KR20030014686A - Method of constructing simple and continuous composite bridges - Google Patents

Abstract

PURPOSE: Provided is a method of constructing simple and continuous composite bridges, such as simple and continuous preflex composite bridges, prestressed concrete(PSC) composite bridges, steel box girder bridges, plate girder bridges, and long span truss bridges. CONSTITUTION: The method of constructing simple composite bridges comprises the steps of: providing first and second abutments; implanting a shape steel in a bridge seat portion of the first abutment; simply resting a beam on the first and second abutments; connecting the shape steel in the bridge seat portion to a lower flange of the beam; applying a connecting concrete to a portion ranging from an upper end of the first abutment to a neutral axis of the beam; lowering a support near the second abutment; applying a concrete to a portion ranging from an upper end of the connecting concrete to a bottom plate of the beam; applying a floor slab concrete to the beam; and lifting up the lowered support near the second abutment.

Description

METHOD OF CONSTRUCTING SIMPLE AND CONTINUOUS COMPOSITE BRIDGES}

In the prior art of the construction method of the short span and multi span composite girder bridges, in the case of the short span, a simple beam type preflex composite beam using the branch point of Korean Laid-Open Patent Publication No. 0250937 (hereinafter referred to as Cited Invention 1) In the case of multi-span, there is a continuous beam prestressed composite beam of Korea Patent Publication No. 105754 (hereinafter referred to as Invention 2) and a method of constructing a prestress continuous composite beam structure using the same.

1A to 1D show the process of constructing the composite bridge of Citation Invention 1. Referring to these drawings, Cited Invention 1 will be described below.

1A and 1B, first, a branch 51 is installed at the center of a bridge by mounting a preflex beam manufactured at a factory or a site between shifts, and creep of initial concrete. In order to recover the compressive stress loss due to creep and dry shrinkage, the branch point 51 is raised to further introduce the compressive stress to the lower casing concrete 52.

Next, as shown in FIG. 1C, the upper baseplate concrete 53 and the abdominal concrete are poured and cured while the branch 51 is raised. Lastly, as shown in FIG. 1D, after the upper bottom plate concrete 53 is cured, the branch 51 is removed to complete the simple beam preplex composite bridge.

However, Cited Invention 1 manufactured by the above-described method should be provided with an upward load by installing a branch point in the center of the beam, and in particular, due to the installation of a stirrup in a place where the mold space is high. In addition to expensive additional costs, this impedes the flow of traffic under the bridge and complicates construction.

In addition, Cited Invention 1, because the entire bridge behaves as a simple beam system, structurally, due to the maximum positive moment generated in the center of the beam, the cross section of the composite mold must be large, The additional use problem of excessive deflection at the center of the beam is also a disadvantage.

2A to 2E and 3A to 3G show a process of manufacturing a two-span continuous composite bridge and a three-span continuous composite bridge according to Citation Invention 2, respectively.

First, the construction method of the two-span continuous composite girder bridge will be described, as shown in Figure 2a, the preflex beams made for each span according to the design of the continuous beams are connected and mounted at the second point (54). Next, as shown in FIG. 2B, the connected second point 54 is raised to further introduce a compressive stress to the lower casing concrete 52. Next, as shown in FIG. 2C, the bottom plate concrete 53 surrounding the upper flange of the steel girder near the second point 54 is poured and cured, and as shown in FIG. 2D. The point is lowered to introduce a compressive stress corresponding to the negative moment occurring in the bottom plate concrete near the second point 54. Next, as shown in FIG. 2E, when the bottom plate concrete of the remaining sections is poured, a complete two-span continuous preplex composite bridge is completed.

3a to 3h illustrate the construction process of the three-span continuous preplex composite bridge. In the three-span continuous composite bridge, the construction process at the second point 54 is the same as the construction process of the two-span continuous preplex composite bridge shown in FIG. 2. Done. Next, as shown in FIGS. 3E-3H, the third point 55 is raised, the bottom plate concrete 53 is poured, the third point 53 is lowered, and the remaining bottom plate concrete is poured. This completes a three span continuous preplex composite bridge.

However, Cited Invention 2 manufactured as described above may cause the occurrence of construction joints due to the time difference between the bottom plate concrete placing in the section of the constant moment and the parent moment. The work is inconvenient and involves the risk of a safety accident because the work must be done on the bridge, that is, on the second and third points, not on adjacent bridges.

