Press fitting reinforced steel plate underwater bulge prevention structure and steel plate press fitting construction method

Abstract

To provide press fitting reinforcement steel plate underwater bulge prevention structure that has a low risk of bulging or displacing a reinforcement steel plate due to an internal pressure of a filling material even in the case where a height of a columnar structure for a reinforcing object is high and a lower part thereof is located underwater, and a steel plate press fitting construction method.SOLUTION: The present invention relates to press fitting reinforcement steel plate underwater bulge prevention structure that prevents a reinforcement steel plate press-fitted for reinforcement around an existing columnar structure with a part thereof constructed underwater from bulging in filling a filling material. When constructing the existing columnar structure, a pair of bulge prevention materials with Z-shaped cross section are mounted above a water level, and a slit is formed between these bulge prevention materials. Multiple stiffeners with T-shaped cross section are mounted at an inner surface of the reinforcement steel plate. At least a part of the multiple stiffeners is inserted to the slit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a press-fit reinforced steel plate underwater bulging prevention structure and a steel plate press-fitting construction method. [Background technology]

[0002] Conventionally, a steel plate press-in method has been known in which a columnar structure is reinforced by press-in a reinforcing steel plate while the columnar structure itself bears a reaction force. For example, Patent Document 1 discloses that a press-in device is fixed to the columnar structure, and a cylindrical steel plate is press-in with a telescopic jack to reinforce the columnar structure (see paragraphs

[0026] to

[0030] of the specification of Patent Document 1, and Figures 8 to 14 of the drawings, etc.).

[0003] However, if the height of the columnar structure from the foundation is high and the height of the part reinforced with the reinforcing steel plate is large, a problem occurs in that the internal pressure of the filler material, such as mortar, filled in the gap between the steel plate and the columnar structure can cause the reinforcing steel plate to bulge or shift.

[0004] On the other hand, Patent Document 2 discloses a steel plate press-in method in which, when biased pressure such as biased earth pressure or water pressure acts on a columnar structure, spacers and rollers are attached to the rectangular reinforcing steel plate to be pressed in (see paragraphs

[0033] to

[0057] of the specification of Patent Document 2, Figures 7 to 10 of the drawings, etc.).

[0005] However, the steel plate press-in method described in Patent Document 2 assumes that the external force is biased pressure acting from the outside as a compressive force, and therefore, although this can be countered with spacers and rollers, there is a problem in that it is not possible to prevent the pressed-in steel plate from bulging out from the inside to the outside.

[0006] Furthermore, Patent Document 3 discloses a reinforcement structure for an existing columnar structure in which a flat plate portion with a Z-shaped cross section is attached near the lower end of the inner surface of the reinforcing steel plate to be pressed in to form a slit, and a restraining steel material made of H-shaped steel is inserted to fill the gap between the existing columnar structure and the reinforcing steel plate, thereby preventing the lower end of the reinforcing steel plate from separating from the existing columnar structure and protruding (see claims 1 and 2 of Patent Document 2, paragraphs

[0032] to

[0047] of the specification, Figures 1 to 8 of the drawings, etc.).

[0007] Furthermore, contrary to the reinforcement structure for columnar structures described in Patent Document 3, it is also possible to form a slit on the existing columnar structure side and insert a buckling prevention material that stiffens the reinforcing steel plate so that it does not buckle when pressed in, thereby combining the function of a bulge prevention material with the function of a guide material that guides the reinforcing steel plate vertically when pressed in.

[0008] However, when the bulge prevention material is also used as a guide material, high precision is required for marking and installation. In particular, when the bulge prevention material is located underwater, even divers face the problem of difficulty in ensuring the accuracy of the bulge prevention material during underwater construction. Furthermore, chemical anchors (registered trademark) are generally used to fasten steel materials to existing columnar structures, but using chemical anchors underwater is difficult, which also makes it difficult to attach the bulge prevention material to existing columnar structures underwater. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-167474 [Patent Document 2] Patent No. 6855151 [Patent Document 3] Patent No. 6189597 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, the present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide a press-in reinforcing steel plate underwater bulging prevention structure and steel plate press-in construction method that reduces the risk of the reinforcing steel plate bulging out or shifting due to the internal pressure of the filler, even when the existing columnar structure to be reinforced is tall and its lower part is underwater. [Means for solving the problem]

[0011] The underwater bulging prevention structure for pressed-in reinforcing steel plates of the first invention is a press-in reinforcing steel plate underwater bulging prevention structure that prevents reinforcing steel plates that are pressed in for reinforcement around existing columnar structures, part of which have been constructed underwater, from bulging when filler is filled in, and is characterized in that a pair of Z-section-shaped bulging prevention materials are attached to the existing columnar structure above the water level during construction, a slit is formed between these bulging prevention materials, and a plurality of T-section-shaped stiffening materials are attached to the inner surface of the reinforcing steel plate, with at least a portion of the plurality of stiffening materials being inserted into the slit.

