The present invention concerns a roof structure and shelter that can be formed using said roof structure.

Blast- and/or ballistic-proof shelters are often required in remote locations with little infrastructure, particularly in military contexts. Any such shelter must therefore be easily transported and erected, preferably by two people, while still providing sufficient blast and/or ballistic protection.

One such blast- and/or ballistic-proof shelter is disclosed in W0200813921 1 . This shelter comprises a roof structure made from parallel beams that form a shallow arch, with tray members extending between each beam. This modular system allows the shelter to be easily transported.

A similar shelter is disclosed in WO2010052484. This shelter comprises a roof structure made from parallel beams that are archless, such that the beams have the same height at the supports as away from the supports, with tray members extending between each beam. This modular system allows the shelter to be easily transported.

US3206896 and US3820294 also disclose a shelter comprising parallel beams and tray members positioned thereon.

US5613453 discloses a double-walled explosion chamber, in which I-beams are positioned between the double walls of the chamber and surrounded by a fill material.

However, these shelters are complicated to erect due to the multiple component parts and the filling and positioning of each tray member required, which must be done tray- by-tray while the roof structure is being built. Dismantling these arrangements is also difficult. Further, additional supports are generally required to support the beams over their length, as simply resting one end of the beam on each outer support is not sufficient to create a blast- and/or ballistic-proof shelter. Thus, there is required a roof structure that can be used to form a shelter that addresses these problems.

According to a first aspect of the present invention, there is provided a roof structure comprising: at least two primary beams; at least two secondary beams, wherein the secondary beams extend across the primary beams and wherein at least one secondary beam is attached to at least one primary beam; a roof member, wherein the roof member is placed over and rests on the primary or secondary beams to create a substantially planar continuous surface; and a containment means provided on the roof member for containing a roof fill material supported thereon.

The arrangement of the present invention provides a roof structure for a modular shelter system in which each of the components are separately small and lightweight enough to be easily transported and erected. The roof structure can be assembled on the ground and then lifted into position, typically onto the pre-assembled outer walls of the shelter system. The modularity of the roof structure of the present invention also means that each of the components are individually not overly heavy and so the roof structure only requires two people to assemble it.

The shelter system for which the roof structure is designed typically comprises at least two spaced apart walls supporting in use opposed ends of the primary and/or secondary beams of the roof structure.

Once erected, the shelter system is sufficiently strong to hold a loose roof fill material and provide blast and/or ballistic resistance without requiring any additional support, beyond that provided by the shelter system walls, along the length of the beam. The roof fill material contained on the substantially planar continuous surface of the roof member and the overlapping primary and secondary beams provide blast and/or ballistic resistance to the shelter. The roof structure is therefore preferably blast- and/or ballistic-proof.

The shelter can also be easily dismantled, particularly due to the substantially planar roof member off which the roof fill material can simply be pushed once the containment means on the roof member has been at least partially removed. Specifically, the beams provide a flat surface onto which the roof member can be placed. The roof fill material can be easily removed from the roof member during dismantling the structure due to the substantially planar, continuous surface. This provides a significant advantage with respect to prior disclosures W0200813921 1 and WO2010052484 which contain roof fill material in individual tray members which must be emptied tray by tray.

At least two and preferably all of the primary beams may be parallel to one another. At least two and preferably all of the secondary beams may be parallel to one another. At least one primary beam may be perpendicular to at least one secondary beam. All of the primary beams may be perpendicular to all of the secondary beams. Preferably, there are more than three primary and/or secondary beams. Preferably, there are more than five primary and/or secondary beams.

These features provide multiple points at which the primary and secondary beams overlap, thereby improving the strength of the roof structure. Additionally, these features ensure that consistent blast and/or ballistic protection is provided over the entire area of the roof structure. Further, the overlapping beam arrangement means that the roof can be assembled on the ground and lifted into position.

A or each secondary beam may be attached to a primary beam, or to each primary beam. A or each primary beam may be attached to a or to each secondary beam. Attachment between primary and secondary beams (for example by any standard means such as bolt fastening) means that any point force, such as a blast or ballistic force, will be spread more evenly across the roof, thereby improving the strength of the shelter. This also increases the ease of lifting the roof structure into position once it has been assembled on the ground, and its removal when the shelter is decommissioned.

