JP3609388B2 - PC steel stranded wire fixing tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a PC steel stranded wire for increasing the strength of a concrete body such as a concrete bridge girder, for example, a concrete of a floor slab portion of a bridge girder, a number of PC steel stranded wires in a transverse direction are previously spaced in the longitudinal direction of the floor slab. The present invention relates to a fixing tool for embedding and holding a state in which tension is applied to a PC steel stranded wire after hardening of concrete.
[0002]
[Prior art]
Many concrete PC steel strands are pre-arranged on the floor of the concrete bridge girder before placing the concrete, and after fixing the concrete, the fixing tool (fixed side fixing tool) supported on one end of the PC steel strand is concrete. Abutting and supporting the side wall of the body, pre-tension is applied by hydraulic jacking from the other end of the PC steel strand, and the other end of the PC steel strand is fastened to the concrete by another fixing tool (clamping side fixing tool). It is in contact with and supported by the other side wall.
[0003]
Since the PC steel stranded wire embedded in the concrete body is covered with the covering sheath, rust does not occur. However, the conventional PC steel stranded wire fixing device is only exposed to the outside air by engaging two or three wedges sandwiching the end of the PC steel stranded wire with the conical hole of the tightening sleeve. The sleeve with a rust preventive agent is housed inside a box fixed to the side wall of the concrete body, and the end of the PC steel strand is exposed to rainwater over a long period of time, causing rust. There is a problem that the pre-tension that the PC steel stranded wire exerts on the concrete body changes over time.
[0004]
[Problems to be solved by the invention]
Therefore, in view of the above-mentioned problems, the object of the present invention is to maintain a state in which a pre-tension is applied to a PC steel stranded wire and not to rust the end of the PC steel stranded wire exposed to the outside from the concrete body. An object of the present invention is to provide a fixing device for PC steel stranded wire.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the configuration of the present invention is such that a water stop pipe is inserted into a through hole of an anchor plate in contact with an outer wall of a concrete body, and a PC steel stranded wire covered with a covering sheath is inserted into the water stop pipe. A PC steel stranded wire is sandwiched by a wedge that penetrates the end portion, the outer peripheral surface forms a conical surface, and is divided in the circumferential direction, and the wedge is fitted into the conical hole of the tightening sleeve. While the end abuts against the anchor plate, a closing sleeve is screwed into the outer end portion of the clamping sleeve, and a plurality of bolts penetrating the flange of the closing sleeve are screwed into the anchor plate. A rust-preventive material is filled into the gap between the fastening sleeve and the PC steel stranded wire from the injection hole provided in the shaft center, and then a cap is fitted into the injection hole and closed.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, an anchor plate is brought into contact with a side wall of a floor plate portion of a concrete bridge girder as a concrete body, an outer end of a steel or resin water stop pipe is brought into contact with an inner surface of the anchor plate, and a PC steel twist having a covering sheath peeled off. The end of the wire passes through the water stop pipe and the anchor plate and is sandwiched between the wedges. In other words, for the PC steel wire strands in the transverse direction that are pre-arranged on the floor plate portion of the concrete bridge girder, the ends of the PC steel wire strands are sandwiched by two or three divided wedges as fixing tools, and the wedges are Fit into the conical hole of the tightening sleeve and tighten.
[0007]
Next, a cup-type steel closing sleeve is screwed onto the end of the clamping sleeve, and a plurality of bolts inserted into the through holes of the flange of the closing sleeve are attached to the side wall of the concrete body so that the closing sleeve does not loosen. And screwed into a steel anchor plate that is in contact with Furthermore, after injecting an adhesive such as epoxy resin from the injection hole in the shaft center of the closing sleeve into the gap between the PC steel strand and the wedge, the cap is fitted into the injection hole and closed.
[0008]
On the other hand, the inner end of the water stop pipe and the sheath of the PC steel stranded wire are covered with an adhesive, and concrete is cast and embedded in the concrete body. After the concrete is hardened, a tensile force is applied to the other end of the PC steel stranded wire by hydraulic jacking, and it is sandwiched by another fixing tool and supported on the other side wall of the concrete body.
[0009]
【Example】
As shown in FIGS. 6 and 7, the concrete bridge girder 31 as a concrete body has a closed cross section composed of a floor plate 32 constituting a road surface, a side wall 34 projecting downward from the floor plate 32, and a lower wall 35. A central wall 33 is provided at the center of the left and right sides of the inner space 36. In the floor plate 32, a large number of PC steel stranded wires 20 extending in the lateral direction in the upper and lower center portions are arranged at intervals in the longitudinal direction of the floor plate 32, and intersect the front, rear, left and right above the PC steel stranded wire 20. An upper rebar 37 composed of a longitudinal rebar 37b and a lateral rebar 37a is disposed, and similarly, a longitudinal rebar and a transverse rebar that intersect in the front-rear and left-right directions also below the PC steel stranded wire 20. A lower reinforcing bar 38 is provided.