[0012] The underwater bulging prevention structure for pressed-in reinforcing steel plates according to the second invention is characterized in that, in the underwater bulging prevention structure for pressed-in reinforcing steel plates described in claim 1, one or more supports made of a combination of steel materials are installed around the underwater portion of the pressed-in reinforcing steel plate to prevent the pressed-in reinforcing steel plate from bulging when filling material is filled in.

[0013] The steel plate pressing method of the third invention is a steel plate pressing method for reinforcing an existing columnar structure constructed underwater by pressing a reinforcing steel plate around it, and includes a pressing-in material installation process for installing a pair of Z-shaped cross-section anti-swelling materials above the construction water level of the existing columnar structure and forming a slit between these anti-swelling materials, a pressing-in process for pressing a pressed-in reinforcing steel plate around the existing columnar structure, and a filler filling process for filling a filler material into the gap between the pressed-in reinforcing steel plate and the existing columnar structure, and is characterized in that in the pressing-in process, a stiffening material protruding from the inner surface of the pressed-in reinforcing steel plate is inserted into the slit between the anti-swelling materials installed in the pressing-in material installation process, and the pressing-in direction is guided by the anti-swelling materials.

[0014] The steel plate pressing method according to the fourth invention is characterized in that, in the steel plate pressing method described in claim 3, it includes a support installation process, prior to the filler filling process, in which support is installed around the underwater portion of the pressed-in reinforcing steel plate to prevent the pressed-in reinforcing steel plate from becoming swollen during the filler filling process. [Effects of the Invention]

[0015] According to the first to fourth inventions, the bulge prevention material is placed above the water level during construction of the existing columnar structure, so the bulge prevention material can be attached with precision even if the existing columnar structure to be reinforced is tall and its lower part is underwater.The bulge prevention material also functions as a guide material to guide the reinforcing steel plate vertically when it is pressed in, and can prevent the reinforcing steel plate from bulging out or shifting due to the internal pressure of the filling material.

[0016] In particular, according to the second and fourth inventions, in addition to the bulge prevention material, support is installed around the underwater portion of the pressed-in reinforcing steel plate, thereby reliably preventing the reinforcing steel plate from bulging out or shifting due to the internal pressure of the filling material. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a front view of a bridge pier to which a press-fitted reinforced steel plate underwater bulging prevention structure according to an embodiment of the present invention is applied, viewed in a direction perpendicular to the bridge axis. [Figure 2] FIG. 2(a) is a plan view showing a bridge pier to which the above-mentioned press-fit reinforced steel plate underwater bulging prevention structure is applied, and FIG. 2(b) is an enlarged view of part A in FIG. 2(a). [Figure 3] FIG. 3(a) is a partially enlarged plan view showing the bulge prevention material of the press-fitted reinforced steel plate underwater bulge prevention structure, and FIG. 3(b) is a detailed elevation view showing the bulge prevention material. [Figure 4] FIG. 4 is a flowchart showing each step of the steel plate press-fitting method according to the embodiment of the present invention. [Figure 5] FIG. 5 is a process explanatory diagram showing the advance preparation for the steel plate press-fitting method. [Figure 6] FIG. 6 is a process explanatory diagram showing the step of installing a reaction steel plate in the steel plate press-in method. [Figure 7] FIG. 7 is a process explanatory diagram showing the installation process of the press-in device in the steel plate press-in method. [Figure 8] FIG. 8 is a process explanatory diagram showing the process of attaching the bulge prevention material in the steel plate press-in method. [Figure 9] FIG. 9 is a process explanatory diagram showing the reinforcing steel plate assembling process of the steel plate press-fitting method. [Figure 10] FIG. 10 is a process explanatory diagram showing the reinforcing steel plate assembly and settling process of the above-mentioned steel plate press-in method. [Figure 11] FIG. 11 is a process explanatory diagram showing the press-in process of the steel plate press-in method. [Figure 12] FIG. 12 is a process explanatory diagram showing a state in which the press-in process of the steel plate press-in method has been completed. [Figure 13] FIG. 13 is a process explanatory diagram showing the step of removing the press-in device in the steel plate press-in method. [Figure 14] FIG. 14 is a process explanatory diagram showing the first stage support assembly process in the support installation process of the steel plate press-in method. [Figure 15] FIG. 15 is a process explanatory diagram showing the second stage support assembly process in the support installation process of the steel plate press-in method. [Figure 16] FIG. 16 is a process explanatory diagram showing the first and second stage lifting point replacement process in the support installation process of the above-mentioned steel plate press-in method. [Figure 17] FIG. 17 is a process explanatory diagram showing the third stage support assembly process in the support installation process of the steel plate press-in method. [Figure 18] FIG. 18 is a process explanatory diagram showing the second stage suspension point replacement process in the support installation process of the steel plate press-in method. [Figure 19] FIG. 19 is a process explanatory diagram showing a support lowering and installation step in the support installation step of the steel plate press-in method. [Figure 20] FIG. 20 is a process explanatory diagram showing a post-installation reinforcing steel plate installation process of the steel plate press-in method. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, one embodiment of the post-processing method for preventing slippage and growth according to the present invention will be described in detail with reference to the drawings.

