JP2018035508A - Construction joint movement restriction device, and bridge pier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To implement an earthquake countermeasure on a concrete bridge pier having a construction joint, without increasing a river blocking rate.SOLUTION: A construction joint movement restriction device 1 includes a recessed part 2 and a rod-like member 3. The recessed part 2 is formed on a side surface of a bridge pier P, across a construction joint J from above to below. The rod-like member 3 is housed inside the recessed part 2, across the construction joint J from above to below. A base end side of the rod-like member 3 is fixed in the recessed part 2 below the construction joint J. A tip end side of the rod-like member 3 is inside the recessed part 2 above the construction joint J, and is separated from an inner wall surface 21 of the recessed part 2. The configuration restricts movement of portions of the bridge pier P above and below the construction joint J within a certain range, at a time of an earthquake.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a joint movement restriction device provided on a concrete pier having a joint and a bridge pier having the joint movement restriction device.

  When a concrete pier (concrete pier) is cast by placing concrete in a plurality of times during construction, a joint will occur. In the case of piers, concrete is cast in order from the bottom, so the joints are horizontal. The joint is a weak point against earthquake shaking. In particular, in an unreinforced bridge pier without a reinforcing bar, the upper side of the joint is moved relative to the lower side during an earthquake, and horizontal displacement or rocking may occur.

  As a seismic reinforcement method for unreinforced piers, a method of winding a band-like member or attaching a connecting steel to a position extending over and under the joint of the pier is known (for example, see Patent Document 1). However, in this method, the pier becomes thicker due to the band-shaped member and the connecting steel, and the river inhibition rate (total width of the pier in the direction of the bridge axis / river width) increases. It may be difficult.

JP 2008-69601 A

  This invention solves the said problem, and aims at taking an earthquake countermeasure, without increasing a river obstruction rate to the concrete pier which has a joint joint.

  The joint movement restriction device of the present invention is a device provided on a concrete pier having a joint, and includes a recess formed on a side surface of the pier over the top and bottom of the joint, and inside the recess over the top and bottom of the joint. A proximal end side of the rod-shaped member is fixed in one of the recesses on the lower side and the upper side of the joint, and a distal end side of the rod-shaped member is below the joint And it is in the other recessed part of the upper side, and is spaced apart from the inner wall face of the recessed part.

  In the seam movement restricting device, a U-shaped member is embedded in the pier so as to partially surround the base end side of the rod-shaped member in the recess, and the base end side of the rod-shaped member is It is preferable that the recess is filled with a filler so as to be fixed in the recess.

  In this seam movement restricting device, it is preferable that the distal end side of the rod-shaped member has a shock absorbing material around it for absorbing an impact.

  In this joint movement restricting device, the distal end side of the rod-shaped member has a spacing material softer than the cushioning material around the cushioning material, and the filling material is filled in a recess around the spacing material. It is preferable.

  In this seam movement restriction device, it is preferable that the filling material is filled in the recess so that the surface of the pier has the same shape as before forming the recess.

  The pier of the present invention is a concrete pier having a joint, and is provided with the joint movement restriction device.

  In the bridge pier of the present invention, it is preferable that a peeling prevention work for preventing the concrete from peeling off is provided below the joint.

  In the bridge pier of the present invention, the peeling prevention work is preferably an anchor bolt driven inward from the surface of the pier.

  In the bridge pier of the present invention, it is preferable that the strip pierce further includes a strip-shaped steel plate attached to the surface of the pier, and the steel plate is attached only to a surface visible from the direction perpendicular to the bridge axis.

  In the bridge pier of the present invention, the peeling prevention work may be a resin coated in a band shape around the lower part of the joint.

  According to the joint movement restricting device of the present invention, the base end side of the rod-shaped member is fixed in the recess on one side from the joint, and the tip side is in the recess on the other side from the joint, and the recess Because it is separated from the inner wall of the bridge, movement to the other side of the pier joint is limited within a certain range in the event of an earthquake, allowing a certain amount of rocking and horizontal displacement and preventing excessive movement be able to. Since the rod-shaped member is accommodated in the recess, the river inhibition rate is not increased.

