Bridge-attached cable mounting structure

Abstract

To provide a fitting structure of a bridge-suspending cable which can be easily installed with a conventional simple structure.SOLUTION: In a cable 10 for a power or a communication, linked to a road bridge 2, an excess length part 11 bent like a lateral 8-shape in an end part of a first bridge girder 3. Upper end parts 11a and 11b of the excess length part 11 are supported by excess part holding members 12 and 12. Each excess part holding member 12 includes: a cylinder member 15 inserted into the cable 10; and a plurality of connection ropes 16 and 16 for coupling a part of the cylinder member 15 to a support member 14. An annular part 18a on a tip side of a release liner member 18 as a holding release mechanism is engaged to the connection ropes 16 and 16 of each excess part holding member 12, and the annular part on a base side is coupled to a lateral girder 20 on a second bridge girder 4 side. When displacement exceeding a reference value occurs between the first bridge girder 3 and the second bridge girder, a tension occurs in the release liner member 18 to cut each connection rope 16, and holding of the excess part 11 by each excess part holding member 12 is released.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mounting structure for a power or communication cable that is installed along a bridge. [Background technology]

[0002] Conventionally, there have been known mounting structures for power or communication cables that are strung along bridges, which are configured to reduce the effects of displacement of bridge components. One such cable mounting structure has been proposed in which the cable is bent in a mountain shape near the ends of two adjacent bridge girders to form excess lengths, and the bridge girder end side of each excess length is connected to an arm member extending from the opposing bridge girder end (see Patent Document 1).

[0003] In this bridge-attached cable mounting structure, the tips of two arm members are fitted so as to be guided by guide members provided on the opposing bridge girder ends. In addition, a displacement reduction device is installed near the tip of one of the arm members, which reduces the amount of displacement of the connecting part of the excess cable at the other bridge girder end to half the amount of displacement of the arm member.

[0004] When displacement occurs between adjacent bridge girders, the cable's connecting part to the arm member moves in the direction guided by the arm member, and the movement distance of the two connecting parts is equalized by the displacement reduction device, which is configured to stretch and contract the two excess cable parts evenly. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 02-250612 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional bridge-attached cable mounting structure includes an arm member, a connecting member that connects the cable to the arm member, a guide member that guides the arm member, and a displacement reduction device, which results in a relatively large number of parts and requires a lot of work to install. Furthermore, a relatively large space is required to install the arm member, guide member, and displacement reduction device, which makes it difficult to install depending on the bridge structure. Furthermore, the displacement reduction device includes mechanical elements such as a rack and pinion, which results in the disadvantages of requiring a lot of work to maintain and relatively low durability.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a bridge-attached cable mounting structure that has a relatively simple configuration, can be easily installed in a relatively narrow space, and has high durability. [Means for solving the problem]

[0008] In order to solve the above problems, the mounting structure for a bridge-attached cable of the present invention is a mounting structure for a communication or power cable that is laid between a first member and a second member of a bridge, an excess length portion provided in the vicinity of an end portion of the first member or the second member of the cable; an excess length holding member that holds an excess length of the cable at a holding position set in the first member or the second member; a retention release mechanism that releases retention of the excess length of the cable by the excess length retaining member when a relative displacement exceeding a reference value occurs between the first member and the second member, thereby allowing the excess length to be extended; It is characterized by having:

[0009] According to the above configuration, an excess portion is formed in a cable that is installed between a first member and a second member of a bridge, so as to be located near an end of the first member or the second member. Here, the excess portion may be formed in one of the first member and the second member, or may be formed in both the first member and the second member, and the number of excess portions is not particularly limited. The first member and the second member of the bridge are members that constitute the bridge and correspond to members that are subject to displacement between each other due to various causes such as earthquakes, vehicle loads, and wind loads. For example, the first member and the second member correspond to adjacent bridge girders. Also, for example, the first member and the second member correspond to adjacent bridge girders and abutments. The cable is a communication or power cable that is installed along the bridge, and corresponds to one that uses a conductor such as copper or aluminum, or one that uses optical fiber. The excess portion of the cable is held in a holding position set in the first member or the second member by an excess portion holding member. The holding position is set on the member on which the slack portion is formed. For example, if the slack portion is formed near the end of the first member, the holding position is set on the first member. Here, when a relative displacement exceeding a reference value occurs between the first member and the second member, the holding release mechanism releases the holding of the slack portion of the cable by the slack portion holding member. This allows the slack portion of the cable to extend. As a result, the cable can follow the relative displacement between the first member and the second member, reducing the impact on the cable and effectively preventing problems such as cable breakage or severance. The bridge-attached cable mounting structure configured as described above has a relatively simple configuration, consisting of an slack portion holding member that holds the slack portion and a holding release mechanism, and is therefore easy to install and can be installed in a relatively small space. Furthermore, since it does not include mechanical elements such as a rack and pinion, it requires little maintenance and has high durability.

[0010] In one embodiment, the bridge-attached cable mounting structure includes a linear member that connects the excess portion of the cable to the first member or the second member, The retention release mechanism includes a tensioning member to which a tensioning force is applied when a relative displacement exceeding a reference value occurs between the first member and the second member, and a cutting member that cuts the linear member of the excess portion retention member by the tensioning force of the tensioning member.

[0011] According to the above embodiment, the slack portion holding member includes a linear member, and the linear member connects the slack portion of the cable to the first member or the second member. The linear member may connect the slack portion of the cable to the first member or the second member directly or indirectly via another member. In addition, the hold-release mechanism includes a tensioning member and a cutting member, and when a relative displacement between the first member and the second member exceeds a reference value, a tensile force generated in the tensioning member causes the cutting member to cut the linear member of the slack portion holding member. When the linear member of the slack portion holding member is cut by the cutting member, the connection of the slack portion of the cable to the first member or the second member is released, and the slack portion becomes extendable. As a result, the cable can follow the relative displacement between the first member and the second member, preventing the cable from breaking or being cut.

