JP2008133591A - Water cut-off device for expansion gap and sheathing board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the efficiency of expansion gap treating work in the construction work of mounting an extending and contracting device in an expansion gap, and to improve the strength for supporting the extending and contracting device. <P>SOLUTION: Anchor bolts 22A (22B) are attached to an anchor 26A (26B) provided on a floor system 25A (25B) in a box removing part 24A (24B) formed in an end part of a bridge girder. Tips of the anchor bolts 22A (22B) project slightly into the expansion gap 20, and the sheathing board 11A (11B) is attached to the tips. The sheathing board 11A (11B) is composed of a sheathing board body 110A (110B) made of a hard material and a flexible part 111A (111B) made of a soft material. The flexible part 111A (111B) is obliquely extended from a lower side part of the sheathing board body 110A (110B). The flexible part 111A (111B) is pressed against a side wall in the end part of the bridge girder 21A (21B) forming the expansion gap 20 and adheres closely to the side wall in the end part where unevenness exists to prevent leakage of concrete when placing concrete. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to construction for installing a telescopic device between bridges or between a bridge and an abutment, and more particularly to a water stop device or a dam plate installed between the bridges at this time.

  When expansion devices (expansion joints) such as simple steel joints and rubber joints are provided between the bridge girders or between the bridge girders and the end of the abutment, the floor slab ends of the bridge girders facing each other and the parapet end of the abutment The part is boxed in advance, and after installing the expansion / contraction device on the boxed part, concrete is placed on the boxed part. When casting concrete, an inner mold is used to prevent leakage of concrete into the gap. As the inner mold, a method of sandwiching and fixing a panel between a member such as polystyrene foam inserted between the play and the wall surface of the end, or a stretchable member such as urethane foam is directly packed in the play to form a mold The method is known.

In addition, a structure is known in which a dam plate is disposed between the joint and the floor surface of the boxing portion to prevent leakage of concrete, and a water sealing rubber seal plate is attached to the dam plate (patent) References 1, 2). Moreover, although it is not a dam plate of concrete leak prevention, there also exists a structure which arrange | positions a fixing plate between the joint and the floor surface of a box extraction part, and attaches the dredging member for water stop (patent document 3).
Japanese Patent No. 3442362 JP-A-6-41909 Japanese Patent Laid-Open No. 5-86604

  However, the side wall part forming the gap is not necessarily flat, for example, the corner part formed by the side wall part and the floor surface of the boxing part is not necessarily a right angle, and the corner may be partially missing. Moreover, since the wall surface itself is wavy, there is unevenness. Therefore, when using the control panel, there is a problem that a gap is generated between the control panel and the side wall portion in the non-land portion, and the poured concrete is not pressed down and leaks in the play. In addition, when the gap is expanded after construction, there is a problem that the control panel or the polystyrene foam falls.

  On the other hand, when the elastic members such as urethane foam are packed in the play, it can follow the unevenness, but the elastic members such as urethane foam get into the box opening part and originally support the joint. There is a problem that the elastic member wraps around the lower joint, and the concrete does not reach the lower joint, resulting in insufficient load support and poor construction. In addition, when the dam plate is outside the joint, or when an elastic body such as a rubber sheet for secondary water stop is located at the lower part of the joint, the concrete lower part is not sufficiently supported.

  It is an object of the present invention to increase the efficiency of support processing of the expansion device and to improve the support strength of the expansion device in the construction for installing the expansion device between the spaces.

  The dam plate of the present invention is a dam plate used as a mold for placing concrete, and is provided on at least one side of the dam plate main body and the dam plate main body exhibiting rigidity as a flat plate during concrete pouring. It is characterized by having a flexible part capable of following the above.

  For example, the main body of the dam plate is made of a hard material, and the flexible part is made of a soft material. The dam plate is used as an inner formwork for placing concrete in the box opening part formed on both sides of the play, and the flexible part is pressed against the side wall surface forming the play space and follows the unevenness of the side wall surface. Close to the side wall surface. The flexible portion is provided obliquely with respect to the dam plate body, and preferably the angle of the flexible portion with respect to the dam plate body is 30 to 60 °. Moreover, it is preferable that the front-end | tip of a flexible part is formed in a taper shape.

