JPS60223574A - Tensioning of pc steel material - 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 [Industrial Field of Application] The present invention relates to a method for tensioning paw materials for prestressing concrete in a post-tensioning method.

[Conventional technology]

When using PC@ stranded wire as a tension member for a post tension member of a prestressed concrete structure, a wedge is generally used as a tensioning side anchor. After tensioning and fixing the PC steel stranded wire using a wedge, the tensile stress of the paw stranded wire decreases due to a phenomenon called "set volume" in which the wedge is drawn into the tube holding it. These PC steel strands and PO' are especially used
P
It is necessary to eliminate this set amount by re-tensioning and re-fixing the C steel material.

[Problem that the invention seeks to solve]

In erasing this set amount, the present invention does not use a coupler to connect the fixing device and the jack.
Even if the ends of the PCwi material protrude irregularly, the set amount can be easily erased.

[Means for solving problems]

In the present invention, the PaS material is pulled out of the concrete through a hole for Po steel material provided in the poured concrete, and the PaS material is placed under direct tension with a hydraulic jack that is in contact with an anchor plate on the concrete surface, and then inserted in advance around the POW4 material. One end of the cylindrical body is brought into contact with the anchor plate, and the other end of the cylindrical body is press-fitted between the inner surface of the cylindrical body and the Po steel material, and the pc
, After fixing the iri material to the anchor plate, in order to adjust the tensile load depending on the set amount, insert a cap nut-shaped wedge stopper with a Po steel material insertion hole at the bottom into the Po steel material and screw it onto the outer periphery of the cylinder body. Press the end of the cylinder press-fitted into the cylinder body, then apply a hydraulic jack to the anchor plate and tension the Po steel material directly with the hydraulic jack, and in this state, attach the threaded cylinder screwed to the outer periphery of the cylinder body to the anchor plate side. The anchor plate is rotated and crimped onto the anchor plate.

〔Example〕

Fig. 1 shows an embodiment of the fixing tool used in the present invention. inside P
o A cylindrical wedge λ that has a steel insertion hole and is inserted from the small diameter side from the large diameter side to the small diameter side of the inner surface of the cylinder /, and the inner surface of the cylinder / is attached to the outer periphery of the large diameter side. A wedge holder 3 in the form of a cap nut, which has a cylindrical body pushed in and a bottom that closes one end of the cylindrical body, and has a paw material insertion hole in the bottom; Consists of a screw tube with both ends open.

As shown in Fig. 2 (A), this fixing device is designed to hold a PC steel material S drawn out through a hole 7 for Po steel material provided in the poured concrete B, using hydraulic pressure to bring it into contact with an anchor plate g on the surface of the concrete 6. While directly under tension with jacks, bring one end of the cylinder/ which has been fitted in advance around the left side of the PC steel material into contact with the anchor plate g, and insert it between the inner surface of the cylinder/ and the PC steel material from the other end of the cylinder/. Press in the hole λ and fix the left side of the pavs material to the anchor plate g. At this time, the threaded tube g is placed close to the center of the cylinder so that it does not come into contact with the anchor plate g. If this state is left for a while, the stress in the PaS material will decrease from the initial tensile stress due to the "set amount" phenomenon in which the wedge is drawn into the cylinder.

Therefore, as shown in FIG. 2(b), the stopper 3 is inserted through the PC steel material S, and the stopper 3 is screwed into the cylinder until it touches the cylindrical body at a distance of λ. Then, a ram chair 9 is placed on the anchor plate g, a hydraulic jack 10 is placed, and the Po steel material 5 is directly re-tensioned with the hydraulic jack 10.

When the PC steel material S is tensioned, the wedge is held down by the rail stop 3 so that it does not come out from the cylinder, so the cylinder moves together with the pa #4 material to the hydraulic jack 10 side, and the cylinder A gap is created between / and anchor plate &. Therefore, the threaded tube g is rotated and moved, and it is crimped onto the anchor plate g as shown in Fig. 2(d), and the ram chair 9 and hydraulic jack 10 are removed and re-tensioned as shown in Fig. 2(d). end.

〔Effect of the invention〕

In the method of the present invention, when erasing the set amount, the 20W4 material is tensioned directly with the jack without using a coupler to connect the fixing tool and the jack, so pr44
Even if the ends of the material protrude unevenly, it can be easily re-tensioned, and since the steel wire is directly tensioned, there is no intervening elongation of intermediate members such as couplers, and the amount of tension can be accurately determined. During re-tensioning, the biting into the PaS material is stopped by the cap nut-shaped wedge, so that no further set amount occurs after re-tensioning.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an embodiment of the POm material tension measuring garment used in the present invention, and Fig. 2 (A), (B), and (C) (→ is a diagram showing the method of the present invention in order. Yes.／...Cylinder body, K...I, 3...Wedge stopper, Da...Screw tube,
Left: POlili material, Otsu: concrete, 7: hole, g: anchor plate, 9: lamb chair, 10:
・Hydraulic jack.

Claims (1)

[Claims] (1) The PC steel material is pulled out of the concrete through the hole for the prestressed steel material made in the poured concrete.The PC steel material is pre-inserted around the PO steel material under direct tension with a hydraulic jack that is in contact with the anchor plate on the concrete surface. One end of the cylindrical body is brought into contact with the anchor plate, and a wedge is press-fitted from the other end of the cylindrical body between the inner surface of the cylindrical body and the PC steel material, and the pcJ
After fixing the material to the anchor plate, in order to adjust the tensile load depending on the set amount, insert a cap nut-shaped wedge with P and O steel insertion holes at the bottom into the PC steel material and screw it into the outer periphery of the cylinder. Press the end of the rod press-fitted into the cylinder, and then apply the hydraulic jack to the anchor plate.
A method for tensioning PO steel materials, in which the cil material is directly tensioned with a hydraulic jack, and in that state, the threaded cylinder screwed onto the outer periphery of the cylinder body is rotated toward the anchor plate side and crimped to the anchor plate.