[0012] In one embodiment, the bridge-attached cable mounting structure is configured such that the tension member of the retention release mechanism is formed of a linear member having a strength greater than that of the linear member of the excess portion retaining member, The cutting member of the holding release mechanism is provided at the tip of the linear member serving as the pulling member, and is formed by an annular portion that engages with the linear member of the excess portion holding member.

[0013] According to the above embodiment, the hold-release mechanism is formed by a linear member serving as a tensioning member and a ring-shaped portion provided at the tip of the linear member. When a relative displacement exceeding a reference value occurs between the first and second members of the bridge, a tension is generated in the linear member serving as a tensioning member, and a tensile force acts on the ring-shaped portion. Here, since the linear member serving as a tensioning member of the hold-release mechanism is stronger than the linear member of the slack-holding member, the linear member of the slack-holding member is cut by the ring-shaped portion. As a result, the hold of the slack portion of the cable by the slack-holding member is effectively released. Here, the ring-shaped portion serving as the cutting member of the hold-release mechanism may be formed by bending the tip of the linear member serving as a tensioning member into a ring shape and fixing it midway along the linear member. In other words, the tensioning member and cutting member of the hold-release mechanism may be integrally formed by the linear member.

[0014] In one embodiment of the bridge-attached cable mounting structure, the tension member of the retention release mechanism is formed of a linear member, The cutting member of the holding release mechanism is formed of a cutting blade that is driven by the tensile force of the linear member serving as the pulling member to cut the linear member of the excess portion holding member.

[0015] According to the above embodiment, the retention release mechanism includes a linear member serving as a tension member and a cutting blade driven by a tensile force acting on the linear member. When a relative displacement exceeding a reference value occurs between the first and second members of the bridge, the tension generated in the linear member serving as the tension member drives the cutting blade, which cuts the linear member of the slack portion holding member. As a result, the retention of the slack portion of the cable by the slack portion holding member is effectively released.

[0016] In one embodiment, the bridge-attached cable mounting structure includes an engaging fitting that engages with the first member or the second member, The retention release mechanism includes a tension member that applies a tensile force when a relative displacement occurs between the first member and the second member that exceeds a reference value, and this tensile force releases the engagement of the engaging fitting with the first member or the second member.

[0017] According to the above embodiment, the engaging fitting of the slack portion holding member engages with the first or second member to hold the slack portion of the cable at the holding position of the first or second member. Here, the engaging fitting may directly engage with the first or second member, or may indirectly engage via another member provided on the first or second member. The retention release mechanism includes a tension member, and a tensile force acts on the tension member of the retention release mechanism when a relative displacement between the first and second members exceeds a reference value. The tensile force of the tension member of the retention release mechanism releases the engagement of the engaging fitting with the first or second member. As a result, the retention of the slack portion of the cable by the slack portion holding member is effectively released.

[0018] In one embodiment, the bridge-attached cable mounting structure includes an excess length holding member that includes a magnet that attracts the excess length of the cable to the first member or the second member, The retention release mechanism includes a tensioning member that applies a tensioning force when a relative displacement occurs between the first member and the second member that exceeds a reference value, and this tensioning force releases the magnet from attraction to the first member or the second member.

[0019] According to the above embodiment, the magnet of the slack holding member is attracted to the first or second member, thereby holding the slack of the cable at the holding position of the first or second member. Here, the magnet may be attracted directly to the first or second member, or may be attracted indirectly to another member provided on the first or second member. The retention release mechanism includes a tension member, and a tension force acts on the tension member of the retention release mechanism when a relative displacement occurs between the first and second members that exceeds a reference value. The tension force of the tension member of the retention release mechanism releases the magnet from being attracted to the first or second member. As a result, the retention of the slack of the cable by the slack holding member is effectively released.

[0020] In one embodiment of the mounting structure for a bridge-attached cable, the tension member of the retention release mechanism is connected to a member of the first member and the second member that is different from the member in which the excess portion whose retention is released by the retention release mechanism is located.

[0021] According to the above embodiment, the tensioning member of the slack portion release mechanism disposed on one of the first and second members is connected to the other member, so that a tensioning force acts on the tensioning member when a relative displacement between the first and second members exceeds a reference value. Therefore, the retention release mechanism can reliably release the retention of the slack portion of the cable by the slack portion holding member.

[0022] In one embodiment of the bridge-attached cable mounting structure, the excess length of the cable at the holding position is bent in a mountain shape.

[0023] According to the above embodiment, the excess length portion of the cable is formed in a mountain shape, so that the excess length portion can be easily formed.

[0024] In one embodiment of the bridge-attached cable mounting structure, the excess length of the cable at the holding position is bent in an eight-shape.

[0025] According to the above embodiment, by making the shape of the excess cable an eight, twisting of the cable when this excess cable is extended can be prevented, thereby effectively preventing damage caused by twisting, such as breakage.

[0026] In one embodiment of the bridge-attached cable mounting structure, the excess length of the cable at the holding position is formed by two wound portions wound in opposite directions.

