KR101523423B1 - 1-way PC slab with various level of flanges - Google Patents

Abstract

The present invention relates to a PC slab used in a PC composite method,
More specifically, the present invention relates to a 1-way PC slab which can be synthesized with an on-site reinforced concrete to economically construct a composite section corresponding to a total of 1: 1 maximum shear force and bending moment.

Description

1-way PC slabs with various slab thicknesses and various levels of flanges.

The present invention relates to a PC slab used in a PC composite method, and more particularly, to a 1-way PC slab capable of economically constructing a composite section of a PC slab and an on-site reinforced concrete.

There are 2-way method using PC girder and side beam, 2-way PC slab, and 1-way method using main girder and 1-way PC slab. Because the stranded stems and ribs contained in the 1-way PC slab replace the role of the secondary beam, using the 1-way method can reduce the volume of the concrete as much as the secondary direction using the 2-way method . Therefore, 1-way construction method is more applied than 2-way construction method at present. Here, the proportion of 1-way PC slabs accounts for about 50% of the total PC volume, and the selection of 1-way PC slabs, which greatly affects the cross-sectional thickness of composite slabs,

The slab used in the existing 1-way PC method has several disadvantages. In the double-slab method, the composite flange is thinned to the same thickness at the ends and the middle part instead of taking the stem long. As a result, it is difficult to operate as a continuous slab, or the girder and the slab joint are cracked Sometimes things happen. Multi-Ti slabs that block the end of the PC slab near the boundary of the main girder have the inconvenience that they must be buried in order to behave as a continuous slab, and it is difficult to construct due to the installation interference caused by the settlement. In the case of a half slab or a rib slab with a prestress introduced, there is no problem such as landfill for the continuous slab behavior. However, if the effective depth of the rebar is increased, there is a limit to increase the amount of the PC slab. Therefore, it is difficult to apply to structures subjected to high load.

Due to the nature of the precast using cast iron molds with very good re-usability, although the formwork of the site is difficult to form, there is no slab corresponding to 1: 1 of the resultant shear force and bending moment acting on the structure .

We would like to propose a 1-way PC slab that can make slim design of structures by making full use of the advantages of precast method.

If the slab end where the PC girder and the 1-way PC slab meet is not filled with sufficient amount of on-site reinforced concrete, there is a problem that does not behave as a continuous slab or requires additional rods. Also, the 1-way PC slab end is a site where the shear force and the momentum play a large part at the same time. Therefore, 1-way PC slabs must have sufficient composite cross-sections at the ends, and must withstand the 1-way PC slab self-weight and workload in the hypothetical phase.

Since the central part of the composite slab is mainly dominated by the bending moment, the product of the cross-sectional area of the bottom reinforcing bar and the strand and the distance of the corresponding reinforcing bar and strand from the center of gravity is much more important than the concrete thickness of the composite section. Therefore, the concrete thickness of the composite section should be thin, and the PC slab section with a long stem should be constructed so that the reinforcing bars and strands can take a large distance from the center of gravity.

In a 1-way PC slab consisting of a stem and a flange in the PC composite structure, which is composed of reinforced concrete placed on the precast concrete, and is installed between the main girders,

A plurality of stems which are continuous in the longitudinal direction of the slab and resist the shear and tensile in the hypothetical and synthetic steps are formed at regular intervals,

In order to form a thick composite slab that resists the shear force and the momentum at both ends in the longitudinal direction of the slab, a lower flange is formed at both lower portions of the stem, and a '

A slant flange is formed between the end portion in the longitudinal direction of the slab and the center portion to reduce the thickness of the composite slab from the end portion to the center portion,

In the center part of the slab longitudinal direction, the upper flange is formed on both sides of the stem, and a 'ㅜ' shaped cross section with a bottom open is formed continuously in the width direction of the slab so as to form a thin composite slab.

Stems with longitudinal stranded strands are fitted with vertical reinforcing bars to form a 1-way PC slab and on-site reinforced concrete,

The flanges are wire mesh installed and roughened to combine pre-cast concrete with on-site reinforced concrete.

In the PC composite structure, which is composed of precast concrete placed on precast concrete and composed of reinforced concrete,

If a 1-way PC slab consisting of a stem and a flange is installed with a top-opened 'ㅗ' -shaped section at the end and a bottom-opened '' '-shaped section at the center,

You can complete a composite slab that shows the best resemblance to the resultant bending moment, shear force diagram.

This makes it possible to reduce the amount of unnecessarily placed concrete and reinforcing steel, which makes it possible to construct an economical PC composite method.

1 is a perspective view of a PC slab according to an embodiment of the present invention.
FIG. 2 is a perspective view of a PC slab addition (bottom view) according to an embodiment of the present invention;
Figure 3 is an exemplary PC slab arrangement according to an embodiment of the present invention.
Figure 4 is a cross-sectional perspective view of PC slabs cut aa, bb in Figure 1;
FIG. 5 is a cross-sectional view of a PC slab longitudinal section cut at cc,
FIG. 6 is a perspective view of an assembled perspective view according to an embodiment of the present invention.
7 is a cross-sectional view of an assembly according to an embodiment of the present invention.
Fig. 8 is a cross-sectional view taken along line cc of Fig.
FIG. 9 is a cross-sectional view ('?') Section according to an embodiment of the present invention;
Figure 10 is an additional cross-sectional view ("ㅗ" shaped cross-section) in accordance with an embodiment of the present invention;
Figure 11 is a perspective view of a construction according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings, and specific details of the present invention will be described.

