JP2013159970A - Unequal thickness steel pipe and structure employing unequal thickness steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationally design a steel pipe to be used as a skeleton of a specific structure in which a direction where a bending moment acts greatly is determined or a portion to promote corrosion is determined, and to reduce costs as a result.SOLUTION: An unequal thickness steel pipe 1 is used which comprises a thin cross section 11 which is provided in a part of a pipe circumferential direction, and a thick cross section 13 which is provided in a portion different from the thin cross section 11 in the pipe circumferential direction and is formed thicker than the thin cross section 11. When installing the unequal thickness steel pipe 1 is in a structure 3 as a skeleton 31, it is installed in such a manner that the thick cross section 13 is located in a predetermined portion in accordance with an install position.

Description

  The present invention relates to an unequal thickness steel pipe used as a structural body of a civil engineering structure or a building structure, and a structure using the unequal thickness steel pipe.

  Conventionally, steel pipes such as steel pipe columns, steel pipe piles, steel pipe sheet piles, and steel pipe main girders have been frequently used as the structures of civil engineering structures and building structures. As this steel pipe, those having the same outer diameter, inner diameter, and wall thickness are generally used in the pipe axis direction and the pipe circumferential direction.

  As other steel pipes, a tapered steel pipe formed so that the outer diameter continuously decreases from one to the other in the pipe axis direction is known (for example, see Patent Document 1). This tapered steel pipe is suitably used as a flag pole, an illumination lamp support, or the like.

Japanese Unexamined Patent Publication No. 07-279483

  By the way, as mentioned above, since the general steel pipe is formed so that thickness may become equal toward the pipe circumferential direction, it can exhibit the load resistance equivalent to the bending moment from all directions. However, depending on the installation location of this steel pipe, the direction in which the bending moment acts largely is determined, and the bending stress generated by the bending moment with respect to a part of the pipe circumferential direction is greater than other parts in the pipe circumferential direction. There is a case. In this case, in the conventional steel pipe structure, the wall thickness is increased equally over the entire range in the pipe circumferential direction so that sufficient strength against bending moment can be exerted at a specific part where the bending stress degree is large. From the viewpoint of cost reduction, there was room for further study.

  Moreover, the same problem has arisen also when using the above-mentioned general steel pipe about the steel pipe main body of the steel pipe sheet pile wall used as a seawall, a breakwater, etc. That is, in this case, it is known that corrosion is particularly promoted at the portion of the steel pipe main body that protrudes most toward the water area. If such corrosion occurs, the load bearing capacity is lost, and buckling may occur. For this reason, in general, it is necessary to perform an anticorrosion treatment so that a sufficient anticorrosion performance is obtained at the most protruding portion of the steel pipe main body, which causes a cost increase.

  Therefore, the present invention has been devised in view of the above-mentioned problems, and the purpose of the present invention is to determine the direction in which the bending moment acts greatly, or to determine the site where corrosion is promoted. For steel pipes that are used as the housing of a specific structure, we provide an unequal-thickness steel pipe and a structure using an unequal-thickness steel pipe that can be rationally designed and that can reduce costs. There is to do.

  In order to solve the above-described problems, the present inventors have invented a structure using the following unequal thickness steel pipe and the unequal thickness steel pipe after intensive studies.

  The structure using the unequal thickness steel pipe according to the first invention is a structure having a steel pipe installed as a casing, wherein the steel pipe has a thin cross section provided in a part of the pipe circumferential direction, and the thin cross section. A non-uniform thickness steel pipe provided with a thick cross section formed thicker than the thin cross section, provided in different parts in the pipe circumferential direction with respect to the part, and according to the installation location of the steel pipe in advance It is installed so that the said thick cross section may be located in the defined site | part.

  A structure using an unequal thickness steel pipe according to a second aspect of the present invention is the structure according to the first aspect, wherein the steel pipe has a larger bending stress degree with respect to a part in the pipe circumferential direction than in other parts in the pipe circumferential direction. And the thick-walled cross-sectional portion is located in a portion where the degree of bending stress is greater than that of other portions.

  A structure using an unequal thickness steel pipe according to a third aspect of the present invention is the structure according to the first aspect, wherein the steel pipe is used as a steel pipe main body having a steel pipe sheet pile wall placed at a boundary between a water area and soil. It is installed so that the said thick cross section may be located in the site | part most protruded to the water area side of the main body.

  A structure using an unequal thickness steel pipe according to a fourth aspect of the present invention is the structure according to any one of the first to third aspects, wherein the steel pipe is a tapered steel sheet or a differential thickness steel sheet having the thin section and the thick section. At least one steel plate including a bend, the bent steel plate is arranged in a cylindrical shape by abutting the circumferential end portion, and the circumferential end portion of the abutted steel plate is joined and configured. It is characterized by.

