Patent Publication Number: US-2010126797-A1

Title: Panel Assembly For Traffic Noise Barrier Wall

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. application Ser. No. 10/777,442, filed Jun. 17, 2008 (now U.S. Pat. No. 7,546,900, issued Jun. 16, 2009), which is incorporated by reference as if disclosed herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to traffic noise barrier walls. More specifically, this invention relates to panels for traffic noise barrier walls. 
     2. Description of the Related Art 
     Traffic noise barrier walls serve to shield otherwise quiet areas from noise caused by automotive, railway, aircraft, marine, or pedestrian traffic. A typical traffic noise barrier wall is from about 4 to 18 feet in height and runs continuously alongside a selected section of a roadway, railway, aircraft runway, waterway, parking lot, walkway, and the like. Such walls are typically constructed of acoustically absorptive or reflective panels supported by vertically mounted posts. 
       FIG. 1  depicts one common design of a traffic noise barrier wall, which is indicated at  10 . In the traffic noise barrier wall of  FIG. 1 , each panel  12  is constructed of wood or concrete and is supported between an adjacent pair of vertically mounted posts  14 , with the side edges  16  of the panel  12  being received within slots  18  disposed in the posts  14  in “drop-down” fashion. That is, the side edges  16  of each panel  12  are aligned with the slots  18  and the panel  12  is lowered between the posts  14  to secure the panel  12  between the posts  14 . Examples of such noise barrier walls are found in U.S. Pat. Nos. 5,713,170 and 5,537,788, both issued to Elmore et al. Noise barrier walls of this type are suitably sturdy and effective in reducing highway noise. However, the support posts must be sized to support the substantial weight of the wood or concrete panels under various environmental loads (e.g., wind loads, earthquake loads, etc.). As a result, the support posts found in such noise barrier walls are large and expensive to manufacture. Moreover, if it becomes necessary to increase the height of the wall after the wall has been built, the addition of more concrete or wood panels to the existing post structure is often times impossible due to the inability of the posts to handle the increased load caused by the additional panels. Such an addition in height may be required, for example, as noise regulations become more stringent or as the amount of noise generated by the traffic increases. Therefore, to increase the height of such noise barrier walls, the existing posts must be replaced at great expense. 
     Yet another drawback to the use of wood or concrete panels in a traffic noise barrier wall is that they block the view of any roadside businesses or scenery from travelers on the roadway. To overcome this deficiency, wall systems employing transparent panels have been developed. For example, U.S. Pat. No. 4,214,411 issued to Pickett describes panels of transparent polycarbonate resin for use as an acoustical barrier wall along a highway. While such wall systems are effective in providing travelers with a view outside the roadway, they typically require unique mounting structures that do not lend themselves to retrofit into the posts commonly used in traffic noise barrier walls. 
     BRIEF SUMMARY OF THE INVENTION 
     A traffic noise barrier wall is disclosed. In some embodiments, the traffic barrier wall includes the following: a first vertically-mounted post including a first slot disposed therein, the first slot extending lengthwise along a side of the first post; a second vertically-mounted post spaced apart from the first post, the second post including a second slot disposed therein, the second slot extending lengthwise along a side of the second post; and a first panel assembly extending between the first and second posts, the first panel assembly including a sheet of material having top, bottom, and side edges forming a perimeter of the sheet, and a frame disposed along at least a portion of the perimeter of the sheet including top, bottom, and side portions, wherein side portions of the frame capture at least a portion of the side edges of the sheet, the side portions of the frame being received within the first and second slots in drop-down fashion, wherein each of the side portions of the frame includes a base portion disposed outside one of the side edges of the sheet, said base portion having a substantially rectangular cross-section, first and second flanges disposed on the base portion, the first and second flanges forming at least a portion of a channel for capturing the side edge of the sheet, wherein at least the base portion is received in one of the first and second slots. 
     A panel assembly for a traffic noise barrier wall of the type including opposing slots formed in pairs of vertically-mounted posts is disclosed. In some embodiments, the panel assembly includes the following: a sheet of material having top, bottom, and side edges forming a perimeter of the sheet, said sheet having a sheet thickness that is less than each of said first slot width and said second slot width, and a frame disposed along at least a portion of the perimeter of the sheet including top, bottom, and side portions, wherein side portions of the frame include a base portion disposed along one of the side edges of the sheet, said base portion having substantially square outside portions that are connected to define a central channel and an overall substantially u-shaped cross-section, each of said outside portions including a connecting portion, wherein said central channel captures at least a portion of the side edges of the sheet. 
     A panel assembly system for a traffic noise barrier wall of the type including opposing slots formed in pairs of vertically-mounted posts and vertically stacked panel sheets is disclosed. In some embodiments, the panel assembly includes the following: at least two panels of material having top, bottom, and side edges forming a perimeter of each panel, each panel having a thickness that is less than each of said first slot width and said second slot width; and a frame disposed along at least a portion of the perimeter of the sheet including top, bottom, and side portions, wherein side portions of the frame include a base portion disposed along one of the side edges of the sheet and first and second flange portions projecting outward from the base portion on opposite sides of the sheet to define a channel between said first and second flange portions for capturing at least a portion of the side edges of the sheet, said frame having an overall thickness that is substantially equivalent to said base portion, said base portion having a substantially rectangular cross-section, wherein at least the base portion is received in one of the first and second slots, and a connecting bracket positioned between said first and second panels, said connecting bracket including male and female portions each having a substantially triangular cross-section, said male portion having a protruding portion and said female portion having a recessed portion that mates with said protruding portion, and each of said male and female portions including first and second flanges extending from a side opposite of said protruding and recessed portions, the first and second flanges forming at least a portion of a channel for capturing the top and bottom edges of the sheets. 
