JP6975212B2 - Buckling prevention structure for steel closed cross-section members of steel bridges - Google Patents

Description

The present invention relates to a buckling prevention structure for a steel closed cross-section member of a steel bridge and a construction method thereof.

With respect to the terms in the specification, the term "pressure-bearing bolt" is a one-sided bolt realized by a high-strength bolt made of a material such as a high-strength bolt, and is at least one of a plurality of members to be joined. A bolt or screw that is screwed directly into a prepared hole that has not been machined with a female thread to advance while threading itself, form a female thread by plastic deformation, and join the thread. TRS (registered trademark). Also included are bolts or threads that are threaded and threaded on their own, forming female threads by elastic deformation or by cutting and threading, and also so-called thread rolling threads, threads. It must be interpreted as a concept that includes forming screws, tapping screws and tap bolts.

The term "one-side bolt" is used to penetrate a plurality of members to be joined, for example, through a flange of a stiffener and a web or flange of a steel closed cross section member, and the flange of the stiffener, which is one member. It must be interpreted as a concept that includes bolts or screws that are pressure-bonded by construction from the side.

In recent years, large earthquakes have occurred frequently, and there has been a strong demand for seismic retrofitting of existing steel bridges. Seismic retrofitting of existing Nagao Bridges with a large bridge length and a maximum span length of more than 200 m is not covered by the Road Bridge Specification (edited by the Nippon Road Association), and is earthquake resistant for those involved. It is difficult to design a structure for reinforcement.
A method for repairing fatigue cracks in a weld metal in a steel deck of an existing steel bridge is disclosed in Non-Patent Document 1, and a thread rolling screw and TRS (Non-Patent Document 2) are used in the method. This prior art does not disclose structures that improve seismic performance of steel bridges.

Especially in Nagao Bridge, the members such as the chords of the truss structure have a box-shaped cross section forming a closed space in order to improve the rigidity, and the behavior of each member at the time of an earthquake is complicated. Conventionally, analysis and design methods for what kind of force acts on which part, which member, and what kind of destruction may occur when an earthquake occurs are already established technologies. However, there is a structure that not only improves the seismic performance of steel bridges and effectively retrofits them, but also has excellent airtightness of closed spaces, airtightness of watertightness, and construction workability in steel closed cross-section members. do not.

Yoshiaki Mizogami, Akira Moriyama, Yoshihiro Kobayashi, Masahiro Sakano: Proposal of bottom surface repair method for U-rib steel deck bead penetration crack, JSCE Proceedings A1 (Structural and Seismic Engineering), Vol.73, No.2, 456-472 , 2017. Hiroyuki Suzuki: Experimental Study on Strength of Joints Joined with Thread Rolling Threads, Proceedings of Structural Engineering, Vol. 61A, pp. 614-626, 2015

An object of the present invention is to improve the seismic performance of an existing steel bridge, and to provide a seat for a steel closed cross section member which is excellent in airtightness of a closed space, watertightness, and construction workability in a steel closed cross section member. It is to provide a buckling prevention structure and a construction method thereof.

The present invention
It is a buckling prevention structure of the steel closed cross-section member 121 of the steel bridge 100.
The steel closed cross-section member 121 has a web 150 and a flange 152 forming a closed space, and has diaphragms 145 and 148 in the closed space.
Includes steel stiffener 156 and bearing bolt 181
The steel stiffener 156 has a flange 171 and a rib 172 forming a T-shaped cross section or an L-shaped cross section, and the flange 171 of the steel stiffener 156 is made of steel along the steel closed cross-section member 121 . Placed on the outer surface of the web 150 or flange 152 of the closed cross-section member 121, avoiding the positions of the diaphragms 145 and 148.
A flange 171 and the web 150 or flange 152 of the steel closed-section member 121 of the steel stiffener 156 through, at intervals in the longitudinal direction of the steel stiffener 156 and the steel closed-section member 121 , Multiple pilot holes for bearing pressure joining 197 and 198 were drilled in advance, respectively.
The bearing bonding bolt 181 is a one-side bolt realized by a high-strength bolt, and is engraved with a male screw having an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the bearing bonding pilot holes 197 and 198. that has a shaft portion 193, the bearing capacity bonding pilot holes 197 and 198 toward the web 150 or flange 152 of the steel closed-section member 121 from the flange 171 of the steel stiffener 156, by being screwed, the internal thread the forming a willing Bearing joint hole 186 with its own formation, and characterized in that the web 150 or flange 152 of the flange 171 and the steel closed-section member 121 of the steel stiffener 156 Bearing joined It is a buckling prevention structure of a steel closed cross section member of a steel bridge.

The steel closed cross-section member constituting the steel bridge in the present invention has a closed space formed by a web and a flange, and is configured to include a diaphragm in the closed space. The diaphragm stiffens the closed cross-sectional member of the box-shaped cross section so that the secondary stress associated with the cross-sectional deformation is reduced so that the cross-sectional shape can be maintained. The present inventor has clarified that a compressive load acts on a closed-section member of a steel bridge due to an earthquake, and therefore it is important to stiffen the closed-section member in order to improve the seismic performance of the steel bridge. The member on which the compressive load due to the occurrence of an earthquake acts may be, for example, a lower chord member, a middle chord member, or an upper chord member constituting a steel girder such as a horizontal truss of a truss girder of a long bridge. The steel stiffener has flanges and ribs that form a T-shaped or L-shaped cross section. Along the closed cross-section member, the stiffener flange is placed on the web of the steel closed-section member or on the outer surface of the flange. For example, the longitudinal axis of each stiffener and the longitudinal axis of the closed section member are parallel in a virtual plane, and the stiffener flange is either the web or the flange of the closed section member, for example, the web. Placed on the outer surface of the web or on the outer surface of both the web and the flange. The stiffener is arranged so as to avoid the position of the diaphragm. For example, in a configuration in which a plurality of diaphragms are provided in the longitudinal direction of the closed cross-section member, the stiffener is arranged so as to extend between the two diaphragms so as not to overlap the position of the diaphragm. Will be done.

Through the flange of the stiffener and the web or flange of the steel closed cross-section member, a plurality of pilot holes for bearing pressure joining are drilled in advance at intervals in the longitudinal direction between the stiffener and the closed cross-section member. Will be done. Therefore, the pilot hole for bearing pressure joining of the flange of the stiffener and the prepared hole for bearing pressure joining of the web of the closed cross-section member or the flange have axes on a common straight line, respectively, and have an inner diameter D11. For example, the inner diameters D11 of the pilot holes for bearing pressure joining adjacent in the longitudinal direction may be different from each other.

Bolts for bearing pressure joints are one-side bolts realized by high-strength bolts. A male screw having an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the pilot hole for bearing pressure joining is engraved on the shaft portion of the bearing pressure joining bolt. The shaft portion of the bearing pressure joining bolt is screwed into each bearing bearing pilot hole between the flange of the stiffener and the web or flange of the closed cross-section member in this order, and the female screw is formed by itself to support the bearing. Form a pressure junction hole. In this way, the pressure-supporting bolt supports the flange of the stiffener and the web or flange of the closed cross-section member.

Therefore, the closed cross-section member is reinforced by the stiffener, and buckling of the closed cross-section member due to the compressive force generated at the time of an earthquake can be prevented. Stiffener improves smaller cross section parameters R _R associated with width-thickness ratio in the reference load bearing capacity curve of allowable stress for local buckling of the closed-section member, Buckling load force, i.e., buckling buckling The stress degree σcr is improved.

Since the bearing bearing bolt used in the present invention is screwed into the hole wall of the bearing bearing pilot hole while forming a female screw, the airtightness and watertightness of the threaded portion in the formed bearing bearing hole are high. .. Even if the inner surface of the closed cross-section member facing the closed space is not coated with anti-corrosion coating, the anti-corrosion performance does not deteriorate and the anti-corrosion performance is prevented. It is preferably carried out for steel bridges such as Nagao Bridge.

According to the pressure-bearing joint of the present invention, the work can be performed while leaving the coating film on the web of the closed cross-section member facing the flange of the stiffener or the surface of the flange, so that it is high in combination with high airtightness. Anticorrosion performance can be achieved. The present inventor has confirmed that this coating film does not cause peeling or cracking of the coating film even after the completion of the pressure-supporting bonding.

Friction joining with high-strength bolts will be readily conceivable to those skilled in the art for joining stiffeners to closed section members. In the friction joining method using high-strength bolts, a common bolt accommodation hole with a diameter larger than that of the shaft of the high-strength bolt with a head is drilled in the flange of the stiffener and the web or flange of the closed cross-section member. Insert the shaft of the high-strength bolt from one side and screw the nut on the other side. There are many problems with this configuration. That is, it is necessary to construct the closed cross-section member on both the inside and outside of the web or the flange, and the construction workability is inferior. In addition, according to the seismic reinforcement work in which this stiffener is frictionally joined with high-strength bolts, the inner diameter of the bolt accommodation hole is larger than the outer diameter of the high-strength bolt, so there is an unavoidable gap, and airtightness and watertightness are present. Poor sexual airtightness. Therefore, air and rainwater invade the closed space of the closed cross-section member, and especially in a steel bridge erected in a strait area where the corrosive environment is severe, air and rainwater containing flying salt invade the inside of the member and close. The anticorrosion performance of the space is reduced. Furthermore, in this frictional joining, the coating film on the web of the closed cross-section member facing the flange of the stiffener or the outer surface of the flange must be removed to form a steel base, and thus the corrosion resistance is inferior from this viewpoint as well. .. In order to ensure airtightness, a bolt cap that covers the head or nut of a high-strength bolt exposed to the outside of the closed cross-section member and a sealing material that applies the vicinity of the bolt cap are required, and maintenance costs are high. It's bulky.

The present invention solves many of the above-mentioned problems and enables seismic retrofitting with high airtightness in a closed space of a closed cross-section member, so that maintenance costs can be reduced. The present invention can be realized without hindering the use of roads, train tracks, etc., without traffic restrictions, traffic closures, etc., and with simple construction workability outside the closed cross-section member.

In the present invention, the bearing joint bolt 181 is screwed into the bearing pilot holes 197 and 198 of both the flange 171 of the stiffener 156 and the web 150 or the flange 152 of the closed cross-section member 121, respectively. However, in another embodiment, the flange 171 of the stiffener 156 is formed with a flexible hole in place of the pressure-supporting pilot hole 197, and is used for pressure-supporting bonding of the web 150 of the closed cross-section member 121 or the flange 152. It may be configured to form a bearing joint hole 187 (FIG. 12) by being screwed only into the prepared hole 198.

