JP2011256712A - Pier part auxiliary support mechanism and construction method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pier part (bridge base part) auxiliary support mechanism for supporting a super structure auxiliarily beneath the super structure along with bearings so that when a bridge girder is slipped out of the bearings due to earthquakes and so forth, an impact load may not be applied to a bridge seat.SOLUTION: A pier part auxiliary support mechanism comprises a connecting body 40 extended on a bridge seat 2a of a bridge pier 2 in the bridge axial direction, and abutment bodies 41 that are arranged on both sides of the bridge axial direction of the bridge seat 2a by being fixed to both ends of the connected body 40 and that abut on the underside of a bridge girder 8 which is supported by bearings 2b.

Description

  The present invention relates to a technique for preventing a falling bridge that holds an upper structure such as a bridge girder or a floor slab from falling from a lower structure such as an abutment or a pier.

  As seen in the 1995 Hyogoken-Nanbu Earthquake, if a bridge such as a highway collapses due to an earthquake, it will cause enormous damage to the entire area. Therefore, the structure to prevent the falling of bridges has been reviewed, and measures to prevent the falling of bridges have been proposed, such as widening the girders (bridges) and connecting the upper structures (to be called units of bridge girders and floor slabs). .

  The prevention of falling bridges by widening the girders is a structure in which concrete is widened to the abutments and pier girder, or widened by attaching steel brackets with anchor bolts. In addition, to prevent falling bridges by connecting the upper structures, through holes are provided in the bridge width direction at the ends of the bridge girders and floor slabs, connecting the upper structures facing each other through wires, etc. For example, a structure shown in FIGS. 13 and 14 of Patent Document 1 (see paragraphs 0048 to 0052) is known.

JP-A-10-159021

  In the conventional bridge-falling prevention structure, in the case of the girder widening method, there is a bearing gap between the upper surface of the widened portion and the bridge girder, and when the bridge girder is removed from the bearing, the upper structure falls by that gap. It remains uncertain whether the impact load can be fully supported by the widened part. In addition, in the case of the superstructure connection method, the wire and chain are slackened so that an impact load is applied when the bridge girder is detached from the support, and it can withstand this. I am still worried about whether or not.

  The present invention has been proposed for the above-described problem, and a connecting body that is passed in the direction of the bridge axis on the girder of the bridge pier, and the bridge of the girder by being fixed to both ends of the connecting body. Provided is a bridge pier sub-support mechanism characterized by including an abutting body that is arranged on both sides in the axial direction and abuts against a lower surface of a bridge girder supported by a support.

  Moreover, as a construction method of this bridge pier sub-support mechanism, a step of passing an insertion pipe in the bridge axis direction on the bridge pier seat, and a step of temporarily attaching the contact body to both sides of the bridge shaft in the bridge axis direction; A step of inserting a connection body into the insertion pipe; and a step of fixing the contact body at both ends of the connection body so that the contact body contacts the lower surface of a bridge beam supported by a support; The construction method characterized by including is provided.

  According to the present invention, in addition to the support, a bridge pier sub-support mechanism that supports the upper structure in an auxiliary manner is provided below the upper structure, so that an impact load may be applied to the girder seat when the bridge girder is detached from the support. Is much lower than before.

Schematic showing the substructure and superstructure of the bridge. The principal part top view explaining the expansion joint of a falling bridge prevention apparatus. The figure explaining the construction procedure of the expansion joint of FIG. The figure explaining the expansion joint of FIG. The figure explaining the subsequent process of FIG. The figure which shows the example of the foam material used at the process of FIG. The figure explaining the subsequent process of FIG. The figure explaining the subsequent process of FIG. The figure explaining the subsequent process of FIG. FIG. 10 is a cross-sectional view of an essential part for explaining a construction state of the upper structure after FIG. 9 (cross-sectional line omitted). The figure which shows the example of the penetration rod body which uses a mechanical coupling. The figure seen from the bridge-axis direction of the ground cover part explaining the latching state of a through-bar body. The figure seen from the bridge width direction of the ground cover part explaining the latching state of a penetration rod body. The principal part sectional view explaining the pier part auxiliary support mechanism concerning the present invention. The figure which looked at the pier part auxiliary | assistant support mechanism of FIG. 14 from the bridge-axis direction. The principal part sectional drawing explaining the abutment part sub-support mechanism which concerns on another aspect. The figure explaining the auxiliary support mechanism installed in the lower side of an upper structure. The figure which looked at the auxiliary support mechanism of FIG. 17 from the bridge-axis direction. The figure explaining the auxiliary | assistant support mechanism spanned between the abutments. The figure which shows another form about the expansion joint of a falling bridge prevention apparatus. The figure which shows another form about the expansion joint of a falling bridge prevention apparatus. The figure which shows the example of the fallen bridge prevention apparatus in the case of a butt-type expansion joint.