In addition, in both Cited Invention 1 and Cited Invention 2, a bridge arrangement, which acts as a medium for transferring the load of the superstructure to the lower structure, has a hinge point that allows rotation only, and can rotate and move. It is composed of roller points, which not only have to pay attention to the continuous maintenance of the superstructure, but also can be fatally damaged in case of earthquake.

The invention only span (單徑間) and the span Preflex (preflex) composite girder bridge, PSC composite girder bridges, steel box girder bridges (steel box girder bridge), steel girder bridge (plate girder bridge), Chapter span (long span) Truss It relates to the construction method of short span and multi span composite girder bridges, such as bridges.

Figure 1 shows the construction process of a short span preplex composite bridge according to the prior art.

Figure 2 shows the construction process of a two-span continuous preplex composite bridge according to the prior art.

Figure 3 shows the construction process of the three-span continuous preplex composite bridge according to the prior art.

4 is a diagram illustrating a connection state between a shift and a composite type for construction of a short-span preflex composite bridge according to the present invention.

Figure 5 is a connection state of the alternating and composite type for the construction of short span steel box girder bridge according to the present invention.

6 is a diagram illustrating a connection state between a shift and a composite type for construction of a short span PSC composite bridge according to the present invention.

Figure 7 shows the construction process of the short span composite bridge in accordance with the present invention.

Figure 8 shows the construction process of a two-span continuous composite girder bridge is not integrated with the composite type and the piers according to the present invention.

Figure 9 shows the construction process of a three-span continuous composite bridge without the composite type and bridge piers according to the present invention.

10 is a diagram illustrating a connection state of beams and beams at internal points during construction of a multi-span continuous composite bridge according to the present invention.

FIG. 11 is a diagram illustrating a connection state between a pier and a composite die for the construction of a multi-span continuous preplex composite girder bridge in which the composite die and the pier are integrated according to the present invention. FIG.

12 is a diagram illustrating a connection state between a pier and a composite die for construction of a multi-span continuous steel box girder bridge in which a composite die and a pier are integrated according to the present invention.

FIG. 13 is a diagram illustrating a connection state between a pier and a composite bridge for the construction of a multi-span continuous PSC composite bridge in which the composite bridge and the bridge are integrated according to the present invention. FIG.

Figure 14 shows the construction process of a two-span continuous composite girder bridge in which the composite type and pier integrated according to the present invention.

Figure 15 shows the construction process of the three-span continuous composite bridges in which the composite type and piers integrated according to the present invention.

Description of the main parts of the drawing

1: Church head 2: Beam 3: section steel

4: connecting plate 5: bolt 6: rebar

8: Reinforcement 9: Stud 10: Connecting concrete

11: joint concrete 12: connecting jaw 13: pier

14: shaped steel 15: welding 60: lower flange

61: bottom plate 62: plate 63: chest wall

64: tensile rebar

The present invention is to solve the above conventional problems, the object is to completely integrate the beam and the alternating only one point in the construction of the short-span composite bridge, and in the case of the multi-span composite bridge Practical and practical, further introducing compressive stress into the upper deck concrete of the parent section and the lower flange of the composite type through the process of lowering and raising the points on the alternating, ie end points, with or without integration. It is possible and economical to provide new construction methods for short span and multi span composite bridges.

The construction method of the short span composite girder bridge according to the present invention for realizing this includes the steps of: preparing a first shift and a second shift; Burying a section steel in the first alternating seat; Simply mounting a beam between the first and second shifts; Connecting the first alternating section steel and the lower flange of the beam; Placing connecting concrete from an upper end of the alternating portion of the first shift to a neutral axis of the beam; Lowering the point on the second shift side; Placing concrete from an upper end of the first alternating connecting concrete to the bottom plate of the beam; Placing concrete slabs over the entire section of the beam; And raising the point of the second shift side down.

In addition, the construction method of a multi-span continuous composite girder bridge according to the present invention comprises the steps of connecting at least two or more beams to each other by simply mounting between the first and second shifts, and at least one inner pier; Lowering the point on the first and second alternating sides; Placing slab concrete over the entire section of the beams; And raising the points on the first and second alternating sides that are lowered.

