Abstract:
A blast protective barrier system, termed a blast wall, providing a security perimeter or boundary at and above a ground level definable in terms of an x, y, z coordinate system, includes several substantially ground level (xy plane) pile caps, each itself having a y-axis elongate length, a x-axis width, and a z-axis depth, the x-axis substantially defining the width of the barrier system. Each pile cap also includes an upper and lower xy plane surface, each of the upper surfaces including y-axis channels and each of the lower surfaces including several recesses. The system also includes a first, second and further modules having a plurality of opposing pairs of yz plane, the y-axis elongate concrete panels including opposing integral xz end cap elements having a high shock-absorptive structure for isolating each module from the effect of a blast upon an adjacent module.

Description:
REFERENCE TO RELATED APPLICATION 
   This application is a continuation-in-part of, and claims the benefit of, application Ser. No. 10/609,170, filed Jun. 30, 2003, entitled Blast Protective Barrier System, the entire content of which is expressly incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Area of Invention 
   The invention relates to protective barrier systems. 
   2. Prior Art 
   A long-standing concern with respect to terrorist attacks upon so-called soft targets has become that of the now well-known suicide bomb truck which is simply driven into such a target and then detonated. As such, a need has arisen for a barrier system having high blast and penetration resistance which may used in the protection of a wide variety of potential targets including, without limitation, oil tanks, harbors, and buildings of various types. Also, because most of such attacks originate from ground level, it is not necessary that the height of such a barrier system be equal to the height of the target to be protected. 
   The limited prior art which exists in the present area is reflected in U.S. Pat. No. 4,433,522 (1984) to Yerushalmi, entitled Blast And Fragment-Resistant Protected Wall Structure; U.S. Pat. No. 5,117,600 (1992) also to Yerushalmi, entitled Building Structure Having High Blast and Penetration Resistance; and U.S. Pat. No. 6,223,473 (2001) to Romig, entitled Explosion Relief System Including Explosion Relief Panel. Said reference to Yerushalmi &#39;600 is the most directly known precursor to the instant invention. Therein, a filling material such as loose sand, gravel, pebbles or stones is interposed between opposing concrete panels to form a basic barrier structure. The instant system therefore builds upon the invention of Yerushalmi &#39;600 in its provision of a more economic, modular and flexible system of blast barrier protection. 
   Other approaches to the problem of blast resistance have appeared in the form of special purpose fillers for placement within walls of structures and, as such, are reflected in U.S. Pat. No. 4,589,341 (1986) to Clark, et al entitled Method For Explosive Blast Control Using Expanded Foam; U.S. Pat. No. 4,763,457 (1988) to Caspe, entitled Shock Attenuating Barrier; and U.S. Pat. No. 5,214,894 (1993) to Glesser-Lott, entitled Wall Construction of a Non-Load Bearing External Wall. The instant invention thereby presents a system in which the void space between opposing panels may, in addition to the use of the loose filling materials taught by Yerushalmi &#39;600, also employ foam-like materials as is taught by Clark as well as cellular units having high viscous damping as is taught by Caspe above. Further, the instant system contemplates use of blast-resistant wall panel modules separated by frangible, blast-expansible, or blast isolation elements so that destruction of one module will communicate a shock wave to adjacent modules. 
   The prior art does not contemplate such a solution to the need for a blast-resistant security perimeter. 
   SUMMARY OF THE INVENTION 
   Taught herein is a blast protective barrier system, sometimes termed a blast wall, which is definable in terms of an x, y, z coordinate system. Said system includes a plurality of substantially ground level (xy plane) pile caps, each itself comprising an x-axis elongate length, a y-axis width, and a z-axis depth, said x-axis length substantially defining the width of the barrier system. Each pile cap also includes an upper and lower xy plane surface, each of said upper surfaces including y-axis channels and each of said lower surfaces including a plurality of recesses. The inventive system also includes a plurality of yz plane, y-axis elongate modules comprising pairs of vertical concrete panels having an x-axis width, each panel pair having a lower y-axis edge proportioned for press-fittable securement within said y-axis channels of said upper xy surfaces of said pile caps. Positioned between opposing pairs of concrete panels is a volume of high shock-absorbent material, which material may take a wide variety of different forms including, without limitation, loose sand, gravel, pebbles, stones, inflatable and non-inflatable foams, enclosed cellular units having properties of high viscous damping, and a variety of acoustical and thermal insulative materials which also possess properties of shock and blast absorption. The system further includes a plurality of elongate piles, each having upper ends thereof proportioned for securement within said recesses of said lower xy plane surfaces of said pile caps, whereby any one of said modular units, if subjected to a blast-related failure of the expansion spacer, thereby isolating the unit from the second or adjoining module, thus preserving the integrity of the rest of the system. Opposing xz plane surfaces of said modules may be secured to each other either through the use of said z-axis vertical elements or spaces, formed of shock-dispersing material, but re-barred to opposing xz surfaces of each module. 
   It is accordingly an object of the invention to provide a blast protective barrier system which will protect substantially any ground level target from a ground level attack including direct impact by a vehicle loaded with explosive. 