     A method of assembling a panel assembly for a traffic noise barrier wall of the type including opposing slots formed in pairs of vertically-mounted posts is disclosed. In some embodiments, the method includes the following: providing at least two panels of material having top, bottom, and side edges forming a perimeter of each panel; joining a frame including top, bottom, and side portions around said perimeter of each panel; temporarily connecting to said top portion of a first one of said at least two panels; placing said first one of said at least two panels between one of said pairs of vertically-mounted posts so that said side portions of said first one of said at least two panels are retained within said slots of said posts, wherein said top portion is released after said first one of said at least two panels is positioned between said posts; temporarily connecting to said top portion of a second one of said at least two panels; placing said second one of said at least two panels between said one of said pairs of vertically-mounted posts so that said side portions of said second one of said at least two panels are retained within said slots of said posts and said second one is positioned on top of said first one, wherein said top portion is released after said second one of said at least two panels is positioned between said posts; and removing said top portion of said second one of said at least two panels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings wherein like elements are numbered alike, and in which: 
         FIG. 1  is a perspective view of a prior art traffic noise barrier wall having panels received between posts in drop-down fashion; 
         FIG. 2  is a cross-sectional elevation view of a traffic noise barrier wall including panel assemblies of the present invention; 
         FIG. 3  is a cross-sectional plan view of a traffic noise barrier wall of  FIG. 2 ; 
         FIG. 4  is a detail view of a portion of the traffic noise barrier wall of  FIG. 2 ; 
         FIG. 5  is a cross-sectional elevation view of a portion of the traffic noise barrier wall of  FIG. 2 ; 
         FIG. 6  is a cross-sectional plan view of a portion of an alternative embodiment of the traffic noise barrier wall of  FIG. 2 ; 
         FIG. 7  is a cross-sectional elevation view of a portion of the alternative embodiment of the traffic noise barrier wall of  FIG. 2 ; 
         FIG. 8  is a cross-sectional elevation view of a traffic noise barrier wall including panel assemblies in accordance with another embodiment of the present invention; 
         FIG. 9  is a cross-sectional plan view of the traffic noise barrier wall of  FIG. 8 ; 
         FIG. 10  is a detail view of a portion of the traffic noise barrier wall of  FIG. 8 ; 
         FIG. 11  is a cross-sectional elevation view of a portion of the traffic noise barrier wall of  FIG. 8 ; 
         FIG. 12  is a cross-sectional elevation view of a traffic noise barrier wall including panel assemblies in accordance with yet another embodiment of the present invention; 
         FIG. 13  is a cross-sectional plan view of the traffic noise barrier wall of  FIG. 12 ; 
         FIG. 14  is a detail view of a portion of the traffic noise barrier wall of  FIG. 12 ; 
         FIG. 15  is a cross-sectional elevation view of a portion of the traffic noise barrier wall of  FIG. 12 ; and 
         FIG. 16  is a cross-sectional elevation view of a traffic noise barrier wall including panel assemblies according to some embodiments of the present invention; 
         FIG. 17  is a top plan view of a base portion according to some embodiments of the present invention; 
         FIG. 18  is a top plan view of a connecting bracket according to some embodiments of the present invention; 
         FIG. 19  is a top plan view of a base portion according to some embodiments of the present invention; 
         FIG. 20  is is a top plan view of a base portion according to some embodiments of the present invention; 
         FIG. 21  is a top plan view of a bottom portion of a connecting bracket according to some embodiments of the present invention; 
         FIG. 22  is a top plan view of a top portion of a connecting bracket according to some embodiments of the present invention; and 
         FIG. 23  is a cross-sectional elevation view of a traffic noise barrier wall including panel assemblies according to some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  depicts a cross-sectional elevation view of a traffic noise barrier wall  48  including panel assemblies  50  of the present invention.  FIG. 3  is a plan view of the traffic noise barrier wall  48 . The traffic noise barrier wall  48  is of the type that serves to shield otherwise quiet areas from noise caused by automotive, railway, aircraft, marine, or pedestrian traffic. The traffic noise barrier wall  48  may be positioned alongside a selected section of a roadway, railway, aircraft runway, waterway, parking lot, walkway, and the like, and has a height that is appropriate for the particular noise abatement requirements of the wall. For example, the height of the noise barrier wall may be from about 4 to 18 feet. 