[0019] <Press-fitted reinforced steel plate structure to prevent underwater bulging> First, a press-fitted reinforced steel plate underwater bulging prevention structure 1 according to an embodiment of the present invention will be described using Figures 1 to 3. An existing columnar structure to which the press-fitted reinforced steel plate underwater bulging prevention structure 1 according to this embodiment is applied will be described using a pier P1 of an existing bridge constructed in a river and having an oval horizontal cross section as an example. Figure 1 is a front view of the pier P1 to which the press-fitted reinforced steel plate underwater bulging prevention structure 1 is applied, as viewed in the bridge axis direction X, Figure 2(a) is a plan view showing the pier P1 to which the press-fitted reinforced steel plate underwater bulging prevention structure 1 is applied, and Figure 2(b) is an enlarged view of part A in Figure 2(a).

[0020] 3(a) is a partially enlarged plan view showing the bulge prevention material 6 of the press-fit reinforcing steel plate underwater bulge prevention structure, and FIG. 3(b) is a detailed elevation view of the same bulge prevention material. In the figure, the symbol X indicates the bridge axis direction X of the pier P1, the symbol Y indicates the direction perpendicular to the bridge axis Y, and the symbol Z indicates the vertical direction Z. Also, H in FIG. 1 indicates the height H of the reinforced area of the columnar structure to be reinforced, and H1 indicates the height H1 of the reinforcing steel plate, which is the height H of the reinforced area minus the clearance. Furthermore, H2 is the height H2 of the press-fit reinforcing steel plate 2, and H3 indicates the height H3 of the post-construction portion.

[0021] The press-fit reinforced steel plate underwater bulging prevention structure 1 (hereinafter simply referred to as bulging prevention structure 1) of this embodiment is a press-fit reinforced steel plate underwater bulging prevention structure that prevents a press-fit reinforced steel plate 2, which is pressed into the periphery of a bridge pier P1, an existing columnar structure partially constructed underwater (in the river), for reinforcement purposes, from becoming bulged when filling material 3 is filled.

[0022] This bulge prevention structure 1 comprises a press-fit reinforcing steel plate 2 that is press-fitted around the pier P1 to reinforce the pier P1, a filler material 3 that is filled in the gap G between the press-fit reinforcing steel plate 2 and the pier P1, and a support 5 that prevents the press-fit reinforcing steel plate 2 from bulging when the filler material 3 is filled. The pier P1 also comprises a bulge prevention material 6 that moves away from the pier P1 and prevents the press-fit reinforcing steel plate 2 from bulging when the filler material 3 is filled in the gap G between the press-fit reinforcing steel plate 2 and the pier P1.

[0023] (Press-fitted reinforcing steel plate) The press-fit reinforcing steel plate 2 is made of a steel plate of a predetermined thickness (9 mm in the illustrated embodiment) according to the structural design as a base, which is welded and assembled on-site to form a reinforcing steel plate assembly 20 with an oval horizontal cross section that corresponds to the cross-sectional shape of the pier P1, as shown in Figures 2 and 3(a). Of course, it goes without saying that the shape and thickness of the press-fit reinforcing steel plate 2 may be set appropriately according to the cross-sectional shape and structural design of the existing columnar structure to be reinforced.

[0024] Furthermore, stiffeners 21 with a T-shaped cross section are provided on the inner surface of the reinforcing steel plate assembly 20 in the axial direction to stiffen the steel plate against stresses such as buckling stresses that act on the steel plate when it is pressed in. As shown in Fig. 2(a), these stiffeners 21 are densely arranged at 400 mm intervals on the flat portion 2a of the oval reinforcing steel plate assembly 20, which is at high risk of buckling, and at 800 mm intervals on the arc portion 2b. As shown in Fig. 2(a), the gap G between the press-fit reinforcing steel plate 2 and the pier P1 is set to 150 mm in this embodiment.

