BLAST ABSORBING CLADDING
A blast resistant cladding includes a curtainwall arranged on a structure and defines a load path for transferring loads imparted on the curtainwall to the structure and an absorbing system positioned along the load path and configured for absorbing blast-type loads imparted on the curtainwall.
This application claims the benefit under 35 USC §119(e) to U.S. Patent Application No. 61/505,610 filed Jul. 8, 2011 entitled “Blast Absorbing Cladding” which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTIONThe present disclosure relates to mitigating blast loads imparted on building cladding. More particularly, the present disclosure relates to an absorbing system for mitigating blast loads on cladding thereby reducing the effect of the loads on the cladding as well as the building structure. Still more particularly, the present disclosure relates to an absorbing system incorporated into a curtainwall anchor for mitigating blast loads.
BACKGROUNDIn the wake of several terrorist attacks within the U.S. there has been a heightened level of protection provided by Federal, State, and Local law enforcement agencies. These efforts have included increased security measures and increased numbers of security personnel, particularly at highly attended and/or particularly vulnerable events. These efforts have also included putting additional thought into and conducting studies on how to minimize vulnerabilities when constructing new facilities and structures. Some of this additional thought and study relates to restricting access and providing more control over logistics of public and private entrances and exits to and from facilities. In some instances, where restricted access, separation, or other known techniques are not available or desirable, reinforcement of the vulnerable portion of the facility may be another solution.
In a building structure, the building façade is often the first line of defense against an attack on a structure. Where explosives, projectiles, or other dangerous systems are used near or directed toward a building, the building façade is likely the first portion of the building that will be contacted. The building façade, often formed of a curtainwall type structure, can be reinforced in an effort to better resist, for example, blast forces. However, the strength required to resist such forces is often balanced with the increased costs associated with it. In some cases, the increased costs may be justifiable and affordable, but in other cases, safety may be compromised due to costs, an aesthetic desire of the facility owner, or other limitations on reinforcement of the curtainwall system.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of invention is to be bound.
SUMMARYIn one embodiment, a blast resistant cladding may include a curtainwall arranged on a structure defining a load path for transferring loads imparted on the curtainwall to the structure. The cladding may include an absorbing system positioned along the load path configured for absorbing blast-type loads imparted on the curtainwall.
In another embodiment, a system for supporting exterior cladding and resisting blast forces imparted thereon may include a cladding interface for fixedly engaging the cladding, a structure interface for fixedly engaging the structure, and an engagement system positioned between the cladding interface and structure interface. The engagement interface may include a hanger system for vertically supporting the cladding and a bracing system for laterally supporting the cladding. The bracing system may include an absorbing system for absorbing the blast forces.
In still another embodiment, a blast resistant cladding may include a curtainwall arranged on a structure defining a load path for transferring blast-type loads imparted on the curtainwall to the structure and a means for absorbing blast-type loads imparted on the curtainwall.
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 to limit the scope of the claimed subject matter. Other features, details, utilities, and advantages of the present invention will be apparent from the following more particular written description of various embodiments of the invention as further illustrated in the accompanying drawings and defined in the appended claims.
The present disclosure relates to an absorbing system for mitigating blast loads imparted on the cladding of a building. The absorbing system may be positioned at any point along the blast load path and may be configured to transfer some of the blast load and absorb the remaining portion of the blast load. Accordingly, when passing through the absorbing system, the blast load may be at least partially absorbed thereby reducing the effect of the load on the components of the cladding and the building structure.
The absorbing system may include one or a combination of several devices configured for absorbing and transferring loads. In some embodiments, the absorbing system may include damping pads positioned along the blast load path and oriented substantially orthogonally to the path. The damping pads may be configured to absorb the load much like a combined spring and shock absorber or imperfect spring. In other embodiments, the absorbing system may include damping pads oriented substantially parallel to the load path. The damping pads, in this embodiment, may be configured to absorb the load similar to the system above, but by way of shear deformation rather than compressive or tensile deformation. In still other embodiments, the absorbing system may include elements adapted for inelastic deformation, sliding friction, or other energy absorbing mechanisms or devices. Advantageously, the dampening approaches described herein may improve the performance of the system not only under initial load but also by diminishing or reducing damage caused during rebound of the system.
