JP2000352017A - Bridge construction method - Google Patents

Abstract

(57) [PROBLEMS] To construct a steel arch bridge having an arch member configured to resist bending and axial force and reduce the cross-sectional dimension of the arch member to reduce the weight of the steel material. This will reduce the cost of steel girder production at the factory and the cost of steel girder installation at the site, thereby reducing the construction cost. SOLUTION: After completion of merging of an arch member 14 configured to resist bending and axial force, a prestress P is introduced into the arch member 14 to apply a negative bending moment to the arch member 14. The design section force of the arch member 14 can be adjusted so that the positive bending moment and the negative bending moment have the same value (or a value close thereto). As a result, the bending moment value of the design section force is made smaller than in the past, and the section size of the arch member is reduced. At this time, a small gap 16b is left near the one end (right end) of the stiffening girder member 16, and the stiffening girder member 1
By introducing the prestress P before the completion of the merging of No. 6, the resistance of the stiffening girder member 16 is eliminated, and the prestress P can be set to a minimum necessary value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for erection of a steel arch bridge.

[0002]

2. Description of the Related Art Generally, a steel arch bridge has an arch member formed by connecting and merging a plurality of steel girders along an arch axis. The arch member is designed to resist bending and axial force. Many are configured. As shown in FIG. 8, the design section force of the arch member in such a steel arch bridge is such that the positive bending moment M1 ′ is larger than the negative bending moment M2 ′ over the entire length of the arch member 2. . For this reason, conventionally, the cross-sectional dimension of the arch member 2 is
It is determined based on the load state when the positive bending moment M1 'is generated.

[0003]

However, in the arch member whose cross-sectional dimension is determined as described above,
In a load state in which a negative bending moment is generated, the cross-sectional stress is excessive and the cross-sectional dimension is uneconomical. Then, since the weight of the steel material is increased by the amount of the excess cross-sectional stress, there is a problem that a steel girder manufacturing cost at a factory and a steel girder erection cost at a site are required extra.

[0004] The present invention has been made in view of such circumstances, and in the case of constructing a steel arch bridge having an arch member configured to resist bending and axial force, It is an object of the present invention to provide a bridge erection method capable of reducing erection cost.

[0005]

SUMMARY OF THE INVENTION The present invention achieves the above object by introducing a predetermined prestress in a erection step.

That is, a bridge erection method according to the present invention is a method for erection of a steel arch bridge having an arch member configured to resist bending and axial force. A prestress is introduced into the arch member to apply a negative bending moment to the arch member.

[0007] The concrete structure of the "steel arch bridge" is not particularly limited as long as the arch member is configured to resist bending and axial force.
Various arch types such as arch bridges, tide arch bridges, and rose bridges can be adopted, and bridge structures of upper, middle and lower roads may be used, and both static and indeterminate structures may be used. Good.

The specific method for "introducing prestress" is not particularly limited as long as it can impart a negative bending moment to the arch member. An economical method may be appropriately selected according to the construction situation in consideration of the shape and proof stress, the gap between the point of action between the arch fulcrum and the substructure, workability, and the like.

[0009]

As described above, in the bridge erection method according to the present invention, the prestress is introduced into the arch member after the completion of the merging of the arch member configured to resist bending and axial force. Since a negative bending moment is applied to the arch member, the design section force of the arch member is set so that the positive bending moment and the negative bending moment have the same value (or a value close thereto). Can be adjusted. For this reason, the bending moment value of the design section force can be reduced to a value smaller than that of the related art. As a result, the cross-sectional dimension of the arch member can be reduced, so that the weight of the steel material can be reduced accordingly, thereby reducing the cost of steel girder production at the factory and the cost of erection of the steel girder at the site. it can.

Therefore, according to the present invention, when constructing a steel arch bridge having an arch member configured to resist bending and axial force, it is possible to reduce the construction cost.

