JPS63114705A - Method for dispersing horizontal reaction force of continuous beam structure - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a horizontal reaction force dispersion method for a continuous girder structure such as a continuous girder bridge having a large number of continuous substructures and a prestressed concrete superstructure. It is something.

(Prior art) In a continuous girder structure having a large number of piers, that is, a substructure, such as a prestressed concrete continuous girder bridge,
If the horizontal force during an earthquake in the direction of the bridge axis is received by only one substructure as a fixed fulcrum, the design will be difficult because a large horizontal force will be concentrated only at that point, and if it is fixed at multiple points, The rigidity of the substructure generates internal stress due to displacement due to temperature, drying shrinkage, creep, etc., so there are many considerations not only in the design of the piers, i.e., the substructure, but also in the design of the bridge girders, i.e., the superstructure. This will cause problems.

Therefore, as a conventional means of solving this type of problem, the above-mentioned internal stress can be alleviated by making the connection between the upper structure and the lower structure flexible in the bridge axis direction. Horizontal forces are also supported by distributing them to each substructure.

One method for this is to use natural rubber bearings and utilize shear deformation due to prestress, but this method involves baking steel onto the top and bottom surfaces of natural rubber and fixing them to the upper and lower structures, respectively. Not only is the construction cost high, but since rubber shear springs are used to disperse the horizontal reaction force, the amount of movement during an earthquake is large, so large expansion joints are required, and further Since the structure is deformed even when the bearing is bent, problems such as twisting of the bearing also occur.

Another method that uses a viscous stopper is to form the above-mentioned flexible bond by the effect of the viscous material, but since the viscous mechanism is provided within the lower structure, elastic deformation due to prestress of the upper structure is possible. The amount of deformation due to temperature, creep, drying shrinkage, and earthquake deformation must all be considered before setting, so the amount of deformation becomes a large value, and therefore a large mechanism is required.

[Purpose of the invention]

The present invention solves the above-mentioned conventional problems, makes it possible to ignore the amount of horizontal movement due to prestress in a continuous girder structure made of prestressed concrete having a large number of continuous substructures, and allows the horizontal deflection of the superstructure of this continuous girder structure to be ignored. It is an object of the present invention to provide a method for distributing horizontal reaction force of a continuous girder structure that can evenly distribute force to each substructure.

[Structure of the invention]

In order to achieve the above object, the horizontal reaction force dispersion method for continuous girder structures of the present invention is applied to the upper part of the anchor par whose lower part is fixed to the lower structure while applying prestress to the prestressed concrete superstructure. It is characterized by placing concrete after positioning within the superstructure, and is also characterized by the use of an anchor par that performs positioning within the superstructure while prestressing the prestressed concrete superstructure. The upper part is set in the cap with an elastic body interposed in the transverse direction of the upper part.

〔Example〕

The present invention will be described in detail below with reference to the drawings. Figure 1 shows the continuity between the upper structure and the lower structure of a prestressed concrete continuous girder bridge that applies the horizontal reaction force dispersion method for continuous girder structures of the present invention. Fig. 2 is an enlarged front sectional view of Fig. 1, Fig. 3 is an enlarged plan sectional view of the main part of the anchor par in the direction A-A of Fig. Overall side view of the prestressed concrete continuous girder bridge shown in Figure 1.
Figure 5 is an explanatory diagram of the construction sequence of the continuous girder bridge in Figure 4,
Figures 7 and 8 are explanatory drawings for boxing out the upper structure when the anchor bar is set in Figure 1, Figure 6 is a front sectional view thereof, and Figure 7 is a side sectional view of Figure 6. , and FIG. 8 is a plan view of the main part of FIG. 6.

First, in this example, as a continuous girder structure, a continuous girder bridge having a prestressed concrete superstructure 1 and a plurality of continuous substructures 2 is shown as shown in FIG. As shown in Figure 2, there is a slide support 3 that can move freely in the bridge axis direction of the bridge, and this slide support 3 is compressed by the vertical reaction force from the superstructure 1. Only the uke has, and
The structure is such that the force in the direction perpendicular to the horizontal axis is restrained and fixed by a plurality of anchor bars 4 fixed to the lower structure 2.

Next, as shown in FIGS. 1 and 2, the lower structure 1 (3
The lower part of each anchor par 4 is fixed, and the upper part of the anchor par 4 is set in a rectangular cap 6 with an elastic body 5 such as neobrane interposed in the bridge axis direction as shown in FIG. Therefore, the compression spring force of the elastic body 5 interposed between the anchor par 4 and the cap 6 is used to counter deformation due to temperature, creep, and drying shrinkage in the axial direction of this bridge. It is possible to reduce the horizontal reaction force acting on each substructure 2, and by limiting the space such as the gap 7 in the cap 6 provided for each substructure 2 at each fulcrum, it is possible to reduce the horizontal reaction force acting on each substructure 2. Horizontal forces can be distributed to each substructure 2.

Further, the above-mentioned cap 6 is provided in the upper structure 1, and the area around the installation position of the cap 6 in the upper structure 1 is
By cutting out the box 8 as shown in Figures 7 and 8, and leaving the prestressed concrete free from elastic deformation during prestressing,
Since the amount of deformation due to prestress during construction can be ignored, the amount of deformation set in the anchor par 4 after the completion of construction can be reduced.

