JP2009221714A - Composite girder bridge of prestressing steel concrete, and its erection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite girder bridge of prestressing steel concrete, which is economically more advantageous than a main girder bridge using only a small amount of steel. <P>SOLUTION: A concrete flange 13 integrated with a corrugated steel web 11 is formed at the upper end of the corrugated steel web 11, the lower end of which is fitted with a steel flange 12, so as to manufacture a precast concrete bridge girder segment 100; a precast concrete bridge girder segment 101, in which the two precast concrete bridge girder segments 100 are connected together by field assembling, is sequentially erected between an abutment 21 and a bridge pier 22 by erection with stagings or girder erection; end surfaces of the concrete flanges 13 between the respective precast concrete bridge girder segments 101 abut on each other; the corrugated steel webs 11 are connected together; the steel flange 12 is connected in the direction of a bridge axis, and supported as a simple girder between the abutment 21 and the bridge pier 22; and after the construction of an upper floor slab 23, prestress is introduced into a girder bridge between the abutment 21 and the bridge pier 22 by means of an outer cable 30 in the direction of the bridge axis of a bridge. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a PC steel-concrete composite girder bridge and its erection method. More specifically, the present invention relates to a bridge having a span of about 40 m to 60 m, having a corrugated steel web, and synthesizing cast-in-place concrete slab or precast PC slab. The present invention relates to a PC steel concrete composite girder bridge and its erection method.

  In a conventional concrete T girder using corrugated steel plates for the web, the upper and lower flanges were made of concrete, so the weight was heavy. In addition, since it is necessary to introduce a large degree of compressive stress to the lower flange, a large amount of prestress is required, and it resists the degree of compressive stress immediately after introduction caused by introducing a large amount of prestress. For this reason, a large lower flange is required, which increases the weight.

  Furthermore, in the T-girder using the corrugated steel web, when joining the girder of the precast segment structure, it is necessary to set the stress level of the joint part to a full pre-stress state, which is a structural weak point. In addition, in order to fix a large capacity PC steel material at the end of the girder, it is necessary to bend and arrange it, which causes a weight increase because the concrete is wound up.

  For bridges with a span of about 40 to 60m, some designers consider that the steel minority girder bridge is more advantageous in design than the conventional corrugated steel web T-girder. In some cases, steel minority girder bridges are used.

  However, the conventional steel girder uses a lot of expensive steel because the upper flange of the steel girder is responsible for a large compressive force. Moreover, although the web uses a flat steel plate, in order to stiffen against buckling, it is necessary to attach many vertical stiffeners and horizontal stiffeners by welding.

  When prestressing is applied to a conventional steel girder, the vertical web is restrained and prestress is not introduced into the main girder. Since the upper floor slab is usually made of concrete, it is difficult to join with the steel flange, and many of them have a non-synthetic structure. In the case of a synthetic structure, it was necessary to melt many studs, and there was difficulty in joining with a precast slab.

  There is a steel-concrete composite girder having a steel flange at the lower end of the steel web and a reinforced concrete flange at the upper end (see, for example, Patent Document 1).

This girder is a simple girder that has a small girder height, uses flat steel plates for the web, and spans between small and medium branches, and forms a bridge surface by laterally tightening reinforced concrete flanges.
Japanese Patent Laid-Open No. 2007-126913

  The present invention improves a concrete girder using a corrugated steel web, and in a bridge having a span of about 40 to 60 m, a novel PC steel concrete composite girder bridge that is economically advantageous compared with a steel minority main girder bridge and its The purpose is to provide a construction method.

  The present invention has been made in order to solve the above-mentioned problems. The technical means includes a steel flange at the lower end of the corrugated steel sheet web, and a concrete flange integrated with the upper end of the corrugated steel sheet web at the upper end. This is a PC steel concrete composite girder bridge characterized in that an outer cable is stretched in the direction of the bridge axis.

  The PC steel-concrete composite bridge girder according to the present invention uses a corrugated steel plate for the web, so that it is resistant to buckling and is easy to introduce prestress in the girder axis direction. In the present invention, since the lower flange of the corrugated steel sheet web is made of steel, the weight of the girders can be reduced as compared with a conventional bridge girder whose upper and lower flanges are made of concrete. This steel flange and corrugated steel web are joined by welding.