With reference to
Other cladding systems may also be provided. For example other curtainwall systems such as that described in U.S. patent application Ser. No. 11/532,360 filed on Sep. 15, 2006 and entitled Curtainwall System, the contents of which are hereby incorporated by reference herein in their entirety, may be provided. In addition, the curtainwall described in U.S. Patent Application No. 60/867,341 filed on Nov. 27, 2006 and entitled Dual Wall System, the contents of which are hereby incorporated by reference herein in their entirety, may also be provided. Other curtainwall types may also be provided. Still other cladding systems may include, for example, stone on truss type cladding, cladding applied to studs, precast panels, window walls, and other cladding systems suspended from a structure. More particularly, the systems described herein may be applied to pre-cast panels, stick wall systems and to studs on sheathing supporting rain screen systems such as panels, stone and terra cotta.
With reference again to
Aside from the absorbing system being provided and described herein, a curtainwall system 100 may have some ability to absorb load. As shown in
With the context provided above, several embodiments of an absorbing system may be described. It is noted that the embodiments disclosed herein include an absorbing system associated with the connection of the mullions 104 of the curtainwall 100 to the building structure. This particular location for the absorbing system can be advantageous because it reflects a logical break in the load path relating to the assembly and installation of the cladding. However, as mentioned, it is within the scope of the present disclosure to position the absorbing system anywhere along the load path.
The embodiments disclosed herein include a securing device for securing exterior cladding to a building. The securing device can be an anchor system 105 configured to support a curtainwall 100 relative to a building structure. The anchor system 105 can include several elements adapted to suspend the curtainwall 100 from the building and allow for adjustment during installation. Moreover, the anchor system 105 may include a bracing system for bracing the curtainwall laterally relative to the supporting structure thereby accommodating wind loads, internal building pressures differentials, blast loads or other lateral acting loads imparted on a curtainwall system. The absorbing system may be incorporated into the bracing system allowing the anchor to more effectively absorb blast forces imparted on the exterior or interior of the curtainwall 100. Accordingly, the absorbing system may reduce the effect of forces imparted on the curtainwall 100 thereby allowing for a more economical and safe solution. That is, the absorbing system may allow the curtainwall 100 and the building structure to be more resistant to imparted loading without needing to be unduly reinforced.
With reference to
With continued reference to
The fist 152 may include a securing portion 166 and an adjustment portion 168. The securing portion 166 may be adapted for positioning adjacent to and securing to the mullion 104. Where the mullion 104 is a rectangular element, with relatively flat sides, the securing portion 166 may also be flat in the form of a plate and may be positioned on or coupled to the surface of the mullion 104. The securing portion 166 may be constructed of steel, aluminum, other metals, an alloy, or a composite material. Other materials may also be used. In the case of a steel securing portion 166 in the form of a plate, the plate may have a thickness ranging from approximately ⅛″ to approximately ¾″. In other embodiments, the plate may have a thickness ranging from approximately 3/16″ to approximately ⅝″. In still other embodiments, the plate may be approximately ¼″ thick. Thicker or thinner plate thicknesses may also be provided. The securing portion 166 of the fist 152 may be fastened to the mullion 104 with a plurality of fasteners 167 such as screws, bolts, self-tapping screws, self-drilling screws, or other fasteners. In other embodiments, the securing portion 166 may be welded or otherwise secured to the mullion 104 or may be an integral portion of the mullion 104. For example, the securing portion 166 may be extruded together with the mullion 104.
