GB2529688A

GB2529688A - An apparatus for forming a structure

Info

Publication number: GB2529688A
Application number: GB1415301.9A
Authority: GB
Inventors: Simon Widdowfield
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-08-29
Filing date: 2014-08-29
Publication date: 2016-03-02
Also published as: WO2016030696A1; GB201415301D0

Abstract

There is provided an apparatus (1) for forming a structure. The apparatus comprises: frame members (10, 15) that are configured to interconnect with one another to form a frame defining an overall shape of the structure; textile sheets (TF, TB) configured to fix over the frame, to define a cavity into which a settable material may be poured; first ties (30) configured to connect between the frame members (15); and second ties (40) configured to connect between the first ties (30). The second ties (30) are further configured to connect to the textile sheets (TF, TB), the second ties configured to retain the textile sheets in place during the setting of the settable material.

Description

AN APPARATUS FOR FORMING A STRUCTURE

DESCRIPTION

The present invention relates to an apparatus for forming a structure, and in particular an apparatus for forming a structure using a settable material.

BACKGROUND OF THE INVENTION

Settable materials such as cement or concrete are commonly used to form structures. However, one of the problems with settable materials is that they require holding in position whilst they set. A known apparatus for forming a structure comprises wooden plates which are arranged to form a cavity. The settable material can be poured into the cavity and allowed to set. The apparatus can then be removed from the settable material after it has set, to leave the finished structure. Such apparatus may be referred to as a formwork, since it is used to form the size and shape of the structure.

One of the problems with known apparatuses for forming structures with settable materials is that the apparatuses are often heavy and/or bulky, and often require highly skilled operators to create and arrange in such a way that the cavity supports the settable material in the desired shape. For example, the forming of a structure using the known wooden plate method typically requires carpentry skills to form and connect the wooden plates together to provide the desired cavity.

As an alternative to wooden panels, it is known to use textiles which are lighter, and which may remain as part of the finished structure, rather than being removed. However, textiles are flexible and so typically flex under the pressure exerted on them by the settable material to maximise the volume of the cavities that the textiles define, reducing the number of applications for which textiles can be used. It is known to add rigid structures to constrain the flexing of the textiles, although such rigid structures may again require highly skilled operators to erect, similar to the known wooden plate method.

One of the applications of structures based on settable materials is in the creation of barriers for military uses, where heavy and/or bulky materials may be difficult to transport, and where skilled operators may be difficult to obtain in the country or location where the structure is to be formed.

Such barriers may be required to provide resistance to ballistic or explosive threats, complicating their design by adding reinforcements, and making the use of known methods of forming structures with settable materials even more problematic.

WO 2013/164602 discloses a method of erecting a reinforced enclosure, comprising a frame, rigid reinforcing members secured within the frame, and a plurality of panels secured to the rigid reinforcing members. A filler material such as concrete is poured between the panels. The panels are rigid and are said to be securable to the rigid reinforcement members. Although, the rigid reinforcing members and rigid panels are bulky and require significant space to transport.

Additionally a commercial implementation requires a falsework system to support the panels when liquid concrete is poured to a depth of more than 0.3m, requiring the height of the wall to be built up in 0.3m increments, and requiring skilled and experienced personnel to install the reinforcement and create the falsework.

It is therefore an aim of the invention to improve on known apparatuses for forming structures with settable materials.

SUMMARY OF THE INVENTION

According to an embodiment of the invention, there is provided an apparatus for forming a structure. The apparatus comprises: frame members that are configured to interconnect with one another to form a frame defining an overall shape of the structure; textile sheets configured to fix over the frame, to define a cavity into which a settable material may be poured; first ties configured to connect between the frame members; and second ties configured to connect between the first ties rather than the frame members. The second ties are further configured to connect to the textile sheets, the second ties configured to retain the textile sheets in place during the setting of the settable material.

