JP6660646B2 - Steel slab bridge - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a deck slab bridge applied to new construction or replacement, and relates to a steel slab bridge mainly made of steel.

  Conventionally, a relatively small-scale bridge uses a floor slab bridge using a concrete girder, a composite slab bridge formed by combining steel shell and concrete (for example, Patent Document 1). In recent years, a slab bridge (for example, Patent Literature 2) in which a plurality of square steel pipes are joined to form a slab has been provided.

  Another type of bridge that does not use concrete as a main component is a steel deck bridge.

  For these small bridges, it is necessary to carry out close visual inspections within a period of five years or less as a form of maintenance by law. In addition, depending on the result of the diagnosis after the inspection, it may be necessary to replace the structure. Therefore, it is important to provide a structure that allows accurate visual diagnosis.

JP 05-222707 A JP 2005-330809 A

  Conventional concrete slab bridges are relatively small-scale bridges with short spans, but can be quite heavy. There is a problem that the substructure is relatively large and the total cost increases.

  Synthetic floor slab bridges can form an effective member cross section by combining steel shell and concrete, and have the advantage of reducing their own weight and girder height, but the steel shell that constitutes the main member covers the bottom Since it is formed, it is difficult to confirm the filling state of the concrete located on the back side (upper side) of the bottom steel shell, and the back side of the bottom steel shell cannot be directly visually recognized by the naked eye in maintenance. Therefore, there is a problem that it is difficult to grasp the damage state, which leads to an increase in inspection cost, such as necessity of advanced inspection technology.

  In the case of square steel pipe deck bridges, if a plurality of square steel pipes arranged in parallel are damaged due to fretting, for example, on each side that comes into contact with each other, it cannot be confirmed visually, and ultrasonic thickness measurement technology It is difficult to recognize even by using a corrosion detection technique based on the like. In addition, since a temporally hardenable material such as concrete is filled into the inside of the steel pipe when forming the slab unit, there is a problem similar to that of the synthetic slab bridge in terms of maintenance.

  The floor slab bridge, whose main components are made of a time-hardening material such as concrete, has been completed by forming an integral structure, and if severe damage occurs partially due to aging, etc. Since it is difficult to replace various members, there is a problem that the repair cost increases.

  Also, in the structure using a relatively long time hardening material such as concrete for the main member, it is necessary to secure a certain curing period to obtain a predetermined strength, the construction period tends to be longer, There is a problem that is an obstacle when aiming for early completion such as replacement.

  The steel floor slab is a stiffening plate in which vertical ribs and horizontal ribs are welded to the lower surface of a deck plate that forms a floor surface, and has problems in processing cost and fatigue durability.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made of a steel frame structure and a grid formed by bolts without using a material constituting a main member and a relatively long-time hardening material such as concrete for a connecting portion. An object of the present invention is to provide a steel slab bridge in which a floor surface made of a non-stiffened plate is provided on the upper surface of a girder. In addition, when arranging the main steel members, it is possible to prevent the occurrence of fretting damage etc. due to contact between members by securing a certain interval, and even if damage occurs due to other factors, the damage is prevented. A steel deck slab bridge that can be found at an early stage using corrosion detection techniques such as visual inspection and ultrasonic waves, and that can be repaired in a short time and at low cost by making it possible to replace a specific narrow range of members The challenge is to provide

  In order to solve the above-mentioned problem, the invention according to claim 1 includes at least two iron main girders installed so as to extend in the longitudinal direction toward the bridge axis direction and adjacent main girders. An iron deck plate placed so as to straddle, an iron bolt having a head at one end of a male screw portion, and an iron nut screwed into the male screw portion, and a head of the bolt Connecting means for pressing and connecting a plurality of mutually stacked members disposed between the nut and the nut, wherein the main girder includes an upper flange Au and an upper flange Au And a web Aw orthogonal to the upper flange Au and the lower flange Ad. The upper surface of the upper flange Au is disposed at a position corresponding to the lower surface of the deck plate. H A through hole is formed in a portion where the deck plate and the upper flange Au overlap each other, and a through hole penetrating the overlapping portion is formed. And the nut is screwed into the male screw portion protruding from the through hole.

  According to a second aspect of the present invention, in the first aspect of the present invention, between the adjacent main girders, each position of both ends in the longitudinal direction of the main girders and at least one position between the both ends. Is provided with an iron horizontal girder extending over the adjacent main girder and connected to the adjacent main girder. The horizontal girder includes an upper flange Bu and a lower part of the upper flange Bu. , And a web Bw orthogonal to the upper flange Bu and the lower flange Bd, and the upper surface of the upper flange Bu is disposed at a position corresponding to the lower surface of the deck plate. An iron gusset plate formed of an H-shaped steel frame and formed on the main girder at a position corresponding to the web Bw of each of the cross beams so as to partially overlap the web Bw. g is welded, a through hole is formed in a portion where the deck plate and the upper flange Bu overlap each other, and a portion where the web Bw and the gusset plate Ag overlap with each other is formed. Also, a through-hole penetrating the overlapping portion is formed, and the connecting means is arranged at a position of each of the through-holes, and a male screw portion of each of the bolts is inserted into each of the through-holes. Each of the nuts is screwed to each of the male screw portions projecting from each of the through holes.

  According to a third aspect of the present invention, in the first aspect of the present invention, between the adjacent main girders, each position of both ends in the longitudinal direction of the main girders and at least one position between the both ends. Is provided with an iron horizontal girder extending over the adjacent main girder and connected to the adjacent main girder. The horizontal girder includes an upper flange Bu and a lower part of the upper flange Bu. , And a web Bw orthogonal to the upper flange Bu and the lower flange Bd, and the upper surface of the upper flange Bu is disposed at a position corresponding to the lower surface of the deck plate. The main girder is formed of an H-shaped steel frame, and is formed on the main girder at a position corresponding to the web Bw of each of the cross girders so as to partially abut against an end surface of the web Bw. iron The gusset plate Ag is welded, and the gusset plate Ag and the web Bw of the cross beam are provided with an iron attachment plate As having a shape partially overlapping both the gusset plate Ag and the web Bw. Ag and the web Bw are overlapped with each other, and in a portion where the deck plate and the upper flange Bu overlap each other, a through hole penetrating the overlapping portion is formed, and the gusset plate Ag and the attachment plate As are provided. Also, a through hole passing through these overlapping portions is formed in a portion where the web Bw overlaps with the supporting plate As, and also in a portion where the web Bw and the attachment plate As overlap with each other, and the connecting means is disposed at a position of each of the through holes. The male screw portion of each of the bolts is inserted into each of the through holes, and each of the nuts protrudes from each of the through holes. Serial is characterized by being screwed to each male screw portion.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the space between the adjacent main beams extends over the adjacent beam and is connected to the adjacent beams. A vertical stringer made of iron is provided, and the stringer is orthogonal to the upper flange Cu, the lower flange Cd located below the upper flange Cu, and the upper flange Cu and the lower flange Cd. And an upper surface of the upper flange Cu is formed by an H-shaped steel frame arranged at a position corresponding to a lower surface of the deck plate, and the cross beam is provided on the web Cw of each of the vertical beams. At a corresponding position, an iron gusset plate Bg formed so as to partially overlap the web Cw is welded, and the deck plate and the upper flange Cu overlap each other. Is formed with a through-hole penetrating the overlapping portion, and at a portion where the web Cw and the gusset plate Bg overlap each other, a through-hole penetrating the overlapping portion is formed. A male screw portion of each bolt is inserted into each through hole, and each nut is screwed to each male screw portion protruding from each through hole. It is characterized by having.