In the construction of the preplex composite type, the method further includes the step of placing the lower casing concrete at the connection of the beams before the simple mounting of the beams.

Preferably, the construction method of the multi-span continuous composite girder bridge further includes, before the step of simply mounting the beams, burying the steel in the coping of the inner pier, and simply placing the beams. Connecting the lower flange of the beam and the beam; Placing the connecting concrete from the upper end of the coping portion of the inner pier to the neutral axis of the beams; and lowering the points of the first and second alternating sides, and then the upper end of the connecting concrete of the inner pier. And pouring concrete from to the bottom plate of the beams.

Here, when the point of the first and second shift side is lowered, the point of the first shift side and the point of the second shift side are lowered simultaneously, and when the point of the first and second shift side is lowered. The point on the first shift side and the point on the second shift side are simultaneously raised.

As another alternative, however, when the point on the first and second shift side descends, the point on the first shift side and the point on the second shift side are sequentially lowered, and the point on the first and second shift side. At the time of rising, the point on the first shift side and the point on the second shift side may be raised in sequence.

In the case of the two-span continuous composite girder bridge, when the point on the first and second shift side descends, only one point of the first shift side and the second shift side is lowered, and the first and second shift side When rising of the point of only to raise the one point lowered.

On the other hand, in the construction method for the construction of the preflex composite girder bridge, if the beam and the piers are not integrated, the step of placing a simple casing concrete on the piers after the connection of the beam is further included.

Here, in the construction of a two-span continuous composite girder bridge, only one of the first alternating side and the second alternating side is lowered when the points on the first and second alternating sides are lowered, and the first and second Only the one point lowered when the point on the alternate side rises is raised.

On the other hand, the construction method for the construction of preplex composite girder bridge or steel box girder bridge further includes the step of providing a plurality of reinforcement and studs on the abdomen of the beam.

In addition, the construction method for the construction of the PSC composite girder bridge further includes the step of pulling the reinforcing bar in the abdomen of the beam

In addition, in constructing a PSC composite bridge, prior to the step of lowering the point of the second shift side, the step of placing the bottom plate concrete in the constant moment section of the chest wall and the beam of the first shift, and the chest wall and the floor It is preferable to further include the step of embedding connecting reinforcing bar connecting the concrete.

In addition, in constructing a PSC composite bridge, before the step of lowering the points of the first and second alternating side, the step of placing the bottom plate concrete in the constant moment section of the beams, and the bottom plate concrete connected to each other It is preferable to further include the step of embedding the connecting bar.

Here, the connection position of the beams may be placed at the inner point, or may be placed at any one of the left and right of the inner point.

Hereinafter, with reference to the accompanying drawings will be described the construction method of the short span and multi-span composite bridge according to the present invention. The construction method according to the present invention can be applied to both preplex composite bridges, PSC composite bridges, steel box bridges, steel plate bridges, long span truss bridges.

4 to 7 relates to a construction method of integrating beams and alternations in a short span composite girder bridge, and FIG. 4 shows a simple mounting of a preflex beam 2 made of a simple beam between a pair of alternations. In the state, it connects between the alternating part 1 and the preflex beam 2 in the state. First, as shown in FIG. 4A, the H-shaped or □ steel 3 is buried in the abutment portion 1, and the connecting plate 4 for connection with the lower flange 60 of the beam 2 is placed thereon. After welding, the shaped steel 3 is connected to the lower flange of the beam 2 by bolts 5 or by welding. In addition, the reinforcing material (8) is installed in the beam (2) to reinforce, and the steel (girder) to be covered with concrete ( studs 9) can be installed to enhance the composite effect with the concrete.

Next, as shown in FIG. 4B, the connecting concrete 10 is poured into and integrated from the top of the shift to the neutral axis of the cross section of the preflex beam 2 and connected to secure the integrity with the concrete to be poured next. The rebars (6) are pre-drawn out on the concrete (10) again.

Next, as shown in Figure 4c, by placing the concrete together with the upper base plate 61 to serve as a complete fixing point.

4D shows a plan view of the shifts according to this process.

FIG. 5 shows a case of a steel box-shaped bridge, in which the steel box-shaped 2 is connected between the alternating portion 1 and the steel box-shaped 2 on one side in a state where the steel box 2 is simply mounted between the shifts.