When the roof structure is assembled, the secondary beams may be above or below the primary beams. The roof member may rest directly on the primary beams or directly on the secondary beams. Preferably, the secondary beams may be attached to the opposite side of the primary beams to the side on which the roof member rests, such that the roof member rests on the primary beams. In this arrangement, the secondary beams are below the primary beams in the assembled roof structure.

The roof member may be attached to the primary or secondary beams. The roof member may be bolted to the beams or connected by any conventional means. This can ensure that the roof member is retained in position once the roof structure has been assembled.

The roof member may be substantially planar. The roof member may be planar. The roof member may be made from any suitable material, such as wood, plastic or metal. The roof member may be covered by a geotextile. The roof member may comprise a single member or multiple members that are connected together and/or to the primary or secondary beams to form a substantially planar continuous surface, most suitably without any indentations. The area of the substantially planar continuous surface may cover the entire area created by the primary and secondary beams and therefore be equal thereto. The area of the substantially planar continuous surface may cover the majority of the area created by the primary and secondary beams. The area of the substantially planar continuous surface may comprise the majority of the area created by the primary and secondary beams.

At least one of the secondary beams is attached to at least one of the primary beams. The secondary beam(s) may be bolted onto the primary beam(s). The secondary beam(s) may be connected to the primary beam(s) in any suitable manner. However, the connection should be sufficiently strong such that it does not affect the blast and/or ballistic resistance properties of the roof structure.

The primary and/or secondary beams may comprise any conventional type of beam. The primary and/or secondary beams may be the same or different. The primary and/or secondary beams may comprise more than one beam portion that are connected together to form a continuous beam, such that the first beam portion extends in the same direction as the second beam portion. The connection should be sufficiently strong such that it does not affect the blast and/or ballistic resistance properties of the roof structure. This further reduces the weight and length of the individual components of the roof structure, making it easier to transport and assemble.

The primary and/or secondary beams may comprise an l-shaped beam. The l-shaped beam may be formed from two C-shaped beams, each having three perpendicular straight portions wherein the two outer portions are parallel, thereby creating a C- shape. The ends of the two outer portions may be curved or straight. The C-shaped beams may be connected together along the middle portion of the three perpendicular portions of the C-shaped beam to create an l-shaped beam. l-shaped beams are stronger than other shapes of beam and therefore improve the blast and/or ballistic resistance of the roof structure. The use of two C-shaped beams to form an l-shaped beam means that each individual component is lighter weight and therefore easier to pack and transport. The lighter weight components can then be assembled on site. This can make it easier for only two people to construct the shelter.

There may be at least one spacer positioned between the two C-shaped beams that is connected to both of the C-shaped beams. Preferably, a plurality of spacers are present at intervals along the length of the beam. This broadens the beam and can strengthen the resulting I-beam and therefore the roof structure, while adding little additional weight.

The spacer preferably has at least two substantially planar surfaces that rest against the middle portion of each of the C-shaped beams. The spacer may be in the form of a hollow tube with a rectangular cross section. The spacer may be in the form of a solid means with a rectangular cross section. The spacer may be bolted to each C- shaped beam or may be connected in any other conventional manner. The spacer may have the same height as the C-shaped beams.

A spacer may be flush with the ends of the C-shaped beams, thereby creating a planar end to the l-shaped beam. This may be the case at both ends of the beams. Said spacer(s) may comprise a hole or other means to connect to an anchor means or another positioning means. Both the primary and secondary beams may comprise two C-shaped beams connected together to create an l-shaped beam with a spacer between the two C- shaped beams. A single spacer may extend from between the C-shaped beams of a primary beam to between the two C-shaped beams of a secondary beam and be connected to both the primary beam and the secondary beam. Said spacer may extend from the base of the secondary beam to the top of the primary beam and therefore have the same height as that of the two beams combined.

This helps to maintain the position of the secondary beams relative to the primary beams. This can also strengthen the arrangement without adding any additional weight. Further, this can prevent the beams from twisting relative to one another, thereby further increasing the strength of the roof structure.