  A structure using an unequal thickness steel pipe according to a fifth aspect of the present invention is the structure according to any one of the first to fourth aspects, wherein the thick-walled cross section includes a central portion for each half-circumferential portion in the pipe circumferential direction. The thin-walled cross-sectional portion is provided between the thick-walled cross-sectional portions provided for each of the half-circumferential portions.

  A structure using an unequal thickness steel pipe according to a sixth aspect of the present invention is the structure according to any one of the first aspect to the fourth aspect, wherein the thick-walled cross-section has a central portion for every ¼ circumferential portion in the pipe circumferential direction. The thin-walled cross-sectional portion is provided between the thick-walled cross-sectional portions provided for each of the ¼ circumferential portions.

  A structure using an unequal thickness steel pipe according to a seventh aspect of the present invention is the structure according to any one of the first to sixth aspects, wherein the thick section is provided only in a range including a central portion of a half-circumferential portion in the pipe circumferential direction. The thin-walled cross-sectional portion is provided in a portion in the pipe circumferential direction other than the thick-walled cross-sectional portion.

  The structure using the unequal thickness steel pipe according to the eighth invention is any one of the first invention to the seventh invention, wherein the unequal thickness steel pipe is filled with a time-hardening filler. Features.

  The structure using the unequal thickness steel pipe according to the ninth invention is the structure according to any one of the fourth to eighth inventions, wherein the unequal thickness steel pipe is joined by welding the peripheral ends of the abutted steel sheets. It is characterized by being.

  An unequal thickness steel pipe according to a tenth aspect of the present invention is a thin-walled cross-section portion provided in a part of the pipe-circumferential direction, and is provided in a portion different in the pipe-circumferential direction with respect to the thin-wall cross-section portion. And a thick cross section formed thick.

  An unequal thickness steel pipe according to an eleventh aspect of the invention is the tenth aspect of the invention, wherein at least one or more steel plates including a tapered steel plate or a differential thickness steel plate having the thin section and the thick section are bent, and the bending process is performed. The formed steel plate is arranged in a cylindrical shape by abutting the peripheral end portions, and the peripheral end portions of the abutted steel plates are joined to each other.

  The unequal thickness steel pipe according to a twelfth aspect of the invention is the tenth aspect of the invention or the eleventh aspect of the invention, wherein the thick cross section is provided in a range including a central portion for each half circumference portion in the pipe circumferential direction, Further, it is provided between the thick-walled cross-sectional portions provided for each of the half-circumferential portions.

  The unequal thickness steel pipe according to a thirteenth aspect of the invention is the tenth aspect of the invention or the eleventh aspect of the invention, wherein the thick section is provided in a range including the central portion for every ¼ circumferential portion in the pipe circumferential direction. A cross-sectional part is provided between the thick cross-sectional parts provided for every said 1/4 circumference part, It is characterized by the above-mentioned.

  The unequal thickness steel pipe according to the fourteenth aspect of the invention is the tenth aspect of the invention or the eleventh aspect of the invention, wherein the thick cross section is provided only in a range including the central part of the semicircular portion in the pipe circumferential direction, It is provided in a portion in the pipe circumferential direction other than the thick cross section.

  The unequal thickness steel pipe according to a fifteenth aspect of the present invention is characterized in that, in any of the eleventh to fourteenth aspects, the peripheral ends of the abutted steel sheets are joined by welding.

  According to the first invention to the fifteenth invention, it is possible to rationally design a steel pipe used as a casing of a specific structure, and it is possible to reduce the cost.

  In particular, according to the second invention, when the direction in which the bending moment acts greatly is determined, by increasing the thickness of the portion where the bending stress generated by the bending moment is greater than other portions, It becomes possible to effectively increase the yield strength against the bending moment while suppressing the amount of steel used.

  Further, according to the third invention, the thickness of the portion that protrudes most to the water area is thick enough that the load bearing capacity is not lost even if corrosion occurs within a predetermined period, and is thicker than other portions. By making it thick, it becomes possible to take anticorrosion measures while suppressing the amount of steel used.

  Moreover, according to the 4th invention and the 11th invention, it becomes possible to manufacture an unequal thickness steel pipe easily using a taper steel plate or a differential thickness steel plate.

  Further, according to the fifth and twelfth inventions, when an unequal thickness steel pipe is used for a casing in which a bending moment repeatedly acts on both sides in one direction, a bending moment that acts repeatedly on both sides in one direction while suppressing the amount of steel used. It is possible to effectively increase the proof stress against.

  Further, according to the sixth and thirteenth inventions, when using an unequal thickness steel pipe for a casing in which bending moments repeatedly act on both sides perpendicular to each other, both sides perpendicular to each other are suppressed while suppressing the amount of steel used. It is possible to effectively increase the proof stress against a bending moment that repeatedly acts on the substrate.

  Further, according to the eighth invention, the filler resists the compressive stress generated in the steel pipe cross section, and the steel material resists the tensile stress generated in the steel pipe cross section, thereby filling the compressive stress and tensile stress. It can be efficiently borne by the steel and steel materials, and it becomes possible to design more rationally.