[0025] The post-installed reinforcing steel plate 2' shown by the diagonal lines in FIG. 1 is a post-installed portion that is installed after the press-in device (PD) and the reaction steel plate (7) described later are removed.

[0026] (filling material) The filler 3 is a general filling concrete, and the design standard strength is determined appropriately depending on the structural design. Of course, this filler 3 may be any hardening material that has a predetermined compressive strength to hold the press-fitted reinforcing steel plate 2 after a certain period of time has elapsed, and it does not have to be concrete, such as non-shrink mortar.

[0027] (Shoring) As shown in Figure 2(a), the support structure 5 is a rectangular structure made of H-shaped steel (general structural rolled steel: SS400) earth retaining material, and has the function of preventing the press-fit reinforcing steel plate 2 from becoming entrapped when the filler material 3 is filled in. H-350 x 350 x 12 x 19 H-shaped steel is used for the long sides 5a, and H-300 x 300 x 10 x 15 H-shaped steel is used for the short sides 5b. Corner pieces 5c are attached to these corners to prevent angular deformation between the perpendicular long sides 5a and short sides 5b.

[0028] As shown in Fig. 1, in this embodiment, the shoring 5 is installed at three locations at approximately equal intervals at the difference in height between the riverbed level (ground surface) L2 and the water level during construction L1 at the height of each of the first to third shoring stages. The reinforcing steel plates 2 pressed into the ground are not at risk of bulging out due to the internal pressure of the filling material 3 when being filled, and the bulging prevention material 6 described below prevents the reinforcing steel plates 2 from bulging outward above the water level during construction L1. Of course, the installation position of the shoring 5 and the dimensions of the steel material can be determined by appropriate structural calculations depending on the distance from the ground surface level L2 to the water level during construction L1, and it is also possible to install only one shoring.

[0029] The gap between the outer peripheral surface of the press-fit reinforcing steel plate 2 and the support 5 is adjusted by inserting a Uniblock (registered trademark) or wedge made of steel or the like (not shown) as a back-filling material. Of course, it is also possible to assemble the structure so that there is no gap.

[0030] (Bulging prevention material) As shown in Figures 3(a) and 3(b), the bulge prevention material 6 consists of a pair of hanging plates 61, 62 made of steel material with a Z-shaped cross section, and has the function of hanging the aforementioned stiffener 21, which has a T-shaped horizontal cross section, on the hanging plates 61, 62, preventing the pressed-in reinforcing steel plate 2 to which the stiffener 21 is joined from moving away from the pier P1 and bulging out.

[0031] As shown in Figures 3(a) and 3(b), the hanging plates 61 and 62 are spaced apart horizontally (in the direction Y perpendicular to the bridge axis) and fixed to the pier P1 with M16 chemical anchors. A slit 63 is formed between the hanging plates 61 and 62, and as shown in Figure 3(a), the stiffener 21 is inserted into the slit 63 of the bulge prevention material 6, and the flange of the stiffener 21 is hooked onto the hanging plates 61 and 62, thereby preventing the press-fit reinforcing steel plate 2 from moving away from the pier P1 and bulging.

[0032] As shown in Figure 1, this bulge prevention material 6 is installed above the construction water level L1 in the river where the pier P1 was constructed. As mentioned in the Background Art section, if the bulge prevention material 6 is also intended to function as a guide material to accurately guide the press-in direction vertically when the press-fit reinforcing steel plate 2 is pressed in, a tilted installation would hinder the press-in process. This requires high precision in marking and installation positioning, and this is why underwater installation is avoided. Here, "above the construction water level L1" refers to a situation where the majority of the bulge prevention material 6 (at least half in height) is higher than the construction water level L1 and the installation position of the chemical anchor is higher than the construction water level L1. If the installation position of the chemical anchor is higher than the construction water level L1, the bulge prevention material 6 can be easily installed on land from a float or scaffolding, as described below.

[0033] However, in the installation area (post-installed area) of the post-installed reinforcing steel plate 2' shown by diagonal lines in Figure 1, the installation of the steel plate and the filling of the filler material are carried out separately after the pressing device and the reaction steel plate are removed, so there is no need for the function as a guide material or the function of preventing bulging, and therefore no bulging prevention material 6 is installed.

