JP2004285738A - Box girder bridge structure and method of constructing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a box girder bridge structure which allows its upper floor slabs, and lower floor slabs if necessary, to be easily, quickly and inexpensively constructed only by employing forms borne by a simplified form bearing device by using truss girders, and to provide a method of constructing the box girder bridge structure. <P>SOLUTION: According to the box girder bridge, a box girder serving as a web is formed of the truss girder 17 consisting of a plurality of precast concrete web units 2 each formed of precast concrete members 1, and the plurality of truss girders 17 are employed to be erected astride piers or abutments 23 adjacent to each other in a bridge axial direction. Then the upper floor slab 41, and the lower floor slab 40 if necessary, are constructed by pouring cast-in-place concrete in a gap between the two truss girders 17 adjacent to each other via the gap in a direction intersecting the bridge axial direction, so that the truss girders are combined together in one body. Then outer cables 36 are strained and anchored to the truss girders 17 or transverse girders 31 extended astride edges of the truss girders, at both ends in the bridge axial direction, and then tensile force is introduced to the cables. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a box girder bridge structure and a construction method thereof.
[0002]
[Prior art]
Conventionally, when constructing a relatively large bridge in a concrete bridge or the like, the torsional rigidity is extremely large as compared with the girder of the I-shaped cross section, which is advantageous for a main girder of a curved bridge, and the girder height can be designed low, Box girder bridges have been adopted for long span bridges and when the space under the girder is very limited.
[0003]
When constructing a box girder, (1) assembling the shoring and then performing cast-in-place construction on it, or (2) constructing a box girder on the back of the abutment, as in the extrusion method. (3) In some cases, a box girder is constructed one segment at a time using a mobile erection machine (for example, see Patent Document 1).
[0004]
However, in the above (1), if the space under the girder cannot be secured, it cannot be applied, and in the above (2) and (3), a large-scale erection material or a large-scale erection device is required, and the construction cost increases. Become.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-4225
As a construction method to improve these points, the box girder method of erection of the girder, then building the upper slab and, if necessary, the lower slab with cast-in-place concrete and integrating it, and finally tensioning and fixing the outer cable, has already been implemented. It has been filed by the present applicant (Japanese Patent Application No. 2000-355038).
[0007]
In the above invention, when the girder as the web material is small span, the box girder structure is excellent as a form capable of constructing a large bridge without using large erection facilities, but the girder as the web material is large span and heavy weight In such cases, large erection facilities are required. In addition, when a girder as a web material has a large span, a bridge type in which the web material is further reduced in weight is demanded from the viewpoint that a large construction yard is required and the cost is increased.
[0008]
[Problems to be solved by the invention]
The present invention provides a bridge that can be reduced in weight even if the girder has a large span by making the portion of the box girder that corresponds to the web a lightweight girder. The upper floor slab and the lower slab can be constructed easily and quickly at low cost with only the formwork supported by the simple formwork supporting device using the girder, without using materials or large erection equipment. It is an object of the present invention to provide a box girder bridge structure having a simple structure and a construction method thereof.
[0009]
[Means for Solving the Problems]
In order to advantageously solve the above-mentioned conventional problems, in the box girder bridge structure of the first invention, in the box girder bridge, a girder to be a web by the box girder is replaced by a plurality of truss structures having a precast concrete member. A truss girder using a web unit made of precast concrete, and using a plurality of the truss girder, these are erected over piers or abutments adjacent in the bridge axis direction and are spaced apart in a direction intersecting with the bridge axis direction. Between the two truss girders, the upper slab and, if necessary, the lower slab are constructed from cast-in-place concrete and integrated, and an external cable is arranged, and the external cable is connected to the truss girder or their ends. It is characterized in that tension is fixed to the cross beams at both ends in the bridge axis direction provided over the portion, and tension is introduced.
[0010]
According to a second invention, in the box girder bridge structure of the first invention, the precast concrete web unit includes a precast concrete hollow member in which a PC steel material is embedded, and a side integrated with the precast concrete hollow member. A unitized member including a top floor slab and a side bottom slab, wherein the PC steel material is fixed to the side top slab and the side bottom slab.
[0011]
According to a third aspect of the present invention, in the box girder bridge structure of the first or second aspect, the truss girder is configured by connecting a plurality of precast concrete web units, which are blocks, constituting the truss girder. Matching precast concrete web units are characterized by being integrated with adhesive and PC steel.