The present invention
When a predetermined longitudinal compressive load is applied to the steel closed cross-section member 121, among the bearing bolts 181 forming the row, the bearing bolts 181 existing near the center of the row are closer to the end of the row. The pressure-bearing bolt 181 present in the steel closed cross-section member 121 does not pull out from the pressure-bearing joint hole 187 of the web 150 or the flange 152, and is present at least near the end of the row. as the shank 193 of the bolt 181 does not shear failure, the mechanical strength of the flange 171 and the web 150 or flange 152 of the steel closed-section member 121, as well as bearing capacity joining bolt 181 steel stiffeners 156 are determined It is characterized by.

According to the present invention, even if a shearing force acts on the bearing bearing bolt due to the longitudinal compressive force generated in the closed cross section member during an earthquake, the bearing bearing bolt is the bearing joining of the web or flange of the closed cross section member. Even if a part of all the bearing bolts are sheared and broken without being pulled out from the hole, the stiffener is a closed cross section member due to the bearing bolts that do not shear and break the rest. Each broken part of the bearing bearing bolt that has been sheared and broken does not come out of the bearing joint hole where the female thread is cut. Therefore, the excellent effect that each broken portion of the bearing bearing bolt does not fall, the stiffener does not fall, and the safety under the seismic retrofitting portion is maintained is achieved.

According to the idea of the present inventor, when a compressive load is applied to a closed cross-section member due to an earthquake, the flange of the stiffener and the web or flange of the closed cross-section member form one row or a plurality of parallel supports. In the joint of the present invention, which is pressure-bonded by the pressure-bonding bolt, almost no shearing force acts on the shaft of the intermediate pressure-bonding bolt, which is located near the center of the row, and is located near the end of the row. So to speak, there is a phenomenon that the shaft portion of the bearing bearing bolt at the end receives most of the large shearing force. Therefore, when the compressive load acting on the closed cross-section member increases, the acting force of the bearing bearing bolt at the end increases, and the acting force becomes smaller toward the center side one after another. It acts on the bearing bolts adjacent to it. Therefore, when the same bearing joint is performed with each bearing bonding bolt having the same configuration, the shaft portion of the bearing bearing bolt at the end is sheared and fractured before the shaft portion of the intermediate bearing bonding bolt. This phenomenon is remarkable when the number of bearing bonding bolts in each row arranged in the direction of receiving the compressive load is, for example, 6 or more, further 10 or more, and the joint range is relatively long.

In the present invention, when a predetermined longitudinal compressive load assumed at the time of an earthquake or the like is applied to the closed cross-section member, a large shearing force acts as compared with the intermediate bearing bonding bolt, at least the end support. The mechanical strength is determined so that the pressure bonding bolt does not undergo shear failure. Therefore, even if a compression load equal to or higher than the predetermined value is applied to the closed cross-section member and the bolt for bearing pressure joining at the end is sheared and broken, a part of the shaft portion that has been sheared and broken is a male screw. Because it was screwed in, it did not pull out from the pressure joint hole of the web or flange of the closed cross section member due to locking such as plastic deformation and elastic deformation with the screw, did not fall, and was sheared and broken. Similarly, the remaining part on the head side of the shaft does not pull out from the bearing joint hole of the stiffener flange, does not fall, and is not sheared and broken by the intermediate bearing bonding bolt. The stiffeners do not fall, and by not falling, safety is ensured below their seismic reinforcement sites.

The mechanical strength is the mechanical structure, mechanical properties, and physics associated with the flange of the stiffener, the web or flange of the closed cross-section member, and the bearing bolt to ensure safety by not falling. It is a value determined by physical characteristics, physical properties and other factors. To achieve its mechanical strength, for example, the dimensions and materials of the bearing bolts, the number of bearing bolts and the spacing between the bearing bolts, and the flange of the stiffening material on which the bearing holes are formed. And the thickness and material of the web or flange of the closed-section member, as well as their rigidity, etc. are selected.

The mechanical strength may be achieved by a configuration in which the same bearing joint is made with each bearing bonding bolt having the same configuration. For example, by calculating the required number of bolts with an equal load on all bolts and configuring it so that at least the end bolts do not break as a result if it is within the assumed seismic force, not only the intermediate bearing bearing bolts but also the end bolts. You may also try to obtain mechanical strength that does not break by shearing. Alternatively, even if it can be achieved by a configuration in which the mechanical strength related to the end bearing bolt is larger than the mechanical strength related to the intermediate bearing bolt. Often, for that purpose, for example, the outer diameter of the bearing bearing bolt at the end may be selected to be larger than that of the intermediate bearing bearing bolt for bearing bonding.

The present invention
The steel closed cross-section member 121 is characterized by being chords 112, 117, 121 of the horizontal truss 110 of the truss girder 104 of the cable-stayed bridge 100.

The present invention
The chord members 112, 117, 121 of the horizontal truss 110 are lower chord members 121, and are
The stiffening range of the steel stiffener 156 is characterized in that it is selected between the diaphragms 15645 and 148 near the main tower 103.

According to the present inventor, in the prior art in which the stiffener of the present invention is not provided, for example, in a three-span continuous steel truss cable-stayed bridge of a road railroad combined bridge which is a long bridge in the strait of a steel bridge, the present invention is used. According to the seismic performance verification analyzed by the person, it was confirmed that a predetermined compressive load was applied to the lower chord material of the horizontal truss near the main tower, and the damage tolerance was exceeded on the web. Therefore, a stiffener is provided on the web of the lower chord material of the horizontal truss, whereby the width-thickness ratio that determines the allowable compressive stress degree in consideration of the local buckling of the web of the lower chord material can be reduced. In the horizontal truss lower chord material configured to be symmetrical with respect to the vertical symmetrical plane 111 (FIGS. 1 and 2) in the cross section of the horizontal truss, the horizontal truss lower chord material is supplemented symmetrically with respect to the symmetrical plane 111. A rigid material is provided. The stiffener is placed between the diaphragms in the longitudinal direction to avoid the position of the diaphragms.

The present invention
It is a construction method of a buckling prevention structure of a steel closed cross-section member 121 of a steel bridge 100.
The steel closed cross-section member 121 has a web 150 and a flange 152 forming a closed space, and has diaphragms 145 and 148 in the closed space.
Prepare the steel stiffener 156 and the pressure bonding bolt 181 and prepare.
The steel stiffener 156 has a flange 171 and a rib 172 forming a T-shaped cross section or an L-shaped cross section, and the flange 171 of the steel stiffener 156 has a plurality of pilot holes 197 for bearing pressure joining. performs pilot hole drilling step for Bearing joining steel stiffener 156 longitudinally spaced apart to drilling in rows of steel stiffener 156,
The flange 171 of the steel stiffener 156, along the steel closed-section member 121 to the outer surface of the web 150 or flange 152 of the steel closed-section member 121 while avoiding the position of the diaphragm 145, 148 are arranged,
By Bearing bonding prepared hole 197 of the flange 171 of the steel stiffener 156, the steel for drilling a web 150 or Bearing bonding prepared hole 198 in the flange 152 of the steel closed-section member 121 to guide the blade of the drilling tool performs pilot hole drilling step for Bearing junction of manufacturing closed-section member 121,
The bearing bearing bolt 181 is a one-side bolt realized by a high-strength bolt, and is a shaft portion on which a male screw having an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the bearing bearing pilot hole is engraved. Has 193 and
The Bearing joining bolt 181, the bearing capacity bonding pilot holes 197 and 198 toward the web 150 or flange 152 of the steel closed-section member 121 from the flange 171 of the steel stiffener 156, by screwing, itself an internal thread proceed while forming to form a bearing capacity joining hole 186 and 187, steel stiffener 156 Bearing joining the web 150 or flange 152 of the flange 171 and the steel closed-section member 121 of the steel stiffener 156 and a method of constructing the anti-buckling structure of steel closed-section member of steel bridge and performing Bearing bonding step between the steel closed-section member 121.

According to the present invention, it is possible to construct a buckling prevention structure that improves seismic performance when a compressive load in the longitudinal direction is applied to a closed cross section member of an existing steel bridge during an earthquake.

After drilling a plurality of pressure-bearing joint pilot holes in a row on the web or flange of the closed-section member, the work of sequentially screwing and tightening each pressure-bearing joint bolt (that is, the pressure-supporting joint bottom of the closed-section member). The drilling step is performed for each of the multiple bearing bolts, and then the bearing step of the stiffener and the closed cross section member is performed for each of the multiple bearing bolts). Preferably, for each bearing bonding bolt, an operation of drilling a bearing bonding pilot hole in the web or flange of the closed cross-section member, and an operation of screwing and tightening the bearing bonding bolt into the drilled bearing bearing pilot hole. (That is, after performing the pilot hole drilling step for pressure-bearing joining of the closed-section member for one pressure-supporting bolt, the pressure-supporting joining step between the stiffener and the closed-section member is performed. By performing this operation for one pressure-supporting bolt and repeating this operation for each pressure-supporting bolt, the closed space of the closed-section member can be used to create a pressure-supporting pilot hole in the web or flange of the closed-section member. Since the time for communicating with the outside can be shortened, the risk of water such as rainwater can be reduced, and the axis of the pilot hole for bearing pressure joining of the flange of the stiffener and the web or flange of the closed cross section member can be reduced. It is ensured that the bearing bolt is screwed in accurately while keeping the axis of the pilot hole for bearing bearing exactly aligned.

The present invention
Temporary fastening bolts 200 having a shaft portion 207 in which a male screw having an outer diameter D22 (D22 <D11) which is less than the inner diameter D11 of the pilot holes for bearing pressure joining 197 and 198 are engraved are prepared.
Interchange hole drilling step for temporary fastening to drilling the pinning flexibility hole 201 for longitudinally in the flange 171 of the steel stiffener 156 at both ends near temporary fastening bolts 200 of the steel stiffener 156 The temporary fastening accommodation hole 201 has an inner diameter D32 equal to the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining.
The web 150 or flange 152 of the steel closed-section member 121, steel closed section for drilling the inner diameter D12 under a temporary fixing hole 202 having a (D12 <D11) of less than the inner diameter D11 of Bearing bonding prepared hole 197,198 Perform a pilot hole drilling step for temporary fastening of member 121,
The outer diameter D22 of the shaft portion 207 of the temporary fixing bolt 200 is selected to have a value exceeding the inner diameter D12 of the temporary fixing pilot hole 202 (D12 <D22 <D11).
By inserting the temporary fastening bolt 200 into the temporary fastening pilot hole 202 by inserting the temporary fastening flexible hole 201 of the flange 171 of the steel stiffener 156 and screwing it into the temporary fastening pilot hole 202, the steel is advanced while forming a female screw by itself. performs temporary fastening step of the tacked state of close contact with the web 150 or flange 152 of the flange 171 and the steel closed-section member 121 of the manufacturing stiffener 156,
In this temporarily fastened state, performs the bearing capacity bonding step of the Bearing pilot hole drilling step for joining the steel closed-section member 121, and a steel stiffener 156 and the steel closed-section member 121,
After that, the temporary fastening bolt 200 is removed, the inner diameter D12 of the temporary fastening pilot hole 202 is expanded to the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining, and the steel stiffener 156 is increased by the bearing bonding bolt 181. It is characterized in that a temporary fastening diameter expansion bearing pressure joining step is performed in which the flange 171 and the web 150 or the flange 152 of the steel closed cross section member 121 are pressure-bonded.

