Main girder continuous rigid joint structure

Abstract

Provided is a main girder continuous rigid joint structure that can reduce and appropriately bear tensile force applied to connecting concrete, and that can effectively prevent the occurrence of cracks. A main girder continuous rigid joint structure according to the present invention has a structure in which a girder end of a left-span main girder and a girder end of a right-span main girder are supported on the bridge seat surface of a common bridge pier, a bolster member being disposed between each girder end and the bridge seat surface, the girder ends of the main girders are connected to the bridge pier by respective connecting bars erected on the bridge seat surface, a support point girder member is placed above the gap formed between the girder ends of both main girders so as to leave clearance between the support point girder member and the gap, and the support point girder member, the gap, the girder ends of the main girders, and the connecting bars are embedded in concrete to connect the left-span main girder and the right-span main girder and to rigidly join the connected main girders and the bridge pier.

Description

Main girder continuous rigid joint structure

[0001] The present invention relates to a continuous rigid connection structure of the left span main girders and the right span main girders in a multi-span girder bridge in which the girder ends of multiple left span main girders arranged in parallel in the bridge width direction and the girder ends of multiple right span main girders arranged in parallel in the bridge width direction are supported on a common pier.

[0002] As shown in Figure 1 (A), a typical multi-span girder bridge has one or more piers 2 between abutments 1 on both banks depending on the bridge length, and multiple main girders 3 made of steel such as H-shaped steel or prestressed concrete are spanned in parallel across the width of the bridge between the abutment 1 and pier 2, and between piers 2 and 2, respectively, and the girder ends 3a of the main girder 3 that makes up the left span and the main girder 3 that makes up the right span are supported on the common pier 2 via bearings 6.

[0003] In such a multi-span girder bridge, as shown in Figure 1(B), a large negative bending moment (the "-" moment in Figure 1(B), i.e., a force that tries to bend the girder into an upward convex shape) is generated at the section where the girder end 3a of the left span main girder 3 and the girder end 3a of the right span main girder 3 are connected (hereinafter referred to as the "support section") due to dead loads such as the weight of the main girders and the weight of the deck concrete, or live loads such as the weight of traveling vehicles. This generates a tensile force T on the upper end of the connecting concrete 9 at this connected section, which could cause cracks.

[0004] Therefore, Patent Document 1 discloses a method in which deck concrete is poured onto the left and right span main girders, respectively, with the girder ends of the left and right span main girders not connected and a gap formed (a state in which the above-mentioned negative bending moment is not generated), and a positive bending moment (the + moment in Figure 1(B) , i.e., a force that tries to bend so as to form a downward convex shape) is generated in each main girder due to dead loads caused by the weight of each deck concrete and the weight of the main girders (hereinafter referred to as "dead loads before continuity"), and then connecting concrete is poured into the gap to connect both main girders.

[0005] JP 2008-19687 A

[0006] According to the continuous main girder structure of Patent Document 1, it is possible to prevent the generation of negative moments at the support points due to the dead load before continuity. However, when a tensile force (T in Figure 1(A)) is applied to the connecting concrete due to the dead load applied after continuity (hereinafter referred to as "dead load after continuity") or a negative bending moment due to the live load, the tensile force is borne only by the connecting concrete, that is, only by the concrete member with weak tensile strength, and the problem of cracks cannot be effectively solved.

[0007] Furthermore, in the above-mentioned Patent Document 1, as a means of preventing the connecting concrete poured in the gap from shifting, a method is adopted in which connecting members are protruded from the end faces of the girder of each main girder and embedded in the connecting concrete. However, the two connecting members are not connected to each other, and the structure is still such that the tensile force is borne by concrete members with weak tensile strength.

[0008] The present invention provides a rigidly connected continuous main girder structure that can prevent the generation of negative bending moments due to dead loads at the support points before continuity, while at the same time reducing the negative bending moments due to dead loads and live loads at the support points after continuity, and ultimately the tensile forces applied to the concrete, by having the tensile forces borne by the support point girder material located above the gap, thereby effectively solving the problem of cracks.

