JP2001336117A - Cross section division type precast segment construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To erect the large cross section main girder of large width by a comparatively small-sized precast segment and perform erection working by a normal erection girder or the like in the precast segment construction method of a bridge. SOLUTION: The large cross section main girder of a high bridging or the like is divided into three parts in the orthogonal direction of a bridge axis, and composed of the cross section box type precast core segment 1, a pair of right and left precast embedding forms 2 and a cast-in-place protrusion floor slab 3. A precast member is comparatively small-sized and lightweight, and dispenses with the assembly and disassembly of the form and supporting and the use of the precast floor slab of large weight. The deflection of the protrusion floor slab is suppressed small during construction and after finishing by supporting the protrusion floor slab by a strap frame 4 or the like connecting and integrating a pair of straps or the like by a beam, and handling is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sectional precast segment method for bridges such as viaducts.

[0002]

2. Description of the Related Art In a precast segment method, a precast segment in which a main girder is divided in a bridge axis direction is manufactured in a manufacturing yard or a factory, transported to a construction site by a trailer or the like, and sequentially cast using an erection girder or the like. Joining and erection are performed.

[0003]

However, when constructing a bridge having a large girder and a large cross section, a large and heavy precast segment cannot be transported due to restrictions on road vehicles and the like. There is a problem that the segment method cannot be applied. Also, even if you make a precast segment in the production yard at the site,
There is a problem that a large erection girder or the like is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to enable a large-sized main girder having a large width to be erected by a relatively small-sized precast segment. It is an object of the present invention to provide a cross-section split type precast segment construction method capable of performing construction work with an erection girder or the like.

[0005]

According to the precast segment construction method of the present invention, the main girder segment of the bridge is formed of a center precast core segment, a pair of left and right precast buried formwork and a place-extruded floor. A core segment, and a step of attaching a support member (a strut or bracket made of concrete or steel, etc.) to the outer surface of the core segment (this step can be performed before or after the core segment is installed). )
And a step of laying a precast buried formwork on the support member, and a step of casting a place-extended floor slab on the precast buried formwork.

In the precast segment construction method according to the second aspect of the present invention, the main girder segment of the bridge includes a central precast core segment, a pair of left and right precast buried formwork, and a place-extended floor slab or a precast extended floor slab. And a support frame (a strut frame or bracket made of concrete or steel, etc.) in which a core segment is erected and a support member adjacent to the outer surface of the core segment in the bridge axis direction is connected and integrated with a beam. Process (before or after the core segment is erected), laying a precast buried formwork on this support frame and casting a place-extended floor slab, or precast on the support frame It is characterized by comprising a step of erection of a floor slab.

In the present invention having the above structure, the core segments are sequentially joined and installed by a normal precast segment installation method using an erection girder or the like. According to the first aspect, a support member such as a strut is attached to both sides of the core segment that has been erected in advance, the precast buried form is supported by the support member, and concrete is cast on the precast buried form to place and overhang. Build a floor slab. According to the second aspect, a support frame such as a strut frame is attached to both sides of the core segment that has been erected in advance, the precast buried form is supported by the support frame, and concrete is cast on the precast buried form to cast in place. Build an overhang slab or lay a precast slab on a support frame. In addition,
The support member according to the first aspect and the support frame according to the second aspect can be attached to the core segment before the core segment is erected.

The main girder segment is divided into a place-extended floor slab or a precast-extended floor slab with a central core segment and a pair of left and right precast buried formwork, and the precast member is relatively small and lightweight. It is possible to transport from the production site to the erection site, and erection of the main girder of large section by the precast segment becomes possible. In addition, an erection girder or the like that is used in a normal precast segment erection method can be used.