[0027] According to the above embodiment, the excess length of the cable is formed by two windings wound on opposite sides of the cable, thereby preventing twisting of the cable when the two excess lengths are extended. Therefore, damage caused by twisting, such as breakage, can be effectively prevented. Here, it is preferable that the windings of the cable are formed near the end of the first member and near the end of the second member. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram showing a bridge provided with a bridge-attached cable mounting structure according to a first embodiment of the present invention. [Figure 2] 3 is a side view showing a first excess length holding member in the bridge-attached cable mounting structure of the first embodiment. FIG. [Figure 3] 1 is a schematic diagram showing the bridge-attached cable mounting structure of the first embodiment when an earthquake occurs. FIG. [Figure 4A] 10 is a cross-sectional view showing an excess length holding member and a holding release mechanism in a bridge-attached cable mounting structure according to a second embodiment. FIG. [Figure 4B] 10 is a plan view showing an excess length holding member and a holding release mechanism in a bridge-attached cable mounting structure according to a second embodiment. FIG. [Figure 4C] 10 is a cross-sectional view showing the surplus length holding member and the holding release mechanism in the bridge-attached cable mounting structure of the second embodiment when an earthquake occurs. FIG. [Figure 5A] 10 is a plan view showing an excess length holding member and a holding release mechanism in a bridge-attached cable mounting structure according to a third embodiment. FIG. [Figure 5B] FIG. 10 is a side view showing an excess length holding member and a holding release mechanism in the bridge-attached cable mounting structure of the third embodiment. [Figure 5C] FIG. 10 is a plan view showing the slack portion holding member and the holding release mechanism in the bridge-attached cable mounting structure of the third embodiment when an earthquake occurs. [Figure 6A] FIG. 10 is a side view showing an excess length holding member and a holding release mechanism in the bridge-attached cable mounting structure of the fourth embodiment. [Figure 6B] FIG. 10 is a side view showing the slack portion holding member and the holding release mechanism in the bridge-attached cable mounting structure of the fourth embodiment when an earthquake occurs. [Figure 7A] FIG. 10 is a side view showing an excess length holding member and a holding release mechanism in the bridge-attached cable mounting structure of the fifth embodiment. [Figure 7B] FIG. 10 is a side view showing the surplus length holding member and the holding release mechanism in the bridge-attached cable mounting structure of the fifth embodiment when an earthquake occurs. [Figure 8]FIG. 10 is a schematic diagram showing a bridge provided with a bridge-attached cable mounting structure according to a sixth embodiment. [Figure 9] FIG. 13 is a schematic diagram showing a bridge provided with a bridge-attached cable mounting structure according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in detail below with reference to the illustrated embodiments.

[0030] Figure 1 is a schematic diagram showing a portion of a bridge on which a bridge-attached cable mounting structure according to a first embodiment of the present invention is provided. This bridge-attached cable mounting structure 1 is installed between a first bridge girder 3 as a first member and a second bridge girder 4 as a second member of a road bridge 2 serving as a bridge. This road bridge 2 is a girder bridge, and adjacent ends of the first bridge girder 3 and the second bridge girder 4 are supported by bearings 6 and 7 installed at the top ends of piers 5.

[0031] A power or communication cable 10 is supported by cable racks 8, 9 installed on bridge girders 3, 4 and is attached to the superstructure of a road bridge 2. The material of the cable 10 is not particularly limited as long as it is a cable used for power or communication purposes. The cable 10 may be, for example, one that uses a conductor such as copper or aluminum, or one that uses optical fiber. Furthermore, there is no limit to the number of conductors or optical fibers housed in the cable 10. The bridge-attached cable mounting structure 1 of this embodiment is installed to follow the displacement of the first bridge girder 3 and the second bridge girder 4 while preventing the cable 10 from breaking when displacement occurs between the first bridge girder 3 and the second bridge girder 4.

[0032] The bridge-attached cable mounting structure 1 of the first embodiment is configured to include an excess cable portion 11 provided at the end of a first bridge girder 3, two excess portion holding members 12, 12 that hold this excess cable portion 11 in a holding position set at the end of the first bridge girder 3, and two releasing linear members 18, 18 that function as a retention release mechanism that releases the retention of the excess cable portion 11 by the excess portion holding members 12, 12. The excess cable portion 11 is formed by bending the cable 10 sideways into a figure-eight shape.

[0033] The excess length 11 of the cable in this bridge-attached cable mounting structure 1 is set to a length greater than the maximum possible displacement between the first bridge girder 3 and the second bridge girder 4 when extended. In other words, compared to when the cable 10 is arranged linearly between the first bridge girder 3 and the second bridge girder 4, the excess length 11 is set to a length equivalent to the maximum possible displacement between the first bridge girder 3 and the second bridge girder 4 during an earthquake, for example, plus a surplus length. The lower end of this excess length 11 is placed on the cable rack 8, and the two upper ends 11a, 11b of the horizontal figure-eight shape are supported by two excess length holding members 12, 12, respectively.

[0034] FIG. 2 is an enlarged schematic diagram of the slack portion holding member 12 supporting one upper end 11a of the slack portion 11. The slack portion holding member 12 is connected to a rod-shaped metal support member 14 fixed to the first bridge girder 3. The shape and material of the support member 14 are not particularly limited as long as the slack portion holding member 12 can be connected to support the slack portion 11. The slack portion holding member 12 includes a flexible tubular member 15 through which the cable 10 is inserted, and connecting cords 16, 16 as multiple linear members that are wound around and connect the covered portion of the cable 10 covered by the tubular member 15 to the support member 14. The tubular member 15 can be formed, for example, from a corrugated rigid polyethylene pipe. The connecting cords 16 can be formed, for example, from a braided cord made of vinylon.