  The invention according to claim 5 is the invention according to claim 2 or 3, wherein the space between the adjacent main girders extends over the adjacent horizontal girder and is connected to the adjacent horizontal girder. A vertical stringer made of iron is provided, and the stringer is orthogonal to the upper flange Cu, the lower flange Cd located below the upper flange Cu, and the upper flange Cu and the lower flange Cd. And an upper surface of the upper flange Cu is formed by an H-shaped steel frame arranged at a position corresponding to a lower surface of the deck plate, and the cross beam is provided on the web Cw of each of the vertical beams. At the corresponding position, an iron gusset plate Bg formed so as to partially abut against the end face of the web Cw is welded, and the gusset plate Bg and the gusset of the stringer are welded. On the gusset plate Bg and the web Cw, an iron attachment plate Bs having a shape partially overlapping both of the gusset plate Bg and the web Cw is superimposed on the gusset plate Bg and the web Cw. Are formed in portions where the gusset plate Bg and the supporting plate Bs overlap each other, and in a portion where the web Cw and the supporting plate Bs overlap each other. Also, a through hole penetrating these overlapping portions is formed, the connecting means is arranged at the position of each of the through holes, and the male screw portion of each of the bolts is inserted into each of the through holes, Each of the nuts is screwed to each of the male screw portions projecting from each of the through holes.

  According to a sixth aspect of the present invention, there is provided the main girder, the deck plate and the connecting means according to any one of the first to fifth aspects, and the cross beam and the gusset plate according to any one of the second to fifth aspects. Ag, the attachment plate As according to any one of claims 3 to 5, the stringer and the gusset plate Bg according to any one of claims 4 to 5, or the attachment plate Bs according to claim 5. , Each of which is covered with a hot-dip galvanized layer.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to seventh aspects, a waterproof layer is provided so as to cover at least an entire surface of a higher portion of the main girder above the upper surface of the upper flange Au. The asphalt pavement layer is provided directly or indirectly on the upper side of the waterproof layer.

  The invention according to claim 8 is the invention according to claim 7, characterized in that the waterproof layer is constituted by at least one of a waterproof coating and a waterproof sheet.

  According to the invention described in claim 1, at least two iron main girders extending in the longitudinal direction toward the bridge axis direction are provided, and the main girders are connected to the upper flange Au, the lower flange Ad, and the web Aw. Each main girder has a large bending rigidity in the vertical direction based on the H-shaped steel frame so as to oppose the bending moment even when, for example, a vertical bending moment acts as an external force, since it is constituted by the H-shaped steel frame. Can be suppressed as much as possible in the vertical deformation of the bridge.

  For example, assuming that the longitudinal ends of each main girder are supported from below, and a load such as an automobile or the like acts on the middle part in the longitudinal direction of the main girder downward, the main girder has a middle part in the longitudinal direction. The bending moment that causes the bridge to bend downward is exerted. However, each main girder has a large bending rigidity in the vertical direction, so that the bridge can be prevented from being bent downward.

  That is, the vertical bending stiffness of the main girder can be represented by (E × I). (E) is the longitudinal elastic modulus, and (I) is the second moment of area in the vertical direction. In this case, the vertical moment of inertia (I) tends to increase in proportion to the square of the distance from the horizontal neutral axis to the upper flange Au and the lower flange Ad in a cross section orthogonal to the longitudinal direction of the main girder. Together with the upper flange Au and the lower flange Ad. Therefore, the bending stiffness in the vertical direction of the main girder made of the H-shaped steel frame can be made extremely large, so that the bending of each main girder downward due to the bending moment can be reduced.

  In addition, since the deck plate is connected to the upper surface of the upper flange Au in a state of being pressed by the connecting means, the deck plate and the upper flange Au are integrally connected with a large frictional force. . For this reason, an external force such as a bending moment acting on the deck plate can be held by the main girder and the deck plate, and the external force can be dispersed evenly throughout the bridge.

  Accordingly, since the bending deformation of the entire bridge can be suppressed as small as possible, it is possible to contribute to the improvement of the running stability of the automobile and the like, and to improve the durability of the bridge itself. The calculation of the second moment of area of the bridge is based on only the main girder which is a strength member, but the deck plate integrally connected to the upper flange Au of the main girder by the connecting means is also used. This is one factor that increases the second moment of area in the vertical direction of the bridge. That is, by connecting the deck plate to the upper flange Au by the connecting means, the bending rigidity of the bridge can be substantially improved.

  In addition, the upper flange Au of the main girder and the deck plate are integrally connected with each other with a frictional force when tightened by a connecting means having bolts and nuts, and there is no room for relative movement. It is possible to reliably suppress the occurrence of fretting corrosion and the like caused by delicate rubbing at the portions.

  Moreover, since the structure is not designed to improve the strength by filling the lower part of the deck plate and other parts with concrete or the like, the surface of each main girder, the lower surface of the deck plate, etc. is corroded by oxidation or the like. Even when rust occurs, its corrosion can be found early by visual inspection or the like, and the corroded portion can be easily repaired. Further, there is an advantage that the corrosion generated on the upper surface of the deck plate can be found from the lower surface side by using a corrosion detection technique such as ultrasonic waves.

  On the other hand, since the main girder, the deck plate, and the connecting means for connecting the main girder and the deck plate are provided, the main girder and the deck plate can be processed into a predetermined shape at a factory or the like. Therefore, at the site where the bridge is to be constructed, the main work is to place the processed main girder and deck plate at a predetermined position and then connect them using the connecting means, thus improving the safety of work. In addition, the construction period can be shortened, the construction cost can be reduced, and the like. For this reason, for example, there is an advantage that the replacement of a bridge whose service life has expired can be performed in a very short time and at low cost.

  Also, for example, even if a specific part of the bridge is damaged due to corrosion, accident, etc., by replacing the main girder and deck plate in the minimum necessary range corresponding to the damaged part, it will be extremely short time and low cost. There is an advantage that it can be repaired with.

  Furthermore, since the structure does not use concrete for improving the strength, there is no need to consider the curing time, and the construction period can be shortened accordingly. In addition, since the weight of the strength members can be reduced, it is not necessary to arrange large-scale heavy equipment, so that the construction period can be shortened and the total cost can be reduced.

  Further, since the deck plate is not a stiffened plate formed by welding longitudinal ribs or the like, the cost required for welding or the like can be reduced, and the fatigue durability of the deck plate can be improved.

  According to the invention as set forth in claim 2, an iron cross beam connected to an adjacent main girder is provided at each position of both ends in the longitudinal direction of the main girder and at least one position between the both ends, The cross beam is formed by an H-shaped steel frame having an upper flange Bu, a lower flange Bd, and a web Bw, and the upper flange Bu and the deck plate are connected in a state of being pressed by the connecting means, so that, for example, an Even if the axle weight of the car acts on the deck plate between the mating main girders, thereby applying a bending moment to bend the deck plate downward, an external force such as this bending moment is applied to the deck plate to apply the transverse girder. Can also be supported by

  In this case, since the horizontal girder has a large bending rigidity in the vertical direction similarly to the main girder, it is possible to minimize the downward bending deformation of the deck plate between the adjacent main girder. In addition, since the contact portion between the cross beam and the deck plate is connected in a state of being pressed by the connecting means, there is no relative fine movement fluctuation, and therefore no fretting corrosion or the like. .

  Further, since the superposed portion of the gusset plate Ag welded to the main girder and the web Bw of the cross girder are connected in a state of being pressed by the connecting means, the main girder and the cross girder reduce the frictional force. And a firmly connected state is formed. Therefore, an integrated and strong steel slab bridge can be obtained by the main girder, the cross girder and the deck plate, and external forces such as loads and bending moments of automobiles acting on the deck plate are averaged over the entire bridge. Can be dispersed. Therefore, since the bending deformation of the entire bridge can be suppressed to a smaller value, it is possible to more stably support an automobile or the like and further improve the durability of the bridge itself. Further, fretting corrosion or the like does not occur at the contact portion between the gusset plate Ag of the main girder and the web Bw of the horizontal girder.