The side view of the bridge pier which has the joint movement restriction | limiting apparatus concerning the 1st Embodiment of this invention. The front view of the pier which has the same apparatus. Sectional drawing of the apparatus in the vertical cut surface parallel to a bridge axis direction. Sectional drawing of the same apparatus in the AA of FIG. Sectional drawing of the same apparatus in the BB line of FIG. The side view which shows peeling of the concrete after vibration in the test body which simulated the pier. The side view of the pier which concerns on the 2nd Embodiment of this invention. Sectional drawing of the same pier in the CC line of FIG. The side view of the pier which concerns on the 3rd Embodiment of this invention. Sectional drawing of the same pier in the DD line of FIG. The side view of the pier which concerns on the 4th Embodiment of this invention.

(First embodiment)
A seam movement restriction device and a bridge pier having the device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view of the bridge pier P viewed from the bridge axis direction. FIG. 2 is a view of the bridge pier P viewed from a direction perpendicular to the bridge axis, and the left-right direction of FIG. As shown in these drawings, the pier P is a concrete pier, has a joint J, and includes a joint movement restriction device 1. The pier P is a structure that supports the bridge girder G, and is an unreinforced pier in this embodiment. In the present embodiment, the bridge pier P is provided with a plurality of joint movement restriction devices 1.

  FIG. 3 is a cross-sectional view of the joint movement restriction device 1 on a vertical plane parallel to the bridge axis direction. The joint movement restriction device 1 includes a recess 2 and a rod-like member 3. The recess 2 is formed on the side surface of the pier P over the top and bottom of the joint J. The rod-shaped member 3 is accommodated in the recess 2 over the top and bottom of the joint J. The proximal end side of the rod-shaped member 3 is fixed in the recess 2 below the joint J. The distal end side of the rod-shaped member 3 is in the recess 2 above the joint J and is separated from the inner wall surface 21 of the recess 2. Note that the filler filled in the recess 2 is not shown in FIG.

  FIG. 4 is a cross-sectional view of the base end side of the seam movement restriction device 1, that is, the lower side from the seam J, cut along a horizontal plane. In the recess 2, the U-shaped member 4 is embedded in the pier P so as to partially surround the periphery of the base end side of the rod-shaped member 3. The base end side of the rod-shaped member 3 is fixed in the recess 2 by filling the recess 2 with the filler 22.

  FIG. 5 is a cross-sectional view of the front end side of the joint connection restriction device 1, that is, the upper side from the joint J, cut along a horizontal plane. The distal end side of the rod-shaped member 3 has a buffer material 5 that absorbs an impact around it.

  The distal end side of the rod-shaped member 3 has a spacing material 6 that is softer than the buffer material around the buffer material 5. Then, the filling material 22 is filled in the recess 2 around the spacing material 6.

  The filler 22 is filled into the recess 2 so that the surface of the pier P has the same shape as before the recess 2 is formed.

  Each structure of the joint movement restriction device 1 in this embodiment will be described in further detail. The recess 2 is formed by drilling the pier P by a core boring method (see FIG. 3). The rod-shaped member 3 is a steel rod, and its axis is substantially vertical. The U-shaped member 4 is a U-shaped anchor bolt and functions as a reinforcing bar that reinforces the fixation of the rod-shaped member 3. The rod-shaped member 3 is surrounded on three sides by the U-shaped member 4 in plan view. The buffer material 5 is made of hard rubber or the like, and alleviates an impact when the rod-like member 3 is displaced and collides with a surrounding hard structure. The spacing material 6 is a foam joint material. The filler 22 is a fiber reinforced mortar and hardens after filling. After providing the rod-shaped member 3, the U-shaped member 4, etc. in the recessed part 2, the recessed part 2 is backfilled with the filler 22 (refer FIG. 4, FIG. 5). A filler 22 is filled between the buffer material 5 and the inner wall surface 21 of the recess 2.

  As described above, according to the joint movement restriction device 1 according to the present embodiment, the proximal end side of the rod-like member 3 is fixed in the recess 2 below the joint J, and the distal end side is in the recess 2. Since it is separated from the inner wall surface 21 of the recess 2, the movement of the pier P to the lower side above the joint J of the bridge pier P is limited within a certain range in the event of an earthquake, and allows a certain degree of locking and horizontal displacement. , Can prevent excessive movement. By allowing the locking at the joint J, the load on the foundation of the pier P is reduced. This improves the safety of the bridge as an earthquake countermeasure and facilitates early recovery. Moreover, since the rod-shaped member 3 is accommodated in the recessed part 2, it does not increase a river inhibition rate.

