JPS595090B2 - PC cable arrangement method on large PC floor slab - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for arranging PC cables buried in a large PC (prestressed concrete) floor slab.

Recently, P of underground structures or other structures that require space between the girders, such as research facilities installed underground.
C floor slabs tend to be larger.

In order to make such a large PC floor slab into a boss tension type PC structure with two directions: front and back and left and right, a large number of PC cables must be placed in two directions, front and back and left and right. Each PC around the floor slab
The ends of the cables are set at almost the same height, and the PC cables are bent down from around the floor slab toward the center, so if the PC cables are spaced the same,
There will be places where the PC cable in one direction butts into the PC cable in the other direction, so in the places where the PC cable in one direction butts into the PC cable in the other direction, increase the cable spacing or bend the PC cable laterally. was.

This invention advantageously solves the above-mentioned problems because the cable arrangement work is complicated, and the cables cannot be spaced evenly, resulting in PC cables that are not straight when viewed from above. The purpose of this invention is to provide a method for arranging PC cables on a large-sized PC floor slab.

Next, the present invention will be explained in detail using illustrated examples.

In order to make this invention easier to understand, this invention will be explained using a diagram showing a square PC floor slab divided into four equal parts. In addition, a large number of front and rear extension cables 1 arranged at intervals in the left and right direction and extending parallel to each other in the front and rear direction (X direction) are connected in the required number of front and rear extension cables 1 between the center of the floor slab and the left and right peripheral surfaces B of the floor slab. Divide into extension cable groups 18 to 1E.

In addition, it has a parabolic shape with the deepest depression at the center of the floor slab, and is lined up at intervals in the front and back direction, and in the left and right direction (
A large number of left and right extension cables 2 extending parallel to each other in the Y direction) are divided into a required number of left and right extension cable groups 2A to 2E between the center of the floor slab and the front and rear peripheral surfaces A of the floor slab.

The large number of front and back extension cables 1 and the large number of left and right extension cables 2 are each located on a parabolic curved surface that is gradually depressed from the periphery of the floor slab toward the center of the floor slab.

Next, as shown in FIG. 2, the first left and right extension cable group 2A located on the floor slab center side is arranged below the first front and rear extension cable group 1 located on the floor slab center side, and At the bottom of the extension cable group 2A, there is a second front and rear extension cable group 1B.
are arranged one on top of the other, and the second left and right extension cable group 2 is placed at the bottom.
In the same manner, the third to fifth front and rear extension cable groups 1C to 1D and the third to fourth left and right extension cable groups 2C to 2D are alternately arranged so as to overlap downward.

Each cable is housed in a concrete adhesion prevention sheath, and a fixing socket is fitted to the end of each cable, but its illustration is omitted.

Next, the arrangement of each cable will be explained in more detail.

To explain the case where the floor slab is square (side length a = b), the linear shape of each cable is a parabola with the depth h of the recess, and the outer diameter of the sheath is d, as shown in Figure 3, the front and rear extension cable group 1A ~1E and left and right extension cable groups 28~2D are moved in parallel by a distance d in the vertical direction to create OlX and 02
Placed at position Y, 0□X for side A, 0□Y for side B, and height 2d from the center of the floor slab to the peripheral side of the floor slab.
As shown in FIG. 4, the front and rear extension cable groups 1A to 1E, which are divided into groups 1A to 1E, are moved in parallel so that the cables on the periphery of the floor slab are lowered by a distance of 2d than those on the center of the floor slab. Furthermore, in Fig. 3, left and right extension cable groups 2 are divided into 2-d height sections from the center of the slab to the periphery of the slab.
As shown in FIG. 4, A to 2D are moved in parallel so that those on the peripheral side of the floor slab are lowered by a distance of 2d than those on the center side of the floor slab.

Figure 5 shows the square floor slab 3 in Figure 6 divided into four equal parts along a plane parallel to and perpendicular to the periphery, passing through the center of the square floor slab 3 in Figure 6, where A is the front and back periphery of the square floor slab, and B is the left and right sides of the square floor slab. peripheral surface, and B'
indicates the central vertical plane of the floor slab parallel to the circumferential surfaces A and B.

