JP2018053496A - Bridge girder erection method for multiple span continuous bridge - Google Patents

Abstract

A bridge girder erection method for a multi-span continuous bridge is provided, in which bridge girders composed of PCa segments can be constructed using erection girders shorter than conventional ones. A rear end of an erection girder 30 is supported by a rear overhang girder 11 in an erection span S0 via a support part 33, and an intermediate part of the erection girder 30 is supported by a front column head 4F in the erection span S0. The erection girder 30 is arranged so that it is formed (Fig. 6(A)). After that, the PCa segment 5 is arranged using the erection girder 30, the front overhang girder 12, the rear overhang girder 111 of the next span S1, and the girder connection part 16 are constructed, and the rear pier 2B and the front pier 2F are constructed. bridge girder 3 is laid over (Fig. 6 (B) to (C)). After that, the rear end of the erection girder 30 is supported by the rear overhang girder 111 of the next span S1 via the support part 33, and the intermediate part of the erection girder 30 is supported by the front column head 4F1 of the next span S1. The installation girder 30 is moved as shown in FIG. 7 and FIG. By repeating these steps, the bridge girders 3 are continuously constructed over a plurality of spans S. [Selection drawing] Fig. 6

Description

  The present invention relates to a multi-span continuous bridge girder erection method in which a bridge girder composed of a plurality of precast segments is erected between the diameters of a plurality of piers arranged with a predetermined span.

  As a concrete bridge or a composite bridge of concrete and steel, there is a precast segment bridge in which a bridge girder is divided into a plurality of blocks in the bridge axis direction, and each block is constructed by a precast (PCa) segment. There are span-by-span construction methods, cantilever construction methods (balanced cantilever construction method), etc. for precast segment bridge construction methods.

  As a span-by-span construction method, for example, an installation girder (erection girder) is arranged so as to straddle the span between which the bridge girder is to be installed (hereinafter referred to as the installation span), and a plurality of hangers suspended from the installation girder A hanger type is known in which these PCa segments are joined in a state where each PCa segment is hung, and a bridge girder is constructed by spanning one span by placing concrete for placement, and laying and tensioning external cables. Yes (for example, see Patent Documents 1 and 2).

  As a cantilever erection method, a erection method using a movable erection vehicle (erection nose) or a erection method using a erection girder is known. When the erection girder is used, the provisional equipment cost increases due to the increase in the size of the erection facility, and the construction period can be shortened because the number of times the erection facility is moved is reduced as compared with the case where the erection work vehicle is used. Therefore, the erection girder is suitable for construction of a multi-span continuous bridge where erection work is repeatedly performed.

JP-A-8-134845 JP 2001-131918 A

  However, in the construction method in which the PCa segment is erected using the erection girder, the erection work is carried out with the erection girder placed on the pier (column head) and the erection girder is moved to the next diameter. For this purpose, the installation girder is required to have a length of at least two spans. Therefore, the weight of the installation girder increases and the construction cost increases. If the span is long, a tower is installed at the center of the installation girder, and the installation girder can be reduced in weight by supporting the span of the installation girder with an oblique cable extending diagonally from the tower. In such a configuration, it is necessary to adjust the oblique cable, so that maintenance is complicated. Further, when the weight of the erection girder increases, the supporting load required for the pier increases, and the construction cost of the entire bridge increases due to the increase in the size of the substructure.

  This invention makes it a subject to provide the bridge girder construction method of the multi-span continuous bridge which can construct | assemble the bridge girder which consists of a PCa segment using a shorter girder than before in view of such a background.

In order to solve such a problem, the present invention provides a bridge girder (3) comprising a plurality of PCa segments (5) between each diameter of a plurality of piers (2) arranged with a predetermined span (S). A bridge girder erection method for a multi-span continuous bridge (1) to be erected, comprising a plurality of support portions (33), which is longer than the span and shorter than twice the span. Through the first step (FIGS. 2 (A) and 6 (A)) and the support portion (33), the rear end of the installation girder (30) is behind the installation span (S ₀ ). It is supported by a rear overhanging girder (11) projecting forward from a rear column head (4B) provided on the pier (2B), and an intermediate portion of the installation girder (30) is located between the installation spans (S ₀ ). The installation girder (30) is arranged at the start position supported by the front column head (4F) provided on the front pier (2F). The PCa segment (5) is arranged using the second step (FIGS. 2 (A) and 6 (A)) and the installation girder (30), and rearward from the front column head (4F). front projecting toward ChoIzuruketa (12), a rear ChoIzuruketa ₍₁₁ 1) of the next span _{(S 1)} projecting forward from the front stigmas unit (4F), and the erection span ( S ₀₎ said rear ChoIzuruketa (11) and said front ChoIzuruketa (12) connecting the girder connecting portion constructed (16) in said rear abutment (2B in the erection span _{(S 0)} ) And the third step (FIG. 2 (B) to FIG. 2 (C), FIG. 3 (F) to FIG. 4 (G), FIG. 6 (B)) that bridges the bridge girder (3) to the front pier (2F). 7 (D)) and the support portion (33), the rear end of the installation girder (30) is stretched forward from the front column head (4F). Is supported by the rear ChoIzuruketa (11 ₁₎ of the next span _{(S 1)} to issue, to the front pier of the intermediate portion is the next span _{(S 1)} (2F ₁₎ of the erection digits (30) A fourth step (FIGS. 3D to 3E and 4H) of moving the erection girder (30) forward to a completion position supported by the front column head (4F ₁ ) provided. By repeating FIG. 5 (J) and FIG. 7 (E) to FIG. 8 (I)), the bridge girder (3) is constructed continuously over a plurality of spans (S).