[0034] 2, the illustrated embodiment shows a case where all stiffeners 21 are fastened by the bulge prevention material 6, but it is also possible to fasten only some of the stiffeners 21 by the bulge prevention material 6. This is because when the pressure when filling the filler 3 is small, it is not necessary to provide all of the stiffeners 21 as guide materials.

[0035] <Steel plate press-in method> Next, a steel plate press-in construction method according to an embodiment of the present invention will be described with reference to Figures 1 to 20. Using as an example a pier P1 constructed in a river as the above-mentioned existing columnar structure and having an oval horizontal cross section, the above-mentioned press-in reinforcing steel plate 2 is pressed into the periphery of the oval pier P1 to reinforce it.

[0036] (Advance preparation) First, in the steel plate press-in method according to this embodiment, floats are lined up and connected together around a bridge pier P1 constructed in the river as a preliminary preparation to install an assembly float F2, and then wedge-type scaffolding, frame scaffolding, etc. are assembled on top of this to install scaffolding Sf to be used during press-in and lifting, which will be described later, as shown in Figures 4 and 5. Figure 4 is a flowchart showing each step of the steel plate press-in method according to this embodiment, and Figure 5 is a process explanatory diagram showing the preliminary preparation for the steel plate press-in method according to this embodiment.

[0037] (Reaction steel plate installation process) Next, as shown in Figures 4 and 6, in the steel plate press-in method according to this embodiment, a reaction steel plate installation step is carried out to install a reaction steel plate 7 of the press-in device (PD) and a reaction steel plate 7' of the manual lifting device (LD) such as a chain block or lever block (registered trademark) on the pier P1. Figure 6 is a process explanatory diagram showing the reaction steel plate installation step of the steel plate press-in method according to this embodiment.

[0038] Specifically, in this process, post-installed anchors are installed on the top of the pier P1, and the reaction steel plates 7, 7' are then fixed and installed by bolting them to the post-installed anchors. Of course, the method of fixing the reaction steel plates 7, 7' to the pier P1 is not limited to post-installed anchors and can be determined appropriately depending on the columnar structure.

[0039] (Press-fitting device installation process) 4 and 7, in the steel plate press-in method according to this embodiment, a press-in device installation step is next performed in which a press-in device PD is attached to the reaction steel plate 7 (7') installed in the previous step. Fig. 7 is a process explanatory diagram showing the press-in device installation step in the steel plate press-in method according to this embodiment.

[0040] Specifically, in this process, the press-in device PD is supported and fixed to the top of the pier P1 by bolting to the reaction steel plate 7, and the manual lifting device LD is attached to the reaction steel plate 7'. Of course, the method of supporting and fixing the press-in device PD to the pier P1 is not limited to bolting, and it goes without saying that any method of fixing may be used.

[0041] This press-fitting device PD is a hydraulically driven linear motion mechanism, and is composed of an expansion jack J that presses in the aforementioned reinforcing steel plate assembly 20, and a pressing jig D1 made of steel that transmits the pressure of the expansion jack evenly to the reinforcing steel plate assembly 20.

[0042] (Installation process of anti-burst material) 4 and 8, the steel plate press-fitting method according to this embodiment next performs a bulge prevention material installation step of installing the above-mentioned bulge prevention material 6. Fig. 8 is a process explanatory diagram showing the bulge prevention material installation step of the steel plate press-fitting method according to this embodiment.

[0043] Specifically, in this process, multiple hanging plates 61, 62 are attached horizontally (in the direction perpendicular to the bridge axis Y) at a distance from each other on the outer surface of pier P1 above the construction water level L1, and are fixed to pier P1 with M16 chemical anchors, and slits 63 are formed between the hanging plates 61 and 62 (see Figure 3). Note that this process may be carried out simultaneously with the reinforcing steel plate assembly process described below.

[0044] (Reinforcing steel plate assembly process) 4 and 9, the steel plate press-in method according to this embodiment next performs a reinforcing steel plate assembling step for assembling one stage of reinforcing steel plate assemblies 20. Fig. 9 is a process explanatory diagram showing the reinforcing steel plate assembling step of the steel plate press-in method according to this embodiment.

[0045] Specifically, in this process, the left and right end faces of the reinforcing steel plates are welded together using full penetration welding, and a single stage of the reinforcing steel plate assembly 20 is assembled into an oval shape spaced a certain distance from the outer periphery of the pier P1. In this embodiment, since the cross-sectional shape of the pier P1 is oval, the assembly is performed to form a frame that follows the oval outer periphery, which has a similar cross-sectional shape. Of course, if the cross-sectional shape of the pier P1 is circular, elliptical, or rectangular, the assembly is performed to form a cross-sectional shape similar to that of the pier P1. Furthermore, when assembling the reinforcing steel plate assembly 20, as described above, the stiffeners 21 with a T-shaped cross section protruding from the inner surface of the reinforcing steel plate assembly 20 are inserted into the slits 63 of the bulge prevention material 6 (see Figure 3(a)).

