JP2006009339A - Construction method for building continuous composite girder bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that cracking cannot be prevented due to the absence of the effective action of the application of a compressive force, because such a high compressive force as to deform not only concrete but also a steel girder is required and the concrete is shrunk by drying and shrinkage even after the compressive force is applied, in a conventional construction method wherein the forced compressive force is applied to the concrete integrally connected to the steel girder, in an early time after the construction of a concrete floor slab, so as to cancel out a tensile force occurring on an intermediate supporting point section, in the building of a continuous composite girder bridge. <P>SOLUTION: The concrete floor slab 9 is constructed in an unconnected state on the steel girder 4 which is laid across the intermediate supporting section 3; after that, building work is performed in other sections; and after the concrete floor slab is sufficiently dried and shrunk, the forced compressive force is applied to the concrete floor slab. Thus, the compressive force is applied to the concrete floor slab alone; the amount of shrinkage caused by the drying and shrinkage, occurring after the application of the compressive force, is reduced; and the compressive force is effectively applied so that the cracking can be prevented in an appropriate manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is to improve the concrete floor slab on the intermediate fulcrum where the tensile force in the direction of the bridge axis is applied in advance so that a forced compressive force is efficiently applied in advance, so that cracks occur in the concrete slab. The present invention relates to a construction method of a continuous composite girder that can be prevented.

  The continuous composite girder bridge that integrates the concrete slab and the steel girder includes the continuous composite girder bridge that does not give the concrete floor slab the compulsory compressive force in advance and the continuous composite girder bridge that gives the compulsory compressive force to the concrete slab in advance. Synthetic girder bridges are known.

  The former type of continuous composite girder bridge that does not prestress concrete floor slab in advance is to control the crack width to below the limit while allowing the concrete floor slab to crack. Therefore, the girder action that supports the load in the section where cracks occur in the concrete slab is expected only for steel girders and reinforcing bars.

  Moreover, the latter continuous composite girder bridge of the type in which a forced compressive force is applied to the concrete slab in advance prevents, for example, cracks from occurring in the concrete slab A of the intermediate fulcrum B as shown in FIG. Therefore, the compressive force is forcibly applied to the concrete slab A at the time of construction, but the figure is also omitted in the form of applying this compressive force, but the fulcrum part is provided at the initial stage after the concrete slab construction. PC steel that is inserted along the bridge axis direction into the concrete floor slab A of the fulcrum B as shown in FIG. It is known that a tension force is applied to D and this tension force is transmitted as a compression force P from the fixing portions at both ends to the concrete floor slab A.

On the other hand, among the above methods, for the composite girders that tension the PC steel D inserted through the concrete floor slab A to generate a compressive force on the concrete floor slab A, the contact surface between the steel girder and the concrete has a long curing time. By interfering with the delayed-curing resin, the steel girder does not restrain the concrete until a predetermined time elapses after the concrete is placed, and the concrete is forced to compress. Synthetic girders are known in which the influence of concrete deformation restraint by steel girders is made as small as possible for deformation and the like so that forced compression force is effectively applied.
Japanese Patent Laid-Open No. 2002-4475 JP 2003-278385 A

  Generally, in continuous composite girder bridges, there are sections where tensile force is generated in concrete slabs due to bridge surface loads such as pavements and railings, drying shrinkage and creep phenomenon of concrete slabs, or passing vehicles. If a tensile force higher than the tensile strength is applied to concrete that is weak to the strength, the concrete slab will crack.

  Among the continuous composite girders mentioned above, in the case of continuous composite girder bridges that do not prestress the concrete slab in advance, cracked concrete slabs do not contribute effectively to the girder action that supports the load. Therefore, steel girders and rebars must have a girder height that can withstand all loads and reduce the tensile deformation of the concrete floor slab, and control the crack width to a limit value that does not affect durability. Therefore, there is a problem that a dimension having a large girder rigidity is required, and the amount of steel material to be used increases, so that the economic effect is thin.

