GB2284000A

GB2284000A - Blast-absorbing mounting for building component

Info

Publication number: GB2284000A
Application number: GB9423385A
Authority: GB
Inventors: Anthony Wilson
Original assignee: GLOSTAL Ltd
Current assignee: GLOSTAL Ltd
Priority date: 1993-11-20
Filing date: 1994-11-19
Publication date: 1995-05-24
Anticipated expiration: 2014-11-19
Also published as: GB2284000B; GB9323924D0; GB9423385D0

Abstract

A blast absorbing mounting device for resiliently mounting a building component such as a glazing, cladding or roofing panel to a building which comprises a first plate member (1) which may be attached to a building structure by means of a bolt (6), a second plate member (3) which may be attached to the frame (7) of a glazed or other panel, the first and second plate members being joined together by means of a resilient membrane (2) of elastomeric material bonded to the mutually facing surfaces of the plates (1) and (3) whereby the force of a blast suffered by the panel may be damped or attenuated by the resilience of the mounting. <IMAGE>

Description

Blast Absorbing Mounting Device This invention relates to a blast absorbing mounting device for resiliently mounting a building component such as a window or a panel or other element or assembly which, in use, may be exposed to the shock wave caused by an explosion of some kind, the mounting device having incorporated therein a resilient component to absorb the resultant shock loading and which can also accommodate normal structural movements and loads, to which the component may be subjected.

In this specification, the term 'building component' includes, without limitation, windows and doors, frames, panels, claddings; decking and roofing panels for buildings and other structures of any sort which may be exposed to, or which may be vulnerable to any kind of explosive event, and the term 'building' is to be understood and construed accordingly.

Intense, suddenly applied dynamic loads of short duration and of appreciable magnitude as are produced by an explosion, may result in an actual stress in excess of the original design specification for the building. Under these conditions, when a building component is held by an unyielding mounting, which has been the practice hitherto, plastic strain deformation of the component may occur, resulting in the premature failure of the building component.

Under such conditions, no elastic recovery may be possible and the building component such as a window may not be capable of providing protection against the effects of a second or subsequent blast and it may well not even provide sufficient protection from the primary explosion. Under shock load design it is possible to increase the maximum allowable stress levels further but mechanical reinforcement adds to the weight and cost of the building component. If in accordance with this invention the building component is mounted so as to absorb energy, a less substantial component is required which has economic advantages. By means of this invention, a given degree of protection may be obtained by the use of a building component which is lighter and less expensive than would be the case otherwise.

In one aspect, this invention comprises a blast absorbing mounting device for resiliently mounting a building component to a building comprising: a first mounting member which may be fixed to the building, means for attaching the building component to the said first mounting member so that the building component is relatively moveable with respect to the first mounting member and means being so disposed and arranged to resiliently resist a displacement of the building component whereby in the event of an impulsive force being applied to an exposed surface of the building component the displacement is resisted by a resilient force to attenuate the blast.

Preferably, a second mounting member is provided for attachment to the building component and the said first and second mounting members are joined together by a resilient member whereby a relative displacement of the first member with respect to the second member produces the resilient force which resists the relative displacement of the two members.

The resilient member may be a synthetic elastomeric material which is firmly attached to each of the said first and second mounting members. The use of elastomeric materials is particularly advantageous since a variety of membranes having predetermined properties as may be required can readily be produced and such material is capable of strong bonding to the mounting members thus facilitating the construction of economic blast absorbent mountings.

The elastomeric material is preferably bonded to each of the mutually facing surfaces of the said first and second mounting members.

One end portion of the mounting device may be adapted to be located between an edge of the building component and the building to which it is mounted, the device, in use, extending away from the building component, the first mounting member being adapted to be attached to the building, the second mounting member being adapted for attachment to an edge portion of the building component.

The first mounting member may be provided with an aperture which underlies the second mounting member, the aperture being adapted to freely receive the head of fixing means for fixing the second mounting member to the edge portion of the building component ,the aperture being so dimensioned as to prevent the head of the fixing means from contacting the first mounting means under conditions when the mounting members may move relative to each other in consequence of an explosion.

In a further aspect of the invention the first mounting member may be in the form of an elongate channel member which may be attached to a building and the second mounting member is in the form of a elongate frame element which is adapted to retain the edge portions of a building component in the form of a panel The elongate frame element is preferably in the form of a hollow extruded mullion bar which is disposed partly within the channel member and a resilient member joins each of the opposing sides of the mullion bar to the adjacent wall of the channel member.