  In any of the above-mentioned conventional anti-falling bridge structures, it is necessary to drill holes for anchors in the concrete of the lower and upper structures, but the position of the reinforcing bars inside the concrete of the bridge is uncertain. When a hole is opened, there is a possibility that the rebar will be reopened, or the rebar may be damaged without knowing with a core drill or the like to open the hole.

  Based on such a technical background, there is a need for a fall prevention device and a fall prevention method that can prevent a fall bridge more reliably without uncertain drilling of important parts such as piers, abutments and floor slabs. .

  Therefore, the falling bridge prevention device shown below is a finger joint type having a through-hole in the bridge width direction in the finger part, and is inserted into the through-hole in an expansion joint installed in the joint of the upper structure in a loosely inserted state. And a penetrating bar extending in the bridge width direction.

  In addition, the following method for preventing a falling bridge includes a step of putting a cushioning material between finger portions engaged with each other in a finger joint type expansion joint having a through hole in the bridge width direction as a finger portion, and a loose insertion state in the through hole. Place the expansion joint at the superstructure construction site while maintaining the gap between the fingers in the expansion joint after piping and the process of inserting the penetration pipe in the bridge width direction and the conditions of the construction site. And the step of fixing the anchor of the expansion joint to the floor slab, the step of placing concrete in the upper structure construction site, and the projecting sideways of the upper structure after passing the through-rod body through the through pipe And a step of locking both end portions of the penetrating bar.

  According to these falling bridge prevention devices and the falling bridge prevention method, the penetrating rods passed through the through holes of the finger portions engaged with each other prevent separation of the expansion joint installed at the joint of the upper structure, that is, between the finger portions. Since it plays the role of a connecting device that keeps it far from the maximum gap, if an unexpected force due to an earthquake or the like is applied, the external force is shared between the upper structures, and each other holds the other Can work like that. That is, the ability to prevent the falling bridge is improved by providing the expansion joint with a function of connecting the upper structures.

  In this way, by providing the expansion joint with a connecting function, there is no need for a slack as in the connection method between the upper structures using wires or chains, and even if one of the upper structures is removed from the support, The superstructure is supported by the connecting function of the expansion joint, so that the superstructure that is detached from the bearing can be prevented from dropping suddenly to the beam seat. Therefore, the possibility that an impact load is applied to the girders is much lower than in the past.

  In addition, in the case of a newly built bridge, a drop prevention device can be installed at the joint construction stage of the superstructure joint, and in the case of an existing bridge, the fall prevention device is incorporated in the joint replacement stage of the superstructure joint. be able to. Since it can be constructed by joint replacement work, there is no need to drill holes in piers, abutments, or floor slabs, and the worry of damaging reinforcing bars without knowing it is eliminated.

  FIG. 1 schematically shows an example (road bridge) of a bridge to which the present invention is applied.

  Supports 1b and 2b are installed on girders 1a and 2a of the abutment 1 and the pier 2 which are elements of the substructure, and a plurality of superstructures 3 are supported by the supports 1b and 2b. It is stretched over. And the expansion joint 10 is installed in the joint of these upper structures 3. FIG. The expansion joint 10 is a pair of finger joints that are formed by interlinking the fingers alternately between the roadbed R and the upper structure 3 on the abutment 1 and between the upper structures 3 on the pier 2. The type is used. The falling bridge prevention device is configured to include the expansion joint 10, and a schematic plan view of the details is shown in FIG. 2.

