JP4212957B2 - Grout injection method combined with vacuum pump at outer cable fixing part of PC bridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grout injection method using a vacuum pump in an outer cable fixing part of a prestressed concrete (PC) bridge.
[0002]
More specifically, after prestressing the structure by a post-tension method by tensioning the PC steel material penetrating through a series of sheaths to form a prestressed concrete structure (hereinafter also referred to as a PC structure), The present invention relates to a method for injecting and filling grout into a sheath.
[0003]
[Prior art]
The PC bridge is a structural bridge that is pre-stressed into the concrete frame with PC steel to increase the performance of concrete, which is relatively weak in tensile strength and strong in compressive strength. .
[0004]
In this pre-stress structure, especially in the post-tension method and the external cable method, the PC steel material is inserted into the concrete housing in a predetermined section including the fixing portion. Anti-corrosion paint etc. are given outside.
[0005]
The conventional example will be described with reference to FIGS. 4, 5 (a) and 5 (b). Each figure shows an external cable type and post tension type continuous PC version girder bridge. A web 3 having a bulging portion 9 at the lower portion is usually formed by placing concrete, and an end portion of the plate girder 1 is supported by a fulcrum 4 and an intermediate portion is supported by an intermediate fulcrum 5. An intermediate partition wall 6 also serving as a deviator (deflecting plate) is disposed between the adjacent webs 3 at a portion near the center of the interstaff of the plate girder 1, and at the intermediate fulcrum 5, the deviator ( An intermediate fulcrum cross beam 7 also serving as a deflection plate is provided.
[0006]
The PC steel material 8 is provided to extend in the bridge axis direction while being displaced up and down the neutral axis as shown in the figure, and the PC steel material end (left end in FIG. 4) is fixed to the fixing portion 11 at the upper part of the end cross beam 10. It has been established at. Further, the PC steel material 8 is disposed at the lower end portion of the intermediate partition wall 6 through the guide portion 12 at the intermediate portion between the fulcrum 4 and the intermediate fulcrum 5. Therefore, the PC steel material 8 is disposed at a position away from the neutral shaft (the center portion in the vertical direction of the girder) in the center portion of the span.
[0007]
The PC steel material 8 further extending from the intermediate partition wall 6 is inserted through an insertion hole 13 formed in the upper portion of the intermediate fulcrum cross beam 7 also serving as a devitater (deflection plate) provided at the intermediate fulcrum 5, and the bridge center (right side in FIG. 4). ) Extending toward the lower portion of the next intermediate partition wall 6a.
[0008]
In the bridge structure of the PC (or PRC) plate girder type in which the PC steel material 8 is arranged, the end portion of the PC steel material 8 is housed in the sheath 14 and the end cross beam 10 or the intermediate fulcrum cross beam. 7 (hereinafter, referred to as fixing unit concrete 15) is fixed by fixing device 11.
[0009]
The fixing device 11 shown in FIGS. 6 and 7 will be described. A plastic sheath 14 having a predetermined length is connected by a plastic joint sheath 17 at a connection portion (joint portion) 16, and the connection portion 16 between the sheath 14 and the joint sheath 17. The vinyl tape 18 is wound so as to seal the gap between them, and these are arranged inside the fixing portion concrete 15. In the post-tension type bridge structure, the sheaths 14 and 17 through which the PC steel material 8 is inserted are arranged inside the mold forming the bridge structure, and concrete is placed with the ends of the sheath positioned outside the mold. To form.
[0010]
At the left end of FIG. 6, a fixing portion 11 a for the PC steel material 8 is provided at the end of the plastic sheath 17. The fixing portion 11a includes an anchor head 20 disposed at an outer end portion of an anchor plate 19 whose tip is fitted to a plastic sheath 17, and a male and female cone member (not shown) placed outside the anchor head 20. It is configured through.
