Description

REINFORCING APPARATUS FOR END PART OF UNDERGROUND-STRUCTURE USING CORRUGATED MULTI PLATE AND REINFORCING METHOD USING THE SAME

Technical Field

[1] The present invention relates to an end reinforcement for reinforcing end parts of a corrugated multi plate underground- structure and a reinforcing method using the same, and more particularly, to a method for reinforcing end parts of a corrugated multi plate underground-structure by mounting reinforcements on a backfiller of the corrugated multi plate underground-structure. Background Art

[2] A corrugated multi plate underground- structure is to increase rigidity of a steel plate of a rolled structural steel sheet through a corrugated molding and make backfill soil and the structure resist to an external applied load to thereby reduce a load applied to the structure. Such a corrugated multi plate underground- structure can reduce a construction period and construction expenses more than conventional concrete structures since it has a modulus of section, which is ten to thirty times as large as that of a general steel plate of the same thickness due to an application of a corrugated section, increases a resistance to corrosion due to an enhancement of durability by hot galvanizing, and can be constructed on the spot through a simple bolt-joint and a backfilling work.

[3] The corrugated multi plate underground-structure is still lower in endurable load than the conventional rigid structure having the same inner diameter when a load is applied thereto since the corrugated multi plate structure is dynamically very thin. However, the corrugated multi plate underground-structure has the same load-carrying capacity as the rigid structure or more load-carrying capacity than the rigid structure since it is a soft structure and supports the load using a transformation of a steel plate by a vertical earth pressure. A horizontal transformation of the steel plate by the vertical soil pressure applies pressure to backfill soil of a face wall portion of the steel plate to thereby cause a lateral earth pressure, and such a lateral earth pressure serves to support the vertical earth pressure. Accordingly, the corrugated multi plate underground-structure can endure a great external pressure even though it is a thin sheet since a bending moment hardly acts and only an axial force acts.

[4] However, in case where a bell mouth (cylindrically cut portion) is applied to an end part of the structure, it is easy to cause a displacement by the lateral earth pressure since the bell mouth part is in a cantilever structure. Furthermore, if the backfilling is

carried out in a state where the end part is restricted by face walls, it causes an additional maintenance fee and a lowering of the beauty of the outward appearance due to a crack in the face walls since the steel plate rises.

[5] As a conventional method for reinforcing the ends of the corrugated multi plate underground-structure, to which the bell mouth is applied, or, which is restricted by the face walls, as shown in FIG. 8, there is a method that metal channels 110 are axially bonded to the end part of a corrugated multi plate underground- structure 100 in a stratified form to thereby reinforce rigidity of the corrugated multi plate structure. However, the reinforcing method for reinforcing rigidity of the corrugated multi plate structure has a problem in that an additional maintenance fee is caused and construction expenses are increased due to its insignificant reinforcing performance. Disclosure of Invention Technical Problem

[6] Accordingly, the present invention has been made in an effort to solve the above- mentioned problems occurring in the prior arts, and it is an object of the present invention to provide an end reinforcement for reinforcing end parts of a corrugated multi plate underground- structure and a reinforcing method using the same, which can provide a good reinforcement efficiency through an easy construction and reduce maintenance fees through a better reinforcing performance.

[7] Another object of the present invention is to provide an end reinforcement for reinforcing end parts of a corrugated multi plate underground-structure and a reinforcing method using the same, which can adjust an angle according to a curvature of the corrugated multi plate structure, provide a good reinforcement efficiency through an easy construction and reduce maintenance fees through a better reinforcing performance. Technical Solution

[8] To achieve the above objects, In an aspect of the present invention, the present invention provides an end reinforcement for reinforcing end parts of a corrugated multi plate underground- structure includes: a first reinforcement aligned at right angles to an axial direction of the corrugated multi plate structure and constructed of a strip form, which has a length larger than a width; and a plurality of second reinforcements inclinedly joined to the first reinforcement.

[9] In another aspect of the present invention, the present invention provides a method for reinforcing end parts of a corrugated multi plate underground- structure including the steps of: (a) installing foundation structures at a predetermined interval, and assembling the corrugated multi plate structure in such a way that both circumferential end parts of the corrugated multi plate structure, which has the bell mouth applied to at

least one end part thereof in an axial direction, are fixed to the foundation structures; (b) fixing a plurality of reinforcement- fixing angles to the bell mouth part of the corrugated multi plate structure in a longitudinal direction; (c) joining an end reinforcement, which comprises a first reinforcement and a plurality of second reinforcement, to each of the reinforcement-fixing angles in such a way as to be aligned at right angles to an axial direction of the corrugated multi plate structure, the first reinforcement being aligned at right angles to an axial direction of the corrugated multi plate structure and constructed of a strip form, which has a length larger than a width, each of the second reinforcements being inclinedly joined to the first reinforcement;

(d) carrying out backfilling in such a way that the end reinforcements are buried; and

(e) repeatedly carrying out the steps (b) to (d) up to the upper end portion of the bell mouth of the corrugated multi plate structure.

