JPS6056675B2 - Joint structure between steel frame and concrete in prestressed concrete panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joint structure between a steel frame and concrete in a prestressed concrete panel.

In the prestressed concrete panel structure with steel frames attached to all four sides, as shown in Fig. 1, the steel frame 1 consists of a pair of flanges 2 and 3 and a web 4 provided between these flanges 2 and 3. Concrete 5 is poured into the internal space. Then, a plurality of horizontal PC copper rods 6 and vertical PC copper rods 7 of the tightening type are provided penetrating the concrete web 5 and the web 4, and prestressing is applied to the concrete 5. According to the structure in which the frame 1 is attached, the steel frame 1 becomes the formwork for the concrete 5.

Since the O steel frame 1 serves as a fixing fitting for the PC copper rod 6, no special fixing fitting is required. 〇The panel can be manufactured in units of the size of the steel frame 1.

The connection between O units is completed only by welding.

There are advantages such as Further, such a structure is effective as a structural member in terms of both rigidity and deformability when a static load is applied, for example. However, when repeated loads were applied, cracks occurred in the copper frame 1 and the PC copper rods 6 and 7, resulting in low fatigue strength. In addition, a gap is created between the end of the flange 2 or 3 on the tension side and the concrete 5, and from this gap, for example, when the panel is used in the ocean or a structure, seawater may enter, resulting in the durability of the steel material. This will lead to a decline in sexuality. The web 4 and the concrete 5 are only connected by the PC copper rods 6 and 7, and no adhesive force can be expected at the surface shaft between the two, so as soon as the effective pre-stress disappears, Peel off. As a result, a large tension is applied to the PC copper rods 6 and 7 due to the load, and a large bending deformation occurs in the web 4. Therefore, the fatigue strength of the PC steel bars 6 and 7 decreases, and fatigue cracks occur in the web 4 due to bending deformation. The present invention provides a structure for connecting a prestressed concrete panel with a steel frame concrete that can solve the above-mentioned problems, and one embodiment thereof will be described below with reference to FIGS. 2 to 8. 10 is a copper frame with a pair of upper and lower flanges 11,
12, a web 13 connecting the middle portions of the flanges 11 and 12 in the width direction, and a plurality of ribs 14 arranged on the outside of the web 13. 15 is entered.

Reference numeral 16 indicates a plurality of horizontal PC steel rods that are disposed through the concrete 15 and the web 13, and are passed through the sheath 17, with threaded portions 16a formed at both ends protruding outside the web 13, and washers. 18 and is tightened with a nut 19.

20 is a similar vertical PC steel bar, 21 is a sheath, 20a is a threaded portion, 22 is a washer, and 23 is a nut.

Between the horizontal PC steel rods 16 and between the vertical PC copper rods 20, a long one protrudes inward from the inner surface of the web 13 than the tips of the flanges 11 and 12.
A point J-shaped dowel 24 is provided to protrude, and from both sides of the one-point J-shaped dowel 24, short one-point I-shaped dowels 25 that do not protrude inward beyond the tips of the flanges 11 and 12 are provided. Note that these dowels 24 and 25 are arranged in two stages, upper and lower. Said 1 point I type dowel 2
5 and along the inner surface of the web 13 at intervals. A two-point dowel 26 whose both ends are welded is provided between the flanges 11 and 12. Then, a corner sealing material 28 is provided at the corner portions of the flanges 11, 12 and the web 13 via an adhesive 27, and at the inner tips of the flanges 11, 12! An edge sealing material 30 is provided via an adhesive 29. These sealing materials 2
8 and 30 are made of rubber, for example, and are made to be easily tensioned like O-rings. Note that the panels are joined by welding 31. According to the above structure, the web 13 and the concrete 15 are positively connected by a one-point I-shaped dowel 25.

