Seismic bracing yield fuse

A seismic bracing yield fuse includes at least one housing member, and a fuse member housed within or mounted externally to the at least one housing member. The fuse member is configured to undergo ductile yielding in a length dimension upon application of a tensile force along the length dimension of the fuse member, and the at least one housing member is configured to accommodate a change in length of the fuse member resulting from the ductile yielding.

TECHNICAL FIELD

The present disclosure relates generally to bracing for using in supporting nonstructural equipment from a structural member of a building. In particular, the present disclosure relates to seismic bracing for use applications, and yield fuses for use in seismic bracing.

BACKGROUND

Until the adoption of the 2012 International Building Code (IBC), which refers to the American Society of Civil Engineers (ASCE) document 7-10, the standard methodology for designing seismic braces to nonstructural items was to restrain these systems with either rigid braces or cable braces that were designed to have sufficient strength to resist seismic forces calculated based on ASCE 7-10 requirements. “Nonstructural” refers to systems other than the building structural systems (such as walls, beams, columns, building braces) themselves. Nonstructural items include piping systems, mechanical ductwork, electrical conduit and cable trays, and mechanical or electrical systems that are attached to the structure, but not part of the structure itself. It is anticipated that an Omega value concept will remain in the building code, as the structural engineering profession regards ductile yielding to be an important component of good seismic performance of structural components of buildings and more recently also nonstructural components within buildings

The relative strength of brace components (i.e., the nonstructural brace itself, the nonstructural brace attachment to the nonstructural item, and the nonstructural brace attachment to the structure) is not specifically evaluated. Rather, if the brace assembly as a whole has sufficient strength and stiffness, the brace met pre-2012 IBC requirements. Beginning with the 2012 IBC, a factor referred to as “Omega” was implemented regarding the relative strength of anchors to concrete in comparison to nonstructural brace strength. This Omega factor requirement states that the force used in seismic anchor design to concrete must be increased by a factor of 2.5 unless it can be demonstrated that the connection to the structure provides ductile yielding. Since prior to the 2012 IBC requirements commercially available brace connections had been designed to be strong and rigid with respect to nonstructural brace and anchor strength, commercially available bracing products under the 2012 IBC requirements now require multiplying the anchor force by 2.5 or 250%. Building structures themselves have had similar requirements added in preceding codes beginning in the late 1990s, resulting in the development of energy absorbing ductile connection devices for large systems in building braces and beam to column assembles. These assemblies are not usable for nonstructural items due to their large size and use of heavy steel assemblies or concrete-filled tube assemblies.

For the foregoing reasons, there is a need to provide improved supports and bracing for nonstructural items that are lightweight, compact and usable with existing commercial products.

SUMMARY

The present disclosure is directed to supports and bracing for use with nonstructural items in a building. Such supports typically provide connection of a nonstructural item to a structural member (e.g., a ceiling) of a building, wall or other structural component of the building. The present disclosure may relate particularly to seismic bracing for nonstructural items, and yield fuses for use with seismic bracing.

The seismic bracing generally, and the yield fuse specifically, typically includes a lightweight, compact assembly that weighs ounces (at most less than 1-2 pounds) rather than much larger bracing that is typical for bracing used with structural features of a building. The yield fuses disclosed herein typically can be used with the many already available commercial bracing products. In one embodiment, the connection devices typically weigh between a few ounces and a pound, although larger and smaller versions are possible. The yield fuses may have several configurations to adapt to many different bracing systems. Of note, the yield fuses may permit the use of Omega=1.0 instead of Omega=2.5 as is required by the 2012 IBC requirements described above. This is achieved by the use of a ductile-yielding nonstructural brace fuse in the seismic bracing. The fuse may have any of a variety of configurations that permit some yielding under certain load conditions (e.g., a seismic event). One configuration includes a yielding “dog-bone” shaped fuse member. Another configuration includes a yielding corrugated strip fuse member. A further configuration includes at least one yielding pin fuse member. These and other configurations of the present disclosure may reduce the required anchor forces by 250% and may also provide superior brace performance by yielding of the brace fuse, rather than sudden brittle failure of either the brace anchor or the brace connectors.

Another aspect of the present disclosure relates to a seismic bracing yield fuse that includes at least one housing member and a fuse member. The fuse member is housed within or mounted externally to the at least one housing member. The fuse member is configured to undergo ductile yielding in a length dimension upon application of a tensile force along the length dimension of the fuse member. The at least one housing member is configured to accommodate a change in length of the fuse member resulting from the ductile yielding.