  Such a PC steel concrete composite girder bridge can be realized by the following means. That is, the method of the present invention produces a precast concrete bridge girder segment by forming a concrete flange integral with the corrugated steel sheet web at the upper end of a corrugated steel sheet web having a steel flange attached to the lower end, and the precast concrete bridge girder segment is vented or installed. The girder is installed between the piers in sequence, the concrete flange end faces between each precast concrete bridge girder segment are brought into contact, the corrugated steel web is joined, the steel flange is joined in the direction of the bridge axis, and the bridge girder is a simple girder between the piers. After the construction of the upper floor slab, prestress is introduced into the bridge girder between the piers using an external cable in the bridge axis direction of the bridge.

  In the erection method of the present invention, the steel flange provided at the lower end of the corrugated steel sheet web is prestressed in the direction of the bridge axis by the outer cable after a tensile force is generated by its own weight.

  Bonding of the concrete flange at the upper end of the corrugated steel web has a precast segment structure, but since it is always compressed, there is no disadvantage in structure.

  Since the upper flange of the corrugated steel sheet web is concrete, it has good bondability with the upper floor slab concrete, and it is easy to have a composite structure with gibber bars by reinforcing bars.

  In the construction method of the present invention, when there are a plurality of spans, the bridge girders may be continuous, and prestress may be introduced into the bridge girders using an external cable arranged in the bridge axis direction across the plural spans. In the continuous girder structure spanning a plurality of diameters, by appropriately arranging the outer cable, the tension at the upper edge of the intermediate fulcrum and the compressive stress at the lower edge are improved by the prestress secondary force.

  According to the present invention, the weight can be reduced by making the lower flange made of steel, and by using the corrugated steel sheet web, it is easy to introduce prestress against buckling. Further, since the pre-stress is applied after the tensile force is generated on the lower flange by its own weight, the lower flange is not easily buckled.

  In addition, since the upper flange is concrete, it is easy to join with the upper floor slab concrete, and it is easy to have a composite structure with the dowel bars.

  Further, by appropriately arranging the outer cable in the continuous girder structure, the tensile stress at the upper edge of the intermediate fulcrum and the compressive stress at the lower edge are improved by the prestress secondary force.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view of a PC steel concrete composite girder bridge 1 according to an embodiment of the present invention, and FIG. 2 is a plan view of the PC steel concrete composite girder bridge 1 shown in FIG. 3 is a cross-sectional view taken along line AA shown in FIG. 1, and FIG. 4 is a cross-sectional view taken along line BB shown in FIG. 1 (excluding the abutment 21). FIG. 5 is a cross-sectional view of the main beam 10 shown in FIGS. The right half of FIG. 2 is a view seen through the main girder 10 from the upper floor slab 23.

  A PC steel concrete composite girder bridge 1 shown in FIGS. 1 and 2 is a two-diameter continuous PC steel concrete composite girder bridge using a corrugated steel plate for the web. The main girder 10 of the PC steel concrete composite girder bridge 1 is provided with a steel flange 12 at the lower end of the corrugated steel web 11 and a concrete flange 13 integral with the upper end at the upper end of the corrugated steel web 11. An upper floor slab 23 is installed on the main girder 10. The main girder 10 and the upper floor slab 23 have a composite structure by a gibber bar 131 made of a reinforcing bar protruding from the upper surface 13 a of the concrete flange 13 of the main girder 10. The corrugated steel web 11 and the steel flange 12 are joined by welding. The PC steel concrete composite girder bridge 1 is a girder bridge in which a main girder 10 formed by connecting precast concrete bridge girder segments 101 is installed between an abutment 21 and a bridge pier 22.

  Further, a steel divator (deflecting part) 31 for guiding the outer cable 30 is provided in the vicinity of the intersection of the steel flange 12 and the corrugated steel web 11 at the end of the precast concrete bridge girder segment 101 in the main girder 10. Further, a fixing portion 32 for fixing the end portion of the outer cable 30 is provided on an end fulcrum cross beam 211 made of a concrete member located above the abutment 21. And, in the PC steel concrete composite girder bridge 1, the end portion is stretched between the two branches by the outer cable 30 spanned between the two diameters guided by the divator (deflecting portion) 31 and fixed to the fixing portion 32. Prestress in the direction of the girder axis is introduced.

