Improvements in or relating to joining concrete elements

Abstract: The disclosure relates to a concrete element (10) having a corner (14) between a side face (12) and an end face (11) in which a box shaped cavity (15) is formed. A pair of U-shaped loops (18) is cast in the segment at the corner with base members (19) of the loops extending parallel to one another across the cavity to receive a fixing bolt (12) which has a head (21) and washer brackets (22) engaging behind the loops and a shank extending from the end of the element to engage in a nut similarly held in a recess of a corresponding segment for securing the segment ends together. The arrangement permits the bolt to be tightened through the cavities at the sides of the segments. The arrangement is particularly suitable for securing arcuate concrete tunnel lining segments together.

Description: This invention relates to concrete elements as is particularly although not exclusively applicable to concrete elements in the form of precast arcuate concrete tunnel or shaft lining segments. GB-A-2,092,644 discloses arcuate concrete segments of a tunnel lining joined together by means of a recess in a segment edge having a pair of abutment members projecting into the recess to define a constriction therein, the abutment member forming a pair of abutment surfaces facing inwardly of the constriction and a screw threaded headed bolt in an adjacent segment. The segments are positioned edge to edge with the bolt inserted in the recess and moved relatively to each other so that the bolt head engages the abutment surfaces. The recess is accessible from the inner arcuate surface of the lining to allow the bolt to be tightened. The object of this invention is to provide a joint between arcuate concrete segments at the tunnel lining in which there is no recess or cavity opening into the inner surfaces of the segments. This invention provides an arcuate concrete tunnel lining segment having a corner between a pair of mutually angled faces including an axially extending end face with respect to the tunnel axis adapted for connection to an adjacent axially extending end face of another segment, the corner having an anchorage cast into the segment at or adjacent of said end face of said corner with a cavity formed behind the anchorage which is open to the other of said mutually angled faces of the corner to enable an attachment member to be located in the cavity in engagement with the anchorage and to project from said end face and engage with the other segment to secure the segments together; wherein said mutually angled faces comprising the axially extending end faces and circumferentially extending side faces of the segment with respect to the longidutinal axis fo the tunnel, the cavities being open to the side faces to enable the access to the atachment members in order to maintain uninterrupted, the complete inner arcuate faces of the connected lining segments. In one arrangement according to the invention, the anchorage may provide an opening through which the attachment member extends, the attachment member having abutment means to engage behind the anchorage to retain the attachment member in the anchorage. More specifically, the anchorage may comprise a plurality of bars cast into the concrete element and spaced apart to permit the attachment member to extend between the bars with the abutment means of the attachment member engaged behind the bars. For example, the bars may comprise a pair of parallel bars cast into the concrete element. More particularly, a pair of rigid U-shaped elements may be cast into the segment with the bases of the elements projecting onto the cavity to provide the bars with which the attachment member engages Reinforcing members may be cast in the element and said bars are connected to the reinforcing members. In any of the above arrangements, the attachment member may comprise a threaded bolt adapted to engage in a threaded socket in the corner of the adjacent segment. Thus, each end face of the segment may have a cavity at one corner from which a bolt projects and has a threaded socket in the other corner to make a joint with a similarly provided segment end. In a further construction, the anchorage may comprise an apertured plate cast into the concrete segment at or adjacent said one edge face. For example, the segment may contain reinforcing members cast into the segment and to which the anchorage plate is connected. The following is a description of some specific embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is a side view of a joint between two arcuate concrete tunnel lining segments; Figure 2 is a view on the section A-A on Figure 1; Figure 3 is a perspective view of a corner of one of the segments of Figure 1; Figures 4 and 5 are similar views to Figures 1 and 2 showing a modified construction; Figures 6 and 7 are also similar views to Figures 1 and 2 showing a further modified construction; and Figures 8 and 9 are also similar views to Figures 1 and 2 showing a still further modified construction. Referring firstly to Figures 1 to 3 of the drawings, there is shown parts of two pre-cast concrete arcuate tunnel lining segments 10 having axially extending end faces 11 and circumferentially extending side faces 12. The segments are secured together at their axially extending edge faces with a gasket 13 between the adjacent faces by means of corner connections which will now be described with particular reference to Figure 3. Figure 3 of the drawing shows one corner indicated generally at 14 of one of the segments 10 between a side face 12 and an end face 11. At a mid-position within the thickness of the segment, the corner is formed with a box shaped cavity 15 which extends across the corner and is open at 16 to the side face 12 and at 17 to the end face 11. A pair of flat bottomed U-shaped loops 18 are cast into the segment at the corner with the base members 19 of the loops extending parallel to one another and adjacent to the end face 17. The base members extend parallel to one another across the cavity 15 as shown in Figure 3 and the arms of the U-shaped members extend into the thickness of the segment as illustrated in Figure 1 and made be tied into main reinforcement bars (not shown) of the segment. A fixing bolt 20 extends through the exposed parts of the loops 19 and is held captive by a head 21 and washer 22 on the bolt engaging behind the loops within the cavity 15. The cavity 15 extends sufficiently behind the loops 19 to enable the bolt 20 to be inserted through the loops from the opening 16 in the side face of the segment into the cavity. The corresponding corner of the adjacent segment has a similar cavity and loop arrangement and the fixing bolt 20 extends through the loops 19 of the further corner to receive a washer 23 and nut 24 for securing the end faces of the segments together. A similar connection is provide between the corner joints at the opposite ends of the end faces 17 so that the end faces of the segments can be secured together adjacent both ends thereof. In erecting a ring of segments in a tunnel or shaft, two segments are located with their axially extending faces in abutment and with the segments spaced from the previously erected ring of segments. The end faces of the segments can then be secured together as described above and once a complete ring of segments has been secured together in a similar manner, the ring is then moved into engagement with and secured to the previously erected ring. The segments of one ring may for example, be connected to the segments of the previously erected ring using any of the arrangements disclosed in our U.K. Patent Specification Nos. 2003212, 2139277, 2139268, 2139278 or 2133852. A further ring of segments is then erected and secured together as before. A throughway 25 is provided between each cavity 15 and the outer circumferential surface of each segment so that when the lining has be fully erected and grout is delivered under pressure to fill the cavity between the outer surface of the lining and the excavated tunnel, the grout will be driven into the cavities 15 through the throughways to fill and seal the cavities. Thus the connecting elements including the bolts and bars are protected against corrosion. Figures 4 and 5 show a similar arrangement to that of Figures 1 and 2 and like parts have been allotted the same reference numerals. The main difference is that the loops 18 are cast in the segments 10 with the base parts 19 of the loop set back from the respective end faces 11 thus there is a wall concrete 26 between each cavity 15 and the end face 11 which is formed with a bore 27 through which the bolt 20 extends. The arrangement is otherwise similar to that described above. Figures 6 and 7 show a further variation on the arrangement of Figures 1 and 2 in which the corner one of the segments 10 is formed as described with respect to Figures 1 and 2 and the adjacent corner of the other segment 10a has a threaded cast-in socket 28 extending into the segment from the end face 11 to receive the bolt 20 projecting from said one segment. The cast in socket 28 is attached to the reinforcement 29 of said other segment. As can be seen in Figure 7, the joints at opposite ends of the segments are handed so that each segment has a bolt projecting from one corner and a socket at the other corner for engagement with a corresponding socket and bolt respectively of an adjacent segment. The arrangement shown in Figures 8 and 9 is also similar to that of Figures 1 and 2 except that the loops 18/19 are replaced by apertured plates 30 cast into the end faces of the segments to which loops 31 are connected which extends into the respective segments and may be connected to main reinforcement bars. The arrangement is otherwise similar to that described above.