The fuse member may have a dog bone shape. The fuse member may have a reduced width at a location spaced between opposing ends of the fuse member. The fuse member may include a corrugated structure. The fuse member may include a rod-shaped member that is mounted to an exterior surface of the at least one housing member. The at least one housing member may have a single-piece construction and apertures formed therethrough at opposing ends of the housing member. At least one of the apertures may have a slot shape, and the fuse member may have apertures formed therethrough at opposing ends that are aligned with the housing apertures and receptive of connection features. The slot-shaped aperture may accommodate the change in length of the fuse member resulting from the ductile yielding.

The at least one housing member may include a first housing member at least partially inserted into and slidable relative to a second housing member. The seismic bracing yield fuse may also include a backup wire extending between and securing together the first and second housing members as an assembly. The seismic bracing yield fuse may include a connector bracket mounted to the fuse member and the at least one housing member. The fuse member may include a material having a different ductility than material of the at least one housing. The fuse member may have a higher ductility than a connecting member to which the seismic bracing yield fuse is connected. The at least one housing member may include an integrally formed angled portion extending from an end thereof. The at least one housing member may have a rectangular cross-sectional shape.

Another aspect of the present disclosure relates to a seismic bracing yield fuse that includes a housing assembly and a fuse member. The housing assembly includes a first housing member and a second housing member at least partially insertable into the second housing member. The fuse member is positionable within the housing assembly or mounted to the housing. The fuse member has an elongate construction and is plasticly deformable in a length dimension upon application of a force.

The housing assembly may include housing connector apertures formed in opposing ends thereof, wherein the housing connector apertures are receptive of connection members to connect the seismic bracing yield fuse to a non-structural item. The non-structural item may include at least one of piping systems, mechanical ductwork, electrical conduit and cable trays, and mechanical or electrical systems. The fuse member may include fuse connector apertures formed in opposing ends thereof, wherein the housing apertures are aligned with the fuse connector apertures and receptive of the connection members. The first and second housing members may each include mounting tabs positioned on exterior surfaces thereof, wherein the mounting tabs are configured to mount the fuse member to the housing assembly. The seismic bracing yield fuse may include first and second fuse members arranged in parallel and mounted to exterior surfaces of the fuse assembly.

A further aspect of the present disclosure relates to a method of assembling a seismic bracing yield fuse. The method includes providing a housing assembly and a fuse member, the fuse member being configured to undergo ductile yielding in a length dimension upon application of a tensile force along the length dimension of the fuse member, mounting the fuse member internal the housing assembly or to an exterior of the housing assembly, and providing connection features to secure opposing ends of the fuse member to a connection assembly for application of the tensile force.

Another aspect of the present disclosure relates to a method of providing a ductile yield in a connection assembly that supports nonstructural equipment from a structural member of a building. The method includes providing a seismic bracing yield fuse having a housing and a fuse member, connecting the seismic bracing yield fuse in series between the structural member and the nonstructural equipment, and applying a tensile force to the fuse member until the fuse member undergoes ductile yielding.

DETAILED DESCRIPTION

The present disclosure is directed to bracing and/or connecting devices for use in supporting nonstructural items from a structural member in a building. Such structural members, when formed from concrete, may include concrete flat slabs, concrete waffle slabs, concrete panel slabs, concrete over metal deck, concrete beams, or concrete columns within aa building or facility. The fuse device may also be used when attaching nonstructural seismic bracing to other structural members, such as masonry walls, steel beams, steel columns, steel trusses, metal grating, or any other structural member that comprises the building or structure itself. A fuse member may be used as part of the bracing to support the nonstructural item from the structural member of the building. The fuse may be characterized as a seismic bracing yield fuse at least in part because the bracing is used as a bracing member to support the nonstructural item from a structural member of a building in the event of a seismic event. The yield fuse may refer to the fuse being configured to yield when a load above a threshold amount is applied to the seismic bracing and/or fuse, such as during a seismic event. The use of a yielding fuse may permit use of an Omega factor of 1.0 rather than the otherwise required Omega factor of 2.5 under the 2012 IBC requirements discussed above.

