JP4455370B2 - PC roof girder and under-base crossing structure using the PC roof girder - Google Patents

Description

The present invention relates to a prestressed concrete roof girder (hereinafter referred to as a PC roof girder) and a subbase crossing structure using the PC roof girder.

  A base that can be adjusted in height to a start shaft that is temporarily installed on the side of the ground structure when building underground structures (also referred to as under-roadbed crossing structures) that cross these under the railway, road, or existing building. The propelling machine is installed via the PC roof girder having a hollow portion disposed at the front thereof, and the PC roof girder is mounted in a state in which the screw auger is fitted into the hollow portion. Then, the excavator is operated while excavating with a screw auger, and a PC roof girder is press-fitted from the starting vertical shaft side to the reaching vertical shaft, and at the same time, the joint hardware provided on the PC roof beam is inserted between adjacent PC roof beams. There is known a construction method in which a wall to be a ceiling portion, a floor portion, or a side portion of an underground structure is formed by engaging with each other, and the underground structure is constructed by excavating and discharging the inside thereof. In addition, the square steel pipe (leading pipe) is advanced ahead until it reaches the arrival shaft from the start shaft while excavating the inside, and then the square steel tube is pushed ahead by pushing the PC roof girder while pushing out the square steel pipe from the arrival shaft. There is a post-propulsion replacement method.

  7 and 8 show examples in which an underground structure having a frame-shaped square cross section is constructed. In this subbase crossing structure 1, a plurality of PC roof girders 3 extending in the front-rear direction constituting the wall of the ceiling portion 2, and a plurality of PC roof girders 3 constituting the floor portion 4 extending in the front-rear direction are provided. A hollow corner steel box girder 5 is arranged at each intersection (corner of the square wall) of the plurality of PC roof girders 3 extending in the front-rear direction constituting the side wall 9, The sheath 19 provided in the PC roof girder 3 extends over the side plate 6 provided on the side facing the PC roof girder 3 in the corner steel box girder 5 and the fixing bracket 7 disposed on the inner surface of the side plate 6. PC steel materials 8 and 10 are laterally tightened and tightened horizontally. Further, reinforcing steel bars (not shown) are arranged inside the corner steel box girder 5 and hardened with time in the corner steel box girder 5. A roadbed crossing structure 1 is configured by filling the property material 11. In addition, L-shaped joint metal fittings 12 that are also used as guide fittings are provided on opposite side portions of each PC roof girder 3, and the PC roof girder 3 adjacent in the vertical direction or the horizontal direction is connected to the pair of fitting metal pieces 12 Are connected so that the adjacent PC roof girders 3 are not displaced. Further, the joint hardware 12 serves as a guide when the PC roof girder 3 is press-fitted. The joint portions of adjacent PC roof girders 3 are filled with a joint material 13 that is time-curable such as non-shrink mortar.

  Further, as shown in FIG. 8, when the span between the side wall portions 9 of the underground structure 1 having a quadrangular cross section is increased, the ceiling portion 2 and the floor portion 4 of the underground structure are placed between the PC roof girders 3 that are joined side by side in parallel. An intermediate wall (intermediate strut) 14 may be provided and built by supporting the vertical load of the ceiling portion 2 on the intermediate wall 14, but in this case, the portion of the hollow portion 16 of the PC roof girder 3 is weak in strength. Therefore, it is necessary to allocate the PC roof girder 3 of the ceiling portion 2 and the floor portion 4 so that the intermediate wall (intermediate column) 14 does not come into the hollow portion 16.

In other words, the PC roof girder 3, which is an element having a rectangular cross section, is used to propel the ground from the starting vertical shaft excavated to the side of the ground structure toward the final vertical shaft. while rejection to the rear is press-fitted by pressing after the PC roof digit 3. For this reason, as shown in FIG. 1 (b), the PC roof girder 3 is provided with one hollow portion 16 communicating with the longitudinal direction of the member at the center of the girder, and a pair of cross sections on opposite sides. An L-shaped joint metal fitting 12 is also provided.