[0009] In summary, the continuous main girder rigidly connected structure of the present invention is a structure in which a plurality of left span main girders arranged in parallel in the bridge width direction and a plurality of right span main girders arranged in parallel in the bridge width direction are supported on a common pier to make them continuous and rigidly connected to the pier, with the girder ends of the left span main girder and the right span main girder each supported on the bridge seat of the pier via bolsters, and the girder ends of each main girder connected to the pier with connecting strips erected on the bridge seat, and a support girder is placed above the gap formed between the girder ends of both main girders at a distance from the gap, and the support girder, the gap, the girder ends of each main girder and the connecting strip are embedded in concrete to make the left span main girder and the right span main girder continuous and rigidly connect both continuous main girders to the pier.

[0010] Therefore, by not connecting the left span main girder and the right span main girder, the generation of negative bending moment due to the dead load before continuity at the support point is prevented. Meanwhile, the support point girder placed above the gap allows the support point height (H in Figure 1(A)) to be as high as possible, thereby reducing the negative bending moment due to the dead load and live load after continuity at the support point and reducing the tensile force applied to the concrete. In addition, the tensile force is borne by the support point girder, effectively eliminating the problem of cracks.

[0011] Preferably, by making each of the main girders arch-shaped, the support height can be reliably increased and the negative bending moment due to the dead load and live load after the continuation can be reduced.

[0012] Preferably, by connecting the support beams to the connecting strips, the support beams can be easily positioned at desired locations and the continuous rigid connection structure can be strengthened.

[0013] Furthermore, by using a metal beam for the support part, it is possible to appropriately bear the tensile force.More preferably, by using a reinforcing bar for the support part beam, it is possible to easily install and embed the beam.

[0014] Alternatively, the support beams can be made of prestressed concrete (hereinafter referred to as "PC").

[0015] Preferably, the girder support surface of the pillow material has a curved or polygonal structure, so that it can reliably support each of the main girders while appropriately adapting to the displacement, inclination, and shape of each of the main girders.

[0016] Furthermore, by connecting the upper end of the connecting bar to a support material above the support beam and fixing a nut to the upper surface of the support material via a spherical washer, the spherical washer can absorb the inclination due to the longitudinal gradient and transverse gradient, allowing the nut to be fixed without any gaps.

[0017] The main girder continuous rigid connection structure of the present invention prevents the occurrence of negative bending moments due to the dead load before continuity at the support point, while reducing the negative bending moments due to the dead load and live load after continuity at the support point, and ultimately the tensile force applied to the connecting concrete, and allows the support point girder material to bear the reduced tensile force, thereby effectively preventing the occurrence of cracks.

[0018] 5A is a side view showing a typical multi-span girder bridge, and FIG. 5B is a distribution diagram of bending moments occurring in a multi-span girder bridge. This is an explanatory diagram showing a main girder continuous rigid connection structure in an embodiment using steel angle bars as support girders. This is an explanatory diagram showing the state in which each girder end of the left span main girder and the right span main girder is connected to a pier. This is an explanatory diagram showing the state in which each girder end of the left span main girder and the right span main girder is connected to a pier. This is a cross-sectional view in the bridge length direction showing the main girder continuous rigid connection structure. This is a cross-sectional view of the main girder continuous rigid connection structure in a plan view (cross-sectional view along line A-A in FIG. 5). This is a cross-sectional view of the main girder continuous rigid connection structure in a plan view (cross-sectional view along line B-B in FIG. 5). This is a cross-sectional view in the bridge width direction showing the main girder continuous rigid connection structure (cross-sectional view along line C-C in FIG. 5). This is a cross-sectional view explaining a bolster member with a polygonal girder support surface. 11(a)-11(c) are explanatory diagrams outlining a main girder continuous rigid connection structure in an embodiment in which reinforcing bars are used as support girder materials. FIG. 11(a) is a cross-sectional view in the bridge length direction showing a main girder continuous rigid connection structure. FIG. 11(b) is a cross-sectional view in a plane of a main girder continuous rigid connection structure (cross-sectional view along line D-D in FIG. 11). FIG. 11(c) is a cross-sectional view in a plane of a main girder continuous rigid connection structure (cross-sectional view along line E-E in FIG. 11). FIG. 11(c) is a cross-sectional view in the bridge width direction showing a main girder continuous rigid connection structure (cross-sectional view along line F-F in FIG. 11). FIG. 11(c) is a cross-sectional view explaining the fixing of nuts using spherical washers. FIG. 11(c) is a cross-sectional view in the bridge length direction showing another example of a main girder continuous rigid connection structure.

