The present invention relates to a placement method of reinforcing strips for constructing a precast concrete facing panel and a pulling-up device of reinforcing strips, and more particularly, to a placement method and device which can prevent deformation of a concrete facing panel (also referred to as a concrete retaining wall) from occurring after completing the placement by pulling-up synthetic resin reinforcing strips having strip fabrics incorporated in tiers at regular spacing with a constant tension so as not to be loosened, and which can greatly reduce labor force and time required for placing the same.
In general, a method of placing reinforcing strips for constructing a precast concrete facing panel using reinforcing strips made of construction fabrics (called a “WEBSOL” technique) is performed by steps of placing and curing base concrete at level on the ground where a facing panel is to be installed to a depth of 20 cm and a width of 40 to 50 cm, installing a prop before mounting reinforcing strips made of fabrics for the purpose of preventing deformation which may arise when a concrete facing panel (retaining wall) is mounted on the base concrete and backfill soil is hardened, installing a clamp between panels for the purpose of preventing deformation which may arise when a concrete facing panel (retaining wall) is mounted on the base concrete and backfill soil is hardened and then inserting a vertical batten filler made of construction fabrics for use in highly water-permeable filter for drainage from the backfill soil, installing a key-wood on a joint of the front face of the concrete facing panel to a predetermined height until the processes of forming retaining soil to a predetermined height and hardening the same are completed, for the purposes of maintaining linearity of the installed concrete facing panel and preventing deformation thereof, connecting the reinforcing fabrics to a fixed reinforcing iron bar provided at the rear portion fixed by a fixing hook buried into the internal side of the facing panel and an anchor in a zigzag pattern and pulling up the same manually, laying a backfill material on the reinforcing strip and applying vibration and pressure to the resultant structure to have a predetermined thickness using a heavy equipment for hardening the resultant structure, and repeating the hardening step until approximately 2 m upward from the facing panel is reached using a small-sized hardening equipment while piling up the facing panel.
The conventional method of constructing a precast concrete facing panel poses various problems and difficulties in terms of working efficiency. That is to say, at least 4 to 5 worker must be involved in interconnecting the reinforcing strips between the interior surface of the facing panel and the fixed reinforcing iron bar in a zigzag pattern. In detail, manually pulling-up the reinforcing strips requires 2 or 3 workers, pressing the reinforcing strips at a bent portion at the fixing hook of the facing panel side requires at least one worker, and inducing the reinforcing strips reversed at the fixing iron bar and pulling up the same requires at least one worker. However, in the case where the length of each of the reinforcing strips to be constructed is increased as per specification, at least 7 to 8 workers are required. In particular, the worker in charge of the pulling-up work experiences physical fatigue and lowered working efficiency because the reinforcing strip is too wide and high for the worker to be pulled up by hand, e.g. as wide as approximately 10 cm. Also, it is quite difficult to pull up the reinforcing strips with a constant tension, resulting in a deformed facing panel, that is, a potbellied or twisted facing panel, after completing the placement, due to the loosened reinforcing strips remaining on the reinforcing soil member.
Several attempts to prevent the reinforcing strips from being loosened have been made, including a method of laying a reinforcing soil member using a heavy equipment in a state in which the reinforcing strips are forcibly pulled up such that a worker locks a lever in front of a fixing iron bar to be pushed away rearward, and a method of partially digging reinforcing strips and laying a reinforcing soil member thereon so that the reinforcing strips are pulled up while the dig portion of the reinforcing strips is buried. However, these methods are not so effective in preventing the reinforcing strips from being loosened and for applying an appropriate tension to the reinforcing strips. That is, since a most severely loosened portion of the reinforcing strips connected between the concrete facing panel and the fixing iron bar correspond to bent portions of the fixing hook at the interior surface of the concrete and the fixing iron bar at the rear end of the reinforcing soil member, the loosening of these portions cannot be effectively eased by the above-reference methods.