The roof structure may further comprise an anchor means at one or both ends of the primary beams which extends perpendicular to the primary beams. The anchor means may connect at least two and preferably all of the beams together. The anchor means may provide additional support, may prevent the beams from moving relative to one another and may act to define the distance between at least two and preferably between all of the primary beams, such that said distance is consistent between each of the beams connected. The anchor means may also provide additional load sharing and may fill the spaces between the primary beams such that it prevents materials from entering the shelter formed from the roof structure. Preferably, the anchor means is present at both ends of the primary beams.

The anchor means may comprise a sheet or plate with defined positions at which the primary beams are connected. Said defined positions may comprise holes in the sheet or plate, which may only be present at the position at which the primary beams are connected. This helps to ensure that the primary beams have the same distance between them, thereby ensuring consistent blast and/or ballistic protection over the area of the roof structure, without significantly increasing the weight of the roof structure. The anchor means may only be connected to the primary beams. The containment means may comprise a plurality of gabions. The roof structure may further comprise a pre-detonation screen, which may be formed from a plurality of gabions.

According to a second aspect of the present invention, there is provided a roof structure comprising a roof member that creates a substantially planar continuous surface and a plurality of gabions provided on the roof member as a containment means for containing a roof fill material and/or as a pre-detonation screen.

Many of the advantages of the first aspect of the invention apply to the second aspect of the invention, particularly those relating to the roof member. The use of gabions as a containment means and/or as a pre-detonation screen provides a cheap, readily available and easily installable arrangement that provides good blast protection and is easily disassembled.

The walls of the gabions may be releasable. Thus, the fill material in the gabions can be easily removed for disassembly.

The roof member may be planar. The roof member may be made from any suitable material, such as wood, plastic or metal. The roof member may be covered by a geotextile. The roof member may comprise a single member or multiple members that are connected together to form a substantially planar continuous surface, most suitably without any indentations. The area of the substantially planar continuous surface may cover the entire area of the roof structure. The area of the substantially planar continuous surface may cover the majority of the area of the roof structure. The area of the substantially planar continuous surface may comprise the majority of the area of the roof structure.

The containment means are arranged such that they may contain a roof fill material supported on the roof member. The containment means may be placed directly on the roof member. This provides a simple arrangement for retaining a roof fill material on the roof member, which improves the blast and/or ballistic protection of the roof structure. The containment means may be releasable from the substantially planar roof member. The containment means may not be attached to the substantially planar roof member and may simply rest thereon. This means that dismantling the roof structure is easy, as the containment means can be removed and the roof fill material simply pushed off the substantially planar roof structure.

The containment means may extend around the perimeter of the substantially planar roof member. The containment means may extend around the majority of the substantially planar roof member. This ensures that all or a majority of the roof fill material is contained on the roof member and that the roof structure provides blast and/or ballistic protection over the entire area of the roof member.

The gabions of the containment means may be placed on the roof member while they are empty, before being filled with a material. The material may be the same as the roof fill material. This therefore provides a simple and easy way to contain the roof fill material, which requires few additional parts, is lightweight and can be constructed by two people.

The roof structure may further comprise a loose roof fill material supported on the substantially planar roof member. The loose roof fill material may comprise sand, stone, rubble or any other fill material that is available at the site of construction. This therefore provides a cheap and easy way to create a blast- and/or ballistic-proof roof structure.

The roof fill material may have a consistent depth over the entire area of the roof member. The depth is preferably from 50cm to 150cm. The depth of the roof fill material may be the same as, or slightly lower than, the height of the containment means.

The roof structure may further comprise a pre-detonation screen. The roof fill material may extend to the top of the containment means, such that together they create a substantially planar surface on which the pre-detonation screen can rest. The pre-detonation screen may extend over the majority of the area of the roof member, preferably over the entire area of the roof member. The plurality of gabions may be unfilled, may comprise no inner lining and/or may solely consist of metal baskets. The gabions may be foldable, preferably in a concertina manner. This provides a cheap, easy and lightweight way to create a pre-detonation screen.

A screen material may be placed on top of the plurality of gabions. This improves the pre-detonation action of the pre-detonation screen. This arrangement can ensure a constant pre-detonation screen over the entire area of the roof structure with a consistent height from the top of the roof structure, thereby ensuring consistent blast and/or ballistic protection. The use of gabions to create a pre-detonation screen provides a uniform structure that is easy to assemble and disassemble.