[0019] Hereinafter, the best embodiment of the continuous main girder rigidly connected structure according to the present invention will be described with reference to Figs.

[0020] <General continuous main girder structure> As mentioned above, as shown in Figure 1 (A), a general double-span girder bridge has one or more piers 2 between abutments 1 on both banks depending on the length of the bridge, and multiple main girders 3 made of steel such as H-shaped steel or prestressed concrete are installed in parallel across the width of the bridge between the abutment 1 and pier 2, and between the piers 2 and pier 2, respectively.

[0021] In more detail, the girder ends 3a of the main girders 3 that make up the left span and the main girders 3 that make up the right span are supported via bearings 6 on the bridge seat 2a of one pier 2, and a gap 5 is formed between the girder ends 3a of the left span main girders 3 and the right span main girders 3, specifically between the girder end faces 3b of each girder end 3a, and this gap 5 gives the left span main girders 3 and right span main girders 3 a discontinued structure, and connecting concrete 9 is poured into the gap 5 to make the left span main girders 3 and right span main girders 3 continuous.

[0022] <Continuous main girder rigidly connected structure according to the present invention> <Basic structure> As shown in Figures 2 and 10, the continuous main girder rigidly connected structure according to the present invention has a structure in which the girder end 3a of the left span main girder 3 and the girder end 3a of the right span main girder 3 are each supported on the bridge bearing surface 2a of a common pier 2 via pillow members 4, and the girder end 3a of each main girder 3 is connected to the pier 2 by connecting bars 13 erected on the bridge bearing surface 2a.

[0023] In the present invention, the girder end 3a of the left span main girder 3 and the girder end 3a of the right span main girder 3 are particularly left unconnected, and a support girder 7 is placed above the gap 5 formed between the girder end faces 3b of each girder end 3a, at a distance from said gap 5, and the support girder 7, gap 5, girder ends 3a of each main girder 3 and connecting strips 13 are embedded in connecting concrete 9 to connect the left span main girder 3 and the right span main girder 3, and to rigidly connect the connected main girders 3 to the piers 2, providing a basic structure.

[0024] Therefore, the main girder continuous rigid connection structure of the present invention, like a general continuous structure, does not connect the girder ends 3a of the left span main girder 3 and the right span main girder 3, and therefore of course can prevent the occurrence of negative bending moments due to pre-continuity dead loads at the support points, but it also has the following effects.

[0025] That is, the support beam 7 is buried above the gap 5 at a distance from the gap 5, making it possible to make the support height H as high as possible, thereby reducing the negative bending moment due to the dead load and live load at the support after continuity and reducing the tensile force T applied to the connecting concrete 9. In addition, the tensile force T can be borne by the support beam 7, effectively solving the problem of cracks.

[0026] 2 to 8 and 16 show examples in which steel angle bars are used as the support girder 7, while Figs. 10 to 14 show examples in which reinforcing bars are used as the support girder 7. As will be described later, in the continuous main girder rigid connection structure according to the present invention, the girder used as the support girder 7 may be made of metal or precast concrete as long as it can withstand the tensile force T, and the cross-sectional shape may also be arbitrary depending on the implementation.

[0027] <<Main Girder Structure>> In the present invention, it is desirable to use an arch-shaped main girder for each main girder 3. For example, as shown in Figures 2 and 10, a curved arch-shaped main girder, i.e., a main girder with an upwardly convex curved shape in the longitudinal direction, is used for each main girder 3. This curved arch shape reliably increases the support height H and reduces the negative bending moment due to the dead load and live load after continuation, thereby reducing the tensile force T. Furthermore, as shown in Figure 16, if a square arch-shaped (π-shaped) main girder is used for each main girder 3, i.e., a main girder in which the height of the central girder in the longitudinal direction is higher than the height of the end girder portions, the square arch shape also reliably increases the support height H and thereby reduces the tensile force T.