  On the other hand, as shown in FIG. 12, in the case of a continuous composite girder bridge in which a forced compressive force is preliminarily applied to the concrete floor slab, after the concrete floor slab A is constructed in order to avoid redundancy in the construction period on site. In general, a forced compressive force is applied at the initial stage. However, if a forced compression force is applied immediately after the construction of the concrete floor slab A, shrinkage due to creep phenomenon and drying shrinkage greatly proceed after the forced compression force is applied. There is a problem that a large amount of force obtained by adding an amount offset by the creep phenomenon and drying shrinkage to the power compression force is required.

  In addition, at the stage where the creep phenomenon and drying shrinkage of the concrete floor slab A proceed, the concrete floor slab A is also subjected to a restraining force against deformation from the steel girder C synthesized on the lower side. In this case, a tensile force is generated.

  In the method of bending and deforming the steel girder so that the compressive force is generated on the concrete slab by lowering the fulcrum part with a jack, there is a problem in work safety when lowering the fulcrum part of a large bridge with a jack In addition, there is a problem that the management accuracy for determining the compressive force generated in the horizontal bridge axis direction of the concrete slab from the forced vertical displacement amount applied to the fulcrum is low.

  Furthermore, in the pre-stress system in which the PC steel D inserted through the concrete floor slab A is tensioned to generate a compressive force on the concrete floor slab A, the concrete floor slab A has a steel girder C on the lower side as shown in FIG. Because it is synthesized and integrated, only the concrete floor slab A needs to be compressed and deformed to give a compressive force, but an unnecessarily large compressive force that deforms the steel girder C must be applied, There is a problem that it is not economical in terms of the cost required for the construction, and there are cases where the necessary PC steel is so large that it cannot be placed in the floor slab.

  On the other hand, with respect to the composite girders that give prestress compressive force to the concrete slab, a delayed curable resin having a long curing time is provided on the contact surface between the steel girders and the concrete, as described in JP-A-2002-4475. A structure is known in which the steel girder does not restrain the concrete immediately after the concrete is placed and until a predetermined time elapses, so that a forced compressive force is effectively applied to the concrete. .

  However, at present, even though it is known that this composite girder structure has the advantage that prestress can be effectively introduced by using a delayed-curing resin between the steel girder and concrete, this structure is continuous. How can we effectively use the effectiveness of this composite girder structure in the construction method if it is used in combination with other processes in the overall construction method of the composite girder bridge? This has yet to be elucidated.

  The present invention joins a concrete slab in a non-bonded state with a steel girder as a means for solving various problems of the conventional method of applying a compressive force to the concrete slab of a continuous composite girder bridge as described above. By effectively utilizing the advantages of the composite girder structure in the overall process of the construction method of continuous composite girder bridges, effective compressive force can be applied to the concrete floor slab. The construction method of the continuous composite girder bridge is provided so that the amount of steel used is economical and the construction period can be an efficient on-site construction procedure.

  The present invention provides a concrete composite girder construction method in which a concrete compressive force is applied to a concrete floor slab on an intermediate fulcrum where a tensile force acts in the direction of the bridge axis as a concrete means for that purpose so as not to cause cracks. First, a steel girder is erected on the intermediate fulcrum part, and a concrete floor slab is constructed on the steel girder at the intermediate fulcrum part in a non-bonded state with the steel girder before applying a compressive force to the concrete slab. As the step, by proceeding with construction of steel girders in other sections other than the section provided with the concrete floor slab, placement of floor slab formwork, etc., the drying shrinkage of the concrete floor slab is advanced, and It is characterized in that a period for advancing to an age at which deformation due to a creep phenomenon is reduced is ensured, and then a forced compression force is applied to the concrete slab.

  When the concrete floor slab of the section where tensile force is generated is to be constructed at the position at the time of completion, the concrete floor slab of that section is constructed at the initial stage of the on-site construction procedure, and before applying the compulsory compression force, etc. It is preferable to secure a period of advancement to the age of the steel, in which the steel girder erection and floor slab form of the section are constructed, the drying shrinkage of the concrete floor slab is advanced, and the deformation due to the creep phenomenon is reduced .