  According to the third aspect of the present invention, the gusset plate Ag and the butt plate As are provided with the iron attachment plate As having a shape that partially overlaps both the gusset plate Ag and the web Bw of the cross beam. Since the overlapping portion and the portion where the web Bw and the attachment plate As overlap with each other are connected by the connection means, by using more connection means corresponding to the size of the attachment plate As, the main girder and The connection strength with the cross beam can be improved. In addition, fretting corrosion or the like does not occur in the contact portion between the gusset plate Ag and the attachment plate As and in the contact portion between the web Bw and the attachment plate As.

  According to the invention as set forth in claim 4, an iron vertical girder connected to an adjacent horizontal girder is provided between adjacent main girders, and the upper flange Cu, the lower flange Cd, and the web Cw are provided as the vertical girder. Since the upper flange Cu and the deck plate can be connected in a state of being pressed by the connecting means using the H-shaped steel frame having the H-shaped steel frame, an external force such as a bending moment or the like for bending the deck plate between the adjacent main girders downward. Can be supported by stringers in addition to deck plates and cross beams.

  In this case, since the vertical girder also has a large bending rigidity in the up-down direction, the downward bending moment generated between the adjacent main girders can reduce the bending deformation of the deck plate downward. Further, the contact portion between the stringer and the deck plate is also connected in a state of being pressed by the connecting means, so that there is no relative fluctuation and no fretting corrosion. .

  Further, since the overlapped portion of the gusset plate Bg welded to the cross beam and the web Cw of the vertical beam is connected by being pressed by the connecting means, the horizontal beam and the vertical beam reduce the frictional force. And a firmly connected state is formed. Therefore, an integrated and strong steel slab bridge can be obtained by the main girder, the cross girder, the girder and the deck plate, and the external force such as the load of the automobile or the like acting on the deck plate or the bending moment can be obtained. It can be dispersed evenly throughout. Therefore, since the bending deformation of the entire bridge can be further suppressed, the vehicle and the like can be extremely stably supported, and the durability of the bridge itself can be further improved. Further, fretting corrosion or the like does not occur at the contact portion between the horizontal girder and the vertical girder.

  According to the fifth aspect of the present invention, there is provided the iron attachment plate Bs having a size that partially overlaps both the gusset plate Bg and the webs Cw of the stringers. Since the overlapped portion and the overlapped portion of the web Cw and the attachment plate Bs are connected to each other in a state where they are pressed against each other by the connection means, more connection means are required based on the size of the attachment plate Bs. It can be used, and the connection strength between the horizontal girder and the vertical girder can be improved. In addition, fretting corrosion does not occur in the contact portion between the gusset plate Bg and the attachment plate Bs and in the contact portion between the web Cw and the attachment plate Bs.

  According to the invention described in claim 6, the main girder, the deck plate and the connecting means according to any one of claims 1 to 5, the cross beam and the gusset plate Ag according to any one of claims 2 to 5, The attachment plate As according to any one of claims 3 to 5, the stringer and the gusset plate Bg according to any one of claims 4 to 5, or the attachment plate Bs according to claim 5, each having an entire surface. Since it is covered with any one of the hot-dip galvanized layer, the predetermined coating layer, and the layer in which the predetermined coating layer is overlaid on the hot-dip galvanized layer, it is possible to obtain a steel floor slab bridge having an extremely high rust prevention effect. .

  According to the invention as set forth in claim 7, a waterproof layer is provided so as to cover at least the entire surface of a high portion above the upper surface of the upper flange Au of the main girder, and an asphalt pavement layer is provided above the waterproof layer. Therefore, it is possible to prevent rainwater or the like from reaching the deck plate or the like via the asphalt pavement layer. Therefore, the rust prevention effect of the deck plate and the like can be improved.

  Also, while the rigidity of the bridge is increased by the main girder, etc., the elasticity of the road surface is improved by the asphalt pavement layer, so both the stability and the ride comfort of the car when passing through the bridge are improved. Can be improved, and at the same time, impact and noise when a vehicle passes can be reduced. Further, asphalt pavement has an extremely short curing time as compared with concrete pavement, and is therefore advantageous in shortening the construction period.

  According to the eighth aspect of the present invention, since the waterproof layer is made of a waterproof coating or a waterproof sheet, it is possible to sufficiently waterproof the corners. In addition, when the asphalt pavement layer is repaired, there is an advantage that the waterproof layer can be repaired as needed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the steel slab bridge shown as one Embodiment of this invention. It is a disassembled perspective view which shows the same steel slab bridge. It is a top view in the state where the deck plate which shows the steel frame deck bridge was removed. It is a figure which shows the principal part of the same steel deck slab, (a) is sectional drawing which follows the IV-IV line of FIG. 3, (b) is a deck plate above the main girder etc. in (a). It is sectional drawing which shows the state which installed, (c) is sectional drawing which shows the state which installed the asphalt pavement layer and the ground cover on the upper side of the deck plate in (b). It is a figure which shows the principal part of the same steel deck slab, (a) is sectional drawing which follows the VV line of FIG. 3, (b) is a deck plate above the main girder etc. in (a). It is sectional drawing which shows the state which installed, (c) is sectional drawing which shows the state which installed the asphalt pavement layer and the ground cover on the upper side of the deck plate in (b). It is a figure which shows the principal part of the same steel floor slab bridge, (a) is a principal part top view which shows the VI section of FIG. 3, (b) is sectional drawing which follows the BB line in (a). FIG. 4C is a cross-sectional view taken along the line CC in FIG. 4B, and FIG. 4D is a cross-sectional view taken along the line DD in FIG. It is a figure which shows the principal part of the steel frame deck bridge, (a) is principal part top view which shows the VII part of FIG. 3, (b) is sectional drawing which follows the BB line in (a). FIG. 4C is a cross-sectional view taken along the line CC in FIG. 4B, and FIG. 4D is a cross-sectional view taken along the line DD in FIG. It is a figure which shows the principal part of the steel frame deck bridge, (a) is a principal part top view which shows the VIII part of FIG. 3, (b) is sectional drawing which follows the BB line in (a). FIG. 3C is a cross-sectional view taken along line CC in FIG. It is a figure which shows the principal part of the steel frame deck bridge, (a) is a principal part top view which shows the IX part of FIG. 3, (b) is sectional drawing which follows the BB line in (a). FIG. 3C is a cross-sectional view taken along line CC in FIG.

  A steel slab bridge shown as an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, at least two steel slab bridges 1 shown in this embodiment are installed so as to extend in the longitudinal direction in the bridge axis direction X (in this embodiment, six steel bridges). ), And an iron deck plate 3 placed so as to straddle the adjacent main girder 2.

  The main girder 2 includes an upper flange Au21 having a predetermined width, a lower flange Ad22 having the same width as the upper flange Au21, and a web Aw23 connecting a central portion of the upper flange Au21 and the lower flange Ad22 in the width direction. Is formed by a rolled H-shaped steel for welded structure (H-shaped steel frame) having an H-shaped cross section. The upper flange Au21 is formed parallel to the lower flange Ad22, and the web Aw23 is formed to be orthogonal to the upper flange Au21 and the lower flange Ad22.

  As shown in FIGS. 1 to 4, the deck plate 3 is formed in a planar shape by a rolled steel plate for general structure having a predetermined thickness, has a rectangular shape in plan view, and has a longitudinal direction. Is formed to a size equivalent to the length of the main girder 2, and the widthwise dimension is formed so as to cover a portion of the pair of adjacent main girder 2 that is less than half the width of each upper flange Au 21. Have been. The deck plate 3 is configured such that each end in the width direction (that is, each side end) is evenly overlapped with a half of the width of the upper flange Au21 of each adjacent main girder 2 in the width direction. In this state, each of the upper flanges Au21 is connected to the upper flange Au21 by a connecting means 4 utilizing a tightening force of an iron bolt and an iron nut.

  The bolt has a hexagonal column-shaped head at one end of the male screw portion, and the nut has a female screw hole at the axial center portion of the hexagonal columnar body to be screwed into the male screw portion. . The connecting means 4 is configured to connect a plurality of stacked members arranged between the head portion of the bolt and the nut screwed to the male screw portion thereof in a pressed state. The connecting means 4 may include a flat washer, a spring washer, and the like in addition to the bolt and the nut.