According to the present invention, a flexible hole for temporary fixing is formed in the flange of the stiffener near both ends in the longitudinal direction of the stiffener (flexible hole drilling step for temporary fastening). This temporary fastening flexible hole is a so-called stupid hole that exceeds the outer diameter D22 of the shaft portion of the temporary fastening bolt, and has an inner diameter D32 (D22 <D32 ≦ <D11) that is equal to or less than the inner diameter D11 of the pilot hole for bearing pressure joining. .. D32 = D11 may be used, but D32 <D11 may be used. The temporary fastening bolt is screwed into the temporary fastening pilot hole (the temporary fastening pilot hole drilling step in the closed cross-section member) that has been drilled in the web or flange of the closed cross-section member through the temporary fastening flexible hole. By tightening, the flange of the stiffener and the web or flange of the closed cross-section member can be brought into close contact with each other to form a temporary fastening state with no skin gap (temporary fastening step). Therefore, in the residual portion in the longitudinal direction of the stiffener, the flange of the stiffener and the web or flange of the closed cross-section member can be pressure-bonded by the pressure-supporting bolt with as little skin gap as possible. (The pilot hole drilling step for pressure-bearing joining of a closed cross-section member, and the pressure-supporting joining step of a stiffener and a closed-section member). After that, when the temporary fastening bolt is removed and the inner diameter D32 of the temporary fastening accommodation hole is less than the inner diameter D11 of the pilot hole for bearing pressure joint (D32 <D11), the inner diameter D32 of the temporary fastening accommodation hole and the temporary fastening are temporarily fastened. The inner diameter D12 of the pilot hole can be enlarged and expanded, and the bearing can be joined by the bearing bolt (temporary fastening diameter expansion bearing joining step).

The present invention
Prepare the attracting means 200a and
Performs drawn for operation hole boring step of boring the operation holes 201a for drawn for longitudinally inboard with means 200a for attracting the flange 171 of the steel stiffener 156 steel stiffeners 156,
Before performing the pilot hole drilling step for pressure-bearing joining of the steel closed cross-section member 121 in the temporary fastening state by the temporary fastening step,
The web 150a or flange 152a of the steel closed-section member 121, steel closed section for drilling a drawn for locking hole 202a has an inner diameter less than the inner diameter D11 of Bearing bonding pilot holes 197,198 D12a (D12a <D11) Perform the locking hole drilling step for pulling the member 121,
The drawn-along means 200a, in relation to the drawn for operation hole 201a and attracted a locking hole 202a of the flange 171 of the steel stiffener 156, the operation from the side of attraction for operation hole 201a, steel stiffening A pulling step is performed in which the flange 171 of the material 156 and the web 150 or the flange 152 of the steel closed cross-section member 121 are brought into close contact with each other.
In this pulled state, performs the bearing capacity bonding step of the Bearing pilot hole drilling step for joining the steel closed-section member 121, and a steel stiffener 156 and the steel closed-section member 121,
After that, the pulling means 200a is removed by an operation from the side of the pulling operation hole 201a, and the inner diameter D12a of the pulling locking hole 202a is expanded to the inner diameter D11 of the pressure-supporting joint pilot holes 197 and 198 to support the pulling means 200a. by compression bonding bolt 181, and performing enlarged Bearing bonding step attracted to bearing capacity joining the web 150 or flange 152 of the flange 171 and the steel closed-section member 121 of the steel stiffener 156.

According to the present invention, an pulling operation hole is formed in the flange of the stiffener near the center in the longitudinal direction of the stiffener (pulling operation hole drilling step). The pulling means is a pulling operation hole in relation to a pulling operation hole and a pulling locking hole drilled in the web or flange of the closed cross-section member (pulling locking hole drilling step of the closed cross-section member). By operating from the side of 201a, for example, by inserting the pulling operation hole and the pulling locking hole, the flange of the stiffener and the web or flange of the closed cross-section member are brought into close contact with each other to eliminate the skin gap. Can be pulled in (pulling step). Therefore, in the residual portion in the longitudinal direction of the stiffener, the flange of the stiffener and the web or flange of the closed cross-section member can be pressure-bonded by the pressure-supporting bolt with as little skin gap as possible. (The step of drilling a locking hole for the pressure-bearing joint of the closed cross-section member, and the step of the pressure-bearing joint between the stiffener and the closed-section member). After that, when the pulling means is removed and the inner diameter D32a of the pulling operation hole 201a is less than the inner diameter D11 (D32a <D11) of the pilot hole for bearing pressure joining, the inner diameter D32a of the pulling operation hole 201a and the pulling staff are used. The inner diameter D12a of the stop hole 202a can be increased in diameter and can be pressure-bonded by a pressure-supporting bolt (pull-diameter expansion-supporting pressure joining step). The pulling operation hole 201a is a so-called stupid hole that exceeds the outer diameter D22 of the shaft portion of the pulling bolt, and has an inner diameter D32a (D22 <D32a ≦ <D11) that is equal to or less than the inner diameter D11 of the pilot hole for bearing pressure joining. D32a = D11 may be used, but D32a <D11 may be used.

The present invention
The pulling means is a pulling bolt 200a having a shaft portion 207a in which a male screw having an outer diameter D22a (D22a <D11) having an inner diameter D22a (D22a <D11) smaller than the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining is engraved.
The drawn for operation hole drilling step, and drilling the drawn for operation hole 201a for longitudinal center toward a bolt 200a for attracting the flange 171 of the steel stiffener 156 steel stiffeners 156,
In the locking hole drilling step for pulling the steel closed cross-section member 121,
A pulling locking hole 202a having an inner diameter D12a (D12a <D11) smaller than the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining is drilled in the web 150 or the flange 152 of the steel closed cross-section member 121.
The outer diameter D22a of the shaft portion 207a of the pulling bolt 200a is selected to have a value exceeding the inner diameter D12a of the pulling locking hole 202a (D12a <D22a ≦ D11).
In the pulling step, the pulling bolt 200a is screwed into the pulling locking hole 202a by inserting the pulling operation hole 201a of the flange 171 of the steel stiffener 156, thereby forming a female screw by itself. in a state attracted in close contact with the web 150 or flange 152 of the flange 171 and the steel closed-section member 121 of the steel stiffener 156,
The pulling diameter expansion bearing joint step is characterized in that the pulling bolt 200a is removed by an operation from the side of the pulling operation hole 201a.

According to the present invention, an pulling operation hole is formed in the flange of the stiffener near the center in the longitudinal direction of the stiffener (pulling operation hole drilling step). As described above, this pulling operation hole is a so-called stupid hole that exceeds the outer diameter D22a of the shaft portion of the pulling bolt, and has an inner diameter D32a (D22a <D32a ≦ <D11) that is equal to or less than the inner diameter D11 of the pilot hole for bearing pressure joining. It is a flexible hole having. By screwing and tightening the pulling bolt into the pulling locking hole (the pulling locking hole drilling step of the closed cross-section member) drilled in the web or flange of the closed cross-section member through the pulling operation hole. , The flange of the stiffener and the web or flange of the closed cross-section member can be brought into close contact with each other to eliminate the skin gap (pulling step). Therefore, in the residual portion in the longitudinal direction of the stiffener, the flange of the stiffener and the web or flange of the closed cross-section member can be pressure-bonded by the pressure-supporting bolt with as little skin gap as possible. (The pilot hole drilling step for pressure-bearing joining of a closed cross-section member, and the pressure-supporting joining step of a stiffener and a closed-section member). After that, the pulling bolt can be removed, the inner diameter D12a of the pulling locking hole can be enlarged and expanded in diameter, and the bearing bonding bolt can be used for bearing bonding (pulling diameter expansion bearing bonding step).

The present invention
The steel closed cross-section member 121 of a steel bridge has a web 150 and a flange 152 forming a closed space, and a diaphragm 145, 148 is provided in the closed space.
Includes steel stiffener 156 and bearing bolt 181
The steel stiffener 156 has a flange 171 and a rib 172 forming a T-shaped cross section or an L-shaped cross section, and the flange 171 of the steel stiffener 156 is made of steel along the steel closed cross-section member 121 . Placed on the outer surface of the web 150 or flange 152 of the closed cross-section member 121, avoiding the positions of the diaphragms 145 and 148.
The web 150 or flange 152 of the flange 171 and the steel closed-section member 121 of the steel stiffener 156 through, at equidistant intervals in the longitudinal direction of the steel stiffener 156 and the steel closed-section member 121 The pilot holes 197 and 198 for bearing pressure joining having the same structure are drilled in advance, respectively.
Each of the plurality of bearing bonding bolts 181 is a one-side bolt having the same structure and realized by high-strength bolts, and has an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the bearing bonding pilot holes 197 and 198. ) has a shaft portion 193 that the external thread is engraved with, under a pressure bearing joint hole toward the web 150 or flange 152 of the steel closed-section member 121 from the flange 171 of the steel stiffener 156 197,198 to, by being screwed, proceed while forming itself an internal thread forms a bearing capacity joining hole 186 and 187, the flange 171 and the web 150 or flange 152 of the steel closed-section member 121 of the steel stiffener 156 Pressure-bonded,
Flange 171 and web 150 or flange 152 of the steel closed-section member 121 of the steel stiffener 156, and the mechanical strength of Bearing joint bolt 181,
When a predetermined longitudinal compressive load is applied to the steel closed cross section member 121, among the bearing bolts 181 forming the row, the bearing bolts 181 existing near the center of the row are closer to the end of the row. The pressure-bearing bolt 181 present in the steel closed cross-section member 121 does not pull out from the pressure-bearing joint hole 187 of the web 150 or the flange 152, and is present at least near the end of the row. It is a method of designing a buckling prevention structure of a steel closed cross section member of a steel bridge, characterized in that the shaft portion 193 of the bolt 181 is determined so as not to be sheared and broken.