  As described above, the PC roof girder press-in method includes the direct propulsion method and the propulsion replacement method after the square steel pipe leading. In the direct propulsion method, the PC roof girder 3 follows the rear portion of the front conduit having a hollow portion and is directly propelled. Further, in the propulsion and replacement method after the square steel pipe precedent, a plurality of square steel pipes are propelled in advance, and then the PC roof girder 3 is followed and propelled so as to replace the square steel pipe. A plurality of PC roof girders 3 are juxtaposed in parallel in the horizontal direction or the vertical direction by the above-mentioned construction methods, and the joint metal fittings 12 of the PC roof girders 3 are engaged with each other to form a rectangular cross-section wall as shown in FIG. A frame is constructed, and the inside of the subbase crossing structure 1 is constructed by excavating the inside of the frame. In addition, there exist patent documents 1-7 as this kind of prior art.

Japanese Patent Application Laid-Open No. 57-1000023 JP 61-95199 A Japanese Patent Laid-Open No. 62-117990 JP-A-1-102197 Japanese Patent Laid-Open No. 3-156095 JP-A-5-171888 JP-A-6-307183

  A conventional PC roof girder used when constructing a subbase crossing structure has a pair of fitting fittings also used as a pair of guide fittings on both sides of a rectangular cross-section PC roof girder body having one hollow portion (hollow void). It is an element (FIG. 1b), and this is constructed by the direct propulsion method or the propulsion replacement propulsion method after preceding the square steel pipe. This construction method does not damage the PC roof girder, press fits after digging, and engages with the adjacent PC roof girder that has been press-fitted in advance through a joint metal fitting also serving as a guide. Although it can be stably press-fitted by simply pushing it later, it does not require much labor during construction, but it has the following problems.

  That is, as shown in FIG. 7, when the span between the side walls in the cross-section under the roadbed with a square cross section becomes large, it is necessary to provide an intermediate wall (intermediate column) to support the PC roof girder on the ceiling. In this case, the portion of the hollow portion of the PC roof girder is weak in strength in the vertical direction, and is supported by the joint portion of the PC roof girder avoiding this portion of the hollow portion. However, it is difficult to assign the ceiling and floor PC roof girders so that the upper and lower end surfaces of the intermediate wall are located at the joints. For this reason, the conventional PC roof girders having one hollow part are not suitable. If used, it would be an uneconomical structural plan.

  In addition, because each PC roof girder with a single hollow part is press-fitted, it requires a large number of propulsion cycles and a large number of cycles for replacing a square steel pipe that was previously propelled to a PC roof girder. Therefore, improvement in the rationalization of these construction work has been desired.

  Therefore, the present invention has been developed as a method for solving the above-mentioned problems by creating a PC roof girder having a plurality of hollow portions and using this as one element, and using this PC roof girder as a rational method. It is possible to greatly shorten the PC roof girder propulsion cycle or the replacement construction cycle with the square steel pipe when constructing the structure under the subbase crossing structure and the propulsion replacement method after the square steel pipe preceding.

  In order to achieve the above object, the present invention is configured as follows.

The PC roof girder having a plurality of parallel hollow portions according to the first aspect of the invention is a prestressed concrete roof girder (hereinafter referred to as a PC roof girder) that is press-fitted so as to cross the roadbed base plate, and both sides of the PC roof girder body. In the PC roof girder having a pair of joint hardware in the part and having a hollow portion continuous in the longitudinal direction of the member of the PC roof girder body, the hollow portions communicating in the longitudinal direction of the member are parallel with a gap in the width direction. A plurality of hollow portions in the width direction have a single hollow portion and a guide roof joint metal fitting for engaging the joint hardware of the PC roof girder. It is the same distance in a state of being promoted PC roof girder in parallel with a joint hardware of the alternate, a PC roof girder with such a plurality of hollow portions, and between the hollow portion adjacent Septum, characterized in that there is a built-digit structural.

In the subbase crossing structure of the second aspect of the invention, the subbase crossing structure including a plurality of PC roof girders in the ceiling press-fitted so as to cross the base subbase and a plurality of PC roof girders in the floor portion. in the vertical direction of the end portion of the intermediate wall, the internal girder for structures in PC roof girder having a plurality of hollow portions in parallel to the first aspect of the present invention which is provided in the ceiling portion provided between at least a ceiling and a floor The PC roof girder having a plurality of parallel hollow portions of the first invention provided on the floor is provided so as to be interposed between the built-in girder for construction.

