JPH0722418Y2 - 3D truss muscle with prestress - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a three-dimensional truss reinforcement reinforced by the introduction of prestress, and is used, for example, in the floor portion of a building structure.

[Conventional technology]

Other types of floor construction construction methods have been developed in order to save labor in construction, and one of them is a construction method in which a steel plate reinforced by a space truss is used as a discard form (for example, Japanese Patent Laid-Open Publication No. Sho.
59-109645).

The three-dimensional truss reinforcement used in the above method is composed of a plurality of rebars constituting the upper chord member and the lower chord member, and a lattice reinforcement that connects the rebars in a truss shape, and receives the weight of the concrete weight at the time of construction, etc. It enables prefabricated construction.

[Problems to be solved by the device]

However, if the space truss is low in rigidity and has a large span, it may cause a large deflection due to the load during construction.The conventional method of dealing with the deflection is to peel the rib when manufacturing the space truss. , I can't span a big span without supporting work.

The present invention is intended to solve the above-mentioned problems in the space truss muscle.

[Means for Solving the Problems]

In this device, prestressing with both ends of the three-dimensional truss muscle as fulcrums applies a suspending force to the center and suppresses bending.
That is, the two upper chord members that are fixed by sandwiching the upper portion of the lattice reinforcement and the lower portion of the lattice reinforcement are fixed and the space between them is widened.
In a three-dimensional truss reinforcement consisting of a lower chord of a book, a tension material is arranged in a catenary form inside the rebar, and a support metal having downward concave portions formed at the middle and upward concave portions at both ends is used. Fit the lower part of the lower chord member to the lower side of the lower chord member, fit the tension member in the middle concave part, fix both ends of the tension member to the fixing metal fittings provided at both ends of the upper chord member, and introduce the tension force to the tension member. There is.

If this three-dimensional truss is used to reinforce a steel plate for a discarding form, for example, it will not be excessively bent and can be spanned over a large span without supporting work.

A normal PC steel material can be used as the tension material.

〔Example〕

 Next, the illustrated embodiment will be described.

FIG. 1 shows an outline of the three-dimensional truss muscle of the present invention. The details of the ends are shown in FIGS. 2 (a) and 2 (b), and FIGS. 3 (a), 3 (b) and 4 are shown. The details of the central part are shown.

The three-dimensional truss reinforcement in this embodiment is composed of two upper chord members 1 provided in close proximity to each other and two lower chord members 2 with an increased distance.
The cross section perpendicular to the longitudinal direction of the three-dimensional truss reinforcement is formed into a substantially triangular shape, and the upper portion of the lattice reinforcement 3 in which the reinforcement is processed into a lattice shape is sandwiched between the upper chords 1 and 1, and the lower chords 2 and 2 are expanded to expand the lattice reinforcement 3. The lower part is fixed to the lower chord members 2 and 2 by welding or the like.

In the figure, 4 is a tension member, which is arranged in a catenary form inside the lattice reinforcing bar configured as described above, and by applying a tension force to this tension member, prestress is introduced to the entire space truss muscle. Prevents deflection due to load.

The three-dimensional truss muscle can be manufactured as follows.

First, the tension member 4 is arranged inside the space truss as close to the upper chord member 1 as possible, and the tension member 4 and the end portion of the upper chord member 1 are connected to the tension member 4 by the attachment end fixing hardware 5.

Next, insert a jig between the tension material 4 and the upper chord material 1,
With the upper chord member 1 as a fulcrum, the tension member 4 is pushed downward.

At the stage where the tension member 4 is lowered to the level of the lower chord member 2, the central support metal 6 is attached to the lower chord member and the tension member 4 is fixed to the lower chord member level.

2 (a) and 2 (b) show the details of the end fixing hardware 5, which is used for fixing the concave member 5a for inserting the end of the upper chord member 1 and the tension member 4 with the nut 7 or the like. It is composed of a fixing unit 5b.

3 (a), (b), and FIG. 4 show the details of the central support member 6, and tension is placed in the middle of a horizontally long member that straddles between the lower chord members 2 at the lower end of the space truss. Downward recesses 6a for fitting and locking the material 4 are formed, and at both ends, upward recesses for fitting and locking the lower chord material 2 under and locking.
6b is formed.

[Effect of device]

Since the three-dimensional truss muscle of this invention has a structure in which the prestress generated by applying a tension force to the suspension line-shaped tensioning material with both ends as fulcrums gives a suspension force to the center and suppresses bending, It is possible to reduce the flexure in the like.

Moreover, by using a supporting metal member having a downward concave portion formed in the middle for locking the tension member and having upward concave portions at both ends, the upward supporting force can be reliably transmitted to the lower chord member.

In addition, when applied to a discard formwork structure for reinforcing a three-dimensional truss, it can be spanned over a large span without supporting work without causing excessive bending.

[Brief description of drawings]

FIG. 1 is a perspective view showing the outline of the three-dimensional truss muscle of this invention,
2 (a) and 2 (b) are a front view and a plan view (only the upper surface portion) of the portion A in FIG. 1, FIG. 3 (a),
FIG. 4B is a front view and a plan view (only the lower surface portion) of the B portion of FIG. 1, and FIG. 4 is a sectional view taken along the line I-I of FIG. 3A. 1 ... Upper chord material, 2 ... Lower chord material, 3 ... Lattice rebar, 4 ...
… Tension material, 5 …… End fixed hardware, 6 …… Center support hardware.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-109645 (JP, A) JP-A-2-197673 (JP, A) JP-A-63-156136 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A three-dimensional truss bar consisting of two upper chord members fixedly sandwiching an upper part of a lattice reinforcing bar and two lower chord members fixing a lower part of the lattice reinforcing bar and having a wide space between them. Material is arranged in a catenary form, using a support metal with a downward concave formed in the middle and upward concaves at both ends, the concaves at both ends are fitted to the underside of the lower chord, and the tension material is placed in the intermediate concave. A three-dimensional truss muscle with prestress introduced, wherein both ends of the tension member are fixed to fixing fittings provided at both ends of the upper chord member, and a tension force is introduced into the tension member.