  In this case, a plurality of through-holes penetrating coaxially are formed at each side end of each upper flange Au21 and the deck plate 3 placed on the upper flange Au21, and the connecting means 4 is connected to each of the through-holes. A male screw part of a bolt is inserted into each, and a nut is screwed and screwed into a male screw part protruding from each through hole so that the deck plate 3 and the upper flange Au21 are strongly pressed and connected to each other. Has become.

  In addition, the six main girders 2 shown in this example are arranged in parallel at regular intervals so that the webs Aw23 are parallel to each other, and the upper surfaces of the upper flanges Au21 are on the same plane (in this example, (Horizontal plane). That is, the upper flange Au21 of each main beam 2 supports each deck plate 3 on its upper surface, thereby holding each deck plate 3 at a position on the same plane.

  Outer than the outermost main girder 2 among the six main girder 2 arranged in parallel in this way, an outer girder 200 having the same length as the main girder 2 has a main girder at the outermost position. It is installed in parallel with the girder 2 at a predetermined interval.

  The outer girder 200 includes an upper flange Du201 having a predetermined width, a lower flange Dd202 having the same width as the upper flange Du201, and a web connecting one end of the upper flange Du201 and the lower flange Dd202 in the width direction. Dw 203 is formed of a U-shaped rolled channel steel for welded structure (channel steel) having a U-shaped cross section, and the web Dw 203 is installed so as to be located on the main girder 2 side at the outermost position. In this case, the web Dw203 of the outer girder 200 is parallel to the web Aw23 of the main girder 2, and the upper surface of the upper flange Du201 of the outer girder 200 is flush with the upper surface of the upper flange Au21 of the main girder 2. It is becoming.

  An outer deck plate 30 made of iron is placed on the main girder 2 at the outermost position and the outer girder 200 outside the main girder 2 so as to straddle them. The outer deck plate 30 is formed of a rolled steel plate for general structure similar to the deck plate 3 and is formed in a rectangular shape, and has the same thickness and length as the deck plate 3, but has a width Are narrower than the deck plate 3.

  That is, the outer deck plate 30 has one side end placed on the upper surface of a part of the main girder 2 that is slightly less than half the width of the upper flange Au 21 in the main girder 2, and the other side end located above the outer girder 200. The dimension in the width direction is set so as to be placed on the entire upper surface of the flange Du201, and the respective side ends are connected to the upper flange Au21 and the upper flange Du201 by the connecting means 4. . In this case, the upper flange Au21 of the main girder 2 and the outer deck plate 30 thereon, as well as the upper flange Du201 of the outer girder 200 and the outer deck plate 30 thereabove, have a plurality of through holes coaxially penetrating therethrough. Is formed. The connecting means 4 inserts a male screw portion of a bolt into each of the through holes, and screws and fastens a nut to a male screw portion protruding from each of the through holes, so that the outer deck plate 30 and the upper flange Au21, Further, the outer deck plate 30 and the upper flange Du201 are strongly pressed and connected to each other.

  On the other hand, as shown in FIG. 3, between each adjacent main girder 2, each position of both ends in the longitudinal direction of the main girder 2 and at least one position between both ends (in this embodiment, both ends At three positions that divide the space into four equal parts), there is provided an iron horizontal girder 5 extending over the adjacent main girder 2 and connected to the adjacent main girder 2. That is, the cross beam 5 shown in this embodiment is oriented in a bridge axis orthogonal direction (a direction orthogonal to the bridge axis direction X) Y in which the longitudinal direction extends between the main beams 2.

  As shown in FIGS. 4, 6, and 8, the cross beam 5 includes an upper flange Bu51 having a predetermined width, a lower flange Bd52 having the same width as the upper flange Bu51, and an upper flange Bu51 and a lower side. The flange Bd52 is formed of a rolled H-shaped steel for welded structure (H-shaped steel) having an H-shaped cross section by a web Bw53 connecting the central portion in the width direction of the flange Bd52, and the upper flange Bu51 is connected to the deck plate 3 by the connection means 4. I have. In this case, a plurality of through-holes penetrating coaxially are formed in the upper flange Bu51 and the deck plate 3 placed on the upper flange Bu51, and the connecting means 4 includes a male bolt. The deck plate 3 and the upper flange Bu51 are strongly pressed and connected to each other by inserting a screw portion and screwing and tightening a nut to a male screw portion projecting from each through hole. I have.

  On the other hand, between the outermost main girder 2 at each outermost position and the outer girder 200 outside the outer girder, an iron outer horizontal girder 500 connecting the main girder 2 and the outer girder 200 is provided in each longitudinal direction of the main girder 2. It is installed at a position corresponding to the cross beam 5. Each outer cross beam 500 is formed of a rolled H-shaped steel for general structural use (H-shaped steel frame) having an upper flange Eu501, a lower flange Ed502, and a web Ew503 connecting the upper flange Eu501 and the lower flange Ed502. The upper flange Eu501 is connected to the outer deck plate 30 by the connecting means 4. However, FIGS. 6 (a), 7 (a), 8 (a) and 9 (a) show the connection means 4 without showing the deck plate 3 or the outer deck plate 30. I have. The outer cross beam 500 has the same cross-sectional shape and dimensions as the cross beam 5. However, the outer cross beam 500 has a dimension in the longitudinal direction (axial direction) shorter than that of the cross beam 5. The outer cross beam 500 is connected to the outer deck plate 30 in a state where the upper flange Eu 501 is strongly pressed against the outer deck plate 30 by the connection means 4, similarly to the cross beam 5.

  Further, as shown in FIG. 3, one of the horizontal beams 5 located at the center in the longitudinal direction of the main beam 2 is a distribution horizontal beam 05. As shown in FIG. 5 and FIG. 7, the distribution cross beam 05 has a bending rigidity in the vertical direction that is greater than that of the other cross beams 5. That is, as shown in FIGS. 4 and 6, the height of the web Bw53 of each ordinary horizontal beam 5 is about 程度 of the height of the web Aw23 of the main beam 2, while the distribution horizontal beam is shown. 5, the height of the web Ew053 is set to be substantially the same as the height of the web Aw23 of the main girder 2 as shown in FIGS. However, the upper flange Eu051 and the lower flange Ed052 of the distribution cross beam 05 have the same shape and dimensions as the upper flange Bu51 and the lower flange Bd52 of the cross beam 5. The axial lengths of the horizontal beams 5 and the distribution horizontal beams 05 are the same. In this example, the width of the upper flange Bu51 and the upper flange Eu051 is about half the width of the upper flange Au21 of the main girder 2.

  As for each outer cross beam 500, the outer cross beam 0500 is located at the center of the main girder 2 in the longitudinal direction. The outer cross beam 0500 has the same cross-sectional shape as the distribution cross beam 05. In addition, the axial lengths of the outer cross beams 500 and the outer cross beams 0500 are the same. Here, the reason why the outer horizontal beam 0500 is not set to the distribution outer horizontal beam 0500 is that the outer horizontal beam is not considered as an element having a distribution effect in the analysis of the strength or the like. However, since the outer cross beam 0500 has the same cross-sectional shape as the distribution cross beam 05, it substantially has a distribution effect and contributes to improvement in strength. Further, the outer cross beam 0500 has the same cross-sectional shape as the distribution cross beam 05 because the gusset plate Ag24 described later is used at the central position in the longitudinal direction of the main girder 2 without using the gusset plate Ag24 described later. This makes it possible to match the shapes of all the main girders 2 and to take into account the workability in manufacturing and erection. A gusset plate Ag24 described later may be provided at a central position in the longitudinal direction of the main girder 2, and the outer horizontal girder 500 may be provided via the gusset plate Ag24.