When the cable is arranged on the square floor slab 3, the lowest position is near the center of the floor slab, the distance from the center of the sheath to the bottom surface is tl, and the distance to the top surface of the floor slab at the highest point on the edge of the floor slab is t2. Then, the front and rear and left and right sawtooth shadow lines obtained by arranging the adjacent cable groups by shifting each other by 2d in the vertical direction as described above are drawn between the peripheral surface and the center of the square floor slab in Fig. 5. If we consider that it is copied on a vertical plane, C=h+3d+t1+t2,
The value of the thickness C of the floor slab is determined.

The intersection of a plane perpendicular to the circumferential surface A in the front-rear direction and the sawtooth shadow line to said surface is the passing point of the parabola, and a plane perpendicular to the side surface B in the left-right direction and the plane B.

The intersection of W with the sawtooth shadow line becomes a passing point of the parabola, and each cable group overlaps in an orderly manner without interfering with each other's areas.

FIG. 7 shows the overlapping state of the entire cable group of one floor slab.

Generally, the thickness C of the floor slab is almost determined in many cases, and in this case, assuming the type of cable to be used, d
, tl, and t2 are also determined secondarily, so the value of t is determined as a result.

In some cases, h is determined first and then C is determined.

In the embodiment described above, the case where the front and rear extension cable groups and the left and right extension cable groups are sequentially and alternately stacked downward from the center of the floor slab toward the end of the floor slab has been described. Conversely, the front and rear extension cable groups and the left and right extension cable groups may be sequentially and alternately stacked on top of each other from the end of the floor slab toward the center of the floor slab.

The floor slab may have a rectangular or other shape.

The cable may have a shape other than a parabola, such as a trapezoidal broken line as shown in Figure 8 (or it may have a straight line in the middle with parabolas on both sides as shown in Figure 9). You can leave it there.

According to the present invention, a large number of front and rear extension cables 1 having a linear shape with a concave middle part and arranged at intervals in the left and right direction and extending parallel to each other in the front and rear direction are divided into a required number of front and rear extension cable groups, A large number of left and right extension cables 2 having a linear shape with a concave middle part and arranged at intervals in the front and rear direction and extending parallel to each other in the left and right direction are divided into a required number of left and right extension cable groups, and each of the front and rear extension cable groups is separated. Since the left and right extension cable groups are arranged so as to overlap one after another from the center of the floor slab toward the periphery of the floor slab, a large number of front and rear extension cables 1 and a large number of left and right extension cables 2 are arranged at equal intervals on a flat surface. It is possible to arrange the cables in an orderly manner while maintaining a straight line and a predetermined accurate alignment, and furthermore, cables with the same alignment can be used in the same direction, so the number of types of cables according to shape can be reduced. Furthermore, when wiring in one direction, it does not collide with wiring in the other direction, so that the wiring work can be easily performed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a cable group, Fig. 2 is a perspective view showing the arrangement of cables according to the present invention, Fig. 3 is a view showing the vertical positional relationship between the front and rear extension cables and the left and right extension cables, and Fig. 4. 5 is a diagram showing the vertical positional relationship of the front and rear extension cable groups and the left and right extension cable groups, FIG. Perspective view showing the relationship between the buttocks and the floor slab shown in Figure 7.
The figure is a schematic plan view showing the arrangement of cable groups on one floor slab, and FIGS. 8 and 9 are side views showing other linear examples. In the figure, 1 is the front and rear extension cable, IA to 1E are the first
~5th front and rear extension cable group, 2 is left and right extension cable, 2
A to 2D are the first to fourth left and right extension cable groups, 3 is the floor slab,
A is the front and rear peripheral surfaces of the floor slab, and B is the left and right peripheral surfaces of the floor slab.

Claims (1)

[Claims] 1 A large number of front and back extension cables 1 having a linear shape with a concave middle part and arranged at intervals in the left and right direction and extending parallel to each other in the front and back direction are divided into a required number of front and rear extension cable groups,
A large number of left and right extension cables 2 having a linear shape with a concave middle part and arranged at intervals in the front and rear direction and extending parallel to each other in the left and right direction are divided into a required number of left and right extension cable groups, and each front and rear extension cable group is divided into a required number of left and right extension cable groups. A method for arranging PC cables in a large-sized PC floor slab, characterized in that the left and right extension cable groups are arranged so as to be sequentially and alternately overlapped from the center side of the floor slab toward the periphery of the floor slab.