The frame together with the first and second ties and textile sheets defines a cavity into which the settable material may be poured, the ties and frame retain the textile sheets in position against the hydrostatic forces exerted by the settable material during its setting. The settable material may set around the ties and within the textile sheets, so that the ties and textile sheets remain as part of the finished structure. The ties and textile sheets may add reinforcement to the settable material once it has set, to help the settable material resistant blasts or impacts.

The finished structure allows structural and high energy loads to distribute and develop throughout the entire structure, from the textile sheets, through the second ties, along the first ties, and to the framework.

The apparatus is easily transportable and deployable abroad, in areas away from established resources such as skilled labour and quality construction materials. Settable materials are readily available in most parts of the world and so are not normally comprised within the apparatus, although could be if desired.

The apparatus may be used to construct structures for building forms such as but not limited to foundations, walls, slabs, columns, arches, retaining and perimeter walls. The apparatus may also be used to construct structures for retro-fitting to existing buildings to improve their resistance to dynamic loads and impacts, for example ballistic impacts.

The frame members are typically rigid and provide a structural mount for the textile sheets and first and second ties, thereby providing resistance to tensile forces in the textile sheets and first and second ties which may occur during blasts or impacts. The frame members are preferably constructed from stiff materials having high tensile strengths, such as steel, aluminium, and/or glass reinforced plastics.

The frame members may be cellular, with the benefit of allowing the settable material to enter the frame members internally, to improve the strength of the frame members and improve resistance to buckling of the frame members under loading. For example, the frame members may be formed to include an open cell foam structure.

Advantageously, the first and second ties may be formed of flexible materials so that the ties can easily be rolled up for transportation. The textile sheets are also typically sufficiently flexible so that they can be folded and/or rolled up for transportation.

The first and second ties are potentially made up from any material with a high tensile strength that can be is simply connected to the mounting structural frame. For example, the first and second ties may be steel wire ropes, glass woven fabrics, cotton, flax nylon, polypropylene, polyester, aramid, dyneema, Kevlar etc. Preferably, the tensile strength of each first and/or second tie is at least MPa.

The first and second ties may be connected to the frame members with simple mechanical connections such as bolts, hooks, clamps, etc. The first and second ties may be ropes having strands that are torque and pre or post stressed to reduce elongation of the ties and help prevent slippage between the ties and the settable material once the settable material has set. Preferably, the Young Modulus of each first and/or second tie is at least 10 GPa.

The first ties may comprise two layers of first ties, the two layers being in parallel planes to one another, and the second ties may be connected to the first ties and span between the two layers, thereby transferring forces between the two layers under normal structural loads, blasts or ballistic impacts. Each layer may be a grid formed by a first set of first ties and a second set of first ties, the first and second sets of first ties being orthogonal to one another. Then, the second ties may be connected at crossing points between the first ties of the first set and the first ties of the second set, for example by looping around the first ties.

The second ties extending between the first ties help provide resistance to shearing of the structure and connect to the textile sheets to help retain the textile sheets in place during the setting of the settable material. Hydrostatic forces imposed upon the first and second ties by the weight of the settable material acting against the textile sheets to tension the first and second ties as the settable material sets.

Advantageously, the second ties may be connected directly to the textile sheets by simply inserting and looping the second ties through hoops that are woven into the textile sheets. Then one end of each second tie can be looped through the hoops and around the first ties, and attached to the other end of the second tie. The ends of the second tie may for example be attached to one another with a loop and hook arrangement.

The textile sheets may help prevent spalling of the structure following an impact against the structure, by preventing any spalls of the settable material from breaking away from the structure. As is known to those skilled in the art, spalling can occur when an impact on one side of a structure causes material of the structure to break and fly away from an opposite side of the structure, potentially injuring any persons near the opposite side of the structure.

Accordingly, the textile sheets preferably have a high resistance to tearing and/or bursting, to improve the overall strength of the structure by resisting tensile forces. Accordingly, the textile sheets are preferable formed of materials having high tensile strengths, for example cotton, flax, nylon, plastics, polypropylene, polyester, aramid, dyneema, Kevlar, etc. The textile sheets may be formed of multi-layer and three dimensional woven fibres.