  As shown in FIGS. 4 and 6, each cross beam 5 except the distribution cross beam 05 is connected to an iron gusset plate Ag24 whose web Bw53 is welded to each main beam 2. . That is, a gusset plate Ag24 formed so as to partially overlap the web Bw53 is welded to the main girder 2 at a position corresponding to the web Bw53 of each horizontal girder 5 except the distribution horizontal girder 05. ing.

  The gusset plate Ag24 is located between the upper flange Au21 and the lower flange Ad22 that protrude to one side of the web Aw23 in the main girder 2, and is along the inner surfaces of these upper flange Au21, lower flange Ad22, and web Aw23. One flat plate-shaped rolled steel plate for a welding structure, comprising: a holding portion 24a formed in a square shape; and a connecting portion 24b projecting from the holding portion 24a in a square shape further outward than the upper flange Au21 and the lower flange Ad22. Is formed by The gusset plate Ag24 has the holding portion 24a vertically applied to the upper flange Au21, the lower flange Ad22, and the web Aw23, and each applied side portion thereof is attached to the upper flange Au21, the lower flange Ad22, and the web Aw23. Welded. The gusset plate Ag24 is welded to both sides of the web Aw23 in the main girder 2.

  The connecting portion 24b of the gusset plate Ag24 is connected to the web Bw53 of the cross beam 5 by the connecting means 4 in a state where the connecting portion 24b overlaps the web Bw53. In this case, a through-hole penetrating coaxially is formed at each of the four corners of the rectangular portion where the connecting portion 24b and the web Bw53 overlap, and the connecting means 4 is provided at each of the through-holes. The male screw portion of the bolt is inserted, and a nut is screwed into a male screw portion protruding from each through-hole and tightened, whereby the connecting portion 24b and the web Bw53 are strongly pressed and connected. . In the state where the connecting means 4 are connected, the upper surface of the upper flange Bu51 of each cross beam 5 is positioned on the same plane as the upper surface of the upper flange Au21 of the main beam 2, so that the connecting means 4 The position and size of each through hole through which the bolt passes are set.

  On the other hand, as shown in FIGS. 5 and 7, the webs Ew053 are adjacent to each other via the distribution gusset plate Ag024 made of iron and the attachment plate As025 made of iron welded to each main girder 2 as shown in FIGS. It is connected to the main girder 2. That is, the main girder 2 is welded with the iron distribution gusset plate Ag024 formed so that a part thereof is brought into close contact with the end face of the web Ew053 of each distribution horizontal girder 05.

  The distribution gusset plate Ag024 is located between the upper flange Au21 and the lower flange Ad22 projecting to one side of the web Aw23 in the main girder 2, and is a square along the inner surfaces of the upper flange Au21, the lower flange Ad22, and the web Aw23. Is formed by a flat-plated rolled steel sheet for a welding structure. The distribution gusset plate Ag024 is vertically applied to the upper flange Au21, the lower flange Ad22, and the web Aw23, and the three applied sides are welded to the upper flange Au21, the lower flange Ad22, and the web Aw23. The outer side portion 024a, which is another side portion, extends linearly so as to vertically connect the tips of the upper flange Au21 and the lower flange Ad22, and is close to the end face of the web Ew053 of each distribution cross beam 05. It is formed so that it may be in a state of being abutted. The distribution gusset plate Ag024 is welded to both sides of the web Aw23 in the main girder 2.

  The attachment plate As025 is formed of a flat plate-shaped rolled steel plate for general structural use having a size sized to partially overlap both the distribution gusset plate Ag024 and the web Bw053 of the distribution cross beam 05. The two attached plates As025 are installed so as to be evenly overlapped on both sides of the web Bw053 and the distribution gusset plate Ag024, and are connected to the web Bw053 and the distribution gusset plate Ag024 by the connection means 4. Has become.

  In this case, a through-hole that penetrates coaxially is formed at each of the four corners of the quadrangular portion where the two attachment plates As025 and the web Bw053 overlap each other. A male screw portion of a bolt is inserted into each of the holes, and a nut is screwed into a male screw portion protruding from each of the through holes to fasten the two auxiliary plates As025 to the web Bw053. It is designed to be connected. Similarly, the two overlapping plates As025 and the distribution gusset plate Ag024 are connected to each other in a state where the portions overlapping in a square shape are strongly pressed by the connecting means 4. The size of the portion where the attachment plate As overlaps in a square shape is equal between the distribution gusset plate Ag024 side and the web Bw053.

  In a state where each distribution cross beam 05 is connected to each main girder 2 via the attachment plate As025, the upper surface of the upper flange Bu051 of each distribution cross girder 05 is flush with the upper surface of the upper flange Au21 of the main girder 2. The position and the size of each through hole through which the bolt of the connecting means 4 passes are set so that the position can be set.

  As shown in FIG. 4 and FIG. 8, each outer cross beam 500 except the outer cross beam 0500 has a web Ew 503 on each of the gusset plate Ag24 of the main girder 2 and the iron gusset plate Dg204 of the outer girder 200. In an overlapping state, they are connected by the connecting means 4. The gusset plate Dg204 is formed of a single flat-plated rolled steel plate for a welding structure having a square shape, and one side thereof is welded to the outer surface of the web Dw203 of the outer girder 200 facing the main girder 2 side. I have. In this case, the gusset plate Dg204 has its plate surface oriented perpendicular to the longitudinal direction (axial direction) of the outer girder 200. The gusset plate Dg204 is connected to the web Ew503 of the outer cross beam 500 by the connecting means 4 in a state where the gusset plate Dg204 is overlapped with the web Ew503.

  In this case, a through-hole penetrating coaxially is formed at each of the upper and lower positions of the square portion where the gusset plate Dg 204 and the web Ew 503 are overlapped, and the connecting means 4 The male screw portion of the bolt is inserted into each, and the nut is screwed into the male screw portion protruding from each through-hole and tightened, so that the gusset plate Dg204 and the web Ew503 are strongly pressed and connected. ing. On the other hand, the web Ew 503 and the gusset plate Ag 24 are connected by the connecting means 4 in the same manner as in the case of the horizontal beam 5 described above. Then, in a state in which the outer cross girder 500 and the outer girder 200 are connected to the outermost main girder 2, the upper surface of the upper flange Eu 501 of each outer girder 500 and the upper surface of the upper flange Du 201 of the outer girder 200 are the main girder. The position and size of each through-hole through which the bolt of the connecting means 4 passes are set so that the upper surface of the second upper flange Au21 can be located on the same plane.

  As shown in FIG. 5 and FIG. 9, the web Fw0503 of the outer horizontal girder 0500 is connected to the main girder 2 by the connecting means 4 via the distribution gusset plate Ag024 and the attachment plate As025 in the same manner as the distribution horizontal girder 05. It is to be connected to. In addition, the web Fw0503 of the outer cross beam 0500 is connected to the outer girder 200 by the connecting means 4 via the gusset plate Dg204, similarly to the outer cross beam 500.

  On the other hand, between the adjacent main girders 2, as shown in FIG. 3, extending over the adjacent horizontal girder 5 or extending across the horizontal girder 5 and the distribution horizontal girder 05. An iron vertical girder 6 connected to the horizontal girder 5 and the distribution horizontal girder 05 is provided. In other words, the longitudinal girder 6 shown in this embodiment is mainly connected with each end in the axial direction (longitudinal direction) to the central part in the axial direction (longitudinal direction) of the horizontal girder 5 and the distribution horizontal girder 05. It is provided so as to extend in parallel with the spar 2.

  As shown in FIGS. 3 to 9, the stringer 6 includes an upper flange Cu61 having a predetermined width, a lower flange Cd62 having the same width as the upper flange Cu61, and an upper flange Cu61 and a lower flange Cd62. The upper flange Cu61 is connected to the deck plate 3 by the connecting means 4 and is formed of a rolled H-shaped steel for general structure (H-shaped steel frame) having a web Cw63 connecting the central portion in the width direction. In this case, a plurality of through-holes penetrating coaxially are formed in the upper flange Cu61 and the deck plate 3 placed on the upper flange Cu61, and the connecting means 4 is provided with male bolts in each of the through-holes. The deck plate 3 and the upper flange Cu61 are strongly pressed and connected to each other by inserting a screw portion, screwing a nut into a male screw portion protruding from each through hole and tightening the nut. I have.