As in the case of FIG. 4, as shown in FIG. 5A, first, the H-shaped or □ steel 3 is buried in the abutment portion 1, and the connection with the lower flange 60 of the steel box 2 is placed thereon. After welding the connecting plate 4 for the connection, the shaped steel 3 is connected to the lower flange 60 of the steel box 2 by bolts 5 or by welding. In addition, by installing the reinforcing material (8) to the steel box type (2) to reinforce, and to install the studs (9) in the steel to be covered with concrete can improve the composite effect with the concrete.

Next, as shown in FIG. 5B, the connecting concrete 10 is poured from the upper end of the shift to the neutral axis of the cross section of the steel box type 2 to be integrated, and then the connecting concrete ( 10) Pull out the rebars (6) in advance again.

Next, as shown in Figure 5c, by placing the concrete with the upper bottom plate 61 to serve as a complete fixing point.

FIG. 6 shows a case where the PSC beam 2 is connected between the alternating portion 1 of one shift and the PSC beam 2 while the PSC beam 2 is simply mounted between the shifts.

As in the case of FIGS. 4 and 5, as shown in FIG. 6A, first, the H-shaped or □ steel 3 is buried in the abutment portion 1, and the connection with the lower flange of the PSC beam 2 is placed thereon. After welding the connecting plate 4 for the purpose, the section steel 3 is connected by welding 15 with the plate 62 embedded in the concrete of the lower flange of the PSC beam 2.

Next, as shown in FIG. 6B, the concrete is connected from the fixed point side to the neutral axis of the cross section of the PSC beam 2 at the same time as the bottom plate concrete placing in the remaining sections except for approximately 10% of the entire span length. (10) is poured and integrated, and alternate chest walls 63 are also provided. In addition, the reinforcing bars 6 are pulled out in advance on the connecting concrete 10 and on the chest wall to secure the integrity with the concrete to be poured next. Here, the alternating chest wall (63) and the bottom plate concrete is placed in advance to bury the tension reinforcement (64) to cope with the tensile force generated during the lowering of the moving point during the construction process. The length of the section is about 10%, which is the value determined by the parameter study of the length of the parent section in the case of bridges with a length of 30m, which is the most efficient to introduce the compressive stress. Depending on the type and material of concrete used.

Next, as shown in Figure 6c, by placing the concrete together with the remaining upper base plate 61 to serve as a complete fixing point.

Figure 7 shows the construction process of the short span composite bridge.

FIG. 7a shows a state diagram in which a beam manufactured at a factory or a site is simply mounted on a pair of shifts, and then one point is fixed to the fixed point 71 and the other point is moved to the moving point 72.

7b shows the process of introducing the compressive stress to the lower flange of the beam by lowering the point of movement 72 and the resulting moment diagram.

FIG. 7C illustrates a state diagram in which the bottom plate concrete (reference numeral 61 in FIGS. 4C, 5C, and 6C) is poured in a state where the moving point 72 is lowered, and a moment diagram thereof.

Figure 7d shows that after the bottom plate concrete is cured, the lowered moving point 72 is raised to introduce a compressive stress corresponding to the parent moment generated at the fixed point 71 side to the bottom plate concrete. By the process of Fig. 7d, tensile stress is generated in the lower flange, which corresponds to about 60-70% of the compressive stress introduced upon the lowering of the moving point 72 due to the increased cross-sectional stiffness after synthesis. The compressive prestressing effect is about 30-40%.

Here, in the case of PSC composite girder bridge, the bottom plate concrete is poured in the section except about 10% of the section length from the fixed point end before the moving point is lowered, and the rest section is poured after the end point is lowered.

In the case of the short span composite girder bridge of the present invention, due to the large moment of the fixed point portion, about 10% of the length of the span length from the fixed point end is increased in cross section, and thus the design can be made into a variable cross section.

8 and 9 illustrate a construction method for excluding the possibility of occurrence of construction joints, which is a problem of Citation Invention 2 described in the related art, and the risk of a safety accident caused by performing a point raising and lowering operation on a pier. It can be applied to preplex composite bridge, PSC composite bridge, steel box bridge, steel plate bridge, long span truss bridge, etc.