The textile sheets may be porous to reduce blowholes and capillaries/cavities that form within the settable material due to trapped excess water and air that expels during curing. Reducing the blowholes and capillaries/cavities helps increase the ductility and durability of the finished structure.

The textile sheets may be fixed over the frame by connecting them between frame members. The textile sheets may be connected to the frame members by simple mechanical connections, for example zips, keder rails, bolted clamping plates, fabric rope and tube, lapped and sewn, fabric and foil seem, foil welded, etc. The use of simple mechanical connections between the first and second ties, textile sheets, and framework members means that the apparatus can be used to rapidly create a structure as and when required.

A settable material is typically considered to be a material which can flow prior to setting and which becomes rigid after setting. The settable material may for example be concrete, which is readily available in most countries of the world, although could alternatively be other materials such as cementitious or resinous grouts, sand/stills/gravels with cohesive agent, locally obtained earth with resins, etc. The settable material once it has cured may have a compressive strength ranging from approximately iON/mm2 to approximately 60N/mm2. The settable material may also range in ductility with higher values increasing the flexural and tensile performance of the system. Additives maybe added to the settable material such as straw, hair, synthetic, glass, steel fibres to increase its ductility and resistance to flexural, tensile, shear and breaching forces from conventional structural loadings and non-conventional high energy dynamic loadings.

The frame members may be configured to interconnect with one another to form a frame defining an overall shape of the structure, by being sized and shaped to fit together in a frame. The textile sheets may be configured to fix over the frame, by being sized to fit the frame, and/or by having attachments compatible with the frame. The first ties may be configured to connect between the frame members by having lengths sized to span between the frame members, and/or by having retainers that are compatible with the frame. The second ties may be configured to connect between the first ties by having lengths sized to loop around the first ties or attachments for attaching to corresponding attachments of the first ties. The second ties may be configured to connect to the textile sheets, by being sized to span between the textile sheets when the textile sheets are fitted to the frame, and/or by having attachments compatible with the frame. In some implementations, the textile sheets and first and second ties may be supplied on a continuous roll so that they can be cut to the correct lengths at the time of assembling the structure, and the apparatus may include suitable attachments for attaching them to one another.

DETAILED DESCRIPTION

Embodiments of the invention will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which: Fig. 1 shows a schematic perspective diagram of a apparatus for forming a structure according to an embodiment of the invention; Fig. 2 shows a schematic perspective diagram of the apparatus of Fig. 1 when connected together, in preparation for addition of a settable material; Fig. 3 shows a perspective schematic diagram of the apparatus of Fig. 2, with a front textile layer removed to show internal details of the apparatus; Fig. 4 shows a schematic perspective diagram of the apparatus of Fig. 2 being filled with a settable material, to create a blast resistant wall of a building; Fig. Sa shows a schematic perspective diagram of multiple apparatuses of Fig. 2 being used together to form a barrier wall; Fig. 5b shows a plan view of a part of the wall of Fig. 5a; Fig. 6 shows a schematic perspective diagram of multiple apparatuses of Fig. 2 being used together to form a watch tower; Fig. 7 shows a schematic cross-sectional diagram taken vertically down one of the apparatuses shown in Fig. 5; Fig. 8 shows a schematic cross-sectional diagram taken horizontally across one of the apparatuses shown in Fig. 5; Fig. 9 shows a more detailed view of part of the cross-section of Fig. B; and Figs. ba and lOb show a schematic diagram of a wall formed using the apparatus of Fig. 2, before and after impact by a shockwave.

S

The figures are not to scale, and same or similar reference signs denote same or similar figures.