The embodiments for a seismic bracing yield fuse disclosed herein with reference to the figures are exemplary only. The general principles applicable to these yield fuses may be used in other related embodiments and designs to help avoid the need to use an Omega factor of 2.5 under the 2012 IBC requirements. As discussed above, using an Omega factor of 1.0 greatly enhances a designer's ability to create a seismic bracing design that is cost-effective and meets practical size and weight limitations associated with supporting nonstructural items in a building.

Refer now toFIGS.1and2, an example of seismic bracing yield fuse10is shown and described. The seismic bracing yield fuse10includes a fuse member12(shown inFIG.2), a housing assembly14, a first connector member16(e.g., wire), a second connector member18(e.g., bracket), and a fastener19used to secure the second connector member18to the housing assembly14. The fastener19may be a bolt, screw, rivet or other fastener. The second connector18may include an aperture17to receive the fastener19as shown inFIG.2.

Referring toFIG.2, the fuse member12includes first and second ends20,22, first and second fuse apertures24,26, and a reduced width portion28. The fuse member12has a width W1in the area adjacent to the first and second fuse apertures24,26, a length L1between the first and second fuse apertures24,26, a thickness T1, and a reduced width W2in the area of the reduced width portion28at a location spaced between the first and second apertures24,26. The fuse member12may be referred to as having a dog bone shape. The limited amount of material in the reduced width portion28as compared to other locations along the length of the fuse member12may result in the fuse member12yielding first in the area of the reduced width portion28upon application of a tensile load or force along the length of the fuse member12. The tensile load may be applied via the first and second apertures24,26. The first and second connector members16,18may be mounted to the fuse member12via the first and second fuse apertures24,26. The yielding of the fuse member12may result in an elongation of the fuse member12, thereby increasing the length L1. The amount of tensile force applied to the fuse member12typically is insufficient to elongate the fuse member12to the point of failure (i.e., the fuse member12breaking into two pieces).

The housing assembly14includes first and second housing members34,36that have respective first and second housing apertures38,40. The housing members34,36include a closed end42,44, respectively, and an open end46,48, respectively. The first housing member34defines an internal cavity sized to receive the second housing member36in a sliding engagement as shown inFIG.1. The internal cavities of both the first and second housing members34,36are sized to receive portions of the fuse member12. The sliding arrangement between the first and second housing members34,36permits relative movement such that a spacing between the first and second housing apertures38,40(length L2) may vary depending on changes in the length of fuse member12.

When assembled, the seismic bracing yield fuse10provides for the first fuse aperture24to be aligned with the first housing aperture38, the second fuse aperture26to be aligned with the second housing aperture40, the first connector member16to extend through the apertures26,36, and the fastener19to extend through the first apertures24,34to secure the second connector member18to the housing assembly14. The second connector member18extends beyond the closed end42of the first housing member34. The second connector member18may have a bent or angled shape and an aperture21to promote connection of the seismic bracing yield fuse10to a nonstructural item or to nonstructural ceiling mount or connector as shown inFIGS.15and15A. For example, the second connector member18may be secured to a seismic ceiling mount82that is secured to a ceiling80of a building. The first connector member16may be connected to a nonstructural item84via a nonstructural ceiling connector88. The nonstructural item84may be secured to the ceiling80with a nonstructural ceiling mount86. Typically, the nonstructural item84is secured to the ceiling80with two nonstructural ceiling mounts86and two seismic bracing yield fuses10that are part of a seismic bracing assembly90.

Refer now toFIGS.3and4, another example seismic bracing yield fuse100is shown and described. The seismic bracing yield fuse100includes many of the same or similar features as described above with reference to seismic bracing yield fuse10but with the second connector member integrated into the housing assembly.

The seismic bracing yield fuse100includes a fuse member112, a housing assembly114, first and second connector members16,18, and a fastener19. The fuse member112includes first and second ends120,122, first and second fuse apertures124,126, and a reduced width portion128. Generally, the fuse member112has the same or similar construction as the fuse member12described above with reference toFIGS.1and2. The housing assembly114includes first and second housing members134,136, first and second housing apertures138,140, closed ends142,144, and open ends146,148. The first housing member134as shown inFIG.14includes an extension150having an extension aperture152. A length L2between the apertures138,140may be the same or similar to a length L1between the apertures124,126of the fuse member12prior to application of a tensile force to the fuse member112that causes yielding (i.e., increasing in the length of L1). The length L2may change by relative movement of the first and second housing members134,136via the sliding engagement therebetween.

