JP4395090B2 - Replacement method for multi-function bearings on existing bridges - Google Patents

Description

  The present invention relates to a method for exchanging an existing bridge with a multi-functional bearing, and relates to a construction for replacing an existing bearing with a concrete bearing.

  Conventionally, when installing bridge supports, mortar is placed on the upper surface of the pier and the lower surface of the bridge girder, and steel support plate supports that are divided into upper and lower parts by anchor bolts are mounted on the mortar. is there.

  Since these steel support plate bearings are always exposed to wind and rain, erosion due to rust and the like is severe, so it is necessary to replace them from those that have reached the end of their service life.

  Here, when replacing the steel support plate support, the bridge girder is jacked up, concrete is removed to remove the anchor bolts and equipment embedded in the upper surface of the pier and the lower surface of the bridge girder, and then a new anchor bolt is installed. In order to install the mortar, it is necessary to place a mortar, and it is a very troublesome work to transport a new steel support plate support to a fixed position by a crane or the like.

  Therefore, there is an invention as shown in FIG. 17 for exchanging this type of support. In the present invention, the existing support is removed by jacking up the girder 101 with a jack, the new support 102 is placed on the abutment 104 via the spring 103 on the lower surface thereof, and the new support 102 is biased upward by the spring 103. The girders 101 are jacked down to a predetermined height while a non-shrink mortar is placed in the scorpion mold 105 assembled on the abutment 104, and the jack is removed after the mortar is hardened (see Patent Document 1). .)

JP 2002-242127 A (Abstract, Fig. 1)

  However, in the above invention, a spring is arranged on the lower surface of the new bearing so as to reduce the clearance between the existing girder and the upper surface of the abutment. However, the mortar is driven while maintaining the biasing force of the spring. As a result, the spring is buried in the mortar, the urging force to the existing girders disappears, and the urging force acts on the mortar, so there is a possibility that the spring collapses due to a crack caused by an impact on the mortar.

  In addition, the spring is necessary only to reduce the clearance between the existing girder and the top surface of the abutment. After the new bearing is installed, it does not perform new functions and effects, and the number of parts increases. There is a problem that becomes uneconomical.

  The present invention was devised in view of the above points, and is provided in an existing bridge that facilitates work by forming a new support by placing high-strength concrete after removing a steel support plate. The purpose is to provide an exchange method for multi-function bearings in bridges.

  In order to achieve the above object, the method of replacing the existing bridge according to the present invention to the multi-function bearing includes the steps of removing the existing lower support while supporting the existing girder in a fixed position, and removing the lower support. A step of assembling the mold on the upper surface of the pier, and a step of placing high-strength concrete in the mold and removing the mold after curing to form a new support.

  Here, by supporting the existing girder in place and removing the steel support plate support, freely assembling the formwork and placing high-strength concrete to form a new multi-function support Therefore, there is no need to assemble a new reinforcing bar in the formwork, and it is possible to replace it with a new bearing within a short period of time.

  Further, in order to achieve the above object, the method of replacing the existing bridge according to the present invention to the multi-function support removes the existing lower support and upper support that are paired up and down with the existing girder supported at a fixed position. A step of assembling a mold on the upper surface of the bridge pier and the lower surface of the girder after removing the lower support and the upper support, and placing high-strength concrete in each of the molds, removing the mold after curing, A process for forming an upper new bearing is provided.

  Here, by supporting the existing girders in place and removing the upper and lower supports made of steel, freely assembling the formwork and placing high-strength concrete to form new upper and lower supports It will be possible to switch to a new bearing in a short period of time.

  Further, in order to achieve the above object, the method of replacing the existing bridge according to the present invention with the multi-function support is to assemble the formwork between the upper surface of the pier and the lower surface of the floor slab while supporting the existing girder in a fixed position. And a step of placing high-strength concrete in the mold and removing the mold after curing to form a new support.

  Here, the existing girders were supported in place, the formwork was assembled between the pier upper surface and the floor slab lower surface, and high strength concrete was cast to form a new bearing, leaving the existing bearing plate. It can be exchanged for a new bearing as it is.

  In addition, the new bearing has a displacement limiting structure that limits the displacement of the existing girder in the direction of the bridge axis and the direction perpendicular to the bridge axis. Therefore, the displacement in the perpendicular direction can be limited by the displacement limiting structure, and the displacement in the bridge axis direction can be limited by the bridge axis direction bridge prevention structure.