According to the idea of the present inventor, the flange 171 of the stiffener 156 and the web 150 or the flange 152 of the closed cross-section member 121 are drilled in rows at equal intervals in their longitudinal directions. In the joint of the present invention in which a plurality of bearing bonding bolts 181 having the same structure are screwed into the bearing bonding pilot holes 197 and 198 having the same structure, respectively, the compression load is applied to the closed cross-section member 121 due to an earthquake. When the action is applied, the shearing force does not work on the shaft of the intermediate bearing joint bolt 181 that exists near the center of the row as compared with the end, and it exists near the end of the row, so to speak. There is a phenomenon that the shaft part of the bearing-supporting bolt of the part receives most of the large shearing force. According to the present invention, the mechanical strength of the flange 171 of the stiffener 156, the web 150 or the flange 152 of the closed cross section member 121, and the bearing bolt 181 is greater than the shearing of the bearing bolt 181 in the middle of the row. The shaft portion 193 of the bearing joint bolt at the end of the row receiving the force is determined so as not to be sheared and broken when a predetermined longitudinal compressive load is applied to the closed cross section member 121. This ensures seismic retrofitting. For example, by calculating the required number of bolts with an equal load on all bolts and configuring the end bolts so that they do not break as a result if they are within the assumed seismic force, not only the intermediate bearing bearing bolts but also at least the end bolts. Also obtains mechanical strength that does not break by shearing.

FIG. 3 is a cross-sectional view perpendicular to a bridge axis showing a horizontal truss 110 constituting the superstructure 101 of a part of the steel bridge 100 according to the embodiment of the present invention. FIG. 3 is a cross-sectional view showing one portion on the right side of FIG. 1 with respect to the plane of symmetry 111 of the lower chord member 121 of the horizontal truss 110. FIG. 3 is an enlarged side view showing a part of FIG. 2. It is sectional drawing seen from the cut surface IV-IV of FIG. It is sectional drawing seen from the cut plane line VV of FIG. It is sectional drawing seen from the cut plane line VI-VI of FIG. It is sectional drawing seen from the cut plane line VII-VII of FIG. It is a side view which shows a part of a steel bridge 100. It is a side view which shows a part of the residue following FIG. 8 of a steel bridge 100. It is a simplified horizontal sectional view of the lower chord member 121 and the lower horizontal structure 169 of the horizontal truss 110 in the portion corresponding to FIG. 8 of the steel bridge 100. It is a perspective view which shows a part of the horizontal truss 110, the main structure truss 131, and the lower horizontal structure 169. It is sectional drawing which shows the state which fixed the stiffener 156 to the web 150 of the lower chord member 121 of a horizontal truss 110 by the bearing joint. It is a figure which shows the plane and the side surface of the bearing bolt 181. It is a flowchart which shows the method of constructing the buckling prevention structure on the lower chord member 121 of the horizontal truss 110 of the steel bridge 100 in one Embodiment of this invention. It is a side view for demonstrating the operation order of fixing a stiffener 156 to a web 150 of a lower chord member 121 by a pressure-bearing joint. It is sectional drawing for explaining the operation of temporarily fixing the stiffener 156 to the web 150 of the lower chord member 121 by the temporary fixing bolt 200, and also explaining the pulling operation by the pulling bolt 200a. It is sectional drawing for demonstrating the operation of bearing-bonding the stiffener 156 to the web 150 of the lower chord member 121 by the pressure-bearing bonding bolt 181. It is sectional drawing which also shows the state which the stiffener 156 is temporarily fastened to the web 150 of the lower chord member 121 by the temporary fastening bolt 200, and the state which is pulled by the pulling bolt 200a. It is a flowchart which shows the method of constructing the buckling prevention structure on the lower chord member 121 of the horizontal truss 110 of the steel bridge 100 in another embodiment of this invention. It is a side view for demonstrating the operation order of fixing the stiffener 156 to the web 150 of the lower chord member 121 by the pressure-bearing joint in each step u1 to u13 of FIG. It is a perspective view of another embodiment of this invention. 22 (1) is a simplified cross-sectional view of the lower chord member 121 of FIG. FIG. 22 (2) is a cross-sectional view of the conventional lower chord member 121. Is a diagram showing the relationship between the ultimate strength σ _{cr /} σ _y is a width-thickness ratio parameter R _R and load bearing capacity in the embodiment of. It is sectional drawing of the lower chord material 121 of still another embodiment of this invention.

FIG. 1 is a cross-sectional view perpendicular to a bridge axis showing a horizontal truss 110 constituting the superstructure 101 of a part of the steel bridge 100 according to the embodiment of the present invention. The steel bridge 100 is, for example, a long bridge bridged in a strait, and is a three-span continuous steel truss cable-stayed bridge. The horizontal truss 110 is configured symmetrically with respect to the vertical symmetrical plane 111 in the bridge axis direction within the cross section of the horizontal truss 110. The upper chord member 112 of the horizontal truss 110 is supported by the middle chord member 117 via the small set vertical members 113 and 114 and the small set diagonal members 115 and 116. The middle chord member 117 is supported by the lower chord member 121 via the central vertical member 118 and the left and right vertical members 119 and 120. The road girder 125, which is the main girder, has a composite structure in which the upper chord member 112 of the horizontal truss 110 and the steel deck 126 are joined by high-strength bolts. In the lower chord member 121, the railroad girders 129 and 130 are supported by the bearings generally indicated by the reference marks 127 and 128 on the left and right with respect to the central vertical member 118, and a road railroad combined bridge is realized.

The upper chord material 112 and the lower chord material 121 of the horizontal truss 110 are joined to the upper chord material 132 and the lower chord material 133 of the main structure truss 131, respectively, and the middle chord material 117 of the horizontal truss 110 is the vertical material 134 of the main structure truss 131. The main structure truss 131 is provided with a diagonal member 135, which is further joined to the truss 131 with reference to FIG. The main truss 131 is assembled by joining the upper chord member 132 and the lower chord member 133 to the vertical member 134 and the diagonal member 135, suspended by the cable 102, and supported by the main tower 103. In the horizontal truss 110, diagonal members 138 and 139 are joined to the vertical member 134 of the main structure truss 131. Due to the above-mentioned synthetic structure, not only the upper chord member 132 of the main truss 131 but also the steel deck 126 can share the horizontal component of the tension of the cable 102, increase the rigidity of the road girder 125, and is advantageous for the road railroad combined bridge. .. The above-mentioned chord members, vertical members, diagonal members, and the like of the horizontal truss 110 and the main structure truss 131 have a rectangular box-shaped closed cross section in order to improve the rigidity. The caisson foundation 105 of the main tower 103 and the end pier 106 form a substructure.

FIG. 2 is a cross-sectional view showing one portion on the right side of FIG. 1 with respect to the symmetrical plane 111 of the lower chord member 121 of the horizontal truss 110, and FIG. 3 is a side view showing a part of FIG. 2 in an enlarged manner. In the closed space of the lower chord member 121, one or more flat plate-shaped diaphragms perpendicular to the longitudinal direction thereof are provided at intervals in the longitudinal direction of the lower chord member 121 (left-right direction in FIG. 1), that is, in the direction perpendicular to the bridge axis. For example, in this embodiment, as shown in FIGS. 2 and 3 on one side with respect to the plane of symmetry 111, a plurality of diaphragms 142 to 149 are provided, and further, a diaphragm without a reference mark is provided.

On the outer surface of one of the webs 150 of the lower chord member 121, the stiffeners 155, 156: 157, and 158 are centered in the longitudinal direction along the longitudinal direction of the lower chord member 121, symmetrically with respect to the plane of symmetry 111 in FIG. It is arranged closer (that is, closer to the plane of symmetry 111 in the direction perpendicular to the bridge axis, closer to the left side in FIG. 2). The stiffeners 155 and 156 are arranged avoiding the positions of the diaphragms 143, 145 and 148 in the longitudinal direction, so that the ends of the stiffeners 155 and 156 are longitudinal to the vicinity of these diaphragms 143, 145 and 148. Although it extends in the direction, it does not overlap in the vertical direction, and the same applies to the residual stiffeners 157 and 158. As shown in FIGS. 1 to 3, the stiffeners 155 and 156 are arranged at the upper and lower center positions of the webs 150 and 151 between the upper and lower flanges 152 and 153, respectively.

4 to 7 are cross-sectional views taken from the cut planes IV-IV, V-V, VI-VI, and VII-VII of FIG. 2, respectively. The lower chord member 121 is configured symmetrically with respect to the vertical symmetrical plane 161 in the direction perpendicular to the bridge axis, and one web 150, the other web 151, and the upper and lower flanges 152 and 153 are welded, fixed, and sealed. Form a closed space. The stiffener 159 is arranged on the other web 151, corresponding to the stiffener 156 on one web 150 of the lower chord member 121. The outer peripheral portions of the diaphragms 142, 143, 145, 148 and 149 are welded and fixed to the upper, lower, left and right inner walls of the closed space formed by the webs 150 and 151 and the flanges 152 and 153. The outer peripheral portions of the diaphragms 144, 146, and 147 are welded and fixed to the upper and left and right inner walls of the closed space. As shown in FIGS. 6 and 7, the lower end of the diaphragms 146 and 147 is above the stiffeners 156 and 159 arranged and fixed to the webs 150 and 151. Therefore, the stiffeners 156 and 159 are arranged between the diaphragms 145 and 148 below the diaphragms 146 and 147, avoiding their vertical positions. The stiffener 155 is arranged below the diaphragm 144, avoiding the vertical position, between the diaphragms 143 and 145, and the same applies to the residual stiffener and the diaphragm. As shown in FIGS. 4 and 5, openings 164 and 165 are formed in the diaphragms 142 and 145, and openings similar to the openings 165 are formed in the diaphragm 148. As shown in FIGS. 3 to 7, the stiffeners 155, 156, 159 and the residual stiffeners are arranged at the vertical center positions of the webs 150 and 151.

FIG. 8 is a side view showing a part of the steel bridge 100, and FIG. 9 is a side view showing a part of the remainder of the steel bridge 100 following FIG. Numbers 1 to 65 in the white circles in FIGS. 8, 9 and 10 and 11 described later are the upper chord member 132, the lower chord member 133, the vertical member 134, and the diagonal members constituting the main structure truss 131 which is one member of the steel truss. The position of the grade of the material 135 is shown, and in the present specification, the number is shown by adding a subscript c. The steel bridge 100 is configured substantially symmetrically in FIG. 8 with respect to the vertical symmetry plane 167 in the direction perpendicular to the bridge axis at the position 33c, and the corresponding symmetrical portions are designated by the same reference numerals.