According to a third aspect of the present invention, there is provided a shelter comprising a first and a second outer wall and a roof structure as discussed above, wherein the roof member extends over both the first and second outer walls. The substantially planar continuous surface may extend over both the first and second outer walls. One end of each of the primary beams of the roof structure may rest on the first outer wall and the other end of each of the primary beams may rest on the second outer wall.

The first and/or second outer walls may be continuous along the length of the roof structure. The first and second walls may be parallel to one another and/or may be positioned between 2 and 5 metres apart.

The first and second outer walls may be sufficient to hold up the roof structure without the need for any other support along the length of the primary and secondary beams. This is in part due to the presence of both the primary and secondary beams, which increase the strength of the roof structure. This therefore creates a large, uninterrupted, versatile space within the shelter, as well as improving the ease of construction.

Alternatively, there may be a support member positioned between the walls to support the roof structure. The support member may comprise a frame comprising opposite upright supports and a transverse member extending between the upright supports, which supports the roof member. The transverse member may extend parallel to the walls. This allows the roof member to extend further distances without requiring an additional wall between the two outer walls.

The first and/or second walls may comprise a plurality of gabions. The gabion walls may comprise two or more rows of gabions resting on one another. The gabions may comprise supports such as an Acrow prop extending through their compartments. This can further increase the strength of the shelter.

The shelter may further comprise additional walls, which may extend between the first and second outer walls. These walls may connect to the secondary beams. The secondary beams are preferably not connected to the first and second outer walls.

The anchor means may be connected to the outer walls and/or to the supports within the outer walls. The anchor means may only be connected to the primary beams. The anchor means may run along the top or the side of the outer walls. This can help to ensure that the primary beams are fixed in position. The anchor means, particularly when in the form of a plate, can fill in the spaces between the roof structure and the outer walls such that material does not enter the shelter.

The shelter may further comprise a support means on which the primary beams rest, which extends along the majority of the length of the first or second outer wall. The support means may extend along the entire length of the first or second outer wall. The support means may be connected to at least one and preferably all of the primary beams. The support means may be connected to the supports such as Acrow Props and/or may be connected to the outer walls. The support means may extend along the top of the outer wall and/or along the side of the outer wall. The support means acts to transfer any force applied to the roof structure more evenly to the outer wall and may help to keep the primary beams in position.

The support means may be made from any rigid material, such as wood, metal or plastic. The support means are preferably planar and may be in the form of a sheet or board. The shelter of the present invention is preferably blast- and/or ballistic-proof. The shelter may withstand a 3kg explosion in contact with the roof fill material.

Two shelters may be positioned next to one another, such that the second wall of the first shelter also acts as the first wall of the second shelter. The roof structures of the first and second shelters may be connected to each other. The beams of the roof structures may be connected to one another, or the anchor means of the roof structures may be connected to one another.

According to a fourth aspect of the present invention, there is provided a kit for building the roof structure discussed above comprising at least two primary beams, at least two secondary beams, a roof member, wherein the roof member is operable to be placed over the primary and secondary beams to create a substantially planar continuous surface and a containment means, wherein the containment means is operable to contain a roof fill material supported on the roof member.

According to a fifth aspect of the present invention, there is provided a kit for building the roof structure discussed above comprising a roof member that is operable to create a substantially planar surface and a plurality of gabions operable to create a containment means for containing a roof fill material and/or a pre-detonation screen.

The kits contain lightweight, easily transportable components that can be readily assembled on site by two people to create a blast- and/or ballistic-proof shelter. The kits may additionally include any of the other components discussed above in relation to the first and second aspects of the present invention.

According to a sixth aspect of the present invention, there is provided a method of building the roof structure discussed above comprising the steps of arranging the at least two primary beams, arranging the at least two secondary beams to extend over the primary beams, connecting at least one of the secondary beams to at least one primary beam, placing the roof member over the primary and secondary beams, such that it rests on the primary or the secondary beams and forms a substantially planar, continuous surface and placing the containment means on the roof member.