The schematic diagram of Fig. 1 shows an apparatus 1 for forming a structure according to an embodiment of the invention. The apparatus comprises a left frame portion LEE', a bottom frame portion BPE, a right frame portion RPE, and a top frame portion TEE'. The left, bottom, and right frame portions are shown as being connected to one another at their ends, as a first step in forming a wall, although they would normally be disconnected from one another during transport and/or storage. The top frame portion TEP would be connected between the ends of the left and right frame portions that are opposite the ends where the bottom frame portion BFP is connected, in order to form a frame defining an overall shape of the structure.

Each one of the left, right, top, and bottom frame portions comprises two longitudinal frame members 10, and several transverse frame members 15 which connect between the two longitudinal frame members 10. The longitudinal frame members 10 and transverse frame members 15 are formed of aluminium.

The apparatus 1 further comprises first ties 30, which in this embodiment are flexible steel wire ropes terminated at each end with bolt retainers 31. The bolt retainers 31 each comprise a threaded rod and a bolt screwed on the threaded rod at a distal end of the rod. Only two first ties 30 are shown in Fig. 1 for clarity, although in practice there will be many more than only two first ties, the actual number depending on the structure that is to be formed. In alternate embodiments, the flexible steel ropes 30 could be substituted for other types of flexible ties that are strong under tension, and/or the retainers 31 could be substituted for other types of retainers. The retainers allow the ends of the first ties to connect to the frame members.

The apparatus 1 further comprises second ties 40, which in this embodiment are flexible steel wire ropes. Each flexible steel wire rope is formed into a loop by connecting its ends together with fasteners 42. For example, the fasteners 42 shown in Fig. 1 comprise small retainer loops which are looped through loops at each end of the flexible steel rope. Clearly, other types of fastener 42 may be used in alternate embodiments. Only three second ties 40 are shown in Fig. 1 for clarity, although in practice there will be many more than only three second ties, the actual number depending on the structure that is to be formed. In alternate embodiments, the flexible steel ropes 40 could be substituted for other types of flexible ties that are strong under tension, and/or the fasteners 42 could be substituted for other types of fasteners. The fasteners allow the ends of each second tie to be connected to one another, to form a loop for attaching to the first ties, and to textile sheets which are described directly below.

The first and second ties 30 and 40 are shown rolled up in Fig. 1, to reduce their overall size for storage and/or transport. In this embodiment, the first and second ties have a tensile strength of 100 MPa, and a Young Modulus of 1OGRa, although higher figures than these may be implemented to increase strength in alternate embodiments.

The apparatus 1 further comprises two textile sheets 20, one of the textile sheet being a front textile sheet TE for fixing to a front of the frame, the other textile sheet being a back textile sheet TB for fixing to a back of the frame. The textile sheets are each shown in Fig. 1 as being folded up in a concertina for storage/transportation, although could alternatively be rolled up. In this particular embodiment, each textile sheet 20 is formed of woven Aramid fibres, and is pre-cut to fit the shape of the frame. In this embodiment, the edges of the textile sheet are not provided with any attachment features for attaching to the frame, although in alternate embodiments attachments such as strips for sliding into grooves of the frame may be provided along the edges of the textile sheets.

The schematic diagram of Fig. 2 shows the apparatus 1 during its assembly for the formation of a structure, in this embodiment a wall. The frame members of the left frame portion LEP comprise front left and back left frame members 10 connected by left transverse frame members 15, and the frame members of the right frame portion REP comprise front right and back right frame members 10 which are connected by right transverse frame members 15. As shown in Fig. 2, the front textile sheet TF is connected between the front left and front right frame members, and the back textile sheet TB is connected between the back left and back right frame members.

The front textile sheet TF also connects to a front bottom frame member of the bottom frame portion BFP, and the back textile sheet TB also connects to a back bottom frame member of the bottom frame portion BEE'. The front bottom and back bottom frame members are connected by bottom transverse frame members.

The front and back textile sheets also connect to respective frame members of the top frame portion TEE', however the top frame portion TEE' has been omitted from the view of Fig. 2 so that the first ties 30 can be seen extending upwardly between the front and back textile sheets TF and TB.