  Since the U-shaped member 4 is embedded in the pier P so that the bar-shaped member 3 partially surrounds the periphery on the base end side in the recess 2, the fixing to the pier P is reinforced. The U-shaped member 4 prevents the filler 22 from dropping from the recess 2.

  Since the distal end side of the rod-shaped member 3 has the shock absorbing material 5 that absorbs the shock around it, the shock when the rod-shaped member 3 is displaced and collides with the surrounding hard structure is alleviated.

  Since the distal end side of the rod-shaped member 3 has the spacing material 6 softer than the buffer material around the buffer material 5, it can be displaced. That is, the fact that the spacing member 6 is soft means softness that allows the distal end side of the rod-like member 3 to be displaced. Since the filling material 22 is filled in the recess 2 around the spacing material 6, the internal structure of the joint movement restriction device 1 is protected in normal times.

  By filling the concave portion 2 with the filler 22 so that the surface of the pier P has the same shape as before the concave portion 2 is formed, the joint movement restriction device 1 does not affect the flow of water around the pier P. Can be.

  By the way, in the dynamic test simulating the bridge pier described later, when the vibration acceleration of the same size was applied to the specimen a plurality of times, the displacement of the upper part relative to the lower part from the joint J gradually increased as the number of times was increased. As shown in FIG. 6, peeling F occurs below the joint J of the bridge pier P due to the vibration, and the peeling F proceeds by repeating the vibration a plurality of times. It has been found that the decrease in the area at the joint J due to the progress of the peeling F is the cause of the large displacement. For this reason, in bridge pier P, the effect of joint movement restriction device 1 can be heightened by performing peeling prevention work below joint J.

(Second Embodiment)
A pier according to a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 7, the bridge pier Pa of this embodiment has the same configuration as that of the first embodiment, and further, a peeling prevention work 7 for preventing the peeling of concrete is applied below the joint J. Has been. The same code | symbol is attached | subjected to the location equivalent to 1st Embodiment. In the following description, descriptions of parts equivalent to those in the first embodiment are omitted.

  As shown in FIGS. 7 and 8, in the second embodiment, the peeling prevention work 7 is an anchor bolt 7 a driven inward from the surface of the pier Pa toward the inside. Non-shrink mortar is filled between the fixing plate 71 of the anchor bolt 7a and the surface of the pier Pa.

(Third embodiment)
A pier according to a third embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 9, the pier Pb of the present embodiment has the same configuration as that of the second embodiment, and further includes a strip-shaped steel plate 7 b attached to the surface of the pier Pb as the peeling prevention work 7. The steel plate 7b is fixed to the pier Pb by anchor bolts 7a. The steel plate 7b functions as a fixing plate for the anchor bolt 7a. The same code | symbol is attached | subjected to the location equivalent to 2nd Embodiment. In the following description, descriptions of parts equivalent to those of the second embodiment are omitted.

  As shown in FIG. 10, the steel plate 7b is attached only to the surface visible from the bridge axis perpendicular direction Y, -Y. For this reason, the steel plate 7b does not increase the width of the pier Pb in the bridge axis direction X.

(Fourth embodiment)
An pier according to a fourth embodiment of the present invention will be described with reference to FIG. As shown in FIG. 11, the pier Pc of this embodiment has the same configuration as that of the first embodiment, and further, as a peeling prevention work 7, a resin 7 c is applied in a band shape around the lower part of the joint J. Has been. The same code | symbol is attached | subjected to the location equivalent to 1st Embodiment. In the following description, descriptions of parts equivalent to those in the first embodiment are omitted.

  The resin 7c is, for example, a polyurea resin and is applied to a thickness of 2 mm. The effect of this on the width of the pier Pc in the bridge axis direction is a slight difference that can be ignored.

  In order to confirm the effect of the joint movement restriction device 1 as an earthquake countermeasure, a specimen simulating an unreinforced concrete pier was manufactured, and a static test and a dynamic experiment were performed.

  The specimen was a 1 / 2.5 scaled specimen, simulating a railway bridge that had shifted at the joint at the past major earthquake. In order to simulate the joints, the upper part of the specimen was manufactured separately from the lower part, and the part below the joints was trowel finished, and after curing, finished horizontally and smoothly with a grinder. Then, the upper part of the specimen was placed on the lower part.