  According to this configuration, even if the erection girder is shorter than twice the span, the erection girder is installed so that the middle part of the erection girder is supported by the front column head between the next diameters for erection between the next diametries. Can be moved. Thereby, the bridge girder which consists of PCa segments can be sequentially constructed between the continuous diameters using the construction girder shorter than before.

Further, in the above invention, before the fourth step, a reinforcing first temporary PC cable (21 ₁ ) is provided in the rear overhanging girder (11 ₁ ) between the next spans (S ₁ ) and Steps for introducing stress (FIG. 2 (B), FIG. 6 (B)), and the bridge girder (S ₋₁ ) between the adjacent spans (S ₋₁ ) adjacent to the rear side where the bridge girder (3) is bridged in advance. 3 _-1) of bridged pass during the erection span (S ₀₎ of said rear ChoIzuruketa (11) to the first temporary PC cable for reinforcing which has been provided to introduce a prestress (21), A step of removing after the third step (FIGS. 4G and 6C) may be further provided.

  According to this configuration, before the rear end of the installation beam is supported by the rear extension beam between the next diameters in the cantilever support state, the rear extension beam between the next diameters is reinforced by the first temporary PC cable. . Therefore, in order to support the rear end of the installation girder in the second step repeated to install the bridge girder between the next diameters, it is necessary to enlarge the member cross section of the rear extension girder or the rear extension cable by using the completed PC cable There is no need to introduce pre-stress locally in the girder. In addition, since the first temporary PC cable is removed after the bridge girder is bridged between the rear pier and the front pier, the first temporary PC cable can be diverted to reinforce the rear extension girder between the spans to be installed later. The rise can be suppressed.

Further, in the above invention, in the third step, a plurality of the PCa segments (5) are formed in the rear overhanging girder (11) and the front overhanging girder (12) in the span span (S ₀ ). It is good to set it as the structure which connects sequentially by an overhanging construction system and constructs the said girder connection part (16) (FIG.2 (B)-FIG.2 (C), FIG.3 (F)).

  According to this configuration, the girder connecting portion can be constructed in the same manner as the front overhanging girder and the rear overhanging girder between the next diameters, and the work can be simplified by simplifying the construction equipment and unifying the work contents.

In the above invention, the third step is a step of constructing a rear extension girder (13) projecting further forward from the rear projecting girder (11) in the span span (S ₀ ) (FIG. 2 (B) to FIG. 2 (C)) and a front extension girder (14) that projects further rearward from the front extension girder (12) and is connected to the rear extension girder (13). 3 (F) to FIG. 4 (G), and the fourth step includes constructing the rear extension girder (13) and then via the support part (33), the erection girder. An intermediate portion of (30) is supported by the front overhanging girder (12) and the rear overhanging girder (11 ₁ ) between the next spans (S ₁ ), and a rear end of the installation girder (30) is Step of moving the erection beam (30) forward to an intermediate position supported by the rear extension beam (13) (FIG. (D) to (E)), and after constructing the front extension girder (14), moving the erection girder forward from the intermediate position to the completion position (FIGS. 4H to 5). J)).

  According to this configuration, the support part that supports the rear end of the installation girder is moved rearward by moving the installation girder forward so that the middle part of the installation girder is supported by the front extension girder and the rear extension girder. While extending away from the column head, the supporting load at the rear end of the installation beam is reduced, so that the front extension beam can be constructed with the bending moment of the rear extension beam reduced.

  Further, in the above invention, the third step includes the step of moving the erection beam (30) to the intermediate position where the rear end of the erection beam (30) is supported by the rear extension beam (13). After providing the second temporary PC cable (22) for reinforcement to the rear extension girder (13) and introducing prestress (FIG. 3 (D)), and constructing the front extension girder (14), It is preferable to further include a step (FIG. 4G) of removing the second temporary PC cable (22) provided on the rear extension girder (13).

  According to this configuration, the rear extension girder is reinforced by the second temporary PC cable before the rear end of the installation girder is supported by the rear extension girder in a cantilevered state. Therefore, it is necessary to enlarge the cross section of the rear extension girder and the rear extension girder or to complete the main PC so that the rear extension girder supports the rear end of the installation girder that constructs the front extension girder at the intermediate position. There is no need to introduce prestress locally to the rear extension girder or rear extension girder by the cable. In addition, since the second temporary PC cable is removed after the bridge girder is bridged between the rear pier and the front pier, the second temporary PC cable can be diverted to reinforce the rear extension girder between the next spans to be installed later, Increase in construction costs can be suppressed.

  Further, in the above invention, in the third step, the plurality of PCa segments (5) are connected in a hung manner in a suspended state to the erection beam (30) to construct the beam connection part (16). (FIG. 6C) A configuration can be adopted.

  According to this configuration, since a plurality of PCa segments in the girder connecting portion are joined together and the number of joining operations can be reduced, the construction period can be shortened.

  Thus, according to the present invention, it is possible to provide a bridge girder erection method for a multi-span continuous bridge capable of constructing a bridge girder composed of PCa segments using a girder shorter than conventional ones.