[0012]
According to a fourth invention, in the box girder bridge structure according to any one of the first to third inventions, a PC steel material arranged on a web portion of the truss girder and a PC steel material arranged on a side lower slab as a lower chord material. It is characterized by having a structure capable of holding the bridge's own weight by using steel, and having a structure that bears a bridge surface load and a live load with an external cable.
[0013]
According to a fifth aspect of the present invention, in the method of constructing a box girder bridge, a girder forming a web by the box girder is formed by using a truss girder connecting a plurality of precast concrete web units, and connecting these with a pier or an abutment in the bridge axis direction. After erection, the upper slab and, if necessary, the lower slab are integrated with cast-in-place concrete between the two adjacent girders spaced apart in the direction intersecting with the bridge axis direction, and the outer cable is connected. A method of constructing a box girder bridge characterized by arranging the outer cable and tensioning and fixing the outer cable to the girder or the horizontal girder at both ends in the bridge axial direction provided across these ends, and introducing tension. is there.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in detail based on the illustrated embodiment.
[0015]
FIGS. 1 and 2 show a precast concrete web unit 2 made of a precast concrete member 1 for forming a truss girder used in a box girder bridge structure and a method for constructing the same according to the present invention. 1 (a) is a side view, (b) is a front view, FIG. 2 (a) is a partially longitudinal side view, and (b) is a plan view.
[0016]
As shown in FIG. 1 and FIG. 2, the precast concrete web unit 2 is a blocked unit for forming the web of the truss, and is a side upper floor slab which constitutes a part of the upper slab when the bridge is completed. 3 and the upper ends of a pair of precast concrete members 1 as diagonal members constituting a truss arranged in the same vertical plane in a mountain shape (substantially inverted V-shape). Is joined to a lower side slab 4 constituting a part of the lower slab when the bridge is completed. The precast concrete web unit 2 is a member having a truss structure when viewed from the side, having a substantially H-shaped front surface.
[0017]
For example, as shown in FIG. 11, the precast concrete member 1 is a hollow precast concrete member having a circular cross section such as a PC pile and the like, in order to reduce the weight of the bridge, and has an annular shape of the precast concrete member body 1a. PC steel material 6 is embedded in the peripheral wall portion 5 so as to be spaced apart in the circumferential direction and extended in the axial direction, and is arranged so as to protrude the PC steel material 6 from both ends of the precast concrete member main body 1a. is there.
[0018]
When the above-mentioned precast concrete member 1 is manufactured, it is manufactured by centrifugal molding or the like, and a tensioned PC steel material (not shown) is embedded and arranged over the entire length or a part thereof, and also protrudes from the end side. A PC steel material 6 for joining is provided. The steel pipe sheath 1b may be embedded and arranged inside the precast concrete member 1.
[0019]
The side upper slab 3 and the lower side slab 4 are arranged on a factory or a site yard by disposing the precast concrete member 1 at a predetermined position and arranging the side upper slab 3 and the side lower slab 4. After the rebar work, concrete is filled and hardened so that the end side of the precast concrete member 1 is buried in the concrete portion at the point, and each PC steel material 6 in the precast concrete member 1 is connected to the concrete side portion. The pre-cast concrete web unit 2 in which the precast concrete members 1, the side upper slabs 3 and the side lower slabs 4 are integrated is manufactured by being tensioned and fixed to the upper slab 3 and the lower side slab 4.
[0020]
Although not shown in the drawing, the end face in the bridge axis direction of the side upper deck 3 and the side lower deck 4 and the reinforced concrete portion formed integrally therewith in the bridge axis direction, i. ) Is provided to prevent vertical displacement and shear reinforcement with the adjacent precast concrete web unit 2.
[0021]
The upper graded portion 7 at the apex serving as a portion for joining the precast concrete members 1 having the above-mentioned chevron arrangement is firmly formed by the upper graded portion reinforced concrete 8 integrally provided on the side upper floor slab 3 serving as the upper chord material. The lower graded portion 9 which is integrated with the side upper floor slab 3 and which joins the lower end of each of the precast concrete members 1 in the above-mentioned chevron arrangement is provided integrally with the side lower floor slab 4 serving as the lower chord material. The lower graded reinforced concrete 9a is firmly integrated with the side lower slab 4. Through holes 10 extending in the bridge axial direction (front-rear direction) are previously embedded in the lower graded portion reinforced concrete 9a in parallel with a sheath or the like in parallel with an interval in the left-right direction (direction intersecting with the bridge axis direction). In addition, a bearing member 11 made of steel or the like is embedded and arranged at the end of the through hole 10 in the lower reinforced concrete portion 9a on the inner side of each of the precast concrete members 1 opposed to each other. A step having a vertical supporting wall 12 made of PC steel is formed.