[0011]
The PC steel material 8 is pulled out from the ends of the plastic sheaths 14 and 17 and pulled out through the anchor head 20, and the PC steel material 8 is tensioned with jacks at both ends. A state in which prestress is introduced is maintained by the female cone. In addition, the extra length part of PC steel material 8 which protrudes from the anchor head 20 is cut | disconnected. Further, an extra length protection cap 22 having a grout injection hole 21 is attached to the anchor head 20.
[0012]
A hose led out from the discharge port of the grout pump 23 is connected to the grout injection hole 21 of the extra length protection cap 22 via an on-off valve 26, and each sheath 17 is passed through the grout hole 24 of the anchor head 20 from the grout injection hole 21. , 14 is filled with grout 25. The tip on which the sheath 14 is installed is a little protruding from the range where the fixing part concrete 15 is constructed. That is, the sheath end portion 14a stops near the outside of the fixing portion concrete 15, and the PC steel material 8 is exposed from the sheath end portion 14a.
[0013]
When filling the grout 25 into the sheaths 17 and 14 at the end portion of the PC steel material 8, the grout 25 that is press-fitted from the fixing portion 11a side leaks from the sheath tip side when the sheath end portion 14a is opened, The sheath cannot be filled. For this reason, the sheath end portion 14a is closed by winding the heat-shrinkable plastic tape 26 or the like, and the clearance between the PC steel material 8 is reduced as much as possible. However, it is inevitable that the grout 25 that is press-fitted with high pressure from the fixing portion 11a side leaks from the gap of the sheath end portion 14a.
[0014]
The purpose of injecting and filling the grout 25 in the sheaths 14 and 17 is to protect the PC steel material 8 inserted into the sheath from corrosion, and to integrate the PC steel material 8 and concrete via a sheath (duct). Maintaining the performance and durability of the object is to completely eliminate the air and water in the sheath and fill the sheath with grout.
[0015]
In order to smoothly inject the grout into the sheath, a method of filling the grout over the entire length of the long sheath by pressurizing one end side of the sheath and sucking the other end to depressurize the sheath is conventionally known. It is.
[0016]
For example, in Japanese Patent Laid-Open No. 4-41867 (prior art 1), an intake pump is connected to a grout discharge port at one end of a sheath embedded in a concrete member, and an intake pump is connected to a grout discharge port at the other end. A method is disclosed in which a pump is connected, a grout supply source is connected to the grout inlet on the other end side, the air in the sheath is decompressed by the intake pump, and the grout material is sucked and filled in the sheath.
[0017]
In Japanese Patent No. 2757134 (conventional example 2), air in the sheath is evacuated from one end of the sheath closed at both ends, and then grout is injected into the sheath from the one end using the vacuum. A method is disclosed.
[0018]
Further, according to Japanese Patent Laid-Open No. 2002-309777 (Prior Art 3), the vacuum pump is continuously operated to depressurize the inside of the sheath, and the grout pump is operated only under a vacuum state in which the atmospheric pressure in the sheath is equal to or lower than the set negative pressure. It is known to fill the grout in the entire cross section in the sheath so as to reliably fill it, regardless of how long the sheath is, by filling it repeatedly.
[0019]
[Patent Document 1]
JP-A-4-41867 [Patent Document 2]
Japanese Patent No. 2757134 [Patent Document 3]
Japanese Patent Laid-Open No. 2002-309777 [0020]
[Problems to be solved by the invention]
The anchoring part of the prestressed concrete bridge must have a structure that can smoothly transmit the tension to the main girder concrete, so the anchoring part of the outer cable has an inner / outer double pipe structure that can be replaced in the future (this inner / outer duplex structure). Regarding the tube structure, an embodiment of the present invention will be described later). In this case, the inside sheath becomes narrow, and a structure that partially grouts in the narrow space between the PC steel materials accommodated in the narrow space portion (referred to as a partial grout structure). Further, the inner sheath, is constructed by connecting a plurality of split sheath, stop by the connecting portion and the split sheath, etc. gap between PC steel inner sheath tip that closes easily with foamed urethane or vinyl tape Generally, the water part is used. In such a simple water stop method, construction is easy, but the pressure resistance is inferior, and it is expected that the grout leaks from the water stop portion when the grout is injected. For this reason, when filling grout in an inner sheath at high pressure, the problem that a grout leaks from each said water stop part is a reality.