As mentioned, in addition to the securing portion 166, the fist 152 may include an adjustment portion 168 and the adjustment portion 168 permits adjustment of the mullion 104 relative to the support structure or building 102 in one of a lateral and horizontal direction or both. In the embodiment shown, the adjustment portion 168 is configured for vertical adjustment. The adjustment portion 168, as seen in FIGS. 5B and 5B-1, may include a hollow shaft structure 170 formed by a shaft wall 172 extending along the vertical length of the securing portion 166. The shaft structure 170 may be configured to allow an adjustment element 203 to translate vertically along the length of the shaft 170. As shown, the shaft wall 172 may be generally cylindrical and may extend fully along the length of the securing portion 166. In other embodiments, the shaft wall 172 may extend partially along the securing portion 166 or beyond the securing portion 166. The shaft wall 172 may have a longitudinal adjustment control 173 in the form of a helical thread 173 on an inner surface providing for screw-like propagation of an adjustment screw, for example, that, in turn, adjusts the position of the adjustment element 203 along the length of the shaft 170. Other longitudinal adjustment controls 173 can also be used such as, for example, ratchet features and pin and socket features. The shaft 170 may also include an elongate opening 174 extending fully or partially along its length allowing elements to extend through the shaft wall 172 into the shaft 170 and, for example, connect to the adjustment element positioned in the shaft 170. The elongate opening 174 may have a width at least slightly smaller than the corresponding shaft dimension to prevent escape of the adjustment element 203 laterally through the shaft wall 172. For example, where the shaft 170 has a circular cross-section, the width of the elongate opening 174 may be at least slightly smaller than the diameter of the shaft 170. The adjustment portion 168 may be made from the same material as the securing portion 166 and they may be extruded or molded as a single piece after which the helical threads may be cut into the shaft 170.
As mentioned, the anchor system 150 may include a structure interface 154 in addition to the curtainwall interface or fist 152. The structure interface 154 may be coupled to or configured for connection to the surface of a concrete slab 106 near an edge, for example. In other embodiments, the structure interface 154 may be positioned in or coupled to an embed and secured to the embed. For example, the structure interface 154 may be provided as shown and described in any or all of U.S. patent application Ser. No. 11/208,444 filed on Aug. 19, 2005, Ser. No. 12/422,754 filed on Apr. 13, 2009, and Ser. No. 12/422,799 filed on Apr. 13, 2009, each entitled Adjustable Attachment System. The contents of each of these applications are hereby incorporated by reference herein in their entireties. In still other embodiments, the structure interface 154 itself may be in the form of an embed. In any or all of the above cases, the structure interface 154 may be configured to be secured directly or indirectly to a base element in the form of a floor system 106 of a building 102 thereby transferring vertical and lateral acting loads imparted on the curtainwall 100 to the building 102. As such, the structure interface 154 may be a bracket, plate, pin, rod, hole, or other feature allowing floor system 106 or other portion of the building 102 to be engaged with the structure interface. Similar to the curtainwall interface or fist 152, the structure interface 154 may be separate from or integral with the floor system 106 or other portion of the building 102. In some embodiments, the structure interface or bracket 154 may be made of steel, stainless steel, or other appropriate material.
In the embodiment shown in
As shown, a top surface 153 of the bracket 154 may include a gripping feature or surface 180A such as, for example, a roughened or toothed surface. A washer 182 may also be coupled to the bolt or anchoring element 178 and a bottom surface 181 of the washer 182 may also include a gripping feature or surface 180B such as, for example, a roughed or toothed surface for engaging the roughened or toothed surface of the bracket 154. A nut or other fastening element 184 couples or causes engagement of the opposing gripping features 180A/B of the washer 182 and bracket 154 thereby fixing the position of the bracket 154 relative to the bolt or anchoring element 178, and thus fixing the bracket 154 position relative to the edge of the base 106. Multiple slotted holes 176 and anchor bolts 178 may be provided to prevent twisting of the bracket 154 about the bolt or anchoring element 178 or to provide more strength. As shown, where more than one slotted holes 176 are provided, the slotted holes 176 may be arranged generally parallel to one another to facilitate an adjustable position of the bracket 154 by sliding the bracket 154 relative to the anchor bolts 178 prior to installing the washer 182 and nut 184.