Retaining means may be provided to support the mullion bar within the channel member which means are preferably in the form of a bolt or bar which passes through the mullion bar and through an elongated hole formed in each wall of the channel member so as to permit the relative resilient movement of the mullion bar with respect to the channel member under the influence of applied impulsive loads.

In a further aspect this invention consists in a blast absorbing building component assembly or a kit of parts for the installation of such an assembly comprising a building component, a plurality of devices as claimed in any claim 1 to 6 for attachment around the periphery of the building component whereby the building component may be resiliently mounted to a building structure whereby in use the resilience of the mounting at least partly absorbs the impulsive loads caused by an explosion.

In a yet further aspect, this invention consists in a blast absorbing curtain walling assembly or a kit of parts suitable for the installation of such an assembly comprising a plurality of devices as claimed in any claim 7 to 10 for attachment to a building whereby a plurality of glazing or other panels may be resiliently mounted between adjacent devices so as to absorb an applied impulsive load The invention will be more particularly described by way of example only with reference to the accompanying drawings in which: Figure 1 is a cross-sectional drawing illustrating one embodiment of a blast absorbing mounting device which is shown in situ located in a window opening Figure 2 illustrates, top and bottom views of the embodiment shown in Figure 1 Figure 3 is a cross sectional drawing of a second embodiment of a blast absorbent mounting device suitable for a curtain wall or other wall or roof cladding systems.

Referring to the drawings, Figure 1 shows the application of the invention to a window system in a building structure. The building may be of any construction, such as a being provided with a concrete or steel frame or it may be of a hardened design. A shock load as may be caused by an explosion, may arrive at the surface of the window (only the edge of which is shown) in the direction of arrow A. Under extreme conditions the load may reverse becoming a suction or negative load or an oscillating load, in which the direction of the load rapidly oscillates. The devices according to this invention are adapted to absorb positive, negative or oscillating loads exerted on an exposed surface of a building component which are mounted by means of such devices.. Building components such as glazed windows, cladding or roofing panels may all be mounted so as to absorb shock loads. The window frame as illustrated in part in Figure 1 is reinforced against bending moments by means suitable reinforcement in the form of a shear plate 5 which may be inserted into the horizontal and vertical portions of the glazing frame.

The blast absorbing mounting device consists of a load plate 1, constituting a first mounting member, a plate 3, constituting a second mounting member, the plate 3 being adapted to be attached to the edge of the glazing unit frame 7, and a resilient member in the form of an elastomeric membrane 2 which is bonded to each of the mutually facing surfaces of the plates 1 and 3.

The load plate 1 has provision for attachment to the main building structure by means of a fixing 6 which passes through an aperture located towards one end portion of the plate 1.

The elastomeric material is a known structural silicone, an elastic material which absorbs strain energy at the same time as providing substantial displacement capacity. The residual load B transmitted to the building structure is effectively damped thereby reducing the need for a building structure design to accommodate excessive imposed or unquantified shock loading.

A suitable structural silicone material is commercially available under the trade name Dow Corning 983 Two Part Structural Silicone. The surfaces of the plates 1 and 3 must be pretreated by known means to provide surfaces which will adequately bond to the structural silicone material. The assembly of plates 1 and 3, as shown in Figures 1 and 2 was made by positively holding the plates 1 and 2 in parallel, at a distance 6 mm apart, the structural silicone material being injected under pressure into the cavity defined by the common area between the two plates, the common area being not smaller than 3800 mm2 for a 6 mm thick membrane of the selected structural silicone material.

A stress parameter indicator in the form of a shear pin 4, may be fitted to a number of devices attached to a building so as to indicate visually the effect of impulsive loads, without the need for detailed structural analysis. In the case of the embodiment illustrated and described with reference to Figures 1 and 2, the stress parameter indicator 4 was located on plate 1 at a distance of 12 mm behind the innermost edge of the residual load plate 3, to provide an indication as to whether a predetermined positive stress level has been exceeded. As shown in Figure 1, one end portion of the blast absorbing device is secured to the building structure by means of fixing 6 the opposite end portion being disposed between the building structure and the frame 7 of the glazing unit. The plate 3 is adapted to be attached to the frame 7 by the provision of a hole 3a for the receipt of a bolt which secures plate 3 to frame 7. As may be more clearly seen from Figure 2, the inner end portion of plate 1 has an elongate slot la to permit the head of the bolt fixing means to seat against the underside of plate 3, the bolt passing through hole 3a. The slot la is so dimensioned to ensure the plates 1 and 3 remain free for relative movement under the influence of applied shock loads.