  The vertical girder 6 is connected by the connecting means 4 with the web Cw 63 partially overlapped on the iron gusset plate Bg 54 welded to the horizontal girder 5 or the distribution horizontal girder 05. It has become so. That is, a gusset plate Bg54 having a shape capable of partially overlapping with the web Cw63 of each of the vertical girders 6 is welded to the horizontal girder 5 and the distribution horizontal girder 05 at the center in the longitudinal direction.

  As shown in FIG. 6D, the gusset plate Bg54 is located between the upper flange Bu51 and the lower flange Bd52 projecting to one side of the web Bw53 in the cross beam 5, and these upper flange Bu51 and lower flange B51. A holding portion 54a formed in a square shape along the inner surfaces of the Bd52 and the web Bw53, and a connecting portion 54b projecting from the holding portion 54a in a square shape further outward than the upper flange Bu51 and the lower flange Bd52. It is formed of a single flat rolled steel plate for a welding structure (iron plate). The gusset plate Bg54 is in a state where the holding portion 54a is vertically applied to the upper flange Bu51, the lower flange Bd52, and the web Bw53. It is to be welded. The gusset plate Bg54 is welded to both sides of the web Bw53 in the cross beam 5.

  The gusset plate Bg54 is also formed on the distribution beam 05, as shown in FIG.

  The connecting portion 54b of the gusset plate Bg54 is connected to the web Cw63 of the vertical beam 6 by the connecting means 4 in a state where the connecting portion 54b overlaps the web Cw63. In this case, a through-hole that penetrates coaxially is formed at each of the four corners of the rectangular portion where the connecting portion 54b and the web Cw63 overlap each other. The connecting portion 54b and the web Cw63 are strongly connected to each other by inserting a male screw portion of the bolt into the male screw portion and screwing and tightening a nut to the male screw portion projecting from each through hole. ing. In the state where the upper flanges Cu61 of the vertical girders 6 are connected by the connecting means 4, the upper surfaces of the upper flanges Cu61 can be flush with the upper surfaces of the upper flanges Au21 of the main girders 2. The position of the hole is set.

  As for the connection between the distribution girder 05 and the column girder 6, the distribution gusset plate Bg (not shown) welded to the distribution girder 05 and the web Cw63 of the column girder 6 are attached to the attachment plate Bs (not shown). It may be configured to be connected by the connecting means 4 via the. In this case, the distribution gusset plate Bg has the same configuration as the distribution gusset plate Ag024, and the attachment plate Bs has the same configuration as the attachment plate As025.

  As shown in FIG. 7, an iron support plate 26 is welded to a portion of each main girder 2 corresponding to the distribution horizontal girder 05, at the widthwise edge of the lower flange Ad22. The support plate 26 is formed of a flat-plated rolled steel plate for a welding structure having a trapezoidal shape, and the bottom side of the long side is welded to the edge of the lower flange Ad22, thereby forming the lower side. It extends in the same direction as the flange Ad22.

  The support plate 26 is positioned so as to overlap with the lower surface of the lower flange Bd052 of the distribution cross beam 05 in a state where the distribution cross beam 05 is connected to the distribution gusset plate Ag024 of the main girder 2. The entire short side of the upper side is located so as to cover the entire width of the lower flange Bd052 in the width direction. Further, the portion where the support plate 26 and the lower flange Bd052 overlap is connected by the connecting means 4. That is, a plurality of through-holes penetrating coaxially are formed in a portion where the support plate 26 and the lower flange Bd052 overlap, and the connecting means 4 inserts a male screw portion of a bolt into each of the through-holes. Then, by screwing and tightening a nut to a male screw portion protruding from each through hole, the support plate 26 and the lower flange Bd052 are strongly pressed and connected.

  As shown in FIG. 3, the cross-sectional shape of the main girder 2 outside the horizontal girder 5 located at each end of the main girder 2 is the same as that of the vertical girder 6 and the axial length of the main girder 2 is smaller than that of the vertical girder 6 A short short stringer 60 is provided. The short vertical girder 60 is connected to the gusset plate Bg54 of the horizontal girder 5 by using the connecting means 4 like the vertical girder 6. As shown in FIGS. 4 and 5, an iron reinforcing plate 205 is welded to the outer girder 200 at a position corresponding to the horizontal girder 5 and the distribution horizontal girder 05. The reinforcing plate 205 is formed of a rectangular flat plate-shaped rolled steel plate for a welding structure welded to the inner surfaces of the upper flange Du201, the lower flange Dd202, and the web Dw203.

  The main girder 2, the gusset plates Ag24, 024, the attachment plate As025, the support plate 26, the outer girder 200, the gusset plate Dg204, the reinforcing plate 205, the deck plate 3, the outer deck plate 30, the bolts and nuts as the connecting means 4, etc. For the horizontal beam 5, including the distribution horizontal beam 05, the gusset plate Bg54, the external horizontal beam 500, the external horizontal beam 0500, the vertical beam 6, the short and long vertical beam 60, and all other members described above, The entire surface is covered with a hot-dip galvanized layer. In addition, the hot-dip galvanizing is applied to the members to which welding has been performed in a state after welding.

  As shown in FIGS. 4 and 5, the main girder 2, the outer girder 200, the horizontal girder 5, the vertical girder 6, the deck plate 3, the outer deck plate 30 and the like are connected by the connecting means 4, so that the entire steel structure is reduced. In the completed state, a waterproof layer (not shown) is provided so as to cover at least the entire surface of the upper part of the main girder 2 above the upper surface of the upper flange Au21, and the asphalt pavement layer 81 is overlapped with the waterproof layer. Is provided.

  That is, the waterproof layer is formed on the upper surface of the upper flange Au21 in the main girder 2 between the deck plates 3, the upper surface of the upper flange Au21 between the deck plate 3 and the outer deck plate 30, the deck plate 3 and the outer deck plate 30. It is provided so as to cover at least the portion from the side surface to the upper surface, the connecting means 4 exposed on the upper surfaces of the deck plate 3 and the outer deck plate 30. In this case, it goes without saying that a waterproof layer may be provided below the upper surface of the upper flange Au21. The waterproof layer is formed into a layer using one or both of a waterproof coating and a waterproof sheet.

  On the waterproof layer, a ground covering 82 extending in the bridge axis direction X is provided at each end in the bridge axis orthogonal direction Y. The ground cover 82 is installed in a portion from the main girder 2 to the outer girder 200 at the outermost position, and enables, for example, installation of a protective fence. The asphalt pavement layer 81 is installed between the ground coverings 82 on the waterproof layer and in a range reinforced by the main girder 2, the horizontal girder 5, the distribution horizontal girder 05, the vertical girder 6, and the like.

  The main girder 2, the deck plate 3, and the outer deck plate 30 have an axial length of about 10 m in this example, and can be transported by a vehicle. In this case, the bridge length or span length is also about 10 m. The total width of the bridge is set to about 7 m in this example. The total width of the bridge can be freely changed by increasing or decreasing the main girder 2 or the like.

  In the steel slab bridge 1 configured as described above, a plurality of main girders 2 extending in the longitudinal direction (axial direction) in the bridge axis direction X are provided, and each main girder 2 is attached to the upper flange Au21 and the lower girder. Since it is made of a rolled H-section steel for a welding structure having a side flange Ad22 and a web Aw23, for example, both ends of the main girder 2 in the longitudinal direction are supported from below, and an automobile is provided at an intermediate portion of the main girder 2 in the longitudinal direction. When a load such as is applied downward, a bending moment acts to bend the main girder 2 downward, but with a large bending rigidity in the vertical direction based on each main girder 2 against the bending moment. Can compete.

