GB2078279A - A fall-out shelter or basement structure - Google Patents

Abstract

A structure such as a tank, basement, blast-proof garage or fall-out shelter has a plurality of, precast concrete end wall elements (1B) of L-shape, with the foot of each L-shaped wall element extending inwardly of the structure, precast concrete side wall elements (not shown), and precast concrete roof elements (2C) supported on the end wall elements (1B) and spanning them. The assembly of elements is enclosed in a concrete shell (10) and has a concrete floor (3), the whole being mounted on a foundation (4). The roof elements are preferably double-Tee sections. <IMAGE>

Description

SPECIFICATION A strong structure, for example a fall-out shelter or a basement structure This invention relates to shelters and other structures, a strong structure, for example a fall-out shelter or a basement structure. It is an object of the invention to provide a strong structure of quite large span which is relatively simple in construction and can be rapidly assembled.

According to this invention a strong structure, for example a fall-out shelter or a basement structure, comprises a plurality of upright, precast concrete wall elements and at least one precast concrete roof element supported on the wall elements and spanning the space between the wall elements. The precast concrete elements are preferably encased in, and may also be supported on, a concrete surround which is formed in-situ and which may be tied to the elements by projecting links cast into the elements.

Preferably the concrete wall elements are supported on an in-situ concrete foundation.

According to another aspect of the invention a method of constructing the strong structure comprises the steps of selecting from a stock of standard precast concrete members a plurality of wall and roof elements according to the size and configuration of the structure, placing selected wall elements in an upright position on an in-situ foundation, placing the selected roof element or elements on the upright wall elements, and forming an in-situ shell, of, for example, concrete, around the assembled elements. The structure may be assembled as an underground or above-ground building. Preferably construction includes the step of first forming in-situ concrete foundations and casting a raised, in-situ concrete floor.

The precast wall elements may include L-shaped sections in which the foot of the L forms a base for the wall element, which base extends inwardly of the upright wall portion and abuts the edge of the raised floor. Alternatively, the floor can be formed in-situ between the wall elements after they have been placed in the required position on the foundations.

The top edges of the wail elements, preferably the end wall elements of the structure, may be contoured to match the shape of the roof elements, when the latter are, for example, ribbed on their surfaces.

Some of the applications of the invention are: (a) as a basement structure; (b) as a community shelter for use by local authorities, or in factories or similar areas where a relatively large protected space is required for sheltering a large number of people; (c) as a command or communications centre, or as an underground hospital, where, again, a relatively large covered space is required; (d) as a blast-proof garage for ambulances, fire or police vehicles or other emergency vehicles; and (e) as a static water tank having overhead protection against radio-active or other contamination.

The invention will now be described by way of example with reference to the drawings, in which Figure 1 is a side elevation of a shelter or other structure including an in-situ concrete casing, one side of which has been omitted from the figure to reveal the arrangement of the precast elements; Figure 2 is an end elevation of the structure of Figure 1 with part of the concrete casing omitted; Figure 3 is a plan of the structure of Figure 1 with the whole of the concrete casing omitted, and drawn to a larger scale; Figure 4 is a partial section on the plane B-B of Figure 3; and Figure 5 is a partial section on the plane A-A of Figure 3, showing the construction of one end of the structure.

Referring to the drawings, a strong structure, in this case a shelter, has four L-shaped end wall elements arranged in pairs of opposed elements 1A, 1 B and 2A, 2B. These elements are identical precast concrete sections and are placed with their foot portions facing inwardly and abutting the end faces of a raised concrete floor slab 3 which is cast in-situ on a concrete foundation 4. The end wall elements 1A, 1 B, 2A and 2B support two roof slabs 1C and 2C each of double-T section, with the stem parts 5 (see Figure 2) of the roof slabs housed in correspondingly shaped slots 6 cast into the upright parts of the end wall elements. Flat or ribbed side wall slabs 7 and 8 rest against the side edges of the floor slab, the roof slabs and the end wall elements.The side wall slabs 7 and 8, and the end wall elements 1 a, 1 B, 2A and 2B may be pulled together by horizontal tie rods (not shown) passing horizontally between adjacent elements with the rods located within the elements or outside them. The side wall slabs 7 and 8 may be tied by vertical bolts 9 to the concrete foundation 4 to give greater strength in the structure as a whole. The links between the precast elements may also include long bolts either outside the elements or running in channels within them so as to provide elastic connections which allow some relative movement of the elements for greater resistance to, for example, horizontal seismic forces. These bolts may extend the full width of each concrete element.

