated at or adjacent the second arcuate chord on an inner side thereof; wherein one of the cradles is configured to embrace two adjacent web members of the prefabricated truss at or adjacent a meeting point at which said two web members diverge from one of said arcuate chords.
2. The combination of claim 1 wherein the stiffener further comprises a first cooperating sleeve member fastenable to the first cradle to cooperatively define therewith a first closed sleeve therewith around the first portion of the arch-shaped steel truss.
3. The combination of claim 2 wherein the stiffener further comprises a second cooperating sleeve member fastenable to the second cradle to cooperatively define a closed second sleeve therewith around the second portion of the arch-shaped truss.
4. The combination of claim 2 wherein the first cooperating sleeve member comprises a cradle-shaped central span for embracing about the first portion of the arch-shaped truss, and a respective pair of fastening flanges jut laterally outward from each of the first cradle and the cradle-shaped central span of the cooperating sleeve member for fastening together of the first cradle and the first cooperating sleeve member at the respective fastening flanges thereof.
5. The combination of claim 1 wherein at least one of the first and second cradles resides at an oblique angle to the shank.
6. The combination of claim 1 wherein the first and second cradles are differently configured.
7. The combination of claim 1 wherein said one of the cradles comprises a V-shaped cradle attached to the shank and having two wings that diverge on opposite sides of said shank to respectively embrace the two adjacent web members.
8. The combination of claim 7 wherein the stiffener further comprises a cooperating linear sleeve member configured for fastening the V-shaped cradle in a position embracing the first or second arcuate chord of the arch-shaped steel truss at an outer side thereof opposite the meeting point of the adjacent web members.
9. The combination of claim 7 wherein the stiffener further comprises a pair of cooperating linear sleeve members configured for fastening the V-shaped cradle in positions respectively embracing the adjacent web members on respective opposing sides of the meeting point of said the adjacent web members.
10. The combination of claim 1 wherein the shank is length-adjustable.
11. The combination of claim 10 wherein said shank comprises a screw-based length adjustment mechanism.
12. The combination of claim 11 wherein said screw-based length adjustment mechanism comprises a threaded nut and first and second screw shafts that extend oppositely of one another from said threaded toward the first and second ends of the shank, said first and second screw shafts having opposing left and right handed threads.
13. The combination of claim 1 wherein the first and second cradles are pivotally coupled to the shank to enable variation of an angle between the shank and each of said first and second cradles.
14. In combination, a stiffener and an arch-shaped steel truss, said arch-shaped steel truss having a prefabricated form comprised of first and second arcuate chords and a plurality of web members that are welded to and span between said first and second arcuate chords, said stiffener comprising a shank having opposing first and second ends, a first cradle connected to said shank at the first end thereof and shaped to embrace a first portion of the arch-shaped steel truss situated at or adjacent the first arcuate chord on an inner side thereof, and a second cradle connected to said shank at the second end thereof and operable to embrace a second portion of the arch-shaped steel truss situated at or adjacent the second arcuate chord on an inner side thereof; wherein said shank is one of two shanks spanning between the first and second cradles and laterally spaced from one another so as to span across a webbed area of the arch-shaped steel truss on opposite sides thereof.
15. In combination, a stiffener and an arch-shaped steel truss, said arch-shaped steel truss having a prefabricated form comprised of first and second arcuate chords and a plurality of web members that are welded to and span between said first and second arcuate chords, said stiffener comprising a shank having opposing first and second ends, a first cradle connected to said shank at the first end thereof and shaped to embrace a first portion of the arch-shaped steel truss situated at or adjacent the first arcuate chord on an inner side thereof, and a second cradle connected to said shank at the second end thereof and operable to embrace a second portion of the arch-shaped steel truss situated at or adjacent the second arcuate chord on an inner side thereof; wherein the stiffener further comprises
a second shank to which the second cradle is connected at one end of said second shank; and
a third cradle connected or connectable to said second shank at an opposing end thereof;
wherein the shanks diverge from the second cradle toward the first and third cradles to enable placement of both of said first and third cradles on the first arcuate chord of the arc-shaped truss.