   It is another object to provide a blast protective barrier system having general utility in a wide variety of security applications and in which modules thereof may suffer destruction without substantial effect on adjacent modules of the system. 
   The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings, Detailed Description of the Invention and Claims appended herewith. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective fragmentary end view of the inventive system. 
       FIG. 2  is a vertical cross-sectional view taken along Line  2 - 2  of  FIG. 1   FIG. 3  is an enlarged vertical cross-sectional view of the pile cap shown in  FIG. 2 . 
       FIG. 4  is a horizontal cross-sectional view of a concrete panel of the system taken in the direction of Line  4 - 4  of  FIG. 1 . 
       FIG. 5  is a horizontal cross-sectional view showing one method of securement of opposing xz plane end faces of opposing panel pairs of the present system. 
       FIG. 6  is a top plan view of the vertical column shown in  FIG. 5 . 
       FIG. 7  is a foundation plan of the present system taken along Line  7 - 7  of  FIG. 1  and also showing a typical number of pile caps and associated structures associated with a single unit of the system. 
       FIG. 8  is a concrete barrier plan of the system taken along Line  8 - 8  of  FIG. 1  and showing the modular character of the units of system. 
       FIG. 9  is a top schematic view showing opposing xz plane end faces of opposing panel pairs using columns of blast isolation material and expansion and void spaces. 
       FIG. 10  is a top plan view showing the manner in which the inventive system may be used to protect selected structure. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to the perspective view of  FIG. 1 , the present inventive blast protective barrier system for providing a security perimeter or boundary at and above a ground level definable with reference to an x, y, z coordinate system (which is shown to the lower right of  FIG. 1 ). Therein, the subject system may be seen to include a plurality of substantially ground level (xy plane) pile caps  10 , each comprising a x-axis elongate length (see also  FIGS. 2 and 3 ), a y-axis width and a z-axis height. The length of each pile cap  10  substantially defines the width of the inventive system within the x-axis. As may be particularly noted, each pile cap  10  includes upper and lower xy plane surfaces  12  and  14  respectively. Said upper xy plane surfaces  12  exhibit y-axis channels, or grooves  16  into which concrete panels  18  and  20  (described below) are secured at between 5 and 15% of the height thereof. Within lower xy plane  14  of pile cap  10  are provided a plurality (preferably three) of recesses  22  into which are secured a corresponding plurality of piles  24 . In a preferred embodiment, a center pile  26  is aligned with the z-axis or gravity vector, while left and right piles  28  and  30  respectively are offset from the z-axis by an angulation falling in a range of about 15 to about 30 degrees. 
   As may be noted in  FIGS. 1 and 3 , pile cap  10 , after securement to its piles  26 ,  28  and  30  is constructed as driven or augercast piles, and then back-filled so that earth  32  is then compressed about the piles and pile caps forming a stable foundation for the structure as below described. 
   As above noted, the inventive blast protective barrier system includes said yz plane, y-axis panels  18  and  20 , each of which defines a module. In another embodiment, a third panel placed medially between said panels  18  and  20 . As may, more particularly, be noted in  FIG. 4 , each panel  18  or  20  is defined by an x-axis width and a y-axis length having a length-to-width ratio of approximately 12 to 1. A preferred x-axis width of panel  18  or  20  is about 12 inches (30 cm). Said panels  18  and  20  are also characterized by the use of vertical rebars  34  and of horizontal, xy plane rebars  36 . The function of the vertical rebars is that of reinforcement of the concrete of which panels  18  and  20  are typically formed. The primary function of horizontal rebars  36  is to permit z-axis elongate columns  38  to be poured between opposing xz plane surfaces  40  of panels  18  and  18 . 1 , and  20  and  20 . 1 . Said xz columns  38  are preferably formed of a material having a lesser density than that of panels  18 / 20 , to thus provide a path of least resistance to a blast or shock wave to which the system may be subjected. The purpose of this strategy is to preserve the integrity of wall modules of panels  18 / 20  not directed subject to attack. A column  38  may take the form of an expansion joint  48  that may comprise a foam-like shock absorbent material, partial void space or any combination that blast-isolates one module from another. Said columns may be positioned and strengthened by the use of re-bars  36 . 1 / 42 . Said columns  38  are shown in top, xy plane view in  FIGS. 5 and 6  as are vertical rebars  36 . 1 / 42  within each column  38 . To provide for appropriate x-axis offset between opposing ends of panels  18  and  20 , each column  38  will typically exhibit a z-axis dimension having a ratio of about 5 to 1 relative to the x-axis dimension of each panel  18 / 20 , thereby allowing a void space in a range of about 45 to about 50 inches (about 125 cm) between each panel  18  and  20 . See  FIGS. 1 ,  7  and  8 . 
   Between concrete panels  18  and  20  is provided a volume of high shock-absorbent material such as loose sand, dirt, gravel, pebbles, special-purpose blast suppressing foam barriers, as is taught in U.S. Pat. No. 4,589,341 to Clark, and special shock attenuating cellular elements of the type taught in U.S. Pat. No. 4,763,457 to Caspe, et al. 
