JPS5941217Y2 - Seismic support structure - Google Patents

Description

[Detailed explanation of the device] This device is used for elevated bridges, etc., and is interposed between an upper structure such as a bridge girder and a lower structure such as a bridge pier, supporting the load of the upper structure and relieving the expansion and contraction movement of the superstructure. Regarding movable bearings, it relates to an earthquake-resistant bearing structure that disperses horizontal force in the direction perpendicular to the bridge axis and restrains movement.

In general, it is known that seismic damage to bridges is largely influenced by the joints of the upper and lower structures, that is, the bearings, among the bridge girders, piers (abutments), and bearings, and especially the bearings and the parts of the upper and lower structures that are in contact with them are affected. Earthquake resistance has been considered.

It is well known that anti-slip is provided for earthquake resistance in the direction perpendicular to the bridge axis (lateral direction), and the present applicant has also previously reported
In Publication No. 48, a center block system was proposed.

In addition, there is a side block system (Japanese Utility Model Publication No. 7383/1983).

However, in these cases, if the installation accuracy of each of the multiple bearings arranged on the pier is improved, when a lateral force is applied, the strength of one of the bearings exceeds that of the block. The problem is that the block is destroyed by the force exerted on it, and the bearings are damaged one after another (so-called individual destruction), which is not an effective seismic countermeasure.

The present invention was developed in view of the above-mentioned circumstances, and is a new invention that effectively counters lateral forces without requiring strict installation accuracy (easy installation) and solves the problems of the conventional technology described above. This provides a suitable support structure.

Therefore, the present invention requires the following configuration.

■Multiple movable supports are arranged on the piers in the direction perpendicular to the bridge axis.

(2) The town movement support consists of an upper shoe, a lower shoe, and a movable member interposed between the upper shoe and the lower shoe.

■An intermediate anchor member is fixed on the pier between adjacent bearings.

(2) A tension member is stretched across the intermediate anchor member and the upper shoe of the movable support.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

So, S2...Sn is a bridge girder G on one pier B
A plurality of movable supports are installed in the direction perpendicular to the bridge axis (lateral direction) in order to movably support the bridge, and each support S may be an upper shoe 1, a lower shoe 2, and a sliding member 3 disposed in between. Become.

In the case of this embodiment, the sliding member 3 is constituted by a sliding plate that is embedded in the recess 2a of the lower shoe and protrudes from the upper surface 2b of the lower shoe, and the upper surface 3a of the sliding plate makes sliding contact with the lower surface 1a of the upper shoe 1. .

When special strength and lubricity are required, the sliding plate is mainly made of high-strength brass castings, and in addition to being filled with solid lubricant as appropriate, the sliding surface is coated with fluorine resin.
The present invention is not limited to the material of the sliding plate.

Further, the sliding member 3 may be a roller rocker, a pendulum, etc. (2) 4 is an intermediate anchor member disposed at an intermediate position between mutually adjacent movable bearings S, and an anchoring portion 41 is placed in the concrete at the top of the pier. It is anchored underground.

42 is a fork for locking a tension member which will be described later, and 43 is a collar.

5 is a tension member that is stretched under constant tension across the upper shoe 1 of the movable support S and the intermediate anchor member 4,
Consists of PC cable or steel rod.

A turnbuckle 6 is interposed in the tension member 4 and adjusts the tension of the tension member 5, but the turnbuckle 6 can be omitted if necessary.

An end fitting 51 is fixed to the end of the tension member 5, and includes two prongs 42 of the intermediate anchor member and two prongs 1 provided on the side of the upper shoe.
1 via a joint pin T so that it can swing freely.

Further, a threaded condom 52 is fixedly attached to the end of the tension member 5 connected to the turnbuckle 6.
The tension of the tension member 5 is adjusted by screwing the threaded portion 52a of the turnbuckle 6 into the female threaded portion of the turnbuckle 6.

8 is an anchor for fixing the upper shoe 1 to the bridge girder G, and 9 is an anchor for fixing the lower shoe 2 to the bridge pier B.

The characteristic configuration of the seismic support structure of the present invention is that the tension member 5
The tension is adjusted and the tension member 4 is stretched across the upper shoe 1 of the adjacent support S and the intermediate anchor member 4 disposed at an intermediate position between the support S. are arranged in a straight line in the direction perpendicular to the bridge axis, so no harmful couple will occur.