  The dam plate further includes a pressing portion for sandwiching the sheet member for water stop between the gaps between the dam plate body and a curved portion that connects the pressing portion and the dam plate body. The curved portion is formed of, for example, a soft member, or is formed of, for example, a constricted portion and can be bent. Further, the curved portion is formed of a hard member or a soft member, and is molded in a curved shape in advance.

  The water stop device of the present invention is a water stop device attached between the play and includes a seat portion, a pair of weir plate portions, and a flexible portion, and both long side end portions of the sheet portion are provided in each of the weir plate portions. The sheet portion and the flexible portion are connected to each other, and the dam plate portion is formed from a hard material. The sheet portion, the dam plate portion, and the flexible portion are integrally formed.

  The flexible portion extends obliquely outward from one side of each of the pair of dam plates, and the angle formed by the flexible portion and the dam plates is, for example, 30 to 60 °. Moreover, it is preferable that a sheet | seat part and a flexible part are integrally shape | molded from the same raw material.

  As described above, according to the present invention, it is possible to improve the efficiency of the gap processing work and to improve the support strength of the expansion / contraction apparatus in the construction for installing the expansion / contraction apparatus between the gaps.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a part of a weir plate and a water stop device according to a first embodiment installed between bridges or between a bridge and an abutment. 2 is a side view of the dam plate and the water stop device shown in FIG. 1. FIG. 3 is a side view of the dam plate and the water stop device shown in FIGS. The installed state (state before placing concrete) is shown as a side sectional view.

  In the present embodiment, the water stop device 10 is made of a rubber sheet (sheet member) (hereinafter referred to as a water stop rubber), and the water stop rubber 10 extends in the width direction of the bridge girders 21A and 21B in the gap 20 and bridge girder. Water leakage from the gap 20 between 21A and 21B is prevented. The waterstop rubber 10 is a long rubber sheet bent into a U shape in the width direction, and both long side edges 10A and 10B are attached to the weir plates 11A and 11B, respectively.

  The dam plates 11A and 11B extend in the direction toward the width of the bridge beams 21A and 21B, and a plurality of mounting holes are provided at predetermined intervals in the width direction. Anchor bolts 22A and 22B arranged at predetermined intervals in the width direction of the bridge beams 21A and 21B are inserted into the mounting holes, respectively. Further, the anchor bolts 22A and 22B are attached with the long side ends 10A and 10B of the water blocking rubber 10 in which attachment holes are formed corresponding to the anchor bolts 22A and 22B. Further, holding plates 23A, 23B extending along the width of the bridge beams 21A, 21B are attached to the anchor bolts 22A, 22B. In addition, attachment holes corresponding to the anchor bolts 22A and 22B are formed in the holding plates 23A and 23B, similarly to the barrier plates 11A and 11B.

  That is, after the nut 220 is attached to each anchor bolt 22A, 22B, the barrier plate 11A (11B), the end portion 10A (10B) of the water blocking rubber 10 and the presser plate 23A (23B) are attached in this order. Finally, each member is sandwiched and fixed between the nuts 220 and 221 by the nut 221. The positions of the barrier plate 11A (11B), the end portion 10A (10B) of the water blocking rubber 10 and the pressing plate 23A (23B) can be adjusted by the position of the nut 220.

  The anchor bolts 22A and 22B are welded and fixed to anchors 26A and 26B embedded in the floor surfaces 25A and 25B of the box opening portions 24A and 24B formed at the end portions of the floor slabs of the bridge girders 21A and 21B. The anchor bolts 22 </ b> A and 22 </ b> B are arranged along the axis of the bridge beam and extend slightly toward the gap 20.

  Further, a simple steel joint 30 made of, for example, a pair of finger plates 30A, 30B is attached above the anchors 26A, 26B, and a urethane foam 27 filling, for example, a gap is filled on the water stop rubber 10. .

  In the present embodiment, two nuts 220 and 221 are used for the anchor bolt 22A (22B), and the weir plate 11A (11B), the water blocking rubber 10 and the pressing plate 23A (23B) are interposed between the nuts 220 and 221. Each member is attached to the anchor bolts 22 </ b> A and 22 </ b> B by pinching. However, for example, the nut 221 may be replaced with the bolt head of the anchor bolt 22 </ b> A (22 </ b> B) and each member may be fixed between the bolt head and the nut 220. In this case, as shown in FIG. 2, after the members are assembled to the anchor bolts 22A and 22B, the anchor bolts 22A and 22B are attached to the anchors 26A and 26B embedded in the floor surfaces 25A and 25B by means such as welding. It is done.