[0028] In each example in this document, an example is shown in which an H-shaped steel beam is used as the main girder 3, but the cross-sectional shape is not particularly important as long as the girder is made of metal, preferably steel, and has a support surface that is supported by the bolster material 4 described below and a flange portion that can be connected to the vertically extending connecting strip 13. Furthermore, when a curved arch shape is used, the radius (R) that determines the arc shape can be adjusted as appropriate, and when a square arch shape is used, the angle of the corners can be adjusted as appropriate.

[0029] <<Main girder support structure and rigid connection structure between girders and piers>> In the continuous main girder rigid connection structure of the present invention, as shown in Figures 3 and 4, first, the left span main girder 3 and the right span main girder 3 are supported by pillow members 4 installed on the bridge bearing surface 2a of a common pier 2 that supports the left span main girder 3 and the right span main girder 3, respectively.

[0030] To explain the bolster 4 in more detail, the bolster 4 is made of concrete, metal, or synthetic resin, and is arranged continuously across the width of the bridge as shown in Figures 8 and 14. Preferably, the girder support surface (upper surface) 4a of the bolster 4 has a curved structure as shown in Figure 5, or as shown in Figure 9, the girder support surface 4a has a polygonal structure consisting of many small width surfaces 4b, so that it can support each main girder 3 in response to its inclination or deformation.

[0031] Therefore, as shown in Figure 4, when the girder ends 3a of the left span main girder 3 and the right span main girder 3 are supported by the lower flanges 3e on the bridge bearing surface 2a of the pier 2 via the bolster 4 installed as described above, the curved or polygonal girder support surface 4a of the bolster 4 can absorb any tilt of the main girder 3, and since it does not have any sharp or right-angled corners, it can effectively prevent the bolster 4 itself from chipping.

[0032] In addition, in the present invention, connecting strips 13 that connect to each girder end 3a of the left span main girder 3 and the right span main girder 3 are erected on the bridge seat 2a on which the above-mentioned bolsters 4 are installed.

[0033] The connecting bar 13 is formed of a steel rod such as a reinforcing bar, and the lower end of the steel rod is embedded integrally in the concrete pier 2 and extends from the bridge bearing surface 2a. Alternatively, a cable can be used instead of a steel rod.

[0034] When steel rods are used as connecting bars 13, as shown in Figures 5 and 10, the ends of the reinforcing bars 16 embedded in the concrete pier 2 can be protruded upward from the bridge seat 2a, and the protruding parts can be used as connecting bars 13.

[0035] 3, the connecting strips 13 are inserted through the girder ends 3a of the left span main girder 3 and the right span main girder 3. Specifically, they are inserted from bottom to top through insertion holes 17 provided in the upper flanges 3d and lower flanges 3e of the girder ends 3a of the left span main girder 3 and the right span main girder 3. It is desirable to make the insertion holes 17 elongated in the direction of the bridge length so that they can accommodate displacement or misalignment of the girder ends 3a of the main girders 3.

[0036] 8 and 14, the connecting strips 13 can be raised on the bridge bearing surface 2a from directly below the girder end 3a of each main girder 3, and also from directly below the parallel spacing in the bridge width direction (the spacing between main girders 3 adjacent in the bridge width direction) of the girder end 3a of each main girder 3. Alternatively, it is also possible to raise the connecting strips 13 only from directly below the girder end 3a of each main girder 3 on the bridge bearing surface 2a, depending on the implementation.

[0037] Furthermore, as mentioned above, when connecting strips 13 are provided that rise from directly below the parallel spacing in the bridge width direction of the girder end 3a of each main girder 3, the connecting strips 13 are inserted within the parallel spacing as shown in Figures 8 and 14.

[0038] As shown in Figures 3 and 4, when steel angle bars are used as the support girder 7, the support girder 7 can be easily positioned at the desired location above the gap 5 by using connecting bars 13 inserted into the girder ends 3a of each main girder 3. That is, a nut 14' supporting the underside of the flange 7a of the support girder 7 is screwed onto the upper end (male thread end) of the connecting bar 13, and the upper end is inserted into a through-hole 7d protruding from the flange 7a. A nut 14 is then screwed onto the inserted upper end, and the nut 14 is fixed to the upper surface of the flange 7a of the support girder 7, thereby fixing the support girder 7 in the desired position. Note that reference numeral 21 in Figure 3 denotes a washer.