In the press-fitting method of the PC roof girder of the present application, it is a press-fitting method of the PC roof girder for constructing the above-mentioned subbase crossing structure, from the starting part while discharging the excavated sediment through the hollow portion of the square steel pipe. In the press-fitting method of a PC roof girder that press-fits the PC roof girder into the ground while pushing out the square steel pipe from the reaching part by pressing the PC roof girder following the square steel pipe after preceding press-fitting over a reaching part. The square steel pipes are sequentially pressed and placed in parallel from the starting part to the reaching part while discharging excavated sediment through each hollow part, and then arranged in parallel to the plurality of square steel pipes as described in the first invention. The PC roof girder having a plurality of hollow portions is followed, and the PC roof girder is press-fitted into the ground while simultaneously pushing out the plurality of rectangular steel pipes from the reaching portion by pressing the PC roof girder. And wherein the Rukoto.

The PC roof girder of the present invention has a structure in which a plurality of installed conventional PC roof girders are integrated in parallel, and a plurality of hollow portions communicating in the longitudinal direction of the member are provided in parallel at intervals in the width direction. The interval between the hollow portions in the width direction has one hollow portion and has the one hollow portion that is adjacent to the joint fitting of the PC roof girder having the joint metal fitting that also serves as a guide and also serves as a guide and joint. It is the same interval as the state in which the PC roof girders having hardware are propelled in parallel, and is a PC roof girder having a plurality of such hollow portions, and the partition wall between the adjacent hollow portions is a structure built-in girder and Since the width is widened, the intermediate wall (support) avoids the joint portion of the PC roof girder which is difficult to be allocated, and is separated from the partition wall portion of the hollow portion within the range in the width direction of the PC roof girder. Built for structure Can be allocated so that the upper and lower ends of the intermediate wall (support) are located at the site of the above, compared with the conventional PC roof girder having one hollow portion, the allocation work is easy and the construction work is streamlined, Economical structural planning can be achieved, and the strength of the subbase crossing structure is improved.

In the present invention, after a plurality of rectangular steel pipes are sequentially advanced in advance, the PC roof girder having a plurality of hollow portions is simultaneously pushed to push out the plurality of square steel pipes and extrude them from the reaching shaft side, so that the conventional PC roof Multiple digits can be replaced at a time, and the replacement construction cycle can be shortened to a fraction of that of the prior art. Furthermore, since the PC roof girder of the present invention corresponds to a plurality of conventional PC roof girders installed, at least one pair of fitting hardwares arranged on both sides of the girder is unnecessary, and the adjacent PC roof girder The joint work for treating the joint part can be almost halved and the construction process can be simplified. Furthermore, the formwork at the time of manufacturing the PC roof girder only needs to widen only the bottom plate, and the side frame can be diverted as before, which is also economical in this respect. In addition, this invention is applicable also to a subbase crossing structure without an intermediate wall (support | pillar).

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  The features of the present invention lie in the structure of a PC roof girder, a subbase crossing structure having an intermediate wall (intermediate strut) using the PC roof girder, and a method for press-fitting the PC roof girder into the ground.

  FIG. 1 (a) shows a PC roof girder 17 according to the present invention. The PC roof girder main body 17a has joint metal fittings 12 that also serve as a pair of L-shaped guide fittings on both sides of the PC roof girder main body 17a. Two hollow portions 16 communicating with each other in the longitudinal direction of the member 17a are provided in parallel with an interval, and a partition between the two adjacent hollow portions 16 is continuous in the longitudinal direction of the member, Has been. The built-in girder 20 is characterized in that it is a built-in girder that functions as a support wall for a structure that supports the intermediate wall (intermediate strut) of a subbase crossing structure having an intermediate wall (intermediate strut).

  The PC roof girder may be provided with three or more hollow portions. In this case, a plurality of built-in girders are formed between the plurality of hollow portions.