  The fallen bridge prevention device shown in the figure has through-holes 12 (in the bridge width direction) in the finger portions 11 that mesh with each other in finger joint type expansion joints 10 installed at the joints of the upper structure 3 (floor slab 4, end of roadbed R). 4) and the like, and a through rod body 13 is inserted into the through hole 12 in a loosely inserted state and passed in the bridge width direction. The penetrating bar body 13 has both end portions 14 formed in a bolt shape, and the both end portions 14 have a length protruding sideways from the ground cover 5 of the upper structure 3, and nuts 15 are screwed into the both end portions 14. Thus, it is locked to the side of the upper structure 3. The nut 15 is tightened with a resin plate 16 and a square washer 17 serving as packings interposed between the nut 15 and the ground cover 5.

  The construction method of such a fall-bridge prevention apparatus is demonstrated with reference to FIGS.

  First, as shown in FIG. 3, the expansion joint 10 welds a reinforcing bar anchor 19 to the back surface of a steel plate 18, and welds a steel material having a U-shaped cross section as a finger to the surface of the plate 18. By doing so, the finger part 11 is formed. An I-type steel material or an H-type steel material can be used for the plate 18, and a square pipe-type steel material, a C-type steel material, a groove-type steel material, or an L-type steel material can be used for each finger material.

  The expansion joint 10 is assembled by engaging the finger portions 11 formed in this way (FIG. 4). Then, since the finger portion 11 is hollow with a “U” cross section, a through hole 12 penetrating in the bridge width direction is formed in the series of finger portions 11. The expansion joint 10 assembled in this manner is turned upside down, and a cushioning material is inserted between the finger portions 11 engaged with each other.

  In the step of putting the cushioning material, first, the step of putting the cushioning material in the valley portion gap 20 between the finger portions 11 is carried out with the gap between the engaging finger portions 11 being set to the maximum free play state (FIG. 5). The maximum clearance is the joint interval at the lowest temperature assumed in the bridge installation environment, and is calculated in consideration of the size of the through hole 12. When putting the cushioning material, first, a resin sheet 21 having a thickness of 0.5 to 4.0 mm is laid on the bottom of the valley portion gap 20 of the expansion joint 10 that is turned upside down, and the sealing agent 22 is placed thereon. Pour to 10-30 mm thickness to cure. As the sealing agent 22, it is preferable to select a low-elasticity material that is sticky even after curing. In succession, the sealing agent 22 is formed, and then a foam material 23 such as a low elasticity sponge is filled. As shown in FIG. 6, it is preferable that the foam material 23 is formed with slits 24 by cutting or pasting a part thereof, which leads to stress relaxation when the gap becomes wider than expected. be able to.

  Thus, after putting the buffer material which consists of the resin sheet 21, the sealing agent 22, and the foaming material 23 in the trough part gap | interval 20, between the finger parts 11 of the said expansion joint 10 is made into the minimum gap state this time, the finger parts 11 A step of putting a cushioning material into the gap 20 '(finger side) of the remaining portion is performed (FIG. 7). The minimum clearance is the seam interval at the highest temperature assumed in the bridge installation environment. The buffer material process is also performed in the same manner as the process of FIG. 5, and a buffer material composed of the resin sheet 25, the sealing agent 26, and the foam material 27 is formed. Then, when the buffer material has been inserted, the through pipe 28 is inserted into the through hole 12 and piped in the bridge width direction in the loosely inserted state. The through pipe 28 is substantially equal to the length of the expansion joint 10 in the bridge width direction, that is, the bridge width from one ground cover 5 to the other ground cover 5.

  As a result, when the cushioning material enters the entire gap between the finger portions 11, the space between the finger portions 11 is set to the loose state in the case of the average temperature, and as shown in FIG. 8, the upper surface of the expansion joint 10 turned upside down. A rubber or soft plastic water-impervious sheet 29 is adhered to (that is, the lower surface at the time of installation) or fixed with a washer & screw 30 and covered.

  Next, the expansion joint 10 is returned to the top and bottom, and temporarily fixed by spot welding of the angle bar 31 or the like in a loose state in accordance with the temperature at the time of construction at the bridge installation site (FIG. 9). The length of the expansion joint 10 in the bridge width direction is set to the length between the outer surfaces of the ground cover 5 and is preferably waterproofed by a laterally tightened rubber packing. The joint is filled with a sealant. Preparation for construction is now complete.