The front and back textile sheets TE and TB together define a cavity CVTY into which a settable material such as concrete may be poured, to provide strength to the structure. In the Fig. 2 embodiment, a left textile sheet TL is connected between the front and back frame members of the left frame portion [ER, and a right textile sheet TR is connected between the front and back frame members of the right frame portion RFP. The left and right textile sheets help define the cavity GVTY, although are not essential if the left or right frame portions abut against an existing object that helps to define the cavity CVTY, for example another wall.

The schematic diagram of Fig. 3 shows the apparatus 1 partly assembled according to Fig. 2, but with most of the front textile sheet TF cut away so that the internal details of the assembly can be seen. As shown in Fig. 3, there are two grids of first ties 30 extending longitudinally along the wall, the grids being parallel to one another. A front one of the grids has first ties 32 which are connected between the left and right transverse frame members. The front one of the grids also comprises first ties 34 which are connected between the bottom transverse frame members and top transverse frame members, orthogonal to the first ties 32.

A back one of the grids has first ties 36 which are connected between the left and right transverse frame members. The back one of the grids also comprises first ties 38 which are connected between the bottom transverse frame members and the top transverse frame members, orthogonal to the first ties 36.

II

The first ties 32 and the first ties 34 cross one another at multiple crossing points XPF of the front grid, and the first ties 36 and the first ties 38 cross one another at multiple crossing point XPB of the back grid. The second ties 40 are connected transversely between the crossing points XPF and the crossing points XPB, by looping each second tie 40 around the two first ties 32 and 34 at a crossing point XPF of the front grid, and around the two first ties 36 and 38 at a crossing point XPB of the back grid, the crossing points XPF and XPB being directly opposite to one another, so that the second tie 40 is orthogonal to all the first ties 30. The second ties 40 prevent the front and back grids from separating from one another, and the second ties 40 are also connected to the front and back textile sheets TF and TB to prevent the textile sheets from separating from one another, as will be explained in more detail later on with reference to Fig. 9.

The first ties 30 are connected to the transverse frame members 15 by the bolt retainers 31, specifically the threaded rod of each bolt retainer is passed through a hole in the required transverse member, and secured by the bolt of the bolt retainer 31 at an opposite side of the hole from the first tie. The second ties 40 are looped around the first ties and the ends of each second tie fastened together by the fasteners 42.

The schematic diagram of Fig. 3 shows the apparatus 1 when it is partly, rather than fully, assembled. Accordingly, Fig. 3 only shows the first four of five first ties 32 between the left and right transverse frame members, the first four of five first ties 36 between the left and right transverse frame members, and the first twelve of forty-five second ties 40 between the forty-five crossing points XPF and the forty-five crossing points XPB.

The schematic diagram of Fig. 4 shows the fully assembled apparatus 1 during filling of the cavity CVTY with a settable material 50, in this embodiment concrete. The top frame member is omitted from Fig. 4, so that the concrete 50 can be more easily seen. The apparatus 1 is being used to help form a wall 62 of a building 60. The wall 62 is built upon a floor 61, and is separated from another wall 63 by a window 65. The frame members 10 and 15 are all tubular and each have

U

cells 18 which are formed as holes through the sides of the tube. Accordingly, the concrete 50 can enter the cells 18 through the holes, increasing the strength of the frame members when the concrete sets. The textile sheets 20 are porous so that water can escape through them during the setting of the concrete 50.

As an alternative to forming building structures, the apparatus 1 may also be used to form barrier structures, for example the barrier structure 75 shown in the schematic diagram of Fig. 5a. The barrier structure 75 comprises nine walls 70 adjoining one another, each of the walls 70 formed using respective apparatuses 1, and formed upon a base structure 78. Lifting hooks 58 are embedded in the concrete 50 at the tops of the walls 70, so that the walls 70 can easily be lifted.