Claims: An arcuate concrete tunnel lining segment (10) having a corner between a pair of mutually angled faces including an axially extending end face (11) with respect to the tunnel axis adapted for connection to an adjacent axially extending end face (11) of another segment (10), the corner having an anchorage (18,19) cast into the segment (10) at or adjacent of said end face (11) of said corner with a cavity (15) formed behind the anchorage (18, 19) which is open to the other of said mutually angled faces of the corner to enable an attachment member (20-24) to be located in the cavity (15) in engagement with the anchorage (18,19) and to project from said end face (11) and engage with the other segment (10) to secure the segments (10) together; characterised in that said mutually angled faces comprising the axially extending end faces (11) and circumferentially extending side faces (12) of the segment (10) with respect to the longidutinal axis fo the tunnel, the cavities (15) being open to the side faces (12) to enable the access to the atachment members (20-24) in order to maintain uninterrupted, the complete inner arcuate faces of the connected lining segments (10). An arcuate concrete segment as claimed in Claim 1, characterised in that the anchorage (18,19) provides an opening through which the attachment member (20,21) extends, the attachment member having abutment means (21) to engage behind the anchorage to retain the attachment member in the anchorage. An arcuate concrete segment as claimed in Claim 2, characterised in that the anchorage comprises a plurality of bars (18,19) cast into the concrete element and spaced apart to permit the attachment member (20) to extend between the bars with the abutment means (21) of the attachment member engaged behind the bars. An arcuate concrete segment as claimed in Claim 3, characterised in that the bars comprise a pair of parallel bars (19) cast into the concrete element. An arcuate concrete segment as claimed in Claim 3 or Claim 4, characterised in that a pair of rigid U-shaped elements (18) is cast into the segment with the bases (19) of the elements projecting onto the cavity (15) to provide the bars with which the attachment member engages An arcuate concrete segment as claimed in any of Claims 3 to 5, characterised in that reinforcing members are cast in the element and said bars (18) are connected to the reinforcing members. An arcuate concrete segment as claimed in any of the preceding claims, characterised in that the attachment member comprises a threaded bolt (20) adapted to engage in a threaded socket (28) in the corner of the adjacent segment. An arcuate concrete segment as claimed in Claim 7, characterised in that each end face of the segment has a cavity (15) at one corner from which a bolt projects and has a threaded socket in the other corner to make a joint with a similarly provided segment end. An arcuate concrete segment as claimed in Claim 1, characterised in that the anchorage comprises an apertured plate (30,31) cast into the concrete segment (10) at or adjacent said one edge face (11). An arcuate concrete segment as claimed in Claim 9, characterised in that the segment (10) contains reinforcing members cast into the segment and to which the anchorage plate (30,31) is connected.

Inventors: MITCHELL SAMUEL BAILEY HART, MITCHELL, SAMUEL BAILEY HART
Applicants: CHARCON TUNNELS LTD, CHARCON TUNNELS LIMITED
Application year: 1989
Main classification: E21D11
IPC codes: E21D11