FIG. 10 is a simplified horizontal sectional view of the lower chord member 121 and the lower horizontal structure 169 of the horizontal truss 110 in the portion of the steel bridge 100 corresponding to FIG. 8, and FIG. 11 shows the horizontal truss 110, the main structure truss 131, and the lower horizontal structure. It is a perspective view which shows a part of structure 169. The horizontal truss 110 and the main truss 131 constitute a truss girder 104. According to the seismic performance verification analyzed by the present inventor, a compressive load acts on the lower chord member 121 of the horizontal truss 110 at the positions 17c to 21c near the main tower 103, and the web of the lower chord member 121 at the positions 17c to 21c. At 150 and 151, it was confirmed that the predetermined allowable value for buckling injury was exceeded. The reason why buckling occurs in these members is that when seismic force acts in the direction perpendicular to the bridge axis, the response of the truss girder tends to increase near the main tower, which is the fulcrum, and the train load is relatively heavy. It is probable that the supporting lower chord material had a greater effect. Therefore, in order to solve the problem of exceeding the permissible value, in one embodiment of the present invention, stiffeners 155 to 159 are provided on the webs 150 and 151 of the lower chord member 121 of the horizontal truss 110 at each position 17c to 21c. .. As a result, the width-thickness ratio that determines the allowable compressive stress degree in consideration of the local buckling of the webs 150 and 151 of the lower chord member 121 can be reduced. In the lower chord member 121 of the horizontal truss 110, which is configured to be symmetrical with respect to the vertical symmetrical plane 111 (FIG. 1) in the cross section of the horizontal truss 110, the lower chord member 121 complements the lower chord member 121 symmetrically with respect to the symmetrical plane 111. A rigid material 155 to 159 is provided. The stiffeners 155 to 159 are arranged between the diaphragms 143, 145, 145 and 148 in the longitudinal direction, and the positions of the diaphragms 143 to 148 are avoided.

FIG. 12 is a cross-sectional view showing a state in which the stiffener 156 is fixed to the web 150 of the lower chord member 121 of the horizontal truss 110 by the pressure bonding of the pressure bonding bolt 181. The stiffener 156 has flanges 171 and ribs 172 that form a T-shaped cross section, is configured symmetrically with respect to the horizontal plane of symmetry 160 of FIG. 12, and along the lower chord member 121, the flange 171 of the stiffener 156. Is arranged on the outer surface of the web 150 of the lower chord member 121, avoiding the positions of the diaphragms 143 to 148 as described above. Regarding the rib 172 of the flange 171 of the stiffener 156, each portion on both sides (upper and lower in FIG. 12) is referred to as a flange portion, and reference numerals 171p and 171q are individually attached and collectively indicated by reference numeral 171.

The bearing joint bolt 181 is a one-side bolt realized by a high-strength bolt, and is a portion of both sides of the rib 172 in the flange 171 of the stiffener 156 in the width direction (vertical direction in FIG. 12) and the lower chord member 121. The bearing holes 186 and 187 are formed by penetrating the web 150 and being screwed into the web 150, and the flange 171 of the stiffener 156 and the web 150 of the steel lower chord member 121 are pressure-bonded.

FIG. 13 is a view showing a plane and a side surface of the pressure-supporting joining bolt 181. The bearing bolt 181 has a hexagonal bolt head 191, a washer portion 192, and a shaft portion 193 integrally formed, and the outer surface thereof is surface-treated to have a higher hardness than the steel materials of the web 150 and the flange 171. NS. The shaft portion 193 having a length below the neck L193 in the pressure joining bolt 181 has a screw portion 194 in which a spiral thread is engraved, and a truncated cone-shaped tip portion 195 having a small diameter. The tip portion 195 guides the axis of the shaft portion 193 and the pilot holes for bearing pressure joining 197 and 198 into a common straight line into the pilot holes 197 and 198 for bearing pressure joining shown in FIG. 17 described later. By rotationally driving the pressure-joining bolt 181 while exerting a pressing force on the bolt head 191 toward the flange 171 and the web 150, the threaded portion 194 of the shaft portion 193 is subjected to bearing pressure welding without female threading. The female threads are formed in the joint pilot holes 197 and 198 by themselves, and the female threads are formed by plastic deformation to achieve the bearing joint, and the bearing joint holes 186 and 187 are formed. The gap between the web 150 and the flange 171 can be made almost zero by using a temporary fixing bolt 200, which will be described later, and a pulling jig and a pulling bolt 200a, which are means for pulling, to prevent the occurrence of skin gaps. It comes off. As described above, the bearing bolt 181 has its axis aligned with the axes of the bearing holes 197 and 198 in a common straight line, and therefore, when the bearing bolt 181 is tightened, the bearing bolt 181 is a bearing bolt. It is possible to prevent the generation of undesired stress due to the bending moment to 181.

According to the bearing bearing bolt 181 the plastic deformation of the female thread does not generate cutting chips, so that such cutting chips do not enter the closed space of the lower chord member 121 and become a source of rust. Further, at the construction site, it is not necessary to perform the screwing work, which tends to reduce the accuracy, so that the workability is improved.

FIG. 14 is a flowchart showing a method of constructing a buckling prevention structure on the lower chord member 121 of the lateral truss 110 of the steel bridge 100 according to the embodiment of the present invention. FIG. 15 is a side view for explaining an operation order in which the stiffener 156 is fixed to the web 150 of the lower chord member 121 by pressure bonding. In FIG. 15 showing the stiffener 156, the reference numerals 1p to 36p and 1q to 36q are the pilot holes 197 for bearing pressure joining formed in the flange portions 171p and 171q, respectively, and the accommodation holes 201 for temporary fixing and the pulling holes described later. The positions of the operation holes 201a are shown, and some of the reference numerals 1p to 36p and 1q to 36q may be omitted so as not to be complicated. Of the positions 1p to 36p and 1q to 36q in FIG. 15, the positions surrounded by thin white circles indicate the positions where temporary fastening or pulling is performed, and the positions surrounded by thick white circles complete the bearing bonding with the bearing bonding bolt 181. Indicates the position of the bolt.

FIG. 16 is a cross-sectional view for explaining an operation of temporarily fixing the stiffener 156 to the web 150 of the lower chord member 121 with the temporary fixing bolt 200, and also explaining the pulling operation with the pulling bolt 200a. .. FIG. 17 is a cross-sectional view for explaining an operation of bearing-joining the stiffener 156 to the web 150 of the lower chord member 121 by the bearing-bearing bolt 181. FIG. 18 is a cross-sectional view showing a state in which the stiffener 156 is temporarily fastened to the web 150 of the lower chord member 121 by the temporary fixing bolt 200 and a state in which the stiffener 156 is pulled by the pulling bolt 200a.

The construction work shown in FIG. 14 will be described with reference to these FIGS. 15-18. Moving from step s1 to step s2 in FIG. 14, the stiffener 156 and the bearing bearing bolt 181 are prepared, and further, the temporary fixing bolt 200 and the pulling bolt 200a are prepared. The temporary fixing bolt 200 and the pulling bolt 200a have the same configuration and dimensions, and the part of the pulling bolt 200a corresponding to the temporary fixing bolt 200 is provided with a reference mark of the same number and a subscript a. Shown. As shown in FIG. 16, the temporary fixing bolt 200 is similar to the above-mentioned bearing bonding bolt 181 and has a hexagonal bolt head 205, a washer portion 206 having a diameter larger than that of the temporary fastening accommodation hole 201, and a shaft portion 207. Is integrally formed, and a male screw having an outer diameter D22 (D22 <D11), which is less than the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining, is engraved on the shaft portion 207. The length under the neck of the shaft portion 207 of the temporary fastening bolt 200 is the same as that of the pressure-supporting joining bolt 181 and a thread is engraved in the same manner. The pulling bolt 200a has a shaft portion 207a in which a male screw having an outer diameter D22a (D22a <D11), which is less than the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining, is engraved.

An example of dimensions and specifications will be described with reference to FIG. The outer diameter D22 of the shaft portion 207 of the temporary fixing bolt 200 of FIG. 16 is φ12 mm, and the inner diameter D12 of the temporary fixing pilot hole 202 for screwing the temporary fixing bolt 200 is φ11.5 mm (D12 < D22). Other dimensions are the same as the pressure joint bolt 181. For example, the under-neck length L207 of the shaft portion 207 of the temporary fastening bolt 200 is the same as the under-neck length L193 of the bearing joint bolt 181, and the threaded portion of the shaft portion 207 has a long male thread. It is engraved over 28 mm (= 16 + 12). The inner diameter D32 of the temporary fastening accommodation hole 201 may have a value of φ15.5 mm, which is equal to the inner diameter D11 of the pilot holes for bearing pressure joining 197 and 198. The temporary fastening bolt 200, the pulling bolt 200a, and their related configurations have the same dimensions, and the corresponding pulling bolt 200a portion of the temporary fastening bolt 200 is subscripted with the same number reference. Shown with a.

An example of dimensions and specifications will be described with reference to FIG. The outer diameter D21 of the shaft portion 193 of the bearing bonding bolt 181 of FIG. 17 is φ16 mm, and the inner diameter D11 of the bearing bonding pilot holes 197 and 198 for screwing the bearing bonding bolt 181 is φ15.5 mm (. D11 <D21). There are two rows of pilot holes for bearing pressure joining 197 and 198 in the direction of the bridge axis perpendicular to the paper surface of FIG. 12, and there are 36 in each row. 110 mm, material carbon steel SWCH. The thickness t150 of the web 150 is 16 mm, and the material structural steel material SM490YA. The thickness t171 of the flange 171 and the rib 172 of the stiffener 156 is 12 mm, the height of the rib 172 is 150 mm, and the material structural steel material SM490YA. The length L193 under the neck of the bearing pressure joining bolt 181 is 33 mm, and the length of the threaded portion 194 in which the thread of the shaft portion 193 is engraved is 28 mm (= 16 + 12), and the thickness of the web 150. It is selected to be greater than or equal to the sum of t150 and the thickness t171 of the flange 171 ((t150 + t171) ≦ L193). The material of the stiffener 156 is the same as or higher than the material of the web 150. In this way, an example of the mechanical strength of seismic retrofitting according to the present invention can be obtained.

In step s2, a pilot hole drilling step for bearing pressure joining of the stiffener 156 is performed on the flange 171 of the stiffener 156 at the manufacturing plant. The plurality of bearing holes 197 of FIG. 17 are spaced from each other in the longitudinal direction of the stiffener 156 at the positions 2p to 16p, 18p, 20p to 35p: 2q to 16q, 18q, 20q to 35q of FIG. In a row, for example, holes are drilled in a steel material using a small magnetic drilling machine that can be magnetically attracted and detached.

Perform a temporary fastening flexible hole drilling step. At positions 1p, 36p: 1q, 36q in FIG. 15 (1) near both ends of the stiffener 156 in the longitudinal direction, the flange 171 of the stiffener 156 has a temporary fastening accommodation hole 201 (for temporary fastening bolt 200). FIG. 16) is drilled. The temporary fastening accommodation hole 201 has an inner diameter D32 (D22 <D32 ≦ D11) that exceeds the outer diameter D22 of the shaft portion 207 of the temporary fastening bolt 200 and is equal to or smaller than the inner diameter D11 of the pilot hole for bearing pressure joining.

Perform the pulling operation hole drilling step. Spacing positions 17p (at position 18p of 1 in this embodiment) for one or more bearing joint pilot holes 197 in FIG. 15 (1) towards the center of the stiffener 156 in the longitudinal direction, At 19p, the flange 171 of the stiffener 156 is drilled with a pulling operation hole 201a, which is a flexible hole for the pulling bolt 200a. The pulling operation hole 201a has an inner diameter D32 (D22a <D32 ≦ D11) that exceeds the outer diameter D22a of the shaft portion 207a of the pulling bolt 200a and is equal to or less than the inner diameter D11 of the pilot hole for bearing pressure joining.