According to the first aspect of the present invention, since the precast buried formwork is used for the cast-in-place slab, the assembly and disassembly of the formwork and support in the case of using the normal cast-in-place slab is unnecessary, and the precast slab is not required. In the case of using a slab, it is not necessary to transport a heavy slab and use a large lifting machine. According to the second aspect, the support frame in which the struts and brackets adjacent in the bridge axis direction are integrated by beams is used for supporting the overhanging slab, so that the rigidity is enhanced as compared with the case where the struts and the like are individually arranged. Thus, the bending of the overhanging floor slab during and after construction can be suppressed to a small value, and the handling becomes easy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 shows a first embodiment in which a precast buried formwork and a strut frame are used in the sectional split type precast segment method of the present invention. FIG. 2 shows a second embodiment using a precast buried formwork and a bracket of the present invention.
FIG. 3 shows an example of a joint between the core segment and the bracket and a joint between the bracket and the precast buried formwork in FIG. 4 and 5 show a third embodiment using the precast overhang floor slab and the bracket frame of the present invention.

[A] Precast core segment + precast buried formwork + cast-in-place floor slab + strut frame As shown in Fig. 1, in the present invention, a large cross-section main girder of viaduct is divided into three parts in the direction perpendicular to the bridge axis. PC composed of a box-shaped precast core segment 1, a pair of left and right precast concrete buried formwork (PC buried formwork) 2, and a place-extruded floor slab 3, supported by a strut frame 4 made of a precast concrete member. A place-extended floor slab 3 is constructed by casting concrete on the buried formwork 2. The strut frame 4 is not limited to a precast concrete member, but may be a steel pipe, a concrete-filled steel pipe, an H-section steel, or a combination thereof.

The strut frame 4 has a pair of struts 4a, 4a spaced apart in the bridge axis direction and projecting obliquely upward from the outer side of the bottom slab 1b of the core segment 1.
a and a beam 4b for integrally connecting the upper ends of the struts 4a, 4a to form a gate in plan view.

Such strut frames 4 are arranged at predetermined intervals in the bridge axis direction, and a drop-in beam for connecting the beams 4b, 4b between strut frames 4, 4 adjacent in the bridge axis direction. 4c, and the beams 4b and 4c form a continuous support beam in the bridge axis direction. At the joining end of the beam 4b and the beam 4c, engaging stepped portions 10 and 11 are formed, respectively, so that they can be integrally connected. The engaging end 11 of the beam 4c is suspended from above and installed. A shape that can be used.

The floor section 1a of the core segment 1 and the beam 4
b and 4c are arranged at the same level, a step 12 is formed on the outer surface of the floor slab 1a, and a step 13 is formed inside the beams 4b and 4c. To P
The PC embedded mold 2 is supported by placing both ends of the C embedded mold 2 respectively. In addition, the rising surfaces of these steps 12 and 13 also serve as a formwork when concrete is placed on the overhanging slab.

The lower end of the strut 4a is fixed to the outer surface of the bottom slab 1b of the core segment 1 by a joint 5. The joining portion 5 may be a joining structure (described later) shown in FIG. 3A, a joining method using a steel insertion pin and a steel receiving member, or a ball joint method using a steel ball and a steel ball seat. Various joining structures, such as a pin hinge type and a steel pipe insertion type, can be adopted.

At the time of construction, the core segments 1 are sequentially joined and erected by a commonly used precast segment erection method, and the strut frames 4 are attached to the left and right sides of the bottom slab 1b of the core segment 1 on the front end side which has been erected. Beam 4 of this strut frame 4
A PC-embedded formwork 2 is laid between b, 4c and the outside of the floor slab 1a of the core segment 1, and concrete is cast on the PC-embedded formwork 2 to construct an overhanging floor slab 3. I do.

Although not shown, a reinforcing bar or the like is protruded from a joint surface of the floor slab 1a of the core segment 1 and a joint surface of the beams 4b and 4c to the cast-in-place slab 3, and the cast-in-place. Integrate with the overhanging floor slab 3.