In addition to the flat surface or portion 155, the bracket 154 may include an upturned leg 186 arranged generally perpendicular to the flat surface 155 and extending laterally from the edge of the bracket 154. The upturned leg 186 may include an inboard surface 188 facing the building or structure 102 and an outboard surface 190 facing away from the building or structure 102. The upturned leg 186 may also include a cap bearing element 192 positioned on the top edge of the leg 186 and extending along the length of the leg 186. In cross-section, the cap bearing element 192 may have a relatively flat top surface and may have arcuate upper corners transitioning into relatively vertical sides and a relatively flat bottom surface. In other embodiments, the cap bearing element 192 may have a circular or other cross-section. The cap bearing element 192 may have a width or circumference slightly larger than the width or thickness of the upturned leg 186 of the bracket 154 and it may be centered on the upturned leg 186 causing the cap bearing element 192 to overhang the upturned leg 186 on each of the outboard and inboard faces 188, 190 creating leg cavities 194. The bracket 154 may have a width, measured along the edge of the floor 106, larger than a width of a mullion 104 allowing the fists 152 secured to the sides of the mullion 104 to be connected to the bracket 154 with an engagement system 156.
As mentioned, and as indicated in
Turning first to the hanger system 158, it may include a device, a portion of a device, or system of devices adapted for engaging the fist 152 and the floor bracket 154 and hanging the curtainwall 100. As such, it may include a hook, lip, ledge, tab, pin, rod, or portion thereof configured to connect the fist 152 to the floor bracket 154. With reference to
As indicated in
In some embodiments, the floor bracket engaging portion 198 may be a tab, lip, rod, or other element which extends from the main body 200, bears on or otherwise engages the floor bracket 154, and prevent relative vertical displacement between the fist engaging portion 196 of the hanger system 158 and the floor bracket 154. One embodiment of the floor bracket engaging portion 198 shown in
The boom portion 198 may be fixedly secured to the main body 200 to prevent displacement and rotation therebetween. For example, the boom 198, like the main body 200, may be a plate-like element and may be formed together with the main body portion 200 from a single piece of material. The boom 198 may extend substantially horizontally from the main body 200 and may bear on top of the upturned leg 186 of the floor bracket 154. More particularly, the boom 198 may bear on the top surface of the cap bearing element 192 positioned on the top of the upturned leg 186.
As described, the hanger system 158 may provide vertical support to the curtainwall 100 by way of the adjustment element 203 engaging the shaft 170. The adjustment element 203 may be rigidly connected or coupled to the tab element 202, which may be rigidly connected or coupled to the main body 200, which may be rigidly connected or coupled to the boom 198 and the boom 198 may bear on the floor bracket 154. It is noted that the offset nature of the support of the curtainwall 100 at the fist 152 relative to the bearing point on the floor bracket 154 may induce a moment in the hanger system 158. In other embodiments, the support of the curtainwall 100 at the fist 152 relative to the bearing point on the floor bracket 154 may be in-line rather than off set. The main body 200 together with the tab element 202 and adjustment element 203 positioned in the shaft 170 may have a height H, measured along the fist 152, adapted to resist the induced moment. In one embodiment, the main body 200 may have a height between approximately ½ inch and approximately 4 inches. In another embodiment, the main body 200 may have a height up to and including approximately 2 feet. In another embodiment, the main body 200 may have a height between approximately 1 inch and approximately 3 inches. In still other embodiments, the main body 200 may have a height of approximately ½ inches. In still other embodiments, the main body 200 may be longer than approximately 4 inches or shorter than approximately ½ inch and may have a length similar to the spandrel height of the associated curtainwall, for example. Suitable heights may be selected to resist the imparted loads and also accommodate desires to keep the portions of the anchor secluded and out of sight. Other heights may also be provided.
As mentioned, the engagement system 156 for connecting or engaging the curtainwall interface or fist 152 and the structure interface or floor bracket 154 may include a bracing system 160 in addition to the hanger system 158 just described. The bracing system 160 may be separate from or partially integral with the hanger system 158. In the embodiment shown in
Accordingly, as mentioned, the engagement system 156 may include a hanger system 158 and a bracing system 160, each of which may be separate parts or may be formed by a portion of a single part. In the embodiment described, the hanger system 158 and bracing system 160 are partially integral in that they each include portions of the hook which connects the fist 152 to the floor bracket 154. In some embodiments, as mentioned, the engagement system 156 may be further integral with the structure interface 154 by being fixedly or slidingly secured or otherwise coupled thereto.