  The PC steel concrete composite girder bridge 1 according to the present embodiment uses a corrugated steel plate for the web, so that it is strong against buckling and prestress in the girder axis direction is easily introduced. Moreover, in this embodiment, since the lower flange of the corrugated steel web 11 is made of steel, the weight of the girders can be reduced as compared with a conventional bridge girder whose upper and lower flanges are made of concrete. Further, according to the PC steel concrete composite girder bridge 1 of the present embodiment, the upper edge tension and the lower edge of the intermediate fulcrum portion are pulled by the prestress secondary force by the outer cable 30 stretched between the two diameters. Compressive stress is improved.

  Next, an embodiment of the construction method of the PC steel concrete composite girder bridge 1 of the present invention will be described.

  First, a corrugated steel web 11 having a steel flange 12 welded to the lower end is manufactured at a factory. The corrugated steel web 11 is transported to a precast concrete factory, and a concrete flange 13 is applied to the upper end of the corrugated steel web 11 to produce a precast concrete bridge girder segment 100.

  Hereinafter, with reference to FIGS. 6-10, the process of constructing the concrete flange 13 at the upper end of the corrugated steel sheet web 11 with the steel flange 12 welded to the lower end will be described.

  FIG. 6 is a side view showing the corrugated steel sheet web disposing step.

  6 shows the corrugated steel sheet webs 111 and 112 of the adjacent girders among the corrugated steel sheet webs 11 which are used in the PC steel concrete composite girder bridge 1 shown in FIGS. A portion in the vicinity of the joining end is shown. As shown in FIG. 6, the corrugated steel webs 111 and 112 adjacent to each other in the longitudinal direction of the girders are arranged to face each other with a gap 40 between the joining ends (corrugated steel web provision step). Holes 111a and 112a for attaching temporary attachment plates and permanent attachment plates, which will be described later, are provided in the vicinity of the joining end portions where the corrugated steel webs 111 and 112 are abutted.

  Next, the corrugated steel sheet web joining step shown in FIG. 7 is entered. FIG. 7 is a side view showing the corrugated steel sheet web coupling step.

  The temporary attachment plate 51 is fixed with bolts 61 in the holes 111a and 112a (see FIG. 6) provided in the corrugated steel webs 111 and 112 which are arranged to be abutted with a gap 40 in the corrugated steel web arranging process. Thus, as shown in FIG. 7, the corrugated steel webs 111 and 112 are joined together (corrugated steel web joining process).

  Next, the mold attachment process shown in FIG. 8 is entered. FIG. 8 is a side view showing the mold attachment process.

  As shown in FIG. 8, a flange mold 80 (80a, 80b) is formed around the upper ends 111b, 112b of the corrugated steel webs 111, 112 joined by the temporary splicing plate 51 with a gap 40 in the corrugated steel web joining process. ). At this time, the partition plate 70 thinner than the dimension of the gap 40 is sandwiched between the adjacent flange molds 80a and 80b (mold attachment process). When the partition plate 70 is sandwiched, the partition plate 70 is sandwiched so that the center in the thickness direction of the partition plate 70 coincides with the center of the gap 40. Further, the difference between the dimension of the gap 40 and the thickness dimension of the partition plate 70 is set to a value that is equal to or slightly larger than the shrinkage amount of the concrete flange 13 in the longitudinal direction of the concrete flange 13 (for example, in this embodiment, the gap 40 The dimension was 12 mm, and the thickness dimension of the partition plate 70 was 9 mm.) By doing so, when the longitudinal length of the concrete flange 13 of each precast concrete bridge girder segment 100 produced shrinks, it is avoided that the butt end of the corrugated steel sheet web that does not shrink protrudes from the concrete end face. And the corrugated steel webs 111 and 112 can be joined with high accuracy. Moreover, in this embodiment, since the corrugated steel sheet webs 111 and 112 and the concrete flange 13 are joined by the embedded joining method, the upper ends 111b and 112b of the corrugated steel sheet webs 111 and 112 are made of the concrete of the flange mold 80, respectively. It is arranged at the part to be placed.

  Next, the concrete placement process shown in FIG. 9 is entered. FIG. 9 is a side view showing the concrete placing step.

