Structural fuses are known for use in homes, buildings and other structures for dissipating stresses in the structural connections and frames upon seismic, wind or other loads on the structures. For example, the Yield-Link® structural fuse from Simpson Strong-Tie, Pleasanton, Calif., may be used at a connection of a beam to a column so that, when loads on the structural connection reach a threshold, the structural fuse yields to dissipate energy without damage to the beam or column. Thereafter, the damaged structural fuse may be removed and replaced without having to otherwise repair the connection.
A typical structural fuse includes a base and a plate welded orthogonally to the base. The plate may include a midsection having a small diameter than ends of the plate, the midsection designed to be the area where yielding occurs. In use, the base may be bolted to a column. A first surface of the yield plate may rest against a surface of the beam, with an end of the yield plate bolted to the beam. A planar buckling restraint plate (BRP) on a second surface of the yield plate, opposite the first surface, may be bolted through the yield plate and into the beam to prevent buckling of the plate under compressive loads. Spacers may be provided in the smaller diameter midsection of the yield plate to evenly distribute loads on the plate and the BRP, when the BRP is bolted to the beam.
Currently, the fuse base, fuse yield plate, buckling restraint plate and spacers are all formed from different pieces of steel, each having different properties. Moreover, welding of the fuse base to the fuse plate needs to be a complete joint penetration (CJP) weld, which are difficult welds to perform and subject to imperfections. Even if done correctly, the weld is less ductile than the other portions of steel in the structural fuse, and can abruptly fail before yielding of the structural fuse at the midsection.
The present technology relates to a one-piece structural fuse assembly formed from a single piece of structural steel such as an I-beam or standard structural W-shape beam. Initially, a section, or blank, may be cut from a beam. The blank may be severed transverse to the length of the beam, so that the blank includes first and second flanges connected by a web. In embodiments, the first flange of the blank may form the fuse base, and a portion of the web of the blank may form the fuse yield plate. Additionally, in embodiments, the buckling restraint plate may be formed from the second flange of the blank, and the spacers may be formed from a portion of the web unused in the fuse yield plate. In embodiments, all of the components cut from the single blank are used in a single structural fuse assembly.
In one example, the present technology relates to a pair of structural fuse assemblies, comprising: a first blank taken from a first section of beam, the first blank comprising: a first structural fuse comprising; a first fuse base formed from a first flange of the beam, a first fuse yield plate extending from and integrally formed with the fuse base, the fuse plate formed from a web of the beam, and the fuse yield plate comprising a narrow area defined by a pair of notches; a first pair of spacers formed from the web of the beam and configured to fit within the pair of notches; and a first buckling restraint plate formed from a second flange of the beam; and a second blank taken from a second section of beam, the second blank comprising: a second structural fuse comprising; a second fuse base formed from the first flange of the beam, a second fuse yield plate extending from and integrally formed with the fuse base, the fuse plate formed from a web of the beam, and the fuse yield plate comprising a narrow area defined by a pair of notches; a second pair of spacers formed from the web of the beam and configured to fit within the pair of notches; and a second buckling restraint plate formed from a second flange of the beam; wherein the first and second sections of beam are directly adjacent each other on the beam.
In another example, the present technology relates to a structural fuse assembly, comprising: a structural fuse comprising; a fuse base, a fuse yield plate extending from and integrally formed with the fuse base, the fuse yield plate comprising a narrow area defined by a pair of notches; a pair of spacers for fitting within the pair of notches; and a buckling restraint plate; wherein the structural fuse, the pair of spacers and the buckling restraint plate all come from a single section of a structural steel component.
In a further example, the present technology relates to a structural fuse assembly, comprising: a blank taken from a section of a beam, the blank comprising: a structural fuse comprising; a fuse base formed from a first flange of the beam, a fuse yield plate extending from and integrally formed with the fuse base, the fuse plate formed from a web of the beam, and the fuse yield plate comprising a narrow area defined by a pair of notches; a pair of spacers formed from the web of the beam and configured to fit within the pair of notches; and a buckling restraint plate formed from a second flange of the beam.
In another example, the present technology relates to a structural fuse assembly, comprising: a blank taken from a section of a beam, the blank comprising: a structural fuse comprising; a fuse base formed from a first flange of the beam, and a fuse yield plate extending from and integrally formed with the fuse base, the fuse plate formed from a web of the beam.