[0010]
As shown in FIG. 7, a large number of PC steel stranded wires 20 arranged in the transverse direction are arranged at intervals of 50 to 100 cm in the longitudinal direction, but the ends of some PC steel stranded wires 20 are arranged. The fixed-side fixing tool A may be embedded in the concrete. However, usually, the fixing side fixing tool A of the PC steel stranded wire 20 is disposed on one side wall of the concrete bridge girder 31, and after the concrete is hardened, as shown in FIGS. In order to apply a tension to the other end portion of the steel plate by a known hydraulic jack and maintain the tension state, a fastening side fixing tool B similar to the fixing side fixing tool A is brought into contact with the other side wall of the concrete body. Preferably, the fixed-side fixing tool A is previously attached to the PC steel stranded wire 20 at the factory, carried into the construction site, and disposed inside the mold before placing concrete. In this case, the PC steel stranded wire 20 is temporarily fixed at both ends, and the intermediate portion is disposed in a state where the intermediate portion is somewhat slacked downward, and when tension is applied to the PC steel stranded wire 20, It is preferable to apply a force that pushes up the central portion.
[0011]
As shown in FIGS. 4 and 5, the PC steel stranded wire 20 is formed by winding nine strands 22 having a small diameter around a central core wire 21 in a spiral shape, and having a larger diameter than the strand 22 outside the strand 22. These nine strands 23 are spirally wound. A gap between the core wire 21 of the PC steel stranded wire 20 and each of the strands 22 and 23 is filled with an adhesive such as an epoxy resin and covered with a cylindrical covering sheath 25 made of a synthetic resin. The covering sheath 25 is provided with a pair of axial protrusions 28 in order to suppress twisting and increase the familiarity with the concrete, and the thick annular protrusions 27 are spaced apart in the longitudinal direction. The thin annular grooves 26 are alternately formed.
[0012]
The present invention provides a fixing-side fixing tool A for fixing the end portion of the PC steel stranded wire 20 having the above-described covering sheath 25 to the side wall 34 of the concrete body. As shown in FIG. 1, the steel anchor plate 10 is applied to the side wall surface of the floor plate 32, and the end portion of the PC steel stranded wire 20 protrudes to the outside through the through hole 12 of the anchor plate 10. In order to give pretension to the PC steel stranded wire 20, the sheath sheath 25 is not inserted into the water stop pipe 14 penetrating the through hole 12 of the anchor plate 10, and the portion where the sheath sheath 25 is peeled off is formed on the inner surface of the anchor plate 10. It is inserted into the water stop pipe 14 that has come into contact. The connection portion between the inner end of the water stop tube 14 and the covering sheath 25 is covered with an adhesive such as an epoxy resin, and preferably wrapped with an adhesive tape so that water from the concrete body does not enter the PC steel stranded wire 20. Covered with. That is, the water stop pipe 14 covers the PC steel stranded wire 20 and protrudes into the through-hole 12 and comes into contact with the end face of the fastening sleeve 7 of the fixing tool A or to the cylindrical portion of the fastening sleeve 7. Slightly fitted. The PC steel stranded wire 20 from which the covering sheath 25 has been peeled is sandwiched between the cylindrical surfaces 8b of the wedges 8 having a semicircular cross section.
[0013]
As shown in FIGS. 1 to 3, the outer peripheral surface of the wedge 8 forms a conical surface 8 a, and an axial slit 8 c is provided at the circumferential center of the thick portion on the outer end side so that a pair of wedges 8 are twisted with PC steel. It is comprised so that the wire 20 may be clamped firmly. Preferably, the cylindrical surface 8b is provided with unevenness. In the illustrated embodiment, the wedge 8 is composed of two parts, but may be composed of three parts.
[0014]
The wedge 8 sandwiching the PC steel stranded wire 20 is inserted into the conical hole 7 a of the fastening sleeve 7. If a tensile force (rightward tension in FIG. 1) is applied to the PC steel stranded wire 20 in advance at the factory, the wedge 8 is drawn into the conical hole 7a and is firmly held by the tightening sleeve 7. The closing sleeve 2 having the screw hole 6 is screwed into the screw portion on the outer end side of the tightening sleeve 7. The closing sleeve 2 is provided with a cylindrical portion 5 covering the PC steel stranded wire 20 on the outer end side of the screw hole 6 and an injection hole 4 for injecting a rust preventive agent. After filling the inside of the PC steel stranded wire 20 from the injection hole 4 with a rust inhibitor, the injection hole 4 is closed by fitting a cap (not shown). Further, the bolts 15 are inserted into a plurality of through holes 3 a provided at equal intervals in the circumferential direction in the flange 3 of the closing sleeve 2, and the tips of the bolts 15 are screwed into the screw holes 13 of the anchor plate 10. Thus, the wedge 8 that sandwiches the PC steel strand 20 and the fastening sleeve 7 that engages the wedge 8 are covered with the closing sleeve 2, and a plurality of bolts 15 that pass through the closing sleeve 2 are screw holes of the anchor plate 10. 13, and the end of the PC steel stranded wire 20 is covered in a watertight manner. The anchor plate 10 is pressed against the inner end surface of the fastening sleeve 7 by a bolt 15. The water stop pipe 14 covering the PC steel stranded wire 20 and the covering sheath 25 is also pressed against the end wall surface of the fastening sleeve 7 through the through hole 12 or fitted into the cylindrical portion of the fastening sleeve 7. The inner ends of the water stop pipe 14 are bonded to each other by an adhesive and further covered with a resinous tape.