  When a concrete floor slab in a section where tensile force is generated is divided and manufactured at a location other than the completed position such as a factory, the concrete floor slab must be It is preferable to ensure a period in which most of the drying shrinkage proceeds and the age is advanced to a material age at which deformation due to the creep phenomenon is reduced.

  Before the forced compression force is applied to the concrete slab, during the period when the drying shrinkage of the concrete slab is mostly advanced at the completion position, the restraining force of the detent for connecting the concrete slab and the steel girder and / or It is preferable that the adhesion between the concrete slab and the steel girder is suppressed.

  In addition, when a forced compressive force is applied to the concrete slab, the restraining force of the locking for connecting the concrete slab and the steel girder and / or the adhesion force between the concrete slab and the steel girder should be suppressed. preferable.

  As a means for constructing the concrete slab in a non-bonded state on the steel girder, it is preferable to interpose a delayed curable resin between the steel girder and the concrete slab. A soft plate such as rubber may be interposed between the steel girder and the concrete floor slab.

  If the span is long and it is necessary to increase the resistance to the force from the side, when installing a steel girder near the intermediate fulcrum, a concrete plate or steel and concrete are placed under the steel girder. It is good also as a structure which provides the lower floor plate which consists of a synthetic | combination version.

  In this continuous composite girder bridge construction method, first, the concrete slab is not connected to the steel girder on the steel girder at the intermediate fulcrum where the tensile force acts, that is, the concrete slab and the steel girder are cut off. Therefore, most of the drying shrinkage can be advanced without receiving the restraining force from the steel girders in the stage before the forced compressive force is applied to the concrete slab.

  As a result, when a compressive force is applied to the concrete slab as a later step, most of the above-mentioned drying shrinkage has already progressed, and the remaining drying shrinkage after progressing to a material age at which deformation due to creep phenomenon becomes small The concrete floor slab need only be given a compulsory compressive force to cancel out the small tensile force due to the creep phenomenon, the bridge surface load such as pavement and railings and the tensile force generated by the passing vehicle. It is possible to give an efficient forced compression force with a small ratio. Therefore, it is possible to reduce the amount of PC steel necessary for applying the forced compression force, and to greatly reduce the construction cost.

  The concrete floor slabs to be constructed on the steel girders at the intermediate fulcrum are divided into those manufactured by on-site construction at the completed position and those manufactured separately at locations other than the completed position, such as factories. In some cases, the material is applied at the initial stage of the on-site construction procedure, and most of the drying shrinkage is progressed until forced compression force is applied. Since it progresses to an age, construction work, such as erection of the steel girder of another area, can be efficiently advanced until that time, without generating a useless period.

  As one embodiment of the present invention, a concrete plate or a composite of steel and concrete is provided below the steel beam near the intermediate fulcrum in order to increase the resistance to the force from the lateral direction such as the wind. When a lower floor slab made of a plate is provided, the structure around this is made into a box cross section with a concrete floor slab, steel girders, lower floor slabs, etc., to increase the rigidity of the girder against the load perpendicular to the bridge axis At the same time, the load shared by the steel girders by the girder action can be reduced. Further, according to such a structure, the conventional compressing method cannot efficiently apply the forced compressive force to the concrete slab. However, in the inventive method, the forced compressing force is efficiently applied only to the concrete slab. Can be given.

  In the present invention, as described above, in the initial stage of construction, the concrete floor slab is constructed on the steel slab of the intermediate fulcrum where the tensile force is applied in a state of being uncoupled from the steel girder. Before the compression force is applied, most of the drying shrinkage proceeds under conditions that do not receive the restraining force from the steel girder, and the material age is reduced so that the deformation due to creep phenomenon is reduced. In the process of applying force, the forced compressive force can be effectively applied without waste. As a result, the concrete floor slab is not cracked, and the deterioration of the concrete floor slab is suppressed. Can do.