  As shown in FIG. 9, the concrete 13 is cast and cured on the flange mold 80 assembled in the mold mounting process, and the flange mold 80 is removed (concrete casting process). The upper ends 111 b and 112 b of the corrugated steel webs 111 and 112 are embedded in the concrete flange 13, and the corrugated steel webs 111 and 112 and the concrete flange 13 are joined. The concrete 13 is placed in a state where the partition plate 70 is sandwiched between adjacent flange molds 80a and 80b. Accordingly, the corrugated steel webs 111 and 112 are moved from the end surfaces of the adjacent concrete flanges 13 by a difference (for example, 3 mm) between the dimension of the gap 40 (for example, 12 mm) and the thickness dimension (for example, 9 mm) of the partition plate 70. Will also be disposed in a retracted state.

  Next, the segment separation process shown in FIG. 10 is entered. FIG. 10 is a side view showing the segment separation step.

  As shown in FIG. 10, the pre-cast concrete bridge girder segments 100 in which the flange formwork 80 is removed in the concrete placing process are moved horizontally as shown in FIG. To separate (segment separation step). Further, the partition plate 70 sandwiched between the adjacent concrete flanges 13 is also removed.

  The segment length and segment weight of the precast concrete bridge girder segment 100 manufactured through the steps described above with reference to FIGS. 6 to 10 are determined, for example, from the length of the trailer used for transportation, the maximum load capacity, and the like. Here, as an example, the segment length is about 6 m, and the segment weight is 30 t or less.

  FIG. 11 is a side view showing the segment connecting step.

  A precast concrete bridge girder segment 100 of about 6 m is transported to the site by a trailer, and an epoxy resin adhesive or an acrylic resin adhesive is applied to the end faces of the concrete flanges 13 of the two precast concrete bridge girder segments 100 to Pull the end faces together to join them. Further, as shown in FIG. 11, the corrugated steel webs 111 and 112 are joined to each other by fixing the splicing plate 52 with bolts 62 in the holes 111 a and 112 a provided in the corrugated steel webs 111 and 112. Further, the steel flanges 12 welded to the lower end of the corrugated steel sheet web 11 are joined together by fixing the attachment plate 53 with a bolt 63. In this way, the two precast concrete bridge girder segments 100 are grounded and connected to form a precast concrete bridge girder segment 101 of about 12 m.

  Even if the concrete is cured and contracted until the concrete flange 13 of the precast concrete bridge girder segment 100 manufactured through the steps described with reference to FIGS. 12 mm) and the difference in thickness (9 mm) between the partition plates (9 mm), the amount of shrinkage in the longitudinal direction of the concrete flange 13 is offset, and the joining ends of the corrugated steel webs 111 and 112 are the end faces of the concrete flange 13. Since it does not protrude more, the end surfaces of the concrete flange 13 of each precast concrete bridge girder segment 100 manufactured are easily and accurately joined.

  FIG. 12 is a side view showing the erection process of the precast concrete bridge girder segment 101 that has been laid.

  First, a large number of vents 90 are erected from the ground.

  Next, as shown in FIG. 12, the precast concrete bridge girder segment 101 that has been laid is erected in order so that the seam portion is placed on the vent 90 using a truck crane or the like, and 1 between the abutment 21 and the pier 22. Connect across the span. In addition, the precast concrete bridge girder segment 101 is also connected over one diameter between the other abutment 21 and the pier 22 (not shown in FIG. 12).

  After the ground precast concrete bridge girder segment 101 is erected and connected so that the seam portion is on the vent 90, the vent 90 is removed, and the girder has a structure that bears its own weight as a simple girder.

  This connection is performed by applying an epoxy resin-based adhesive or an acrylic resin-based adhesive to the end face of the concrete flange 13 of the precast concrete bridge girder segment 101 that has been laid in the same manner as the segment connecting step described with reference to FIG. Then, the end surfaces of the concrete flange 13 are pulled and joined. Further, the corrugated steel sheet webs are coupled to each other by fixing the splicing plate with bolts in holes provided in the corrugated steel sheet webs. Further, the steel flanges welded to the lower end of the corrugated steel sheet web are joined together by fixing the splicing plate with a bolt.

  Next, the upper floor slab 23 is applied to a portion other than the connection portion above the pier 22 and the weight of the main structure is placed on a simple girder.

  The floor slab may be a method of placing a precast floor slab on the main girder 10 or a method of placing a cast-in-place floor slab using a movable formwork or the like. Also good.