In a further example, the present technology relates to a method of fabricating a structural fuse assembly, the method comprising: (a) cutting a blank from a structural steel component including at least a first flange and a web extending orthogonally from the first flange and integrally formed with the first flange; (b) forming the first flange of the blank into a fuse base of the structural fuse assembly; and (c) forming the web of the blank into a fuse yield plate of the structural fuse assembly.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.
The present technology, roughly described, relates to a one-piece structural fuse assembly formed from a single piece of structural steel such as an I-beam, a wide-flange I-beam or a standard structural W-shaped beam. The structural fuse assembly may include a structural fuse having a fuse base and a fuse plate, a pair of spacers and a buckling restraint plate (BRP). Initially, a blank may be cut from a beam transverse to the length of the beam, so that the blank includes first and second flanges connected by a web. In embodiments, the first flange of the blank may form the fuse base, and a portion of the web of the blank may form the fuse plate. Additionally, in embodiments, the BRP may be formed from the second flange of the blank, and the spacers may be formed from a portion of the web unused in the fuse plate. In embodiments, all of the components cut from the single blank are used in a single structural fuse assembly.
Forming some or all of the components used in a structural fuse assembly from a single piece of a beam provides several advantages. First, having the fuse base integrally formed with the fuse plate avoids the need for a complete joint penetration weld, thus removing the possibility of human error in forming the weld, and brittleness at the weld site. Second, it is important that the spacers be the same thickness as the fuse plate to within a tight tolerance, such as for example 0.15 inches. Forming the spacers and the fuse plate from the same web ensures this tight tolerance is met. Third, when steel is heated in a certain way, a grain of the steel may align to polar north. Forming the structural fuse assembly from a piece of steel where all of the grain is aligned ensures uniform properties and response across the entire structural fuse assembly.
It is understood that the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the invention to those skilled in the art. Indeed, the invention is intended to cover alternatives, modifications and equivalents of these embodiments, which are included within the scope and spirit of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be clear to those of ordinary skill in the art that the present invention may be practiced without such specific details.
The terms “top” and “bottom,” “upper” and “lower” and “vertical” and “horizontal” as may be used herein are by way of example and illustrative purposes only, and are not meant to limit the description of the invention inasmuch as the referenced item can be exchanged in position and orientation. Also, as used herein, the terms “substantially” and/or “about” mean that the specified dimension or parameter may be varied within an acceptable manufacturing tolerance for a given application. In one embodiment, the acceptable manufacturing tolerance is ±0.25%.
The flanges may be formed in a so-called standard structural W-shape, where interior surfaces 202a, 204a of the flanges 202 and 204 are orthogonal to the surfaces of the web 206 (
In step 100, a section of the beam 200 is cut from the beam in a direction transverse to a length (L,
In step 102, a first transverse cut is made adjacent to the second flange 204 to separate the flange 204 from the web 206 (
In step 110, bolt holes may be formed in the first flange 202, the second flange 204, the web 206 and/or the section 214. For example, as shown in
In step 114, portions 230 may be removed from web 206 to define notches 232 (
In step 118, section 214 may be cut in half to define a pair of spacers 242 and 244 (
In the embodiment described above, the spacers 242 and 244 are taken from a section of the web 206 beyond the end of the fuse yield plate 238. However, in a further embodiment shown in
After formation of the structural fuse 240, spacers 242, 244 and BRP 246, all parts may be cleaned and painted or powder coated, for example with PMS 172 orange, in step 122. Step 122 may include blasting the respective components to remove any slag from plasma or other elevated temperature cutting processes. It may also remove scale which may result from the rolling fabrication process of the beam 200. The cleaning step 122 may also remove rust from the components 240, 242, 244 and 246.
Possibly depending on the type of process used to form the structural fuse 240, spacers 242, 244 and BRP 246, is understood that a number of the above-described steps may be performed in a different order. For example, it is understood that the sequence of steps including the first transverse cut (step 102), the second transverse cut (step 106), the formation of the bolt holes (step 110), and the formation of the notches (step 114) maybe performed in any order in further embodiments.