  In carrying out the erection method of the present invention, a steel girder is erected on the intermediate fulcrum where the tensile force acts, and after placing the concrete floor slab on the steel girder in a state uncoupled from the steel girder, As the next step, instead of applying a compulsory compressive force to this concrete slab, proceed with construction such as erection of steel girders in other sections other than the section where this concrete slab is installed, and placement of floor slab formwork. By the process, the drying shrinkage of the already placed concrete floor slab is advanced, and a period of time to advance to a material age at which deformation due to the creep phenomenon becomes small is ensured, and thereafter, a forced compressive force is applied to the concrete floor slab. .

  The construction method of the composite girder bridge according to the present invention will be described with reference to the examples shown in the drawings. FIG. 1 is a side view showing one form of construction in the initial stage of construction, and FIG. 2 is the initial stage of construction including the form of FIG. It is process drawing which showed the construction procedure until a forced compressive force is given to a concrete floor slab. As shown in FIG. 1, in this construction method, first, a steel girder 4 is constructed on an intermediate fulcrum part 3 on a pier 1 and a concrete floor slab 9 is constructed on the steel girder 4, and this concrete floor slab is constructed. In the step before applying the compulsory compressive force to 9, the span steel girder 13 is installed from both ends of the steel girder 4 toward the abutments 2 and 2 on both banks.

    Specifically, in FIG. 2, as shown in FIG. 2a, the concrete slab is forced on the intermediate fulcrum portion 3 of the pier 1 provided between the abutments 2 on both banks in a later step. An intermediate fulcrum steel beam 4 having a length corresponding to the section in which the compressive force is applied is installed.

  When the steel girder 4 is installed on the intermediate fulcrum part 3, as the next step, as shown in FIG. 2b, the installation of the scaffold 5 near the intermediate fulcrum part 3, the installation of the floor slab formwork 6, the PC steel material The construction necessary for placing the concrete slab on the steel girder 4 such as the arrangement of 7 is performed.

  In addition, in order to increase the resistance to the force from the side with a long span, in parallel with the progress of construction such as the installation of the scaffold 5, the installation of the floor slab form 6, the arrangement of the PC steel material 7, As shown in FIGS. 4 and 5, there may be a structure in which a lower floor slab 8 made of a composite plate of steel and concrete is provided below the steel beam 4 of the intermediate fulcrum 3.

  Next, as shown in FIG. 2 b, after completion of construction such as installation of the floor slab form 6 and arrangement of the PC steel material 7, a concrete floor slab 9 is placed on the steel girder 4. In placing the concrete floor slab 9, the concrete floor slab 9 is not coupled to the steel girder 4 on the steel girder 4, that is, the concrete floor slab 9 and the steel girder 4 are in a state of being cut off. Install.

  As a means for constructing the concrete floor slab 9 in a non-bonded state with the steel girder 4, for example, as shown in FIG. 10 is in a gel state when uncured, as disclosed in Japanese Patent No. 3429222, so that when the concrete shrinks due to drying, it can be freely deformed without receiving the restraining force from the steel girder 4. A delayed curable resin 11 having a property that the compressive strength changes beyond the compressive strength of concrete after being cured after a long time is used.

  When the operation of applying the delayed curable resin 11 around the stopper 10 protruding on the upper surface of the steel girder 4 becomes complicated, as shown in FIG. A delay hardening resin 11 or a rubber sheet (not shown) is laid on the flat adhesion surface so that no adhesive force is generated between the steel girder 4 and the concrete floor slab 9, and the steel girder. When the concrete floor slab 9 is placed on the upper surface of 4, a vertical hole 12 is provided around each of the stoppers 10 so as to have a space that does not contact the stoppers 10. Even if drying shrinkage occurs or prestress is applied to the concrete floor slab 9 in a later process, the steel girder 4 and the stopper 10 are configured not to give a restraining force to the deformation of the concrete floor slab 9.