As can be understood from
The damping device 212 may be configured for absorbing and damping loads passing through the bracing system 160. In some embodiments, the damping device 212 may include a energy storing and releasing device such as a spring, for example, and a shock absorber using fluids such as a dash pot device, for example. In some embodiments, the energy storing/releasing function and dash pot or damping function may be provided by a single device. In the present embodiment, as shown in
While the distribution element 208 has been described as being arranged on the hook and not on the floor bracket 154, the upturned leg 186 of the floor bracket 154 may form an opposing distribution element for positioning of the damping device 212 therebetween. In other embodiments, distribution element 208 may be arranged on the floor bracket 154 and a natural surface of the hook may oppose the distribution for placement of a damping device 212 therebetween. In other embodiments, the absorbing system 162, or elements of the absorbing system 162, are placed in other locations along the load path. For example, in one embodiment shown in
The damping pads may have a neutral (i.e., unstressed) thickness substantially equal to the space between the distribution elements 208 and the faces 188, 190 of the upturned leg 186. In some embodiments, the thickness of the damping pads may be between approximately 1/16 inch and approximately 1 inch. In other embodiments, the thickness may be between approximately ⅛ inch and approximately ½ inch. In still other embodiments, the thickness may be approximately 3/16 inch. Multiple layers of damping material may be provided and adhesives may be provided between the layers. The layers of damping material may all be the same material or several types of material may be provided in the several layers. The thickness of the damping pads may be selected to accommodate the space available within the wall in addition to other load considerations. That is, for wind loads, for example, limitations for allowable deflections must be met, so highly flexible and low resistant materials may not satisfy these requirements.
The distribution elements 208 in conjunction with the damping device 212 may allow the absorbing system 162 to distribute lateral acting loads to a relatively larger area of the upturned leg 186 of the floor bracket 154. The distribution of the force over a larger area may reduce the force per unit area that is being transferred and dissipated thereby increasing the efficacy of the system. In some embodiments, the surface area of the planar surface for each distribution element 208 and the size of the damping pads may be between approximately ¼ square inches and 9 square inches. In other embodiments, the area may be between approximately ½ square inches and 4 square inches. In still other embodiments, the area may be approximately 1 ½ square inches. Larger or smaller areas may also be provided.
It is noted that under lateral acting loads, the horizontally offset nature of the position of the bracing system 160 and corresponding absorbing system 162 relative to the longitudinal axis of the shaft 170 of the fist 152 may induce horizontal rotation of the bracing system 160 about the longitudinal axis of the fist shaft 170. As shown in
With reference to
Accordingly, the bracing system 260 shown may be partially integral with the hanger system 258 like the bracing system 160 of
The bracing system 260 shown may include a U-shaped hook 314 having an inboard vertical leg 316 and an outboard vertical leg 318 connected to one another by a distribution body 320. It is noted that the boom 298 of the present embodiment may include a planar surface 307 arranged generally parallel to a lateral acting force direction. Other orientations of the planar surface 307 may be provided including oblique orientations. It is noted that while the planar surface 307 shown is oriented substantially vertically, the planar surface 307 can be horizontal or at some angle between vertical and horizontal. The distribution body 320 of the hook 314 may be positioned adjacent the boom 298 of the hanger system 258 and may include a planar surface 309 positioned in a plane adjacent to and parallel to the planar surface 307 of the boom 298. The damping or planar surface 309 of the distribution body 320 may be separated from the planar surface 307 of the boom 298 defining a space therebetween. In this embodiment, the distribution body 320 and the boom 298 may function as distribution elements 308. The vertical legs 316, 318 of the hook portion 314 may fixedly extend from the distribution body 320. That is, the vertical legs 316, 318 may be secured to the distribution body 320 to prevent relative displacement and relative rotation therebetween, for example, by being part of the same plate. Each vertical leg 316, 318 may be positioned adjacent a respective inboard or outboard face 288, 290 of the upturned leg 286 of the floor bracket 254 and, as such, may be spaced from one another a distance substantially equal to the width of the bearing cap element 292. Where a bearing cap element 292 is not provided, the spacing of the vertical legs 316, 318 may be substantially equal to the thickness of the upturned leg 286 of the floor bracket 264. Clearances for installation of the hook 314 may be provided to avoid an overly tight fit of the hook 314 over the upturned leg 286 of the floor bracket 254. That is, the hook 314 is receivingly engaged with the bearing cap element 292 or the upturned leg 286 to allow for some movement (vertical, lateral) between these elements of the system as needed. As previously described, all or a portion of the engagement system 256 may be secured to the floor bracket 254 or it may be separate therefrom.