  As shown in FIGS. 1 to 3, the dam plate 11A (11B) includes a dam plate body 110A (110B) and a flexible portion 111A (111B). The dam plate body 110A (110B) is made of, for example, a plate-like member having a certain rigidity, and prevents the concrete from flowing out without being deformed when the concrete is placed. For example, a hard material is used for the weir plate body 110A (110B). Examples of the hard material include steel plates (SUS, SS, SUP, etc.), hard rubber (CR, EPT, etc. having a hardness A70 or higher in JISK6253), and hard resins (hard vinyl chloride, PP, etc.). On the other hand, the flexible portion 111A (111B) is made of a flexible plate member that can follow and adhere to unevenness such as unevenness. For example, a soft material is used for the flexible portion 111A (111B). Examples of the soft material include soft rubber (such as CR and EPT having a hardness of A70 or less) and soft resin (such as soft vinyl chloride and TPO). Also. A thin steel plate (SUS, SUP, etc.) can also be used for the flexible portion 111A (111B).

  The flexible portion 111A (111B) is a member provided below the dam plate body 110A (110B) along the longitudinal direction of the dam plate 11A (11B). For example, the lower end of the dam plate body 110A (110B) It extends from the part, and its tip is formed into a tapered shape, for example. Further, the flexible portion 111A (111B) is attached to the dam plate body 110A (110B) at an angle, and the side cross section of the dam plate 11A (11B) has a “he” shape. As shown in FIG. 2, when the inclination angle of the flexible portion 111A (111B) with respect to the surface of the main body 110A (110B) is θ, θ is set in the range of 0 to 90 °, preferably 30 to 60 ° is set. The dam plates 11A and 11B are arranged so that the flexible portions 111A and 111B project outward in the clearance 20 to form a “C” shape.

  The barrier plate 11A (11B) and the waterstop rubber 10 may be configured with the length of each joint as a unit in the width direction, for example, but may be integrated over the entire width, and the unit is arbitrary. is there.

  FIG. 4 shows an example in which the still water rubber 10 and the weir plates 11A and 11B of this embodiment are combined with a steel vertical joint 40 using a corrugated steel plate. Also in this case, the configuration relating to the attachment of the water blocking rubber 10 and the weir plates 11A and 11B is the same as the example shown in FIG. Moreover, the example which combined the still water rubber 10, the dam boards 11A and 11B, and the rubber joint 70 of this embodiment is shown in FIG. In the example of FIG. 5, a state in which the concrete placement to the box opening portion is finished and the rubber joint 70 is attached is shown. In addition to the anchors 26A and 26B to which the anchor bolts 22A and 22B for the dam plates 11A and 11B are fixed, anchors 26C and 26D are respectively embedded in the floor surfaces 25A and 25B. Anchor bolts 71A and 71B for attaching the rubber joint 70 are fixed.

  In addition, the combination of the water stop rubber 10, the dam plates 11A and 11B and the expansion / contraction device (joint) of the present embodiment is not limited to the present embodiment, and combinations with any expansion / contraction device are possible.

  Next, with reference to FIG. 6, the function of the weir plate 11A (11B) in this embodiment is demonstrated. FIG. 6 is an enlarged side sectional view showing the relationship between the dam plate 11A and the bridge girder 21A. However, since the same applies to the dam plate 11B and the bridge girder 21B, the relationship between the dam plate 11A and the bridge girder 21A is shown here. Only explained.

  Generally, unevenness exists in the end side wall 210 of the bridge girder 21A. In FIG. 6, the unevenness which exists in the edge part side wall 210 is typically shown with a continuous line and a broken line. That is, in FIG. 6, in the end side wall 210, cross sections corresponding to two positions having different surface heights are drawn with one solid line and the other with a broken line.