  Using the expansion joint 10 after piping maintained between the finger portions 11 in a loose state matching the conditions of the construction site, the anchor 19 is placed on the floor slab 7 by welding, etc. A fixing step is performed (FIG. 10). The construction site of the superstructure 3 is a trace of removing the existing joint if the construction is to replace the joint of the existing bridge.

  Subsequently, concrete is placed on the construction site of the superstructure 3 in which the expansion joint 10 is disposed to finish the road surface level, and the ground cover 5 and the rail 6 are reproduced and cured. After curing, the penetrating rod body 13 is passed through the penetrating pipe 28, and both end portions 14 of the penetrating rod body 13 protruding to the side of the upper structure 3 are latched to prevent slippage.

  The penetrating bar 13 may be composed of a single steel bar or a bar having a high shearing force. However, in consideration of workability, a large number of short steel bars or high shearing bar 13a threaded at both ends are prepared, The method of inserting this into the penetration pipe 28, connecting with the mechanical coupling 13b, is more suitable (FIG. 11). The penetrating bar 13 has such a length that both end portions 14 project from the side surface (ground cover 5) of the upper structure 3, and a square resin packing 16 is attached to the projecting end portion 14 with a square washer 17 and a nut 15 (see FIG. 12 and FIG. 13). Adjust the torque so that the nut 15 is not tightened too tightly, and be careful not to disturb the change in play. In addition, in the case of a sloping bridge, the fit of the washer 17 and the nut 15 is adjusted by changing the shape of the packing 16 to a shape matching the angle. In addition, the ground cover joint is provided with a waterproof seal.

  In addition to the above-described fallen bridge prevention device / construction method using an expansion joint connection structure, a secondary support mechanism according to the present invention can be provided to support the upper structure 3 in an auxiliary manner below the upper structure 3. The embodiment is shown below.

  First, as shown in FIGS. 14 and 15, the pier sub-support mechanism provided for the pier 2 includes a connecting body 40 that extends in the direction of the bridge axis on the girder 2 a of the pier 2, and It is comprised including the contact body 41 which contact | abuts to the lower surface of the bridge girder 8 which is arrange | positioned at the both sides of the bridge axis direction of the girder 2a by being fixed to both ends, and is supported by the support 2b. The contact body 41 of the present embodiment has a lower extension 42 extending downward from the connecting body 40, and the lower extension 42 contacts the side surface of the pier 2. Thus, by having the downward extension part 42, the state which pinched | interposed and fixed the bridge pier 2 with the contact body 41 can be obtained, and the condition is good. Further, since the lower extension 42 is in contact with the pier 2, the load can be shared and supported from the lower extension 42 to the side surface of the pier 2 when receiving the load of the upper structure 3 removed from the support 2 b. The function of preventing the connecting body 40 from bending is also provided.

  The construction method of such a bridge pier sub-supporting mechanism is as follows. First, a contact body 41 having a rib having a contact with the bridge girder 8 and provided with a connection hole for allowing the connection body 40 to pass through is attached to the resin packing 43. And temporarily fastened to both sides of the bridge axis direction of the girders 2a. At this time, the resin packing 44 may be interposed between the contact body 41 and the lower surface of the bridge beam 8. And on the girder 2a, the insertion pipe 45 is handed over to the connection hole site | part of the contact body 41 temporarily fastened in the bridge axis direction. The insertion pipe 45 can be made of steel or plastic. Subsequently, a connecting body 40 made of steel or high-tensile material is inserted into the insertion pipe 45 through the connection hole of the contact body 41, and epoxy resin, polymer cement, or the like is inserted into the gap between the inserted connection body 40 and the insertion pipe 45. The filler is injected for rust prevention. And the both ends which the connection body 40 protruded are fixed with the washer 46 and the nut 47, contacting the contact body 41 via the resin packing 44 to the lower surface of the bridge girder 8 supported by the support 2b.