By analyzing the ramen structure, you can see a composite graph of shear force diagrams and bending moment diagrams. In a typical continuous beam, continuous slab structure, the end of the span is dominated by the shear force and the moment, and is dominated by the bending moment at the center. Therefore, to complete the economic structure, a 1-way PC slab with almost no 1: 1 correspondence with the resultant force graph of shear force and moment and no unnecessary part needs to be completed.

1 and 2 are perspective views of a PC slab according to an embodiment of the present invention. FIG. 3 is an illustration of a PC slab installation according to an embodiment of the present invention. FIGS. 4 and 5 are cross- Sectional perspective view.

The 1-way PC slab according to the present embodiment is installed between the main girders to support the load of the PC composite structure, and is combined with the field-inserted reinforced concrete to form a single structure.

The PC slab of the present embodiment includes a stem 100, a lower flange 200, an inclined flange 210, an upper flange 220, a strand 300, a vertical reinforcement 310, an end reinforcing vertical reinforcement 315, (320), cast-in-place concrete (400), upper reinforcement (500) and lower reinforcement (510).

The 1-way PC slab of the present invention has a plurality of stems 100 (which are continuous in the longitudinal direction of the slab and spaced along the width direction) to resist the shear force and tensile force that may occur in the step of setting the PC composite structure ). Each stem 100 is comprised of a prestressed strand 300, a vertical reinforcing bar 310, and an end reinforcing vertical reinforcing bar 315. The vertical reinforcement 310 allows the integration of the 1-way PC slab and the spotted concrete 400 and the end reinforcing vertical reinforcement 315 enhances the shear resistance after the building step and after the synthesis.

In order to make the structure less unnecessary of the composite slab as described above, the thickness of the slab except for the stem 100 was varied in the longitudinal direction of the 1-way PC slab.

At both ends, the lower flange (200) was made to increase the thickness of the composite slab so as to resist the shear force generated by the working load and the resultant force of the momentum. At the inflection point of the moment, the thickness of the composite flange is reduced by making the inclined flange (210) which can reduce the thickness of the composite slab. The central portion of the span at which the inclined flange 210 ends is made thinner by forming the upper flange 220 so that the stem and the composite flange can maintain the T-shaped cross section even if the thickness of the composite flange 230 is not thick. The 1-way PC slab of the present invention has the shape shown in Figs. 1 and 2.

The finished 1-way PC slab is installed on the field on the main direction girder (600) already installed as shown in Fig. Assembling the 1-way PC slab of the present invention side by side in a direction orthogonal to the main direction girder (600). After the assembly is completed, lower joint 510 and upper joint 500 are performed as shown in FIG. 8 is a longitudinal sectional view of the lower roots 510 and the upper roots 500. Fig.

Fig. 9 is a cross-sectional view of the PC building step cut from b-b of Fig. 1; As can be seen from the cross section, in the middle part, it shows a 'ㅜ' shaped section opened at the bottom of the hypothetical stage, and it shows that the T-shaped section is formed after the completion of the synthesis.

Fig. 10 is a cross-sectional view of the step of PC-cutting step a-a in Fig. As can be seen from the cross section, at the end, it shows the upper open 'ㅗ' type in the construction stage, and in the synthesis phase it is filled with the cast concrete (400), which creates a favorable shear thickness.

As shown in FIG. 11, when the lower reinforcing bars 510 and the upper reinforcing rods 500 are completed, the pouring concrete 400 is poured to complete the structure. When the pouring concrete 400 exhibits design strength, End reinforced vertical reinforced concrete (320) composite PC composite structure is completed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

100: stem
200: Lower flange
210: inclined flange
220: upper flange
300: Stranded wire
310: vertical reinforcement
315: End reinforcement vertical reinforcement
320: Wire Mesh
400: Field cast concrete
500: top of the field
510: field submodulation
600: Main direction girder

Claims (2)

In a 1-way PC slab consisting of a stem and a flange in the PC composite structure, which is composed of reinforced concrete placed on the precast concrete, and is installed between the main girders,
A plurality of stems which are continuous in the longitudinal direction of the slab and resist the shear and tensile in the hypothetical and synthetic steps are formed at regular intervals,
In order to form a thick composite slab that resists the shear force and the momentum at both ends in the longitudinal direction of the slab, a lower flange is formed at both lower portions of the stem, and a '
A slant flange is formed between the end portion in the longitudinal direction of the slab and the center portion to reduce the thickness of the composite slab from the end portion to the center portion,
A 1-way PC slab in which the upper flange is formed on both sides of the stem at the central portion of the slab longitudinal direction, and a 't' -shaped section opened at the bottom is formed continuously in the width direction of the slab so as to form a thin composite slab. The method according to claim 1,
A 1-way PC slab in which vertical reinforcing bars are installed on the stem where the strand of the prestressed length is arranged, and a wire mesh and roughening treatment is applied on the flange of which the level changes according to the position, so that the precast concrete and the on-site reinforced concrete are combined.

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