An example of the unequal thickness steel pipe which concerns on this invention is shown, (a) is sectional drawing which shows the unequal thickness steel pipe comprised by the four piece taper steel plate, (b) is two double taper It is sectional drawing which shows the unequal thickness steel pipe comprised by the steel plate, (c) is sectional drawing which shows the unequal thickness steel pipe comprised by the two center taper steel plates. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an example of an unequal thickness steel pipe according to the present invention, in which (a) is a cross-sectional view showing an unequal thickness steel pipe composed of two single taper steel plates and one steel plate having an equal thickness. And (b) is a cross-sectional view showing an unequal thickness steel pipe constituted by one double-tapered steel plate and one steel plate having the same thickness. It is an example of the unequal thickness steel pipe which concerns on this invention, and is sectional drawing which shows the unequal thickness steel pipe comprised by one both taper steel plates and four steel plates with equal thickness. An example of the unequal thickness steel pipe which concerns on this invention is shown, It is sectional drawing which shows the unequal thickness steel pipe comprised by the double taper steel plate of 4 sheets. It is an example of an unequal thickness steel pipe concerning the present invention, and is a sectional view showing an unequal thickness steel pipe constituted by one double taper steel plate. It is an example of an unequal thickness steel pipe concerning the present invention, and is a sectional view showing an unequal thickness steel pipe constituted by two sheets of differential thickness steel sheets and one steel sheet having the same thickness. (A) is sectional drawing which shows an example of a single taper steel plate, (b) is sectional drawing which shows an example of both taper steel plates, (c) is sectional drawing which shows an example of a center taper steel plate. It is sectional drawing which shows an example of a difference thickness steel plate. It is a figure showing roughly an example of a bridge in which an unequal thickness steel pipe concerning the present invention is used as a steel pipe main girder. (A) is a perspective view which shows roughly an example of the bridge in which the unequal thickness steel pipe concerning this invention is used as a steel pipe pier, (b) is a plane sectional view of the unequal thickness steel pipe. (A) is a plane sectional view showing an example of a concrete structure in which an unequal thickness steel pipe concerning the present invention is used as a steel pipe pile, and (b) is the front sectional view. It is a plane sectional view showing an example of the structure by which the unequal thickness steel pipe concerning the present invention was used as a steel pipe sheet pile wall. It is sectional drawing which shows an example of what was filled with the time-hardening filler in the unequal thickness steel pipe which concerns on this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing an unequal thickness steel pipe to which the present invention is applied and a structure using the unequal thickness steel pipe will be described in detail with reference to the drawings.

  First, an unequal thickness steel pipe to which the present invention is applied will be described. 1-6 is sectional drawing which shows an example of the unequal thickness steel pipe 1 which concerns on this invention, respectively.

  As shown in FIGS. 1 to 6, the unequal-thickness steel pipe 1 according to the present invention has a thin cross-sectional portion 11 provided in a part of the pipe circumferential direction, and the pipe circumferential direction is different from the thin cross-sectional portion 11. And a thick-walled cross-sectional portion 13 provided at the site. The thick cross section 13 is formed thicker than the thin cross section 11.

  From the thin section 11 to the thick section 13, in the example shown in FIGS. 1 to 5, it is formed in a tapered shape so that the thickness continuously increases. Thus, when formed in a taper shape, the largest thickness part 13a from which the thickness becomes the maximum in a part of thick section 13 is provided. In addition to this, the thin-walled cross-sectional portion 11 to the thick-walled cross-sectional portion 13 may be formed stepwise so that the thickness gradually increases as shown in FIG. Details of the range in which the thick cross section 13 and the thin cross section 11 are provided will be described later.

  As shown in FIGS. 1 to 8, the unequal thickness steel pipe 1 having the thin cross section 11 and the thick cross section 13 as described above is a tapered steel plate having the thin cross section 11 and the thick cross section 13. 21 or at least one steel plate 20 including the differential thickness steel plate 23.

  As shown in FIG. 7, the tapered steel plate 21 refers to a steel plate whose thickness changes continuously in a direction A substantially parallel to the tapered steel plate 21. As shown in FIG. 8, the differential thickness steel plate 23 has a thin cross-section portion 11 and a thick cross-section portion 13 that are equal in thickness toward one direction A substantially parallel to the differential thickness steel plate 23, and It refers to a steel plate in which the thin cross section 11 and the thick cross section 13 are continuous at the step portion 23a. The tapered steel plate 21 and the differential thickness steel plate 23 are obtained, for example, by rolling.