The side view which shows the bridge girder construction state of the multi span continuous bridge which concerns on 1st Embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 1st embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 1st embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 1st embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 1st embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 2nd embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 2nd embodiment Explanatory drawing of the bridge girder construction method of the multi span continuous bridge concerning a 2nd embodiment

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<< First Embodiment >>
First, with reference to FIGS. 1-5, the bridge girder construction method of the multi span continuous bridge 1 which concerns on 1st Embodiment is demonstrated. FIG. 1 is a side view showing a state in which a bridge girder of a multi-span continuous bridge 1 is being constructed. As shown in FIG. 1, the multi-span continuous bridge 1 includes a plurality of bridge piers 2 (2B, 2F) arranged in a row in a bridge axis direction with a predetermined span S (S _{−1 to} S ₁ ). And a plurality of bridge girders 3 that are spanned so as to be continuous between a pair of bridge piers 2 (diameter S) adjacent to each other in the bridge axis direction. The plurality of piers 2 are constructed prior to the construction of the bridge girder 3. Further, on each bridge pier 2, a column head 4 (4 </ b> B, 4 </ b> F) is constructed prior to the bridge girder 3 being bridged. The column head 4 may be constructed by including a segment made of PCa concrete, or may be constructed by cast-in-place concrete. The plurality of spans S may be constant or may vary. Here, a plurality of spans S will be described as having the same span length L1.

  Among the three piers 2 shown in FIG. 1, the bridge girder 3 has already been bridged between the pair of piers 2 on the left side of the leftmost pier 2, and FIG. The state which is performing the work which bridges the bridge girder 3 between the bridge piers 2 is shown. The bridge girder 3 is a box girder constructed by connecting a plurality of PCa segments 5 with a plurality of PC cables (not shown) of an external cable system extending in the bridge axis direction. The cross-sectional shape of the bridge girder 3 is not particularly limited, and may be a single box girder, a multi-main girder box girder, a multiple box girder, or the like. The bridge girder 3 is sequentially moved toward the right in FIG. Accordingly, the right side in FIG. 1 is the front and the left side is the rear.

Hereinafter, the span S on which the bridge girder 3 is being bridged is referred to as a span span S _0, and the span S adjacent to the rear side of the span span S ₀ on which the bridge span 3 has been bridged is referred to as a span S. referred to the previous span S _-1, adjacent to the front side of the erection span S _0, the span S of the bridge beam 3 has not yet been bridged referred to next span S _1. Also, of the pier 2 a pair before and after configuring the erection span S _0, referred to pier 2 located on the rear side and the rear abutment 2B, referred piers 2 positioned on the front side with the front pier 2F. Furthermore, the column head 4 constructed on the rear pier 2B is referred to as a rear column head 4B, and the column head 4 constructed on the front pier 2F is referred to as a front column head 4F.

For example, bridge piers 2 called front abutment 2F is to hung pass is complete bridge girder 3 erection span S _0, when performing pass work hung bridge girder 3 follows span S ₁ is referred to as rear abutment 2B Will be. Therefore, both the names of these piers 2 and column heads 4 are based on the span span S ₀ , and when used for the tip span S ₋₁ and the next span S ₁ , the span span S is used. are denoted by the corresponding subscript, referred to as front column capital portion 4F ₁ like the following span S _1. The same applies to members such as the bridge girder 3 and a rear overhanging girder 11 described later. When referring or when collectively used for the erection span S ₀ is omitted subscripts corresponding to the span S.

In the state of FIG. 1, the erection span S _0, a rear ChoIzuruketa 11 projecting with about one length of 4 minutes of span length L1 toward the rear stigmas portion 4B on the front, from the front stigmas portion 4F A front overhanging girder 12 is extended (constructed) in a cantilevered state so as to project rearward with a length of about one quarter of the span length L1. Further, the rear ChoIzuruketa 11 ₁ of the following span S ₁ projecting with about one length of 4 minutes of span length L1 toward the front from the front stigmas portion 4F is bridged by a support cantilever state. The rear overhanging girder 11 of the span span S ₀ is composed of a plurality of PCa segments 5 sequentially joined to the front surface of the rear column head 4B, and the front overgirder 12 is sequentially joined to the rear surface of the front column head 4F. The plurality of PCa segments 5 are formed. Rear ChoIzuruketa 11 ₁ of the following span S ₁ is composed of a plurality of PCa segments 5 which are sequentially joined to the front surface of the front column capital portion 4F.

Rear ChoIzuruketa 11 and front ChoIzuruketa 12 erection span _{S 0,} and each PCa segment 5 constituting the rear ChoIzuruketa 11 ₁ of the following span _{S 1,} the rear stigmas portion 4B or forward stigmas portion 4F The column head 4 or the PCa segment 5 arranged adjacent to the column head 4 side by the tension of a plurality of PC cables provided to be fixed at both ends to a pair of PCa segments 5 arranged symmetrically with respect to the center. Are joined to each other.

Moreover, erection span _S rear ChoIzuruketa 11 and front ChoIzuruketa _{12 -1} at the top of the previous span _{S -1 0,} and rear ChoIzuruketa 11 ₁ and erection span S of the next span _{S 1} on top of the front ChoIzuruketa 12 _0, the first temporary PC cable 21, 21 ₁ for reinforcing the outer cable system is provided. The first temporary PC cable 21 ₁ is fixed to the front end in PCa segments 5 arranged on the most overhanging side at the rear ChoIzuruketa 11,11 _1, front ChoIzuruketa ₁₂ -1, most Zhang in 12 The rear end is fixed to the PCa segment 5 arranged on the outlet side. Rear ChoIzuruketa 11, 11 ₁ and the front ChoIzuruketa ₁₂ -1, the bending strength of 12 is reinforced by the tensioning force applied to the first temporary PC cable 21 _1.