     Referring to  FIGS. 2 and 3 , the noise barrier wall  48  includes spaced-apart, vertically mounted posts  14  having panel assemblies  50  extending between each pair of posts  14 . The panel assemblies  50  each include a sheet  54  of material having top  56 , bottom  58 , and side edges  60  forming a perimeter of the sheet  54 , and a frame  62  disposed around the perimeter of the sheet  54 . At least a portion of each of the top, bottom and side edges  56 ,  58 ,  60  of the sheet  54  may be captured by the frame  62 . Side portions  64  of the frame  62  capture at least a portion of the side edges  60  of the sheet  54  and are received within the opposing slots  18  in drop-down fashion. By “drop-down” assembly it is meant that the side portions  64  of each panel assembly  50  are aligned with the slots  18  and the panel assembly  50  is lowered between the posts  14  and within the slots  18  to secure the panel assembly  50  to the vertically mounted posts  14 , as depicted in  FIG. 1 . While, in the embodiment shown, two panel assemblies  50  are disposed between each pair of posts  14 , it is contemplated that one or more panel assemblies  50  may be disposed between each pair of posts  14 . 
     The posts  14  may be part of an existing traffic noise barrier wall, with the existing wood or concrete panels  12  ( FIG. 1 ) being replaced with the panel assemblies  50 . Alternatively, the posts  14  may be designed specifically for use with the panel assemblies  50 . In the posts  14 , post flanges  66  extending from the sides of the posts  14  define each of the slots  18 . The width of the slots  18  is greater than the thickness “t” of the side portions  64  of the frame  62 , with sufficient clearance existing between the frame  62  and the post flanges  66  so that the side portions  64  slide within the slots  18  to allow the drop-down insertion of the panel assemblies  50  into the slots  18 . The posts  14  are mounted to a secure base, such as for example, the ground, a concrete platform, a traffic barrier or parapet, or the like. The posts  14  are formed from a rigid material such as, for example, concrete, steel, or wood. 
     In the embodiment shown, each frame  50  includes a top portion  68 , a bottom portion  70 , and side portions  64 , with each portion  64 ,  68 , and  70  capturing a portion of a respective top, bottom or side edge  56 ,  58 , or  60  of the sheet  54 . The ends of each of the portions  64 ,  68 , and  70  interface with the ends of adjacent portions  64 ,  68  and  70  at mitered joints  72 , which form corners of the frame  50 . The frame  50  is formed from a rigid material such as, for example, steel, aluminum, fiberglass, plastic and the like. Each mitered joint  72  may be welded, fastened, or otherwise joined to form a continuous, rigid frame  50  around the entire perimeter of the sheet  54 . 
     While frame  50  is shown as including side portions  64  and top and bottom portions  68  and  70  to capture at least a portion of four side edges  56 ,  58  and  60  of the sheet  54 , it is also within the scope of the invention for the frame  50  to only be present on two opposing edges of the sheet  54  or on three edges of the sheet  54 . For example, it is contemplated that frame  50  may include only side portions  64  without the top and bottom portions  68  and  70 . In this embodiment, only the side edges of the sheet  54  will be captured by the frame  50 . 
     Each sheet  54  is made from an acoustically absorptive and/or reflective material that is appropriate for the individual application of the traffic noise barrier wall  48 . For example, sheet  54  may be made of a transparent material where it is desired that travelers on a roadway, railway, aircraft runway, waterway, parking lot, or walkway, adjacent to the wall  48  have a view through the wall  48 . One example of a preferred transparent material for use as sheet  54  is PARAGLASS SOUNDSTOP® acrylic sheet commercially available from CYRO Industries, 100 Enterprise Drive, Rockaway, N.J. Where transparency is not desired, other materials such as wood, steel, opaque acrylic, plastic, and the like, may be used. The sheet  54  may be corrugated or otherwise shaped for added strength. 
     Referring now to  FIG. 4 , a cross sectional view of the post  14  and side portions  64  of adjacent frames  62  is shown. Each side portion  64  includes a base portion  80  disposed outside the respective side edge  60  of the sheet  54 . Flanges  82  project from the base portion  80  on opposite sides of the sheet  54 . The base portion  80  and the flanges  82  form a channel for capturing the side edge  60  of the sheet  54 . An elastomeric gasket  84  may cover the side edge  60  of the sheet  54  within the channel to secure the sheet  54  within the channel. The base portion  80  and the flanges  82  are received in the slot  18 . As shown in  FIG. 2 , the flanges  82  may extend along the entire side edge  60  of the sheet  54 . 
     Disposed between each of the flanges  82  of the side portions  64  and the post  14  is an elastomeric gasket  86 . The elastomeric gasket  86  takes up any space between the flanges  82  and the post  14 . 
     In dimensioning the frame  50  for a particular application, the thickness “s” of the sheet  54  and the thickness “f” of the flanges  82  can be selected to provide the necessary overall thickness “t” of the frame  50  for the particular application. For example, where the panel assembly  50  is to replace a wood or concrete panel that is thicker than the sheet  54 , the thickness “f” of the flanges can be selected such that the overall thickness “t” of the frame  62  is equal to the thickness of the wood or concrete panel that it is to replace. The thickness “s” of the sheet  54  may be substantially less than the width of the slots  18 . By “substantially” less than the width of the slots  18 , it is meant that the thickness of the sheet  54  is less than 50% of the maximum width of the slots  18 , and more preferably less than 30% of the thickness of the slots  18 . For example, the maximum width of the slots  18  may be about 4 inches to about 5 inches for accepting a standard wood or concrete panel, and the thickness “s” of an acrylic sheet  54  may be about one inch. 