[10] In a further aspect of the present invention, the present invention provides a method for reinforcing end parts of a corrugated multi plate underground- structure including the steps of: (a) installing foundation structures at a predetermined interval, assembling the corrugated multi plate structure in such a way that both circumferential end parts of the corrugated multi plate structure are fixed to the foundation structures, and mounting face walls on both longitudinal end parts of the corrugated multi plate structure; (b) fixing a plurality of reinforcement- fixing angles on portions of the corrugated multi plate structure, which are in contact with the face walls, in a longitudinal direction; (c) joining an end reinforcement, which comprises a first reinforcement and a plurality of second reinforcement, to each of the reinforcement- fixing angles in such a way as to be aligned at right angles to an axial direction of the corrugated multi plate structure, the first reinforcement being aligned at right angles to an axial direction of the corrugated multi plate structure and constructed of a strip form, which has a length larger than a width, each of the second reinforcements being inclinedly joined to the first reinforcement; (d) carrying out backfilling in such a way that the end reinforcements are buried; and (e) repeatedly carrying out the steps (b) to (d) up to the upper end part of the corrugated multi plate structure.

Advantageous Effects

[11] The end reinforcement for reinforcing end parts of a corrugated multi plate underground-structure according to the present invention can provide good reinforcement efficiency through an easy construction and reduce maintenance fees through a better reinforcing performance.

[12] Furthermore, the present invention can minimize a transformation by reducing earth pressure acting to the bell mouth part of a cantilever structure by virtue of the reinforcement spreading on the backfill soil like a root of a tree.

[13] Moreover, the present invention can minimize a crack of the face wall, which may occur due to rising of the steel plate during backfilling, by reinforcing the backfill soil since the reinforcement is mounted in such a way as to spread on the backfill soil like the root of the tree. Brief Description of Drawings

[14] FIG. 1 is a perspective view of an end reinforcement according to a first preferred embodiment of the present invention.

[15] FIG. 2 is a perspective view of a modification of the end reinforcement according to the first preferred embodiment of the present invention.

[16] FIG. 3 is a perspective view of an end reinforcement according to a second preferred embodiment of the present invention.

[17] FIG. 4 is a perspective view showing a state where the end reinforcement according to the second preferred embodiment is joined to a corrugated multi plate structure.

[18] FIG. 5 is a schematically sectional view showing a sequence of a method for reinforcing end parts of the corrugated multi plate structure using the end reinforcement.

[19] FIG. 6 is a partially plan view showing a state where the end reinforcement is reinforced on end parts of the corrugated multi plate structure.

[20] FIG. 7 is an enlarged view showing a state where the end reinforcement is joined to the corrugated multi plate structure.

[21] FIG. 8 is a perspective view showing a conventional method for reinforcing end parts of a corrugated multi plate structure. Best Mode for Carrying out the Invention

[22] Hereinafter, preferred embodiments of the invention will be explained in detail with reference to the accompanying drawings. In the drawings, like elements are denoted by like reference characters. Details on well-known elements and functions will be omitted.

[23] FIG. 1 is a perspective view of an end reinforcement according to a first preferred embodiment of the present invention.

[24] Referring to FIG. 1, the end reinforcement 10 according to the first preferred embodiment includes a first reinforcement 11, and a plurality of second reinforcements 12 inclinedly joined to the first reinforcement 11.

[25] The first reinforcement 11 is constructed of a strip form, which has a length larger than a width, and is aligned at right angles to an axial direction of a corrugated multi plate structure. It is preferable that the first reinforcement 11 is constructed of a steel strip, but the first reinforcement 11 may be constructed of a fiber reinforced plastic strip. In case where the first reinforcement 11 is made of steel material, it is necessary to take necessary measures against corrosion, and as an example, hot galvanizing may

be considered. A ratio of the entire length to the width/thickness of the first reinforcement 11 may be decided by the structure calculation in consideration of a backfill length of the corrugated multi plate structure.

[26] The second reinforcements 12 are inclinedly mounted on the first reinforcement 11.

The second reinforcements 12 may be constructed of a bar shown in FIG. l(a) or a strip shown in FIG. l(b). The second reinforcements 12 may be made of steel material, plastic or fiber reinforced plastic. In case where the second reinforcements 12 are made of the steel material, it is necessary to take necessary measures against corrosion like the first reinforcement, and as an example, hot galvanizing may be considered. Means to bond the second reinforcements 12 to the first reinforcement 11 may be properly selected in consideration of materials of the reinforcements. The second reinforcements 12 can be bonded to the first reinforcement 11 by welding or bolting in case where all of the first and second reinforcements are made of the steel material, but can be bonded to the first reinforcement 11 using adhesives in case where the first and second reinforcements are made of plastic. In FIG. l(a), the first reinforcement 11 has a plurality of holes perforated at regular intervals in a longitudinal direction, and each of the second reinforcements 12 is bent at an end part thereof and the bent end part of the second reinforcement 12 is inserted into each hole of the first reinforcement 11.