Next, the behavior of the support structure of the present invention when the bridge girder G receives an external force in the direction perpendicular to the bridge axis (lateral force direction) will be explained.

Now, when an external force such as an earthquake acts on the bridge girder G in the lateral force direction A (right direction on the paper in Figure 1), the upper shoe 1 fixed to the lower surface of the bridge girder G receives force in the A direction, and the sliding member 3 Try to move the top in direction A.

However, since each upper shoe 1 is connected by a tension member 5 to an intermediate anchor member 4 fixed on a relatively stationary pier B, the tension member 5 on the upper right side cooperates at the same time. It is pulled, receives the tensile force of the tension member 5, and is prevented from moving in the direction A.

In other words, if there are n (≧2) supports S, each upper shoe 1 receives a force equal to n-1 of the external force at the same time, and if n is set sufficiently large, the tension member 5 It can be seen that the resistance stress per bridge gradually decreases and the force that prevents the movement of the bridge girder G increases.

Furthermore, when an external force acts in the direction toward the mouth (toward the left in the first drawing), as described above, the bridge girder G is prevented from moving toward the mouth due to the tensile force of the tension member 5 extending downward to the right. be.

Since the external force caused by seismic motion acts repeatedly in the A direction and the A direction, the tension members 5 stretched in a V shape function alternately.

Furthermore, since the movement between the bridge girder G and the pier B is relative, even if the pier B moves in the lateral direction, the explanation will be similar to the above.

Regarding the influence of the tension member 5 on the movement of the bearing S in the bridge axis direction (vertical direction), the distance t between the measured surface of the bearing S and the intermediate anchor member 4 is the same as that between the upper shoe 1 and the lower shoe 2. relative movement (temperature expansion and contraction, movement during earthquakes, expansion and contraction due to live loads, etc.)
Since it is sufficiently large compared to , the tension member 5 does not hinder movement in the vertical direction.

It functions as a guide for vertical movement.

The present invention is not limited to the configuration of the embodiments described above, and various design changes can be made within the scope of the basic technical idea of the present invention.

That is, when the intermediate anchor member is anchored to the pier when the pier is made of steel, the flange 43 is directly fixed to the upper surface of the pier by welding, and the anchoring portion 41 is not necessary.

Further, instead of only one intermediate anchor member being provided between adjacent supports S, two intermediate anchor members may be provided depending on the support spacing or other load conditions.

In this case, each intermediate anchor member mutually shares the tension of one of the tension members.

Since the seismic support structure of the present invention has the above-described structure and function, it has the following various superior effects compared to conventional structures.

■ It is possible to reliably prevent movement in the direction perpendicular to the bridge axis, which is harmful to the bridge girder, without disturbing the movement in the direction of the bridge axis.

■ In response to sudden impact forces perpendicular to the bridge axis during an earthquake, the tension members are pulled simultaneously and together, so the phenomenon in which the bearings are damaged one after another (individual failure) is not an economical solution for tensile members. can be designed according to

■ There is no need for complicated molding such as a slip stopper or center flock between the upper shoe, lower shoe and sliding member, and the structure is simple, making it easy to mold the bearing.

■ The work becomes easier because the tension of the tension member can be adjusted after installation without requiring particular precision in the installation accuracy of the upper and lower shoes.

■ Since the tension members are stretched in a straight line in the direction perpendicular to the bridge axis, no couple force is generated by the tension members.

■ In case of excessive movement in the axial direction of the bridge, the tensile force of the tension member increases, suppressing the movement, and is effective in preventing the bridge from collapsing.

[Brief explanation of drawings]

The drawing is an example of the seismic support structure of the present invention, and the first
The figure is an overall view as seen from the axial direction of the bridge, and Figure 2 is a partial vertical cross-sectional view showing details. S...Support, 1...Upper shoe, 2...
...Lower shoe, 3...Sliding member, 4...Intermediate anchor member, 5...Tensile member.

Claims (1)

[Scope of utility model registration request] A plurality of movable supports S1 are disposed on the pier B in a direction perpendicular to the bridge axis and are composed of an upper shoe 1, a lower shoe 2, and a sliding member 3 interposed between both the upper shoe 1 and the lower shoe 2. ．． S2・
..., an intermediate anchor member 4 is fixed on the pier B in the middle of each movable support S, and the intermediate anchor member 4 and the upper shoe 1 of the movable support adjacent to the intermediate anchor member An earthquake-resistant support structure characterized in that a tension member 5 is stretched over the entire area.