In the above-described configuration, by constructing the cast-in-place slab 3 using the PC-embedded form 2, the form-in-place slab in the case of using the normal cast-in-place slab is used.
It is not necessary to assemble or disassemble the shoring, and it is not necessary to transport a heavy slab and use a large lifting machine when using a precast overhang slab. Further, by using the strut frame 4 in which two adjacent struts 4a, 4a are connected and integrated by a beam 4b, rigidity is increased as compared with the case where the struts 4a are individually arranged, and during construction and after completion. Of the overhanging floor slab 3 can be kept small, and handling becomes easy.

The beam 4b of the strut frame 4 is not limited to the example shown in FIG. 1, but may be extended in the bridge axis direction to have a π shape in plan view, and the drop-in beam 4c may be omitted. Also, PCs are provided by individually arranged struts 4a.
The buried form 2 can also be supported. In this case, the upper end of the strut 4a and the lower surface of the PC-embedded formwork 2 are joined by an appropriate joining structure. Further, a precast overhanging slab can be erected on the strut frame 4 instead of the PC embedded formwork 2 and the place overhanging slab 3.

[B] Precast core segment + Precast buried formwork + Place cast floor slab + Bracket As shown in Fig. 2, a bracket 20 made of precast concrete is used in place of the strut, and the base end of the horizontal member 20a is used. The part is joined to the protruding part of the floor slab 1a of the core segment 1 via the filling part 21 such as non-shrink mortar,
The lower end of the diagonal member 20b is joined and fixed to the outer surface of the bottom plate portion 1b of the core segment 1 by the joining portion 5.

Such brackets 20 are disposed at predetermined intervals in the bridge axis direction, and the adjacent brackets 20 and 2 are arranged.
The PC-embedded formwork 2 is laid between 0. Therefore, FIG. 2 (b)
As shown in FIG. 3 (b), below the horizontal member 20a,
A step 22 projecting in the bridge axis direction is provided integrally, and the end of the PC-embedded form 2 is placed thereon. Further, as shown in FIG. 3 (b), the horizontal slab steel member 23 in the direction perpendicular to the bridge axis is
a and the core segment 1 is inserted through the floor slab 1a, and the end is fixed to the outer end of the horizontal member 20a.
0 is fixed while adjusting the angle so that the output of the floor-cast slab 3 can be adjusted.

As shown in FIG. 3 (a), the joining portion 5 has an inverted trapezoidal recess 24 formed in an attachment portion 1c having a substantially triangular cross section and integrally protruding from an outer portion of the bottom plate portion 1b of the core segment 1. The lower end of the diagonal member 20b is inserted into the concave portion 24, and the filling portion 25 is filled in the concave portion 24 with a non-shrink mortar or the like.
Is formed. The lower end surface of the diagonal member 20b has a spherical surface 26, and the inclination angle of the diagonal member 20b can be adjusted by the spherical surface 26 and the concave portion 24, and a construction error can be absorbed. Further, a shearing key 27 is protruded from the side surface at the lower end of the diagonal member 20b and the inner side surface of the concave portion 24 to increase the adhesive strength of the filling portion 25.

In this case, the bracket 20 is not limited to a precast concrete member, but may be a steel pipe, a concrete-filled steel pipe, an H-section steel, or a combination thereof. Also, the bonding portion 5 is not limited to the bonding structure shown in FIG.

At the time of construction, brackets 20 are attached in advance to the left and right sides of the core segment 1, and the core segments 1 are sequentially joined and erected by a commonly used precast segment erection method, and the floor slab steel members 23 are temporarily provided. By tensioning, the angle of the bracket 20 is adjusted, the filling portion 21 is cast, and after the filling portion 21 is hardened, the horizontal slab steel member 23 is fully tensioned, and the adjacent bracket 2
A PC-embedded formwork 2 is laid between 0 and 20 and concrete is cast on the PC-embedded formwork 2 to construct a place-extended floor slab 3. Also in this case, a reinforcing bar or the like is protruded from the joint surface of the floor slab 1a of the core segment 1 and the joint surface of the horizontal member 20a to the place-extended floor slab 3, and integrated with the place-extended floor slab 3. Plan.