[0021]
Cause of grout leakage are various, but (1) for water stop portion is a simplified way to stop in foamed urethane or vinyl tape, it can not tolerate large pressure. (2) It is assumed that the grouting pressure cannot be raised because the curing of the water stop portion is weak. Then, when the grout is leaking from the water shut-off part, a problem of workability and filling of (quality) occurs, and Tsu had with or so, it can not be carried out smoothly injection and reduce the grout injection pressure.
[0022]
The present invention has been proposed in view of the above problems, and in the bridge structure in which the PC steel material is disposed by the post-tension method and the external cable method, the connection portion and the tip portion of the inner sheath are similar to the conventional ones. construction regardless of performing an easy simple water stopping structure (i.e. grout leakage prevention structure for blocking easily with foamed urethane or vinyl tape), provide a method for avoiding leakage from smooth filling a sheath into the sheath The purpose is to do.
[0023]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
[0024]
According to a first aspect of the present invention, an outer sheath is embedded in an inner / outer double sheath that penetrates through both end surfaces of a fixing portion concrete having a predetermined thickness, which is a cross beam of a PC bridge, and the PC steel material is inserted, and the PC steel material is embedded in the outer sheath. The inner sheath is inserted, and one end portion of the inner and outer double sheaths is inserted through an anchor plate disposed on one end surface of the fixing portion concrete, and the anchor is installed in the extra length protective cap coupled to the anchor plate. The PC steel material fixed on the plate and led out from the other end of the inner sheath is a PC steel material of a predetermined length constituting the grout injection jig and a grout stopper spacer housed inside one end of the tube body. an insertion hole inserted, after having connected the pipe body to the distal end of the inner sheath, with a vacuum pump connected to the grout discharge port provided in the vicinity of the grout stop spacer While sucking the inside of the side sheath, and wherein the press-fitting the grout into said inner sheath from the injection port of the extra length protective cap.
[0025]
According to a second invention, in the first invention, the inner sheath is composed of a plurality of split sheath members, a connecting portion between the split sheaths, a tip of the inner sheath, and a tube of a predetermined length constituting a grout injection jig. The connection portion is a simple connection structure in which a water stop member is wound and connected to each other, and the gap between the other end of the tube and the PC steel material is a closed structure by foaming urethane. .
[0026]
[Action]
According to the present invention, the grout is press-fitted into the inner sheath from the injection port of the extra length protection cap while sucking the inside of the inner sheath using a vacuum pump connected to the grout discharge port provided in the vicinity of the grout stopper spacer. it makes it possible implantation at low grouting pressure, closed connecting portion and the split sheath in and out each sheath a waterproof part of the gap of the sheath and PC steel, in a conventional manner simply by foamed urethane or vinyl tape Even when the grouting is carried out, there is no possibility that the grouting leaks out from the water stop portion, and the grouting can be surely performed.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0028]
1 to 3 show an embodiment of the present invention, FIG. 1 is a sectional view of a fixing device, FIG. 2 is an enlarged view of FIG. 1, and FIGS. 3 (a) and 3 (b) are views of the anchor head of FIG. It is a front view and sectional drawing.
[0029]
1 and 2 show a post-tension type, PC cable girder with an external cable system, and penetrates from one end surface 15a to the other end surface 15b of an end cross girder or intermediate cross girder (hereinafter referred to as fixing unit concrete) 15. A plurality of PC steel materials 8 are inserted through a sheath (described later), the PC steel material 8 is fixed by the fixing device 11 on one end surface 15a of the fixing portion concrete 15, and the PC steel material 8 is fixed on the other end surface 15b. The mode which is exposed from a series of sheaths and is extended in the other end direction in a PC version girder bridge is shown.
[0030]
Since the fixing portion of the PC steel material 8 in the outer cable system must have a structure that can smoothly transmit the tension force to the main girder concrete, the fixing portion of the PC steel material 8 has an inner / outer double pipe structure that can be replaced in the future. . For this reason, the inner sheath 28 and the outer sheath 29 are disposed so as to penetrate through the fixing portion concrete 15 and open at both end faces 15a and 15b.