As noted, one process for forming the structural fuse 240, spacers 242, 244 and BRP 246 may involve plasma cutting and hole forming.
In step 164, a second transverse cut is made at an end portion of web 206 to substantially separate the section 214 from the web 206. In particular, a second small tab may be left connecting the end portion to the web 206 after the second transverse cut is completed. Thus, the second flange remains attached to the end portion by the first tab, and the end portion remains attached to the web by the second tab. A reason for the use of the tabs to maintain the blank as a single piece after the first and second transverse cuts is so that a technician does not need to retrieve severed pieces from the elevated temperature plasma cutting equipment. As explained below with reference to
In step 168, the notches may be cut in the web 206 to define the narrow width area 234 shown in
In step 176, the BRP 246 may be milled to remove any remnants of the web 206 to form the BRP into a planar plate, and the bolt holes may be formed in the BRP. Thereafter, in a step 178, the structural fuse 140, the spacers 242, 244 and the BRP 246 may optionally be painted.
As shown in
In embodiments, the structural fuse assembly 300 further includes the BRP 246 and the pair of spacers 242, 244 (one of which is omitted from
In order to affix a structural fuse assembly 300 between a beam 250 and column 252, the fuse base 236 may initially be affixed to the column 252, either at the jobsite or remote from the jobsite. As noted above, the fuse base 236 may include bolt holes 220 (
Thereafter, at the jobsite, the beam-mounted fuse yield plate 238 may be bolted to the beam 250 via a plurality of bolts 312 (one of which is shown in
The BRP 246 may next affixed to beam 250 over the narrow width area 234 of the fuse yield plate 238. As seen for example in
The respective structural fuse assemblies 300 shown in
It is understood that the components of the structural fuse assembly 300 may have different dimensions within the scope of the present technology. However, the following are examples of some dimensions. The fuse base may have a length of 12 inches, and a width of 10 inches. The fuse yield plate may extend from the fuse base halfway along the width of the fuse base. To the extent the final width of the fuse base differs from the width of the beam 200 from which the fuse base comes, unused portions of the beam 200 above and below the width of the fuse base may be cut and discarded, for example by CNC plasma cutting.
The fuse yield plate may have a width of 12 inches and a length of 36 inches. The narrow width areas 234 may be spaced 6 inches from the fuse base, and may have a length of 12 inches. The narrow width areas 234 may have a width of 6 inches. The spacers 242, 244 may be any length and width that fill at least a substantial portion of the notches defined by the narrow width areas 234. The BRP 246 may have a length and width of 12 inches. As mentioned, each of the above dimensions may vary, proportionately and disproportionately with each other, in further embodiments of the technology.
In embodiments, all components in a structural fuse assembly 300 may come from the same blank 210. Thus, in embodiments where a structural fuse assembly 300 comprises a structural fuse 240, spacers 242, 244 and BRP 246, each may come from the same blank 210. In embodiments where a structural fuse assembly 300 comprises a structural fuse 240 and spacers 242, 244, each may come from the same blank 210 (with the BRP 246 coming from another blank or other structural component). In embodiments where a structural fuse assembly 300 comprises a structural fuse 240 and BRP 246, each may come from the same blank 210 (with the spacers 242, 244 coming from another blank or other structural component). In embodiments where the structural fuse 300 comprises a structural fuse 240 alone, the spacers 242, 244 and/or BRP 246 may come from another blank or other structural component.
In fabrication, multiple blanks 210 may be cut from a length of beam 200. The components from each blank (a structural fuse 240, spacers 242, 244 and/or BRP 246) may each be uniquely marked, or otherwise separated/distinguished from the components coming from another blank 210, to ensure components from a single blank are used together in a finished structural fuse assembly 300.
In embodiments, structural fuse assemblies 300 from blanks 210 taken from anywhere on a beam may be used as the top and bottom assemblies 300 shown in
An embodiment in which adjacent blanks 210 may be used together at the top and bottom of a beam/column connection is shown for example in
As noted above, when steel is heated to at least a predefined temperature, crystals in the steel can align in the same direction to give the steel a grain. It is an advantage of the present technology that the grain of components used in the structural fuse assembly 300 may be aligned with each other.
The foregoing detailed description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.