  2 and 3 show a subbase crossing structure 21 according to Embodiment 1 constructed using the PC roof girder 17 of the present invention. In this subbase crossing structure 21, a wall frame having a square cross section composed of a ceiling portion 23, a bottom portion 24, and a side wall portion 25 is constructed by a PC roof girder 17 having two hollow portions 16. An intermediate wall (intermediate column) 14 is provided between the ceiling portion 23 and the bottom portion 24 between the side wall portions 25. This intermediate wall (intermediate column) 14 is provided when the span between the side wall portions is relatively large and supports the load of the intermediate portion of the ceiling portion 23.

  The PC roof girder is generally provided with a hollow portion 16 so that a medium digging propulsion method using a screw auger can be applied. However, since the hollow portion 16 is weak in strength, conventionally, when the intermediate wall 14 is constructed in the subbase crossing structure 21, the position where the hollow portion 16 of the PC roof girder 3 is removed, that is, the adjacent PC roof girder. 3, so that the two PC roof girders 3 on both the left and right sides, which are single members, are easily displaced, and therefore the position of the seam portion 15 is In the conventional PC roof girder 3, it is difficult to assign each PC roof girder 3 in the left-right direction when the PC roof girder 3 is positioned while being positioned on the ceiling part 2 and the floor part 4.

  In the PC roof girder 17 according to the first embodiment of the present invention, the joint portion 15 formed between the plurality of hollow portions 16 is provided in the middle so as to avoid the joint portions 15 and the hollow portions 16 between the girders. By being positioned within the end surface of the wall 14, the strength of the PC roof girder 17 can be secured and the intermediate wall 14 can be joined. In addition, the wall thickness dimension can be made thin if the strength of the built-in girder 20 is high-strength concrete that exhibits a compressive support force equal to or greater than the strength of the intermediate wall 14. The PC roof girder 17 is made of precast prestressed concrete, and the PC steel material embedded in the member cross section is omitted.

  That is, since the built-in girder 20 is a part of the PC roof girder 17 that is a single member, the built-in girder 20 can be easily and reliably positioned within the end surface of the intermediate wall 14 by positioning the PC roof girder 17. it can. Therefore, in the first embodiment, it is easy to assign the PC roof beam 17 in the left-right direction while positioning the PC roof beam 17 on the ceiling 23 and the floor 24. Reference numeral 18 denotes a cast-in-place concrete block for adjusting the allocation. The joint portion 15 of the PC roof girder 17 is engaged with the joint hardware 12 that also serves as a pair of guide fittings, the joint portion 15 is filled with the joint material 13, and the ceiling portion 23, the side wall portion 25, and the floor portion 24 are provided. A corner steel box girder 5 is provided at the intersecting portion, and is joined by side-tightening PC steel materials 8 and 10, reinforcing steel bars are arranged in the corner steel box girder 5, and the time-hardening material 11 is filled. This is the same as before.

  FIG. 4 shows a subbase crossing structure 21a according to Embodiment 2 constructed using the PC roof girder 17 of the present invention. In this subbase crossing structure 21a, a wall frame having a rectangular cross section composed of a ceiling portion 23, a bottom portion 24, and a side wall portion 25 is constructed by combining the PC roof girder 17 of the present invention and the PC roof girder 3 of the conventional structure. Similar to the first embodiment, an intermediate wall (intermediate column) 14 is provided between the ceiling portion 23 and the bottom portion 24 between the side wall portions 25.

  In the second embodiment, a wall is constructed by combining the PC roof girder 17 of the present invention and the conventional PC roof girder 3, and at least of the PC roof girders 17 and 3 constituting the ceiling portion 23 and the floor portion 24. A PC roof girder 17 having a plurality of hollow portions 16 according to the present invention is disposed at the upper and lower positions of the intermediate wall (intermediate support column) 14, and as in the first embodiment. The built-in girder 20 for structure in the PC roof girder 17 is provided in the upper and lower end faces of the intermediate wall 14. The plurality of hollow portions 16 of the PC roof girder 17 of the floor portion 24 that supports the lower end of the intermediate wall (intermediate column) 14 are filled with a time-curable filler 26 as shown in FIG. It is also possible to have a structure that can secure further strength. Other structures are the same as those of the first embodiment.