  Regarding the construction of the concrete floor slab 9, the concrete floor slab 9 is placed on the spot when the construction is completed and the concrete floor slab 9 is located at a place other than the completion position such as a factory. It is conceivable that it is based on a precast method that is manufactured by dividing the product with the above method. In the case of the precast method, when manufacturing at the factory, a vertical hole 12 for inserting a stopper is prepared in advance so as to match the shape of a place to be disposed later.

  As shown in FIG. 2b, when the concrete floor slab 9 is constructed on the steel girder 4, the prestress is not continuously introduced into the concrete floor slab 9 as in the conventional construction method. As shown, the steel girder overhang is advanced so that the span steel girder 13 is sequentially connected from both ends of the steel girder 4 toward the abutment 2 on both banks.

  Then, following the construction of the interstitial steel girder 13, as shown in FIG. 2 d, construction such as installation of the scaffold 14 of the interstitial steel girder 13 and installation of the floor slab formwork 15 is performed, and subsequently, as shown in FIG. In addition, the construction necessary for the construction of other sections other than the section where the concrete floor slab 9 has already been provided, such as placing the floor slab reinforcement 16 on the interstitial steel girder 13, is advanced.

  While the construction of the interstitial steel girder 13, installation of scaffolding 14, installation of floor slab formwork 15, placement of floor slab reinforcement 16, etc., the concrete floor slab 9 has a steel girder 4 and a slippage. Due to the space of the delay curable resin 11 and the vertical hole 12 interposed between the stopper 10 and the like, a substantially edge-cut state that does not receive the adhesive force or the binding force with the steel beam 4 is obtained. Therefore, the concrete floor slab 9 advances to a material age during which most of the shrinkage during drying progresses and deformation due to the creep phenomenon becomes small.

  As described above, the concrete floor slab 9 can be constructed in either the on-site method or the precast method. FIG. 1 shows the on-site method, but the precast method is not shown. In this case, the precast floor slab is subjected to adhesion and binding force with the steel girder 4 for a predetermined period after it is erected on the steel girder 4, that is, until the construction work of the span steel girder 13 is completed. It is allowed to stand under a state where there is no edge cutting, and during that time, the drying shrinkage is sufficiently advanced, and the material is allowed to progress to a material age at which the deformation due to the creep phenomenon becomes small.

  After the installation work of the interstitial steel girder 13 has been completed, as shown in FIG. 2f, a forced compressive force is applied to the concrete slab 9 by the PC steel material 7 arranged on the concrete slab 9 above the intermediate fulcrum steel girder 4. give. At that time, as shown in FIG. 7, in the case of the construction example in which the vertical hole 12 is provided around the stopper 10 in the concrete slab 9, a mortar filling is filled in the vertical hole 12 after applying a forced compression force. Then, the floor slab and the steel girder are integrated.

  As described above, when prestress is applied to the concrete floor slab constructed on the steel girder, in the conventional construction procedure, the concrete floor slab A is coupled with the steel girder C as shown in FIG. When compressive force is applied to the plate A from both ends, the compressive force cannot be transmitted only to the concrete floor slab A, and the force to compress and deform the steel girder C must be shared.

  Also, even after the compressive force is applied, concrete undergoes shrinkage deformation due to drying shrinkage, so the amount of concrete that is finally forcibly deformed by compression shrinks from the amount of forced compression deformation given by prestress due to dry shrinkage. This is the amount excluding the amount of shrinkage of the concrete itself. That is, the forced compressive force that finally acts on the concrete is reduced by the amount of drying shrinkage that occurs after the introduction of prestress, and prestress cannot be effectively introduced.