[0022]
The side lower slab 4 has a plurality of (four in the illustrated case) PC steel insertion holes 13 penetrating at both ends in the bridge axis direction at intervals in the left-right direction and extending in the bridge axis direction. A fixing unit is provided on the end side of the web unit 2 made of precast concrete, which is arranged on the end side although not shown. The lateral upper floor slab 3 and the side lower floor slab 4 may be provided with a lateral tightening PC steel material insertion hole 14 by embedding a sheath or the like for horizontal tightening in advance in a direction perpendicular to the bridge axis. .
[0023]
After the concrete is cast on both ends of the precast concrete member 1 to construct the side upper slab 3 and the side lower slab 4, the PC steel 6 for joining is removed when a predetermined strength is obtained. Then, the side upper slab is inserted into the side upper slab 3, the upper graded concrete 8, the precast concrete member 1, the lower graded concrete 9a, and the side lower slab 4 in advance through a sheath which is embedded and tensioned. It is also possible to fill in the recesses at the end of the lower slab 3 and the side lower slab 4.
[0024]
When joining the precast concrete web units 2 configured as described above to each other, a plurality of precast concrete web units 2 are set on a girder joining stand (not shown) at the site, The front-rear, left-right, and up-down three-dimensional positions are adjusted, and an adhesive 15 is applied to the longitudinal end face of the precast concrete web unit 2 in the bridge axis direction, and the other precast concrete web unit 2 is connected to the bridge shaft. Then, the web units 2 made of precast concrete are bonded to each other as shown in FIG.
[0025]
In addition, the adjacent lower concrete part 9a is tensioned by the joining PC steel material 16 inserted therein, and the ends thereof are supported by the supporting member 11 and are fixed by the fixing metal, and the precast concrete web units 2 are connected to each other. Joining and repeating such a process to form a truss girder 17 having a predetermined length, and inserting a PC steel material 18 into each PC steel material insertion hole 13 in the side lower slab 4 as shown in FIG. The truss girder 17 is fixed at the end of the truss girder 17 while being inserted.
[0026]
A pair of truss girders 17 similar to the above may be constructed, and bearings 20 may be attached to the ends of these truss girders 17 as shown in FIG. The truss girder 17 configured as described above is a truss girder 17 capable of sufficiently retaining the weight of the truss girder 17 by a plurality of PC steel materials 18 arranged and tensioned on the side lower slab 4. In the present invention, the truss girder 17 configured as described above is used as a web material for a box girder.
[0027]
The lateral upper floor slab 3 and the side lower floor slab 4 project laterally in the left-right direction (rightward from the right end of the precast concrete web unit 2 shown in FIG. 1B) which is perpendicular to the bridge axis. There is a floor slab for joints, but it is omitted in the drawing.
[0028]
The shape of the truss girder 17 viewed from the bridge axis direction may be an inverted T-shape or an I-shape, but the post-construction upper slab between the side upper slabs 3 and the post-construction lower slab between the side lower slabs 4 at the site. Considering the construction, the H-shape is more rational, and the stability is better when a truss girder is erected. Note that a bearing device may be installed on the pier (or abutment) 23 in advance.
[0029]
<Construction procedure>
Next, the construction procedure of the box girder bridge structure of the present invention and the construction method thereof will be described using the truss girder 17 manufactured in advance as described above.
[0030]
First, the joined precast concrete truss girders 17 are spaced apart in the direction perpendicular to the bridge axis (left and right direction) using a girder or a wrecker (not shown) installed on the pier (or abutment) 23. (Or abutment) 23 (see FIG. 4). The web portion of the box girder 46 is erected by installing the truss girder 17 in accordance with the lower shoe attached to the abutment (or abutment) 23. When the truss girder 17 has been erected, a hanging scaffold (not shown) is assembled.
[0031]
A large number of H-shaped steels are arranged in the bridge axis direction as spacers 24 over the adjacent truss girders 17 at intervals in the direction intersecting with the bridge axis direction (see FIG. 6). The H-section steel as the spacer 4 is not always necessary and is not shown, but a through-hole is previously provided in the side upper floor slab 3 (or the side lower floor slab 4) of the truss girder 17, and the hanging screw rod is used. By suspending and supporting the steel rod, the suspended steel rod may be used to suspend and support the form support and the form supported by the formwork, or not shown, The formwork may be supported by screwing a form-hanging steel rod to an insert previously embedded in the side upper floor slab 3 (or the side lower floor slab 4).