[0031]
The outer sheath 29 includes a trumpet-shaped outer joint sheath (hereinafter referred to as an outer first divided sheath) 29a having an enlarged diameter on one end side, a different-diameter joint 40 on the reduced diameter side thereof, and an outer side thereof. and a connected (hereinafter referred to as the outer second split sheath) outer split sheath and 29 b by winding attaching taping (not shown).
[0032]
The inner sheath 28 includes a trumpet-shaped inner joint sheath (hereinafter referred to as an inner first divided sheath) 28a having an enlarged diameter at one end side, and an inner divided sheath that is fitted and connected to the reduced diameter side of the inner sheath 28 via a rubber ring 42. (Hereinafter referred to as the inner second divided sheath) 28b. The inner first divided sheath 28a is accommodated in the outer first divided sheath 29a, and the inner second divided sheath 28b is accommodated in the outer second divided sheath 29b. Each of the one end portions 29d and 28d (the right end portion in the figure) of the outer first divided sheath 29a and the inner first divided sheath 28a protrudes from the other end surface 15b (the right side in the figure) of the fixing portion concrete 15, And the one end part 28d of the inner side 2nd division | segmentation sheath 28b protrudes longer than the one end part 29d of the outer side 2nd division | segmentation sheath 29b. On the outer periphery of the outer first divided sheath 29a, a spiral line 43 for reinforcement is embedded in the concrete.
An anchor plate 30 is embedded in one end surface 15a (left side in the figure) of the fixing portion concrete 15 so that the outer surface of the anchor plate 30 and the one end surface 15a of the fixing portion concrete 15 are aligned. The trumpet-shaped outer first divided sheath 29a whose outer end side has an enlarged diameter and the enlarged diameter side ends 28c and 29c of the inner first divided sheath 28a have substantially the same diameter and are closely joined. The diameter-expanded side ends 28c and 29c of the inner and outer sheaths 28 and 29 are inserted into the hole 31 of the anchor plate 30 and bent outward on the outer surface side, and then fixed to the outer surface of the anchor plate 30 with screws 32. Has been.
[0034]
Further, an anchor head 33 is disposed on the outer surface of the anchor plate 30, and the end portions 8 a of the PC steel material 8 are inserted into the plurality of female cone members 34 disposed on the anchor head 33, and then the end of the PC steel material 8 is inserted. The portion is tensioned with a jack to introduce prestress, and the end portion of the PC steel material 8 is fixed by the male cone member 35. The extra length portion of the PC steel material 8 protruding from the anchor head 33 is cut. In FIG. 3, the anchor plate 30 is provided with a PC steel material hole 41 and a sleeve 41 a communicating with the female cone member 34, and further with a grout hole 44.
[0035]
An extra length protective cap 37 having a grout inlet 36 is placed on the outer side of the anchor head 33, and the base end portion of the cap 37 is fixed to the outer surface of the anchor plate 30. Grout 38 is filled in the extra length protection cap 37 and the inner sheath 28.
[0036]
The reason why the PC steel material 8 is made into the inner and outer double sheaths 28 and 29 and is inserted through the inside is to allow the PC steel material 8 to be replaced after the concrete structure is constructed. That is, when the PC steel material 8 is replaced, it is possible to leave the outer sheath 29 in the fixing portion concrete 15 and completely replace the PC steel material 8 filled with the grout 38 and the inner sheath 28. The inner and outer sheaths 28 and 29 are configured to be easily separated from each other by pulling out the inner sheath 28 through a slight gap and outwardly. The outer sheath 29 is embedded in the concrete by placing it at a predetermined site and placing the fixing portion concrete 15 with a mold.
[0037]
A process of filling the grout 38 in the inner sheath 28 will be described. First, a hose led out from the outlet of the grout pump is connected to the grout inlet 36 of the extra length protection cap 37 (not shown), and the inside of the inner sheath 28 is passed through the grout 44 (shown in FIG. 3) of the anchor head 33. Is filled with grout 38.
