JP2529611B2 - Arrangement structure of tendons - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an arrangement of tendons that are slidably arranged in a flat slab that constitutes a floor slab of a building by rigidly connecting columns. It is about structure.

[Prior Art] In recent years, flat slabs are often used in structural construction because of the fact that beams need not be installed between columns and the structure is simple. Unlike ordinary slabs, flat slabs are concrete-based plates that form a floor slab of a building by rigidly connecting slabs and columns that directly support the slabs without using beams.

Here, in general, reinforcing bars may be arranged in the flat slab, and a tendon (tension material) may be internally provided in the flat slab to improve the strength of the flat slab or reduce the slab thickness. Such an inner structure protects the tendon by inserting the tendon into the sheath embedded in the flat slab and injecting the grout into the sheath, and causes the tendon to adhere.

More recently, since grouting is not necessary, it is often used to install an unbonded tendon in a flat slab for the reasons such as the cost and labor required for grouting, and the fact that there is no need to harden the grout. There is. The unbonded tendon is internally provided in the flat slab without grout, and the surface of the tendon is protected with an anticorrosive agent to prevent adhesion.

[Problems to be Solved by the Invention] In the conventional arrangement structure of unbonded tendons, the tendons 1 are arranged in parallel to the column row lines 2 as shown in FIG.

Here, the present inventor, if the intersection of the tendons in the flat slab is a column line, and if the tendon is arranged in the middle between two adjacent columns on the column line, the flat slab itself occurs. It has been found that the stress drastically reduces the stress generated in the flat slab as compared to the prior art, namely, the case where the tendon is arranged with respect to the column line.

The present invention has been made in view of such circumstances,
The object is to provide an arrangement structure of tendons that can remarkably reduce the stress generated in the flat slab as compared with the prior art.

[Means for Solving the Problem] The gist of the present invention is to provide a flattened slab which is an object to which columns are rigidly connected and which constitutes a floor slab, and a tendon is embedded in the flattened slab. Arrangement structure of, the intersection of the axis of the plurality of tendons arranged in the flat slab is located on the column line, and the intersection is located in the middle of two adjacent columns on the column line, Further, the tendon arrangement structure is characterized in that the axis of the tendon is located on a straight line connecting the midpoints of two adjacent columns on mutually orthogonal column rows.

[Operation] The intersection of the axes of the plurality of tendons arranged in the flat slab is located on the column line, and the axis of the tendon is on a straight line connecting the midpoints of two columns adjacent to each other on the column lines orthogonal to each other. Since the tendons are arranged so that they are located, the slab around the column is surrounded by the slab with high rigidity and the slab on the column line with high rigidity, and is surrounded by the slab with high rigidity. Since the length of the tendon that connects the columns is short and more effective prestressing force can be introduced, the slab rigidity around the column is increased,
Therefore, the stress generated in the slab may be considered by considering the portion surrounded by the diagonal lines in FIG. 1, and the stress generated in the flat slab itself can be drastically reduced.

EXAMPLES Examples of the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified. , It is just an example of explanation.

The arrangement structure of the tendon according to this embodiment will be described with reference to FIGS. 1 and 2.

In this embodiment, unbonded tendon is used as the tendon. As shown in FIGS. 1 and 2, the arrangement structure of the unbonded tendons has a flat slab S that is a floor slab F formed by rigidly connecting columns C,
In the arrangement structure of the unbonded tendons 10 that are slidably arranged, the intersection points 10a of the axes of the plurality of slidable unbonded tendons 10 arranged in the flat slab F are on the column row line, and the column row. The intersection 10a is located in the middle of two adjacent columns C on the line. The axis of the unbonded tendon 10 is located on the straight line connecting the midpoints of the two adjacent pillars C on the pillar row lines orthogonal to each other.

The column line is a grid pattern in a plan view, that is, the columns C are arranged at equal intervals in the XY direction in FIG.

Therefore, in the present embodiment, as shown in FIG. 1, the axis line of the unbonded tendon 10 also has a grid shape in which each side has an equal length, and the axis line of the unbonded tendon 10 is 45 with respect to the column line. It makes an angle of °. Reference numeral 30 is a drop panel, and reference numeral 40 is a column capital.

As a method for constructing the floor slab F according to the arrangement structure of the unbonded tendons 10, any method suitable for carrying out the present invention, such as a conventional technique, may be used.

Next, the function and effect of the arrangement structure of the unbonded tendons configured as described above will be described.