As with the previous embodiment described with regard to
The damping pads 312 and the corresponding planar surfaces 307, 309 may be configured to distribute the lateral acting loads over a relatively large area. Accordingly, the planar surfaces 307, 309 and damping pads 312 may have a surface area between approximately ¼ square inches and 9 square inches. In other embodiments, the area may be between approximately ½ square inches and 4 square inches. In still other embodiments, the area of the planar surface 307, 309 may be approximately 1 ½ square inches. The pad or plurality of pads may have a thickness measured between the planar surfaces 307, 309 between approximately 1/16 inch and approximately 1 inch. In other embodiments, the thickness may be between approximately ⅛ inch and approximately ½ inch. In still other embodiments, the thickness may be approximately 3/16 inch. Other sizes and thicknesses may also be used and may be selected to suitably damp loads imparted on the system.
Multiple layers of damping material may be provided and adhesives may be provided between the layers. The layers of damping material may all be the same material or several types of material may be provided in the several layers. Where multiple layers are used, the several damping pads may be adhered to one another with epoxy, polyurethane, or polyisocyanate adhesive. Other adhesives may also be used.
As with the embodiment of
In some embodiments, as may be shown best in
In the embodiment shown in
With further reference to
It is also noted that a combination of shear and normal type systems may be provided. For example, the bearing type system described with respect to
With reference to
As best shown in
The bracing system 360 shown, may be partially integral with the hanger system 358 like the bracing system 160 of
As shown, in
The absorbing system 362 of the bracing system 360 of this embodiment may be provided by material ductility. That is, the hanger system 358 and bracing system 360 may be constructed of a ductile material such as steel, steel alloy, or other substantially ductile material. Other ductile materials may also be used. In this embodiment, the damping device 412 of the absorbing system may be in the form of a ductility feature which may help to make the main body 400 and hook leg 406 prone to ductile failure. The ductility features may be any notch, perforation, break line, or other shaped feature that may lessen the cross-sectional area available to resist the lateral acting loads. As shown best in
With particular reference to
With reference again to
With reference to
Other ductility features may include a plurality of circular perforations arranged in a grid or arranged in a staggered or nested grid. In still other embodiments, combinations of slots and circular perforations may be provided. In still other embodiments, triangular, rectangular, square, diamond, or other shaped perforations may be provided. In other embodiments, the ductility features may be positioned to allow the main body 400 or vertical hook leg 406 to bend relative to the boom 398.
While the absorbing system of the present disclosure has been described in detail with respect to at least three anchor embodiments, modifications or changes may be made and remain within the scope of the invention. For example, the location of the absorbing system may be modified. That is, for example, in the embodiment shown, the damping pads are positioned between the structure interface and the curtainwall interface. That is, when considering the path of the load from the curtainwall 100 to the structure 102, the load passes through the curtainwall interface, then the damping pads, and then into the structure interface. In other embodiments, the damping pads may be located, for example between the curtainwall interface and the curtainwall. For example shear force-type and/or normal force-type bracing systems may include placing damping pads between the fist and the mullion. In other embodiments, the damping pads may be located, for example between the structure interface and the structure. For example, shear force-type and/or normal force-type bracing systems may include damping pads between the floor bracket and the floor or associated embed. In still other embodiments, the damping pads or ductility type devices may be positioned between the mullion and the structure apart from the anchor system. In this embodiment, the anchor system may be provided with some lateral play or freedom to move thereby isolating the anchor system from the lateral acting load path and allowing lateral acting forces to resisted by the absorbing system located along a load path not traveling through the anchor system. In still other embodiments, the absorbing system may be positioned at any location along the load path.