8 is a view illustrating a construction process of a two-span continuous composite bridge in which a bridge and a composite die are not integrated according to the present invention, wherein the second invention in which the cited invention 2 is an internal point is raised to further compress the lower flange of the constant moment section. Unlike the introduction of stress, as shown in FIG. 8A, the present invention mounts a preflex beam or PSC beam made of a simple beam on alternating and piers and connects at an internal point 73 as shown in FIGS. 10A and 10C. Alternatively, as shown in FIG. 10B, one of the left or right sides of the inner point 73 is connected in the parent section of the entire bridge.

Figure 8b shows a state diagram and the resulting moment diagram to introduce additional compressive stress to the lower flange by lowering the points at both ends on the alternating side.

Figure 8c shows a state diagram and the moment diagram resulting from placing the bottom plate concrete in the state of lowering the points of both ends.

FIG. 8D shows that after the bottom plate concrete is cured, the compressive stress corresponding to the tensile stress occurring at the inner point portion after synthesis is introduced by raising the points at both ends lowered to the bottom plate concrete. By the process of Fig. 8d, as in the case of short span, tensile stress is generated in the lower flange, which corresponds to about 60-70% of the compressive stress introduced at the lowering of both ends due to the increased stiffness after synthesis. As a result, a compression prestressing effect of about 30-40% is obtained.

Likewise, in the case of PSC composite girder bridges, the bottom plate concrete is placed in the section except about 10% of the length of the inter-section to the left and right of the inner point before descending the points at both ends. Pour.

Figure 9 shows the construction process of the three-span continuous composite bridges are not integrated with the bridge and composite type according to the present invention.

FIG. 9A shows the fabricated preflex beam or PSC beam mounted on the alternating and pier, and at one of the right or left sides of the piers in the parent section of the entire bridge at or away from the inner point; FIGS. 10A, 10B, and 10C. It is a state diagram connected together.

As described above, as shown in FIG. 9B, the second point 73 and the third point 74, which are cited by Invention 2, are sequentially raised to introduce additional compressive stress to the lower flange of the constant moment section. Contrary to this, the present invention achieves the same effect by lowering the points at both ends alternately or sequentially.

9C shows a state diagram in which the bottom plate concrete is poured in a state where the points at both ends are lowered, and a moment diagram thereof.

FIG. 9D shows that after the bottom plate concrete is cured, both end points which have been lowered are raised to introduce compressive stresses corresponding to the tensile stresses generated at the internal points after the synthesis into the bottom plate concrete. Here too, tensile stress occurs in the lower flange, which corresponds to about 60-70% of the compressive stress introduced at the drop of both ends due to the increased stiffness after synthesis, resulting in about 30-40%. You will get some compression prestressing effect. In the case of three-span continuous composite girder bridge where the pier and composite die of the present invention are not integrated, the static moment generated in the inner span is about 1/5 of the absolute value generated in the inner point part due to the structural characteristics of the continuous beam. As a result, sufficient compressive stress is retained even when no additional compression prestressing is introduced at the lowering and raising of both ends.

Likewise, in the case of PSC composite girder bridges, the bottom plate concrete is placed in the section except about 10% of the length of the inter-section to the left and right of the inner point before descending the points at both ends. Pour.

FIG. 10A shows a detailed view in which two beams 2 are connected by a plurality of connecting plates 4 and bolts 5 at internal points in the case of a preflex composite bridge. In the case of Cited Invention 2 described in the related art, after raising the point, the bottom plate concrete of the parent section is poured, and at the same time, the joint concrete 11 is placed on the inner point, whereas in the present invention, both ends Before lowering the point of the end, the joint concrete 11 is poured into the internal point.

FIG. 10B shows another connection method in the case of the above-described preflex composite girder bridge, in which two beams 2 are connected to a plurality of connection plates 4 and bolts 5 at one of the right side or the left side of the pier outside the inner point. The detailed diagram connected by these is shown. Similarly, in the case of Cited Invention 2 described in the related art, after elevating the point, the bottom plate concrete of the parent section is poured and the joint concrete 11 is placed in the internal point, whereas in the case of the present invention, Before lowering the points at both ends, the joint concrete 11 of the connection is poured.