  On the other hand, in the present invention, since the concrete floor slab 9 is constructed in a non-bonded state with the steel girder 4, a condition that does not receive the restraining force from the steel girder 4 in a stage before the forced compression force is applied. Below, most of the deformation due to creep phenomenon and drying shrinkage can proceed. Further, in the subsequent step of applying the forced compression force, the concrete floor slab 9 and the steel girder 4 are in a non-bonded state, that is, edged, so that the forced compression force is applied only to the concrete floor slab 9 as shown in FIG. The forced compression force can be effectively introduced only to the concrete floor slab 9 without requiring a useless force that deforms not only the concrete floor slab A but also the steel girder C as in the prior art.

  After prestress is introduced into the concrete floor slab 9 as shown in FIG. 2f, the concrete floor slab 19 is applied to the interstitial steel girder 13 as shown in FIG. 3g. It should be noted that the steel girder 4 on the intermediate fulcrum part 3 and the concrete slab 9 are not yet connected from the start of construction where the concrete slab 19 is constructed on the interstitial steel girder 13 until about eight months. Transition in a non-synthetic state.

  Next, as shown in FIG. 3h, the concrete floor slab 19 is subjected to bridge construction such as pavement and railing. This time is about 9 months from the start of construction. At that time, the steel girder 4 on the intermediate fulcrum 3 and the concrete slab 9 are combined, and finally the construction work is completed as shown in Fig. 3i. become.

  FIG. 9 shows the amount of shrinkage of concrete after introducing prestress by the conventional construction method and the amount of shrinkage of concrete after the introduction of prestress by the construction method of the present invention for the drying shrinkage of the concrete itself in the part where prestress is introduced. It is a figure comparing the amount of shrinkage of the concrete, but when prestress is introduced within the first month after the construction of the concrete slab, as in the conventional construction method, the concrete itself even after the prestress is introduced However, the amount of drying shrinkage with time is extremely large, and prestress is not functioning effectively.

  On the other hand, when the prestress is introduced after about 5 months from the construction of the concrete floor slab while maintaining the concrete unbonded state with the steel girder as in the construction method of the present invention, Since the concrete shrinkage has already progressed before it is introduced, if prestressing is introduced at this point, the amount of concrete shrinking afterwards will be extremely small, and a small amount of prestressed steel will effectively exert the prestress. Can be made.

  Further, FIG. 10 shows the amount of decrease in compressive force due to creep of concrete in the portion where prestress is introduced, and the amount of decrease in compressive force after introducing prestress by the conventional construction method, and the construction method of the present invention. It is a figure comparing the amount of decrease in compressive force after introducing pre-stress, but when pre-stress is introduced within one month after the construction of the concrete slab as in the conventional construction method, Even after the introduction of stress, the amount of shrinkage of concrete itself over time is large, and prestress does not function effectively.

  On the other hand, in the construction method of the present invention, the age of the concrete advances before the prestress is introduced, and the deformation due to the creep phenomenon is small, so if prestress is introduced at this point, the concrete itself will shrink due to the creep later. The amount is very small, and a small amount of prestressed steel can effectively exert prestress.

  The construction method of the continuous composite girder bridge according to the present invention is that the concrete floor slab is cut so as to be edged with the steel girder on the steel girder of the intermediate fulcrum where tensile force is generated, and then the construction work of other sections is advanced. In addition, since prestress is introduced after a time for causing creep phenomenon and drying shrinkage in the concrete slab, there is no problem in terms of construction period compared to the conventional construction method, and prestress is effectively used. It is possible to provide a practical method that can be introduced and can accurately prevent the occurrence of cracks.