FIG.16illustrates the seismic bracing yield fuse100in an environment where a nonstructural item84is mounted to a ceiling80of the building structure.FIG.16ais a closeup view of the seismic bracing yield fuse100as part of a seismic bracing assembly190. The first housing member134is connected to a seismic ceiling mount82via the extension150and aperture152. The extension150may be hollow like remaining portions of the first housing member134. In other embodiments, the extension150has a solid construction to provide improved strength and durability at the connection point to the seismic ceiling mount82.

The seismic bracing yield fuse100may have advantages over the embodiments shown inFIGS.1and2. For example, the seismic bracing yield fuse100may include fewer parts, thereby requiring less assembly time, storage, and the like as compared to the embodiments shown inFIGS.1and2. Other advantages may also be possible [Inventors, please provide any insights here about advantages].

FIGS.5and6illustrate another example seismic bracing yield fuse200that includes the seismic bracing yield fuse10with an additional backup wire202. The backup wire202includes first and second wire connectors204,206positioned at opposing ends as shown inFIG.6. The first wire connector204is configured to align with the fuse aperture24, housing aperture38, and aperture17of the second connector18through which the fastener19is inserted to provide an assembly of those parts. The second wire connector206is configured to align with the second fuse aperture26and the second housing aperture40and be receptive of the first connector member16to provide assembly of those parts as shown inFIG.5. The backup wire202may function as a safety measure to ensure that the assembly of parts of the seismic bracing yield fuse, in particular the assembly of the housing members34,36remains intact in the event that there is failure of the fuse member12.

The backup wire202may comprise a wire having the same or greater strength than, for example, the first connector member16. The backup wire202may be flexible along its length to permit relative movement between the first and second housing members34,36, such as during yielding of the fuse member12. The backup wire202may have a length L3between the apertures of the first and second wire connectors204,206as shown inFIG.6. The length L3may be greater than length L1and length L2, and may be greater than any length L1that is possible up to the point of failure of the fuse member12. In some embodiments, the length L3is sufficient short to prevent yielding of the fuse member12to a point of failure, such as a length L3that is equal to or less than the length L1achieved prior to the point of failure of the fuse member12.

The first and second wire connectors204,206may be formed integral as a single piece with a wire portion203of the backup wire202. In other embodiments, the first and second wire connectors204,206may be formed as separate connector members that are secured to the wire portion203in a later assembly step, such as by welding or the like.

The backup wire202may be used with any of the embodiments disclosed herein to provide an improved safety constraint that prevents disassembly of the seismic bracing yield fuse in the event of the fuse member failing. In the applications shown inFIGS.15and16, the backup wire202may prevent disconnection of the seismic ceiling mount82from the first connector member16.

FIGS.7and8illustrate another example seismic bracing yield fuse300having a fuse member312, a housing assembly314, a first connector member16, a second connector member18, and a fastener19used to connect the second connector member18via an aperture17.

The fuse member312is shown having the same or similar construction as the dog bone shaped fuse member12,112described above with reference toFIGS.1-6. The housing assembly314has a single-piece construction with a closed end342and an open end346and first and second housing apertures338,340. The apertures338,340may have a slot-shaped construction, also referred to as an elongate shape or oval shape. The spacing between the apertures338,340may have a length L2. The shape of the apertures338,340may accommodate changes in the length L1between apertures324,326of the fuse member312. The change in length L1may occur as a result of yielding of the fuse member312under application of a tensile force along the length of the fuse member312, such as during a seismic event when the seismic bracing yield fuse300is used with bracing for a nonstructural item within a building (e.g., the environments shown inFIGS.15and16).

Use of a single housing member may have advantages over the multi-piece housing assemblies described above with reference toFIGS.1-6. For example, a seismic bracing yield fuse having a single piece housing member requires fewer parts, reduced assembly time, and a reduced risk of the first and second connector members16,18becoming disconnected from each other in the event the fuse member312fails. [Inventors, are there other advantages for this embodiment?]

FIGS.9and10illustrate another example seismic bracing yield fuse400that includes a fuse member412, a housing assembly414, and a first connector member16.FIGS.11and12illustrate the seismic bracing yield fuse400with a second connector member18having an aperture17, and a fastener19to secure the second connector18to the other components of the seismic bracing yield fuse400.