Referring to the second embodiment illustrated in Figure 3, a mullion bar constituting an elongate fame element 1 supports curtain-walling panels 2 (only the edge portions of which being shown) on the external side of a building which is indicated by numeral 7. The inner end portion of the mullion bar, which is in the form of a hollow extrusion of aluminium alloy, is positioned within the opening of a U shaped channel element 3, constituting an elongate channel member, to which it is firmly bonded on each of the opposed sides to the adjacent walls of the channel element 3, by means of the structural silicone membrane 6 of the material referred to in relation to the embodiment described with reference to Figures 1 and 2.

The mullion bar 1 is mechanically retained within the U shaped channel element 3 by means of bolt 4 which passes through slotted holes 5 in the limbs of the channel element 3.

Bolt 4 supports the weight of the curtain wall assembly but under shock load conditions applied to the exterior of the structure, the mullion bar may move further into or further out of the U shaped channel element by virtue of bolt 4 being located in elongate holes 5, which are shown only in dotted outline in Figure 3. As in the case of the embodiment described with reference to Figures 1 and 2, an elastic shear force develops in the membranes 6 which damp or attenuate the shock load applied to the exposed panel surfaces.

The mullion bar 1 and U shaped channel element 3 are mounted on the building structure 7 by means of an adjustable bracket arrangement 8 which supports the channel element 3 by means of the bolt 9. A plurality of assemblies as described with reference to Figure 3 are required in curtain wall applications.

Claims

What we claim is:

1. A blast absorbing mounting device for resiliently mounting a building component to a building comprising: -a first mounting member which may be fixed to the building and means for attaching the building component to the said first mounting member so that the building component is relatively moveable with respect to the first mounting member and means being so disposed and arranged to resiliently resist a displacement of the building component whereby in the event of an impulsive force being applied to an exposed surface of the building component the displacement is resisted by a resilient force to attenuate the blast.

2. A device as claimed in claim 1 in which a second mounting member is provided for attachment to a building component and the said first and second mounting members are joined together by a resilient member whereby a relative displacement of the first member with respect to the second member produces the resilient force which resists the relative displacement of the two members.

3 A device as claimed in claim 2 in which the resilient member is in the form of an elastomeric material which is firmly attached between each of the said first and second members.

4. A device as claimed in claim 3 in which the elastomeric material is bonded to each of the mutually facing surfaces of the said first and second mounting members.

5. A device as claimed in claim 3 or 4 in which one end portion of the device is adapted to be located between an edge of the building component and the building to which it is mounted, the first mounting member in use extending away from the building component the extending portion being adapted to be attached to the building, the second mounting member being adapted for attachment to an edge portion of the building component.

6. A device as claimed in claim 5 in which the first mounting member is provided with an aperture which underlies the second mounting member the aperture being adapted to freely receive the head of fixing means for fixing the second mounting member to an edge portion of the building component the aperture being so dimensioned as to preclude the head of the fixing means from contacting the first mounting means under conditions when the mounting members may move relative to each other.

7. A device substantially as described with reference to Figures 1 and 2 of the accompanying drawings.

8 A device as claimed in any claim 1 to 4 in which the first mounting member is in the form of an elongate channel member which may be adjustably attached to a building and the second mounting member is in the form of a elongate frame element which is adapted to retain the edge portions of a building component in the form of a panel

9. A device as claimed in claim 8 in which the elongate frame element is a hollow extruded mullion bar which is disposed partly within the channel member and a resilient member joins each of the opposing sides of the mullion bar to the adjacent wall of the channel member.

10. A device as claimed in claim 8 or 9 in which retaining means are provided to support the mullion bar within the channel member.

11. A device as claimed in claim 10 in which the retaining means is a bolt or bar which passes through the mullion bar and through an elongated hole formed in each wall of the channel member so as to permit the relative resilient movement of the mullion bar with respect to the channel member under the influence of applied loads.

12. A device substantially as described with reference to Figure 3 of the accompanying drawings.

13. A blast absorbing window or panel assembly or a kit of parts for the installation of such an assembly comprising a glazing or other panel, a frame surrounding the glazing or other panel and a plurality of devices as claimed in any claim 1 to 6 for attachment around the periphery of the frame whereby the window may be resiliently mounted in a window opening so as to absorb an applied impulsive load.

14. A blast absorbing curtain walling assembly or a kit of parts suitable for the installation of such an assembly comprising a plurality of devices as claimed in any claim 7 to 10 for attachment to a building whereby a plurality of glazing or other panels may be resiliently mounted between adjacent devices so as to absorb an applied impulsive load.