Also in this case, by constructing the cast-in-place slab 3 using the PC-embedded formwork 2, assembling / supporting the formwork / support in the case of using the normal cast-in-place slab.
Dismantling is not required, and when a precast overhanging slab is used, transportation of a heavy slab and the use of a large lifting machine are not required.

[C] Precast core segment + precast overhang floor slab (precast buried formwork + place overhang floor slab) + bracket frame As shown in FIGS. 4 and 5, a bracket frame 30 made of steel is used instead of the bracket. Is used. The bracket frame 30 includes a pair of horizontal members 30a, 30a and diagonal members 30b, 30b spaced from each other in the bridge axis direction, and a beam provided at a connection portion between the horizontal member 30a and the diagonal member 30b and extending in the bridge axis direction. 30c to form a π shape in plan view.

Such bracket frames 30 are arranged continuously in the bridge axis direction, and the adjacent bracket frames 3
The zero beam 30c forms a continuous support beam. The beams 30c, 30c can be joined to each other using the beam engaging step shown in FIG. Precast overhanging floor slab 3 'on these beams 30c and horizontal members 30a
Erection.

The bracket frame 30 is shown in FIGS.
As shown in the figure, the lower end of the diagonal member 30b of the bracket frame 30 is joined to the bottom plate portion 1b of the core segment 1 by the joining portion 5.
And fixed to the floor slab 1a of the core segment 1 with a bracket mounting steel material 31 extending in a direction perpendicular to the bridge axis and penetrating through the interior of the horizontal member 30a. As shown in FIG. 4C, for example, a convex plate 32, a concave plate 33, and a taper nut 34 can be used for the fixing portion of the bracket mounting steel material 31.

The floor slab 1a of the core segment 1 and the horizontal member 3
At the joint between the slab 0a and the joint between the floor slab 1a and the precast overhanging slab 3 ', a filling portion 35 made of a reinforcing bar and non-shrink mortar is provided. Also, as shown in FIG. 5 (a), a slip preventing member 3 such as a stud dowel is provided on the beam 30c.
6 are projected and inserted into the mounting holes 37 of the precast overhang floor slab 3 ', and the precast overhang floor slab 3' is fixed to the beam 30c. In addition, the gap between the precast overhanging floor slabs 3 ′ in the bridge axis direction is also provided in the groove at the joint portion.
Is installed.

Further, as the joint 5 between the diagonal member 30b and the floor slab 1b of the core segment 1, for example, a joint structure shown in FIG. 5C can be adopted. This joining structure is such that a steel pipe 40 for joining is embedded in the floor slab 1b of the core segment 1 in advance so that a tip thereof projects a predetermined length, and a wedge is machined by a slit 41 at the tip. The diagonal member 30b is firmly fixed by the wedge effect of the deformed tip. This joining structure is not limited to this,
It goes without saying that other joining methods can be adopted.

The bracket frame 30 is not limited to a steel pipe, but may be a precast concrete member, a concrete-filled steel pipe, an H-section steel, or a combination thereof.

At the time of construction, the core segments 1 are sequentially joined and erected by a commonly used precast segment erection method, and the bracket frames 30 are attached to the left and right sides of the leading-end core segment 1 erected earlier. The precast overhanging floor slab 3 ′ is installed on the bracket frame 30, and the precast overhanging floor slab 3 ′ and the floor slab 1 a of the core segment 1 are fixed by the filling portion 35.

Also in this case, by using the bracket frame 30 in which two adjacent brackets are connected and integrated by a beam, rigidity is increased as compared with a case where brackets are individually arranged, and during construction and after completion. The bending of the precast overhang floor slab 3 'can be suppressed to a small value, and the handling becomes easy. Further, by forming the bracket frame 30 in a π shape in plan view, the drop-in beam in FIG. 1 can be omitted.