16. A method of customizing an arch-shaped steel truss having a predetermined loading capacity attributed to a prefabricated form of said arch-shaped steel truss that comprises a first arcuate chord, a second arcuate chord and a plurality of existing web members welded to and spanning between said first and second arcuate chords, said method comprising determining load capacity requirements for an intended application of said arch-shaped steel truss, and if said load capacity requirements exceed said predetermined loading capacity, prescribing post-fabrication installation of an auxiliary stiffener to said arch-shaped steel truss in a position bracing against a first portion of the arch-shaped truss situated at or adjacent the first arcuate chord on an inner side thereof, and bracing against a second portion of the arch-shaped truss situated at or adjacent the second arcuate chord on an inner side thereof, in order to augment the existing web members spanning between the first and second arcuate chords of said arch-shaped steel truss, and thereby increase the loading capacity of said arch-shaped steel truss beyond the predetermined loading capacity attributed to the prefabricated form; wherein said auxiliary stiffener comprises a shank having opposing first and second ends, a first cradle connected to said shank at the first end thereof and shaped to brace against the first portion of said arch-shaped steel truss, and a second cradle connected to said shank at the second end thereof and shaped to brace against said second portion of the arch-shaped steel truss, and one of said cradles is configured to embrace two adjacent web members of the arch-shaped steel truss at or adjacent a meeting point at which said two web members diverge from one of said arcuate chords.
17. The method of claim 16 including performing said installation of the auxiliary stiffener on the arch-shaped steel truss.
18. A method of customizing an arch-shaped steel truss having a predetermined loading capacity attributed to a prefabricated form of said arch-shaped steel truss that comprises a first arcuate chord, a second arcuate chord and a plurality of existing web members welded to and spanning between said first and second arcuate chords, said method comprising determining load capacity requirements for an intended application of said arch-shaped steel truss, and if said load capacity requirements exceed said predetermined loading capacity, prescribing post-fabrication installation of an auxiliary stiffener to said arch-shaped steel truss in a position bracing against a first portion of the arch-shaped truss situated at or adjacent the first arcuate chord on an inner side thereof, and bracing against a second portion of the arch-shaped truss situated at or adjacent the second arcuate chord on an inner side thereof, in order to augment the existing web members spanning between the first and second arcuate chords of said arch-shaped steel truss, and thereby increase the loading capacity of said arch-shaped steel truss beyond the predetermined loading capacity attributed to the prefabricated form; wherein the intended application for said arch-shaped steel truss is construction of a new truss-based structure, the arch-shaped steel truss is one of a plurality of identical arch-shaped steel trusses each comprised of the same prefabricated form having the same predetermined load capacity, the step of determining load capacity requirements comprises computer-modelling the truss-based structure based on modeled use of an initially selected quantity of said identical arc-shaped steel trusses and identifying from said modeled use one or more particular trusses of anticipated failure in said truss-based structure, and remodeling a revised iteration of said truss-based structure with a total truss quantity equal to said initially selected quantity, but with at least one of the one or more particular trusses of anticipated failure remodeled as a customized truss equipped with the auxiliary stiffener, and based on said remodeling, determining that construction of said revised iteration of the truss-based structure with at least one of said plurality of arc-shaped trusses equipped with the auxiliary stiffener will meet the loading capacity requirements.
19. The method of claim 18 comprising, after said modelling and remodeling of the truss-based structure, physically installing the auxiliary stiffener on the arch-shaped steel truss.
20. The method of claim 19 comprising, after physically installing the auxiliary stiffener on the arch-shaped steel truss, physically erecting an actual truss-based structure based on the modeled revised iteration of the truss-based structure.
21. The combination of claim 14 wherein the first and second cradles are identical.
22. The combination of claim 15 wherein the second cradle is configured to embrace two adjacent web members of the prefabricated truss at or adjacent a meeting point at which said two web members diverge from one of said arcuate chords.