In other embodiments (e.g., a second embodiment will be described with reference to FIGS. 6 to 8), the first temporary PC cable 21 _1, the corresponding front ChoIzuruketa ₁₂ -1, after 12 instead of the end is fixed, the corresponding rear column capital portion 4B becomes the rear ChoIzuruketa 11, 11 ₁ of the overhang bases, it may be provided to the rear end to 4B ₁ is fixed.

On the span between spans S ₀ , a construction girder 30 is disposed for placing the PCa segment 5 conveyed on a bridge girder 3 already constructed by a transportation vehicle 6 such as a trailer at a predetermined construction position. The main body portion of the erection girder 30 is composed of two truss girders 31 that are connected in a state of being spaced apart from each other and extend in the bridge axis direction. A lifting device 32 such as a portal crane is provided on the upper portion (upper chord material) of the erection girder 30 so as to straddle the two truss girders 31 so as to be movable in the bridge axis direction. On the other hand, a plurality of (three in the illustrated example) support portions 33 (33R, 33M, and 33F) that support the installation girder 30 are provided below the installation girder 30 (lower chord material). At least three support portions 33 are provided, and all the support portions 33 are movable in the bridge axis direction.

  In another embodiment, the rear support portion 33R arranged at the rearmost position is fixed to the installation girder 30, and a plurality of (two in the illustrated example) support portions 33 may be movable in the bridge axis direction. Good. In this case, the rear support portion 33 </ b> R can be moved (running or self-propelled) with respect to the bridge girder 3, and moves on the bridge girder 3 together with the main body portion of the installation girder 30.

In the state of FIG. 1, the installation girder 30 is extended to the rear span girder 11 that has been installed over the installation span S ₀ via the rear support part 33R and the middle support part 33M disposed in the middle in the front-rear direction. The intermediate portion is supported by the front column head portion 4F via the front support portion 33F disposed at the foremost position. The installation girder 30 has a length in the bridge axis direction that is longer than the span length L1 and shorter than twice the span length L1, and the front end is the next diameter in a state where the rear end overlaps the rear overhanging girder 11. The rear projecting girder 11 _{1 of the} space S ₁ projects forward. Hereinafter, this position of the erection girder 30 is referred to as a start position.

Incidentally, fried rail provided for movement of the heavy device 32, as shown, need not be provided over the entire length of the installation digit 30, a rear Zhang follows span S ₁ in the arrangement state shown in FIG. 1 Deketa 11 ₁ may have a length capable of bridging overhanging the. Front end portion 30a of the erection digits 30 which rail is not provided serves as a hand caster for moving the erection digits 30 to erection for the location of the next span S _1. The front end of the installation digits 30, during the movement of the erection digit 30, front end support legs 34 for supporting the front end of the erection digits 30 until placing front support portion 33F on the front pier 2F ₁ follows span S ₁ Is provided. In addition, the erection girder 30 is provided with an intermediate support leg 35, a suspension scaffold (not shown), and the like.

  Next, with reference to FIGS. 2 to 5, a procedure for installing the bridge girder 3 in one span S will be described.

FIG. 2 (A) shows a state of the erection cycle bridge girder 3 in erection span S _0. As shown in the figure, at the span span S ₀ , the rear overhanging girder 11 projecting forward from the rear column head 4B is already installed, and the installation girder 30 is in the same state as in FIG. The rear end is supported by the rear overhanging girder 11 via the rear support portion 33R and the middle support portion 33M, and the intermediate portion is disposed at the start position supported by the front column head 4F via the front support portion 33F.

Using the installation girder 30 arranged in this way, as shown in FIG. 2 (B), the front extension girder 12 of the installation span S ₀ extending rearward from the front column head 4F, from front stigmas portion 4F and the rear ChoIzuruketa 11 ₁ of the following span S ₁ projecting forward to erection by cantilever construction method. Specifically, one PCa segment 5 is disposed behind and in front of the front column head 4F, and a pair of PCa segments 5 sandwiching the front column head 4F are connected by a PC cable to be cantilevered. The work of erection in the state is repeated for a predetermined number of times. Front ChoIzuruketa 12 and after erection and rear ChoIzuruketa 11 ₁ of the following span _{S 1,} front ChoIzuruketa 12 erection span _{S 0} from the rear ChoIzuruketa 11 ₁ of the following span _{S 1} the first temporary PC cable 21 ₁ over provided to introduce a prestress.

  Thereafter, as shown in FIG. 2 (C), the rear extension girder 13 projecting forward from the rear extension girder 11 is erected by a cantilever construction method. Specifically, the PCa segment 5 constituting the rear extension beam 13 is disposed at a predetermined position, and tension is applied to a PC cable (not shown) that is stretched so that the rear end is fixed to the rear column head 4B. By fixing the front end of the cable to the PCa segment 5, the operation of joining the PCa segment 5 to the PCa segment 5 disposed adjacent to the rear is repeated.

Next, as shown in FIG. 3 (D), a pre-stress is introduced by providing a reinforcing second temporary PC cable 22 to the rear extension beam 13. Specifically, the second temporary PC cable 22 is stretched forward from the rear column head 4B so that the rear end is fixed to the rear column head 4B, and the rear extension girder is stretched while the second temporary PC cable 22 is in tension. The front end is fixed to the PCa segment 5 arranged on the most protruding side of 13. Thereafter, the medium supporting portion 33M on the front ChoIzuruketa 12, the rear support portion 33R on the front end of the rear extension digit 13, a front support portion 33F on the rear ChoIzuruketa 11 ₁ of the following span _{S 1} Move sequentially.