[0035] As shown in FIG. 2 , the distal end of a releasing linear member 18 is engaged with a plurality of connecting cords 16, 16 of the slack portion holding member 12. The releasing linear member 18 is made of, for example, stainless steel wire, and has loops formed at both ends by eyelets. A loop portion 18a at the distal end of the releasing linear member 18 is engaged in a chain-like manner with the plurality of connecting cords 16, 16 of the slack portion holding member 12. The proximal end of the releasing linear member 18 is connected to the second bridge girder 4, which is a member different from the member on which the slack portion 11 is installed. The proximal end of the releasing linear member 18 is connected by engaging the loop portion with a connecting hole provided in a cross beam 20 on the second bridge girder 4 side. The releasing linear member 18 has higher strength than the connecting cords 16 of the slack portion holding member 12. As a result, the annular portion 18a at the tip end of the releasing linear member 18 functions as a cutting member of the hold-release mechanism, and other portions of the releasing linear member 18 function as tension members of the hold-release mechanism. The excess length holding member 12 supporting the other upper end 11b of the excess length portion 11 also has a configuration similar to the excess length holding member 12 supporting one upper end 11a of the excess length portion 11. The releasing linear member 18 is normally flexible and generates substantially no tension, but is set to a length that becomes taut and generates tension when the distance between the first bridge girder 3 and the second bridge girder 4 reaches a reference value. The reference value for the distance between the first bridge girder 3 and the second bridge girder 4 is a value smaller than the maximum possible displacement between the first bridge girder 3 and the second bridge girder 4.

[0036] The bridge-attached cable mounting structure 1 configured as described above operates as follows. First, when a live load from a vehicle acts on the road bridge 2, when a wind load acts on the road bridge 2, or when a temperature change occurs, a displacement of several millimeters to several centimeters occurs between the first bridge girder 3 and the second bridge girder 4. This displacement is smaller than the reference value, and no tension is generated in the release linear member 18. Therefore, the upper ends 11a and 11b of the slack portion 11 of the cable are held by the slack portion holding members 12, 12, and the cable is held in an eight-shaped configuration. In this state, when a displacement of several millimeters to several centimeters occurs between the first bridge girder 3 and the second bridge girder 4, the cable 10 slides within the tubular members 15 of the slack portion holding members 12, 12, and the cable slack portion 11 expands or contracts while maintaining the eight-shaped configuration. In this way, the bridge-attached cable mounting structure 1 eliminates the influence on the cable 10 that is caused by slight displacement between the first bridge girder 3 and the second bridge girder 4.

[0037] On the other hand, if an earthquake or other event causes displacement between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 that exceeds a reference value, the release linear member 18 becomes taut and generates tension. This tension cuts the connecting cords 16 of the slack portion holding members 12, 12 that are engaged with the annular portions 18a, 18a at the tip ends of the two release linear members 18, 18, and the connection between the upper ends 11a, 11b of the slack portion and the support member 14 is released. In this way, the retention of the slack portion 11 by the slack portion holding members 12, 12 is released. As a result, the slack portion 11 of the cable becomes extensible, and as shown in Figure 3, the figure-eight-shaped portion of the slack portion 11 contracts and extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. The figure-eight shape of the slack portion 11 is eliminated depending on the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Thus, according to the bridge-attached cable mounting structure 1 of this embodiment, even if a large displacement occurs between the bridge girders 3 and 4 due to an earthquake or the like, inconveniences such as breakage of the cable 10 can be effectively prevented, and high earthquake resistance can be achieved.

[0038] FIG. 4A is a cross-sectional view showing the slack portion holding member and the retention release mechanism provided in the bridge-attached cable mounting structure of the second embodiment of the present invention, FIG. 4B is a plan view of the slack portion holding member and the retention release mechanism, and FIG. 4C is a cross-sectional view showing the slack portion holding member and the retention release mechanism when an earthquake occurs. FIG. 4A is a cross-sectional view taken along line A-A' in FIG. 4B. The bridge-attached cable mounting structure of the second embodiment has the same configuration as the bridge-attached cable mounting structure 1 of the first embodiment, except for the retention release mechanism. In the second embodiment, parts that perform the same functions as in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0039] Similar to the first embodiment, the slack holding member 12 included in the bridge-attached cable mounting structure of the second embodiment includes a tubular member 15 attached to upper ends 11a, 11b of the slack portion 11 of the cable and a tether 16 connecting the portion of the cable 10 covered by the tubular member 15 to a support member 14. The slack holding member 12 is provided with a tether-cord cutting device 23. The tether-cord cutting device 23 includes a casing 24 having an arc-shaped recess in contact with the outer surface of the tubular member 15, a sliding plate 25 that slides along the inner surface of the casing 24, a locking member 26 attached to the outer surface of the sliding plate 25, and a cutting blade 27 attached to the inner surface of the sliding plate 25. The casing 24 has tether-cord insertion holes 28 on its upper and lower surfaces in FIG. 4A for inserting the tether 16 therethrough. 4A, the casing 24 is provided with openings for inserting the annular portion 18a of the releasing linear member 18. The casing 24 is attached so that the recessed portion contacts the outer surface of the tubular member 15, and the tethering cord cutting device 23 is connected to the support member 14 together with the upper ends 11a, 11b of the cable slack portion 11 by the tethering cord 16 inserted through the tethering cord insertion hole 28. The releasing linear member 18 is attached so that the annular portion 18a of the releasing linear member 18 engages with the locking device 26 and encloses the outer surface of the slide plate 25, and is inserted through the opening of the casing 24 to enclose the tethering cord 16. The tethering cord cutting device 23 and the releasing linear member 18 constitute a hold release mechanism.