  As the taper steel plate 21, for example, as shown in FIG. 7A, the plate thickness continuously increases from one end 21a to the other end 21b in one direction A substantially parallel to the taper steel plate 21 (hereinafter referred to as this). A single-taper steel plate). In addition to this, as shown in FIG. 7B, the taper steel plate 21 continuously increases in thickness from both ends 21a, 21b in one direction A substantially parallel to the taper steel plate 21 to the central portion 21c. (Hereinafter, this is referred to as a double-tapered steel plate), or as shown in FIG. 7C, the plate thickness is continuously reduced from both ends 21a, 21b in one direction A to the central portion 21c (hereinafter, This is referred to as a center tapered steel plate). In addition, the taper steel plate 21 may be provided with a portion having an equal plate thickness at an intermediate position from one end 21a to the other end 21b in one direction A substantially parallel to the taper steel plate 21.

  Moreover, as shown in FIGS. 1-6, the unequal thickness steel pipe 1 which concerns on this invention bends the at least 1 or more steel plate 20 containing such a taper steel plate 21 or the differential thickness steel plate 23, and the 1 It is preferable that two or more steel plates 20 are arranged in a cylindrical shape by abutting the peripheral end 20a, and the abutted peripheral end 20a is joined by welding or the like. This makes it possible to easily manufacture the unequal thickness steel pipe 1 using the tapered steel plate 21 and the differential thickness steel plate 23. In addition, the detail of the steel plate 20 used for this unequal thickness steel pipe 1 is mentioned later.

  Next, a structure using the unequal thickness steel pipe 1 according to the present invention will be described. 9-12 is a figure which shows an example of the structure 3 using the unequal thickness steel pipe 1 which concerns on this invention, respectively.

  The structure 3 to which the present invention is applied is used as a civil engineering structure such as a bridge, footing, revetment, breakwater, etc., and a building structure. An object in which the unequal thickness steel pipe 1 is installed at a predetermined position as the casing 31 of the structure 3 such as a sheet pile wall is a target. In addition, the structure 3 to which the present invention is applied is affected by external factors such as bending moment and corrosion on the unequal thickness steel pipe 1 installed at a predetermined position as the casing 31 of the structure 3. A specific structure 3 that is larger than other parts in a part in the tube circumferential direction is a target. And the unequal thickness steel pipe 1 which concerns on this invention is installed so that the thick section 13 of the unequal thickness steel pipe 1 may be located in the site | part previously determined according to the installation location of the unequal thickness steel pipe 1. The

  First, as the specific structure 3, the direction in which the bending moment acts largely is determined, and the bending stress generated by the bending moment with respect to a part in the pipe circumferential direction is larger than the other parts in the pipe circumferential direction. The case where the unequal thickness steel pipe 1 which concerns on this invention is used with respect to the structure 3 which has the housing 31 is demonstrated. Examples of the frame 31 of the structure 3 include a steel pipe main girder of a bridge, a steel pipe pier of the bridge, a steel pipe pile joined to a footing, and the like.

  The case where the unequal thickness steel pipe 1 which concerns on this invention is used for the steel pipe main girder 42 of the bridge 41 is demonstrated. As shown in FIG. 9, the bridge 41 is composed of a plurality of steel pipe main girders 42 arranged in parallel with each other in the bridge axis orthogonal direction Y, and an H-section steel connecting the plurality of steel pipe main girders 42. And a floor slab 44 supported by a plurality of steel pipe main girders 42. A bending moment acts on the steel pipe main girder 42 functioning as the frame 31 of the bridge 41 around the direction axis in the direction orthogonal to the bridge axis Y by a load of a vehicle or the like traveling on the floor slab 44. The degree of bending stress due to this bending moment is greater than the other part for each of the upper part 42a and the lower part 42b of the steel pipe main girder 42.

  Here, as for the structure 3 according to the present invention, as an embodiment thereof, the unequal thickness steel pipe 1 used as a casing 31 having a bending stress degree generated with respect to a part in the pipe circumferential direction larger than other parts, It is characterized in that the thick-walled cross-sectional portion 13 is located at a portion where the bending stress degree is larger than that at other portions. In the example shown in FIG. 9, the unequal thickness steel pipe is used as the steel pipe main girder 42 so that the thick section 13 of the unequal thickness steel pipe 1 is located in each of the upper part 42a and the lower part 42b of the steel pipe main girder 42. 1 is installed.

  Next, the case where the unequal thickness steel pipe 1 which concerns on this invention is used for the steel pipe pier 45 of the bridge 41 is demonstrated. As shown in FIG. 10, the bridge 41 includes a steel pipe pier 45 as a lower structure. In the illustrated example, the steel pipe pier 45 is coupled to an overhanging portion 47 provided along the bridge axis orthogonal direction Y at the upper portion 45a. Superstructure consisting of girders etc. will be installed. For such a steel pipe pier 45, when an earthquake occurs, seismic force in the bridge axis orthogonal direction Y and the bridge axis direction X acts on the upper part 45a. The bending moment acting on the steel pier 45 by this seismic force is generally greater in the component around the bridge axis direction X-axis than the component around the bridge axis orthogonal direction Y-axis. A greater degree of bending stress is generated at each of both end portions 45b of Y than at other portions. In this case, in the structure 3 according to the present invention, the unequal thickness steel pipe 1 as the steel pipe pier 45 is thicker than the unequal thickness steel pipe 1 at each end portion 45b in the bridge axis orthogonal direction Y of the steel pipe pier 45. It is installed so that the cross section 13 is located.