FIG. 10C shows a detailed view of connecting two beams 2 at internal points in the case of a PSC composite bridge. In the production of each PSC beam, bolts 5 are inserted in the concrete of the upper flange in advance, and continuity is achieved by using the connecting plate 4 in connection of the beams. The beam is also connected to the lower flange using connecting bars 6. This is because the lower flange of the inner point is the compression side, so that the role of the connecting reinforcement 6 is not large, but is intended to stabilize the entire composite type. In addition, the connecting jaw 12 is installed on the neutral shaft of the beam for convenience in connection work, and filling the gap with no shrinkage mortar.

Since the steel box girder bridge does not have a connection at the inner point, the method of the present invention can be applied more easily.

11 to 15 is another example of the construction method of the multi-span continuous composite girder bridge, to further prepare for the problems of the bridge device and damage during the earthquake by integrating the beam and the pier. The integration method and construction method are described as follows.

In the case of the preflex composite bridge, as shown in FIG. 11A, two preflex beams 2 made of simple beams are formed with a plurality of connecting plates 4 and bolts 5, as in FIG. 10A. After connecting to the bridge (13), which was buried in the bridge 13 in advance, and connected by welding to the lower flange 60 of the steel. In addition, the reinforcing bars 6 are pulled out in advance from the lower casing concrete 52 of the piers 13 and the beams 2 in order to assist the integration with the connecting concrete 10 to be poured in the next step. Then, as shown in Figure 11b, the concrete of the remaining lower flange of the beam (2) and the connecting concrete (10) is poured and integrated from the top of the bridge 13 to the neutral axis of the cross section of the beam, the concrete to be poured next The bars (6) are pulled out again for the purpose of unity with.

As shown in Fig. 11C, in the state where the end point of the multi-span continuous composite bridge of the present invention is lowered, the beam 2 and the pier 13 are formed by pouring the remaining upper end of the pier at the same time as placing the bottom plate concrete and the abdominal concrete. This fully integrated multi-span continuous preplex composite bridge can be completed. FIG. 11D is a plan view of the □ steel 14 buried in the piers 13. FIG.

12 shows the case of a steel box bridge.

As shown in Fig. 12A, after placing the steel box shape 2, which is a segment corresponding to the parent section, on the □ steel 14 previously buried in the piers 13, the lower flange of the beam 2 60 is connected by welding. As shown in FIG. 12B, the connecting concrete 10 is poured into and integrated from the upper end of the bridge 13 to the neutral axis of the cross section of the beam 2. Here, the reinforcement (6) is pulled out from the pier (13), the reinforcement is installed by the reinforcement (8) to the steel box-shaped abdomen, and the upper flange as well as the abdomen studs (9) by installing a composite effect with concrete Uplift. In particular, in the case of a steel box bridge, since there is no joint of the composite type on the piers, the method of the present invention can be applied more easily.

As shown in Fig. 12C, in the state where the end point of the multi-span continuous composite bridge of the present invention is lowered, the multi-span continuous steel box in which the beam and the piers are completely integrated by pouring the remaining upper end of the piers simultaneously with the pouring of the bottom plate concrete. Can complete the bridge.

Fig. 13 shows the case of PSC composite bridge.

As shown in FIG. 13A, two PSC beams 2 interconnected as shown in FIG. 10B are similarly placed on the □ steel 14 previously buried in the piers 13, and then connected in the concrete of the lower flange. The plate 4 is connected by welding. Next, as shown in Fig. 13b, from the inner point to the left and right sections except for about 10% of the length of the corresponding section, the bottom plate concrete placing and connecting from the upper end of the piers to the neutral axis of the cross section of the PSC beam 2 The concrete 10 is poured and integrated. In addition, the reinforcing bars 6 are previously pulled back into the connecting concrete 10 to secure the integrity with the concrete to be poured next time. Here, the bottom plate concrete placed in the remaining sections except the inner point portion is connected to the buried reinforcement bar 64 in advance. This is to cope with the tensile force generated during the lowering of both end points during the construction process. About 10% of the section length is the value determined by parameter study of the length of the parent section section in the case of bridges with a length of 30m, which is the most efficient to introduce the compressive stress. Depending on the type and material of concrete used.

As shown in FIG. 13C, at the same time as the other end of the present invention in the lowered state of the rest of the bottom plate concrete, and by pouring the remaining top of the pier to complete the multi-span continuous PSC composite bridge with the beam and pier fully integrated Can be.