The numbers 1 to 3 in the white circles in FIG. 15 (1) indicate the order of each operation step, and are indicated by adding a subscript b to the numbers in the present specification.
In step s3, a pilot hole drilling step for temporary fastening of the lower chord member 121 (1b in FIG. 15 (1)) is performed. At positions 1p, 36p: 1q, 36q, a temporary fastening flexible hole 201 was used as a guide for a punch in the web 150 of the lower chord member 121, a punch was hit, and a small magnetic drilling machine was used in the punch hole. Drill a pilot hole 202 for temporary fastening. The temporary fastening pilot hole 202 has an inner diameter D12 (D12 <D11) smaller than the inner diameter D11 of the pressure-supporting joint pilot holes 197 and 198. The outer diameter D22 of the shaft portion 207 of the temporary fastening bolt 200 is selected to have a value exceeding the inner diameter D12 of the temporary fastening pilot hole 201 (D12 <D22 <D11).

In step s4, a temporary fastening step (1b in FIG. 15 (1)) is performed. By guiding and inserting the temporary fixing bolt 200 into the temporary fixing accommodation hole 201 of the flange 171 of the stiffener 156 and screwing it into the temporary fixing pilot hole 201, the female screw is formed and stiffened. The flange 171 of the material 156 and the web 150 of the lower chord material 121 are brought into close contact with each other in a temporarily fastened state to suppress skin gaps.

In step s5, a pulling locking hole drilling step (2b in FIG. 15 (1)) is performed. At positions 17p and 19p, a pulling locking hole 202a, which is a pilot hole having an inner diameter D12a (D12a <D11) smaller than the inner diameter D11 of the bearing joint pilot hole 197, is drilled in the web 150 of the lower chord member 121. This step S5 is similar to the temporary fixing pilot hole drilling step of step s3 described above.

The outer diameter D22a of the shaft portion 207a of the pulling bolt 202a is selected to have a value exceeding the inner diameter D12a of the pulling locking hole 202a (D12a <D22a <D11).
In step s6, the pulling step (2b in FIG. 15 (1)) is performed. By guiding and inserting the pulling bolt 200a into the pulling operation hole 201a of the flange 171 of the stiffener 156 and screwing it into the pulling locking hole 202a, the stiffener 156 advances while forming a female screw by itself. The flange 171 and the web 150 of the lower chord member 121 are brought into close contact with each other in a pulled state to suppress skin gaps.

In step s7, a pilot hole drilling step for bearing pressure joining of the lower chord member 121 is performed. The pilot hole 197 for bearing pressure joining of the flange 171 of the stiffener 156 guides the cutting tool of the drill tool, and the pilot hole 198 for bearing pressure joining is drilled in the web 150 of the lower chord member 121 by so-called kneading.

In step s8, a pressure-supporting joining step (3b in FIG. 15 (1), 1b to 7b in FIG. 15 (2), and 1b to 4b in FIG. 15 (3)) is performed between the stiffener 156 and the lower chord member 121. First, at the position 18p shown by 3b in FIG. 15 (1), the pressure-supporting bolt 181 is placed in the pressure-supporting pilot holes 197 and 198 from the flange 171 of the stiffener 156 toward the web 150 of the lower chord member 121. By screwing in, the female threads are formed by themselves and the bearing joint holes 186 and 187 (FIG. 12) are formed, and the flange 171 of the stiffener 156 and the web 150 of the lower chord member 121 are pressure-bonded.

Next, in the order shown by 1b to 7b in FIG. 15 (2), at each position 16p, 16q to 20q, 20p, the pilot hole drilling step for bearing pressure joining of the lower chord member 121 and the step s8 are the same as in step s7. Similarly, the operation including the pressure-supporting joining step of the stiffener 156 and the lower chord member 121 is repeatedly performed to support-bond the flange 171 of the stiffening member 156 and the web 150 of the lower chord member 121.

Further, subsequently, in the order shown by 1b to 4b in FIG. 15 (3), the operation including the pilot hole drilling step for bearing pressure joining and the bearing pressure joining step for each position 15p, 15q, 21q, 21p. Is repeated. When the operation of 4b in FIG. 15 (3) is completed, the bearing contact is performed from the center in the longitudinal direction toward both ends in the same order as described above, for example, in the order of each position 14p, 14q, 22q, 22p. The operation including the combined pilot hole drilling step and the pressure bearing joining step is repeated for each position, repeated up to each position 2p, 2q, 34q, 34p, and further repeated at each position 35p, 35q.

In step s9, a temporary fastening diameter expansion bearing pressure joining step is performed. At positions 1p, 36p: 1q, 36q, the temporary fixing bolt 200 is removed to make the temporary fixing flexible hole 201 and the inner diameter D12 of the temporary fixing prepared hole 202, using a drill tool blade or the like, to make a pilot hole for bearing pressure joining. The diameter was expanded to the inner diameter D11 of 197 and 198, and the flange 171 of the stiffener 156 and the web 150 of the lower chord member 121 were pressure-supported by the pressure-supporting joint bolt 181 in the expanded pressure-bearing joint pilot holes 197 and 198. Join.

In step s10, a pulling and expanding diameter bearing joint step is performed. At positions 17p, 19p, step s10 is similar to step s9. First, the pulling bolt 200a is removed. Next, in one embodiment, if the inner diameter D32a of the pulling operation hole 201a is equal to the inner diameter D11 of the pressure-bearing joint pilot holes 197 and 198 (D32a = D11), it is not necessary to increase the diameter, or In another embodiment, if the inner diameter D32a of the pulling operation hole 201a is less than the inner diameter D11 of the bearing hole 197, 198 (D32a <D11), the inner diameter D11 of the bearing hole 197, 198 Increase the diameter. The inner diameter D12a of the pulling locking hole 202a is expanded to the inner diameter D11 of the pilot holes 197 and 198 for bearing pressure joining (D12a <D11). After that, the flange 171 of the stiffener 156 and the web 150 of the lower chord member 121 are pressure-bonded by the pressure-supporting bolt 181.

FIG. 19 is a flowchart showing a method of constructing a buckling prevention structure on the lower chord member 121 of the lateral truss 110 of the steel bridge 100 in another embodiment of the present invention. FIG. 20 is a side view for explaining an operation sequence for fixing the stiffener 156 to the web 150 of the lower chord member 121 by pressure-bearing joining in each step u1 to u13 of FIG. This embodiment is similar to the previous embodiment.

The construction work shown in FIG. 19 will be described with reference to FIG. 20 and with reference to FIGS. 1-18 as appropriate. The process proceeds from step u1 to step u2 in FIG. 19, and as in step s1 described above, the stiffener 156 and the pressure-supporting joining bolt 181 are prepared, and further, the temporary fastening bolt 200 and the pulling bolt 200a are prepared.

In this step u2, a pilot hole drilling step for bearing pressure joining of the stiffener 156 is performed on the flange 171 of the stiffener 156 at the manufacturing plant. A plurality of pilot holes 197 for bearing pressure joining in FIG. 17 are arranged at positions 2p to 16p, 18p to 35p: 2q to 19q, 21q to 35q in FIG. 20 (3) at intervals in the longitudinal direction of the stiffener 156. For example, a small magnetic drilling machine is used to drill a hole.

Perform a temporary fastening flexible hole drilling step. At the manufacturing plant, the stiffener 156 is temporarily fastened to the flange 171 of the stiffener 156 at positions 1p, 36p: 1q, 36q in FIG. 20 (3) near both ends in the longitudinal direction. The accommodation hole 201 (FIG. 16) is drilled.

Perform the pulling operation hole drilling step. At the manufacturing plant, at two positions 17p and 20q near the center of the stiffener 156 in the longitudinal direction, a pulling operation hole 201a for the pulling bolt 200a is drilled in the flange 171 of the stiffener 156. In the longitudinal direction of the two positions 17p, 20q, one or more positions 18p, 18q: 19p, 19q for the pilot hole for bearing pressure joining 197 are drilled.

In step u3, at the construction site, punches are used on the outer surface of the web 150 at positions 1p, 36p: 1q, 36q near both ends and at positions 17p, 20q near the center in FIG. 20 (3). Make a rule. For this purpose, as shown in FIG. 20 (1), a transparent film sheet on which the positions 1p, 36p: 1q, 36q and 17p, 20q to be marked and the reference line 209 are drawn is placed on the outer surface of the web 150. , With the reference line 209 aligned on the placement reference line for the stiffener 156 pre-drawn on the web 150, the punch is applied to each of these marking positions via the film sheet. Hit with a hammer to form a punch hole.

In step u4, a pilot hole drilling step for temporary fixing of the lower chord member 121 is performed, which is similar to step s3 in FIG. As shown in FIG. 20 (2), at positions 1p, 36p: 1q, and 36q near both ends, a temporary fixing pilot hole 202 is drilled in the punch hole in the web 150 of the lower chord member 121 by using the above-mentioned small drilling machine.

In step u4, a pulling locking hole drilling step similar to step s5 in FIG. 14 described above is also performed. At positions 17p and 20q near the center, a small drilling machine is used to drill a pulling locking hole 202a in the web 150 of the lower chord member 121 and a punch hole in the web 150 of the lower chord member 121.

After performing the pilot hole drilling step for temporary fastening and the locking hole drilling step for pulling, as shown in FIG. 20 (3), the lower chord member 121 is attached to the traction tool 221 such as a chain block (trade name) and the cord 222. By suspending the cord 3 such as a nylon sling by surrounding the lower chord member 121 and the stiffener 156 and tightening the stiffener 156 with a traction tool such as a lever block (trade name). Fixed to the outer surface of the web 150. In this fixed state, the positions 1p, 36p: 1q, 36q and 17p, 20q are aligned with the corresponding temporary fastening flexible holes 201 and pulling operation holes 201a of the stiffener 156.

In step u5, a pulling step similar to step s6 in FIG. 14 described above is performed. As shown in FIG. 20 (4), a pulling jig is prepared and used at positions 17p and 20q near the center. The pulling jig uses the accommodation hole 201a of the flange 171 of the stiffener 156 and the locking hole 202a for pulling the web 150, and the flange 171 of the stiffener 156 is provided on the outer surface of the web 150 with a skin gap. Make close contact so that it does not occur. Instead of the pulling jig, the above-mentioned pulling bolt 200a may be used in the same manner. The pulling jig, the pulling bolt 200a, and the like constitute a pulling means.