  Finally, the corrugated steel sheet webs in the connection part above the pier 22 are joined together by fixing the splicing plate with bolts, concrete is placed in the gap above the connection part above the pier 22, and the outer cable 30 is connected. The structural system is completed by stretching between the two spans and introducing prestress in the direction of the girder axis.

  It should be noted that the segment is transported and erected by normal girder erection in places where vent erection by a truck crane or the like cannot be performed.

  Bridge face work, bearing work, and fallen bridge prevention structure work are performed in the same way as conventional methods.

  In the erection method of the present embodiment, since a tensile force is generated on the steel flange 12 provided at the lower end of the corrugated steel web 11 by its own weight, a prestress is applied in the bridge axis direction by the outer cable 30, so that the steel flange 12 is buckled. Hateful.

  The joining of the concrete flange 13 at the upper end of the corrugated steel web 11 has a precast segment structure, but since it is always compressed, it is not disadvantageous in terms of structure.

  Since the upper flange of the corrugated steel sheet web 11 is concrete, it has good jointability with the upper floor slab concrete, and it is easy to have a composite structure with gibber bars by reinforcing bars.

  In the above-described embodiment, an example of a two-diameter continuous PC steel-concrete composite girder bridge has been given as an example of the PC steel-concrete composite girder bridge of the present invention. PC steel concrete composite girder bridges or PC steel concrete composite girder bridges of three or more spans may be used.

  Further, in the above-described embodiment, an example in which the prestress in the girder axis direction is introduced by extending the outer cable between the two spans, the present invention is not limited to this, for example, Introducing prestress in the direction of the girder axis by extending the outer cable between the spans of one diameter, or introducing prestress in the bridge girder using multiple external girder cables across multiple diameters. Alternatively, prestress may be introduced into the bridge girder using an outer cable that spans several spans among a plurality of spans.

It is a side view of the PC steel concrete composite girder bridge which is one embodiment of the present invention. It is a top view of the PC steel concrete composite girder bridge 1 shown in FIG. It is AA sectional drawing shown in FIG. It is BB sectional drawing shown in FIG. It is sectional drawing of the main girder 10 shown in FIG. 1, FIG. It is a side view which shows a corrugated steel plate arrangement | positioning process. It is a side view which shows a corrugated steel plate joint process. It is a side view which shows a mold attachment process. It is a side view which shows a concrete placement process. It is a side view which shows a segment separation process. It is a side view which shows a segment connection process. It is a side view which shows the construction process of the precast concrete bridge girder segment assembled.

Explanation of symbols

1 PC steel concrete composite girder bridge 10 Main girder 11, 111, 112 Corrugated steel web 111a, 112a Hole 111b, 112b Upper end 12 Steel flange 13 Concrete flange 13a Upper surface 131 Giber louver 100, 101 Precast concrete bridge girder segment 21 Abutment 211 End fulcrum Cross girder 22 Bridge pier 221 Intermediate fulcrum cross girder 23 Upper floor slab 30 Outer cable 31 Divider (deflection part)
32 Fixing portion 40 Clearance 51 Temporary attachment plate 52 Main attachment plate 53 Attachment plate 61, 62, 63 Bolt 70 Partition plate 80, 80a, 80b Flange mold 90 Vent

Claims (3)

  A PC steel concrete composite girder bridge having a steel flange at the lower end of the corrugated steel sheet web, a concrete flange integral with the upper end of the corrugated steel sheet web at the upper end, and an external cable stretched in the bridge axis direction of the bridge .   A precast concrete bridge girder segment is manufactured by forming a concrete flange integral with the corrugated steel sheet web at the upper end of a corrugated steel sheet web with a steel flange attached to the lower end, and the precast concrete bridge girder segment is sequentially placed between the piers by venting or girder erection. The concrete flange end face between each precast concrete bridge girder segment is abutted, the corrugated steel web is joined, the steel flange is joined in the direction of the bridge axis, and the bridge girder is supported between the piers as a simple girder. A construction method for PC steel concrete composite girder bridges, in which pre-stress is introduced into the bridge girders between the piers using external cables in the direction of the bridge axis of the bridge.   The PC steel concrete composite girder bridge according to claim 2, characterized in that a plurality of bridge girders are continuous between the spans, and prestress is introduced into the bridge girders by using an external cable arranged in the bridge axial direction across the plural spans. Construction method.

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