After the arrangement of the support portion 33 is completed, as shown in FIG. 3E, the erection beam 30 (two truss beams 31 and the lifting device 32) is moved forward, and the rear end of the erection beam 30 is It is supported on the front end of the rear extension digits 13 via the rear support portion 33R, erection girder 30 intermediate portion rear part of the front ChoIzuruketa 12 and next span S ₁ via the middle support unit 33M and the front support portion 33F of placing the erection digits 30 to an intermediate position where it is supported by the ChoIzuruketa 11 _1.

  Subsequently, as shown in FIG. 3 (F), the front extension girder 14 projecting rearward from the front projecting girder 12 is constructed by a cantilever construction method. Specifically, the PCa segment 5 constituting the front extension beam 14 is disposed at a predetermined position, and tension is applied to a PC cable (not shown) that is stretched so that the front end is fixed to the front column head 4F. By fixing the rear end of the cable to the PCa segment 5, the operation of joining the PCa segment 5 to the PCa segment 5 arranged adjacent to the front is repeated. Between the rear extension girder 13 and the front extension girder 14, there is provided a closing portion 15 that connects the overhanging girder from the rear column head 4B and the overhang girder from the front column head 4F. The closing part 15 may be constructed by a cast-in-place concrete, or may be constructed by providing a closing part segment and placing place joints at both ends thereof.

  After the concrete of the closing portion 15 is hardened, as shown in FIG. 4G, a complete PC cable 23 is provided so as to extend from the rear column head 4B to the front column head 4F. The completed PC cable 23 is provided at the upper part of the bridge girder 3 in the rear column head 4B and the front column head 4F, and is provided at the lower part of the bridge girder 3 in the center of the span such as the closing part 15. Then, tension is applied to the completed PC cable 23, the rear end of the completed PC cable 23 is fixed to the rear column head 4B, and the front end is fixed to the front column head 4F, so that prestress is introduced to the bridge girder 3. Thereby, the girder connection part 16 which connects the rear overhanging girder 11 and the front overhanging girder 12 is constructed.

Thereafter, the first temporary PC cable 21 and the second temporary PC cable 22 (see FIG. 3F) are removed. The first temporary PC cable 21 after removal, the second temporary PC cable 22 is diverted to the reinforcing of the rear ChoIzuruketa 11 ₂ which are bridged overhangs next span _{S 2} of the next span _{S 1,} the removed following diverting to reinforce the rear extension digits 13 ₁ of span _{S 1.}

Subsequently, as shown in FIG. 4 (H), erection as a movement preparation digit 30, a middle supporting portion 33M in the vicinity of the front end of the rear ChoIzuruketa 11 ₁ of the following span _{S 1,} before the rear support portion 33R near the rear end of BuCho Deketa 12, before sequentially moved forwardly to the support portion 33F from the rear ChoIzuruketa 11 ₁ which is laid protrudes rearward pier 2B ₁ follows span S _1.

After the arrangement of the support portion 33 is completed, as shown in FIG. 4 (I), the erection beam 30 (two truss beams 31 and the lifting device 32) is moved forward, and the front end of the erection beam 30 is moved to through the front supporting leg 34 is supported on the front column capital portion 4F ₁ follows span S _1.

Thereafter, as shown in FIG. 5 (J), before the supporting portion 33F is supported the front end of the erection digit 30 placed over the front column capital portion 4F ₁ follows span S ₁ before the support portion 33F, a rear support after the part 33R is arranged in the vicinity of the front end of the rear ChoIzuruketa 11 ₁ of the following span S _1, further moving the erection digit 30 forward. Then, the next diameter erection digit 30, rear end through the rear supporting portion 33R and the middle support portion 33M is supported to the rear ChoIzuruketa 11 ₁ of the following span S _1, the intermediate portion through the front supporting portion 33F placing a completion position which is supported to the front column capital portion 4F ₁ between S _1. Thereby, it will be in the same state as FIG. 2 (A), and the construction cycle of the bridge girder 3 in one span S will be completed.

  By repeating the above procedure, the bridge girder 3 of the multi-span continuous bridge 1 is constructed over the plurality of bridge piers 2.

In the present invention employing such a procedure, as shown in FIG. 2 (A), the rear end of the installation beam 30 is supported by the rear overhanging beam 11, and the middle part of the installation beam 30 is attached to the front column head 4F. After the installation girder 30 is arranged to be supported, the installation girder 30 is used as a front as shown in FIGS. 2 (B) to 2 (C) and FIGS. 3 (F) to 4 (G). constructs a BuCho Deketa 12 and column connecting portion 16 in addition to bridging the bridge beam 3, to construct a rear ChoIzuruketa 11 ₁ of the following span _{S 1,} FIG. 3 (D) ~ FIG 3 (E) moves the erection digit 30, as shown in FIG. 4 (H) ~ FIG 5 (J) to erection position of the next span _{S 1.} Therefore, even erection digit 30 is shorter than twice the span S (span length L1), the front stigma portion of the intermediate portion of the erection digit 30 next span S ₁ for the erection of the next span S ₁ The installation girder 30 can be moved so as to be supported by 4F ₁ . Thereby, the bridge girder 3 which consists of the PCa segment 5 can be sequentially constructed in the continuous span S using the construction girder 30 shorter than before.