[0040] In the bridge-attached cable mounting structure of the second embodiment, in which the retention / release mechanism described above is installed, when displacement greater than a reference value occurs between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 due to an earthquake or the like, the release linear member 18 is tensed, generating tension. This tension drives the slide plate 25 of the tethering cord cutting device 23, which is contained in the annular portion 18a at the tip end of the release linear member 18, toward the back of the casing 24, as shown by arrow B in FIG. 4C . As a result, the cutting blade 27 on the inner surface of the slide plate 25 is pressed against the tethering cord 16 inserted into the casing 24, cutting the tethering cord 16 and releasing the connection between the upper ends 11a and 11b of the slack portion 11 of the cable and the support member 14. This releases the retention of the slack portion 11 by the slack portion retaining member 12, and the slack portion 11 extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Thus, according to the bridge-attached cable mounting structure of the second embodiment, even if an earthquake causes excessive displacement between the first bridge girder 3 and the second bridge girder 4, breakage or damage to the cable 10 can be effectively prevented.

[0041] Fig. 5A is a plan view showing the excess length holding member and retention release mechanism provided in a bridge-attached cable mounting structure of a third embodiment of the present invention, Fig. 5B is a side view of the excess length holding member and retention release mechanism, and Fig. 5C is a plan view showing the excess length holding member and retention release mechanism in the event of an earthquake. The bridge-attached cable mounting structure of the third embodiment has the same configuration as the bridge-attached cable mounting structure 1 of the first embodiment, except for the retention release mechanism. In the third embodiment, parts that perform the same functions as in the first embodiment are designated by the same reference numerals, and detailed explanations thereof will be omitted.

[0042] The slack holding member 12 included in the bridge-attached cable mounting structure of the third embodiment, like the first embodiment, includes a tubular member 15 attached to the upper ends 11a and 11b of the slack portion 11 of the cable and a connecting cord 16 connecting the portion of the cable 10 covered by the tubular member 15 to the support member 14. The slack holding member 12 is provided with a connecting cord cutter 33 as shown in FIG. 5A . The connecting cord cutter 33 includes a plate-like body 34 that is roughly rectangular in plan view and has a cutout that expands toward the back, and a cutting blade 35 provided at the back of the cutout of the plate-like body 34. The cutout of the plate-like body 34 is roughly rectangular in plan view, and is configured so that multiple connecting cords 16, 16, ... can be inserted into the cutout through openings formed on the long sides of the plate-like body 34, and the connecting cord cutter 33 is fixed against the side surface of the tubular member 15. A cutting blade 35 is fixed to the short side of a rectangular cutout provided in the plate-like body 34, with its cutting edge facing inside the cutout. The cutting edge of the cutting blade 35 is U-shaped so that it cuts the connecting cord 16 when the connecting cord 16, which is wound around the long side of the cutout, moves relatively toward the short side as the plate-like body 34 moves. A connection hole 36 is formed in the connecting cord cutter 33 on the side of the plate-like body 34 opposite to the side where the cutting blade 35 is provided, and the annular portion 18a at the tip of the releasing linear member 18 is inserted into this connection hole 36 to connect the releasing linear member 18. The connecting cord cutter 33 and the releasing linear member 18 constitute a hold release mechanism.

[0043] In the bridge-attached cable mounting structure of the third embodiment, in which the retention and release mechanism having the above-described configuration is installed, when a displacement greater than a reference value occurs between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 due to an earthquake or the like, the release linear member 18 becomes tense, generating tension. This tension pulls the tethering cord cutter 33 connected to the tip of the release linear member 18 toward the connection hole 36 of the plate-like body 34. As a result, the tethering cord 16 moves relatively within the notch of the plate-like body 34 toward the cutting blade 35, and as shown in FIG. 5C , the tethering cord 16 is cut by the cutting blade 35, releasing the connection between the upper ends 11a and 11b of the slack portion 11 of the cable and the support member 14. As a result, the retention of the slack portion 11 by the slack portion holding member 12 is released, and the slack portion 11 extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Thus, according to the bridge-attached cable mounting structure of the third embodiment, even if an earthquake causes excessive displacement between the first bridge girder 3 and the second bridge girder 4, breakage or damage to the cable 10 can be effectively prevented.

[0044] Fig. 6A is a side view showing the slack portion holding member and the retention release mechanism provided in the bridge-attached cable mounting structure of the fourth embodiment of the present invention, and Fig. 6B is a side view showing the slack portion holding member and the retention release mechanism in the event of an earthquake. The bridge-attached cable mounting structure of the fourth embodiment has the same configuration as the bridge-attached cable mounting structure 1 of the first embodiment, except for the slack portion holding member and the retention release mechanism. In the fourth embodiment, parts that perform the same functions as in the first embodiment are designated by the same reference numerals, and detailed explanations thereof will be omitted.

[0045] The slack portion holding member 42 provided in the bridge-attached cable mounting structure of the fourth embodiment is connected to a support member 45 provided on the superstructure of a road bridge 2. The support member 45 is fixed to the underside of a deck slab 44 supported by a first bridge girder 3. The slack portion holding member 42 of the fourth embodiment has an engaging fitting 46 that detachably engages with the support member 45, a tubular member 15 provided on upper ends 11a, 11b of the cable slack portion 11, and a connecting cord 16 that connects the covered portion of the cable 10 where the tubular member 15 is located to the engaging fitting 46.