The precast elements described above are selected from a range of elements of three basic shapes which may be fitted together to create a structure of the required size. The drawings show a shelter structure of a width corresponding to the width of the two double roof slabs 1 C, 2C and the two pairs of wall elements 1A, 1 B and 2A, 2B. A structure of greater width could be built by increasing the number of roof slabs and wall elements.

Likewise the length of the structure could be increased by selecting roof slabs and side wall slabs of greater length. Using this modular system of construction, a range of standard elements can be assembled in different configurations to produce structures of different sizes and specifications.

Once the precast elements have been assembled on site, a concrete shell 10 is cast around the assembly to provide extra strength and to seal gaps between the elements. Shear links 11, embedded in the precast elements, project vertically from the roof slabs, horizontally from the L-wall elements, and horizontally from the side walls to provide a key for the in-situ concrete shell 10. Holes may be made through the rib ends on the roof slabs for dowel pins (not shown). These features provide extra resistance to seismic or blast damage. Reinforcement of the floor slab 3 and the concrete foundation 4 is also desirable (see reference 12 in Figures 4 and 5).The gaps in the floor of the structure between the foot portions 13 of the L-wall elements are preferably infilled with in-situ concrete which is tied to the concrete beneath and also preferably to the foot portions 13 by projecting reinforcement links.

Greater strength may be obtained by using L-wall elements not only for the end walls of the structure, but also for the side walls.

Openings may be precast or cut in any of the wall or roof elements to accommodate doors and services.

In addition to providing a method whereby structures of different sizes can be produced from a range of standard precast components, the modular system of construction enables an underground structure to be rapidly constructed, and in particuiar can provide a-basement structure which will withstand the weight of a building above. The structure is also readily sealed by known means to provide a roofed water tank protecting the water from contamination by debris, fall-out, or chemical or biological agents.

Claims (10)

1. A strong structure, for example a fall-out shelter or a basement structure, comprising a plurality of upright, precast concrete wall elements and at least one precast concrete roof element supported on the wall elements and spanning the space between them.

2. A structure according to claim 1, wherein a wall element includes an L-shaped section whose foot forms a base for the wall element, which base extends inwardly of the upright portion of the wall element.

3. A structure according to claim 2 having a concrete floor against an edge of which the base abuts.

4. A structure according to any preceding claim wherein the or each roof element is of inverted double-Tee shape, wall elements being recessed to receive and locate ribs of the or each roof element.

5. A structure according to any preceding claim having a concrete shell cast around the assembly of elements, the elements having projecting links by which the concrete shell is keyed.

6. A method of constructing a strong structure, for example, a fall-out shelter or a basement struc ture, comprises the steps of selecting from a stock-of standard precast concrete members a plurality of wall and roof elements according to the size and configuration of the structure; placing the selected wall elements in an upright position on a foundation; placing the selected roof element or elements on the upright wall elements; and forming a shell of material around the assembled wall and roof elements.

7. A method according to claim- 6 which the said material is concrete.

8. A method according to claim 6 or claim 7 comprising the initial step of first forming an in-situ concrete foundation and casting in a raised, in-situ concrete floor.

9. A strong structure constructed and arranged substantially as herein described and shown in the drawings.

10. A method of constructing a strong structure, the method being substantially as herein described with reference to the drawings.