In this barrier structure embodiment, the apparatus 1 comprises left and right transverse frame members each having two sub-members that are placed at different longitudinal locations, to form interlocking portions so that the walls 70 can interlock with one another. Specifically, Fig. 5a shows an interlocking portion EX1 at an end of one of the walls 70, and Fig. Sb shows a plan diagram of the interlock EX1. It can be seen on Fig. Sb that the interlock is formed by splitting the transverse members 15 into two sub-members 15_i and 1 5_2 which are offset from one another along the length of the wall 70.

The apparatus 1 may be sized to form a wide variety of structures, for example a watch tower structure 85 is shown in the schematic diagram of Fig. 6.

The watch tower 85 is built upon a concrete base 88, and has multiple individual structures 80 formed by respective apparatuses 1. The individual structures 80 are sized to provide spaces for a door 82 and windows 84. Each of the structures 80 is resistant to blast impulses of greater than 2500 kPa-msec and blast pressures of greater than 1000 kPa. Each of the structures 80 is also resistant to blasts in excess of level D5 Bag I Suitcase, 20 kg Explosives, as defined in NATO Standardisation Agreement (STANAG) 2280 -Design Threat Levels and Handover for Temporary Protective Structures (Edition 1, 2008). Accordingly, each structure 80 may be considered to be a blast resistant wall. 1-, Ii

The schematic diagram of Fig. 7 shows a vertical cross-section through one of the walls 70, which is taken looking in along line CXS1 marked on Fig. 5a. It can be seen that the first ties 30 are connected between transverse frame members 15 of the top frame portion TFP and the bottom frame portion BFP. The front and back textile sheets TF and TB are connected between the longitudinal frame members 10 of the top frame portion and the bottom frame portion TFP and BFP, and are filled with concrete 50 in between them. The concrete 50 comprises cement and an aggregate 55, in this embodiment stone chippings.

The schematic diagram of Fig. 8 shows a horizontal cross-section through one of the walls 70, which is taken looking in along line CXS2 marked on Fig. 5a. It can be seen that the first ties 30 are connected between transverse frame members 15 of the left frame portion [FR and the right frame portion RFR. The front and back textile sheets TF and TB are connected between the longitudinal frame members 10 of the left frame portion and the right frame portion LFP and RFP, and are filled with concrete 50 in between them.

It can been seen in Fig. 8 that the second ties 40 are connected to the textile sheets TF and TB by hoops 22, retaining the textile sheets in place against the hydrostatic pressure exerted on the textile sheets by the concrete 50 during its setting. This hydrostatic pressure can be considerable, especially for high structures where a large head of un-set (liquid) concrete is constrained between the textile sheets, and the ties 40 need to be sufficiently strong in tension to resist this pressure. The hydrostatic pressure causes the textile sheets to bulge outwardly in the regions between the second ties 40, as shown.

The schematic diagram of Fig. 9 shows an enlarged view of part of the cross-section of Fig. 8. In this enlarged view, it can be seen that the each textile sheet 20 (TF and TB) is formed from two woven layers 25 and 26 of Aramid material, which are interlaced with one another by Aramid threads 24. Each textile layer also comprises Aramid hoops 22, which are positioned to co-incide with the crossing points XPF and XPR (see Fig. 3), so that the second ties 40 can be looped through them to secure the two textile layers TF and TB together. The second tie 40 shown in Fig. 9 has a fastener 42 in the form of a loop and hook

N

fastener, so that the ends of the second tie 40 can be passed around the first ties and through the hoops 22, and then secured to one another.

In alternate embodiments, the textile sheets TF and TB may have an alternate construction, and the hoops 22 may be replaced by other types of attachment points, for example hooks or clips. Furthermore, many more hoops/hooks/clips could be provided in the textile sheets than those required to connect to second ties, since the settable material will surround the free hoops/hooks/clips and help anchor the textile sheet in the settable material once it sets. In alternative embodiments, each second tie 40 could be linear, rather than looped, and could be provided with attachments for attaching to the first ties and the textile sheets.