[0015]
As described above, the anchor plate 10 is applied to the side wall surface of the concrete body at the bridge construction site, that is, in contact with the side wall surface of the floor plate 32, and after the concrete is driven and solidified, the PC steel twist The other end of the wire 20 is clamped by the same fixing tool B and is applied to the other side wall surface of the floor plate 32, and a pretension is applied to the PC steel stranded wire 20 by hydraulic jacking.
[0016]
The axial ridge 28 of the covering sheath 25 prevents the covering sheath 25 from being twisted inside the concrete. The slit 8c of the wedge 8 gives a smooth clamping force to the PC steel stranded wire 20 when the wedge 8 is pushed into the conical hole 7a of the fastening sleeve 7.
[0017]
【The invention's effect】
In the present invention, as described above, a water stop pipe is inserted into the through hole of the anchor plate in contact with the outer wall of the concrete body, and the end of the PC steel stranded wire covered with the sheath is inserted into the water stop pipe. The PC steel stranded wire is clamped by a wedge whose outer peripheral surface forms a conical surface and is divided in the circumferential direction, the wedge is fitted into the conical hole of the fastening sleeve, and the inner end of the fastening sleeve is connected to the anchor plate The closure sleeve is screwed to the outer end of the clamping sleeve, and a plurality of bolts that penetrate the flange of the closure sleeve are screwed to the anchor plate, and are provided at the shaft center of the closure sleeve. After filling the gap between the fastening sleeve and the PC steel stranded wire from the injection hole with a rust preventive material, the cap is fitted into the injection hole and closed, so the PC steel stranded wire is pretensioned. Is added and exposed from the concrete body to the outside End of the C steel strands are maintained so as not rust.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view of a PC steel stranded wire fixing device according to the present invention.
FIG. 2 is a front sectional view of a wedge in the fixing device for the PC steel stranded wire.
FIG. 3 is a side sectional view of the wedge.
FIG. 4 is a side view of a PC steel stranded wire provided with a covering sheath in the fixing device for the PC steel stranded wire.
FIG. 5 is a front sectional view of the PC steel stranded wire.
FIG. 6 is a front sectional view of a concrete bridge girder in which PC steel stranded wires are arranged using the fixing tool according to the present invention.
FIG. 7 is a plan sectional view of the concrete bridge girder.
[Explanation of symbols]
A: Fixed side fixing tool B: Tightening side fixing tool 2: Closing sleeve 3: Flange 3a: Through hole 4: Injection hole 5: Cylindrical portion 6: Screw hole 7: Fastening sleeve 7a: Conical hole 8: Wedge 8a: Conical surface 8b: Cylindrical surface 8c: Slitting 10: Anchor plate 12: Through hole 13: Screw hole 14: Water stop tube 15: Bolt 20: PC steel stranded wire 20a: End portion 21: Core wire 22: Wire 23: Wire 25: Covering sheath 26: Annular groove 27: Annular ridge 28: Axial ridge 31: Bridge girder 32: Floor plate 33: Central wall 34: Side wall 35: Lower wall 36: Inner space 37: Upper rebar 37a: Lateral rebar 37b: Longitudinal reinforcing bar 38: Lower reinforcing bar

Claims (2)

A water stop pipe is inserted into the through hole of the anchor plate that is in contact with the outer wall of the concrete body, penetrates the end of the PC steel stranded wire covered with a sheath sheath, and the outer peripheral surface forms a conical surface. Further, a PC steel stranded wire is sandwiched by wedges divided in the circumferential direction, the wedge is fitted into the conical hole of the fastening sleeve, and the inner end of the fastening sleeve abuts against the anchor plate, while the fastening A closing sleeve is screwed to the outer end of the sleeve, and a plurality of bolts penetrating through the flange of the closing sleeve are screwed to the anchor plate, and the fastening sleeve is inserted from an injection hole provided in an axis of the closing sleeve. A PC steel stranded wire fixing tool, wherein a rust preventive material is filled in a gap between the PC steel stranded wire and a cap is fitted into the injection hole and then closed. The fixing tool for PC steel stranded wire according to claim 1, wherein an inner end portion of the water stop pipe and a covering sheath are covered with an adhesive.

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