  Thereby, in addition to the connection function of the expansion joint 10, in addition to the support 2b, the upper structure 3 is supplementarily supported from below, and a pier sub-support mechanism and a construction method thereof are provided that prevent the falling bridge more reliably.

  It is possible to provide not only the pier part but also the abutment 1 with an abutment part auxiliary support mechanism that supports the upper structure 3 as a secondary. An example of this is shown in FIG.

  The abutment part auxiliary support mechanism provided for the abutment 2 is a cantilever 50 that is passed in the direction of the bridge axis on the beam 1a of the abutment 1 and penetrates the parapet 1c and is locked to the roadbed R side. And a contact body 51 that is fixed to the end portion of the holding body 50 so as to be disposed on the side of the bridge 1 in the bridge axial direction and that contacts the lower surface of the bridge 8 supported by the support 1b. Is done. The contact body 51 of the present embodiment has a lower extension 52 extending downward from the cantilever 50, and the lower extension 52 is in contact with the side surface of the abutment 1. The function of the lower extension 52 is the same as that of the lower extension 42 described above.

  In the construction method of such an abutment part sub-support mechanism, first, the insertion pipe 53 is passed in the bridge axis direction on the beam 1a and the parapet 1c is penetrated. At this time, the roadbed R on the opposite side of the parapet 1c holds a necessary portion. The insertion pipe 53 can be made of steel or plastic. And the contact body 51 which consists of a bracket which has the rib contact | abutted to the bridge girder 8 and provided the connection hole for letting the cantilever 50 pass through the bridge axial direction side of the girder 1a through the resin packing 54 Temporarily fasten. At this time, the resin packing 55 is interposed between the contact body 51 and the lower surface of the bridge beam 8. The contact body 51 is positioned so that the insertion pipe 53 and the connection hole communicate with each other. Subsequently, a steel or high-tensile material cantilever 50 is inserted into the insertion pipe 53 through the connection hole of the contact body 51, and an epoxy resin or polymer is inserted into the gap between the inserted cantilever 50 and the insertion pipe 53. Inject a filler such as cement for rust prevention. Then, the projecting end of the cantilever 50 is fixed with a washer 56 and a nut 57 while the abutment body 51 is brought into contact with the lower surface of the bridge girder 8 supported by the support 1 b via the resin packing 55. On the other hand, the other end of the cantilever 50, that is, the end protruding to the roadbed R side of the parapet 1c is engaged with the parapet 1c by a washer 58 and a nut 59.

  Thereby, in addition to the connection function of the expansion joint 10, in addition to the support 1b, the abutment part sub-support mechanism that supports the upper structure 3 from below and prevents the falling bridge more reliably and its construction method are provided. The closed roadbed R is reproduced after construction.

  In order to further improve the resistance against the falling bridge, it is possible to install a further auxiliary support mechanism below the upper structure 3. This is illustrated in FIGS.

  The auxiliary support mechanism of this example includes two or more high-tensile bars 60 installed between one abutment 1 and the other abutment 1 so as to crawl the lower side of the upper structure 3 in the direction of the bridge axis, and the upper structure. 3 and one or more crossing rods 61 spanned by the high-tension rod 60 so as to crawl the lower side in the bridge width direction. The high-strength rod 60 of this example is formed by adding a mechanical joint 62, and both ends of the high-strength rod 60 are fixed to the abutment 1 through the parapet 1 c, and are erected on both sides of the lower surface of each bridge girder 8. Has been. A large number of steel bar crossing bars 61 crossing on the high-tensile bar 60 are fixed by using an orthogonal clamp 63, and a cushioning material 64 such as a rubber plate is put in contact with the bridge girder 8. ing. The cross bar 61 may also be formed by adding a mechanical joint.

  In the construction method, first, high tension bars 60 are installed between the abutments 1 at a predetermined interval, and are placed under the upper structure 3 in the bridge axis direction, and the cross bars 61 are stretched around the high tension. A step of spanning the rod 60 in the bridge width direction is performed on the lower side of the upper structure 3 by being stopped by the crossing orthogonal clamp 63 over the rod 60.

  In this way, by extending the lattice-like auxiliary support mechanism under the upper structure 3, the upper structure 3 is supported from the bottom in addition to the connection function of the expansion joint 10. can do.