An example of how the apparatus 1 allows formation of walls having high structural strength will now be discussed with reference to Figs. iDa and lOb. Fig. 1 Oa shows a portion 90 of a wall formed with the apparatus 1, and Fig. 1 Ob shows the portion 90 whilst it is being impacted by an explosive shockwave 94. The explosive shockwave 94 bends the wall away from the frame, causing cracks 96 in the concrete 50. The first tie 30 at the opposite side of the wall from the shockwave 94 is in tension, helping to limit the number of cracks 96 that form, and the second ties 40 help to prevent cracks forming along the length of the wall, helping prevent shearing of the wall. The cracks result in the formation of a fragment 98 of concrete, however the fragment is prevented from spalling away from the wall by the textile layer 20 at the opposite side of the wall from the shockwave 94, protecting any people/objects from being hit by the fragment 98.

Many other variations of the described embodiments falling within the scope of the invention will also be apparent to those skilled in the art.

Claims

CLAIMS1. An apparatus for forming a structure, the apparatus comprising: frame members that are configured to interconnect with one another to form a frame defining an overall shape of the structure; textile sheets configured to fix over the frame, to define a cavity into which a settable material may be poured; first ties configured to connect between the frame members; and second ties configured to connect between the first ties, wherein the second ties are further configured to connect to the textile sheets, the second ties configured to retain the textile sheets in place during the setting of the settable material.
2. The apparatus of any preceding claim, wherein the frame members each have a cellular construction such that settable material can flow into the cells prior to setting of the settable material.
3. The apparatus of claim 1 or 2, wherein each textile sheet is configured to connect to and span between two frame members at opposing sides of the frame.
4. The apparatus of claim 3, wherein the frame members comprise front left, front right, back left, and back right frame members, and wherein the textile sheets comprise a front textile sheet that is configured to form a front surface of the structure by connecting between the front left and front right frame members, and a back textile sheet that is configured to form a back surface of the structure by connecting between the back left and back right frame members.
5. The apparatus of any preceding claim, wherein the frame members comprise left transverse frame members configured to connect between the front left and the back left frame members, and right transverse frame members configured to connect between the front right and the back right frame members, and wherein a plurality of the first ties are configured to connect between the left transverse frame members and the right transverse frame members.
6. The apparatus of any preceding claim, wherein the first ties comprise two layers of first ties, the two layers being in parallel planes, and wherein the second ties are connected to the first ties and span between the two layers.
7. The apparatus of claim 6, wherein each layer is a grid formed by a first set of first ties and a second set of first ties, the first and second sets of first ties being orthogonal to one another.
8. The apparatus of claim 7, wherein the second ties are connected at crossings between the first ties of the first set and the first ties of the second set.
9. The apparatus of any preceding claim, wherein the second ties are connected to the first ties by looping around the first ties.
10. The apparatus of any preceding claim, wherein the second ties are connected to the textile sheets by looping through hoops of the textile sheets.
11. The apparatus of any preceding claim, wherein the first and second ties are sufficiently flexible that they can be rolled up for transportation.
12. The apparatus of any preceding claim, wherein the first and second ties are steel wire ropes.
13. The apparatus of any preceding claim, wherein the textile sheets are porous to allow passage of water and air through the textile sheets.
14. The apparatus of any preceding claim, wherein the textile sheets are anti-spall sheets to prevent spalling of the settable material.
15. The apparatus of any preceding claim, further comprising the settable material.
16. The apparatus of claim 15, wherein the settable material is concrete. F'
17. A structure formed by and comprising the apparatus of any preceding claim.
18. The structure of claim 17, wherein the structure that is resistant to blast impulses of greater than 2500 kPa-msec and blast pressures of greater than 1000 kPa.
19. The structure of claim 18 or 19, wherein the structure is resistant to blasts in excess of level D5 Bag I Suitcase, 20 kg Explosives, as defined in NATO Standardisation Agreement (STANAG) 2280 -Design Threat Levels and Handover for Temporary Protective Structures (Edition 1, 2008).