  Next, the case where the unequal thickness steel pipe 1 which concerns on this invention is used for the steel pipe pile 48 joined to a footing etc. is demonstrated. As shown in FIG. 11, the steel pipe pile 48 is placed on a ground (not shown), and the pile head portion 48a is joined to a concrete structure 49 such as a footing via a reinforcing bar (not shown). Has been. When such a concrete structure 3 is used as a bridge pier foundation or the like, when an earthquake occurs, the seismic force component in one direction P among the directions P and Q orthogonal to each other is the same as described above. When it becomes larger, a greater bending stress degree is generated in the pile head portion 48a of the steel pipe pile 48 than in other portions with respect to both end portions 48b in one direction P thereof. In the example shown in FIG. 11, the case where the seismic force component in the vertical direction P in FIG. In this case, in the structure 3 according to the present invention, the unequal thickness steel pipe 1 as the steel pipe pile 48 is provided with a thick cross section of the unequal thickness steel pipe 1 at each end portion 48b in one direction P of the steel pipe pile 48. 13 is located.

  In addition, as the unequal thickness steel pipe 1 that satisfies the conditions described in the examples shown in FIGS. 9 to 11, as shown in FIG. 1, the central portion 15 is provided for each half circumference portion of the unequal thickness steel pipe 1. What is provided with the thick cross section 13 in a range including

  In this way, when the direction in which a large bending moment acts is determined, the amount of steel used can be reduced by increasing the thickness of the portion where the bending stress generated by the bending moment is greater than the other portions. However, it is possible to effectively increase the yield strength against the bending moment. For this reason, it is possible to rationally design the steel pipe used as the casing 31 of the specific structural body 3 in which the direction in which the bending moment acts greatly is determined, and it is possible to reduce the cost.

  Next, the case where the unequal thickness steel pipe 1 which concerns on this invention is used for the steel pipe sheet pile wall 51 applied as a seawall, a breakwater, etc. is demonstrated. The steel pipe sheet pile wall 51 is placed at a boundary portion 54 between a water area 52 such as the sea or a river and an existing ground or soil 53 such as embankment, and a plurality of steel pipe sheet piles 55 placed on the ground. Built in combination. The steel pipe sheet pile 55 includes a steel pipe main body 56 made of the unequal thickness steel pipe 1 and a pair of joints 57 joined to the steel pipe main body 56 by welding or the like. Adjacent steel pipe sheet piles 55 are driven into the ground in a state where they are connected to each other via a joint 57, whereby the steel pipe sheet pile wall 51 is constructed.

  Here, when used for the steel pipe sheet pile wall 51 as a revetment or the like, it is known that corrosion is particularly promoted at a portion 58 that protrudes most to the water area side of the steel pipe main body 56. And the structure 3 which concerns on this invention is the unequal thickness steel pipe 1 as the steel pipe main body 56 so that the thick cross-section part 13 may be located in the site | part 58 most protruded to the water area side of the steel pipe main body 56 as one embodiment. It is characterized by being installed. Thereby, about the thickness of the unequal thickness steel pipe 1 of the portion 58 that protrudes most to the water area side, the thickness is such that the load bearing capacity is not lost even if corrosion occurs within a predetermined period. By making it thick, it becomes possible to take anti-corrosion measures while suppressing the amount of steel used. For this reason, it is possible to rationally design the steel pipe used as the casing 31 of the specific structure 3 in which the site where corrosion is promoted is determined, and it is possible to reduce the cost.

  As described above, according to the unequal thickness steel pipe 1 and the structure 3 according to the present invention, it is possible to rationally design the steel pipe used as the casing 31 of the specific structure 3 and to reduce the cost. It becomes possible.

  In addition, the number of thick cross sections 13 of the unequal thickness steel pipe 1 is determined in consideration of the bending moment and its direction due to seismic force acting on the unequal thickness steel pipe 1 and the influence of external factors such as corrosion. That number is set. When the unequal thickness steel pipe 1 is used for the casing 31 in which the bending moment due to the seismic force or the like repeatedly acts on both sides in one direction as in the examples shown in FIGS. It is preferable to use what the thick cross-sectional part 13 was provided in the range including the center part 15 for every half periphery part of the pipe circumferential direction as shown in FIG. This makes it possible to effectively increase the yield strength against bending moments that repeatedly act on both sides in one direction while suppressing the amount of steel used.