  Furthermore, by forming a step-preventing structure lower than the new bearing on the front surface in the bridge axis direction of the new bearing, the bridge girder (main girder) 3 is supported by the step-preventing structure even if the new bearing is crushed by an earthquake or the like. Road steps can be prevented.

The high-strength concrete is concrete capable of obtaining a strength of 600 kg / cm ² or more, for example, high-strength fiber concrete in which steel fibers or glass fibers are mixed in mortar. By using these high-strength concretes, a reinforcing bar is not necessary, and the strength equivalent to that of a steel bearing can be maintained.

  In the present invention configured as described above, in the case of replacement work for an existing bearing, the work is very efficient by forming a new bearing with a formwork at the site, and is removed by using high-strength fiber concrete. It is possible to obtain the same strength as the bearing.

  In addition, by freely assembling the formwork and placing high-strength concrete, it is possible to replace it with a new bearing that matches the situation of the viaduct, and the construction period is shortened and it is less expensive than conventional bearings. In addition, it is possible to exchange a low-cost bearing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings to provide an understanding of the present invention.
FIG. 1 is a front view showing an initial stage in a steel bearing replacement method to which the present invention is applied, and FIG. 2 is a side view of FIG.

  In the viaduct 1 shown here, a bridge girder 3 is provided on bridge piers 2 erected on the ground A at regular intervals, and a road 4 that is an upper structure is provided on the bridge girder 3.

  Therefore, a steel support 5 is provided between the bridge pier 2 and the bridge girder 3. The steel support 5 is provided with a concrete pedestal 7 in which anchor bolts 6 are embedded on the upper surface of the pier 2, and a support plate lower part 8 of the steel support 5 is mounted on the concrete pedestal 7.

  On the other hand, a support plate upper part 9 of a steel support 5 is installed on the lower surface of the bridge girder 3 by anchor bolts 6 embedded in the lower surface of the bridge girder 3, and the support plate upper part is placed on a support plate lower part 8 of the steel support 5. Bridge girder 3 is supported with 9 placed.

  When the steel support 5 installed in this way is removed, the bridge girder 3 is supported at a fixed position by the hydraulic jack 10. As a result, a working space is secured, and the load of the support is replaced with a jack, thereby making it easy to remove the existing support.

  Next, the concrete base 7 is suspended by a core excavator or the like. In this suspending operation, when the core excavator is used for excavation from the side of the concrete pedestal 7, the concrete pedestal 7 can be easily pulled down.

  Here, as shown in FIG. 3, the support plate lower part 8 of the steel support 5 is removed, and the upper surface of the bridge pier 2 is digged down, and the exposed anchor bolt 6 is cut by a gas burner. Moreover, the steel support plate upper part 9 attached to the lower surface of the bridge girder 3 is also removed.

  Then, the steel support 5 removed by a crane or the like is removed. After the removal, the recessed portion 12 of the removed portion on the upper surface of the pier 2 and the lower surface of the pier 2 are refined.

Next, as shown in FIGS. 4 and 5, a mold 13 is provided so as to surround the periphery of the recessed portion 12. Then, high strength fiber concrete 14 is placed in the mold 13. The high-strength fiber concrete 14 is a mixture of steel fibers and glass fibers and fibrous mortar, strength of 600kg ^/ cm ² ~2000kg ^/ cm 2 by adjusting the mixing ratio of steel fibers and glass fibers It is possible to obtain the same strength as a steel support plate support.

Further, the new bearing 15 formed by the mold 13 is formed with a concave bearing receiving portion 16 on the upper surface thereof, and the lower surface of the bridge girder 3 is fitted into the bearing receiving portion 16 in a loose fit.
Therefore, after the high-strength fiber concrete 14 is cured and reaches a predetermined design strength, the mold 13 is removed, and the hydraulic jack 10 is jacked down and removed.

  Next, FIG. 6 is a front view showing another example of the steel bearing replacement method in the existing bridge of the present invention, FIG. 7 is a plan view of FIG. 6, FIG. 8 is a side view of FIG. FIG. 9 is a perspective view showing an installation state of the new bearing.

  The new concrete support 15 formed by the formwork on the upper surface of the pier 2 is provided with a drop prevention groove portion 18 as a displacement limiting structure in which the lower surface of the bridge girder (main girder) 3 is fitted on the upper surface of the bridge girder (main girder) 3. Are formed along the longitudinal direction of the bridge, and on both sides of the new bearing 15, a bridge axial displacement restriction structure moored to a bridge girder (horizontal girder) 3A and a bridge axis direction drop prevention protrusion as a bridge axis direction fall prevention structure The part 19 is formed. As a result, the bridge girder 3 can limit displacement in the direction perpendicular to the bridge axis by the drop-out preventing groove portion 18 and can limit displacement in the bridge axis direction by the bridge-axis direction drop-preventing protrusion 19. Become.

