JPS6037352A - Floor structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides unbonded 1) C111II!
This relates to a floor structure in which PC steel materials such as i1 are arranged.

Conventionally, when placing PC steel members in a reinforced concrete slab and applying a lifting force, the lifting force per PCC steel member was calculated by jJ, the pitch of the PC steel members was determined, and this was applied to the entire slab. However, with this method, the lifting force at the end span does not work very effectively due to the restraint of the beam.

Therefore, the present invention attempts to obtain the same effect as the conventional one with a smaller number of llCm materials by arranging the prestressing steel materials concentratedly only in the central span of the slab and extending them so that they work more effectively. .

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a bending moment diagram of a slab generally fixed on four sides. To simplify the explanation, if we take the short side direction, which is the main reinforcement direction, the bending moment is MXI, MX
It will be like 2.

FIG. 2 is an explanatory diagram of a method for controlling cracks.

When controlling cracks, the range exceeding the bending cracking moment MCR (
PC steel material 1 is placed only inside the LCR) to compensate for the excess moment at the hatch part. Therefore, the PCgA material 1 is placed only in the area where the bending cracking moment MCR is exceeded, prestress is applied, and the bending moment distribution after the lifting force is applied is as shown in a.
) can be kept below MCR, and target 1 is fully achieved.

Also, when a part of the load is borne by the prestressing steel material, as explained in Fig. 2, if the moment borne by the reinforcing bar is MS for the bending moment distribution of the set load, then the exceeding range LS It is only necessary to arrange PCuA material to compensate for the excess moment at the hatch part. (See FIG. 3) An example of this is shown in FIG. 4, in which the PC steel material 1 is placed and extended only approximately in the center of the slab 2 surrounded by columns 4 and beams 3.

Since the present invention is configured as explained above, it is possible to achieve the same effect as the conventional construction method with a small number of PC steel materials, and also to save resources of PC steel materials.
This contributes to lower construction costs.

[Brief explanation of the drawing]

Figures 1 to 3 are for explaining the present invention.
The figure shows the bending moment diagram when the four sides of the slab are fixed.
2 and 3 are explanatory diagrams of a method for controlling cracks, and FIG. 4 is a plan view of an embodiment of the present invention. 1...PC steel material 2...Slab 3...Beam 4...Column MXI...End bending moment MX2...Central bending moment MCR...Bending cracking moment MS...Reinforcement bar Loading moment LCR... Range exceeding the bending cracking moment LS... Range exceeding the load moment of reinforcing bars LX... Inner dimension in the short side direction LM... Inner fit in the long side direction 1 method Patent Applicant Obayashi Corporation Representative Susumu Tamori Figure 1 Figure 1jiB Figure 4 → Figure 2 Figure 4

Claims (1)

[Claims] In a reinforced concrete slab, a floor structure characterized by placing prestressing steel only in the center of the span, extending it, and applying tension.