[0046] The joining of the end faces of the press-fit reinforcing steel plate 2 is not limited to welding, and other joining methods such as mechanical joining such as rivet joining or bolt joining, or FSW (FSW Friction Stir Welding) may also be used.

[0047] (Reinforcing steel plate assembly and settling process) 4 and 10, the steel plate press-in method according to this embodiment next involves a reinforcing steel plate assembling and settling process in which the upper and lower reinforcing steel plate assemblies 20 are joined by welding or the like and then settling, and the assembling and settling are repeated until the upper and lower connected reinforcing steel plate assemblies 20 reach the riverbed surface L2, which is the ground surface. Fig. 10 is a process explanatory diagram showing the reinforcing steel plate assembling and settling process of the steel plate press-in method according to this embodiment.

[0048] Specifically, in this process, a manual lifting device LD or the like is used to join the upper and lower parts of the reinforcing steel plate assembly 20 assembled in the previous reinforcing steel plate assembly process by welding or the like and then lower them, and this assembly and lowering is repeated until the reinforcing steel plate assemblies 20 connected in order reach the riverbed surface L2, which is the ground surface.

[0049] (Press-fitting process) As shown in Figures 4 and 11, in the steel plate press-in method according to this embodiment, a press-in process is next carried out, in which the press-in device PD attached to the top of the pier P1 in the pre-press-in device installation process is used to press the reinforcing steel plate assembly 20, which reaches the riverbed surface L2 and was assembled in the reinforcing steel plate assembling and settling process, into the ground around the pier P1. At this time, soil and sand that has infiltrated into the gap G (see Figure 2(a)) between the reinforcing steel plate assembly 20 and the pier P1 is removed by spraying high-pressure water using a water jet or the like. Figure 11 is a process explanatory diagram showing the press-in process of the steel plate press-in method according to this embodiment.

[0050] As described above, the bulge prevention material 6 is attached to the outer peripheral surface of the pier P1 in the bulge prevention material attachment process, and the stiffener 21 is inserted into the slit 63 of the bulge prevention material 6 in the reinforcing steel plate assembly process, so in this process the reinforcing steel plate assembly 20 is pressed in using the bulge prevention material 6 as a guide material that guides it in the vertical direction. This allows the reinforcing steel plate assembly 20 (press-fit reinforcing steel plate 2) to be pressed in vertically with high precision.

[0051] (Repeated assembly of reinforcing steel plates and press-fitting) 4 and 12, in the steel plate press-in method according to this embodiment, the reinforcing steel plate assembling process and the press-in process are then repeated multiple times until the lower end of the reinforcing steel plate assembly 20 reaches a predetermined depth according to the structural design. Fig. 12 is a process explanatory diagram showing the state after the press-in process of the steel plate press-in method according to this embodiment is completed.

[0052] (Press-fitting device removal process) 4 and 13, in the steel plate press-in method according to this embodiment, a press-in device removal step is next performed to remove the press-in device PD installed in the press-in device installation step. Fig. 13 is a process explanatory diagram showing the press-in device removal step in the steel plate press-in method according to this embodiment.

[0053] (Shoring installation process) As shown in Figures 4 and 14 to 20, in the steel plate press-in method according to this embodiment, a support installation process is then carried out in which supports 5 are installed around the reinforcing steel plate assembly 20 (press-in reinforcing steel plate 2) to prevent the reinforcing steel plate assembly 20 (press-in reinforcing steel plate 2) from collapsing during the filler filling process described below.

[0054] Specifically, in this process, as shown in Figure 1, three sets of supports 5 are installed at approximately equal intervals around the underwater portion of the press-fit reinforcing steel plate 2 between the water level L1 during construction and the riverbed surface L2, in rows 1 to 3 from the bottom.

[0055] First, in this process, as shown in Fig. 14, a first-stage shoring assembly process is carried out in which a manual lifting device LD such as a chain block is used to lift and support the first stage of shoring 5 from the bottom on the float F2, assembling the long side portions 5a, short side portions 5b, corner pieces 5c, etc. (see also Fig. 2(a)). Fig. 14 is a process explanatory diagram showing the first stage shoring assembly process in the shoring installation process of the steel plate press-in method according to this embodiment.