  In addition, when the unequal thickness steel pipe 1 is used for the casing 31 in which bending moments repeatedly act on both sides perpendicular to each other, the unequal thickness steel pipe 1 is ¼ of the pipe circumferential direction as shown in FIG. It is preferable to use one having a thick cross section 13 in a range including the central portion 15 for each peripheral portion. This makes it possible to effectively increase the yield strength against bending moments that repeatedly act on both sides of the two directions orthogonal to each other while suppressing the amount of steel used.

  Further, due to external factors such as bending moment, the unequal thickness steel pipe 1 is provided with a thick cross section 13 only in a range over a part in the pipe circumferential direction, as shown in FIGS. You may use what was

  In addition, when using the unequal thickness steel pipe 1 having a tapered shape from the thin cross section 11 to the thick cross section 13, the maximum wall thickness is applied to a portion where the influence of external factors such as bending moment and corrosion is particularly strong. It is preferable that the thick portion 13a is positioned so that the yield strength and the like can be exhibited particularly effectively with respect to these bending moments, and the design can be made more rationally.

  Further, the unequal thickness steel pipe 1 according to the present invention is used for the casing 31 in which a bending moment due to a static load or the like always acts in one direction from the upper side to the lower side of the unequal thickness steel pipe 1. In this case, as shown in FIG. 13, the unequal-thickness steel pipe 1 is provided in a range including a portion where the thick-walled cross-sectional portion 13 is displaced from the thin-walled cross-sectional portion 11 by approximately 180 ° in the pipe circumferential direction. It is preferable to fill with a curable filler 59 such as concrete to form a composite structure. In this case, the unequal-thickness steel pipe 1 is provided with the thick-walled cross-sectional portion 13 at a site where a large tensile stress is generated by a bending moment due to a static load or the like. Thereby, in the part where the tensile stress is greatly generated, the steel material that can effectively resist the tensile stress increases, and in the part where the compressive stress is largely generated, the filler 59 resists the compressive stress. It becomes possible to design more rationally.

  Note that filling the unequal-thickness steel pipe 1 with a time-hardening filler 59 such as concrete to form a composite structure means that the thick-walled cross-sectional portion 13 is replaced with the thin-walled cross-sectional portion 11 as shown in FIG. On the other hand, it is not intended only for the unequal-thickness steel pipe 1 provided in a range including a portion shifted by approximately 180 ° in the pipe circumferential direction. In addition to this, the non-uniform thickness steel pipe 1 that is the target of the composite structure may be, for example, as shown in FIGS. 1 to 6, and the positions in the circumferential direction of the thick section 13 and the thin section 11. It is not intended to be limited.

  Next, an example of a range in which the thick cross section 13 and the thin cross section 11 of the unequal thickness steel pipe 1 are provided will be described with reference to FIGS.

  In the example shown in FIG. 1A to FIG. 1C, the thick-walled cross-sectional portion 13 includes a central portion 15 for each of the upper half circumference portion and the lower half circumference portion in the pipe circumferential direction of the unequal thickness steel pipe 1. Is provided. In addition, the thin-walled cross-sectional portion 11 is provided between the thick-walled cross-sectional portions 13 provided for each half-circumferential portion, and more specifically, from the central portion 15 of each of the upper half-circumferential portion and the lower half-circumferential portion in the pipe circumferential direction. It is provided so as to be shifted by 90 °. From the thin section 11 to the central part 15 of each of the upper half circumference part and the lower half circumference part, it is formed in a taper shape so that the thickness continuously increases, and the maximum thickness part 13a is located in the central part 15 It is provided to do.

  2 (a), 2 (b) and FIG. 3, the thick cross section 13 is provided only in a range including the central portion 15 of the upper half circumference portion of the unequal thickness steel pipe 1 in the pipe circumferential direction. ing. Further, the thin-walled cross-sectional portion 11 is provided in a portion in the pipe circumferential direction other than the thick-walled cross-sectional portion 13. In the illustrated example, the thin-walled cross-sectional portion 11 is provided in all the lower half-circumferential portions of the unequal thickness steel pipe 1. From the thin-walled cross-sectional portion 11 to the central portion 15 of the upper half-circumferential portion, it is formed in a taper shape so that the thickness continuously increases, and the maximum thick portion 13a is located at the central portion 15. Yes.

  Further, in the example shown in FIG. 4, the thick cross-sectional portion 13 is provided in a range including the central portion 15 for each ¼ circumferential portion in the pipe circumferential direction of the unequal thickness steel pipe 1. Further, the thin-walled cross-sectional portion 11 is provided between the thick-walled cross-sectional portions 13 provided for each ¼ circumferential portion, and more specifically, from the central portion 15 of each ¼ circumferential portion in the pipe circumferential direction. It is provided so as to be shifted by 45 °. From the thin section 11 to the central portion 15 of each ¼ circumference portion, it is formed in a taper shape so that the thickness continuously increases, and the maximum thickness portion 13a is located in the central portion 15. Is provided.