In many cases, steel arch bridges have a stiffening girder member in addition to the arch member. However, when such a steel arch bridge is erected, it is necessary to complete the merging of the stiffening girder members. In this case, a large prestress force is required because the stiffening girder member resists when the prestress is introduced into the arch member. Therefore, in such a case, it is effective to introduce prestress into the arch member before the merging of the stiffening girder members is completed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment of the present invention will be described.

FIG. 1 is a view showing a steel arch bridge 10 to be subjected to a bridge erection method according to the present embodiment.

As shown in the figure, this arch bridge 10 is a Rose bridge constructed by a direct suspension construction method between a pair of abutments 12 constructed on the ground surface on both sides of the bridge construction position, and includes an arch member. 14, a stiffening girder member 16 for connecting both ends of the arch member 14, a plurality of vertical members 18 for connecting the arch member 14 and the stiffening girder member 16, and both ends of the stiffening girder member 16. The abutment 12 includes a pair of bearings 20 that are supported at the fulcrum corners 12a. FIG. 1 shows the state of the arch bridge 10 immediately after the merging of the stiffening girder members 16 is completed.

The stiffening girder member 16 of the arch bridge 10
A merging joint 22 is attached to a portion near one end (right end). The joining of the stiffening girder members 16 is completed by attaching the merging joint 22 to the stiffening girder member 16.

FIG. 2 is a view showing a process of erection of the arch bridge 10.

First, as shown in FIG. 1 (a), a pair of steel towers 102 are built on both sides of the bridge erection position.
02, a main cable 108 in which a plurality of hanger ropes 104 and receiving beams 106 are suspended at predetermined intervals,
A carrier 110 extends over a track cable 112 movably mounted, and a backstay cable 116 connected to an adjustment facility 114 is installed behind each tower 102.

The stiffening girder member 16 is mounted on the carrier 110.
The steel girder 16a is suspended and moved to a predetermined position, and the steel girder 16a is sequentially placed on the receiving beam 106 and connected to each other, whereby the stiffening girder member 16 is erected. However, a steel girder 16 is provided near the one end (right end) of the stiffening girder member 16.
In this case, a slight gap 16b is left without connecting a, thereby maintaining the stiffening girder member 16 in an uncompleted state.

Subsequently, as shown in FIG. 2B, after a plurality of vertical members 18 are erected at predetermined intervals on the stiffening girder member 16, the steel girder 1 for the arch member 14 is mounted on the carrier 110.
4a is suspended and moved to a predetermined position.
Are sequentially connected and merged along the arch axis to construct the arch member 14.

Next, as shown in FIG. 2C, a hydraulic jack 118 is provided between one end (right end) of the arch member 14 having been merged and the vertical wall of the fulcrum corner 12a of the abutment 12.
The horizontal reaction force mount 120 is interposed between the other end (left end) of the arch member 14 and the vertical wall of the fulcrum corner 12a of the abutment 12. Then, in this state, the hydraulic jack 118 is driven to introduce the prestress P in the direction of the arrow shown in the figure to the arch member 14.

Since the arch fulcrum interval is narrowed by the introduction of the prestress P, a negative bending moment is applied to the arch member 14 so as to cause the arch member 14 to bend and deform as shown by a broken line in FIG. At the time of the introduction of the prestress P, a slight gap 16b is still left in a portion near one end of the stiffening girder member 16, so that the stiffening girder member 16 resists when the prestress P is introduced. There is no.

FIG. 4A, which is a detailed view of the portion IV in FIG. 2C.
As shown in (1), a plurality of bolt insertion holes 16c are formed in advance in portions near both sides of the gap 16b in the stiffening girder member 16. After the prestress P is introduced into the arch member 14, the joint 22 having a plurality of bolt insertion holes 22a is brought into contact with the stiffening girder member 16 so as to straddle the gap 16b. As shown in (b), the bolt 24 is inserted into each of the bolt insertion holes 22a and 16c, and the bolt 24 is tightened and fixed with a nut, thereby completing the joining of the stiffening girder members 16.