[0056] Next, in this process, as shown in Fig. 15, the lifting support of the first stage shoring 5 is transferred from the manual lifting device LD to the reaction steel plate 7 using a wire or the like, and then the freed manual lifting device LD is used to lift and support the H-shaped steel, which is an earth retaining material, and a second stage shoring assembly process is carried out in which the second stage shoring 5 from the bottom is assembled on the float F2. Fig. 15 is a process explanatory diagram showing the second stage shoring assembly process in the shoring installation process of the steel plate press-in method according to this embodiment.

[0057] Furthermore, in this process, as shown in Fig. 16, after assembling the second-stage shoring 5, a first-stage / second-stage hanging point changing process is carried out in which the hanging point for the lifting support of the second-stage shoring 5 is changed from the manual lifting device LD to the reaction steel plate 7, and the hanging point of the first-stage shoring 5 is changed from the reaction steel plate 7 to the assembled second-stage shoring 5 by tying the wire with a wire or the like. Fig. 16 is a process explanatory diagram showing the first-stage / second-stage hanging point changing process in the shoring installation process of the steel plate press-in method according to this embodiment.

[0058] Next, in this process, as shown in Fig. 17, a third-stage shoring assembly process is carried out in which the H-shaped steel is lifted and supported using the free manual lifting device LD, and the third stage of shoring 5 from the bottom is assembled on the float F2 (see also Fig. 2(a)). Fig. 17 is a process explanatory diagram showing the third-stage shoring assembly process in the shoring installation process of the steel plate press-in method according to this embodiment.

[0059] Next, in this process, as shown in Fig. 18, after assembling the third stage shoring 5, a second stage hanging point replacement process is carried out in which the hanging point of the second stage shoring 5 is replaced with the third stage shoring 5 assembled from the reaction steel plate 7. Fig. 18 is a process explanatory diagram showing the second stage hanging point replacement process in the shoring installation process of the steel plate press-in method according to this embodiment.

[0060] Finally, in this process, as shown in Fig. 19, a support lowering and installation process is performed in which the first to third stages of shoring 5 are lowered all together to a predetermined position using a manual lifting device LD, and Uniblock (registered trademark) made of steel or the like is inserted as a back-filling material into the gap G between the outer circumferential surface of the reinforcing steel plate assembly 20 (press-fit reinforcing steel plate 2) and the shoring 5 to secure it in place. Fig. 19 is a process explanatory diagram showing the support lowering and installation process in the shoring installation process of the steel plate press-fitting method according to this embodiment.

[0061] (Cleaning process) As shown in FIG. 4, in the steel plate press-fitting method according to this embodiment, a cleaning step is then carried out to clean the gap G, which is the clearance at the time of press-fitting.

[0062] Specifically, in this process, soil and floating matter adhering to the inner surface of the reinforcing steel plate assembly 20, the surface of the pier P1, and the gap G are washed away and cleaned by spraying high-pressure water using a water jet or the like.

[0063] (Filling material filling process) As shown in Figure 4, in the steel plate press-in method according to this embodiment, a filler filling process is then carried out in which the filler 3 is filled into the gap G between the reinforcing steel plate assembly 20 and the pier P1 (see Figures 2(a) and 2(b)).

[0064] In this process, the gap G that has been cleaned in the pre-cleaning process is filled with a filler 3 made of a cement-based time-hardening material such as mortar or concrete. Note that the filler 3 to be filled is not limited to a cement-based time-hardening material, and it may also be a filler made by mixing a resin-based adhesive such as an epoxy resin into a filler.

[0065] (Shoring dismantling and removal process) As shown in Fig. 4, in the steel plate press-in method according to this embodiment, a shoring dismantling and removal process is next carried out in which the first to third tiers of shoring installed in the shoring installation process are dismantled and removed. In this process, which is the reverse of the shoring lowering and installation process described above and shown in Fig. 19, the first to third tiers of shoring 5 are lifted together above the float F2 using a manual lifting device LD, and while rearranging the suspension points, they are dismantled and removed in order, starting with the lowest tier of shoring 5.

[0066] After all of the support structures 5 have been dismantled and removed, the reaction steel plates 7 that are no longer needed are also removed.

[0067] (Post-installation reinforcing steel plate installation process) As shown in Figures 4 and 20, the steel plate press-in method according to this embodiment next involves a post-installed reinforcing steel plate assembly and installation process in which a reinforcing steel plate assembly 20' of the post-installed reinforcing steel plate 2', which is the aforementioned post-installed portion indicated by the diagonal lines, is assembled and installed on scaffolding. This process is carried out in the same way as in the conventional steel plate winding method. Figure 20 is a process explanatory diagram showing the post-installed reinforcing steel plate installation process of the steel plate press-in method according to this embodiment.