In the example shown in FIG. 4, the case of the precast overhanging floor slab 3 'is shown, but it is needless to say that the present invention can also be applied to the PC embedded formwork 2 and the place overhanging floor slab 3.

[0035]

Since the present invention has the above-described configuration, the following effects can be obtained.

(1) The main girder segment is divided into a place-extended floor slab or a precast-extended floor slab with a center core segment and a pair of left and right precast buried formwork, and the precast member is relatively small and lightweight. It is possible to carry from the production site to the erection site, and it becomes possible to erection of the main girder of large section by the precast segment.

(2) As the erection girder, the one used in the ordinary precast segment erection method can be used, and the cost can be reduced.

(3) By using the precast buried formwork for the place-casting slab, it is not necessary to assemble and disassemble the formwork and support work when using the normal place-casting slab. When it is used, a heavy floor slab and a large lifting machine are not required, thereby shortening the construction period and reducing costs.

(4) By using a support frame in which struts and brackets adjacent in the bridge axis direction are integrated by beams for supporting the overhanging slab, the rigidity is higher than when struts and the like are individually arranged. , The bending of the overhanging slab during and after construction can be suppressed to a small level, and the handling becomes easy, and the construction efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a divided-section type precast segment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of a precast segment according to the present invention, in which (a) is a front view and (b) is a perspective view.

3A is a cross-sectional view showing an example of a joint portion between a core segment bottom plate and a lower end of a bracket in FIG. 2, and FIG.
It is sectional drawing which shows an example of the junction part of a PC embedding formwork and a cast-in-place beam slab and a bracket in FIG.

FIGS. 4A and 4B show a third embodiment of a divided-section precast segment of the present invention, wherein FIG. 4A is a front view, FIG.
(c) is a sectional view showing a fixing part of the steel material.

FIG. 5 is a third embodiment of a cross-section precast segment of the present invention, (a) is a perspective view, (b) is a side view,
(c) is a cross-sectional view showing a joint portion of the oblique material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Precast core segment 1a ... Core segment floor slab part 1b ... Core segment bottom slab part 1c ... Attachment part 2 ... Precast embedding formwork 3 ... Place overhang floor slab 3 '... Precast overhang floor slab 4 ... Strut frame 4a ... strut 4b ... beam 4c ... drop-in beam 5 ... ... joint part between core segment bottom plate part and strut etc. 10 ... beam engagement step part 11 ... beam engagement step part 12 ... core segment step Part 13: Step portion of beam 20: Bracket 20a: Horizontal member 20b: Diagonal member 21: Filling portion 22: Step portion of bracket 23: Floor slab steel member 24: Recess 25: Filling Part 26: spherical surface 27: shear key 30: bracket frame 30a: horizontal member 30b: diagonal member 30c: beam 31: bracket mounting Material 32 ...... convex plate 33 ...... concave plate 34 ...... taper nut 35 ...... between filling unit 36 ...... displacement preventing member 37 ...... mounting hole 40 ...... steel pipe 41 ...... slit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takehiro Nishiko 2-19-1, Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute F-term (reference) 2D059 AA08 AA14 CC03 DD16 GG55

Claims (2)

[Claims] 1. A main girder segment of a bridge comprises a central precast core segment, a pair of left and right precast buried formwork and a place-extruded floor slab, a step of erection of the core segment, and an outer surface of the core segment. A step of mounting a support member on the support member, a step of laying a precast buried formwork on the support member, and a step of casting a place-extended floor slab on the precast buried formwork. Precast segment method. 2. A main girder segment of a bridge comprising a central precast core segment, a pair of left and right precast buried formwork and a place-extruded floor slab or a precast slab, and a step of erection of the core segment; A process of attaching a support frame formed by connecting and integrating support members adjacent in the bridge axis direction with beams on the outer surface of the core segment, and laying a precast buried formwork on the support frame and striking a place slab. Installing or laying a precast floor slab on a support frame.