After the joining of the stiffening girder members 16 is completed, the hydraulic jack 118 and the horizontal reaction force gantry 120 are removed. Then, the weight of the arch bridge 10 is supported by the main cable 10.
8 to the bearing 20 of the arch bridge 10 and then
The direct hanging facilities such as the main cable 108 and the truck cable 112 are dismantled and removed.

FIG. 5 is a diagram showing the effect of the introduction of prestress P.

As shown in FIG.
, The arch member 14 has a negative bending moment M as shown in FIG.
Since p is given, the design sectional force of the arch member 14 is set so that the positive bending moment M1 and the negative bending moment M2 have the same value (or a value close thereto) as shown in FIG. Can be adjusted.

For this reason, the bending moment value of the design sectional force can be made smaller than the conventional value (positive bending moment M1 '). As a result, the cross-sectional dimension of the arch member 14 can be reduced, so that the weight of the steel material can be reduced correspondingly, thereby reducing the cost of steel girder production at the factory and the cost of erection of the steel girder at the site. Can be.

Therefore, according to the present embodiment, when the steel arch bridge 10 having the arch member 14 configured to resist bending and axial force is installed,
The construction cost can be reduced.

Moreover, in the present embodiment, the prestress is introduced into the arch member 14 before the stiffening girder member 16 is completely merged. 16 does not resist, and therefore, the prestress P can be set to the minimum necessary value.

In this embodiment, the prestress P is applied to the arch member 14 using the hydraulic jack 118.
However, it is also possible to introduce prestress by other methods.

For example, as shown in FIG. 6A, a plurality of pairs of anchor brackets 122 are installed on both sides of the gap 16b in the stiffening girder member 16, and a tension cable 124 is stretched over each pair of anchor brackets 122. The prestress P may be introduced into the arch member 14 by applying a predetermined tension to each of the tension cables 124.
Even in this case, with the prestress P introduced, the stiffening girder member 1 is attached by attaching the joint 22.
6 are completed, and then, as shown in FIG.
Should be removed.

Next, a second embodiment of the present invention will be described.

FIG. 7 is a construction process diagram showing a bridge construction method according to this embodiment.

As shown in FIG. 3C, the arch bridge 30 to which the bridge erection method according to the present embodiment is applied is an upper road type two-hinge arch bridge, which is constructed on the ground surface on both sides of the bridge erection position. An arch member 34 erected by a method of oblique suspension erection between the pair of foundations 32A, and a stiffening girder member 36 erected between a pair of abutments 32B constructed on both sides of the pair of foundations 32A. A plurality of vertical members 38 connecting the arch member 34 and the stiffening girder member 36;
A pair of bearings 4 for supporting both ends of the base on both bases 32A
0 is provided. FIG. 7 shows the stiffening girder member 3.
6 shows the state of the arch bridge 30 immediately after the merger of No. 6 is completed.

In the bridge erection method according to this embodiment, first, as shown in FIG. 1A, a pair of steel towers 302 are built on both sides of the bridge erection position, and the carrier 304 moves between the two steel towers 302. A track cable 306 that is attached as possible is stretched, and a backstay cable 308 is stretched behind each tower 302.

From the arch fulcrum on both sides to the center between the arch fulcrum, the erection of the steel girder 34a and the installation of the oblique suspension cable 310 are repeated, and the last steel girder 34a
Is moved to the center between the arch fulcrums by the carrier 304 to join the arch members 34 together.

Next, as shown in FIG. 3B, a tied cable 312 is stretched between both ends of the arch member 34.
By applying tension to the tied cable 312, a prestress P in the direction indicated by an arrow is introduced into the arch member 34, and a negative bending moment is applied to the arch member 34. Then, in a state where the prestress P is introduced, the connection position between the two support portions 40 of the arch member 34 and the respective foundations 32A is determined, and then the tide cable 312 is removed.