The above construction order is as shown in Figure 3, with the dimensions determined by considering the amount of deformation due to creep and drying shrinkage, that is, the amount of horizontal movement, for each fulcrum position of each substructure 2. The cap 6 in which the elastic body 5 having a gap 7 consisting of a hole is set at the front and back of the anchor par 4 in the bridge axis direction and the anchor par 4 are set in position using fixing bolts (not shown).1. After fixing the lower part of the anchor par 4 to the substructure 2, concrete is placed up to the upper edge of the cap 6.

This is to prevent the set position of the camp 6 from shifting due to concrete pouring, and to remove the bolt for fixing the cap 6 provided on the upper part of the anchor par 4 for positioning.

Next, after the concrete has hardened, remove the bolts and return the superstructure 1 to a state where it can move freely in the bridge axis direction. Concrete is poured into the remaining part of the box cutout 8 and prestressed. end.

In order to improve the sliding movement of the anchor par 4 and the contact position of the anchor par 4 inside the cap 6, sliding processing such as Teflon 9 is applied to the anchor par 4 as shown in FIG.

Furthermore, the thickness and predeformation amount of the elastic body 5 provided at the fulcrum position of each substructure 2 are determined by calculation taking into consideration in advance the amount of deformation due to creep and drying shrinkage of concrete to be placed, that is, the amount of movement. By doing so, when the construction is completed, the amount of deformation of the elastic body 5 at each fulcrum position can be made the same amount.

Therefore, when a horizontal force is applied during an earthquake, the amount of deformation of the elastic body 5 is the same, so that the horizontal force is evenly distributed to each fulcrum of each substructure 2.

Note that FIGS. 6, 7, and 8 show a box cutout 8 of the upper structure 1 provided for positioning the upper part of the anchor par 4 inside the superstructure 1. 1, and after introducing prestress for all spans, the 8 boxed areas will be filled with concrete.

In addition, Fig. 5 shows the construction order from the first construction to the completion of the sixth construction when the superstructure 1 is constructed separately for the plurality of lower structures 2 of a continuous girder bridge, and is indicated by P. A temporary support 10 is provided in the lower structure 2, and in the sixth stage of construction, concrete is poured at each joint 8 after prestressing.

Next, the operation of the horizontal reaction force dispersion method for a prestressed concrete continuous girder structure of the present invention explained above will be explained. In general, the horizontal reaction force acting on the substructure 2 is:
This is caused by prestress, creep, drying shrinkage, and inertial force during an earthquake, but the method of the present invention takes into account the amount of horizontal movement of the substructure 2 caused by prestress from the beginning at the time of construction. This is to prevent the influence of prestress later, and to deal with the horizontal reaction force due to horizontal movement caused by creep and drying shrinkage that occurs after construction, the elastic body 5 is attached to the anchor par 4.
The caps 6 interposed at the front and rear in the bridge axis direction are attached to the upper structure 1.
By providing it within, the amount of movement associated with the horizontal reaction force in each lower structure 2 is reduced.

In this case, a box cutout 8 for positioning the cap 6 is provided on the upper structure 1 side, and the upper part of the anchor par 4 fixed to the lower structure 2 is projected into the cap 6 through the elastic body 5. Since prestress will be applied to the superstructure 1, the amount of movement due to prestress, that is, the amount of elastic deformation of the horizontal reaction force generated by the movement of the superstructure 1, should be considered for this continuous girder bridge. This would have already been done at the time of construction.

Therefore, the amount of horizontal movement due to remaining creep and drying shrinkage is absorbed by the action of the elastic body 5, which is press-fitted into the cap 6 from which the anchor bar 4 protrudes, with a predetermined gap therebetween. .

〔Effect of the invention〕

As explained above, if the horizontal reaction force dispersion method of the present invention is applied to a continuous girder structure made of prestressed concrete, the amount of horizontal movement due to prestress during construction can be ignored, and the creep in the superstructure after construction can be ignored. This has the effect of being able to alleviate the horizontal reaction force caused by drying shrinkage.

In addition, by applying the method of the present invention, construction costs for the substructure will be reduced, and the amount of movement required for each fulcrum during an earthquake will be reduced, making the design of the substructure easier and safer. There is an effect.

[Brief explanation of the drawing]

Fig. 1 is a side view of a main part cross-section showing the connection between the upper structure and the lower structure in an embodiment of a prestressed concrete continuous girder bridge to which the horizontal reaction force dispersion method for continuous girder structures of the present invention is applied; The figure is an enlarged front sectional view of Fig. 1, Fig. 3 is an enlarged plan sectional view of the main part of the anchor bar in the direction A-A of Fig. 1, and Fig. 4 is the entire prestressed concrete continuous girder bridge of Fig. 1. Side view, Figure 5 is an explanatory diagram of the construction order of the continuous girder bridge in Figure 4, Figures 6, 7, and 8 are explanations of how to box out the superstructure when setting the anchor bar in Figure 1. In the figure,
6 is a plan sectional view thereof, FIG. 7 is a side sectional view of FIG. 6, and FIG. 8 is a plan view of a main part of FIG. 6. ■... Upper structure, 2... Lower structure, 4... Anchor bar, 5... Elastic body, 6... Cap, 8...
Unbox.

Claims (1)

[Claims] 1. With prestress introduced into the prestressed concrete superstructure, the upper part of the anchor bar whose lower part is fixed to the substructure is positioned within the superstructure, and then concrete is poured. Horizontal reaction force distribution method for continuous girder structures. 2. A continuous girder structure in which prestress is introduced into the prestressed concrete superstructure, and the upper part of the anchor bar, which is positioned within the superstructure, is set in the cap with an elastic body interposed in the axial direction of the bridge. horizontal reaction force distribution method.