  According to the second embodiment, the same effects as those of the first embodiment can be obtained. That is, conventionally, since the intermediate wall 14 is disposed at the joint portion 15 avoiding the hollow portion 16 of the PC roof girder 3 in the ceiling portion 2 and the floor portion 4, it is difficult to assign the PC roof girder 3 in the left-right direction. However, in the second embodiment, instead of the joint portion 15 of the PC roof girder 17, the structural built-in girder 20 formed between the hollow portions 16 is positioned in the end surface of the intermediate wall 14. The strength can be secured and the intermediate wall 14 can be joined. Since the built-in girder 20 is a part of the PC roof girder 17 which is a single member, the PC roof girder 17 can be easily and reliably positioned by positioning the PC roof girder 17 and press-fitting it in combination with the conventional PC roof girder 3. The built-in girder 20 can be positioned within the end surface of the intermediate wall 14, and the allocation of the PC roof girders 17 on the ceiling portion 23 and the floor portion 24 is facilitated.

  In the first and second embodiments, the PC roof girder 17 can be efficiently press-fitted by a conventional square steel pipe preceding and following propulsion replacement method. Referring to FIGS. 5 to 6, the square steel pipe 27 has a cutting edge 27 a at the tip, and a tapered slope 27 b is provided inside the tip. A screw auger 29 is inserted through the hollow portion 28 of the square steel pipe 27, and these are connected to a propulsion device 31 equipped on the start shaft 30, and the ground at the tip of the square steel tube 27 is excavated by the screw auger 29, and the excavated soil is hollowed out. 28, the required number of rectangular steel pipes 27 are advanced in advance by the operation of the propulsion unit 31 and are engaged with the fittings 32 of the adjacent rectangular steel pipes 27 along the contour of the structure to be built. And the square steel pipe 27 more than the number of the same width as the PC roof girder 17 which concerns on this invention is propelled sequentially from the starting shaft 30 to the reaching shaft.

  Thereafter, the front end portion of one PC roof girder 17 is fitted and joined to the rear end portion of the plurality of square steel pipes 27, and the rear end portion of the PC roof girder 17 is moved by the propulsion device 31 on the start shaft 30 side. The PC roof girder 17 and the PC roof girder 17 are replaced by press-fitting the PC roof girder 17 over the entire length of the arrival side shaft while pushing and pushing the square steel tube 27 out of the arrival side shaft 33. .

  When the PC roof girder 17 is press-fitted, the rectangular steel pipe 27 is pressed in a stable state while engaging the fitting metal member 12 also serving as a guide fitting, and the pushed-out square steel pipe 27 is pushed out with a relatively small propulsive force. After 27, it can be surely press-fitted. Moreover, in the present invention, the PC roof girder 17 corresponds to a plurality of conventional PC roof girders, so that the conventional plurality of PC roof girders can be replaced at a time, and the replacement construction cycle is reduced to 1 /. It can be shortened from 2 to a fraction (that is, depending on the number of hollow portions).

  Further, the press fitting method of the PC roof girder is to press the PC roof girder following the square steel pipe 27 after the square steel pipe 27 is press-fitted in advance from the starting part to the reaching part while discharging excavated soil through the hollow part. Thus, it is possible to use a conventionally known press-fitting method of a PC roof girder in which the PC roof girder is pressed into the ground while pushing out the square steel pipe 27 from the reaching part. In this case, a plurality of square steel pipes 27 are excavated through the respective hollow parts. After discharging the earth and sand and sequentially press-fitting from the starting part to the reaching part and arranging them in parallel, the PC roof girder 17 of the present invention is made to follow the plurality of rectangular steel pipes 27, and the PC roof girder 17 is pressed. Thus, the PC roof girder 17 may be press-fitted into the ground while simultaneously pushing out a plurality of rectangular steel pipes 27 from the reaching portion.

As described above, the PC roof girder 17 is press-fitted while replacing the square steel pipe 27, but one PC roof girder 17 of the present invention corresponding to two conventional PC roof girders can be press-fitted. Therefore, the use of the PC roof girder 17 makes it possible to shorten the replacement construction cycle by half compared to the conventional case. Further, the positional relationship between the hollow portions 28 in the plurality of parallel square steel pipes 27 in FIG. 5A and the hollow portions 16 in the PC roof girder 17, or both end portions of the intermediate wall 14 in FIGS. As can be seen from the positional relationship of the hollow portions 16 of the PC roof girders 17 and 3 installed in the PC roof girder 17, the interval between the hollow portions 16 in the width direction of the single PC roof girder 17 of the present invention is one conventional hollow. The PC roof girder 17 having the plurality of hollow portions 16 has the same interval as the PC roof girder 3 having the portion 16 propelled in parallel. Further, as described in paragraph 0021, the PC roof girder 17 of the present invention may be provided with three or more hollow portions 16 to include a plurality of internal girder.