[0068] (Post-construction filler filling process) Thereafter, as shown in Figure 4, in the steel plate pressing method according to this embodiment, a post-installation filler filling process is carried out in which the aforementioned filler 3 is filled into the gap G (see Figure 2(a)) between the reinforcing steel plate assembly 20' of the post-installation reinforcing steel plate 2' installed in the pre- and post-installation reinforcing steel plate installation process and the pier P1.

[0069] After this post-installation filler filling process is completed, the filler 3 hardens and the reinforcing steel plate assemblies 20', 20 and the pier P1 are integrated, thereby completing the steel plate press-in method according to this embodiment. Of course, if necessary, anti-corrosion coating may be applied to the press-in reinforcing steel plates 2 and the post-installation reinforcing steel plates 2'.

[0070] According to the bulge prevention structure 1 and steel plate press-in method of this embodiment described above, the bulge prevention material 6 is provided above the water level during construction, so the bulge prevention material 6 can be attached with precision even if the height of the existing columnar structure (pier P1) to be reinforced is high and its lower part is underwater. Therefore, according to the bulge prevention structure 1 and steel plate press-in method, the bulge prevention material 6 also functions as a guide material that guides the press-in reinforcing steel plate 2 in the vertical direction when it is pressed in, allowing it to be pressed in accurately, and preventing the press-in reinforcing steel plate 2 from bulging out or shifting due to the internal pressure of the filler material 3.

[0071] Furthermore, according to the bulge prevention structure 1 and the steel plate press-in method, in addition to the bulge prevention material 6, support structures 5 are installed around the underwater portion of the pressed-in reinforcing steel plate 2, so that the internal pressure of the filling material 3 can reliably prevent the pressed-in reinforcing steel plate 2 from bulging out or shifting.

[0072] The above has described in detail the underwater bulging prevention structure 1 for press-fitted reinforced steel plates according to an embodiment of the present invention and the steel plate press-fitting method using the same. However, the above-described and illustrated embodiments are merely specific embodiments for carrying out the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments. [Explanation of symbols]

[0073] 1: Press-fit reinforced steel plate structure to prevent underwater bulging 2: Press-fit reinforced steel plate 2': Post-installed reinforced steel plate 2a: Flat part 2b: Arc section 20,20': Reinforced steel plate assembly 21: Stiffener 3: Filling material 5: Shoring 5a: Long side 5b: Short side 5c: Corner piece 6: Anti-burst material 61, 62: Hook plate 63: Slit D1: Pressing jig F2: Float G: Gap J: Telescopic jack L1: Water level during construction L2: River bed surface LD: Manual lifting device P1: Pier PD: Press-fit device Sf: Scaffolding

Claims

1. A press-fit reinforcing steel plate underwater bulging prevention structure that prevents a reinforcing steel plate pressed into the periphery of an existing columnar structure partially constructed underwater from bulging when a filler material is filled in, A pair of Z-shaped cross-section bulge prevention materials are attached to the existing columnar structure above the construction water level, and a slit is formed between these bulge prevention materials. A plurality of stiffeners with a T-shaped cross section are attached to the inner surface of the reinforcing steel plate. At least a part of the plurality of stiffeners is inserted into the slits. A press-fit reinforced steel plate structure that prevents underwater bulging.

2. A single or multiple supports made of steel materials are installed around the underwater portion of the press-fit reinforcing steel plate to prevent the press-fit reinforcing steel plate from being engulfed when filling the filler.

2. The underwater bulging prevention structure of claim 1, wherein:

3. A steel plate press-in method for reinforcing an existing columnar structure constructed underwater by pressing in a reinforcing steel plate around the columnar structure, a step of attaching a pair of Z-shaped bulge prevention materials to the existing columnar structure above the construction water level and forming a slit between the bulge prevention materials; a press-in process of press-in reinforcing steel plates around the existing columnar structure; a filler filling step of filling a filler material into a gap between the press-fitted reinforcing steel plate and the existing columnar structure, In the press-fitting step, stiffeners protruding from the inner surface of the press-fit reinforcing steel plate are inserted into the slits between the bulge prevention materials attached in the bulge prevention material attachment step, and the press-fitting is performed while the bulge prevention materials guide the press-fitting direction. This is a steel plate press-in method characterized by the following.

4. A support installation process is provided in which, before the filler filling process, a support is installed around the underwater portion of the press-fit reinforcing steel plate to prevent the press-fit reinforcing steel plate from sagging during the filler filling process. The steel plate press-fitting method according to claim 3,

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