[0046] 6A, the engaging fitting 46 has a fitting body 47 formed in a generally U-shape in side view, an engaging claw 48 and an engaging screw 49 arranged so as to face each other at the tip of the U-shaped fitting body 47, and a connecting cord attachment ring 50 connected to the fitting body 47. The support member 45 has an L-shaped cross section, and the upper end of the vertical part of the support member 45 is fixed to the deck slab 44, and the engaging fitting 46 is engaged with the horizontal part of the support member 45. The engaging fitting 46 is fixed to the support member 45 by inserting the tip of the U-shaped fitting body 47 into the horizontal part of the support member 45, threading the engaging screw 49 toward the engaging claw 48, and clamping the horizontal part of the support member 45 between the engaging screw 49 and the engaging claw 48. A connecting string 16 that wraps around the portion of cable 10 where tubular member 15 is covered is inserted into a knot attachment loop 50 located below an engaging fitting 46 fixed to support member 45, thereby holding upper ends 11a, 11b of excess cable portion 11. A tip of a releasing linear member 18 that serves as a holding release mechanism is connected to the engaging fitting 46. More specifically, an annular portion 18a at the tip of releasing linear member 18 is inserted into a U-shaped fitting body 47, and releasing linear member 18 is connected.

[0047] In the bridge-attached cable mounting structure of the fourth embodiment, which is equipped with the slack portion holding member 42 and the holding release mechanism configured as described above, when a displacement greater than a reference value occurs between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 due to an earthquake or the like, the release linear member 18 becomes tense, generating tension. This tension pulls the fitting body 47 of the engaging fitting 46, disengaging the engaging screw 49 and the engaging claw 48 from the support member 45, and the engaging fitting 46 disengages from the support member 45 as shown in FIG. 6B . This releases the holding of the slack portion 11 by the slack portion holding member 42, and the slack portion 11 extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Thus, the bridge-attached cable mounting structure of the fourth embodiment effectively prevents cable 10 from breaking or being damaged, even when excessive displacement occurs between the first bridge girder 3 and the second bridge girder 4 due to an earthquake.

[0048] Fig. 7A is a side view showing the slack portion holding member and the retention release mechanism provided in the bridge-attached cable mounting structure of the fifth embodiment of the present invention, and Fig. 7B is a side view showing the slack portion holding member and the retention release mechanism in the event of an earthquake. The bridge-attached cable mounting structure of the fifth embodiment has the same configuration as the bridge-attached cable mounting structure 1 of the first embodiment, except for the slack portion holding member and the retention release mechanism. In the fifth embodiment, parts that perform the same functions as in the first embodiment are designated by the same reference numerals, and detailed explanations thereof will be omitted.

[0049] The slack portion holding member 52 provided in the bridge-attached cable mounting structure of the fifth embodiment is fixed to the underside of the deck slab 44 that constitutes the superstructure of the road bridge 2. The deck slab 44 is supported by the first bridge girder 3. The slack portion holding member 52 of the fifth embodiment has an attraction portion 53 that is detachably attracted to the deck slab 44 by magnetic force, tubular members 15 provided on the upper ends 11a, 11b of the slack portion 11 of the cable, and a connecting cord 16 that connects the portion of the cable 10 where the tubular member 15 is covered to the attraction portion 53.

[0050] The attraction portion 53 is formed using a permanent magnet such as a neodymium magnet, and has a magnetic force that is sufficient to hold the excess cable portion 11 even in the event of an earthquake. A connection ring 54 is attached to the opposite side of the attraction surface of the attraction portion 53, and a connecting string 16 that wraps around the portion of the cable 10 where the tubular member 15 is covered is inserted into and fixed to this connection ring 54. In addition, the annular portion 18a at the tip of a release linear member 18 serving as a hold release mechanism is inserted into the connection ring 54, and the release linear member 18 is connected to it.

[0051] In the bridge-attached cable mounting structure of the fifth embodiment, in which the slack portion holding member 52 and the holding release mechanism configured as described above are installed, when a displacement equal to or greater than a reference value occurs between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 due to an earthquake or the like, the release linear member 18 becomes tense, generating tension. This tension pulls the suction portion 53, releasing the suction of the suction portion 53 to the deck slab 44 and causing the suction portion 53 to detach from the deck slab 44. This releases the retention of the slack portion 11 by the slack portion holding member 52, and the slack portion 11 extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Thus, the bridge-attached cable mounting structure of the fifth embodiment can effectively prevent cable 10 from breaking or being damaged, even if excessive displacement occurs between the first bridge girder 3 and the second bridge girder 4 due to an earthquake.

[0052] 8 is a schematic diagram showing a road bridge 2 provided with a mounting structure 101 for a bridge-attached cable of the sixth embodiment. The mounting structure 101 for a bridge-attached cable of this embodiment has the same configuration as the mounting structure 1 for a bridge-attached cable of the first embodiment, except for the shape and arrangement position of the excess cable length 111. In the sixth embodiment, parts that perform the same functions as in the first embodiment are denoted by the same reference numerals, and detailed explanations thereof will be omitted.

[0053] In the bridge-attached cable mounting structure 101 of the sixth embodiment, the cable slack portion 111 is formed to include two winding portions 112, 113 formed at the end of the first bridge girder 3 and the end of the second bridge girder 4, respectively. These two winding portions 112, 113 are formed by winding the cable 10 in opposite directions. Specifically, the winding portion 112 at the end of the first bridge girder 3 is wound from the front side to the back side of the paper as it moves from the left to the right side of FIG. 8. In contrast, the winding portion 113 at the end of the second bridge girder 4 is wound from the back side to the front side of the paper as it moves from the left to the right side of FIG. 8. The upper ends 112a, 113a of these winding portions are supported by slack portion holding members 12, 12, respectively.

