GB2139277A

GB2139277A - Connector sockets in cast concrete elements

Info

Publication number: GB2139277A
Application number: GB08312295A
Authority: GB
Inventors: Samuel Bailey Hart Mitchell
Original assignee: Charcon Tunnels Ltd
Current assignee: Charcon Tunnels Ltd
Priority date: 1983-05-05
Filing date: 1983-05-05
Publication date: 1984-11-07
Also published as: GB8312295D0; GB2139277B

Abstract

The disclosure relates to an arcuate cast concrete tunnel lining segment (10) having sockets (12) cast in one circumferential edge (11) thereof. Each socket has a cross-section to receive a head (23a) on a connector bolt. The socket has a shoulder (15) which provides a cavity (16) to receive the end of the head (23a) of the connector element when turned 90 DEG into engagement beneath the shoulder. <IMAGE>

Description

SPECIFICATION Improvements in or relating to cast con crete elements This invention relates to cast concrete ele ments having attachment sockets cast therein for lifting of the elements and/or attachment to other elements.

The invention provides a cast concrete ele ment having a connector socket cast into the element adjacent a surface thereof to receive a connector having an elongate head, the socket, adjacent the surface of the element, having an elongate transverse cross-section to receive the elongate head of the connector with the head aligned in the elongate direction of the socket, and a cavity on at least one elongate side of the socket spaced into the body from the surface of the element into which the elongate head of the connector may be turned, the cavity providing a shoulder facing away from the surface against which a part of the head can be engaged to hold the connector in the socket for lifting of the element.

The following is a description of one specific embodiment of the invention, reference being made to the accompanying drawings in which: Figure 1 is a perspective view of an arcuate concrete segment for a tunnel or shaft lining having two spaced sockets in one circumferential edge for receiving hoists connectors for attachment of the segment to further segments; Figure 2 is a perspective view of one of the sockets; Figure 3 is a side view of a socket; Figure 4 is an end view of the socket; Figure 5 is a plan view of the socket; Figure 6 is a similar view to Fig. 1 showing the ropes of a hoist with connector elements attached engaged in the sockets of the segment; and Figures 7 to 12 and 13 to 15 illustrate two further forms of socket.

Referring firstly to Fig. 1 of the drawings there is shown an arcuate pre-cast concrete segment 10 for a tunnel lining which is shown with its axis extending vertically and with a circumferentially extending edge face 11 uppermost. Two sockets indicated generally at 1 2 are cast into the segment adjacent the face 11 at positions disposed symmetrically around the face from the centre line of the segment, each socket having a rectangular open mouth 1 3 at the surface of the segment.

The axially extending edges Sa, Sb of the segment 10 are connected by the overlapping hoop and expanded tapered pin joint construction described and iilustrated in our U.K.

Patent No. 2,004,931 and U.K. Patent Application No. 8235005. The sockets 12 in the circumferentially extending edge 11 will now be described in greater detail with reference to Figs. 2 to 5.

The socket 1 2 comprises a hollow elongate rectangular section plastics moulding having side walls 14 and end walls 14a. The socket has an open end 1 3 which, in situ lies flush with the edge face 11 of the segment. The socket is intended to receive a T-shaped head of a connector element which will be described in greater detail later. The internal length and width of the socket are slightly greater than the corresponding length and width of the T-shaped head respectively so that the head can be slid into the socket with the T-shaped head extending lengthwise of the socket.

Partway along the socket from the mouth 1 3 the side walls 1 2 are stepped outwardly by arcuate shoulders 1 5 extending across the sides 1 2 to form cavities 16 on either side of the sockets into which the ends of the Tshaped head on the connector element may be turned. The shoulders 1 5 within the socket form concavely curved seats 1 7 against which the ends of the T-shaped head can bear to retain the connector in the socket and two integral spring detents 18 are formed at spaced locations around each curved seat 18 to snap around and hold the ends of the Tshaped head against the seats 1 7.

The outer sides of the shoulders 1 5 are formed with grooves 1 9 and U-shaped reinforcing bars 20 are located on either side of the socket with the base of each bar located in the respective grooves 1 9 and the legs extending away from the socket. The ends faces 1 5 of the socket are formed with Lshaped detents 21 adjacent the ends of the arcuate grooves 1 9 which are snapped over the reinforcing bars to hold them in place.

The free ends of the bars 20 may be turned outwardly as indicated at 22 to anchor into the concrete of the segment. The bars assist in taking the load imposed on the shoulder 1 5 by the head of the connector when a load is applied to the latter. The bottom of the socket 1 2 is closed by an end cap (not shown) to prevent the ingress of concrete into the socket during the casting of the segment.