[0032]
Form support beams 28 such as H steel or die steel are passed as support members on the spacers 24 made of H steel on both the precast concrete truss girders 17 and temporarily fixed with appropriate bolts or appropriate temporary fasteners. I do. The form support beam 28 is not always necessary as described above. In this embodiment, the formwork supporting beam members 28 may be arranged at intervals that can be reduced by the weight of the concrete floor 34. In this way, the upper part of the form suspending material 29 is locked by the nut 43 to the form supporting beam 28 passed over the truss girder 17 made of precast concrete, and the form suspending material 29 is suspended and supported. I do.
[0033]
In order to lock the upper part of the form hanging material 29 to the form supporting beam 28, the form supporting beam 28 is provided with a bolt hole (in the case shown) or a female screw hole. Then, the upper part of the form hanging material 29 is formed in a hook shape.
[0034]
The form receiving members 30 are arranged so as to be supported by the hanging members 29, and form forms 39 for the upper deck and the lower deck are assembled (see FIG. 6 or 7a). In addition, a formwork (not shown) of the end horizontal beam 31 and the intermediate horizontal beam 32 is also assembled. Although not shown, a bridge prevention device, a fixing device for an outer cable, a sheath, a sheath for lateral tightening, a steel material, and the like are arranged on the end cross beams 31. Further, a sheath for horizontal tightening and a steel material are also arranged on the intermediate horizontal girder 32.
[0035]
Reinforcing bars and a sheath for horizontal tightening (PC steel material is inserted) 33 are arranged on each floor slab and horizontal beam, and concrete 34 is cast.
[0036]
When the concrete 34 reaches a predetermined strength, the laterally tightened PC steel 35 is tensioned and settled, and the upper floor slab 41 and the lower floor slab 40 integrated with the side upper floor slabs 3 and the side lower floor slabs 4 are constructed. (See FIG. 8).
[0037]
Next, the outer cable 36 is arranged. A protective tube 44 made of synthetic resin or steel is passed through the deviator portion of the intermediate cross beam 32 so as not to be damaged. A fixing device 37 of a wedge type or the like is attached to the end of the end cross beam 31, and the outer cable 36 is tensioned to introduce prestress and fix (see FIGS. 9 and 12). By arranging the outer cable 36 in this manner, the outer cable can bear a bridge surface load and a live load.
Grout is performed between the laterally tightened PC steel 35 and the sheath. After that, the support such as the formwork and the hanging support member is dismantled.
[0039]
As described above, in the present invention, after the truss girder 17 is erected on the pier (or abutment) 3, a member for supporting the formwork is merely installed on the truss girder 17, and a large-scale erection material or Since the truss girder 17 can be used only with a form supported by a simple form supporting device without using a large erection device, the upper and lower floor slabs (upper slab and lower slab if necessary) can be used. Can be easily, quickly and at low cost. Further, since the construction is also simplified, the construction is simple, and the process is simple, so that the construction can be performed quickly and the construction period can be shortened.
[0040]
Further, the truss girder 17 to be initially bridged only needs to be able to bear its own weight and the load when the floor slab is subsequently constructed. Furthermore, if the upper and lower side floor slabs 3 and 4 are provided to improve the stability at the time of erection, the amount of the floor slab 34 to be subsequently cast on site can be reduced.
[0041]
When implementing the present invention, the lower slab 40 may be constructed, and then the upper slab 41 may be constructed and constructed. Then, the bridge surface load and the live load may be mainly borne by introducing the prestress of the outer cable 36.
[0042]
As described above, in the present invention, the weight of the bridge is maintained by the PC steel material 16 arranged in the web portion of the truss girder 17 and the PC steel material 18 arranged in the side lower slab 4 as the lower chord material. The structure is such that the outer cable 36 bears the bridge surface load and the live load.
The box girder 46 does not need to be provided with the lower slab 40 if the truss girder 17, the upper slab 41 and the external cable 36 alone are used depending on conditions. Therefore, the lower deck 40 may be provided as needed. The height of the truss girder 17 is appropriately set.
[0043]
In the case of the above embodiment, the intermediate horizontal beam 32 is used as a deviator. In practicing the present invention, although not shown, a deviator may be provided on the upper surface of the lower floor slab 40 without providing the intermediate cross beam 32.