  Since the flexible portion 111 </ b> A projects toward the end side wall 210, the tip thereof is pressed against the end side wall 210. At this time, since the flexible portion 111A is formed of a soft material, the flexible portion 111A is deformed following the height of the surface of the end side wall 210, and is changed to the side of each end side wall 210 according to the shape of the end side wall 210. Closely close to the wall. That is, at the position of the end side wall 210 drawn by a solid line, the flexible part 111A abuts on the side wall surface as shown by being shaded, and for the position of the end side wall 210 drawn by a broken line, It abuts on the side wall surface as depicted by the broken line.

  As described above, when placing concrete, the flexible body having flexibility that can be deformed by following the unevenness from the main body having sufficient rigidity to maintain the shape (for example, the shape as a flat plate). By extending the section diagonally and forming the cross section of the weir plate in the shape of a “he”, the flexible part follows the unevenness of the end face of the side wall forming a gap and closely contacts the wall surface For this reason, the concrete does not leak through the uneven land when the concrete is placed in the box opening portion. That is, according to the weir plate of the present embodiment, it is possible to provide an inner mold that can follow the unevenness between the play. In particular, in this embodiment, since the tip of the flexible part is tapered, the adaptability of the flexible part to unevenness is further improved.

  Further, when the dam plate of the present embodiment is used, it is not necessary to place the dam plate in the box opening part, so that the concrete can be sufficiently placed at the position where the expansion device is supported. The strength can be improved. In addition, by using a material that is resistant to deterioration as the material of the dam plate, it can be buried, so the lower concrete of the expansion and contraction device will be reinforced by the anchor to which the dam plate is attached. Can be increased.

  In addition, although the weir board of 1st Embodiment was used with the water stop rubber for secondary water stop, it can also be used independently. In this case, the barrier plate may be fixed to the anchor bolt by welding.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a side view showing a state where the waterproof rubber and the dam plate of the second embodiment are attached to the anchor bolt, and FIG. 8 is a side sectional view of the dam plate of the second embodiment. In addition, about the structure similar to 1st Embodiment, the description is abbreviate | omitted using the same referential mark.

  As shown in FIGS. 7 and 8, the dam plate 50A (50B) of the second embodiment includes a pressing portion 112A (112B) in addition to the dam plate body 110A (110B) and the flexible portion 111A (111B). A curved portion 113A (113B) is provided. The curved portion 113A (113B) is a member that connects the dam plate body 110A (110B) and the holding portion 112A (112B). For example, the curved portion 113A (113B) is made of a soft material similar to the flexible portion 111A (111B). Can use the same material as the flexible part 111A (111B). On the other hand, the material of the holding portion 112A (112B) is not limited, but it is made of, for example, a hard material, and the same material as the dam plate main body 110A (110B) can be used.

  As shown in FIG. 7, when the anchor bolt 22A (22B) is mounted, the curved portion 113A (113B) of the barrier plate 50A (50B) is bent, and the barrier plate main body 110A (110B) and the holding portion 112A (112B). 10A (10B) of the long side of the water-stopping rubber 10 is sandwiched therebetween. In other words, the holding portion 112A (112B) is also provided with a mounting hole for passing through the anchor bolt 22A (22B). After each nut 22 is attached to each anchor bolt 22A (22B), the weir plate 11A (11B), the long side end portion 10A (10B) of the water blocking rubber 10, and the holding portion 112A (112B) are mounted in this order, and finally each member is sandwiched between the nuts 220 and 221 by the nut 221. Fixed. Accordingly, the holding portion 112A (112B) plays the role of the holding plate 23A (23B) in the first embodiment, and the upper portion of the long side end portion 10A (10B) of the water blocking rubber 10 is a curved portion 113A (113B). Covered by.

  As described above, according to the dam plate of the second embodiment, the same effect as that of the first embodiment can be obtained, and the upper part of the long-side end portion of the water-stopping rubber is covered with the curved portion. Water from between the plate body and the holding plate can be surely prevented from leaking. Moreover, since the pressing plate and the barrier plate are integrated, the number of parts can be reduced and the mounting efficiency is also improved.