In this embodiment, the intersection 10a of the axes of the plurality of unbonded tendons 10 arranged on the flat slab S is the column line 20.
Since the unbonded tendon 10 is arranged so that the axis line of the unbonded tendon 10 is located directly above and connecting the midpoints of two adjacent columns 30 on the column row lines 20 orthogonal to each other, The slab S around 30 is the slab S on the column line 20 with high rigidity and the unbonded tendon 10
By being constrained in a triangular shape by and, the unbonded tendon 10 that is surrounded by the highly rigid slab S and that connects the column row lines 20 can also be short, and a more effective prestressing force can be introduced. The rigidity of the surrounding slab has increased,
Therefore, the stress generated in the slab S may be considered by considering the portion surrounded by the diagonal lines in FIG. 1, and the stress generated in the flat slab S itself can be drastically reduced.

A more specific description with reference to FIG. 1 is as follows.

Generally, when considering a square grid of a × a as a slab, the stress becomes maximum at the end by the formula of fixed slab on all sides, and it is expressed as M _X1 = 1/12 × w _X × a ² .

Here, w _X = w × a ⁴ ÷ (a ⁴ + a ⁴ ) = 0.5w {w: design load (t / m ² )} According to the arrangement structure of the unbonded tendons according to this example, the apparent bending rigidity is E × 1 (E: Young's modulus, I: second moment of area A increases, and the stress state is determined by the virtual fixed object surrounded by the chain double-dashed line in FIG. 1 a × a = The slab stress is close to (2 ^0.5 a / 2) × (2 ^0.5 a / 2).

Considering the slab stress of (2 ^0.5 a ÷ 2) × (2 ^0.5 a / 2) approximately, M _X2 = 1/12 × w _X × (2 ^0.5 a / 2) ² = 1/24 × w _X × a ² = 1/2 × M _X1 , which is half the stress of the unbonded tendon without wiring.

Therefore, the stress generated in the flat slab S itself can be drastically reduced. As a result, according to the present invention, the thickness of the flat slab S can be made thinner than that of the prior art, the cost required for constructing the floor slab F can be reduced, and consequently the cost required for constructing the building can be reduced. You can

Although the flat slab S having a capital is used in the present embodiment, the scope of the present invention is not limited to the flat slab S, and other things such as a flat slab S without a cap are included in the present invention. It can be applied to any suitable one for carrying out the invention.

Further, although unbonded tendon was used as the tendon, the scope of the present invention is not limited thereto, and the bonded tendon can be used in the present invention.

Further, the intervals of the pillars C are equal intervals, but the scope of the present invention is not limited thereto, and in the present invention, for example, different intervals can be set in the X direction and the Y direction in FIG. . In such a case, as shown in FIG. 3, the intersection point 10a of the axis of the unbonded tendon 10 is on the pillar line, and the unbonded tendon 10 is located between two adjacent pillars on the pillar line.
The unbonded tendon 10 is arranged so that the intersection point 10a of the axis lines is located.

Further, in the present invention, the flat slab S may be reinforced or unreinforced.

Further, as the unbonded tendon 10, a material suitable for carrying out the present invention can be used.

EFFECTS OF THE INVENTION The present invention is such that the intersections of the axes of the plurality of tendons arranged in the flat slab are located on the column line, and connect the midpoints of two columns adjacent to each other on the column lines that are orthogonal to each other. Since the tendon is arranged so that the axis of the tendon is located on a straight line, the slab around the column is surrounded by the slab with high rigidity by being constrained in a triangular shape by the slab on the column line with high rigidity and the tendon. In addition, the length of the tendon connecting between the column rows can be shortened, and more effective prestressing force can be introduced, so the slab rigidity around the column is increased, and therefore the stress generated in the slab is surrounded by the diagonal lines in Fig. 1. It suffices to consider the open portion, and the stress generated in the flat slab itself can be drastically reduced. As a result, according to the present invention, the thickness of the flat slab can be made thinner than that of the prior art, the cost required for building the floor slab can be reduced, and the cost required for building the building can be reduced. .

[Brief description of drawings]

1 and 2 show one embodiment of the present invention. FIG. 1 is a plan view showing the arrangement structure of an unbonded tendon, FIG. 2 is a perspective view of a flat slab, and FIG. 3 is an unbonded tendon. FIG. 4 is a plan view showing another embodiment of the arrangement structure of FIG. 4 and FIG. 4 shows a conventional example. F ... Floor slab, S ... Flat slab, C ... Pillar, 10 ...
Unbond Tendon, 10a ... Intersection, 20 ... Column line, 30
...... Drop panel, 40 …… Column capital,

Claims (1)

(57) [Claims] 1. An arrangement structure of tendons in which a tendon is embedded in a flat slab which is an object to which columns are rigidly connected and which constitutes a floor slab, and a compressive stress is generated on the lower surface of the flat slab. The intersections of the axis lines of the plurality of tendons arranged in the column are located on the column line, and the intersections are located in the middle of two columns adjacent to each other on the column line, and are adjacent to each other on the column lines orthogonal to each other. The arrangement structure of the tendon, wherein the axis of the tendon is located on a straight line connecting the midpoints of the two pillars.