The fuse member412may have a different configuration and provide a different function as compared to the dog bone-shaped fuse member included in the embodiments disclosed above with reference toFIGS.1-8. The fuse member412may include first and second ends420,422, first and second fuse apertures424,426, a corrugated portion430having a width W3, a length L1between the apertures424,426, a width W1near the apertures424,426, and a thickness T1.

The housing assembly414includes first and second housing members434,436, first and second housing apertures438,440, closed ends442,444, and open ends446,448. The housing assembly414may have many of the same or similar features as the housing assembly14described above. When assembled, the apertures424,426are aligned with the apertures438,440of the housing assembly414and the aperture17of the second connector member18(i.e., in the embodiment ofFIGS.11and12). Application of a tensile force in the length dimension of the fuse member414via the first and second connector members16,18may result in elongation or yielding of the fuse member414. The yielding may include straightening of the folds or bends of the corrugation430and the fuse member412. The yielding may include flattening or straightening of some of the corrugations and/or flattening or straightening of all of the corrugations.

The corrugated portion430may be formed as a separate piece that is connected to opposing end portions of the fuse member412using a separate connection step. Alternatively, the corrugated portion430is formed as a single-piece with remaining portions of the fuse member412.

In other embodiments, the corrugated portion430may have a different profile than the generally rectangular-shaped outer profile shown inFIGS.10and12. For example, the corrugated portion430can have a necked down or dog bone-shaped profile as described above with reference to fuse member12,112,312. The corrugation may have a variety of different shapes and sizes to provide different amounts of yielding for different applied tensile forces. The corrugated portion430shown inFIGS.10and12includes a generally wavy shape along its length.

FIGS.13and14illustrate another example seismic bracing yield fuse500wherein one or more fuse members512are positioned exterior the housing assembly514. The fuse member512may include first and second fuse members512a,512bthat each include first and second ends520,522and first and second retaining members532,533positioned at the opposing ends520,522. The fuse members512a,512bmay have a generally elongate construction. In some embodiments, the fuse members512a,512bhave a circular cross-sectional shape and may be referred to as rods. Other cross-sectional shapes are possible. Further, the generally constant cross-sectional shape and diameter and/or maximum width of the fuse members512a,512bshown inFIGS.13and14may be changed to be variable in other embodiments. In at least one example, one or more of the fuse members512a,512bmay include a reduced diameter/maximum width portion along its length to promote yielding at a certain location along the length and/or yielding at a specific tensile force or load application.

The housing assembling514includes first and second housing members534,536having first and second housing apertures538,540with closed ends542,544, respectively, and open ends546,548, respectively. The first housing member534includes a pair of mounting tabs554, and the second housing member536includes a pair of mounting tabs556. The mounting tabs554,556include mounting apertures558,560, respectively. Mounting tabs554,556may be used to secure the fuse members512a,512bto the housing assembly514. The retaining members532,533of the fuse members may be used to retain the fuse members512a,512bto the housing assembly514by preventing removal of the fuse members from the mounting apertures558,560.

In some embodiments, the first second housing members534,536are sized so that one is insertable into the other and they are arranged in a sliding interface with each other to permit a change in length L2between the housing apertures538,540. In other embodiments, the first second housing members534,536are abutted end-to-end and include an additional housing insert562(seeFIG.14) having insert apertures564,566that provide an interconnection between the housing members534,536with the apertures564,566aligned with the housing apertures538,540. The insert apertures564,566may have an elongate shape (e.g., similar to the elongate shape of the apertures338,340described above with reference toFIGS.7and8) that permit some elongation of the housing assembly514during yielding of the fuse members512a,512bupon application of the tensile force along the length of the yield fuse500. That is, as the length L1of the fuse members512a,512bincreases, the length L2between the housing apertures538,540is able to increase even with the insert562and associated apertures564,566connected to the housing members534,536. In other embodiments, the housing apertures538,540may have an elongate, slot-shaped construction and the apertures564,566may have either a circular construction or also include an elongate, slot-shaped construction (e.g., the shape shown inFIG.14) to permit the change in length L2as needed.

The application of a tensile force may be applied using the first connector16shown inFIGS.13and14and a second connector518. The connector518may have any of a variety of shapes and sizes, such as the angled bracket shape shown with reference toFIGS.1and2, or the generally flat shape shown inFIGS.13and14. The second connector518may include an aperture17to receive the fastener19to connect the second connector518to the housing assembly514. The second connector518may also include a second aperture521used to secure the seismic bracing yield fuse500to another structure such as the seismic ceiling mount82or a non-structural ceiling connectors88shown with reference toFIGS.15and16.