  Further, as a step-preventing structure slightly lower than the new support 15 on the front surface in the bridge axis direction of the new support 15, a quadrilateral mold is assembled on the upper surface of the pier 2, and the high-strength fiber concrete 14 is poured into the step-preventing portion 24. Is provided. Thereby, even if the new support 15 is crushed by an earthquake or the like, the step prevention unit 24 can support the bridge girder (main girder) 3 to prevent a road step.

  10 is a front view showing another example of the case where the upper new support 15A is formed on the lower surface of the bridge girder 3, FIG. 11 is an explanatory plan view in FIG. 10, FIG. 12 is a side view in FIG. 13 is a perspective view showing a state in which the upper new bearing 15A is formed on the lower surface of the bridge girder 3. FIG.

  Here, the new concrete support 15 formed by the formwork on the upper surface of the bridge pier 2 prevents displacement in the bridge axis direction in which the lower surface of the bridge girder (main girder) 3 fits on the upper surface and prevents the bridge from dropping in the bridge axis direction. A drop-preventing groove 18 as a displacement limiting structure is formed along the longitudinal direction of the bridge girder (main girder) 3, and the bridge-axis-direction bridge preventing structure in which the upper new bearing 15 A is moored in the drop-preventing groove 18. The bridge-axis direction falling bridge prevention stepped portion 20 is formed. Thereby, the bridge girder 3 can restrict the displacement in the direction perpendicular to the bridge axis by the drop-preventing groove 18 and can restrict the displacement in the bridge axis direction by the bridge axis drop-preventing step 20. .

  Further, a step prevention portion 24 as a step prevention structure that is slightly lower than the above-described new bearing 15 is provided on the front surface of the new bearing 15 in the bridge axis direction.

14 (a), (b), (c), and (d) are explanatory views showing examples in which the new bearing is provided with a rotation function. In FIG. 14 (a), the upper surface of the new bearing 15 is formed in an arc shape. By doing so, the contact area with the lower surface of the bridge girder 3 is reduced, and the swing of the upper structure can be minimized as much as possible by giving the new bearing a rotation function.
In the drawings, (B), (C), and (D) are respectively provided with rubber 17 between the upper surface of the new bearing 15 and the lower surface of the bridge girder 3, between the lower surface of the new bearing 15 and the upper surface of the pier 2 or between the new bearings 15. In this way, the new bearing has a rotating function and absorbs the moment during an earthquake.

FIGS. 15 (a), 15 (b), and 15 (c) are explanatory views showing examples in which the new bearing is provided with a horizontal movement function. FIG. 15 (a) is a diagram between the lower new bearing 15 and the upper new bearing 15A. A steel plate 21 is mounted, and the surface of these steel plates 21 is made PTFE 22 so as to have a function of moving in the horizontal direction.
In the figure, (B) and (C) are provided with a horizontal moving function by making the lower surface of the bridge girder 3 or the upper surface of the new bearing 15 into PTFE processing 22, respectively.

Next, FIG. 16 is explanatory drawing which shows the other example of the exchanging method of the steel bearing in the existing bridge of this invention.
Here, the formwork 13 is assembled between the upper surface of the pier 2 and the lower surface of the floor slab 23 of the road 4 with the bridge girder 3 supported at a fixed position, and high strength fiber concrete 14 is injected into the formwork 13, After curing, the mold 13 is removed to form a new concrete support 15, and in this case, it is possible to replace the new support 15 with the existing support plate remaining.

  Thus, in the present invention, after removing the steel support plate support, a new support can be created by placing the formwork and placing the ultra high strength fiber concrete, and the steel support plate The construction can be done in a short period of time compared to replacing the support.

Moreover, since a magnitude | size and a shape can be changed arbitrarily according to the condition of replacement | exchange time, it becomes possible to obtain the intensity | strength equivalent to steel support plate bearings.
Furthermore, it is possible to construct a new bearing with a freely-necessary size required at the site, thereby making it possible to combine the falling-bridge prevention structure and the displacement limiting structure as a single unit for multiple functions.