[0038]
At this time, since the distal end portion 28d of the inner sheath 28 is opened, in this state, the inner sheath 28 cannot be filled from the inner sheath distal end opening 45. Therefore, in the present invention, a grout injection jig 46 for preventing grout leakage is connected to the inner sheath distal end portion 28d.
[0039]
The grout injection jig 46 includes a plastic tube 47 such as a polyethylene tube having a predetermined length (L), a grout stopper spacer 48 housed inside one end of the tube 47, and a grout stopper spacer 48. In the vicinity (that is, in the vicinity of the intermediate portion of the tube body 47), a grout discharge port 49 is provided so as to protrude outside the tube body 47. A discharge hose 50 is connected to the grout discharge port 49, and a vacuum pump (not shown) is connected to the discharge hose 50.
[0040]
The grout stopper spacer 48 is disc-shaped, and a PC steel material insertion hole 51 is opened through the plate thickness portion. The PC steel material 8 is inserted through the PC steel material insertion hole 51 and extends further from the tube body 47 further forward.
[0041]
One end 47a of the tube 47 of the grout injection jig 46 is slightly covered with the inner sheath distal end portion 28d at the preparation stage of the grout injection operation, and a simple water-stop member 52 such as a heat-shrinkable plastic tape is wound around the overlapping portion. . Furthermore, since there is a gap between the PC steel material insertion hole 51 of the grout stop spacer 48 and the PC steel material 8, there is a possibility that the grout leaks from there. Thus through the foamed urethane is also the distal end of tube 47 wound simple water-shutoff member 53 such as heat shrinkable plastic tape is subjected to a leakage means grout easily.
[0042]
After the preparation for the grouting operation is thus completed, the grouting nozzle is set in the grouting port 36 of the extra length protection cap 37 (left side of the figure), and the discharge discharged from the grouting port 49 of the grouting jig 46 is performed. A hose 50 is connected to a vacuum pump (not shown) and set.
[0043]
In the grouting operation, first, the switching valve (not shown) of the grouting port 36 is closed, the vacuum pump is operated, and the inside sheath is evacuated through the grouting port 49. At this time, the atmospheric pressure inside the sheath is set to about −0.09 MPa (−0.09 kgf / cm ² ). When the air pressure inside the sheath is secured to about -0.09 MPa (-0.09 kgf / cm ² ), the switching valve of the grout inlet 36 is opened and grout injection is started.
[0044]
At this time, the injection operation is performed at a grout injection rate of 10 liters / minute or less. When grout appears from the discharge hose 50 connected to the grout discharge port 49 communicating with the inner sheath 28, a three-branch valve (not shown) installed in the grout discharge port 50 is switched so that the grout 38 does not enter the vacuum pump. Discharge to a predetermined discharge grout storage container (not shown).
[0045]
Thus, in the present invention, the grout outlet 50 is provided in the vicinity of the front end of the filling range in the range where the end portion 8a of the PC steel material 8 covers the inner and outer sheaths 28 and 29 (that is, the partial grout filling range). Since the inside of the inner sheath 28 is sucked and depressurized, the grout can be filled from the grout inlet 36 with a relatively low pressure.
[0046]
Therefore, the connecting portion between the inner sheath distal end 28d and the tube end 47a of the grout injection jig 46 and the gap between the tube other end 47b ahead of the grout stopper spacer 48 and the PC steel material 8 are heat-shrinkable plastic. despite only by the water stop by a simple water-shutoff members 52 and 53 such as a tape or foamed urethane, grout 38 is not leaking from the water stop portion, therefore, smoothly filling the grout 38 in the inner sheath 28 It becomes possible.
[0047]
Note that it is within the scope of the present invention to appropriately change the design of the configuration shown in the embodiment.