  FIG. 9 shows a first modification of the second embodiment. In the second embodiment, a member made of a soft material is used for the curved portion. However, in the weir plate 60B (60A) of this modification, the curved portion 114B (114A) is configured as a constricted portion. In other words, in this modification, the bending portion 114B (114A) is formed thin to increase its flexibility and bendable when worn. Therefore, in the first modified example, the same effects as those of the second embodiment can be obtained, and the weir plate body, the curved portion, and the pressing portion can be made of, for example, the same material, so that the manufacturing cost can be kept low. It becomes.

  FIG. 10 shows a second modification of the second embodiment. In the second modification, the dam plate main body 80B (A), the bending portion 115B (115A), and the holding portion 112B (112A) are integrally formed from the same material, and the bending portion 115B (115A) has a curved shape from the beginning. Molded with. The degree of bending is set so that the gap between the weir plate main body 80B (A) and the pressing portion 112B (112A) matches the thickness of the waterproof rubber. According to the configuration of the second modified example, the same effect as that of the first modified example can be obtained, and since the curved portion is curved in advance, it is not necessary to bend the curved portion at the time of assembly, and the efficiency of the assembly work is increased. be able to.

  In the first and second embodiments and the modifications thereof, the flexible portion is made of a soft material, and the dam plate body and the holding portion are made of a hard material, but the entire dam plate is made of the same material. And by adjusting the thickness and shape, it is also possible to give rigidity to the barrier plate body and the pressing part and to give flexibility to the flexible part. That is, the thickness of the dam plate body is set to a thickness or shape that is sufficient to function as a dam plate (flat plate) when placing concrete, and the flexible portion is flexible enough to follow and closely contact the uneven surface. It can also be of thickness or shape.

  When the same resin material is used to form the weir plate and the thickness is adjusted to give rigidity or flexibility, the pressing portion is, for example, a plate member having a thickness of 1 mm or more, preferably a plate member having a thickness of 3 mm or more. The dam plate body has a thickness of 2 mm or more, preferably 6 mm or more, and the flexible portion has a thickness of 3 mm or more, preferably 6 mm or more. At this time, it is preferable that the cross section of the flexible portion is tapered. Moreover, when the cross-sectional shape of the flexible portion is not tapered (for example, when the thickness is uniform), the thickness of the dam plate body may be 1.5 times or more the thickness of the flexible portion. desirable.

  Further, when the dam plate is formed using the same metal material (for example, spring steel such as SUP), the thickness of the dam plate body and the flexible portion is, for example, 1 mm or less. When a metal material such as spring steel is used, the flexible portion is, for example, a plate member having a uniform thickness.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the first and second embodiments, the dam plate and the water stop rubber as the water stop device are configured as separate bodies, but the third embodiment is formed by integrally molding them. In addition, about the structure similar to 1st and 2nd embodiment, while using the same referential mark, the description is abbreviate | omitted.

  FIG. 11 is a side view of the weir plate integrated water stop device 60 of the third embodiment. As shown in the figure, flexible portions 61A and 61B are integrated with a U-shaped water stop rubber 61. As shown in FIG. Is provided. Weir plates 62A and 62B made of a hard material are attached to the side wall surfaces at both ends of the U-shaped waterstop rubber 61. That is, the water stop rubber 61, the flexible portions 61A and 61B, and the weir plates 62A and 62B are integrally formed. The water stop rubber 61 and the flexible portions 61A and 61B are made of the same material, for example.

  The flexible portions 61A and 61B extend outward from the lower side portions of the barrier plates 62A and 62B, and the tip portions thereof are formed in a tapered shape. The angle formed by the weir plates 62A and 62B and the flexible portions 61A and 61B is 0 to 90 °, preferably 30 to 60 °, as in the first and second embodiments. In this embodiment, the dam plates 62A and 62B are made of steel and fixed to the anchor bolts 22A and 22B by welding, respectively, but may be fixed by bolts as in the first and second embodiments. In this case, the weir plates 62A and 62B may be hard plates made of rubber or resin.

  Next, FIG. 12 shows a modification of the third embodiment. In the weir plate integrated water stop device 63 in the modified example of FIG. 12, the water stop rubber 64 is molded into an inverted U shape, and the flexible portions 64A and 64B are Extend outward in a letter shape. Adhering portions 65A and 65B for adhering to the barrier plates 62A and 62B are provided on both sides of the inverted U-shaped rubber sheet. Other configurations are the same as those of the third embodiment.