[0039] The nuts 14 fixed to the upper surfaces of the flanges 7a of the support girder 7 described above are fixed directly to the upper surface of the flange 7a, or as shown in the figure, are fixed to the upper surface of the flange 7a via bearing members 15. The bearing members 15 extend across the girder ends 3a arranged in parallel in the bridge width direction, and are placed on the upper surfaces of the flanges 7a of the support girder 7.

[0040] As shown in Figures 8 and 14, the upper ends of the connecting bars 13 inserted within the parallel spacing (adjacent spacing) in the bridge width direction of the left span main girder 3 and within the parallel spacing (adjacent spacing) in the bridge width direction of the right span main girder 3 are inserted through the portions 15a of the bearing material 15 that extend between the main girders 3, and nuts 14 are screwed onto them, and the nuts 14 are fixed to the upper surface of the bearing material portions 15a.

[0041] 3 and 4 show an embodiment in which steel angle bars are used as the support girder members 7, but in the case of the embodiment shown in FIG. 10 etc. in which reinforcing bars are used as the support girder members 7, the left span main girder 3 and the right span main girder 3 are similarly supported by the bolster members 4, and the connecting strip members 13 connecting to each girder end 3a are inserted into the through holes 17 of each girder end 3a.

[0042] Also, as shown in Figure 11, when steel bars are used as the support beams 7, the upper ends of the connecting bars 13 that penetrate the girder ends 3a of each main girder 3 are inserted into the support material 15, and nuts 14 are screwed onto them, and the nuts 14 are fixed to the upper surface of the support material 15.

[0043] Furthermore, regardless of whether the support beam 7 is an angle bar or a rebar, when fixing the nut 14 to the top surface of the bearing member 15, as described above, it is preferable to fix it via a washer 21 as shown in Figure 15. The washer 21 shown in Figure 15 is a spherical washer, consisting of a pair of washers, an upper washer 21a and a lower washer 21b, and the engagement between the convex spherical portion on one washer and the concave spherical portion on the other washer allows the nut 14 to be fixed without any gaps, appropriately responding to inclinations due to longitudinal gradients, transverse gradients, etc.

[0044] <Support girder structure> As mentioned above, the support girder 7 is arranged above the gap 5 formed between the girder end faces 3b of the left span main girder 3 and the right span main girder 3, with a gap between them, and is embedded in the connecting concrete 9 described below.It is a component that bears the tensile force T applied to the connecting concrete 9 and contributes to preventing cracks.

[0045] The support beam 7 can be made of metal or precast concrete, regardless of its shape, as long as it can bear the tensile force within the connecting concrete 9. For example, as shown in Figures 2 to 8, steel angle bars with a T-shaped cross section can be used, as well as angle bars with various cross-sectional shapes such as H-shaped, I-shaped, and π-shaped.

[0046] Alternatively, as shown in Figures 10 to 14, reinforcing bars extending in the longitudinal direction of the bridge can be used as the support beams 7. Preferably, the assembly reinforcement of the concrete deck 8 can be used to easily and appropriately position the support beams 7.

[0047] In the present invention, the length of the support girder 7 can be adjusted as appropriate, provided that it can be placed and embedded in the portion of the connecting concrete 9 where tensile stress occurs. That is, as shown in Figures 2 and 5, the support girder 7 can be made long enough to cover only the vicinity of the support, or as shown in Figures 10 and 11, the support girder 7 can be made long enough to cover the entire length of the bridge.

[0048] <Bridge Body Concrete Structure> Next, the structure of the bridge body concrete will be explained. The bridge body concrete is poured onto each main girder 3 and within the parallel intervals between each main girder 3 in the bridge width direction.

[0049] First, concrete deck 8 (bridge body concrete) is poured onto the left span main girder 3 and the right span main girder 3, and concrete slab 18 (bridge body concrete) is poured within the parallel spacing between the left span main girder 3 in the bridge width direction and within the parallel spacing between the right span main girder 3.