[27] As described above, since the plural second reinforcements 12 are joined to the first reinforcement 11 in such a way as to spread like a root of a tree, it can reduce the length of the first reinforcement 11 more than a case where only the first reinforcement

11 reinforces the structure, and enhance pull-out resistance by increasing a friction force to the backfill soil. As shown in the drawing, the second reinforcements 12 may be bonded to both sides of the first reinforcement 11 or just one of the sides of the first reinforcement 11. An installation angle and the number of the second reinforcements

12 can be determined by the structure calculation. Accordingly, the angle that the second reinforcements 12 are bonded to the first reinforcement 11 is not restricted to the illustrated embodiment, but the second reinforcements 12 may be bonded to the first reinforcement 11 within a range of angles of 30 degrees to 150 degrees to the first reinforcement 11. In case where the second reinforcements 12 are bonded to the first reinforcement 11 at an angle of more than 90 degrees, for example, at an angle of 150 degrees, larger pull-out resistance may be expected. The second reinforcements 12 may be mounted on the entire length of the first reinforcement 11, but may not be mounted on a part of the first reinforcement 11, which is located in a non-compacted zone of the backfill soil as shown in FIG. 1.

[28] FIG. 2 is a perspective view of a modification of the end reinforcement according to the first preferred embodiment of the present invention. [29] First, as shown in FIG. 2(a), an anchor plate 13 is mounted on a free end portion of

each of the second reinforcements 12, which are inclinedly mounted on the first reinforcement 11. Since the anchor plates 13 are mounted on the second reinforcements 12, the friction force, which has a great influence on coherence between the backfill soil and the reinforcements, can be increased. The anchor plates 13 may be made of steel material, plastic, or fiber reinforced plastic like the second reinforcements 12, or can be selectively applied to the second reinforcements 12 through one of known bonding methods in consideration of the material of the second reinforcements 12 according to the material of the anchor plates 13.

[30] In the meantime, if the surface of the reinforcement is rough, since it may generate a frictional resistance better than a smooth surface of the reinforcement, it is preferable that the first reinforcement has a uneven surface or a scratched surface to make the rough surface. Accordingly, as shown in FIG. 2(b), the present invention has the first reinforcement 11 of a corrugated strip form to thereby generate better frictional resistance.

[31] FIG. 3 is a perspective view of an end reinforcement according to a second preferred embodiment of the present invention, and FIG. 4 is a perspective view showing a state where the end reinforcement according to the second preferred embodiment is joined to a corrugated multi plate structure.

[32] As shown in FIG. 3, in the second preferred embodiment, an end reinforcement 10a includes a connection part 111, a reinforcing part 113, and a twisted part 112 formed in such a way that a strip is twisted once at an angle of 90 degrees. That is, the end reinforcement 10a includes the connection part 111, which is parallel to a circumferential direction of the corrugated multi plate structure, the reinforcement part 113 forming a perpendicular face to the connection part 111, and the twisted part 112 for perpendicularly connecting the connection part 111 and the reinforcement part 113 with each other.

[33] The end reinforcement has the structure as described above, and as shown in FIG. 4, when the end reinforcement is joined to a side of the corrugated structure 100 assembled in such a way as to have a predetermined curvature, such as a circle or an oval, the reinforcement part 113 of the end reinforcement 10a can be mounted in such a way as to be leveled corresponding to the curvature of the corrugated multi plate structure 100. That is, while the conventional reinforcement constructed of the steel strip without the connection part and the twisted part has the problem in that the reinforcement rises upwardly at a portion joined with the corrugated multi plate structure, the reinforcement part 113 of the end reinforcement according to the present invention can be mounted in such a way that the entire length of the reinforcement part 113 is always at a level since a mounting angle can be changed correspondingly to the curvature of the corrugated multi plate structure by virtue of the connection part 112,

which is parallel to the circumferential direction of the corrugated multi plate structure. If the reinforcement is not at a level with the corrugated multi plate structure, it causes a problem that the reinforcement cannot effectively show the pull-out resistance. However, the reinforcement according to the present invention shows an improved resistance performance against pull-out since it is mounted at a level.

[34] Hereinafter, a method for reinforcing the end parts of the corrugated multi plate underground-structure using the end reinforcement according to the present invention will be described as follows.