     Because the frame  62  supports a relatively thin sheet  54 , the panel assembly  50  is much lighter than the wood or concrete panel that it is to replace. As a result, the load applied by the panel assembly  50  to the posts  14  is less than that which would be applied by the wood or concrete panel. Because the load is less, a greater number of panel assemblies  50  can be used in place of the concrete or wood panels. In other words, if it becomes necessary to increase the height of the wall  48 , the concrete or wood panels can simply be removed and replaced with a greater number of panel assemblies  50 . If the height of the posts  14  is insufficient to accommodate the increased number of panel assemblies  50 , extensions can be added to the tops of the posts  18  to support the increased number of panel assemblies  50 . In any case, because the panel assemblies  50  are lighter than the wood or concrete panels, the wood or concrete panels can be replaced without having to perform the costly procedure of removing and replacing the posts  14 . 
     Referring to  FIG. 5 , a cross-sectional view of a bottom portion  70  of one panel assembly  50  is shown proximate a top portion  68  of another panel assembly  50 . Such an arrangement may occur when two or more panel assemblies  50  are disposed between a single pair of posts  14 , as shown in  FIG. 2 . Comparison of  FIGS. 4 and 5  shows that the cross-section of the side portions  64  of  FIG. 4  are substantially similar to the cross-section of the top and bottom portions  68 ,  70  of  FIG. 5 . It is contemplated that each of the portions  64 ,  68  and  70  of the frame  62  are substantially similar in construction, with each having a base portion  80  with flanges  82  extending therefrom, and with the associated edge  56 ,  68 , or  60  of the sheet  54  being captured between the flanges  82 . 
     In the embodiment of  FIGS. 4 and 5 , the flanges  82  are each formed from tubing, which is coupled by welding, fasteners, or the like to a plate that forms the base portion  80 . Preferably, the materials used to make the flanges  82  are the same for each of the top, bottom, and side portions  68 ,  70  and  64  of the frame  62 . That is, a single type of tubing can be cut as needed to form the flanges  82  for any portion of the frame  62 . Similarly, the plate used to make the base portion  80  is preferably the same for each of the top, bottom, and side portions  68 ,  70  and  64  of the frame  62 . Using the same materials for each of the top, bottom, and side portions  68 ,  70 , and  64  of the frame  62  allows manufacturing costs of the frame  62  to be reduced. It is also contemplated that to further reduce the manufacturing cost of the frame  62 , the flanges  82  can be pre-assembled to the plate that forms base  80 , and the entire assembly cut as needed to form any of the top, bottom, or side portions  68 ,  70  and  64  of the frame  62 . 
       FIGS. 6 and 7  depict an alternative construction of frame  62 . In the embodiment of  FIGS. 6 and 7 , each of the top, bottom, and side portions  68 ,  70  and  64  of the frame  62  are formed by extruding, molding, forging or otherwise shaping a single piece of metal to obtain a unitary structure including the flanges  82  and base portion  80 . Similar to the embodiment of  FIG. 5 , the flanges  82  and the base portion  80  can be pre-formed for use in any of the top, bottom, and side portions  68 ,  70  and  64  of the frame  62 . The formed material can then be cut as needed for any of the portions of the frame  62 . 
     Referring to  FIGS. 5 and 7 , each panel assembly  50  may include a means for interlocking with an adjacent panel assembly  50  to prevent relative movement of the panel assemblies  50  when they are stacked between posts  14 . In the embodiment of  FIG. 5 , for example, the top portion  68  of one frame  50  and the bottom portion  68  of an adjacent frame  50  each includes a protrusion  90  extending therefrom. The protrusion  90  on the top portion  68  is positioned on one side of its associated base  80 , and the protrusion  90  on the bottom portion  70  is positioned on the opposite side of its associated base  80 . Each protrusion  90  extends higher than the plate forming its associated base  80  such that when the bottom portion  70  from one panel assembly  50  rests on the top portion  68  of another panel assembly  50 , the protrusions  90  capture the plate assemblies there between to prevent relative lateral movement of the panel assemblies  50 . 
     The interlocking means of  FIG. 7  includes a pair of protrusions  92  extending from the bottom portion  70  of the frame  62  in one panel assembly  50 , and a single protrusion  94  extending from the top portion  68  of the frame  62  in an adjacent panel assembly  50 . The single protrusion  94  extends between the pair of protrusions  92  when the bottom portion  70  from one panel assembly  50  rests on the top portion  68  of the other panel assembly  50  to prevent relative lateral movement of the panel assemblies  50 . In either the embodiment of  FIG. 5  or  FIG. 7 , the protrusions  90 ,  92  and  94  may extend along the entire length of the top and/or bottom portions  68 ,  70  of the frames  62 . 