  As described above, according to the third embodiment and the modification thereof, the same effect as that of the first embodiment can be obtained, and the water stop device and the dam plate are integrated, and thus it is necessary to provide a pressing plate. The number of parts can be reduced. Also, the construction efficiency is improved.

  In the present embodiment, the flexible portion is provided on one side of the dam plate, but the flexible portion may be provided on a plurality of sides of the dam plate.

It is a perspective view which shows a part of weir board and water stop apparatus of 1st Embodiment installed between bridge | bridges or between the bridge | bridge and an abutment. It is a side view of the dam plate and water stop apparatus which are shown by FIG. It is a sectional side view which shows the state (state before concrete placement) which installed the weir board and the water stop apparatus shown by FIG. It is a sectional side view when the water stop rubber and dam plate of 1st Embodiment are combined with the steel vertical joint using a corrugated steel plate. It is a sectional side view when the water-stopping rubber and barrier plate of 1st Embodiment are combined with the rubber joint (state after concrete placement). It is a sectional side view which expands and shows the relationship between a weir board and a bridge girder. It is a side view which shows the state in which the weir board of 2nd Embodiment was attached to the anchor bolt with the water stop rubber. It is a sectional side view of the dam plate of 2nd Embodiment. It is a sectional side view of the dam plate of the 1st modification of 2nd Embodiment. It is a sectional side view of the dam plate of the 2nd modification of 2nd Embodiment. It is a side view of the weir board integrated water stop apparatus of 3rd Embodiment. It is a side view of the weir board integrated water stop device of the modification of 3rd Embodiment.

Explanation of symbols

10, 61, 64 Water stop rubber 11A, 11B Weir plate 23A, 23B Holding plate 30 Simple steel joint 40 Steel vertical joint 60, 63 Water stop integrated device 61A, 61B Flexible portion 62A, 62B Weir plate 64A, 64B Flexible portion 70 Rubber joint 80A, 80B Dam plate 110A, 110B Dam plate body 111A, 111B Flexible portion 112A, 112B Holding portion 113A, 113B Curved portion 114A, 114B Curved portion (constricted portion)
115A, 115B curved portion

Claims (14)

  A dam plate used as a formwork for casting concrete, and a dam plate main body that exhibits rigidity as a flat plate during concrete pouring, and is provided on at least one side of the dam plate main body and is flexible enough to follow unevenness A dam plate comprising a portion.   The dam plate according to claim 1, wherein the dam plate body is made of a hard material, and the flexible portion is made of a soft material.   The barrier plate is used as an inner mold for placing concrete in a box opening portion formed on both sides of the play, the flexible portion is pressed against the side wall surface forming the play space, and the side wall surface is uneven. The dam plate according to claim 1, wherein the dam plate closely contacts the side wall surface.   The dam plate according to claim 1, wherein the flexible portion is provided obliquely with respect to the dam plate body.   The dam plate according to claim 3, wherein an angle of the flexible portion with respect to the dam plate body is 30 to 60 °.   The dam plate according to claim 1, wherein a tip of the flexible portion is formed in a tapered shape.   The barrier plate further includes a pressing portion for sandwiching a sheet member for water stoppage between the gap and the barrier plate main body, and a curved portion that connects the pressing portion and the barrier plate main body. The dam plate according to claim 1.   The dam plate according to claim 7, wherein the curved portion is formed of a soft member and can be bent.   The dam plate according to claim 7, wherein the curved portion is formed as a constricted portion and can be bent.   The dam plate according to claim 7, wherein the curved portion is formed of a hard member or a soft member and is molded in a curved shape in advance.   A water stop device attached between the play, comprising a seat portion, a pair of weir plate portions, and a flexible portion, wherein both long side end portions of the sheet portion are connected to each of the weir plate portions, and the sheet portion And the flexible portion is made of a soft material, the dam plate portion is made of a hard material, and the sheet portion, the dam plate portion, and the flexible portion are integrally formed. .   The water stop device according to claim 11, wherein the flexible portion extends obliquely outward from one side of each of the pair of dam plates.   The water stop device according to claim 12, wherein an angle formed by the flexible portion and the dam plate portion is 30 to 60 °.   The water stop device according to claim 11, wherein the sheet portion and the flexible portion are integrally formed from the same material.

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