Further, in this embodiment, before moving the erection digit 30 to the next span _{S 1} in FIG. 3 (D) ~ FIG 3 (E), as shown in FIG. 2 (C), the next span _{S 1} rear ChoIzuruketa 11 ₁ provided with first temporary PC cable 21 for reinforcement is prestressed in. Thus, prior to supporting the rear ChoIzuruketa 11 ₁ rear a cantilevered state of erection digits 30 to bridging the bridge beam 3 of _the following span S ₁ as shown in FIG. 5 (J) further, prior to supporting the rear ChoIzuruketa 11 ₁ of the intermediate portion cantilevered state of erection digits 30 to build a girder connecting portion 16 of the erection span S as shown in FIG. 3 (D) , rear ChoIzuruketa 11 ₁ is reinforced by the first temporary PC cable 21. Therefore, bridging the rear end or intermediate portion of the spar 30 to be supported, the following span S ₁ of the rear ChoIzuruketa 11 _first member section next span S by complete PC cable 23 of necessary or present set the size of the there is no need to introduce locally prestress ₁ rear ChoIzuruketa 11 _1. Further, as shown in FIG. 2 (A), it was provided to introduce a pre prestress the rear ChoIzuruketa 11 erection span S ₀ when hung bridge girder 3 _-1 in the previous span S _-1 The first temporary PC cable 21 for reinforcement is removed after the bridge girder 3 is bridged in FIG. Therefore, the removed first temporary PC cable 21 can be diverted for reinforcement of the rear overhanging girder 11 of the span S to be installed later. As a result, an increase in the construction cost can be suppressed.

In this embodiment, when the bridge girder 3 is bridged over the span span S ₀ using the erection girder 30, as shown in FIGS. 2 (B) to 2 (C) and FIG. 3 (F), A plurality of PCa segments 5 are sequentially connected to the rear overhanging girder 11 and the front overhanging girder 12 in the span S ₀ by the overhanging construction method, thereby constructing the girder connecting portion 16. Therefore, in the same manner as the rear ChoIzuruketa 11 ₁ of the front ChoIzuruketa 12 and next span S ₁ can build digits connecting portion 16, thereby simplifying the work by unification of simplification and work erection equipment.

Further, as shown in FIG. 2 (C), a rear extension girder 13 projecting further forward from the rear overhanging girder 11 is constructed and supported as shown in FIGS. 3 (D) and 3 (E). through the section 33, an intermediate portion of the erection digit 30 is supported on the front ChoIzuruketa 12 and rear ChoIzuruketa 11 ₁ of the following span S _1, the rear end of the erection digit 30 is supported on the rear extension digits 13 As shown in FIG. 3 (F) and FIG. 4 (G), the erection girder 30 is moved forward so as to project further rearward from the front projecting girder 12 and connected to the rear extension girder 13. The front extension girder 14 is constructed. In other words, the mobile erection digit 30, as shown in FIG. 3 (E), an intermediate portion of the erection digit 30 is supported on the rear ChoIzuruketa 11 ₁ of the front ChoIzuruketa 12 and next span S ₁ is forward In this state, the rear support portion 33R that supports the rear end of the erection beam 30 is farther from the rear column head 4B than the state of FIG. . Thereby, the front extension girder 14 can be constructed in a state where the bending moment of the rear overhanging girder 11 is reduced as compared with the state of FIG.

Furthermore, before the installation girder 30 is moved to an intermediate position where the rear end of the installation girder 30 is supported by the rear extension girder 13 in FIG. 3 (E), as shown in FIG. A pre-stress is introduced by providing a second temporary PC cable 22 for reinforcement. Therefore, it is necessary to enlarge the member cross section of the rear extension girder 13 or the rear extension girder 11 so that the rear extension girder 13 supports the rear end of the installation girder 30 that constructs the front extension girder 14 at an intermediate position. It is not necessary to introduce prestress locally to the rear extension girder 13 or the rear overhanging girder 11 by the completed PC cable 23 of this installation. 3 (F) and FIG. 4 (G), after constructing the front extension girder 14, the second temporary PC cable 22 provided on the rear extension girder 13 as shown in FIG. 4 (G). Removed. Therefore, after the reinforcement of the rear extension digits 13 ₁ of the following span S ₁ to perform the erection work can be diverted to a second temporary PC cable 22. As a result, an increase in the construction cost can be suppressed.

<< Second Embodiment >>
Next, with reference to FIGS. 6-8, the construction procedure of the bridge girder 3 which concerns on 2nd Embodiment is demonstrated. The structure of the multi-span continuous bridge 1 and the erection girder 30 used for its construction are the same as in the first embodiment. In the present embodiment, the construction method of the girder connecting portion 16 is mainly different from the first embodiment. Below, the same code | symbol is attached | subjected to the element which is the same or the same as that of 1st Embodiment, or a function, and the overlapping description is abbreviate | omitted suitably.

FIG. 6 (A) shows a state of the erection cycle bridge girder 3 in erection span S _0. This state is the same as that shown in FIG. 2A, that is, the rear overhanging girder 11 has already been installed in the installation span S ₀ , and the installation girder 30 is moved to the rear part via the rear support part 33R and the middle support part 33M. The rear end is supported by the overhanging girder 11 and the intermediate part is supported by the front column head 4F via the front support part 33F. Also in the present embodiment, by using the installation girder 30 arranged in this way, as shown in FIG. 6 (B), the installation span S ₀ that projects rearward from the front column head 4F. a front ChoIzuruketa 12, is bridged by a bridging method has a rear ChoIzuruketa 11 ₁ of the following span S ₁ projecting forward from the front stigmas unit 4F piece. After erection the front ChoIzuruketa 12 and the rear ChoIzuruketa 11 ₁ of the following span _{S 1,} the rear ChoIzuruketa 11 ₁ of the following span _{S 1,} prestressing is provided a first temporary PC cable 21 Is introduced.