The roof structure made using the method of the sixth aspect may have any of the features discussed above in relation to the first aspect.

According to a seventh aspect of the present invention, there is provided a method of building the shelter discussed above comprising the method steps of the sixth aspect and further comprising lifting the primary beams, secondary beams and roof member such that one end of each of the primary beams rests on a first outer wall and the other end of each of the primary beams rests on a second outer wall.

The containment means may be placed on the roof member before the roof member has been positioned on the first and second outer walls. This can make it easier to ensure that the containment means are located in the correct position. The containment means may be placed on the roof member after the roof member has been positioned on the first and second outer walls. This can make the roof structure easier to lift into place.

If the containment means comprise gabions, they can be placed on the roof member before or after the roof member has been positioned on the first and second outer walls, but are preferably only filled after the roof member has been lifted into position.

Alternatively, the primary beams may be positioned on the first and second outer walls, before being connected to the secondary beams. The roof member may then be placed over the primary and secondary beams, such that it rests on the primary or the secondary beams to form a substantially planar, continuous surface. The containment means may then be placed on the roof member. The fill material may then be placed on the roof member.

The shelter made using the method of the seventh aspect may have any of the features discussed above in relation to the first aspect. The invention will now be more particularly described with reference to the following examples and figures, in which:

Figure 1 a illustrates a shelter according to the present invention, without the containment means;

Figure 1 b illustrates the shelter of Figure 1 a, including the containment means;

Figure 1 c illustrates a shelter of Figure 1 b, including a fill material;

Figure 1 d illustrates a shelter of Figure 1 c, including a pre-detonation screen;

Figure 2 illustrates a shelter according to the present invention, without the containment means, with the outer walls shown in cross-section;

Figure 3 illustrates the connection between the roof structure and the outer walls of the shelter of Figure 2 in more detail;

Figure 4 illustrates a side view of the shelter of Figure 2;

Figure 5 illustrates a roof structure according to the present invention, without the containment means;

Figure 6 illustrates the arrangement of the primary and secondary beams in a roof structure according to the present invention;

Figure 7a illustrates a side view of the connection between the primary and secondary beams in a roof structure according to the present invention;

Figure 7b illustrates a perspective view of the connection of Figure 7a; and

Figure 8 illustrates a perspective view of a connection between a beam and an anchor member according to the present invention. Figure 1 a illustrates a shelter 1 comprising a first outer wall 2 and a second outer wall 3 opposite and parallel to one another. Primary beams 4 extend between the first and second outer walls. Connected to the underside of the primary beams 4 are secondary beams 5. Resting on top of the primary beams 4 is a roof member 6 made up of roof panels 6a, connected together to form a substantially planar, continuous surface. A third outer wall 7 is also present, extending most of the distance between the first and second outer walls.

Figure 1 b illustrates the shelter 1 of Figure 1 a, in which containment means 8 have been positioned on the roof member 6. The containment means comprises a single row of filled gabions, which extends around the perimeter of the roof member 6.

Figure 1 c illustrates the shelter 1 of Figure 1 b, in which a loose roof fill material 9 has been included on the roof member. The roof fill material 9 extends to the same height as the containment means 8 and therefore creates a substantially planar surface in combination with said containment means 8.

Figure 1 d illustrates the shelter 1 of Figure 1 c, including a pre-detonation screen 10. The pre-detonation screen 10 comprises unlined gabions 10a on top the roof fill material 9 and containment means 8. A screen 10b has been placed on top of the unlined gabions 10a.

Figure 2 illustrates a shelter 21 according to the invention, comprising a first outer wall 22 and a second outer wall 23 opposite and parallel to one another. Primary beams 24 extend parallel to one another between the first and second outer walls. Connected to the underside of the primary beams 24 are parallel secondary beams 25, extending perpendicular to the primary beams 24. Resting on top of the primary beams 24 is a roof member 26 made up of roof panels 26a, connected together to form a substantially planar, continuous surface.

Within the first outer wall 22 are Acrow props 27, which extend vertically through the compartments of the first outer wall 22. A support means 28 comprising a wooden board is connected to the top of the Acrow props 27, which extends along the length of the roof member 26 and rests on the top of the first outer wall 22. The primary beams 24 rest on the support means 28 and are attached thereto. The same arrangement is present in the second outer wall 23. In use, the compartments of the first and second outer walls will be filled with a fill material such that the Acrow props 27 are hidden from view.