Next, as shown in FIG. 3C, a plurality of vertical members 38 are installed at predetermined intervals on the arch member 34, and then a stiffening girder member 36 is installed. Then, the support of the weight of the arch bridge 30 is transferred from the oblique suspension cable 310 to the support portion 40 of the arch bridge 30, and thereafter, the direct suspension facilities such as the oblique suspension cable 310 and the track cable 306 are dismantled and removed.

Also in the present embodiment, after the merging of the arch members 34 is completed, a prestress P is introduced into the arch members 34 to apply a negative bending moment thereto. The sectional force can be adjusted so that the positive bending moment and the negative bending moment have the same value (or a value close thereto).

Therefore, also in this embodiment, the first
As in the embodiment, when the steel arch bridge 30 having the arch member 34 configured to resist bending and axial force is erected, the construction cost can be reduced.

Further, in the present embodiment, the prestress P is introduced immediately after the merging of the arch members 34, and thereafter,
Since the vertical member 38 and the stiffening girder member 36 are erected, the stiffening girder member 36 does not resist when the prestress P is introduced. Can be set to a value.

[Brief description of the drawings]

FIG. 1 is a view showing a steel arch bridge which is a target of a bridge erection method according to a first embodiment of the present invention.

FIG. 2 is a construction process diagram showing a bridge construction method according to the first embodiment.

FIG. 3 is a diagram showing a state of bending deformation of an arch member due to introduction of prestress.

FIG. 4 is a detailed view (a) of an IV section in FIG. 2 (c) and a related view (b).

FIG. 5 is a diagram showing the effect of the introduction of prestress.

FIG. 6 is a view similar to FIG. 4, showing a modification of the first embodiment;

FIG. 7 is a construction process diagram showing a bridge construction method according to a second embodiment of the present invention.

FIG. 8 is a view similar to FIG. 5, showing a conventional example.

[Explanation of symbols]

10, 30 Steel arch bridge 12, 32B Abutment 12a Fulcrum corner 14, 34 Arch member 14a, 16a, 34a Steel girder 16, 36 Stiffening girder member 16b Gap 16c, 22a Bolt insertion hole 18, 38 Vertical member 20, 40 Bearing 22 Joining Joint 24 Bolt 32A Foundation 102, 302 Steel Tower 104 Hanger Rope 106 Receiving Beam 108 Main Cable 110, 304 Carrier 112, 306 Track Cable 114 Adjustment Equipment 116, 308 Backstay Cable 118 Hydraulic Jack 120 Horizontal Reaction Force Base 122 Anchor Bracket 124 Tension cable 310 Oblique suspension cable 312 Tide cable M1 Positive bending moment of design section force M2 Negative bending moment of design section force Mp Negative bending moment applied by introduction of prestress P pre-stress

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Oiso 4-13, Arakicho, Shinjuku-ku, Tokyo Sumitomo Construction Co., Ltd. (72) Inventor Harushi Nakamura 13-14 Arakicho, Shinjuku-ku, Tokyo 4 Sumitomo Construction Co., Ltd. In-house (72) Inventor Yowa Hoashi 13-4 Arakicho, Shinjuku-ku, Tokyo Sumitomo Construction Co., Ltd. (72) Inventor Motofumi Saito 4-13 Arakicho, Shinjuku-ku, Tokyo 4 Sumitomo Construction Co., Ltd. (72) Inventor Hiroshi Mashiko 13-4 Arakicho, Shinjuku-ku, Tokyo Sumitomo Construction F-term (reference) 2D059 AA06 BB31 CC05

Claims (2)

[Claims] 1. A method of erection of a steel arch bridge having an arch member configured to resist bending and axial force, wherein after the merging of the arch members is completed, prestress is introduced into the arch member. Applying a negative bending moment to the arch member. 2. The steel bridge according to claim 1, wherein the steel arch bridge has a stiffening girder member, and the prestress is introduced before the merging of the stiffening girder member is completed. Bridge construction method.