The embodiment ofFIGS.13and14may utilize portions of a housing assembly514to transfer the tensile forces to the fuse members512a,512b. Furthermore, the housing assembly shown inFIGS.13and14are not used as protective structure to enclose the fuse members512a,512b, such as to protect the fuse members from environmental conditions and associated damage. The embodiments disclosed with reference toFIGS.1-12provide a housing assembly that is intended to function primarily as a protecting structure for the fuse member. The housing member shown with reference toFIGS.1-12may be configured in a way such that they do not transfer the tensile forces to the fuse member, but instead are intended specifically not to transfer tensile forces to the fuse members. The fuse members described with reference toFIGS.1-12may in some embodiments be used as a seismic bracing yield fuse independent of the housing assembly. That is, the housing assembly shown in the embodiments ofFIGS.1-12may be removed without influencing the ability of the seismic bracing yield fuse to provide its intended function of providing a yield fuse in a seismic bracing application for a non-structural item of a building. The housing assemblies described with reference toFIGS.1-12may also be referred to as a protecting device, an enclosure for the fuse member, or the like to better indicate its function to protect the fuse member from environmental conditions such as, for example, during assembly of the seismic bracing yield fuse with a bracing or connecting assembly for the non-structural item, or during use to protect the fuse member from water, other corrosive environmental conditions, or impact by other items such as during installation of other piping, ducting, wiring or the like in the immediate vicinity of the non-structural item being supported by the seismic bracing.

The fuse members disclosed herein may comprise a variety of different materials, and particularly metal materials. Some example materials for use as the fuse member include, for example, mild steel (A36 or similar). However, aluminum or copper may also be used. Other non-ferrous materials may be used in combination with or in place of metal materials for the fuse members. Insulating washers could be incorporated into the fuse to inhibit corrosion if materials other the steel are used. Alternatively, commercially available insulating washers could be provided with the fuses if insulating washers were not incorporated into the fuses. The type of materials used for the housing assemblies disclosed herein may be of less importance with exception to the embodiment shown inFIGS.13and14where the housing assembly is intended to transfer the tensile forces to the fuse members and thus provide a more structural, force transferring function. In some embodiments, the housing assembly may provide a sealed enclosure for the fuse member.

The first and second connector members disclosed herein may comprise one or more of a variety of different materials. For example, the first connector member16may comprise a metal wire. The metal wire may be encased or coated with a non-corrosive material such as plastic, silicone or the like. The second connector member18may be comprised of a similar material to that used in the fuse yielding element, or may be a dissimilar material, as described herein.

Typically, the seismic bracing yield fuse as disclosed herein have a relatively small size. For example, the lengths L1, L2are typically in the range of about 1.5 inches to about 6 inches, and more particularly about 1.5 inch to about 3 inches. The length is determined by the length of material needed to develop desired ductile yielding effects while also being of sufficient strength to resist typical seismic bracing forces. The width W1, W2typically is in the range of about 0.75 inches to about 2 inches. The total weight of the seismic bracing yield fuse (i.e., the fuse member and housing assembly without the first and second connector members) typically is in the range of about 4 ounces to about 20 ounces, depending upon the fuse capacity.

The seismic bracing yield fuses as disclosed herein are specifically designed for use as part of seismic bracing for non-structural items in a building structure, as described above in detail. The size, strength, characteristics, and yield strength of the fuse members for the seismic bracing yield fuse as disclosed herein are on a scale that is much different from fuses used for structural building components such as the beams, brackets and bracing used to define the walls, ceiling, floors, etc. of the building structure itself. Thus, the problem being solved in association with seismic bracing is on a completely different scale. A person of ordinary skill in the art of seismic bracing would have no need to look to fuse members for structural building components because of the vastly different problems being solved, the scale of the features involved, and the like.

Unless otherwise noted, the terms “a” or “an,” as used in the specification and claims, are to be construed as meaning “at least one of.” In addition, for ease of use, the words “including” and “having,” as used in the specification and claims, are interchangeable with and have the same meaning as the word “comprising.” In addition, the term “based on” as used in the specification and the claims is to be construed as meaning “based at least upon.”