Fig. 6 of the drawings is a similar view to Fig. 1 showing two connector elements 23 connected to the wire sling 24 of a hoist. The connector elements have T-shaped heads indicated at 25 which are inserted in the sockets 1 2 in the segment end and turned to engage the ends of the heads on the concave seat 1 7 in the cavity 16. With the connectors thus locked in position, the segment can be raised using the hoist. It will be noted that the length of the elongate sockets is such that the length connector elements can take up inclined positions to align with the inclined stretches of the sling 24. Reference should be made to our U.K. Patent Application No.

(Reference: GCB/BA4760) for a more de tailed description of the connector 23.

The socket can also be used for connecting adjacent segments together using connector bars having T-shaped heads at one end and screw-threaded at the other end to receive nuts. Reference should be made to our U.K.

Patent Specification No. (Reference: GCB/BA4622) for a more detailed description.

It will be appreciated that many modifications may be made to the above described embodiment without departing from the scope of the invention. For example the socket 1 2 may be cast into the segment below the face 11 with a straight or tapered opening formed in the face of the segment leading into the open mouth 1 3 of each socket. Further, the sockets 1 2 may have cavities 1 6 on one side only thereof for engagement by an L-shaped headed connector element and Figs. 7 to 12 and 1 3 to 1 5 illustrate two versions of such a socket. The further sockets are generally similar to socket 1 2 described above and the like parts have been allotted the same reference numerals.One end wall 1 4a of the socket is curved to receive the end of an L-shaped end 23a of connector 23 and the socket has only a single cavity 16 formed part-way down one side wall 14 of the socket and providing a shoulder 1 5 forming a flat seat 1 7 on the inside of the cavity to receive the end of the Lshaped connector element when the latter is turned in the cavity. A bridge 30 is formed integrally between the outer side of the shoulder 1 5 and the adjacent side 14 of the socket to provide an aperture 31 to receive and hold a reinforcement member 32 cast in the concrete segment to bear against the outer side of the shoulder 1 5 and withstand the load imposed on the shoulder by the L-shaped connector element 23a. The open end 1 3 of the socket is formed with a bell-mouth entry 1 3a to assist in guiding the L-shaped connector element into the socket.

Figs. 10 to 1 2 show a similar arrangement but with the walls of the socket extending beyond the bell-shaped entry to provide a longer socket extending more deeply into the segment and which may be utilised without the support of a reinforcement member.

Claims

1. A cast concrete element having a connector socket cast into the element adjacent a surface thereof, to receive a connector having an elongate head, the socket adjacent the surface of the element having an elongate transverse cross-section to receive the elongate head of the connector with the head aligned in the elongate direction of the socket, and a cavity on at least one elongate side of the socket spaced into the body from the surface of the element into which the elongate head of the connector may be turned, the cavity providing a shoulder facing away from the surface against which a part of the head can be engaged to hold the connector in the socket for lifting of the element.

2. A cast concrete element as claimed in claim 1 wherein the socket has cavities on both sides thereof to receive parts of a head of the connector projecting on either side of the connector.

3. A cast concrete element as claimed in claim 1 wherein the socket has a cavity on one side only thereof to receive a part of a head of a connector projecting on one side only of the connector.

4. A cast concrete element as claimed in any of claims 1 to 3 wherein the or each cavity has detent means to hold releasably the headed part of the connector located in the cavity.

5. A cast concrete element as claimed in claim 4 wherein the detent means in the or each cavity comprise a spaced pair of spring arms projecting from the shoulder in the cavity to embrace the headed part of the connector element to be engaged in the cavity.

6. A cast concrete element as claimed in any of the preceding claims wherein the or each cavity in the socket is formed by an outwardly extending step in the side of the socket, the inner side of the step providing said shoulder in the cavity facing away from the surface of the element and reinforcing means being provided in the element around the outer side of the stop to assist in bearing the load imposed on the step by the head of the connector.

7. A cast concrete element as claimed in claim 6 wherein for the or each cavity in the socket there is a U-shaped reinforcing bar cast in the element, the base of the bar expending over the outer side of the step in the elongate side of the socket.

8. A cast concrete element as claimed in claim 7 wherein a groove is formed in the outer side of the step to receive the base of the U-shaped reinforcing bar.

9. A cast concrete element as claimed in claim 6 or claim 7 wherein detent means are provided on the outer side of the socket to hold the reinforcing bar or bars on the socket.

10. A cast concrete element in the form of an arcuate segment for a shaft or tunnel lining having on one circumferentially extending edge face two sockets cast therein geometrically about the centre line of the segment for lifting and/or connection to further segments.

11. A cast concrete element substantially as described with reference to and as illustrated in the accompanying drawings.