Figure 14 shows the construction process of a two-span continuous composite girder bridge to integrate the bridge and composite die.

FIG. 14A illustrates a process of introducing additional compressive stress to the lower flange by simultaneously or sequentially lowering both end points of the entire structure after connecting the composite die and the piers as shown in FIGS. 11B, 12B, and 13B; The resulting moment diagram is shown.

14B shows a process of pouring the bottom plate concrete in a state where both ends are lowered, and a moment diagram thereof. Here, as shown in FIGS. 11C, 12C, and 13C, at the same time as placing the bottom plate concrete, the concrete is poured into the remaining upper end portion of the piers to completely integrate the piers and the composite die.

14C shows the compressive stress corresponding to the tensile stress generated in the bottom plate concrete of the parent section during the design activation by raising or lowering both end points simultaneously or sequentially after the bottom plate concrete and the top concrete of the piers are cured. It is shown to introduce. In this construction step, tensile stress is generated in the lower flange of the constant moment section, which corresponds to about 60-70% of the compressive stress introduced at both ends due to the increased stiffness after synthesis, resulting in about 30 -40% compression prestressing effect.

In the case of PSC composite girder bridges, the bottom plate concrete is cast in the section except about 10% of the length of the section to the left and right of the inner point before descending the points at both ends.

In the case of the two-span continuous composite bridge shown in FIGS. 8 and 14, the same effect can be obtained even by lowering and raising only one end point according to the site conditions. In this case, however, two batches are to be applied in the amount of descending and the amount of lifting as compared with the case of lowering and raising both ends simultaneously or sequentially.

15 is a view illustrating a construction process of a three-span continuous composite bridge in which a bridge and a composite bridge according to the present invention are integrated.

FIG. 15A illustrates a process of introducing additional compressive stress into the lower flange by simultaneously or sequentially lowering both end points of the entire structure after connecting the composite die and the piers as shown in FIGS. 11B, 12B and 13B. The resulting moment is shown.

15B illustrates a process of pouring the bottom plate concrete in a state where both end points are lowered, and a moment diagram thereof. Here, as shown in FIGS. 11C, 12C, and 13C, at the same time as the bottom plate concrete is poured, the remaining upper end of the bridge is also cast concrete to completely integrate the bridge and the composite type.

15c shows the compressive stress corresponding to the tensile stress generated in the bottom plate concrete of the parent section section by the design live load by raising or lowering both end points simultaneously or sequentially after the bottom plate concrete and the top concrete of the piers are cured. It is shown to introduce. As with the two-span continuous composite bridges, tensile stresses are generated in the lower flanges at this stage of construction, corresponding to about 60-70% of the compressive stress introduced at the end point drop due to the increased stiffness after synthesis. The result is a compression prestressing effect of about 30-40%.

Likewise, in the case of PSC composite bridges, the bottom plate concrete is placed in the section except about 10% of the length of the intersection before the lower points of both ends, and the remaining sections after the lowering of both ends. Pour.

In the case of the three-span continuous composite bridge in which the bridge and the composite die are integrated according to the present invention, since the static moment generated in the inner span is only about 1 / 3.5 as an absolute value compared to the maximum parent generated in the inner point portion, both ends As the point descends and rises, there is sufficient compressive stress without the need for additional compression prestressing.

In addition, the multi-span continuous composite bridges in which the bridges and the composite dies are integrated according to the present invention have about 10% of the length between the bridges left and right from the bridges due to the large moment occurring near the integrated bridges and the composite dies. It is possible to design a variable cross section by increasing.

In addition, the short span and multi span composite structures according to the present invention can adjust the amount of compression prestress introduced into the lower flange of the composite by making the amount less than the falling amount of the end point.

In the case of the multi-span continuous composite bridges without integrating the upper composite type and the pier according to the present invention, the problems of the invention disclosed in the prior art described in the prior art by placing the bottom plate concrete at the same time and performing the point lowering and raising work in the adjacent positions on the land. The occurrence of construction joints due to the time difference between the concrete slabs in the acclimation / floor moments can be prevented, and the risk of inconvenience and safety accidents due to the lifting and lowering points in the piers can be ended.