     Referring to  FIGS. 8 and 9 , a traffic noise barrier wall  48  including panel assemblies  100  in accordance with another embodiment of the present invention is shown. The noise barrier wall  48  includes spaced-apart, vertically mounted posts  14  having panel assemblies  100  extending between each pair of posts  14 . The panel assemblies  100  each include a sheet  54  of material having top  56 , bottom  58 , and side edges  60  forming a perimeter of the sheet  54 , and a frame  102  disposed around the perimeter of the sheet  54 . At least a portion of each of the top, bottom and side edges  56 ,  58 ,  60  of the sheet  54  may be captured by the frame  102 . Side portions  104  of the frame  102  capture at least a portion of the side edges  60  of the sheet  54  and are received within the opposing slots  18  in drop-down fashion. While, in the embodiment shown, two panel assemblies  100  are disposed between each pair of posts  14 , it is contemplated that one or more panel assemblies  100  may be disposed between each pair of posts  14 . 
     The posts  14  may be part of an existing traffic noise barrier wall, with the existing wood or concrete panels  12  ( FIG. 1 ) being replaced with the panel assemblies  100 . Alternatively, the posts  14  may be designed specifically for use with the panel assemblies  100 . In the posts  14 , post flanges  66  extending from the sides of the posts  14  define each of the slots  18 . The width of the slots  18  is greater than the thickness “t” of the side portions  104  of the frame  102 , with sufficient clearance existing between the frame  102  and the post flanges  66  so that the side portions  102  slide within the slots  18  to allow the drop-down insertion of the panel assemblies  100  into the slots  18 . The posts  14  are mounted to a secure base, such as for example, the ground, a concrete platform, a traffic barrier or parapet, or the like. The posts  14  are formed from a rigid material such as, for example, concrete, steel, or wood. 
     In the embodiment shown, each frame  102  includes a top portion  106 , a bottom portion  108 , and side portions  104 , with each portion  106 ,  108 , and  104  capturing a portion of a respective top, bottom or side edge  56 ,  58 , or  60  of the sheet  54 . The ends of each of the portions  104 ,  106 , and  108  interface with the ends of adjacent portions  104 ,  106  and  108  at mitered joints  72 , which form corners of the frame  102 . The frame  102  is formed from a rigid material such as, for example, steel, aluminum, fiberglass, plastic and the like. Each mitered joint  72  may be welded, fastened, or otherwise joined to form a continuous, rigid frame  102  around the entire perimeter of the sheet  54 . 
     While frame  102  is shown as including side portions  104  and top and bottom portions  106  and  108  to capture at least a portion of four side edges  56 ,  58  and  60  of the sheet  54 , it is also within the scope of the invention for the frame  102  to only be present on two opposing edges of the sheet  54  or on three edges of the sheet  54 . For example, it is contemplated that frame  104  may include only side portions  104  without the top and bottom portions  106  and  108 . In this embodiment, only the side edges of the sheet  54  will be captured by the frame  102 . 
     Each sheet  54  is made from an acoustically absorptive and/or reflective material that is appropriate for the individual application of the traffic noise barrier wall  48 . For example, sheet  54  may be made of a transparent material where it is desired that travelers on a roadway, railway, aircraft runway, waterway, parking lot, or walkway, adjacent to the wall  48  have a view through the wall  48 . One example of a preferred transparent material for use as sheet  54  is PARAGLASS SOUNDSTOP® acrylic sheet. Where transparency is not desired, other materials such as wood, steel, opaque acrylic, plastic, and the like, may be used. The sheet  54  may be corrugated or otherwise shaped for added strength. 
     Referring now to  FIG. 10 , a cross sectional view of the post  14  and side portions  104  of adjacent frames  102  is shown. Each side portion  104  includes a base portion  110  disposed outside the respective side edge  60  of the sheet  54 . Flanges  112  project from the base portion  110  on opposite sides of the sheet  54 . The base portion  110  and the flanges  112  form a channel for capturing the side edge  60  of the sheet  54 . An elastomeric gasket  114  may cover the side edge  60  of the sheet  54  within the channel to secure the sheet  54  within the channel. The base portion  110  and the flanges  112  are received in the slot  18  of post  14 . As shown in  FIG. 8 , the flanges  112  may extend along the entire side edge  60  of the sheet  54 . 
     In the embodiment depicted in  FIG. 10 , the base portion  110  has a generally triangular cross-section, with the flanges  112  extending from an apex of the triangle and with the base of the triangle forming the thickness “t” of the side portions  104  of the frame  102 . Disposed between each side of the base portion  110  and the post  14  is an elastomeric gasket  116 . The elastomeric gasket  116  takes up any space between the base portion  110  and the post  14 . 
     In dimensioning the frame  102  for a particular application, the thickness “s” of the sheet  54  and the thickness “t” of the side portions  104  can be selected for the particular application. For example, where the panel assembly  100  is to replace a wood or concrete panel that is thicker than the sheet  54 , the thickness “t” of the side portions  104  can be made equal to the thickness of the wood or concrete panel that the panel assembly  100  is to replace. As a result, the thickness “s” of the sheet  54  may be substantially less than the width of the slots  18 . 