  In the example shown in FIG. 5, the thin-walled cross-sectional portion 11 is formed on a part of the lower side of the unequal thickness steel pipe 1. Moreover, the thick cross-section part 13 is provided in the perimeter part of pipe circumference directions other than the thin cross-section part 11 of the unequal thickness steel pipe 1. FIG. It is formed in a taper shape so that the wall thickness continuously increases from the thin section 11 to a position shifted by 180 ° in the pipe circumferential direction, and the maximum thickness portion 13a is positioned at the position shifted by 180 °. Is provided.

  Further, in the example shown in FIG. 6, the thick cross section 13 is provided on all the upper ¼ circumferential portions of the unequal thickness steel pipe 1. Moreover, the thin cross-sectional part 11 is provided in all the remaining 3/4 circumference parts of the remainder of the unequal thickness steel pipe 1. FIG. A stepped portion 23a is provided from the thin cross-sectional portion 11 to the thick cross-sectional portion 13 so as to increase in thickness stepwise, and is formed in a stepped shape.

  Next, the example of the steel plate 20 used for the unequal thickness steel pipe 1 which concerns on this invention is demonstrated using FIGS.

  In the example shown in FIG. 1A, the unequal thickness steel pipe 1 is composed of four single-taper steel plates 21. The four single taper steel plates 21 are configured as a ¼ circumferential portion of the unequal thickness steel pipe 1.

  In the example shown in FIG. 1 (b), the unequal thickness steel pipe 1 is composed of two double tapered steel plates 21. The two tapered steel plates 21 are configured as half-circumferential portions on the upper side and the lower side of the unequal thickness steel pipe 1, respectively.

  In the example shown in FIG. 1 (c), the unequal thickness steel pipe 1 is composed of two central tapered steel plates 21. The two central tapered steel plates 21 are configured as half-circumferential portions on the left and right sides of the unequal thickness steel pipe 1, respectively.

  In the example shown in FIG. 2A, the unequal thickness steel pipe 1 is composed of two single tapered steel plates 21 and a single steel plate 20 having the same thickness. The two single taper steel plates 21 are configured as a ¼ circumferential portion constituting the upper half circumferential portion of the unequal thickness steel pipe 1, and the single steel plate 20 having the same thickness is the unequal thickness steel pipe 1. It is configured as a lower half circumference.

  In the example shown in FIG. 2B, the unequal-thickness steel pipe 1 is composed of a single taper steel plate 21 and a single steel plate 20 having the same thickness. One taper steel plate 21 is configured as a semicircular portion on the upper side of the unequal thickness steel pipe 1, and one steel plate 20 having a uniform thickness is configured as a semicircular portion on the lower side of the unequal thickness steel tube 1. The

  In the example shown in FIG. 3, the unequal thickness steel pipe 1 is composed of one taper steel plate 21 and four steel plates 20 having the same thickness. One taper steel plate 21 is configured as a semicircular portion on the upper side of the unequal thickness steel pipe 1, and four steel plates 20 having a uniform thickness constitute a semicircular portion on the lower side of the unequal thickness steel tube 1. It is configured as a 1/8 round portion.

  In the example shown in FIG. 4, the unequal thickness steel pipe 1 is composed of four double tapered steel plates 21. The four taper steel plates 21 are configured as a ¼ circumferential portion of the unequal thickness steel pipe 1.

  In the example shown in FIG. 5, the unequal thickness steel pipe 1 is composed of one double tapered steel plate 21. One taper steel plate 21 is configured as the entire peripheral portion of the unequal thickness steel pipe 1.

  In the example shown in FIG. 6, the unequal thickness steel pipe 1 is composed of two differential thickness steel plates 23 and one steel plate 20 having the same thickness. The two differential thickness steel plates 23 are configured as a ¼ circumference portion constituting the upper half circumference portion of the unequal thickness steel pipe 1, and one steel plate 20 having an equal thickness is formed of the unequal thickness steel pipe 1. It is configured as a lower half circumference.

  In any of the examples, the peripheral end portions 20a of the steel plates 20 to be abutted with each other are adjusted to have the same thickness. Further, when the tapered steel plate 21 is used for the unequal thickness steel pipe 1, the gradient of the tapered steel plate 21 is expressed by, for example, a maximum of 10 (in terms of the change in thickness (mm) per 1 m in the direction parallel to the tapered steel plate 21. mm / m).

  As mentioned above, although the example of embodiment of this invention was demonstrated in detail, all the embodiment mentioned above showed only the example of actualization in implementing this invention, and these are the technical aspects of this invention. The range should not be construed as limiting.