In step u6, a temporary fastening step similar to step s4 in FIG. 14 described above is performed. As shown in FIG. 20 (5), at positions 1p, 1q, 36p, and 36q near the end, the temporary fastening bolt 200 is temporarily fastened by inserting the temporary fastening flexible hole 201 of the flange 171 of the stiffener 156. By screwing into the pilot hole 201, the flange 171 of the stiffener 156 and the web 150 of the lower chord member 121 are brought into close contact with each other to be in a temporarily fastened state, and a skin gap is suppressed.
In each of FIGS. 20 (6), (7) and (11) described below, the numbers 1 to 35 in the white circle indicate the order of each operation step, and in the present specification, the numbers are subscripted b. Is attached.

In step u7, as shown in 1b of FIG. 20 (6), at the position near the center 18p, a pilot hole drilling step for bearing pressure joining and a bearing pressure joining step similar to the above-mentioned step s7 of FIG. 14 are performed. Do it. The pilot hole 197 for bearing pressure joining of the flange 171 of the stiffener 156 guides the cutting tool of the drill tool, and the pilot hole 198 for bearing pressure joining is applied to the web 150 of the lower chord member 121 to make a hole, and the stiffener is drilled at the position 18p. A pressure bonding step of 156 and the lower chord member 121 is performed.

In step u8, as shown in 2b to 4b of FIG. 20 (6), the pilot hole drilling step for bearing pressure joining and the bearing pressure joining step of the lower chord member 121 are further performed at the positions 19p, 19q, and 18q near the center.

In step u9, in FIG. 20 (7), after the pressure bonding of 1b to 4b of FIG. 20 (6) described above, 5b to 9b are alternately left and right at each location from the center toward the left and right ends. For each position 20p, 17p, 20q, 17q, 21p, 16p, 21q, 16q, 22p, 22q in the order indicated by, the pilot hole drilling step for bearing joint of the lower chord material 121, and the stiffener 156 and the lower chord material. The operation including the pressure-supporting joining step with 121 is repeatedly performed to support-bond the flange 171 of the stiffener 156 and the web 150 of the lower chord member 121.

While each operation consisting of the pilot hole drilling step for bearing pressure joining and the bearing pressure joining step is repeated for each position, for example, as shown in FIG. 20 (8), at the position 15p, with the flange 171 of the stiffener 156. When there is a skin gap Δ15p (Δ1 <Δ15p) with a predetermined control upper limit value Δ1 (for example, 1 mm) or more between the lower chord material 121 and the web 150, it is adjacent to the end direction (left side in FIG. 20 (8)). At the position 14p, the pilot hole 198 for bearing pressure joining is drilled in the pilot hole drilling step for bearing pressure joining of the lower chord member 121, and the pulling jig or the pulling bolt 200a is used using the pilot holes 197 and 198 for bearing pressure joining. It is used to pull and eliminate skin gaps, after which a bearing bonding step of stiffener 156 and lower chord member 121 is performed at position 15p. In this way, for example, at positions 22p, 15q, 22q, 14q, etc., each operation including the pilot hole drilling step for bearing pressure joining and the bearing pressure joining step alternately left, right, top and bottom from the center toward both ends is shown in FIG. 20. Repeat until the positions 5p, 5q: 32p, and 32q of the same number (for example, 5) set in advance, leaving the end ranges 225 and 226 at the left and right ends in the longitudinal direction shown in (9). The end range 225 and 226 are provided in order to secure a space in which a small drilling machine is magnetically attracted and fixed so that a pilot hole 198 for bearing pressure joining can be drilled in the end range 225 and 226.

In step u10, after performing a pressure-supporting joining step between the stiffener 156 and the lower chord member 121 at positions 5p, 5q to 32p to 32q near the center shown in FIG. 20 (9), the end range 225 at both ends is performed. Remove the temporary fastening bolts 200 at positions 1p, 1q, 36p, and 36q in 226, and the same number (for example, 4) of end ranges 225 and 226 in the longitudinal direction are vertically positioned 1p to 4p, 1q to 4q. : At 33p to 36p and 33q to 36q, the cutting tool of the drill tool is guided by the pilot hole 197 for pressure bonding of the flange 171 of the stiffener 156, and the pilot hole 198 for pressure bonding is applied to the web 150 of the lower chord member 121 and kneaded. Drill a hole.

In step u11, as shown in FIG. 20 (10), when the padding drilling operation of the end range 225 and 226 is completed, for example, at the position 34p or 35p, the flange 171 of the stiffener 156 and the lower chord member 121 When there is a skin gap between the web 150 and the predetermined control upper limit value Δ1 or more, at positions 36p and 36q adjacent to the end direction (right side in FIG. 20 (10)), for pressure bonding of the lower chord member 121. Drill a pilot hole 198 for bearing pressure joining in the pilot hole drilling step, and use a pulling jig or a pulling bolt 200a using the pilot holes 197 and 198 for bearing pressure joining to pull and eliminate the skin gap, and then At positions 36p and 36q, the bearing joint step of the stiffener 156 and the lower chord member 121 is performed. After that, the cord 223 is removed.

In step u12, as shown in FIG. 20 (11), at all positions 1p to 4p and 1q to 4q: 33p to 36p and 33q to 36q in the end range 225 and 226, a pilot hole for pressure bonding is provided to the web 150 of the lower chord member 121. In 197 and 198, a pressure-supporting joining step of the stiffening member 156 and the lower chord member 121 is performed by the pressure-supporting joining bolt 181.

According to the experiment of the present inventor, in one embodiment including the pressure bonding between the flange 171 of the stiffener 156 and the web 150 of the lower chord member 121 by the pressure bonding bolt 181 shown in FIGS. 12 to 18. Regarding the airtightness, by a foam leakage test (JIS Z 2329: 2002), an air pressure equivalent to an altitude of 150 km was applied for 10 seconds in a vacuum box provided with a bearing joint, and the infiltration of air was confirmed using the pressure difference. As a result, it was confirmed that there was no intrusion of air from the periphery of the pressure-supporting joint bolt 181 that was pressure-bonded. For watertightness, according to the waterproof test (JIS C 0920: 2003), a box of test specimens equipped with pressure-supporting joints was installed on the turntable, and 1000 liters / minute of water was applied directly for 3 minutes evenly and directly in the IPX6 test, and 6 atm. The IPX8 test was carried out by immersing in water for 30 minutes under the water pressure of. As a result, it was confirmed that there was no intrusion of water from the periphery of the pressure-supporting joint bolt 181 to the inside. Therefore, the lower chord member 121 does not require a waterproof rust preventive layer on the inner surface of the closed space.

According to the experiment of the present inventor, in one embodiment of FIGS. 1 to 18 described above, the stress range generated in the stiffener 156 is a maximum of 7.6 N / mm ² at the joint position of the bearing joint bolt 181. At one point, it exceeded the fatigue design curve of D grade and confirmed that the fatigue strength was equivalent to C grade (strength grade is according to the road bridge specification).

FIG. 21 is a perspective view of another embodiment of the present invention. This embodiment is similar to that of the previous embodiment, but it should be noted that the stiffeners 156 and 159, which are simply shown, are fixed to the outer surfaces of the webs 150 and 151 of the lower chord member 121. Instead, the stiffeners 213 and 214 are also fixed to the outer surfaces of the flanges 152 and 153. The stiffeners 156, 159, 213, 214 extend along the webs 150, 151 and the flanges 152, 153 in the widthwise center, perpendicular to their bridge axis, perpendicular to the bridge axis.

22 (1) is a simplified cross-sectional view of the lower chord member 121 of FIG. 21. At the time of an earthquake, the compressive load of the arrows 215 and 216 of FIG. 21 acts on the lower chord member 121. Seismic retrofitting webs 150, 151 and flanges 152, 153 have virtual lines 150e, 151e, 152e, between their widthwise ends and the stiffeners 156, 159, 213, 214 shown briefly. As shown by 153e, relatively small out-of-plane buckling deformation is performed, large deformation is avoided, and fracture is prevented.

FIG. 22 (2) is a cross-sectional view of the conventional lower chord member 121. The conventional lower chord member 121 is not provided with the stiffeners 156, 159, 213, and 214 according to the present invention, and has a small load bearing capacity. Therefore, at the time of an earthquake, the webs 150 and 151 and the flanges 152 and 153 as a whole undergo relatively large out-of-plane buckling deformation and rupture as shown by the virtual lines 150f, 151f, 152f and 153f, respectively. There's a problem. The present invention solves this problem with stiffeners 156 and 159, as well as stiffeners 213 and 214.

Aforementioned Figure 21, according to the embodiment of FIG. 22 (1), width-thickness ratio of each web 150 to 153 of the lower chord member 121 Retrofit by stiffener 156,159,213,214 parameter _R R ( The parameter related to the buckling of the plate) is expressed by Equation 1.

FIG. 23 is a diagram showing the relationship between the _{width-thickness ratio parameter RR and the ultimate strength σ cr} / σ _y , which is the load bearing capacity, in the above-described embodiment. Line L1 in FIG. 23 shows a reference load bearing curve in this embodiment. In this embodiment, since the number of panels n can be set to 2, the number of panels n in the conventional lower chord member 121 (FIG. 22 (2)) to which the stiffeners 156, 159, 213, and 214 are not provided is 1. the width-thickness ratio parameter R _R compared to a configuration, it is possible to reduce as leftward white arrow in FIG. 21. Therefore, when σ _cr is the stress degree at the time of buckling, _{it can be seen that the ultimate strength σ cr} / σ _y , which is the load bearing capacity, can be greatly improved as shown by the upward white arrow in FIG.

FIG. 24 is a cross-sectional view of the lower chord member 121 according to still another embodiment of the present invention. This embodiment is similar to the above-described embodiment, but it should be noted that two stiffeners 231, 232, 233, and 234 are fixed to the outer surfaces of the webs 150 and 151 of the lower chord member 121, respectively. Will be done. The stiffeners 155 to 159 and 231 to 234 are fixed at positions where the vertical distance between the upper and lower flanges 152 and 153 is divided into 1/3 at equal intervals. In this embodiment, since the panel number n of width-thickness ratio parameter R _R of each web 150 and 151 can be in 3, can further reduce the width-thickness ratio parameter R _R as compared with the above embodiments, ultimate strength σ _cr / σ _y can be greatly improved.

The stiffeners 155 to 159 and 231 to 234 may have a flange and ribs forming an L-shaped cross section instead of the T-shaped cross section, and are provided only on the webs 150 and 151 of the lower chord member 121. However, it may be provided only on the flanges 152 and 153, or may be provided on the upper chord member 112 or the middle chord member 117 which is a closed cross-section member instead of the lower chord member 121, and a plurality of chord members thereof may be provided. It may be provided on 112, 117, and may be further provided on the outer surface of the closed cross-section member including the above-mentioned or other vertical member, diagonal member, and the like.

Industrial application field

The seismic reinforcement structure of the present invention can be implemented in relation to an existing steel bridge, but can also be implemented in a web, a flange, or the like for a closed cross-section member of a newly erected steel bridge. The present invention can also be carried out in technical fields such as steel structures other than steel bridges.