[35] FIG. 5 is a schematically sectional view showing a sequence of a method for reinforcing end parts of the corrugated multi plate structure using the end reinforcement, FIG. 6 is a partially plan view showing a state where the end reinforcement is reinforced on end parts of the corrugated multi plate structure, and FIG. 7 is an enlarged view showing a state where the end reinforcement is joined to the corrugated multi plate structure.

[36] A case where a bell mouth is applied to the end part of the corrugated multi plate structure will be described.

[37] First, install foundation structures 200 at a predetermined interval, complete the corrugated multi plate structure 100 in such a way as to fix both circumferential end parts of the corrugated multi plate structure 100, which has the bell mouth applied to at least one end part thereof in an axial direction, to the foundation structures 200 and assemble the remaining parts (Step (a), see FIG. 5(a)). Here, since construction of the foundation structures 200 and assembly of the corrugated multi plate structure 100, which has the bell mouth at one end part thereof, are the same as an installation method of the known conventional corrugated multi plate structure, detailed descriptions thereof will be omitted.

[38] Next, fix a plurality of reinforcement-fixing angles 300 to the bell mouth of the corrugated multi plate structure 100 in a longitudinal direction (Step (b)). The reinforcement-fixing angles 300 are provided to fix the first reinforcement 11 to the corrugated multi plate structure 100. In the present invention, the reinforcement- fixing angles 300 are mounted on the end part of the corrugated multi plate structure 100, namely, on the outer surface of the end part joined to the bell mouth part (or a face wall, which will be described later). Each of the reinforcement- fixing angles 300 includes at least one hole formed for a bolt-joining with the corrugated multi plate structure 100 and at least one hole formed for a bolt-joining with the first reinforcement 11 (see FIG. 7).

[39] Next, join the reinforcements 10 and 10a to the reinforcement-fixing angles 300 in such a way as to be aligned at right angles to an axial direction of the corrugated multi plate structure 100 (Step (c), see FIG. 5(b)). The end reinforcement is joined to each of

the fixing angles 300 through a hole perforated at an end portion of the first reinforcement 11 via a bolt (see FIGS. 6 and 7).

[40] Next, carry out backfilling in such a way that the reinforcements 10 or 10a are buried

(Step (d)). In this instance, backfill also the central part of the corrugated multi plate structure together with the end part. Furthermore, repeatedly carry out the steps (b) to (d) up to the upper end portion of the bell mouth of the corrugated multi plate structure to thereby complete the reinforcement of the end part of the corrugated multi plate structure (see FIG. 5(c)).

[41] That is, in the present invention, since the reinforcement is completely installed when the reinforcements 10 or 10a are bolt-joined to the angles 300 after the reinforcement- fixing angles 300 are bolt-joined to the corrugated multi plate structure 100, it has little influence on the backfilling process after assembly of the corrugated multi plate structure, and hence, there is no problem of a delay of a construction period caused by the reinforcement of the end part. Moreover, the present invention can minimize a transformation of the corrugated multi plate structure since the second reinforcements 12, which spread on the backfill soil like the root of the tree, reduces the earth pressure acting to the bell mouth part of the cantilever structure.

[42] In the meantime, a case where the face walls are mounted on the end parts of the corrugated multi plate structure will be described.

[43] Install foundation structures at a predetermined interval, complete the corrugated multi plate structure in such a way as to fix both circumferential end parts of the corrugated multi plate structure to the foundation structures and assemble the remaining parts, and then, mount the face walls on both longitudinal end parts of the corrugated multi plate structure (Step (a)). Fix a plurality of reinforcement- fixing angles on portions of the corrugated multi plate structure, which are in contact with the face walls, in a longitudinal direction (Step (b)). Join the end reinforcement to each of the reinforcement-fixing angles in such a way as to be aligned at right angles to an axial direction of the corrugated multi plate structure (Step (c)). After that, carry out backfilling in such a way that the end reinforcements are buried (Step (d)). Furthermore, repeatedly carry out the steps (b) to (d) up to the upper end part of the corrugated multi plate structure. Here, since construction of the foundation structures 200, assembly of the corrugated multi plate structure 100, and installation of the face walls are the same as an installation method of the known corrugated multi plate structure, detailed descriptions thereof will be omitted.

[44] In case where the backfilling is carried out in a state where the end parts of the corrugated multi plate structure are restricted by the face walls, the prior arts have a problem in that a maintenance fee is additionally required due to a crack of the face walls since the steel plate rises to thereby deteriorate the outward appearance.

However, the present invention can minimize a crack of the face walls caused by the rising of the steel plate when backfilling is carried out by reinforcing the backfill soil since the end reinforcement is installed in such a way as to spread on the backfill soil like the root of the tree.

[45] While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. Industrial Applicability

[46] As described above, the present invention can effectively reinforce the end parts of the corrugated multi plate underground-structure, to which the bell mouth is applied, or, which is restricted by the face walls.