[0044]
Further, when the present invention is carried out, although not shown, the lower floor slab 40 may be provided only on the end side of the truss girder 1 in the bridge axis direction.
[0045]
In the case of the above-described embodiment, the end cross beam 31 is constructed over the end of the truss girder 17 and the outer cable 36 is fixed to the end cross girder 31. Alternatively, both ends of the outer cable 36 may be fixed to the truss beam 17 by providing an outer cable fixing portion projecting from the outer cable 36.
[0046]
In practicing the present invention, although not shown, when constructing the lower floor slab 40 or the upper floor slab 41, the precast concrete buried plate may be used as a formwork to cast the concrete 34. Good.
[0047]
As in each of the above embodiments, a large number of support beams are erected over the upper portions of the two truss girders 17, and a mold for the lower floor slab or a mold for the upper floor slab is provided via the support beams. Supporting a frame or providing a large number of hanging support fittings on two girders, and supporting the formwork for the lower floor slab or the formwork for the upper floor slab by these hanging support fittings, is relatively large. Since it is not necessary to arrange the equipment on a precast concrete truss girder, the upper and lower floor slabs can be easily, quickly, and inexpensively constructed using only the form supported by the simple form support device using the truss girder. .
[0048]
【The invention's effect】
According to the box girder bridge structure of the first invention, in the box girder bridge, the girder to be a web by the box girder is a truss girder using a plurality of precast concrete web units of a truss structure provided with a precast concrete member. Using the truss girders, these are erected over the piers or abutments adjacent in the bridge axis direction, and the upper deck and the necessary In response, the lower slab is constructed of cast-in-place concrete and integrated, and an outer cable is arranged, and the outer cable is provided next to the truss girder or both ends in the bridge axial direction provided over these ends. Since the girder is tensioned and tension is introduced, even a relatively large span truss girder can be used as a large span and lightweight box girder using a lightweight truss girder. The structure is simple, it can be a box girder bridge that can be applied by easily and quickly at low cost.
[0049]
Particularly, in the present invention, since a truss girder using a plurality of precast concrete web units having a truss structure provided with precast concrete members is used, even in a relatively narrow construction yard, a short span precast concrete web unit can be used. It can be easily manufactured at low cost.
[0050]
Further, as in the second invention, the precast concrete web unit includes a precast concrete hollow member in which a PC steel material is embedded, and a side upper deck and a side lower deck integrated with the precast concrete hollow member. As a unitized member, when the PC steel material is fixed to the side upper slab and the side lower slab, a precast concrete hollow member, and a side upper slab or a side lower slab for on-site construction. Can be easily integrated, and a light-weight truss girder can be further reduced in material cost, so that a lighter and lower-cost box girder can be obtained.
[0051]
As in the third invention, a truss girder is formed by connecting a plurality of precast concrete web units, which are block members, constituting the truss girder, and the precast concrete web units adjacent in series are bonded to each other by an adhesive and a PC steel material. When integrated, the precast concrete web units can be easily connected and integrated.
[0052]
As in the fourth invention, the PC steel material disposed on the web portion of the truss girder and the PC steel material disposed on the side lower slab as the lower chord have a structure capable of holding the weight of the bridge, and If the external cable is designed to bear the bridge surface load and live load, the truss girder can be held without holding the external cable on the truss girder. The construction and construction of the floor slab are easy, and the PC steel material arranged in the truss girder and the external cable can be shared, so that economical design is possible.
[0053]
According to the fifth invention, the girder which becomes the web by the box girder is a truss girder connecting a plurality of precast concrete web units, and after this is erected, a large-scale erection material or a larger erection device is used. The upper deck and the lower deck can be constructed easily and quickly at low cost using only the formwork supported by the simple form support device using the truss girder. However, a light box girder can be obtained. In addition, a lightweight box girder bridge that uses an external cable by simply fixing the external cable to the truss girder or the horizontal girder at both ends in the bridge axial direction provided across these ends and introducing tension. Can be easily constructed.
[Brief description of the drawings]
1 shows an embodiment of a web unit made of precast concrete used in the present invention, wherein (a) is a side view and (b) is a front view.
2 (a) is a partially longitudinal side view of FIG. 1 (a), and FIG. 2 (b) is a plan view.
FIG. 3 is a side view showing a connection between end faces of web units made of precast concrete and a connection between lower concrete points.
4A and 4B show a state in which a box girder bridge is constructed by implementing the present invention, wherein FIG. 4A is a schematic longitudinal sectional front view showing a state in which a truss girder is erected on a pier, and FIG. It is a top view.