  On the other hand, in this embodiment, thereafter, as shown in FIG. 6C, the beam connecting portion 16 that connects the rear protruding beam 11 and the front protruding beam 12 is constructed by the hanger method. Specifically, the work is performed as follows.

  First, the plurality of PCa segments 5 constituting the rear extension beam 13 protruding forward from the rear extension beam 11 are arranged at predetermined positions while being suspended by the installation beam 30 via the suspension member 36. Further, a plurality of PCa segments 5 constituting the front extension beam 14 projecting rearward from the front projecting beam 12 are arranged at predetermined positions in a state where the PCa segments 5 are suspended by the installation beam 30 via the suspension member 36. To do. Then, tension is applied to a PC cable (not shown) stretched so that the rear end is fixed to the rear column head 4B, and the front end of the PC cable is connected to the front end of the plurality of PCa segments 5 constituting the rear extension beam 13. The plurality of PCa segments 5 are collectively joined to the rear overhanging girder 11 by fixing to the arranged one. Further, tension is applied to a PC cable (not shown) stretched so that the front end is fixed to the front column head 4F, and the rear end of the PC cable is connected to the rear of the plurality of PCa segments 5 constituting the front extension beam 14. The plurality of PCa segments 5 are joined together to the front overhanging girder 12 by fixing to the one arranged at the end. The closing part 15 provided between the rear extension girder 13 and the front extension girder 14 is constructed by using cast-in-place concrete, or by providing a closing part segment and placing place joints at both ends thereof. There is a case.

After the concrete of the closing portion 15 is hardened, a complete PC cable 23 is provided so as to extend from the rear column head 4B to the front column head 4F, tension is applied to the completed PC cable 23, and the rear end of the completed PC cable 23 is attached. Prestress is introduced into the bridge girder 3 by fixing to the rear column head 4B and fixing the front end to the front column head 4F. Thereby, the girder connection part 16 which connects the rear overhanging girder 11 and the front overhanging girder 12 is constructed. Then, remove the first temporary PC cable 21 which is provided in the rear ChoIzuruketa 11 erection span _{S 0.} The first temporary PC cable 21 removed is diverted to reinforce the rear ChoIzuruketa 11 ₂ to be laid in the next span _{S 2} of the next span _{S 1.}

Thereafter, as shown in FIG. 7D, the suspension member 36 that has suspended the PCa segment 5 is removed. Subsequently, as shown in FIG. 7E, in preparation for the movement of the erection beam 30, the middle support portion 33 </ b> M is placed on the front extension beam 12, and the rear support portion 33 </ b> R is placed on the front end of the rear extension beam 13. sequentially moving the front support portion 33F on the rear ChoIzuruketa 11 ₁ of the following span _{S 1.}

After the placement of the support portion 33 is completed, as shown in FIG. 7 (F), the erection beam 30 (two truss beams 31 and the lifting device 32) is moved forward, and the rear end of the erection beam 30 is It is supported on the front end of the rear extension digits 13 via the rear support portion 33R, erection girder 30 intermediate portion rear part of the front ChoIzuruketa 12 and next span S ₁ via the middle support unit 33M and the front support portion 33F of placing the erection digits 30 to be supported in ChoIzuruketa 11 _1.

Thereafter, as shown in FIG. 8, the erection girder 30 is further moved. The work shown in FIG. 8 is the same as the work described in FIG. That is, first, as shown in FIG. 8 (G), the middle support part 33M in the vicinity of the front end of the rear ChoIzuruketa 11 ₁ of the following span _{S 1,} after the rear support portion 33R of the front ChoIzuruketa 12 the end vicinity, sequentially moves further forward than the front support portion 33F rear ChoIzuruketa 11 ₁ of the following span S _1. Thereafter, as shown in FIG. 8 (H), to move the erection digit 30 forward, the front end of the erection digit 30, is supported on the front column capital portion 4F ₁ follows span S ₁ through the front support legs 34 . Subsequently, as shown in FIG. 8 (I), before the supporting portion 33F is supported the front end of the erection digit 30 placed on the front stigma portion 4F of the next span S ₁ before the support portion 33F, a rear support after the part 33R is arranged in the vicinity of the front end of the rear ChoIzuruketa 11 ₁ of the following span S _1, further moving the erection digit 30 forward. Thereby, it will be in the same state as FIG. 6 (A), and the construction cycle of the bridge girder 3 in one span S will be completed.

  By repeating the above procedure, the bridge girder 3 of the multi-span continuous bridge 1 is constructed over the plurality of bridge piers 2.

Also in the present embodiment, as shown in FIG. 6 (A), the rear end of the installation beam 30 is supported by the rear overhanging beam 11, and the middle part of the installation beam 30 is supported by the front column head 4F. After the installation girder 30 is arranged, as shown in FIGS. 6 (B) to 7 (D), the front extension girder 12 and the girder connecting part 16 are constructed using the installation girder 30 to construct the bridge girder 3. in addition to bridging, to construct a rear ChoIzuruketa 11 ₁ of the following span _{S 1,} erection position erection digit 30 of the next span _{S 1} as shown in FIG. 7 (E) ~ FIG 8 (I) The point of moving to is the same as in the first embodiment.