     Because the frame  102  supports a relatively thin sheet  54 , the panel assembly  100  is much lighter than the wood or concrete panel that it is to replace. As a result, the load applied by the panel assembly  100  to the posts  14  is less than that which would be applied by the wood or concrete panel. Because the load is less, a greater number of panel assemblies  100  can be used in place of the concrete or wood panels. In other words, if it becomes necessary to increase the height of the wall  48 , the concrete or wood panels can simply be removed and replaced with a greater number of panel assemblies  100 . If the height of the posts  14  is insufficient to accommodate the increased number of panel assemblies  100 , extensions can be added to the tops of the posts  14  to support the increased number of panel assemblies  100 . In any case, because the panel assemblies  100  are lighter than the wood or concrete panels, the wood or concrete panels can be replaced without having to perform the costly procedure of removing and replacing the posts  14 . 
     Referring to  FIG. 11 , a cross-sectional view of a bottom portion  108  of one panel assembly  100  is shown proximate a top portion  106  of another panel assembly  100 . Such an arrangement may occur when two or more panel assemblies  100  are disposed between a single pair of posts  14 , as shown in  FIG. 8 . Each panel assembly  100  includes a means for interlocking with an adjacent panel assembly  100  to prevent relative movement of the panel assemblies  100  when they are stacked between posts  14 . In the embodiment of  FIG. 11 , the top portion  106  of one frame  102  and the bottom portion  108  of an adjacent frame  102  each includes a protrusion  120  extending therefrom and a recess  122  formed therein. The protrusion  120  on the top portion  106  is received within the recess of the bottom portion  108 , and vice-versa. 
     Comparison of  FIGS. 10 and 11  shows that the cross-section of the side portions  104  of  FIG. 10  are substantially similar to the cross-section of the top and bottom portions  106 ,  108  of  FIG. 11 . In the embodiment of  FIGS. 8-11 , the base portion  110  and flanges  112  may be formed by extrusion, molding, forging or otherwise shaping a single piece of material to form a unitary structure. It is contemplated that each of the portions  104 ,  106  and  108  of the frame  102  are substantially similar in construction, with each having a base portion  110  with flanges  112  extending therefrom, and with the associated edge  56 ,  68 , or  60  of the sheet  54  being captured between the flanges  112 . Similar to the embodiments of  FIGS. 5 and 7 , the base portion  110  and flange  112  structure can be pre-formed for use in any of the top, bottom, and side portions  106 ,  108 , and  104  of the frame  102 . The formed material can then be cut as needed for any of the portions of the frame  102 . Using the same materials for each of the top, bottom, and side portions  106 ,  108 , and  104  of the frame  102  allows manufacturing costs of the frame  102  to be reduced. 
     Referring to  FIGS. 12 and 13 , a traffic noise barrier wall  48  including panel assemblies  200  in accordance with yet another embodiment of the present invention is shown. The noise barrier wall  48  includes spaced-apart, vertically mounted posts  14  having panel assemblies  200  extending between each pair of posts  14 . The panel assemblies  200  each include a sheet  54  of material having top  56 , bottom  58 , and side edges  60  forming a perimeter of the sheet  54 , and a frame  202  disposed around the perimeter of the sheet  54 . At least a portion of each of the top, bottom and side edges  56 ,  58 ,  60  of the sheet  54  may be captured by the frame  202 . Side portions  204  of the frame  202  capture at least a portion of the side edges  60  of the sheet  54  and are received within the opposing slots  18  in drop-down fashion. While, in the embodiment shown, two panel assemblies  200  are disposed between each pair of posts  14 , it is contemplated that one or more panel assemblies  200  may be disposed between each pair of posts  14 . 
     The posts  14  may be part of an existing traffic noise barrier wall, with the existing wood or concrete panels  12  ( FIG. 1 ) being replaced with the panel assemblies  200 . Alternatively, the posts  14  may be designed specifically for use with the panel assemblies  200 . In the posts  14 , post flanges  66  extending from the sides of the posts  14  define each of the slots  18 . The width of the slots  18  is greater than the thickness “t” of the side portions  204  of the frame  202 , with sufficient clearance existing between the frame  202  and the post flanges  66  so that the side portions  202  slide within the slots  18  to allow the drop-down insertion of the panel assemblies  200  into the slots  18 . The posts  14  are mounted to a secure base, such as for example, the ground, a concrete platform, a traffic barrier or parapet, or the like. The posts  14  are formed from a rigid material such as, for example, concrete, steel, or wood. 
     In the embodiment shown, each frame  202  includes a top portion  206 , a bottom portion  208 , and side portions  204 , with each portion  206 ,  208 , and  204  capturing a portion of a respective top, bottom or side edge  56 ,  58 , or  60  of the sheet  54 . The ends of each of the portions  204 ,  206 , and  208  interface with the ends of adjacent portions  204 ,  206  and  208  at joints  209 , which form corners of the frame  202 . The frame  202  is formed from a rigid material such as, for example, steel, aluminum, fiberglass, plastic and the like. Each joint may be welded, fastened, or otherwise joined to form a continuous, rigid frame  202  around the entire perimeter of the sheet  54 . 
     While frame  202  is shown as including side portions  204  and top and bottom portions  206  and  208  to capture at least a portion of four side edges  56 ,  58  and  60  of the sheet  54 , it is also within the scope of the invention for the frame  202  to only be present on two opposing edges of the sheet  54  or on three edges of the sheet  54 . For example, it is contemplated that frame  202  may include only side portions  204  without the top and bottom portions  206  and  208 . In this embodiment, only the side edges of the sheet  54  will be captured by the frame  202 . 