[0048]
【The invention's effect】
According to the present invention, the grout is press-fitted into the inner sheath from the injection port of the extra length protection cap while sucking the inside of the inner sheath using a vacuum pump connected to the grout discharge port provided in the vicinity of the grout stopper spacer. it makes it possible implantation at low grouting pressure, closed connecting portion and the split sheath in and out each sheath a waterproof part of the gap of the sheath and PC steel, in a conventional manner simply by foamed urethane or vinyl tape Even when the grouting is carried out, there is no possibility that the grouting leaks out from the water stop portion, and the grouting can be surely performed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a fixing portion of a PC steel material in a PC bridge or the like according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a fixing portion of the PC steel material of FIG.
3A and 3B are a front view and a cross-sectional view of the anchor head in FIG. 1, respectively.
FIG. 4 is a cross-sectional side view of a conventional PC cable girder bridge using a conventional external cable system and a post tension system.
5A and 5B are enlarged cross-sectional views taken along lines AA and BB in FIG.
FIG. 6 is a side view of a conventional fixing device.
FIG. 7 is an enlarged cross-sectional view of the fixing device shown in FIG.
1 plate girder 2 upper floor plate 3 web 4 fulcrum 5 intermediate fulcrum 6 intermediate partition wall 6a intermediate partition wall 7 intermediate fulcrum cross beam 8 PC steel 8a PC steel end 9 bulging part 10 end cross girder 11 fixing device 11a fixing part 12 guide Part 13 Insertion hole 14 Sheath 14a Sheath end 15 Fixing part concrete 15a One end face 15b Other end face 16 Connection part 17 Joint sheath 18 Vinyl tape 19 Anchor plate 20 Anchor head 21 Grout injection hole 22 Extra length protection cap 23 Grout pump 24 Grout hole 25 Grout 26 On-off valve 26 Heat-shrinkable plastic tube 27 PC steel material insertion hole 28 Inner sheath 28a Inner first divided sheath 28b Inner second divided sheath 28c Expanded side end 28d Inner sheath tip 29 Outer sheath 29a Outer first divided Sheath 29b Outside second divided sheath 29c Diameter expansion End 29d Outer sheath distal end 30 Anchor plate 31 Hole 32 Screw 33 Anchor head 34 Female cone member 35 Male cone member 36 Grout inlet 37 Extra length protection cap 38 Grout 40 Different diameter joint 41 PC steel hole 41a Sleeve 42 Rubber ring 43 Spiral muscle 44 Grout hole 45 Inner sheath tip opening 46 Grout injection jig 47 Tube 47a Tube end 47b Tube end 48 Grout stop spacer 49 Grout outlet 50 Drain hose 51 PC steel material insertion Hole 52 Simple water stop member 53 Simple water stop member

Claims (2)

An outer sheath is embedded in the inner and outer double sheaths through which the PC steel material is inserted, penetrating through both end surfaces of the fixed part concrete having a predetermined thickness, which is a cross beam of the PC bridge, and an inner sheath through which the PC steel material is inserted into the outer sheath. One end of the inner and outer double sheaths is inserted through the anchor plate disposed on one end surface of the fixing portion concrete, and then fixed to the anchor plate in the extra length protection cap coupled to the anchor plate. The PC steel material led out from the other end of the sheath is inserted through the PC steel material insertion hole of the grout stopper spacer housed inside one end of the tube body and the predetermined length constituting the grout injection jig, after having connected the pipe body to the distal end of the inner sheath, the inner sheath with a vacuum pump connected to the grout discharge port provided in the vicinity of the grout stop spacer Pull while the vacuum pump combination grout grouting in the outer cable fixing portion of the PC bridge, characterized in that press-fitting the grout into the inner sheath from the injection port of the extra length protective cap. The inner sheath is composed of a plurality of split sheath members, and a water stop member is wound around a connection portion between the split sheaths and a connection portion of a predetermined length of the tubular body constituting the tip of the inner sheath and the grout injection jig. a simple connection structure they are connected, also, the outer cable fixing of PC bridge according to claim 1, wherein the the gap between the other end and the PC steel pipe is a closed structure by foamed urethane Grout injection method combined with vacuum pump in the section.

Images