  That is, the bending stiffness of the main girder 2 in the vertical direction can be represented by (E × I). (E) is the longitudinal elastic modulus, and (I) is the second moment of area in the vertical direction. In this case, the vertical moment of inertia (I) in the vertical direction is substantially proportional to the square of the distance from the horizontal neutral axis to the upper flange Au21 and the lower flange Ad22 in the cross section perpendicular to the longitudinal direction of the main girder 2. And increases in proportion to the sectional area of each of the upper flange Au21 and the lower flange Ad22. Therefore, a large bending rigidity in the vertical direction of the main girder 2 can be obtained, so that the amount of downward bending of each main girder 2 due to the bending moment can be reduced as much as possible.

  In addition, the deck plate 3 is integrally connected to the upper surface of the upper flange Au21 via a frictional force by a connecting means 4 using a tightening force of a bolt and a nut, and relatively moves with the upper flange Au21. Since there is no room and the position is far away from the above-mentioned neutral axis, it greatly contributes to the increase in the bending rigidity.

  Therefore, it is possible to withstand a large bending rigidity against the external force caused by the bending moment that causes the intermediate portion in the bridge axis direction to bend downwardly, and to suppress the downward bending deformation of the bridge extremely small. it can.

  In addition, since the upper flange Au21 of the main girder 2 and the deck plate 3 have no room for relative movement, it is possible to reliably prevent the occurrence of fretting corrosion or the like caused by delicate rubbing between steel materials. In addition, since the lower part of each main girder 2 is not covered with concrete or the like, the surface other than the fretting above the main girder 2, the horizontal girder 5, the distribution horizontal girder 05, the vertical girder 6 and the lower surface of the deck plate 3 is provided. Even if corrosion due to oxidation or the like occurs, the corrosion can be visually detected at an early stage. In addition, the corrosion of the upper surface of the deck plate 3 due to oxidation or the like can be advantageously detected from the lower surface side of the deck plate 3 at an early stage by using a corrosion detection technique such as ultrasonic waves.

  Further, the outermost main girder 2 and the outer girder 200, the outer horizontal girder 500, the outer horizontal girder 0500, the outer deck plate 30 and the like disposed outside the main girder 2 are integrally connected by the connecting means 4 with frictional force. Therefore, it is possible to reliably prevent fretting corrosion and the like from occurring at the contact portions. Further, the lower part of the outer deck plate 30 is not filled with concrete, and the outer girder 200, the outer cross girder 500 and the like are exposed. Even in the case of corrosion due to oxidation or the like, it can be found early by visual inspection or the like.

  On the other hand, the main girder 2, the horizontal girder 5, the distribution horizontal girder 05, the vertical girder 6, the deck plate 3, the outer girder 200, and the like are assembled on site by the connecting means 4 to complete all of the skeleton portions which are the strength members of the bridge. Therefore, the main girder 2, the horizontal girder 5, the distribution horizontal girder 05, the vertical girder 6, the deck plate 3 and the like may be prepared in advance at a factory or the like and subjected to hot-dip galvanizing. it can. Therefore, it is possible to improve the safety of the work, reduce the work cost, shorten the work time, and the like. There is an advantage that the work period can be shortened by shortening the work time. For this reason, for example, in response to a request to replace a bridge whose service life has passed, construction can be completed in a very short time and at low cost, traffic obstacles can be minimized, and public Savings can be achieved.

  Further, the main girder 2 and the deck plate 3 are connected by a connecting means 4 using bolts and nuts, and the other horizontal girder 5 and the main girder 2, and the horizontal girder 5 and the vertical girder 6 are also connected by the connecting means 4. Even if it is necessary to replace specific components due to an accident or the like, the minimum required main girder 2, horizontal girder 5, vertical girder 6, deck plate 3, etc. are replaced. By doing so, there is an advantage that the original state can be completely restored in a short time and at low cost.

  On the other hand, the horizontal girder 5 connecting the adjacent main girders 2 is formed of a rolled H-section steel for a welding structure at predetermined intervals in the longitudinal direction of the main girders 2, and its upper flange Bu51 and deck plate 3 is connected by the connecting means 4, for example, the axle load of an automobile acts between the adjacent main girders 2 on the deck plate 3, whereby the deck plate 3 is placed between the adjacent main girders 2. Even when a bending moment acting to bend downward is applied, the bending moment can be held by the cross beam 5 and the deck plate 3 having large bending rigidity. Therefore, bending deformation of the deck plate 3 between the adjacent main girders 2 can be reduced as much as possible. Further, since the distribution cross beam 05 is formed of a material having a larger second moment of area in the vertical direction than the normal cross beam 5, the deck plate in the bridge axis orthogonal direction Y at the central portion in the longitudinal direction of the main girder 2 is provided. The bending deformation of No. 3 can be suppressed smaller.

  Further, since the web Bw53 of the cross beam 5 is connected to the gusset plate Ag24 welded to the main beam 2 by the connection means 4, the main beam 2 and the cross beam 5 can be integrally and firmly connected. Regarding the main girder 2 and the distribution girder 05, the distribution gusset plate Ag024 welded to the main girder 2 and the web Bw53 of the distribution girder 05 are connected by the connection means 4 via two attachment plates As025. Because of this, it is possible to more firmly and integrally connect. Moreover, since the gusset plate Ag24 and the web Bw53 of the cross beam 5 are in contact with each other, the contact portion of the distribution gusset plate Ag024 with the attachment plate As025, and the web Bw053 of the distribution cross beam 05 are connected. Fretting corrosion or the like does not occur in the contact portion with the plate As025.

  Further, since the vertical girders 6 are provided between the adjacent main girders 2, the bending rigidity of the deck plate between the adjacent main girders 2 can be further increased. Moreover, fretting corrosion or the like does not occur in portions that contact each other, such as the main girder 2, the horizontal girder 5, the vertical girder 6, and the deck plate 3.

  Further, since the entire surface of all the constituent members such as the main girder 2, the deck plate 3, the connecting means 4, the horizontal girder 5, and the vertical girder 6 is covered with the hot-dip galvanized layer, a steel floor with an extremely high rust prevention effect is provided. You can get a print bridge.

  Furthermore, a waterproof layer is provided so as to cover the entire surface of the upper flange Au21 at a higher position than the upper surface of the main girder 2, and an asphalt pavement layer is provided so as to overlap the waterproof layer. , Can be prevented from reaching the deck plate 3, the main girder 2, and the like. Therefore, the rust prevention effect on the upper surface side of the deck plate or the like can be particularly improved.

  Moreover, while the rigidity of the bridge can be increased by the main girder 2 and the like, the elasticity of the road surface can be improved by the asphalt pavement layer 81, so that both the stability and the riding comfort of the vehicle when passing through the bridge are improved. Can be improved. In addition, it is possible to reduce the impact and noise when the vehicle passes through the bridge. In addition, asphalt pavement requires an extremely short curing time as compared with concrete pavement, so that there is an advantage that the construction period can be shortened and traffic obstruction can be minimized.

  On the other hand, since the structure does not use concrete for improving the strength, there is no need to consider the curing time, and the construction period can be shortened accordingly. In addition, since the weight of the strength members can be reduced, it is not necessary to arrange large-scale heavy equipment, so that the construction period can be shortened and the total cost can be reduced.

  Further, since the deck plate 3 is not a stiffened plate formed by welding longitudinal ribs or the like, the cost required for welding or the like can be reduced, and the fatigue durability of the deck plate 3 can be improved. it can.

  In the above-described embodiment, an example in which six main girders 2 are provided is shown. However, the main girders 2 may be configured to have two or more main girders. In addition, as for the horizontal girder 5, an example is shown in which three main girder 2 are provided between both end portions in the longitudinal direction, but one or more other horizontal girder 5 is provided between both end portions. Is also good.