In addition, the construction method of the short span composite bridge to integrate the upper composite type according to the present invention with one shift, and the multi span continuous composite bridge integrated with the bridge, in addition to the above-mentioned effects, the short span, two span and three span structures of the cited invention Whereas each is a determinated, primary and secondary indeterminated structure, the present invention converts into primary, fifth and eighth amorphous structures, respectively, As the energy dissipation effect due to plasticity is large, vibration reduction effect and seismic resistance can be greatly improved, and the large moment that can be generated by integrating the composite type and the substructure is distributed to the substructure, so the burden on the external force of the beam As a result of this reduction, about 20% reduction and extension effect can be expected in terms of shape and span, resulting in a more economical cross section.

In addition, it is possible to reduce the number of bridge devices that cause deterioration of all bridges and require constant maintenance, thereby increasing additional economics.

Claims (13)

Preparing a first shift and a second shift; Burying a section steel in the alternating portion of the first shift; Simply mounting a beam between the first and second shifts; Connecting the first alternating section steel and the lower flange of the beam; Placing connecting concrete from an upper end of the alternating portion of the first shift to a neutral axis of the beam; Lowering the point on the second shift side; Placing concrete from an upper end of the first alternating connecting concrete to the bottom plate of the beam; Pouring bottom plate concrete into the beam; And Raising the point of the second alternating side is lowered; Construction method of a short span composite girder bridge comprising a. Connecting at least two beams to each other to simply mount between the first and second shifts and at least one inner pier; Lowering the point on the first and second alternating sides; Placing slab concrete on the beams; And Raising the points of the first and second alternating side is lowered; Construction method of a multi-span continuous composite bridge comprising the. The method of claim 2, The construction method of the multi-span continuous composite bridge, characterized in that further comprising the step of pouring the bottom casing concrete to the connection of the beams before the simple mounting of the beams for the construction of the preflex composite type. The method of claim 2, Burying a section steel in a coping portion of the inner piers prior to simply mounting the beams; Following the simple mounting of the beams, connecting the beam and the lower flange of the beams; Placing connection concrete from an upper end of the coping portion of the inner pier to the neutral axis of the beams; And Following the step of lowering the points on the first and second alternating sides, pouring concrete from the top of the connecting concrete of the inner piers to the bottom plate of the beams; multi-span continuous Construction method of composite bridge. The method according to claim 2 or 4, At the time of descending the points on the first and second shift side, the point on the first shift side and the point on the second shift side are simultaneously lowered, The method of constructing a multi-span continuous composite bridge according to claim 1, wherein when the points on the first and second alternating sides are raised, the points on the first alternating side and the points on the second alternating side are simultaneously raised. The method according to claim 2 or 4, When the points of the first and second shift side descends, the points of the first shift side and the points of the second shift side are sequentially lowered, The construction method of the multi-span continuous composite beam bridge, characterized in that when the point of the first and second alternating side is raised, the point of the first alternating side and the point of the second alternating side are sequentially raised. The method according to claim 2 or 4, For the construction of a two-span continuous composite bridge, when descending the points on the first and second alternating sides, only one of the first alternating side and the second alternating side is lowered, The construction method of the multi-span continuous composite bridge as described above, wherein only one point lowered when the point on the first and second alternating sides is raised is raised. The method according to claim 1 or 4, And installing at least one reinforcement and a stud in the abdomen of the beams to construct the preplex composite bridge or steel box composite bridge. The method according to claim 1 or 4, The method of constructing a composite bridge further comprising the step of pulling out the reinforcing bars in the abdomen of the beams for the construction of a PSC composite bridge. The method of claim 1, In order to construct a PSC composite bridge, prior to the step of lowering the point of the second shift, the step of placing the bottom plate concrete in the moment of the moment of the chest wall and beam of the first shift; And embedding connecting reinforcing bar connecting the chest wall and the bottom plate concrete. The method according to claim 2 or 4, In order to construct a PSC composite girder bridge, prior to the step of lowering the points on the first and second alternating side, the step of placing the bottom plate concrete in the constant moment section of the beams; Embedding connecting reinforcing bars connecting the bottom plate concrete to each other. The method of claim 2, The construction method of the multi-span composite beam bridge, characterized in that the connection position of the beams to be placed at the inner point. The method of claim 2, The connection position of the beam is a construction method of a multi-span composite beam bridge characterized in that it is placed in any one of the left and right of the inner point.