As another example of a modification within the scope of the invention, the curtainwall interface and the structure interface may be one in the same. That is, the curtainwall interface and structure interface may be one integral component, such as a steel angle or other bracket, that engages both the curtainwall and the structure. In these embodiments, the damping element may be provided internally, similar to
As another example of a modification within the scope of the invention, combinations of the embodiments shown may be provided. In one embodiment, combinations of normal force-type and shear force-type systems can be used. For example, the ductility features of the embodiment shown in
As another example of a modification within the scope of the invention, additional damping resistance or features may be added through duplication or otherwise. For example, in the embodiment shown in
As another example of a modification within the scope of the invention, the damping device may be constructed of alternative materials. For example, in one embodiment, the damping device is made of a “crushable” material such as sand, stone, plaster board. cement board or other appropriate material that could absorb a blast. A device made of such crushable material may be constructed as a replaceable insert for the system.
The embodiments disclosed, or variations or modifications thereof can be advantageous for several reasons. Particularly, damping, in lieu of, or in addition to strengthening, reduces the affect of the forces on the curtainwall and the building. As such, costs associated with reinforcing the curtainwall can be reduced while the safety of the structure can be maintained. To better explain this advantage, two exemplary models may be described.
Referring to
Span=12′6″
Unit Width=5′0″
Impulse Pressure=6.5 psi
Impulse Duration=14 milliseconds
Allowable Ductility Factor=3
Allowable Rotation=3°
Section Profile=Rectangular H10″×W3″×T1/4″
Material=Aluminum 6061-T6 fy=35 ksi, fu=58 ksi
Wind Load=50 psf dmax=span/175
Based on these assumptions remaining constant between each of the curtainwall systems and only the support stiffnesses differing, the two systems were compared. As shown in
Similarly as shown in
Referring to
Span=12′6″
Unit Width=5′0″
Impulse Pressure=6.5 psi
Impulse Duration=14 milliseconds
Allowable Ductility Factor=3
Allowable Rotation=3°
Section Profile=Rectangular H10″×W3″×T1/4″
Rectangular H7″×W3″×T1/4″
Material=Aluminum 6061-T6 fy=35 ksi, fu=58 ksi
Wind Load=50 psf dmax=span/175
Support Stiffness=10 kips/inch for flexible support.
As shown in
One having ordinary skill in the art should appreciate that there are numerous types, shapes, and sizes of cladding for which there can be a need or desire to damp blast loads according to an exemplary embodiment of the present invention. Additionally, one having ordinary skill in the art will appreciate that although the preferred embodiments illustrated herein reflect a generally flat and rectangular damping pad and generally slotted ductility features, these elements can have a variety of shapes and sizes.
All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, outboard, inboard, outer, inner, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary.
In addition, the term “about” or “approximately” should generally be understood to refer to both the corresponding number and a range of numbers. In addition, all numerical ranges herein should be understood to include each whole integer or fraction thereof within the range. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention as claimed below. Although various embodiments of the invention as claimed have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention. Other embodiments are therefore contemplated. It is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative only of particular embodiments and not limiting. Changes in detail or structure may be made without departing from the basic elements of the invention as defined in the following claims.
Claims
1. A blast resistant cladding, comprising:
- a curtainwall coupled to a structure by an anchor system and defining a load path for transferring loads imparted on the curtainwall to the structure; and
- an absorbing system positioned along the load path to absorb blast-type loads imparted on the curtainwall.
2. The cladding of claim 1 wherein the absorbing system comprises a normal force-type device to absorb and damp the forces through compression and tension.