100 Steel bridge 103 Main tower 104 Truss girder 110 Horizontal truss 121 Lower chord material 145, 148 Diaphragm 150, 151 Web 152, 153 Flange 155-159, 213, 214, 231-234 Steel stiffener 171 Flange 172 Rib 181 Supporting welding Fitting Bolts 186, 187 Supporting Pressure Joining Holes 197, 198 Temporary Fastening Bolts 200a Pulling Bolts 201 Temporary Fastening Flexible Holes 201a Pulling Operation Holes 202 Temporary Fastening Pilot Holes 202a Pulling Locking Holes

Claims (9)

It is a buckling prevention structure for steel closed cross-section members of steel bridges.
The steel closed section member has webs and flanges that form a closed space, with a diaphragm in the closed space.
Includes steel stiffeners and bearing bolts
Steel stiffeners, and a flange and ribs that form a T-shaped cross section or L-shaped cross-section, along the steel closed-section member, the flanges of the steel stiffeners of steel closed-section member web or Placed on the outer surface of the flange, avoiding the position of the diaphragm,
Through the web or flange of the flange and the steel closed-section member of the steel stiffener, in a row at intervals in the longitudinal direction of the steel stiffeners and the steel closed-section member, a plurality Preliminary holes for bearing pressure joining are drilled in advance.
The bearing bearing bolt is a one-side bolt realized by a high-strength bolt, and has a shaft portion on which a male screw having an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the bearing bearing pilot hole is engraved. has, formed into a web or under a pressure bearing joint hole toward the flange of the steel closed-section member from the flange of the steel stiffeners, by being screwed, the willing Bearing joining hole while forming itself an internal thread and, anti-buckling structure of steel closed-section member of steel bridge that the web or flange of the flange and the steel closed-section member of the steel stiffener, characterized in that bearing capacity bonding. When a predetermined longitudinal compressive load is applied to the steel closed cross section member, it exists closer to the end of the row than the bearing bolts that exist near the center of the row among the bolts for bearing pressure joining in the row. The bearing bolt does not pull out from the web or flange bearing hole of the steel closed cross section, and the shaft of the bearing bolt located at least near the end of the row does not break by shearing. The steel closure of the steel bridge according to claim 1, wherein the mechanical strength of the steel stiffener flange, the web or flange of the steel closed cross section member, and the bearing joint bolt is determined. Anti-shake structure for cross-section members. The buckling prevention structure for a steel closed cross section member of a steel bridge according to claim 1 or 2, wherein the steel closed cross section member is a horizontal truss chord member of a truss girder of a cable-stayed bridge. The horizontal truss chord material is a lower chord material,
The buckling prevention structure for a steel closed cross-section member of a steel bridge according to claim 3, wherein the stiffening range of the steel stiffener is selected between the diaphragms near the main tower. It is a construction method of a buckling prevention structure for a steel closed cross-section member of a steel bridge.
The steel closed section member has webs and flanges that form a closed space and has a diaphragm in the closed space.
Prepare steel stiffeners and bolts for bearing pressure joints,
The steel stiffener has a flange and a rib forming a T-shaped cross section or an L-shaped cross section, and the flange of the steel stiffener has a plurality of pilot holes for bearing pressure joining in the flange of the steel stiffener. Perform a pilot hole drilling step for bearing pressure joining of steel stiffeners that drill holes in rows at intervals in the longitudinal direction.
The flange of the steel stiffener, avoiding the position of the diaphragm on the outer surface of the web or flange of the steel closed-section member along the steel closed-section member disposed,
A pilot hole for pressure-bearing joining of a flange of a steel stiffener guides the cutting tool of a drill tool to drill a pilot hole for pressure-bearing joining in the web or flange of a steel closed-section member. Perform the combined pilot hole drilling step,
The bearing bearing bolt is a one-side bolt realized by a high-strength bolt, and has a shaft portion on which a male screw having an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the bearing bearing pilot hole is engraved. Have and
By screwing the bearing bearing bolt from the steel stiffener flange toward the web or flange of the steel closed cross section member into the bearing bearing pilot hole, the female screw is formed and the bearing bearing hole is advanced. forming a, and characterized by performing Bearing bonding step between the steel stiffeners and the steel closed section member for bearing capacity joining the web or flange of the flange and the steel closed-section member of the steel stiffener Construction method of buckling prevention structure for steel closed cross section members of steel bridges. Prepare a temporary fastening bolt having a shaft portion on which a male screw having an outer diameter D22 (D22 <D11), which is less than the inner diameter D11 of the pilot hole for bearing pressure joining, is engraved.
The flange of the steel stiffeners in the longitudinal direction both end portions near the steel stiffener performs pinning flexibility hole boring step of boring the pinning flexibility hole for the preliminary fixing bolt, the temporary The fastening accommodation hole has an inner diameter D32 equal to the inner diameter D11 of the pilot hole for bearing pressure joining.
The web or flange of the steel closed-section member, the hole under a preliminary fixing of the steel closed-section member which drilling under a temporary fixing hole having an inner diameter less than the inner diameter D11 of the hole under a Bearing junction D12 (D12 <D11) Perform the drilling step,
The outer diameter D22 of the shaft portion of the temporary fastening bolt is selected to have a value exceeding the inner diameter D12 of the temporary fastening pilot hole (D12 <D22 <D11).
By inserting the temporary fastening bolt into the temporary fastening pilot hole by inserting the temporary fastening flexible hole of the flange of the steel stiffener and screwing it into the temporary fastening pilot hole, the steel stiffener advances while forming a female screw by itself. Perform a temporary fastening step to temporarily fasten the flange and the web or flange of the steel closed cross-section member in close contact with each other.
In this temporarily fastened state, performs the bearing capacity bonding step between the bearing capacity pilot hole drilling step for joining, and the steel stiffeners and the steel closed-section member of the steel closed section member,
Thereafter, the inner diameter D12 of the temporary fastening under holes to remove the temporary fastening bolt is enlarged in inner diameter D11 of the hole under a pressure bearing joint, the bearing capacity joining bolts, flanges and steel closed-section member of the steel stiffener The method for constructing a buckling prevention structure for a steel closed cross-section member of a steel bridge according to claim 5, wherein a temporary fastening expansion diameter bearing jointing step of bearing-bonding the web or flange of the steel bridge is performed. Prepare a means of attraction,
Performs drawn for operation hole boring step of boring the operation hole for attracting for means for attracting the flange steel stiffeners in the longitudinal direction close to the center of the steel stiffeners,
Before performing the pilot hole drilling step for pressure-bearing joining of the steel closed cross-section member in the temporary fastening state by the temporary fastening step,
The web or flange of the steel closed-section member, engaging a drawn steel closed-section member to drilling the drawn for locking hole has an inner diameter less than the inner diameter D11 of the hole under a Bearing junction D12a (D12a <D11) Tomeana Perform the drilling step,
The drawn-along means, in relation to the steel stiffener flange attracted manipulation hole and attracted a locking hole of the, by the operation from the side of attraction for operation hole, the flange and made of steel of the steel stiffener Perform the pulling step to bring the web or flange of the closed cross-section member into close contact with the web or flange.
In this pulled state, performs the bearing capacity bonding step between the bearing capacity pilot hole drilling step for joining, and the steel stiffeners and the steel closed-section member of the steel closed section member,
After that, the pulling means is removed by an operation from the side of the pulling operation hole, and the inner diameter D32a of the pulling operation hole and the inner diameter D12a of the pulling locking hole are expanded to the inner diameter D11 of the pilot hole for bearing pressure joining. , by Bearing joint bolt, according to claim 6, characterized by performing enlarged Bearing bonding step attracted to bearing capacity joining the web or flange of the flange and the steel closed-section member of the steel stiffener Construction method of buckling prevention structure for steel closed cross section members of steel bridges. The pulling means is a pulling bolt having a shaft portion on which a male screw having an outer diameter D22a (D22a <D11), which is less than the inner diameter D11 of the pilot hole for bearing pressure joining, is engraved.
The drawn for operation hole drilling step, and drilling the drawn for operation hole for the bolt attracted to the flange of the steel stiffeners in the longitudinal direction close to the center of the steel stiffeners,
In the locking hole drilling step for pulling steel closed cross-section members,
A pulling locking hole having an inner diameter D12a (D12a <D11) smaller than the inner diameter D11 of the pilot hole for bearing pressure joining is drilled in the web or flange of the steel closed cross-section member.
The outer diameter D22a of the shaft portion of the pulling bolt is selected to have a value exceeding the inner diameter D12a of the pulling locking hole (D12a <D22a <D11).
The drawn step, the drawn bolt, is inserted a flange drawn for operation hole of the steel stiffeners, to attract a locking hole, by screwing, steel stiffening proceeds while forming itself an internal thread The flange of the material and the web or flange of the steel closed cross-section member are brought into close contact with each other.
The buckling of a steel closed cross-section member of a steel bridge according to claim 7, wherein the pulling bolt is removed by an operation from the side of the pulling operation hole in the pulling diameter expansion bearing pressure joining step. Construction method of prevention structure. The steel closed section member of a steel bridge has webs and flanges that form a closed space, with a diaphragm in the closed space.
Includes steel stiffeners and bearing bolts
Steel stiffeners, and a flange and ribs that form a T-shaped cross section or L-shaped cross-section, along the steel closed-section member, the flanges of the steel stiffeners of steel closed-section member web or Placed on the outer surface of the flange, avoiding the position of the diaphragm,
Through the web or flange of the flange and the steel closed-section member of the steel stiffener, in rows spaced an equal interval in the longitudinal direction of the steel stiffeners and the steel closed section member, Preliminary holes for bearing pressure joining having the same structure are drilled in advance.
Each of the plurality of bearing bearing bolts has the same structure and is a one-side bolt realized by a high-strength bolt, and has an outer diameter D21 (D11 <D21) exceeding the inner diameter D11 of the pilot hole for bearing pressure joining. has a shaft portion which screw is engraved, the web or under a pressure bearing joint hole toward the flange of the steel closed-section member from the flange of the steel stiffeners, by being screwed, to form their own internal threads while forming a bearing capacity junction hole advances, and a web or flange of the flange and the steel closed-section member of the steel stiffener and Bearing junction,
Mechanical strength of steel stiffener flanges and webs or flanges of steel closed section members, as well as bearing bolts.
When a predetermined longitudinal compressive load is applied to the steel closed cross section member, it exists closer to the end of the row than the bearing bolts that exist near the center of the row among the bolts for bearing pressure joining in the row. The bearing bolt does not pull out from the web or flange bearing hole of the steel closed cross section, and the shaft of the bearing bolt located at least near the end of the row does not break by shearing. As described above, a method for designing a buckling prevention structure for a steel closed cross section member of a steel bridge, which is characterized by being defined.

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