JPS644005B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention contributes to the rigidity and toughness of vertical joints in the construction of continuous underground walls without pouring concrete after inserting reinforcing bar cages into trenches excavated deep underground. The present invention relates to a method for arranging shear reinforcing bars.

In order to make the joint of the underground wall a rigid joint, after concrete is poured for the preceding underground wall, the side of the joint that penetrates the box of the vertical joint at the end and protrudes into the inside of the concrete is usually installed. Overlay the reinforcing bars (joint main bars) with the joint main bars of the trailing underground wall reinforcing bar basket, and pour concrete at the joint to integrate them. At this time, since the reinforcing bar cage is suspended vertically (see the open arrow in FIG. 5), the joint main bars of the leading wall and the trailing wall are shifted from each other on the plane to form a lap joint. For this reason, in the past, transverse reinforcing bars or shear reinforcing bars in the direction perpendicular to the underground wall were attached to the inner side of the joint main bars (2'a in the case of Figure 3) (not shown). , it did not reach the outer main reinforcement (2a in Figure 3). For this reason, it not only does not perform its function sufficiently, but also has the disadvantage that the strength and deformability of the vertical joint are inferior.

In order to solve the above-mentioned drawbacks, the present invention relates to a method for attaching shear reinforcing bars that extend to the joint main bars located on the outer side of the joint.

1 to 4 are plan views mainly showing the joint portion, showing the construction order of the present invention. First, after inserting the reinforcing bar cage 2 into the excavated groove 1, concrete 3 is poured.Since the box 4 that covers the joint main reinforcement 2a is attached to the end of the reinforcing bar cage, there are
No concrete will be placed at this point. Although this is no different from the conventional method, in the present invention, a ladder-shaped reinforcing bar frame 5 is loosely fitted, particularly at the root of the joint main bar protruding into the case. As shown in Fig. 5, this reinforcing bar frame is constructed by arranging two reinforcing bars in parallel that will later become the vertical reinforcements 5a of the joint, and connecting a large number of reinforcing bars that will later become the shear reinforcing bars 5b of the joint. It is formed into a shaped frame. The length, diameter, and spacing of these longitudinal bars and shear reinforcing bars are determined based on structural design.

Next, after excavating the trailing underground wall, the pull-out plate 4a of the box 4 is extracted, and the box and the trailing wall excavated groove 1' are communicated and integrated (Fig. 2), and the leading wall joint inside the box is connected. A trailing wall reinforcing bar cage 2' having a joint main reinforcement 2'a to be arranged parallel to the main reinforcement 2a with a guide 9 in between is inserted (FIG. 3).

Next, the guide 9 is removed and the reinforcing bar frame is moved to a predetermined position (FIG. 4).

This movement may be carried out by an underwater jack (not shown), but as shown in Fig. 6, a pulley 6 is attached to the main reinforcing bar next to the wire 7 tied to the reinforcing bar frame.
It is preferable to change the winding direction, extend it to the ground, and tow it. Note that instead of the pulley, a reinforcing bar with a sleeve 6' loosely fitted therein may be used, which is attached to the tip of the main bar of the lowermost joint (FIG. 5).

In addition, if each adjacent reinforcing bar frame is tied together with a flexible wire material 8 such as a wire of a certain length, all the reinforcing bar frames can be moved to the predetermined position by simply moving one of the outermost reinforcing bars (tracing wall side). It can be placed in

In addition, in this example, when the joint main reinforcement is made into a lap joint, the joint main reinforcement 2a of the reinforcing bar cage 2 of the preceding underground wall is designed to be on the outside, so the ladder-shaped reinforcing bar frame 5 is loosely fitted in advance to this. However, in the opposite case, it loosely fits into the joint main reinforcement 2'a of the trailing underground wall.

Now, as shown in Figure 4, after moving the reinforcing bar frame to a predetermined position, concrete is poured into the joint part box and the trailing wall part to integrate it with the leading wall (not shown). This is the end of the process.

As a result, the shear reinforcing bars 5b reaching the outer joint main reinforcing bars are incorporated, improving the structural performance of the joint, and in particular, improving the deformability by preventing the outer joint main reinforcing bars from peeling off at the time of fracture.

In addition, although this example shows the case where the concrete of the joint part and the trailing wall part is cast as one piece, this method can also be applied to the case where the joint part's own reinforcing bar basket (not shown) is used and the concrete is cast afterwards. can.

As described above, the present invention not only facilitates the installation of structurally advantageous shear reinforcing bars by simply loosely fitting the reinforcing bar frame into the joint main reinforcement and moving it later, but also makes it possible to easily install shear reinforcing bars that are structurally advantageous. There is no wastage of materials because it is used as a reinforcing bar or longitudinal bar and as a structural member.

In addition, if adjacent reinforcing bars are tied together with flexible wires of a certain length, all reinforcing bars can be placed in the specified position by simply moving one outer reinforcing bar frame, making the work easier. Streamlined.

Furthermore, when moving the reinforcing bar frame, a method of attaching a rope, changing direction using a pulley, etc., and towing it on the ground is lighter and more economical than using a hydraulic jack.

[Brief explanation of drawings]

1 to 4 are plan sectional views of underground walls showing embodiments of the present invention in the order of construction. 5 and 6 are cutaway perspective views showing the construction stages of FIGS. 2 and 4, respectively. Note that dotted lines indicate known parts. 1, 1': Excavation groove, 2, 2': Rebar cage, 2a,
2'a: Joint horizontal reinforcing bar (joint main reinforcement), 3, 3': Concrete, 4: Case (of the joint), 4a: Drawn plate, 5: (ladder-shaped) reinforcing bar frame, 5a: (reinforcing bar frame) of)
Vertical reinforcement, 5b: Shear reinforcement, 6: Pulley, 6':
Sleeve, 7: rope, 8: flexible wire, 9: guide.

Claims (1)

[Scope of Claims] 1. In the construction of a vertical joint J in which the joint horizontal reinforcing bars 2a, 2'a at the ends of the reinforcing bar baskets 2, 2' of the leading underground wall and the trailing underground wall are overlapped with each other. ,
A ladder-shaped reinforcing bar frame 5 made up of longitudinal bars and shear reinforcing bars is loosely fitted in advance to the horizontal reinforcing bars of the joint part located on the outer side when a lap joint is made of the horizontal reinforcing bars of the joint part, and 1. A method for arranging shear reinforcing bars in a vertical joint of an underground wall, the method comprising: installing a reinforcing bar in a predetermined position, and then moving the reinforcing bar frame to a predetermined position. 2. The underground wall vertical joint section shear according to claim 1, wherein a plurality of ladder-like reinforcing bars 5 are connected to each other by a fixed length of flexible wire 8 at corresponding portions. Reinforcement reinforcement method. 3. A rope 7, one end of which is tied to a ladder-like reinforcing bar frame 5 that is loosely fitted to the base of the horizontal reinforcing bar 2a at the joint portion of the reinforcing bar cage 2, is pulled sideways, and a pulley 6 or A method for moving a ladder-like reinforcing bar frame at a vertical joint of an underground wall, which comprises changing the direction using a sleeve 6', extending it above ground, and towing it.