[0054] In the bridge-attached cable mounting structure 101 of the sixth embodiment, the base ends of two releasing linear members 18, 18 that function as retention and release mechanisms for the slack holding members 12, 12 are connected to bridge girders 4, 3 that are different from the bridge girders 3, 4 on which the wound portions 112, 113 are installed. More specifically, the slack holding member 12 that holds the wound portion 112 arranged at the end of the first bridge girder 3 has the annular portion 18a on the tip side of the releasing linear member 18 engaged with the connecting cord 16, and the base end of this releasing linear member 18 is connected to the cross girder 20B on the side of the second bridge girder 4. On the other hand, the slack holding member 12 that holds the wound portion 113 arranged at the end of the second bridge girder 4 has the annular portion 18a on the tip side of the releasing linear member 18 engaged with the connecting cord 16, and the base end of this releasing linear member 18 is connected to the cross girder 20A on the side of the first bridge girder 3.

[0055] In the bridge-attached cable mounting structure 101 configured as described above, when a displacement greater than or equal to a reference value occurs between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 due to an earthquake or the like, the release linear members 18, 18 connected to each bridge girder 3, 4 are tensed, generating tension. This tension cuts the connecting cords 16, 16 of the slack portion holding members 12, 12 engaged with the annular portions 18a, 18a at the tips of the two release linear members 18, 18, releasing the connection between the upper ends 112a, 113a of the slack portion and the support member 14. In this way, the retention of the wound portions 112, 113 of the slack portion 111 by the slack portion holding members 12, 12 is released. As a result, the slack portion 111 of the cable is unwound from the two wound portions 112, 113 and extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Here, the two winding portions 112, 113 are wound on opposite sides to each other, so when they are unwound, the twists in the winding portions 112, 113 are released from each other, allowing the cable 10 to extend without twisting. Thus, with the bridge-attached cable mounting structure 101 of this embodiment, even if a large displacement occurs between the bridge girders 3, 4 due to an earthquake or the like, problems such as twisting or breakage in the cable 10 can be effectively prevented, and high earthquake resistance can be achieved.

[0056] 9 is a schematic diagram showing a road bridge 2 provided with a mounting structure 121 for a bridge-attached cable of the seventh embodiment. The mounting structure 121 for a bridge-attached cable of this embodiment has the same configuration as the mounting structure 1 for a bridge-attached cable of the first embodiment, except for the shape of the excess cable length 131. In the seventh embodiment, parts that perform the same functions as in the first embodiment are denoted by the same reference numerals, and detailed explanations thereof will be omitted.

[0057] In the bridge-attached cable mounting structure 121 of the seventh embodiment, an excess length portion 131 formed by bending the cable 10 into a mountain shape is provided at the end of the first bridge 3. An upper end portion 131a of this mountain-shaped excess length portion 131 is supported on a support member 14 of the first bridge 3 by an excess length holding member 12.

[0058] In the bridge-attached cable mounting structure 121 configured as described above, when a displacement equal to or greater than a reference value occurs between the first bridge girder 3 and the second bridge girder 4 of the road bridge 2 due to an earthquake or the like, the release linear members 18 connected to each of the bridge girders 3, 4 become tensed, generating tension. This tension cuts the connecting cords 16, 16 of the slack portion holding member 12 engaged with the annular portion 18a at the tip side of the release linear member 18, releasing the connection between the upper end 131a of the slack portion and the support member 14. In this way, the retention of the slack portion 131 by the slack portion holding member 12 is released. As a result, the slack portion 131 of the cable extends in response to the displacement occurring between the first bridge girder 3 and the second bridge girder 4. Thus, according to the bridge-attached cable mounting structure 121 of this embodiment, even if a large displacement occurs between the bridge girders 3 and 4 due to an earthquake or the like, problems such as twisting or breakage of the cable 10 can be effectively prevented, and high earthquake resistance can be achieved.

[0059] Although the bridge-attached cable mounting structures 1, 101, 121 of the first, sixth, and seventh embodiments support the slack 11, 111, 131 of the cable with the slack holding member 12 including the tether 16 and release the holding function of the slack holding member 12 with a holding release mechanism using the releasing linear member 18, other slack holding members or holding release mechanisms may be provided. For example, the bridge-attached cable mounting structures 1, 101, 121 of the first, sixth, and seventh embodiments may be provided with a holding release mechanism using the tether cutter 23 of the second embodiment, a holding release mechanism using the tether cutter 33 of the third embodiment, a slack holding member 42 using the engaging fitting 46 of the fourth embodiment, or a slack holding member 52 using the suction portion 53 of the fifth embodiment.

[0060] Furthermore, in the bridge-attached cable mounting structures 1, 101, 121 of the above-described embodiments, a vinylon connecting cord 16 is used as the linear member of the slack holding member, and a stainless steel wire releasing linear member 18 is used as the linear member forming the pulling member and cutting member of the hold-release mechanism, but the linear members of the slack holding member and the hold-release mechanism are not limited to these materials. As long as the linear member of the hold-release mechanism has a higher strength than the linear member of the slack holding member, the material is not particularly limited.

[0061] Furthermore, in each of the above embodiments, the reference value of the displacement between the first bridge girder 3 and the second bridge girder 4 at which the retention release mechanism is activated can be set appropriately depending on the situation that may occur between the first bridge girder 3 and the second bridge girder 4. For example, the reference value can be set to the maximum displacement that the first bridge girder 3 and the second bridge girder 4 can assume when they are supported by the piers 5. Furthermore, an earthquake support mechanism may be provided to support the first bridge girder 3 and / or the second bridge girder 4 that have detached from the piers 5 during an earthquake, and the displacement that occurs between the first bridge girder 3 and the second bridge girder 4 supported by this earthquake support mechanism may be set as the reference value.