[0050] At this time, the girder end 3a of each main girder 3 is displaced due to an increase in dead load (dead load before continuity), but this displacement is absorbed by the through-holes 17. Furthermore, the curved or polygonal shape of the girder support surface 4a of each bolster 4 also contributes to absorbing the displacement of the girder end 3a of each main girder 3. Therefore, the occurrence of negative bending moment due to deformation of each main girder 3 by the dead load before continuity caused by the pouring of bridge body concrete is prevented.

[0051] Describing concrete pouring in detail, slab concrete 18 is poured into the space defined by the upper and lower flanges 3d, 3e and web 3c of the left span main girder 3 adjacent in the width direction of the bridge, and then the deck concrete 8 is poured onto the left span main girder 3. Similarly, slab concrete 18 is poured into the space defined by the upper and lower flanges 3d, 3e and web 3c of the right span main girder 3 adjacent in the width direction of the bridge, and then the deck concrete 8 is poured onto the right span main girder 3.

[0052] In other words, the opening 19' extending in the bridge length direction and formed between the lower flanges 3e adjacent in the bridge width direction of the left span main girder 3 is closed with a closing member, and slab concrete 18 is poured into the space through the opening 19 extending in the bridge length direction and formed between the upper flanges 3d adjacent in the bridge width direction of the left span main girder 3, and then the deck concrete 8 is poured onto the left span main girder 3.

[0053] Similarly, an opening 19' extending in the bridge length direction and formed between adjacent lower flanges 3e in the bridge width direction of the right span main girder 3 is closed with a closing member, and slab concrete 18 is poured into the space through an opening 19 extending in the bridge length direction and formed between adjacent upper flanges 3d in the bridge width direction of the right span main girder 3, and then deck concrete 8 is poured onto the right span main girder 3.

[0054] <Interlocking concrete structure> Finally, formwork is assembled and interlocking concrete 9 is poured onto the bridge bearing surface 2a of the pier 2 through the gap 5, and the gap 5, the girder ends 3a of the left span main girder 3 and the right span main girder 3, the support girder members 7 and the interlocking strip members 13 are embedded in the interlocking concrete 9.

[0055] Preferably, the connecting concrete 9 is poured before the bridge body concrete (the deck concrete 8 and the slab concrete 18) that has been poured as described above hardens, so that the connecting concrete 9 and the bridge body concrete harden in a good, intimate manner.

[0056] After the connecting concrete 9 has hardened, paving 20 is applied to complete the continuous rigidly connected main girder structure shown in FIGS. 5 to 8 and 11 to 14.

[0057] As explained above, in the present invention, by disconnecting the girder end 3a of the left span main girder 3 from the girder end 3a of the right span main girder 3, it is possible to prevent the occurrence of negative bending moments due to the dead load before continuity.

[0058] After the continuation, a tensile force is applied to the upper portion of the connecting concrete 9 due to a negative bending moment based on the live load acting on the left span main girder 3 and the right span main girder 3 or the dead load after the continuation, such as the weight of the pavement 20. However, in the present invention, this tensile force is reduced by making the support height H as high as possible, and the reduced tensile force is appropriately borne by the support girder 7, effectively preventing cracks from occurring in the connecting concrete 9.

[0059] Furthermore, in the present invention, between the girder ends 3a of the left span main girders 3 adjacent in the width direction of the bridge, a plurality of connecting wires 10 made of steel wire such as PC cable or solid wire extending in the width direction of the bridge are inserted at intervals in the length direction of the bridge through insertion holes 11 drilled in each girder end 3a and embedded in the connecting concrete 9, and, between the girder ends 3a of the right span main girders 3 adjacent in the width direction of the bridge, a plurality of other connecting wires 10 made of the above-mentioned steel wire extending in the width direction of the bridge are inserted at intervals in the length direction of the bridge through insertion holes 11 drilled in each girder end 3a and embedded in the connecting concrete 9, thereby strengthening the rigid connection structure of the continuous main girders.

[0060] To restate, as shown in Figures 8 and 14, the connecting wire 10 is inserted through the through-holes 11 so as to penetrate the webs 3c at the girder ends 3a of each main girder 3, which is made of H-shaped steel arranged in parallel in the width direction of the bridge, and is fastened with nuts 12 on the outer surfaces of the webs 3c at the girder ends 3a of the main girders 3 at both ends in the width direction of the bridge.