     Each sheet  54  is made from an acoustically absorptive and/or reflective material that is appropriate for the individual application of the traffic noise barrier wall  48 . For example, sheet  54  may be made of a transparent material where it is desired that travelers on a roadway, railway, aircraft runway, waterway, parking lot, or walkway, adjacent to the wall  48  have a view through the wall  48 . One example of a preferred transparent material for use as sheet  54  is PARAGLASS SOUNDSTOP® acrylic sheet. Where transparency is not desired, other materials such as wood, steel, opaque acrylic, plastic, and the like, may be used. The sheet  54  may be corrugated or otherwise shaped for added strength. 
     Referring now to  FIG. 14 , a cross sectional view of the post  14  and side portions  204  of adjacent frames  202  is shown. Each side portion  204  includes a base portion  210  disposed outside the respective side edge  60  of the sheet  54 . Flanges  212  are formed as the ends of a generally U-shaped structure, which is attached to the base  210  by welding, fasteners, and the like. The generally U-shaped structure forms a channel for capturing the side edge  60  of the sheet  54 . An elastomeric gasket  214  may cover the side edge  60  of the sheet  54  within the channel to secure the sheet  54  within the channel. The base portion  210  is received in the slot  18  of post  14 . As shown in  FIG. 12 , the flanges  212  may extend along the entire side edge  60  of the sheet  54 . 
     In the embodiment depicted in  FIG. 114 , the base portion  210  of the side portions  204  is formed from a generally rectangular tube, with the U-shaped structure forming the flanges  212  attached to a planar side of the tube. The thickness “t” of the side portions  204  of the frame  202 . Disposed between each side of the base portion  210  and the post  14  is an elastomeric gasket  216 . The elastomeric gasket  216  takes up any space between the base portion  210  and the post  14 . 
     In dimensioning the frame  202  for a particular application, the thickness “s” of the sheet  54  and the thickness “t” of the side portions  204  can be selected for the particular application. For example, where the panel assembly  200  is to replace a wood or concrete panel that is thicker than the sheet  54 , the thickness “t” of the side portions  204  can be made equal to the thickness of the wood or concrete panel that the panel assembly  200  is to replace. As a result, the thickness “s” of the sheet  54  may be substantially less than the width of the slots  18 . 
     Because the frame  202  supports a relatively thin sheet  54 , the panel assembly  200  is much lighter than the wood or concrete panel that it is to replace. As a result, the load applied by the panel assembly  200  to the posts  14  is less than that which would be applied by the wood or concrete panel. Because the load is less, a greater number of panel assemblies  100  can be used in place of the concrete or wood panels. In other words, if it becomes necessary to increase the height of the wall  48 , the concrete or wood panels can simply be removed and replaced with a greater number of panel assemblies  200 . If the height of the posts  14  is insufficient to accommodate the increased number of panel assemblies  200 , extensions can be added to the tops of the posts  14  to support the increased number of panel assemblies  200 . In any case, because the panel assemblies  200  are lighter than the wood or concrete panels, the wood or concrete panels can be replaced without having to perform the costly procedure of removing and replacing the posts  14 . 
     Referring to  FIG. 15 , a cross-sectional view of a bottom portion  208  of one panel assembly  200  is shown proximate a top portion  206  of another panel assembly  200 . Such an arrangement may occur when two or more panel assemblies  200  are disposed between a single pair of posts  14 , as shown in  FIG. 12 . The base portion  210  of each of the top and bottom portions  206 ,  208  is formed from a flat plate, with the U-shaped structure forming the flanges  212  attached to a planar side of the plate. Each panel assembly  200  includes a means for interlocking with an adjacent panel assembly  200  to prevent relative movement of the panel assemblies  200  when they are stacked between posts  14 . In the embodiment of  FIG. 15 , the means for interlocking is substantially similar to that described with reference to  FIG. 7 , wherein a single protrusion  94  extends between a pair of protrusions  92  when one panel assembly  200  rests on the other panel assembly  200 . 
     The panel assemblies  50 ,  100 , and  200  described herein provide many advantages over panels used in prior art traffic noise barrier walls. The panel assemblies  50 ,  100 , and  200  are of relatively lightweight when compared to the wood or concrete panels typically used in traffic noise barrier walls. As a result, the panel assemblies  50 ,  100 , and  200  allow existing systems to be expanded without having to replace the existing posts and without sacrificing the structural integrity of the existing posts. Also, the frames  62 ,  102 , and  202  of the panel assemblies  50 ,  100 , and  200  are designed to receive any number of different sheets  54 , which may include transparent sheets, thus allowing for flexibility in the type of barrier used in the wall. The replacement of existing wood or concrete panels can be accomplished without modification of the posts  14 , using the same drop-down assembly technique. Referring now to  FIGS. 16-19 , some embodiments of the disclosed subject matter include a traffic noise barrier wall  300 . Wall  300  includes a first vertically-mounted post  302 , a second vertically-mounted post  304  that is spaced apart from the first post, and first and second panel assemblies  306  and  307  extending between the first and second posts. First and second panel assemblies  306  and  307  include a frame  308  around an outer perimeter  310 . 