The side view which shows one process of the initial stage of the construction method concerning this invention. Explanatory drawing which shows the procedure from the construction start of this erection method to prestress introduction. Explanatory drawing which similarly shows the procedure from prestress introduction to construction completion. Sectional drawing which shows the shape which provided the lower floor slab in the lower side of the steel girder of the intermediate fulcrum part. The perspective view which shows the shape which provided the lower floor slab on the steel girder of the intermediate fulcrum part. Sectional drawing of the concrete floor slab which made non-synthesizing between the steel girder and the concrete floor slab through delayed hardening resin. Sectional drawing of the concrete slab which made the non-synthesis | combination between the steel girder and the concrete slab by other means. Sectional drawing of the concrete floor slab which shows the state which introduce | transduced the prestress to the concrete floor slab by the construction method of this invention. The graph which compared the conventional construction method and the construction method of this invention about the shrinkage amount of the concrete after introduction | transduction of a prestress. The graph which compared the conventional construction method and the construction method of this invention about the reduction | decrease amount of the compressive force by the creep of concrete after the introduction of prestress. Sectional drawing of the concrete slab which shows the state which introduce | transduced the prestress to the concrete slab by the conventional construction method. Sectional drawing of the concrete slab which shows the state which gave the forced compression force in order to cancel the tensile force which arises in the concrete on an intermediate fulcrum part by the conventional construction method.

Explanation of symbols

1: Pier
2: Abutment,
3: Intermediate fulcrum part,
4: Steel girders,
5: Scaffolding,
6: Floor slab formwork,
7: PC steel
8: Lower floor version
9: Concrete slab,
10: Slip prevention,
11: Delay curable resin,
12: Vertical hole,
13: Interstitial steel girder,
14: Scaffolding
15: Floor slab formwork,
16: Floor slab reinforcement

Claims (8)

  In the construction method of a continuous composite girder in which a forced compression force is applied to the concrete slab on the intermediate fulcrum where the tensile force in the bridge axis direction acts to prevent cracking, a steel girder is first placed on the intermediate fulcrum. The concrete slab was installed on the steel girder of the intermediate fulcrum in a state where the concrete slab was not coupled to the steel girder, and the concrete slab was provided as a step before applying a compressive force to the concrete slab. By proceeding with the construction of steel girders in other sections other than the section, placement of floor slab formwork, etc., the shrinkage of the concrete floor slab is progressed, and the age is reduced until the deformation due to the creep phenomenon is reduced. A construction method for a continuous composite girder bridge, characterized in that a period is secured, and then a compressive force is applied to the concrete slab.   When the concrete floor slab of the section where tensile force is generated is to be constructed at the position at the time of completion, the concrete floor slab of that section is constructed at the initial stage of the on-site construction procedure, and before applying the compulsory compression force, etc. The continuation of claim 1 in which construction of steel girders and floor slab formwork, etc. in this section is carried out so that most of the drying shrinkage of the concrete progresses and a period of advancement to a material age at which deformation due to creep phenomenon is reduced is ensured. Construction method for composite girder bridge.   When the concrete floor slab in the section where tensile force is generated is divided and manufactured at a location other than the completion position such as a factory, the concrete shrinks before the forced compression force is applied at the completion position. The construction method of the continuous composite girder bridge according to claim 1, wherein a period of time is advanced to a material age in which most of the material is advanced and deformation due to creep is reduced.   Before the forced compression force is applied to the concrete slab, during the period when the drying shrinkage of the concrete slab is mostly advanced at the completion position, the restraining force of the detent for connecting the concrete slab and the steel girder and / or The construction method of the continuous composite girder bridge according to claim 1, wherein adhesion between the concrete slab and the steel girder is suppressed.   The continuous composite girder bridge according to claim 1, which suppresses the restraining force of the detent for connecting the concrete slab and the steel girder and / or the adhesion force between the concrete slab and the steel girder when applying a compressive force to the concrete slab. Construction method.   The construction method of the continuous composite girder bridge according to claim 1 or 4, wherein a delay curable resin is interposed between the steel girder and the concrete floor slab as a means for constructing the concrete deck in a non-bonded state on the steel girder.   6. The construction method of a continuous composite girder bridge according to claim 1 or 5, wherein a soft plate such as rubber is interposed between the steel girder and the concrete floor slab as a means for constructing the concrete slab in a non-bonded state on the steel girder. . The construction method for a continuous composite girder bridge according to claim 1, wherein a lower floor slab is provided below the steel girder when the steel girder is erected near the intermediate fulcrum.

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