JPH03122343A - Single span pc slab construction method - Google Patents

Abstract

PURPOSE:To twist beams in the reverse direction to the twisting by load so as to reduce the flexure of a slab by providing the beams on both ends of the slab upward to a PC slab, or tensing a PC steel material between beams being provided downward at both ends of the slab. CONSTITUTION:Upward beams 3 are provided at both ends, and a concrete slab 1, wherein a PC steel wire 2 is buried in unbonded condition, is made. Next, prestress force is given to the steel wire 2, whereby the beams 3 are twisted in the reverse direction to the case of conventional downward beams, and the slab 1 is lifted up further additionally besides the lifting force by the steel wire 2 so as to double the effect. Moreover, a PC steel wire 5 is provided and tensed between the beams 4 being provided downward at both ends, and the twisting diriction of the beam 4 is made reverse to the twisting direction by load so as to double the slab lifting effect. Hereby, a single PC span, which was considered impossible in the past, can be constructed, and prestress force can be introduced enough.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention relates to a single-span PC slab construction method in which steel material for prestressed concrete (PC) is placed in a single-span PC slab and tensioned to apply prestress force. be.

[Prior art] Generally,! @ In a single span PC slab in which both ends of the slab 6 are supported by beams 7 as shown in Figure 3 (A) and (B), the beams 7 and 7 at both ends supporting the slab 6 are P as shown in Figure 4.
Since the Cl material 8 twisted, it was impossible to construct a fixed slab.

[Problems to be Solved by the Invention] The present invention was made to solve the problems of the conventional single-span PC slabs described above, and its purpose is to offset or reduce the deflection of the slab due to load. hand,
Single span P that does not reduce the lifting effect of the slab and can be expected to have sufficient prestressing force due to the prestressing steel material.
Our objective is to provide the C-slab construction method.

[Means for Solving the Problems] The single span PC slab construction method of the present invention, in a single span PC slab using PCGQ material, twists the beams at both ends that support the slab in the opposite direction to the twist caused by the load. It is characterized by canceling out or reducing the deflection due to the load, and the beams at both ends are integrally constructed so as to be superposed on the slab, or the beams at both ends are constructed under the slab. The beam is constructed integrally with the beam, and the intermediate portions of both beams are made of PCgA material to tension each other to cause twisting. .

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a concrete slab, within which a PC steel wire 2 is buried in an unbonded state in one or two directions. The PC steel wire 2 is given a prestress force so as to cancel out the bending moment caused by the load applied to the slab.

Reference numerals 3 denote beams at both ends, which are integrally constructed above the slab 1, that is, in a superposed state.

Therefore, this upper beam 3 twists in the opposite direction to the conventional lower beam, and in addition to the lifting force of the PC steel wire 2 in the slab, the slab 1 is further lifted upward.
Double the effect.

FIG. 2 shows another embodiment in which the beams 4 at both ends are constructed integrally under the slab 1, that is, in a substratum, as in the conventional manner, and these beams 4.4 The middle part of the beam 4 is tensioned by a prestressed steel material 5 to reverse the twisting direction of the beam 4 from the twisting direction due to the load, thereby doubling the effect of lifting the slab.

[Effects of the invention] 1) By constructing the beams at both ends of the single-span slab so that they are superimposed on the slab, the reduction in the lifting effect of the slab is reduced, and sufficient prestressing force from the prestressing steel material can be expected. I can do it.

2) When the beams at both ends of a single-span slab are subscripted, the intermediate portions of the beams can be tensioned with PC steel to double the effect of lifting the slab.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a concrete slab showing one embodiment of the single span PC slab construction method of the present invention, Fig. 2 is a sectional view of a concrete slab showing another embodiment, and Figs.
) are plan views of single-span PC slabs, and FIG. 4 is a cross-sectional view showing the twisting of beams at both ends in a conventional single-span PC slab. 1...Slab, 2...PC steel wire, 3.4...Beams at both ends 5...PC steel material.

Claims (1)

[Claims] 1. In a single-span PC slab using PC steel, the beams at both ends supporting the slab are twisted in the opposite direction to the twisting caused by the load, thereby offsetting or reducing the deflection of the slab due to the load. Single span PC slab construction method. 2. The single-span PC slab construction method according to claim 1, wherein the beams at both ends are integrally constructed with the slab superimposed. 3. Claim 1, characterized in that the beams at both ends are integrally constructed with the slab subtended, and the intermediate portions of both beams are mutually tensioned by a prestressed steel material to cause twisting.
Single span PC slab construction method described in .