  In addition, in the construction method according to the present invention described above, the order of the respective steps can be changed, that is, the steps in the construction method of the present invention are not limited to the description order. It is preferable to carry out the process appropriately depending on the situation at the construction site.

  20 and 21 show an example of a falling bridge prevention device using an expansion joint having a different form from that of FIG.

  FIG. 20 shows an example of a finger joint type expansion joint 10 in which reinforcing ribs 70 are erected in the fingers. In this case, the through holes 12 in the bridge axis direction are formed through the ribs 70. . The through pipe 28 and the through rod body 13 are inserted into the through hole 12 in the bridge axis direction in a loosely inserted state. A buffer material 71 is inserted between the finger portions 11, and the lower surface is covered with a rubber sheet 72.

  FIG. 21 shows an example of a finger joint type expansion joint 10 formed by a deformed web 80 and concrete 81. In this case, the finger portion 11 penetrates the finger side wall of the web 80 and the concrete 81 inside the finger. Thus, the through hole 12 is formed in the bridge axis direction. The through pipe 28 and the through rod body 13 are inserted into the through hole 12 in the bridge axis direction in a loosely inserted state. A cushioning material 82 is similarly inserted between the finger portions 11.

  In FIG. 22, the example of the fallen bridge prevention apparatus in the case of the butt-type expansion joint 100 is shown. In the case of this expansion joint 100, a steel plate 102 is disposed opposite to the joint of the upper structure 3 with a waterproof material 101 interposed therebetween. Bolts 104 are loosely inserted in the direction of the bridge axis through the through-holes 103 of the plates 102 facing each other, and both ends of the bolts 104 are locked to the back surface of the plate 102 by washers and nuts 105, respectively. . In other words, the expansion joint 100 is connected by the bolt 104 and the nut 105 that are passed through the opposing plates 102, and is connected when the joint is going to spread beyond the maximum clearance. The falling bridge prevention device can also prevent the falling bridge by the action of the upper structures 3 as in the case of the finger joint type, and it is also possible to use the abutment part / abutment part auxiliary support mechanism and auxiliary support mechanism in combination. It is.

1 Abutment 1a Girder 1b Bearing 1c Parapet 2 Bridge pier 2a Girder 2b Bearing 3 Superstructure 4 Floor slab 5 Ground cover 6 Rail 7 Rebar (in the slab)
8 Bridge Girder 10 Expansion Joint 11 Finger Part 12 Through Hole 13 Through Bar Body 14 End (Through Bar Body)
15 Nut 16 Resin plate 17 Square washer 20 Valley part gap 20 'Gap 21, 25 other than valley part Resin sheet (buffer material)
22, 26 Sealing agent (buffer material)
23, 27 Foam (buffer material)
28 Through pipe 40 Connecting body 41 Abutting body 42 Lower extension parts 43, 44 Resin packing 45 Insertion pipe 46 Washer 47 Nut 50 Cantilever 51 Abutting body 52 Lower extension part 53 Insertion pipes 54, 55 Resin packing 56, 58 Washer 57, 59 nut

Claims (4)

A connecting body passed in the direction of the bridge axis on the girder of the pier;
An abutting body that is disposed on both sides of the bridge base in the bridge axis direction by being fixed to both ends of the coupling body, and abuts against the lower surface of the bridge girder supported by the support;
A pier sub-supporting mechanism characterized by comprising.   2. The pier sub-support mechanism according to claim 1, wherein the abutment body has a downward extension extending downward from the coupling body, and the downward extension abuts against a side surface of the pier. Passing the insertion pipe in the direction of the bridge axis on the girder of the pier;
Temporarily attaching the contact body to both sides of the bridge seat in the bridge axis direction;
Inserting a coupling body into the insertion pipe;
Fixing the abutting body at both ends of the connecting body so that the abutting body abuts on the lower surface of the bridge beam supported by the support;
The construction method of the pier sub-support mechanism characterized by including. In the step of inserting the connecting body into the insertion pipe,
The construction method according to claim 3, wherein a step of injecting a filler into a gap between the inserted coupling body and the insertion pipe is performed.

Images