Also, before moving the erection digit 30 to the next span _{S 1} in FIG. 7 (E) ~ FIG 8 (I), as shown in FIG. 6 (B), the rear portion of the next span _{S 1} ChoIzuruketa 11 ₁ is provided with a first temporary PC cable 21 for reinforcement and prestress is introduced, and the span span S _{0 is set} when the bridge girder _3-1 is bridged in the span span S ₋₁ shown in FIG. 6 (A). The first embodiment also includes a point that the first temporary PC cable 21 for reinforcement provided for introducing prestress to the rear overhanging girder 11 is removed after the bridge girder 3 is bridged in FIG. 6C. It is the same.

On the other hand, in this embodiment, when the bridge girder 3 is bridged between the spans S ₀ using the erection girder 30, as shown in FIG. 6C, a plurality of PCa segments 5 are hanger-type erected. The girder connecting portion 16 is constructed by being connected in a state of being hung to 30. Therefore, the plurality of PCa segments 5 in the girder connecting portion 16 can be joined together and the number of joining operations can be reduced, so that the construction period can be shortened.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above-described embodiment, the three support portions 33 are provided on the installation girder 30, but four or more may be provided. In addition, the specific configuration, arrangement, quantity, angle, procedure, and the like of each member and part can be changed as appropriate without departing from the spirit of the present invention. On the other hand, all the components and procedures shown in the above embodiment are not necessarily essential, and can be selected as appropriate.

1 bridge girder 4 stigmas portion 4B rear column capital portion 4F front column capital portion 4F ₁ of the multi-span continuous bridge 2 piers 2B rear piers 2F front pier 2F ₁ primary span _{S 1} of the front pier 3 bridge beam 3 _-1 destination span _{S -1} rear ChoIzuruketa 12 front ChoIzuruketa 13 rear extension digits 14 front extension digits 16 digits connecting portion 21 of the front column capital portion 5 PCa segment 11 rear ChoIzuruketa 11 _primary span _{S 1} of the next span _{S 1} second 1 temporary PC cable 21 _primary span _S first temporary PC cable 22 second temporary PC cable 30 erection girder 33 supporting portion 33F front support supporting portion L1 span length after section 33M in the support portion 33R S span S _{0 1} erection span S _-1 destination span S ₁ primary span

Claims (6)

A bridge girder erection method for a multi-span continuous bridge in which a bridge girder composed of a plurality of PCa segments is erected between each diameter of a plurality of piers arranged with a predetermined span,
A first step of having a plurality of support portions and preparing an installation girder that is longer than the span and shorter than twice the span;
Via the support portion, the rear end of the installation girder is supported by a rear extension girder projecting forward from the rear column head provided on the rear pier between the installation spans, and the intermediate portion of the installation girder is the installation portion A second step of arranging the erection girder at a start position supported by a front column head provided on a front pier between spans;
The PCa segment is arranged using the installation girder, a front overhanging girder projecting rearward from the front column head, and a rear overgirder between next diameters projecting forward from the front column head And a girder connecting portion that connects the rear overhanging girder and the front overhanging girder between the spanning diameters, and the bridge girder is bridged between the rear bridge pier and the front bridge pier between the spanning spans. Steps,
Via the support portion, the rear end of the installation beam is supported by the rear extension beam between the next diameters protruding forward from the front column head, and the intermediate portion of the installation beam is between the next diameters. The bridge girder is erected continuously across a plurality of the spans by repeating the fourth step of moving the erection girder forward to a completion position supported by the front column head provided on the front pier of A bridge girder erection method for multi-span continuous bridges. Before the fourth step, providing a pre-stress by providing a first temporary PC cable for reinforcement in the rear overhanging girder between the next diameters;
For reinforcement provided to introduce prestress in the rear overhanging girder between the spanning diameters when bridging the bridge girder between the front diameters adjacent to the rear side where the bridge girder was previously bridged The method according to claim 1, further comprising a step of removing the first temporary PC cable after the third step.   In the third step, a plurality of the PCa segments are sequentially connected to the rear overhanging girder and the front overhanging girder between the installation diameters by an overhanging construction method, and the girder connection portion is constructed. The bridge girder construction method of the multispan continuous bridge according to claim 1 or 2. The third step includes
Constructing a rear extension beam that protrudes further forward from the rear extension beam between the spans;
Constructing a front extension girder that projects further rearward from the front extension girder and is connected to the rear extension girder,
The fourth step includes
After constructing the rear extension girder, the intermediate part of the installation girder is supported by the front extension girder and the rear extension girder between the next diameters via the support part, and the rear end of the installation girder Moving the erection girder forward to an intermediate position supported by the rear extension girder;
The bridge girder erection method for a multi-span continuous bridge according to claim 3, further comprising the step of moving the erection girder forward from the intermediate position to the completion position after constructing the front extension girder. . The third step includes
A step of introducing pre-stress by providing a reinforcing second temporary PC cable to the rear extension beam before moving the installation beam to the intermediate position where the rear end of the installation beam is supported by the rear extension beam When,
The bridge girder of the multi-span continuous bridge according to claim 4, further comprising a step of removing the second temporary PC cable provided on the rear extension girder after constructing the front extension girder. Construction method.   The said 3rd step connects the said some PCa segment in the state suspended from the said installation girder by the hanger system, and construct | assembles the said girder connection part, The multiple of Claim 1 or Claim 2 characterized by the above-mentioned. Bridge girder construction method of span span continuous bridge.

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