  In order to grasp the friction properties of the joints, a static shear test was performed using the above specimen. The lower part of the specimen was fixed, and when the steel weight was installed on the specimen and when it was not installed, the upper part was pushed horizontally with a jack, and the load and horizontal displacement were measured. Based on the measured values, a formula representing the frictional force was created. Assuming that the frictional force at the joint is F (kN) and the vertical load is W (kN), the static frictional force is F = 0.66W, and the dynamic frictional force is F = 0.64W.

  Next, a dynamic test was performed using a large-scale vibration testing device owned by the Railway Technical Research Institute, and the behavior during an earthquake was measured. The input seismic ground motion is based on the ground surface design ground motion (L2 SpII G3 ground) wave of “Design Standards for Railroad Structures, etc., Seismic Design” (Railway Technical Research Institute, September 2012). Accordingly, the time axis is a waveform compressed to 1 / 2.5 square root≈0.632.

(Comparative example)
In the test sample of the comparative example, no joint was taken. When an acceleration of 1194 gal was applied, the horizontal displacement of the upper part with respect to the lower part from the joint during vibration was 35.93 mm, and the residual displacement after vibration was 35.98 mm. The reason why the residual displacement is slightly larger than the horizontal displacement is that the displacement due to the rotation of the rocking is added.

  The specimen of the example simulates the first embodiment and is provided with a seam movement restriction device. When an acceleration of 1248 gal was applied, the horizontal displacement during vibration was 16.95 mm, and the residual displacement after vibration was 13.90 mm.

  As a result of the dynamic test, it was confirmed that the movement at the joint is restricted by providing the joint movement restriction device on the pier.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the joint movement restriction device 1 is configured upside down from the above-described embodiment, that is, the base end side of the rod-like member 3 is fixed in the recess 2 above the joint J, and the tip side is below the joint J. It may be in the recess 2 on the side.

DESCRIPTION OF SYMBOLS 1 Joint connection restriction | limiting apparatus 2 Recessed part 21 Inner wall surface 22 Filler 3 Bar-shaped member 4 U-shaped member 5 Cushioning material 6 Space | interval material 7 Peeling prevention work 7a Anchor bolt 7b Steel plate 7c Resin J Joint P, Pa, Pb, Pc

Claims (10)

A joint movement restriction device provided on a concrete pier having a joint,
A recess formed on the side of the pier over the top and bottom of the joint,
A rod-like member housed in the recess over the top and bottom of the joint,
The base end side of the rod-shaped member is fixed in one of the recesses on the lower side and the upper side of the joint,
The joint movement restricting device according to claim 1, wherein a distal end side of the rod-shaped member is in the other concave portion on the lower side and the upper side of the joint portion, and is separated from the inner wall surface of the concave portion. In the recess, a U-shaped member is embedded in the pier so as to partially surround the periphery of the base end side of the rod-shaped member,
2. The joint movement restriction device according to claim 1, wherein a base end side of the rod-shaped member is fixed in the concave portion by filling the concave portion with a filler.   The joint movement restricting device according to claim 2, wherein a distal end side of the rod-shaped member has a shock absorbing material that absorbs an impact around the rod-shaped member.   The distal end side of the rod-shaped member has a spacing material softer than the cushioning material around the cushioning material, and the concave material around the spacing material is filled with the filler. The joint movement restricting device according to claim 1.   The said joint material is filled in a recessed part so that the surface of a bridge pier may become the same shape as before forming the said recessed part, The joint movement restriction | limiting apparatus of Claim 4 characterized by the above-mentioned. A concrete pier with joints,
A bridge pier comprising the seam movement restricting device according to any one of claims 1 to 5.   The pier according to claim 6, wherein a peeling prevention work for preventing the peeling of the concrete is provided below the joint.   The pier according to claim 7, wherein the peeling prevention work is an anchor bolt driven inward from the surface of the pier. As the peeling prevention work, further having a strip-shaped steel plate attached to the surface of the pier,
The pier according to claim 8, wherein the steel plate is attached only to a surface visible from a direction perpendicular to the bridge axis. The bridge pier according to claim 7, wherein the peeling prevention work is a resin applied in a band shape around the lower part of the joint.

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