  Furthermore, the PC roof girder 17 of the present invention does not require one or more sets of joint hardware 12 disposed on both sides of the girder, and further, a joint part for processing the joint portion 15 of the adjacent PC roof girder 17 is provided. It can be almost halved and the construction process can be simplified. Furthermore, the formwork at the time of manufacturing the PC roof girder 17 only needs to widen only the bottom plate, and the side frame can be diverted as before, which is also economical in this respect. In addition, this invention is applicable also to a subbase crossing structure without an intermediate wall (support | pillar).

(A) is a perspective view of a PC roof girder according to the present invention, and (b) is a perspective view of a conventional PC roof girder. It is front explanatory drawing of the subbase crossing structure which concerns on Embodiment 1 of this invention. It is sectional drawing which expands and shows a part of FIG. It is front explanatory drawing of the subbase crossing structure which concerns on Embodiment 2 of this invention. (A) is a perspective view showing an embodiment in which the PC roof girder of the present invention is constructed by replacing the square steel pipe with a propulsion method, and (b) is a cross-sectional explanatory view showing the PC roof girder that is press-fitted into the ground. is there. (A) is a longitudinal cross-sectional explanatory view in a state where a square steel pipe is press-fitted in the replacement propulsion method, and (b) is a vertical cross-sectional explanatory view in a state where the rear end of the square steel pipe is pressed and pushed by a PC roof girder. It is. It is front explanatory drawing of the conventional subbase crossing structure. It is sectional drawing which expands and shows a part of FIG.

DESCRIPTION OF SYMBOLS 1 Subbase crossing structure 2 Ceiling part 3 PC roof girder 4 Floor part 5 Corner steel box girder 6 Side plate 7 Fixing metal fitting 8 Side fastening PC steel bar 9 Side wall part 10 Side fastening PC steel bar 11 Time-hardening material 12 Joint Hardware 13 Joint material 14 Intermediate wall (intermediate strut)
DESCRIPTION OF SYMBOLS 15 Seam part 16 Hollow part 17 PC roof girder 17a PC roof girder main body 18 Cast-in-place concrete block 19 for allocation adjustment Sheath 20 Built-in girder 21 Subbase crossing structure 21a Subbase crossing structure 23 Ceiling part 24 Floor part 25 Side wall part 26 Filler 27 Square steel pipe 27a Blade 27b Slope 28 Hollow part
29 Screw auger 30 Starting shaft 31 Propulsion machine 32 Joint hardware

Claims (2)

A prestressed concrete roof girder (hereinafter referred to as a PC roof girder) that is press-fitted so as to cross the roadbed base plate, and has a pair of joint hardware on both sides of the PC roof girder body, and a member of the PC roof girder body In a PC roof girder having a hollow portion that is continuous in the longitudinal direction, a plurality of hollow portions that communicate with each other in the longitudinal direction of the member are provided in parallel with a gap in the width direction. The same interval as the PC roof girder having the one hollow part which is adjacent to the PC roof girder having the joint metal fitting also used as a guide and having the joint metal fitting also used as a guide The parallel roof composite girder is characterized in that it is a PC roof girder having a plurality of such hollow portions, and the partition wall between adjacent hollow portions is a built-in girder for structure. PC roof girder having a hollow portion.   In a subbase crossing structure having a plurality of ceiling PC roof girders that are press-fitted so as to cross the roadbed foundation and a plurality of flooring PC roof girders, provided at least between the ceiling and the floor. The vertical end of the intermediate wall has a built-in girder for construction in a PC roof girder having a plurality of parallel hollow portions according to claim 1 provided on a ceiling portion and a floor portion provided on the floor portion. A sub-base crossing structure characterized in that it is provided so as to be interposed between a built-in girder for construction in a PC roof girder having a plurality of hollow portions arranged in parallel.

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