   With reference to  FIG. 7 , there is shown a foundation plan of the inventive system. Therefrom, it may be appreciated that a typical unit of the present blast protective barrier system will consist of pile caps  10 ,  10 . 1 ,  10 . 2 , and  10 . 3  and their above-described corresponding piles  24  and vertical panels  18  and  20  (see also  FIG. 8 ). 
   Expansion joint columns  38  are used for the joinder of opposing xz surfaces  40  (see  FIG. 5 ) of panels  18 / 20 . Rather, special columns  38  include spaces  48  for expansion as shown in  FIG. 9 . Said spaces assume the modularity of each panel pairs  18 / 20 . Said columns  38  may be furnished with various properties of blast isolation as set forth herewith. 
   It should be further appreciated that certain other salient dimensional relations exist in the above-described system. Therein, a xz plane of each pile cap  10  in cross-sections of panels  18 / 20  define a ratio of x-axis pile cap dimension to separation of an opposing panel in a range of about 2.5:1 to about 5:1, in which about 3.5:1 has been found to be preferable. Further, the x-axis length of each pile cap defines a ratio of between about 3:1 and about 1:1 relative to the x-axis width of each panel  18 / 20 . It is further noted that in an xz plane of each panel pair, inclusive of said interposed volume of shock absorbent material, total aggregate x-axis dimension of outer surfaces of said panels to said compacted material comprises an x-axis range of between about 2.5:1 and about 1.5:1. Preferably, and particularly for purposes of ease of production, each modules of panels  18  and  20  will be identical in width and other respects. It is further noted that a x-axis depth of lower ends  5 . 0  (see  FIG. 2 ) which are within said pile cap channels  16  will comprise a ratio in a range of about 0.05 to about 0.15 of the entire z-axis height of the panels  18 / 20 , in which the ratio 0.07 is preferable. 
   The depth of piles  24  within earth  32  will typically be within a range of about 10 to about 50 feet in which the separation of the tops  52  of each pile within said recesses of the pile cap may define an aggregate length of about 10 feet. As may be noted in  FIG. 6 , a ratio of column  38  y-axis length to x-axis width will define a range between about 3.5:1 and 2.2:1. As may be noted in  FIGS. 5 and 6 , the x-axis width of column  38  will typically slightly exceed the x-axis width of panels  18 / 20 . 
   It is further noted that the height of each modules of panel  18 / 20  are typically within a range of about 8 feet (21 cm) to about 15 feet (40 cm), thereby providing sufficient height to protect a terrorist target from the vehicle of considerable height that may be filled with explosives. 
   It has been also determined that the ratio of z-axis height of each modules of panel  18 / 20  to the x-axis length of each pile cap  10  may be approximately equal but, more particularly, will reflect a range of about 0.7:1 to about 1.2:1. Thereby, the foundation of the instant structure, in combination with the above-described piles  24  will afford enormous lateral stability to the present structure in the event of an explosive attack or a direct armored assault by a tank, tank artillery or other state of the art ground-to-ground artillery. The structure will of course also provide a defensive perimeter in the event that security personnel are available at the time of such attack. 
   As above noted (see  FIG. 2 ), the angulation of outer piles  28  and  30  relative to center piles  26  will generally fall within a virtual cylinder defined by the greatest x-axis dimension of pile cap  22 . However, where earth  32  is not sufficiently stable or if it is not feasible to dig deeply into the earth, the angulation of the outer piles relative to the center pile  26  may be increased substantially, as may the number of pile provided beneath each pile cap. 
   The above set forth ratios are deemed material and are deemed the best mode of practice of the invention. 
   The preferred construction method associated with the above system is: 
   1. Install piles  24  to the required depth to withstand gravity and lateral loads. 
   2. Construct pile caps  10  with grooves  16  on each side (full width or partial width) to receive pre-cast concrete wall panels 15 feet (40 cm) to 25 feet (64 cm) long. 
   3. Make pre-cast concrete panels  18 / 20  with extended rebars at each end and at bottom of panels with or without the extended rebar. 
   4. Set pre-cast panel within a groove of the pile cap and lock it in place. 
   5. Pour concrete connector wall between surfaces of wall panels on top of pile caps at each pile cap location. Use shape of inverted letter “I” to connect to both wall panels and foundation. 
   6. At every 100 feet (34 meters) to 120 feet (41 meters) provide expansion joint within the wall by construction of shape (double channel back-to-back), with an expansion joint  48  in which material or mechanical means are used to accommodate expansion and contact of individual modules withstand high pressure even if adjacent modules are destroyed. 
   7. Fill the space between the modules of wall panels  18 / 20  with loose sand or selected fill material to absorb impact. 
   8. Connect the top of the wall panels with the concrete slab with cast-in-place or pre-cast concrete panels to act as twin wall on one unit on top of the wall panels. 
   9. If only single panel wall is to be used, neither backfilling nor top slab is required. 
   While there has been shown and described the preferred embodiment of the instant invention it is to be appreciated that the invention may be embodied otherwise than is herein specifically shown and described and that, within said embodiment, certain changes may be made in the form and arrangement of the parts without departing from the underlying ideas or principles of this invention as set forth in the Claims appended herewith.