It is a front view which shows the initial stage in the exchange construction method to the multifunctional support in the existing bridge to which this invention is applied. It is side surface explanatory drawing in FIG. It is front explanatory drawing which shows the state which removed the steel support plate support in the exchange construction method to the multifunctional support in the existing bridge to which this invention is applied. It is front explanatory drawing which shows the creation state of the new bearing in the exchange construction method to the multifunctional bearing in the existing bridge to which this invention is applied. It is side surface explanatory drawing in FIG. It is front explanatory drawing which shows the other example of the exchange construction method to the multifunctional support in the existing bridge of this invention. It is plane explanatory drawing in FIG. It is side surface explanatory drawing in FIG. It is a perspective view which shows the attachment state of the new bearing in FIG. It is front explanatory drawing which shows the case where a new support is provided in the bridge girder lower surface in the exchange method to the multifunctional support in the existing bridge of this invention. It is plane explanatory drawing in FIG. It is side surface explanatory drawing in FIG. It is a perspective view which shows the state which provided the new bearing in the bridge girder lower surface in the replacement | exchange method to the multifunctional bearing in the existing bridge of this invention. It is explanatory drawing which shows the example which provided the rotation function in the new support in the exchange construction method to the multi-function support in the existing bridge of this invention. It is explanatory drawing which shows the example provided with the horizontal movement function in the new support in the exchange construction method to the multi-function support in the existing bridge of this invention. It is explanatory drawing which shows the other example of the exchange construction method to the multifunctional support in the existing bridge of this invention. It is explanatory drawing which shows an example of the replacement | exchange method of the conventional bridge support.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Viaduct 2 Bridge pier 3 Bridge girder 4 Road 5 Support plate support 6 Anchor bolt 7 Concrete base 8 Support plate lower part 9 Support plate upper part 10 Hydraulic jack 12 Recessed part 13 Formwork 14 High-strength fiber concrete 15 New support 16 Supporting part 17 Rubber 18 Drop-off prevention groove part 19 Bridge-axis direction drop-off prevention protrusion part 20 Bridge-axis direction drop-off prevention step part 21 Steel plate 22 PTFE processing 23 Floor slab 24 Step prevention part

Claims (12)

Removing the existing lower support while supporting the existing girder in place;
Assembling a formwork on the upper surface of the pier after removing the lower support;
A method for replacing a multi-function bearing in an existing bridge, comprising the steps of placing high-strength concrete in the mold and removing the mold after curing to form a new bearing. The displacement construction structure for restricting the displacement of the existing girder in the axial direction of the bridge is formed in the new bearing. The replacement method for the multifunctional bearing in the existing bridge according to claim 1. The displacement construction method for restricting displacement of the existing girder in the direction perpendicular to the bridge axis is formed on the new bearing. The method for replacing the existing bridge with a multifunctional bearing according to claim 1 or 2. The bridge construction method for preventing a falling bridge in the direction of the bridge axis is formed in the new bearing. 4. The method for exchanging the existing bridge with a multifunctional bearing according to claim 1, 2, or 3. 5. The method of replacing an existing bridge with a multifunctional bearing according to claim 1, wherein a step-preventing structure lower than that of the new bearing is formed on a front surface of the new bearing in the bridge axis direction. The upper surface of the said new bearing was formed in circular arc shape. The construction method for the multi-function bearing in the existing bridge according to claim 1, 2, 3, 4 or 5. Removing the existing lower and upper bearings, which support the existing girder in place and are paired up and down;
Assembling the formwork on the upper surface of the pier and the lower surface of the girder after removing the lower and upper bearings;
A method of replacing the existing bridge with a multifunctional bearing, comprising the steps of placing high-strength concrete in each of the molds, and removing the molds after curing to form a lower new bearing and an upper new bearing. The displacement construction method for restricting the displacement of the existing girder in the direction of the bridge axis is formed in the lower new bearing. The replacement method for an existing bridge according to claim 7. The displacement construction method for restricting the displacement of the existing girders in the direction perpendicular to the bridge axis is formed in the lower new bearing. The method for replacing the existing bridge with a multifunctional bearing according to claim 7 or 8. The bridge construction method for preventing a fall in the bridge axis direction for preventing a fall bridge in the bridge axis direction is formed in the lower new bearing. The method for replacing a multi-function bearing in an existing bridge according to claim 7, 8 or 9. The method for exchanging with a multi-function bearing in an existing bridge according to claim 7, 8, 9, or 10, wherein a step prevention structure lower than the lower new bearing is formed on the front surface of the lower new bearing in the bridge axis direction. . The upper surface of the lower new bearing is formed in an arc shape. The method of replacing an existing bridge with a multifunctional bearing according to claim 7, 8, 9, 10 or 11.

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