FIG. 5 is a partial cross-sectional plan view showing a PC steel material that is disposed over the entire length of the side lower slab of each precast concrete web unit and is set and tensioned.
6 (a) shows a state in which a number of formwork supporting beams are installed on adjacent truss girders with spacers interposed on the truss girders from the state of FIG. 4 to support the formwork for the lower slab. FIG. 2B is a schematic plan view.
7A is a longitudinal sectional front view showing a state in which an upper slab is being constructed after the lower slab is constructed from the state of FIG. 6, and FIG. 7B is a state in which an upper slab is constructed from the state of FIG. And (c) is a longitudinal sectional front view showing the vicinity of an end portion of a lateral girder of the outer cable.
FIG. 8 is a vertical sectional front view showing a state where left and right truss girders and each floor slab are laterally tightened after an upper floor slab and a lower floor slab are constructed.
9A is a schematic side view showing a completed state, and FIG. 9B is a schematic plan view of FIG. 9A.
FIG. 10 is a vertical sectional front view showing an example of a truss girder used in the present invention.
FIG. 11 is a longitudinal sectional front view showing a precast concrete member used as a truss diagonal member in the precast concrete web unit.
12A is a vertical side view showing an outer cable fixing portion in an end horizontal girder, and FIG. 12B is a vertical side view showing a relationship between an intermediate horizontal girder and an outer cable.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Precast concrete member 1a Precast concrete member main body 2 Precast concrete web unit 3 Side upper floor slab 4 Side lower floor slab 5 Annular peripheral wall 6 PC steel 7 Upper grade 8 Upper grade concrete 9 Lower grade 9a Lower Girder concrete 10 Through hole 11 Bearing member 12 Bearing vertical wall 13 PC steel material insertion hole 14 PC steel material insertion hole for lateral tightening 15 Adhesive 16 PC steel material 17 for joining 17 Truss girder 18 PC steel material 20 Bearing 23 Bridge pier (or abutment)
24 Spacer 28 Formwork support beam 29 Formwork suspending material 30 Formwork receiving material 31 End crossbeam 32 Intermediate crossbeam 33 Sheath 34 for lateral tightening Concrete 35 Lateral tightening PC steel material 36 Outer cable 37 Fixing tool 38 Suspended steel rod 39 Formwork 40 Lower deck 41 Upper deck 43 Nut 44 Protection tube 46 Box girder

Claims (5)

In a box girder bridge, a girder that becomes a web by a box girder is a truss girder using a plurality of precast concrete web units having a truss structure provided with a precast concrete member, and a plurality of the truss girder is used. An upper deck and, if necessary, a lower deck are constructed of cast-in-place concrete between the two adjacent truss girders spanning the pier or abutment adjacent in the axial direction and spaced apart in a direction intersecting with the bridge axis direction. The outer cable is tensioned and fixed to the truss girders or the cross beams at both ends in the bridge axis direction provided over the ends thereof, and tension is introduced. Box girder bridge structure characterized by the fact that it is. The precast concrete web unit is a unitized member including a precast concrete hollow member in which a PC steel material is embedded, and a side upper slab and a side lower slab integrated with the precast concrete hollow member. The box girder bridge structure according to claim 1, wherein the PC steel material is fixed to the side upper slab and the lower side slab. The truss girder is formed by connecting a plurality of precast concrete web units which are block members constituting the truss girder, and the precast concrete web units adjacent in series are integrated by an adhesive and a PC steel material. The box girder bridge structure according to claim 1 or 2, wherein: The truss girder has a structure in which the weight of the bridge can be maintained by the PC steel material arranged on the web portion and the PC steel material arranged on the side lower slab as the lower chord material, and the bridge surface load with an external cable. The box girder bridge structure according to any one of claims 1 to 3, wherein the box girder bridge structure is configured to bear a live load. In the method of constructing a box girder bridge, a girder that becomes a web with a box girder is erected using a truss girder connecting a plurality of precast concrete web units over a pier or an abutment adjacent in the bridge axis direction, An upper floor slab and, if necessary, a lower slab are constructed from cast-in-place concrete and integrated between the two girders adjacent to each other at a distance in a direction intersecting with the bridge axis direction, and an outer cable is arranged. A method of constructing a box girder bridge, wherein an outer cable is tensioned and fixed to a girder or a horizontal girder provided at both ends in a bridge axial direction provided over these ends, and a tension is introduced.

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