     First vertically-mounted post  302  includes a first slot  312  disposed therein. First slot  312  extends lengthwise along a side  314  of first post  302 . 
     Second vertically-mounted post  304 , which is spaced apart from first post  302 , includes a second slot  316  disposed therein. Second slot  316  extends lengthwise along a side  318  of second post  304 . 
     First panel assembly  306  and second panel assembly  307 , which extend between first and second posts  302  and  304 , include a sheet  320  of material having top  322 , bottom  324 , and side  326  edges forming outer perimeter  310  of the sheet. 
     Frame  308  is disposed along at least a portion of perimeter  310  of sheet  320  and includes top  328 , bottom  330 , and side portions  332 . Side portions  332  of frame  308  capture at least a portion of side edges  326  of sheet  320 . Side portions  332  of frame  308  are generally received within first and second slots  312  and  316  in drop-down fashion. As shown in  FIG. 17 , each of side portions  332  of frame  308  includes a base portion  334  disposed outside one of side edges  326  of sheet  320 . Base portion  334  has a substantially rectangular cross-section  336  and first and second flange portions  338  and  340  disposed on the base portion. First and second flanges  338  and  340  form at least a portion of a channel  342  for capturing side edge  326  of sheet  320 . At least base portion  334  is received in one of first and second slots  312  and  316 . 
     As shown best in  FIG. 18 , in some embodiments, a connecting bracket  350  is positioned between first and second panel assemblies  306  and  307 . Connecting bracket  350  includes a center portion  352  and two pairs  354 ,  356  of first and second flanges  358 ,  360  extending from opposite sides of the center portion. Center portion  350  typically has a substantially rectangular cross-section  362 . First and second flanges  358 ,  360  form at least a portion of a channel  362 ,  364  for capturing top and bottom edges  322  and  324  of sheets  306  and  307 . 
     Referring now to  FIG. 19 , some embodiments include a panel assembly that is similar to previously described embodiments but include frame  308  having a base portion  400 . Base portion  400 , which is disposed along one of side edges  326  of sheet  320  as described above, includes substantially square outside portions  402 ,  404  that are connected to define a central channel  406  and an overall substantially u-shaped cross-section  408 . Central channel  406  captures at least a portion of the side edges  326  of sheet  320 . Each of outside portions  402 ,  404  includes a connecting portion  410 . Connecting portion  410  typically has a substantially circular cross-section  412  for receiving fasteners such as screws or similar, but can also be configured in myriad other cross-sectional shapes depending on the particular fastener to be used. Connection portions  410  will typically be used to connect portions of frame  308 . 
     Referring now to  FIGS. 20-22 , some embodiments includes a panel assembly system for a traffic noise barrier wall as described above but including a frame  308  having a base portion  500  and interconnecting male and female portions  502  and  504 , respectively, defining a connecting bracket  505 . 
     Base portion  500 , which is disposed along one of side edges  326  of sheet  320  as described above, includes first and second flange portions  506  and  508 , respectively, projecting outward from the base portion on opposite sides of the sheet to define a channel  510  between the first and second flange portions. Channel  510  captures at least a portion of side edges  326  of sheet  320 . Base portion  500  typically has a substantially rectangular cross-section  512 . At least base portion  500  is received in one of first and second slots  312 ,  314 . 
     In some embodiments, connecting bracket  505  is positioned between first and second panels  306  and  307 . Connecting bracket  505  includes male and female portions  504 ,  502 , each having a substantially triangular cross-section  514 . Male portion  504  includes a protruding portion  516  and female portion includes a recessed portion  518  that mates with the protruding portion. Each of male and female portions  504 ,  502  includes first and second flanges  520  and  522 , respectively, that extend from sides  524  and  526 , respectively, opposite of protruding and recessed portions  516 ,  518 . First and second flanges  520 ,  522  form at least a portion of a channel  528  for capturing top and bottom edges  322 ,  324  of sheets  520 . 
     Referring now to  FIG. 23 , some embodiments include a method of assembling a panel assembly for a traffic noise barrier wall of the type including opposing slots formed in pairs of vertically-mounted posts. The method includes first providing at least two panels of material having top, bottom, and side edges forming a perimeter of each panel. Then, joining a frame including top, bottom, and side portions around the perimeter of each panel. Next, temporarily connecting to the top portion of a first one of the at least two panels and placing the first one of the at least two panels between one of the pairs of vertically-mounted posts so that the side portions of the first one of the at least two panels are retained within the slots of the posts. The top portion is released after the first one of the at least two panels is positioned between the posts. Next, temporarily connecting to the top portion of a second one of the at least two panels and placing the second one of the at least two panels between the one of the pairs of vertically-mounted posts so that the side portions of the second one of the at least two panels are retained within the slots of the posts and the second one is positioned on top of the first one. The top portion is released after the second one of the at least two panels is positioned between the posts. Finally, the top portion of the second one (panel  307 ) of the at least two panels is removed so that a top edge  600  of is free of any frame portions. 
     A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.