The Acrow props 27 and the support means 28 provide additional strength and stability to the arrangement. The support means 28 also ensures that the primary beams 24 do not move relative to one another. The support means 28 may also help to position the primary beams at a constant distance from one another.

Figure 3 illustrates the arrangement at one end of the primary beams 24 in more detail. The secondary beams 25 extend perpendicular to the primary beams 24, underneath the primary beams 24, and are connected thereto. The roof member 26 is positioned on the opposite side of the primary beams 24 to the secondary beams 25.

The first outer wall 22 contains Acrow props (not shown) which extend vertically through the compartments of the first outer wall 22. A support means 28 is connected to the top of the Acrow props, extends along the length of the roof member 26 and rests on the top of the first outer wall 22. The primary beams 24 rest on the support means 28 and are attached thereto. The secondary beams 25 are not connected to the first outer wall 22 or the support means 28.

Figure 4 illustrates a side view of this arrangement, comprising the first outer wall 22 and the second outer wall 23 opposite one another. Primary beams 24 extend between the two outer walls and rest on support means 28 which is supported on the top of the outer walls and is attached to Acrow props within the walls (not shown). Secondary beams 25 extend perpendicular to the primary beams 24 and are connected thereto. A roof member 26 is attached to the primary beams 25 on the opposite side of the roof structure to the secondary beams 25.

Figure 5 illustrates the base of a roof structure according to the present invention, comprising primary beams 34, secondary beams 35 and a roof member 36. The primary beams 34 run parallel to one another and perpendicular to the secondary beams 35, which are also parallel to one another. The roof member 36 is on the opposite side of the primary beams 34 to the secondary beams 35.

The primary beams 34 and the secondary beams 35 are l-shaped beams formed from two C-shaped beams 37. Each C-shaped beam 37 is formed from three substantially straight portions perpendicular to one another, wherein the two outer portions are parallel, thereby creating a C-shape. The middle portions of the two C-shaped beams 37 are connected together to form an l-shaped beam, with spacers 38 between the two C-shaped beams 37 positioned at intervals along their length. The spacers 38 are bolted to the middle portion of the two C-shaped beams 37. The primary beams 34 have the same structure.

Figure 6 illustrates the arrangement of the primary beams 44 and the secondary beams 45 of the present invention in more detail. The primary beams 44 are positioned along the length of the secondary beam 45. The primary beams 44 are parallel to one another and perpendicular to the secondary beam 45. More than one secondary beam 45 will be attached to the primary beams 44 along their length.

The primary beams 44 comprise two C-shaped beams 47, separated by a spacer 48 to create an l-shaped beam. The l-shaped beam will comprise spacers 48 along its length. The secondary beam 45 will have the same structure.

Figure 7 illustrates a connection between a primary beam 54 and a secondary beam 55 according to the invention. Figure 7a illustrates a side view of the connection. Both of the primary beam 54 and the secondary beam 55 comprise two C-shaped beams 57 separated by a spacer 58 to create an l-shaped beam. The spacer 58 extends between the C-shaped beams 57 of the secondary beam 55 and between the C- shaped beams of the primary beam 54. The spacer is bolted to both the C-shaped beams of the primary beam 54 and the secondary beam 55 using bolts 59. The secondary beam 55 is also bolted to the primary beam 54 using bolts 60.

Figure 7b illustrates a perspective view of this arrangement. Spacer 58 can be seen extending between the C-shaped beams 57 of the primary beam 54 and is attached thereto using bolts 59. The spacer 58 also extends through the C-shaped beams 57 of the secondary beam 55. The secondary beam 55 is bolted to the primary beam 54 using bolts 60.

Figure 8 illustrates a beam comprising a first C-shaped beam 77a and a second C- shaped beam 77b, separated by a spacer 78. The spacer 78 is flush with the ends of the C-shaped beams, thereby creating a flat end to the l-shaped beam. The l-shaped beam abuts an anchor member 76 in the form of an index plate and is connected thereto via a fastening means 79 that extends through a hole in the spacer 78.