[0061] Alternatively, although not specifically shown, connecting wires 10 can be loosely inserted into pipe material extending in the width direction of the bridge between the girder ends 3a of the left span main girders 3 adjacent in the width direction of the bridge and embedded in the connecting concrete 9, and connecting wires 10 can be loosely inserted into other pipe material extending in the width direction of the bridge and embedded in the connecting concrete 9 between the girder ends 3a of the right span main girders 3 adjacent in the width direction of the bridge, and by tensioning the connecting wires 10, prestress can be applied to the connecting concrete 9, thereby reinforcing it.

[0062] Furthermore, by inserting a large number of connecting wires 10 or connecting wires 10 loosely inserted into connecting pipes at intervals along the length of the bridge through each web 3c of the left span main girder 3 and the right span main girder 3, it is possible to apply prestress to the slab concrete 18 and reinforce it.

[0063] 8, when angle irons are used as the support girders 7, insertion holes 7c are protruded into the webs 7b of the support girders 7, and connecting wires 10 or connecting wires 10 loosely inserted into connecting pipes are passed through the insertion holes 7c so as to penetrate the webs 7b of each of the support girders 7 arranged in parallel across the width of the bridge, and are fastened with nuts 12 on the outer surfaces of the webs 7b of the support girders 7 at both ends across the width of the bridge. This also applies prestress to the connecting concrete 9, thereby reinforcing it.

[0064] Furthermore, as shown in Figure 14, when steel bars are used as support beams 7, it is possible to use steel bars extending perpendicular to the support beams 7 as connecting wires 10 to connect all of the support beams 7 arranged in parallel across the width of the bridge, thereby reinforcing the support beams 7 themselves.

[0065] DESCRIPTION OF SYMBOLS 1...Abutment, 2...Pier, 2a...Bridge seat, 3...Main girder (left span main girder, right span main girder), 3a...Girder end, 3b...Girder end face, 3c...Web, 3d...Upper flange, 3e...Lower flange, 4...Pillow, 4a...Girder support surface, 4b...Narrow width surface, 5...Gap, 6...Bearing, 7...Support girder, 7a...Flange, 7b...Web, 7c...Insertion hole, 7d...Penetration hole, 8...Deck concrete (bridge body concrete), 9...Connecting concrete, 10...Connecting wire, 11...Through hole, 12...Nut, 13...Connecting strip, 14, 14'...Nut, 15...Bearing material, 15a...Bearing material part, 16...Reinforcing steel, 17...Penetration hole, 18...Slab concrete (bridge body concrete), 19, 19'...Opening, 20...Pavement, T...Tensile force, H...Support height.

Claims

1. A structure in which multiple left span main girders arranged in parallel in the direction of the bridge width and multiple right span main girders arranged in parallel in the direction of the bridge width are supported on a common pier to make them continuous and rigidly connected to the pier, wherein the girder ends of the left span main girders and the girder ends of the right span main girders are supported on the bridge seat of the pier via pillow members, and the girder ends of each main girder are connected to the pier with connecting strips erected on the bridge seat, and a support girder is placed above the gap formed between the girder ends of both main girders, with a gap between them, and the support girder, the gap, the girder ends of each main girder and the connecting strips are embedded in concrete to make the left span main girders and the right span main girders continuous and rigidly connect both continuous main girders to the pier.

2. The continuous rigidly connected main girder structure according to claim 1, wherein each of said main girders is arch-shaped.

3. The main girder continuous rigidly connected structure according to claim 1, characterized in that the support beams are connected to the connecting strips.

4. The main girder continuous rigid joint structure according to claim 1, characterized in that the support part girder material is made of metal.

5. A continuous main girder rigidly connected structure according to claim 4, characterized in that the support beams are made of steel bars.

6. The continuous main girder rigidly connected structure according to claim 1, characterized in that the support beams are made of prestressed concrete.

7. The main girder continuous rigid joint structure according to claim 1, characterized in that the girder support surface of the pillow material has a curved or polygonal surface structure.

8. A main girder continuous rigid connection structure as described in claim 1, characterized in that the upper end of the connecting strip is connected to a support material above the support point girder, and a nut is fixed to the upper surface of the support material via a spherical washer.

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