3. The cladding of claim 2, wherein the absorbing system comprises a damping pad positioned between a pair of distribution elements, the distribution elements including damping surfaces and each surface of the distribution element coupled to a corresponding surface of the anchor system.
4. The cladding of claim 3, wherein the damping surfaces of the distribution elements are planar and the corresponding surface of the anchor system is planar.
5. The cladding of claim 1, wherein the absorbing system comprises a shear force-type device to absorb and damp the forces through shear deformation.
6. The cladding of claim 5, wherein the absorbing system comprises a damping pad positioned between a pair of distribution elements, the distribution elements including damping surfaces and each damping surface of the distribution element coupled to a corresponding surface of the anchor system.
7. The cladding of claim 6, wherein the damping surfaces of the distribution elements are planar and the corresponding surface of the anchor system is planar.
8. The cladding of claim 6, wherein the damping pad includes a plurality of damping layers, each layer separated by warp resisting elements.
9. The cladding of claim 1, wherein the absorbing system comprises a ductility feature to dissipate forces through ductile deformation.
10. The cladding of claim 9, wherein the ductility feature comprises a perforation positioned near an edge of the absorbing system to allow the edge to fail in a ductile manner under loading.
11. A system for supporting exterior cladding on a structure and resisting blast forces imparted thereon, the system comprising:
- a cladding interface for fixedly engaging the cladding;
- a structure interface for fixedly engaging the structure; and
- an engagement system positioned between the cladding interface and structure interface, comprising:
- a hanger system for vertically supporting the cladding; and
- a bracing system for laterally supporting the cladding, the bracing system having an absorbing system for absorbing the blast forces.
12. The system of claim 11, wherein the absorbing system comprises a damping pad positioned between two opposing distribution elements, the distribution elements including damping surfaces and each damping surface of the distribution element coupled to a corresponding surface of the bracing system.
13. The system of claim 12 wherein the surfaces of the distribution elements are planar and the surface of the bracing system is planar.
14. The system of claim 12, wherein each damping surface of the distribution element is in a plane generally adjacent to and parallel to a plane defined by a corresponding surface of the bracing system.
15. The system of claim 12, wherein the bracing system is a shear force-type system.
16. The system of claim 15, wherein the damping pad is oriented generally orthogonally to an exterior surface of the cladding.
17. The system of claim 16, wherein the damping pad comprises two damping layers positioned between the distribution elements with a warp resisting element positioned between the two damping layers.
18. The system of claim 16, wherein the damping pad comprises three damping layers with two warp resistant elements positioned therebetween.
19. The system of claim 11, wherein the bracing system is a normal force-type system.
20. The system of claim 19, wherein the damping pad is oriented generally parallel to an exterior surface of the cladding.
21. The system of claim 11, wherein the absorbing system is a ductile failure-type system.
22. The system of claim 21, wherein the absorbing system comprises a ductility feature.
23. The system of claim 22, wherein the ductility feature includes a plurality of slots separated by ductile partitions and the slots fail in a ductile manner.
24. The system of claim 23, wherein the plurality of slots are arranged in a chevron pattern, the chevron pattern comprising two legs.
25. The system of claim 24, wherein the ductility feature includes a circular perforation arranged in the gap between the legs of the chevron pattern.
26. The system of claim 23, wherein the plurality of slots are arranged adjacent to one another.
27. The system of claim 22, wherein the ductility feature includes at least one circular perforation.
28. A blast resistant cladding, comprising:
- a curtainwall arranged on a structure and defining a load path for transferring blast-type loads imparted on the curtainwall to the structure; and
- a means for absorbing blast-type loads imparted on the curtainwall.
Type: Application
Filed: Jul 9, 2012
Publication Date: Jan 17, 2013
Inventors: Tejav Dehghanyar (Marina Del Rey, CA), Michel Michno (Minneapolis, MN)
Application Number: 13/544,804
International Classification: F41H 5/24 (20060101); F41H 5/04 (20060101); F41H 5/013 (20060101); E04H 9/04 (20060101); E04B 2/90 (20060101);