DESCRIPTION OF SYMBOLS 1 Steel deck bridge 2 Main girder 3 Deck plate 4 Connecting means 5 Horizontal girder 6 Vertical girder 21 Upper flange Au
22 Lower flange Ad
23 Web Aw
24 Gusset Plate Ag
024 Distribution gusset plate Ag
025 Attached plate As
51 Upper flange Bu
52 Lower flange Bd
53 Web Bw
54 Gusset Plate Bg
61 Upper flange Cu
62 Lower flange Cd
63 Web Cw
81 Asphalt pavement layer

Claims (7)

At least two iron main girders installed to extend in the longitudinal direction toward the bridge axis;
An iron deck plate placed so as to straddle the adjacent main girder,
An iron screw having a head at one end of the male screw portion and an iron nut screwed to the male screw portion, and are arranged between the head of the bolt and the nut and overlapped with each other. Connecting means for bringing a plurality of objects into a state of being pressed and connected together,
The main girder has an upper flange Au, a lower flange Ad located below the upper flange Au, and a web Aw orthogonal to the upper flange Au and the lower flange Ad. An upper surface is formed by an H-shaped steel frame arranged at a position corresponding to the lower surface of the deck plate,
In a portion where the deck plate and the upper flange Au overlap each other, a through-hole penetrating the overlapping portion is formed,
In the connecting means, a male screw part of the bolt is inserted into the through hole, and the nut is screwed into the male screw part protruding from the through hole,
Between the adjacent main girders, the adjacent main girders extend over the adjacent main girders at respective positions of both ends in the longitudinal direction of the main girder and at least one position between the both ends. There is an iron horizontal girder connected to the main girder,
The cross beam includes an upper flange Bu, a lower flange Bd positioned below the upper flange Bu, and a web Bw orthogonal to the upper flange Bu and the lower flange Bd. An upper surface is formed by an H-shaped steel frame arranged at a position corresponding to the lower surface of the deck plate,
An iron gusset plate Ag formed so as to partially overlap the web Bw is welded to the main girder at a position corresponding to the web Bw of each horizontal girder,
In a portion where the deck plate and the upper flange Bu overlap each other, a through hole penetrating the overlapping portion is formed, and also in a portion where the web Bw and the gusset plate Ag overlap each other, the overlapping portion is also defined. A through hole that penetrates is formed,
The connecting means is disposed at the position of each of the through holes, a male screw portion of each of the bolts is inserted into each of the through holes, and each of the nuts protrudes from each of the through holes. A steel slab bridge that is screwed. At least two iron main girders installed to extend in the longitudinal direction toward the bridge axis;
An iron deck plate placed so as to straddle the adjacent main girder,
An iron screw having a head at one end of the male screw portion and an iron nut screwed to the male screw portion, and are arranged between the head of the bolt and the nut and overlapped with each other. Connecting means for bringing a plurality of objects into a state of being pressed and connected together,
The main girder has an upper flange Au, a lower flange Ad located below the upper flange Au, and a web Aw orthogonal to the upper flange Au and the lower flange Ad. An upper surface is formed by an H-shaped steel frame arranged at a position corresponding to the lower surface of the deck plate,
In a portion where the deck plate and the upper flange Au overlap each other, a through-hole penetrating the overlapping portion is formed,
In the connecting means, a male screw part of the bolt is inserted into the through hole, and the nut is screwed into the male screw part protruding from the through hole,
Between the adjacent main girders, the adjacent main girders extend over the adjacent main girders at respective positions of both ends in the longitudinal direction of the main girder and at least one position between the both ends. There is an iron horizontal girder connected to the main girder,
The cross beam includes an upper flange Bu, a lower flange Bd positioned below the upper flange Bu, and a web Bw orthogonal to the upper flange Bu and the lower flange Bd. An upper surface is formed by an H-shaped steel frame arranged at a position corresponding to the lower surface of the deck plate,
The main girder is welded with an iron gusset plate Ag formed at a position corresponding to the web Bw of each horizontal girder so as to partially abut against an end surface of the web Bw. Has been
On the gusset plate Ag and the web Bw of the cross beam, an iron attachment plate As having a shape partially overlapping both the gusset plate Ag and the web Bw is superimposed on the gusset plate Ag and the web Bw,
In a portion where the deck plate and the upper flange Bu overlap each other, a through hole penetrating the overlapping portion is formed, and a portion where the gusset plate Ag and the attachment plate As overlap with each other and the web Bw are formed. A through-hole penetrating these overlapping portions is also formed in a portion where the supporting plate As overlaps with each other,
The connecting means is disposed at the position of each of the through holes, a male screw portion of each of the bolts is inserted into each of the through holes, and each of the nuts protrudes from each of the through holes. A steel slab bridge that is screwed. Between the adjacent main girder, there is provided an iron vertical girder extending over the adjacent horizontal girder and connected to the adjacent horizontal girder,
The stringer has an upper flange Cu, a lower flange Cd located below the upper flange Cu, and a web Cw orthogonal to the upper flange Cu and the lower flange Cd. An upper surface is formed by an H-shaped steel frame arranged at a position corresponding to the lower surface of the deck plate,
An iron gusset plate Bg formed so as to partially overlap the web Cw is welded to the cross beam at a position corresponding to the web Cw of each vertical beam,
In a portion where the deck plate and the upper flange Cu overlap each other, a through-hole penetrating the overlapping portion is formed, and also in a portion where the web Cw and the gusset plate Bg overlap each other, the overlapping portion is also defined. A through hole that penetrates is formed,
The connecting means is disposed at the position of each of the through holes, a male screw portion of each of the bolts is inserted into each of the through holes, and each of the nuts protrudes from each of the through holes. The steel slab bridge according to claim 1 or 2 , which is screwed. Between the adjacent main girder, there is provided an iron vertical girder extending over the adjacent horizontal girder and connected to the adjacent horizontal girder,
The stringer has an upper flange Cu, a lower flange Cd located below the upper flange Cu, and a web Cw orthogonal to the upper flange Cu and the lower flange Cd. An upper surface is formed by an H-shaped steel frame arranged at a position corresponding to the lower surface of the deck plate,
An gusset plate Bg made of iron is formed on the cross beam, at a position corresponding to the web Cw of each of the vertical beams, such that a part of the gusset plate Bg is formed so as to abut against an end surface of the web Cw. Has been
On the gusset plate Bg and the web Cw of the stringer, an iron attachment plate Bs partially overlapping both the gusset plate Bg and the web Cw is superimposed on the gusset plate Bg and the web Cw,
In a portion where the deck plate and the upper flange Cu overlap each other, a through-hole penetrating the overlapping portion is formed, and a portion where the gusset plate Bg and the attachment plate Bs overlap each other and the web Cw A through-hole penetrating these overlapping portions is also formed in a portion where the auxiliary plate Bs overlaps each other,
The connecting means is disposed at the position of each of the through holes, a male screw portion of each of the bolts is inserted into each of the through holes, and each of the nuts protrudes from each of the through holes. The steel slab bridge according to claim 1 or 2 , which is screwed. The main girder, the deck plate and the connecting means according to any one of claims 1 to 4 , the cross girder and the gusset plate Ag according to any one of claims 1 to 4 , and any of the claims 2 to 4 . The attachment plate As described in any one of claims 1 to 4 , the stringer and the gusset plate Bg according to any one of claims 3 to 4 , or the attachment plate Bs according to claim 4 are each provided with a hot-dip galvanized layer. A steel floor slab bridge, wherein the steel floor slab bridge is covered with one of a predetermined coating layer and a layer in which a predetermined coating layer is overlaid on a hot-dip galvanized layer. Claim 1, characterized in that the asphalt pavement layer is provided on the upper side of the main waterproof layer is provided so that the whole of the upper flange Au top higher than the site of the surface of the digit to cover at least the waterproof layer The steel floor slab bridge according to any one of claims 1 to 5 , wherein The steel floor slab bridge according to claim 6 , wherein the waterproof layer is configured by at least one of a waterproof coating and a waterproof sheet.

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