[0062] Furthermore, in the first to seventh embodiments, the bridge-attached cable mounting structures 1, 101, 121 are installed between the first bridge girder 3 as the first member and the second bridge girder 4 as the second member, but the first and second members are not limited to bridge girders. For example, the present invention can be widely applied to any bridge between members that may be displaced and that constitute a bridge, such as using a bridge girder and an abutment as the first and second members.

[0063] Furthermore, in the above-described embodiments, the mounting structure for a bridge-attached cable of the present invention has been illustrated as being applied to a road bridge 2 having bridge girders 3 and 4, but the present invention can be applied to bridges having various bridge girders such as I-girders and box girders, and the bridge structure is not limited. Furthermore, the use of bridges is not limited to roads, and the mounting structure for a bridge-attached cable of the present invention can be applied to bridges for various uses such as railways, water, gas, and electricity.

[0064] The present invention is not limited to the above-described embodiments, and many modifications can be made by a person having ordinary skill in the art within the technical concept of the present invention. [Explanation of symbols]

[0065] 1,101,121 Bridge-attached cable mounting structure 2 Road bridges 3 First bridge girder 4 Second bridge girder 6,7 Bearing 8,9 Cable rack 10 Cable 11,111,131 Excess cable length 11a, 11b, 131a Upper end of excess length 12, 42, 52 Excess length retaining member 14,45 Support member 15 Cylindrical member 16 Connecting Cord 18 Releasing linear member 18a Annular portion of the release linear member 20,20A,20B Cross beam 23 Connecting cord cutting device 27,35 cutting blade 33 Connecting cord cutter 44 Floor slab 46 Engagement fitting 53 Adsorption part 112,113 Winding section 112a, 113a Upper end of winding portion

Claims

1. A mounting structure for a communication or power cable that is stretched between a first member and a second member of a bridge, an excess length portion provided in the vicinity of an end portion of the first member or the second member of the cable; an excess length holding member that holds an excess length of the cable at a holding position set on the first member or the second member; a retention release mechanism that releases retention of the excess length of the cable by the excess length retaining member when a relative displacement exceeding a reference value occurs between the first member and the second member, thereby allowing the excess length to be extended; Equipped with the excess length holding member includes a linear member that connects the excess length of the cable to the first member or the second member, The retention release mechanism includes a tension member to which a tension force is applied when a relative displacement exceeding a reference value occurs between the first member and the second member, and a cutting member that cuts the linear member of the excess portion retention member by the tension force of the tension member. A bridge-attached cable mounting structure characterized by the above.

2. 2. The bridge-attached cable mounting structure according to claim 1, the tension member of the retention release mechanism is formed of a linear member having a strength greater than that of the linear member of the excess portion retention member, A mounting structure for a bridge-attached cable, characterized in that the cutting member of the holding release mechanism is formed by bending back one end of the linear member serving as the tension member, and is formed by a ring-shaped portion that engages with the linear member of the excess portion holding member.

3. 2. The bridge-attached cable mounting structure according to claim 1, the tension member of the hold release mechanism is formed of a linear member, A mounting structure for a bridge-attached cable, characterized in that the cutting member of the holding release mechanism is formed by a cutting blade that is driven by the tensile force of the linear member serving as the pulling member to cut the linear member of the excess length holding member.

4. A mounting structure for a communication or power cable that is hung between a first member and a second member of a bridge, an excess length portion provided in the vicinity of an end portion of the first member or the second member of the cable; an excess length holding member that holds an excess length of the cable at a holding position set on the first member or the second member; a retention release mechanism that releases retention of the excess length of the cable by the excess length retaining member when a relative displacement exceeding a reference value occurs between the first member and the second member, thereby allowing the excess length to be extended; Equipped with the excess length holding member includes an engaging fitting that engages with the first member or the second member, A mounting structure for a bridge-attached cable, characterized in that the retention release mechanism includes a tensioning member that applies a tensile force when a relative displacement exceeding a reference value occurs between the first member and the second member, and this tensile force releases the engagement of the engaging fitting with the first member or the second member.

5. A mounting structure for a communication or power cable that is hung between a first member and a second member of a bridge, an excess length portion provided in the vicinity of an end portion of the first member or the second member of the cable; an excess length holding member that holds an excess length of the cable at a holding position set on the first member or the second member; a retention release mechanism that releases retention of the excess length of the cable by the excess length retaining member when a relative displacement exceeding a reference value occurs between the first member and the second member, thereby allowing the excess length to be extended; Equipped with the slack portion holding member includes a magnet that attracts the slack portion of the cable to the first member or the second member, A mounting structure for a bridge-attached cable, characterized in that the retention release mechanism includes a tensioning member that applies a tensioning force when a relative displacement occurs between the first member and the second member that exceeds a reference value, and this tensioning force releases the magnet from its attraction to the first member or the second member.

6. The bridge-attached cable mounting structure according to claim 1, 4 or 5, A mounting structure for a bridge-attached cable, characterized in that the tension member of the retention release mechanism is connected to one of the first and second members which is different from the member in which the excess length portion whose retention is released by the retention release mechanism is located.

7. The bridge-attached cable mounting structure according to claim 1, 4 or 5, A bridge-attached cable mounting structure, characterized in that the excess length of the cable at the holding position is bent in a mountain shape.

8. The bridge-attached cable mounting structure according to claim 1, 4 or 5, A bridge-attached cable mounting structure, characterized in that the excess length of the cable at the holding position is bent in an eight-shape.

9. The bridge-attached cable mounting structure according to claim 1, 4 or 5, A mounting structure for a bridge-attached cable, characterized in that the excess portion of the cable at the holding position is formed by two wound portions wound in opposite directions.

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