However, if there are only such short 1-point I-shaped dowels 25, stress will be placed on the surroundings of the 1-point I-shaped dowels 25, and tensile cracks will occur in the concrete 15 around the 1-point I-shaped dowels 25, resulting in frame breakage. There is. To prevent this, the concrete 15 is strongly connected by a long one-point J-shaped dowel 24. In addition, the web 13 and the concrete 1 are connected by these dowels 24 and 25.
Increase the moment of inertia of the joint position No.5. For example, when a load is applied from the upper surface side in FIG. 4, a compressive force is mainly applied to a point X on the compression side, and a rotational force is generated in the concrete 15 about the point X. Therefore, the Y point of the concrete 15 tries to deform the flange 12 on the tension side. When this deformation occurs, not only is a significant bending stress generated in the flange 12, but also an opening is formed at the flange end Z, which causes a decrease in durability due to the intrusion of seawater.
This problem is solved by preventing the flange 12 from deforming using the two-point dowel 26. Note 2
The point dowel 26 also serves to connect the copper frame 10 and the concrete 15. When such an opening as described above occurs, seawater intrudes, causing deterioration of the concrete 15, corrosion of the copper plate, and stress corrosion fracture of the PC steel bars 16 and 20.
This problem is solved by sealing materials 28 and 30 that are crimped onto the steel plates. That is, when the concrete 15 moves, the concrete 15 always pushes the two types of sealants 28 and 30, so that watertightness can be satisfied. In addition, in FIGS. 7 and 8, M indicates a crimping portion. As described above, according to the present invention, the web and the concrete can be positively bonded by the short one-point I-shaped dowel, and the stress is placed around the one-point I-shaped dowel, causing tensile cracks in the concrete. This can be prevented by using a long 1-point J-shaped dowel to further strengthen the bond between the concrete and the 2-point dowel to bond the concrete and the copper frame together. The bond can be made even stronger.

Due to these features, the concrete and the copper frame can be firmly joined together without any cracks or the like. The two-point dowel prevents deformation of both flanges due to compressive force, thereby significantly reducing the separation between the copper frame and concrete, improving fatigue strength, and preventing deformation. It is possible to reduce the intrusion of seawater due to the occurrence of openings at the end of the flange, which is the cause, and it is possible to minimize the decrease in durability due to the intrusion of seawater. In addition, when an opening occurs, seawater enters, causing deterioration of the concrete, corrosion of the copper plate, and stress corrosion rupture of the PC copper rod. This can be solved by preventing infiltration.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing a conventional example, Figs. 2 to 8 show an embodiment of the present invention, Fig. 2 is a plan view, and Fig. 3 shows the main components with concrete removed. Fig. 4 is a cross-sectional view taken along A-A in Fig. 3, and Fig. 5 is a cross-sectional view taken along B-B in Fig. 3.
6 is a sectional view taken along the line C--C, and FIGS. 7 and 8 are enlarged views of main parts in FIG. 6. 10... Steel frame, 11, 12... Flange, 13... Web, 15... Concrete, 16... Horizontal PC steel bar, 20...・・・Vertical PC
Steel rod, 24...1 point J type dowel, 25...
...1 point I type dowel, 26...2 point dowel, 28...corner seal material, 30...
...Edge sealing material.

Claims (1)

[Claims] 1. Concrete is poured into the internal space of a steel frame consisting of a pair of flanges and a web provided between the middle portions of these flanges, and a tightenable horizontal PC steel rod and a vertical PC steel rod are inserted through the concrete and the web. In a prestressed concrete panel having a plurality of steel bars, a long one-point J-shaped dowel protrudes inward from the inner surface of the web beyond the tip of the flange; A short 1-point I-shaped dowel that does not protrude to the side is provided protrudingly, and a 2-point dowel that runs along the inner surface of the web at a distance is installed between both flanges, and a corner seal is installed at the corner between the flange and the web. A joint structure between a steel frame and concrete in a prestressed concrete panel, characterized in that an edge sealing material is provided at the inner tips of both flanges.