DESCRIPTION OF SYMBOLS 1 Unequal-thickness steel pipe 3 Structure 11 Thin cross-section part 13 Thick cross-section part 13a Maximum thick part 15 Central part 20 Steel plate 20a Circumferential end part 21 Tapered steel plate 21a One end 21b Other end 21c Central part 23 Difference thickness steel plate 23a Step part 31 Steel frame 41 Bridge 42 Steel pipe main girder 43 Cross girder 44 Floor slab 45 Steel pipe pier 46 Upper structure 47 Overhang 48 Steel pipe pile 49 Concrete structure 50 Fixing member 51 Steel pipe sheet pile wall 52 Water area 53 Earth 54 Boundary part 55 Steel pipe sheet pile 56 Steel pipe body 57 Joint 58 Projected part 59 Time-hardening filler A direction (direction parallel to steel plate)
X Bridge axis direction Y Bridge axis orthogonal direction P Vertical direction Q Left and right direction

Claims (15)

A structure having a steel pipe installed as a housing,
The steel pipe is provided in a thin cross section provided in a part of the pipe circumferential direction, and a thick wall provided in a portion different in the pipe circumferential direction with respect to the thin cross section and formed thicker than the thin cross section. An unequal thickness steel pipe comprising an unequal thickness steel pipe provided with a cross-sectional portion, wherein the thick-walled cross-section portion is located at a predetermined position according to the installation location of the steel pipe. Structure using The steel pipe is used as a casing in which a bending stress degree generated with respect to a part in the pipe circumferential direction is larger than other parts in the pipe circumferential direction, and the thick wall is formed in a part where the bending stress degree is generated larger than other parts. The structure using the unequal thickness steel pipe according to claim 1, wherein the structure is installed so that a cross-sectional portion is located. The steel pipe is used as a steel pipe main body having a steel pipe sheet pile wall placed at the boundary between the water area and the soil, and is installed so that the thick-walled cross section is located at the most protruding part on the water area side of the steel pipe main body The structure using the unequal thickness steel pipe according to claim 1. The steel pipe is formed by bending at least one steel plate including a tapered steel plate or a differential thickness steel plate having the thin-walled cross-section portion and the thick-walled cross-section portion, and the bent steel plate abuts the peripheral end portion to form a cylinder. The structure using the unequal thickness steel pipe according to any one of claims 1 to 3, wherein the circumferential end portions of the steel plates arranged in a shape and joined together are joined to each other. The thick cross section is provided in a range including the central portion for each half circumferential portion in the pipe circumferential direction,
The structure using an unequal-thickness steel pipe according to any one of claims 1 to 4, wherein the thin-walled cross-sectional portion is provided between the thick-walled cross-sectional portions provided for each of the semicircular portions. body. The thick-walled cross-sectional portion is provided in a range including the central portion for every ¼ circumferential portion in the pipe circumferential direction,
The unequal-thickness steel pipe according to any one of claims 1 to 4, wherein the thin-walled cross-section portion is provided between the thick-wall cross-section portions provided for each of the ¼ circumferential portions. The structure used. The thick cross section is provided only in a range including the central portion of the semicircular portion in the pipe circumferential direction,
The structure using an unequal-thickness steel pipe according to any one of claims 1 to 4, wherein the thin-walled cross-sectional portion is provided in a portion in a pipe circumferential direction other than the thick-walled cross-sectional portion. . The structure using an unequal thickness steel pipe according to any one of claims 1 to 7, wherein the unequal thickness steel pipe is filled with a time-hardening filler. The structure using the unequal thickness steel pipe according to any one of claims 4 to 8, wherein the unequal thickness steel pipe is formed by welding peripheral ends of the abutted steel plates. . A thin cross-sectional portion provided in a part of the pipe circumferential direction;
An unequal-thickness steel pipe, comprising: a thick-walled cross-section portion provided at a different location in the pipe circumferential direction with respect to the thin-walled cross-section portion and formed thicker than the thin-walled cross-section portion. At least one or more steel plates including a tapered steel plate or a differential thickness steel plate having the thin-walled cross-section portion and the thick-wall cross-section portion are bent, and the bent steel plate is disposed in a cylindrical shape by abutting the peripheral end portion. The unequal-thickness steel pipe according to claim 10, wherein the circumferential end portions of the abutted steel plates are joined to each other. The thick cross section is provided in a range including the central portion for each half circumferential portion in the pipe circumferential direction,
The unequal-thickness steel pipe according to claim 10 or 11, wherein the thin-walled cross-sectional portion is provided between thick-walled cross-sectional portions provided for each half-circumferential portion. The thick-walled cross-sectional portion is provided in a range including the central portion for every ¼ circumferential portion in the pipe circumferential direction,
The unequal-thickness steel pipe according to claim 10 or 11, wherein the thin-walled cross-sectional portion is provided between thick-walled cross-sectional portions provided for each of the ¼ circumferential portions. The thick cross section is provided only in a range including the central portion of the semicircular portion in the pipe circumferential direction,
The unequal-thickness steel pipe according to claim 10 or 11, wherein the thin-walled cross-sectional portion is provided in a portion in the pipe circumferential direction other than the thick-walled cross-sectional portion. The unequal-thickness steel pipe according to any one of claims 11 to 14, wherein peripheral ends of the abutted steel plates are joined by welding.

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