The present invention is proposed to overcome the disadvantages discussed above relating to conventional placement method of reinforcing strips for constructing a precast concrete facing panel, that is, construction difficulties and deformation arising after completing the placement. Therefore, it is an object of the present invention to provide a method of placing reinforcing strips, by which a pulling-up work of the reinforcing strips can be performed with an appropriate tension to prevent deformation of the reinforcing strips from occurring after completing the placement and to prevent the loosening of a concrete facing panel, and which can be performed faster, more easily and accurately.
It is another object of the present invention to provide a pulling-up device of a reinforcing strips, which is suitable for the above-described placement method and which can pull up the reinforcing strips more easily and faster.
To accomplish the first object of the present invention, there is provided a reinforcing strip placement method in a method of supporting a facing panel by zigzag-connecting synthetic resin reinforcing strips between fixing hookers formed on the interior surface of a concrete facing panel and a fixing iron bar fixed at the rear of a reinforcing soil member by means of an anchor, and burying the reinforcing strips into the reinforcing soil member at the rear of the concrete facing panel, the reinforcing strip placement method wherein a pulling-up device is locked between a rear end of the reinforcing strips and the fixing iron bar fixed by means of the anchor and pulled sequentially from one end to the other end of each of the reinforcing strips zigzag-connected between the concrete facing panel and the fixing iron bar, thereby preventing loosening of the reinforcing strips and applying a constant tension thereto, and then the reinforcing soil member is laid on the resultant structure and hardened by applying vibration and pressure thereto.
In an embodiment of the present invention, there is provided reinforcing strip pulling-up device having a gripper for gripping a reinforcing strip, a wire grip for pulling up the reinforcing strip gripped by the gripper, and a fixing hook connected to a rear end of the wire grip to be hooked to a temporarily fixing iron bar on the ground or at the rear end of a reinforcing soil member, wherein the gripper comprises a base on which the reinforcing strip is placed, a lateral plate extending upward at one side of the base, a support shaft fixed to the lateral plate to be parallel to the base, an eccentric roller allowing the reinforcing strip to be placed on the base to be inserted thereinto and gripped while being eccentrically fitted into the support shaft and rotating, and a connecting plate formed at one side of the lateral plate and having a rear end fixed to the leading edge of a tensiometer connected to the wire grip.
In the present invention, connection holes for selective installation of the connecting plate are preferably formed at the front and rear sides of the lateral plate.
Also, at least two of the base, the lateral plate and the connecting plate are preferably integrally formed with each other. Alternatively, while the base and the lateral plate are integrally fabricated, only the connecting plate may be separately fabricated and assembled by means of a bolt. Otherwise, while only the base is separately fabricated, the lateral plate and the connecting plate may be integrally fabricated, and the base, the lateral plate and the connecting plate can be assembled to one another by means of bolts.
Further, since the lower portions of the front and rear surfaces of the base and the lateral plane move back and forth in a state in which they are in contact with the ground of the reinforcing soil member, chamfer planes for reducing resistance against the ground and avoiding user's damage may be formed at the lower portions of the front and rear sides of the base. The surface of the eccentric roller is embossed to increase the friction between the surface of the eccentric roller and the surface of the reinforcing strip.
In another embodiment of the present invention, there is provided a reinforcing strip pulling-up device having a gripper for gripping a reinforcing strip, a wire grip for pulling up the reinforcing strip gripped by the gripper, and a fixing hook connected to a rear end of the wire grip to be hooked to a temporarily fixing iron bar on the ground or at the rear end of a reinforcing soil member, the improvement comprising a tensiometer configured such that the strength of tension applied to a reinforcing strip is confirmed by naked eye, the tension applied when the reinforcing strip is pulled by manipulating the wire grip in a state in which the reinforcing strip is gripped by the gripper such that the tensiometer is connected between the fixing hook and the wire grip, and an auxiliary lever bent or unbent at right angle at a lever for manipulating the wire grip, for pulling a wire of the wire grip by rotating the lever in a state in which the lever is laid down or by repeatedly moving the lever back and forth.
In a still another embodiment of the present invention, there is provided reinforcing strip pulling-up device having a gripper for gripping a reinforcing strip, a wire grip for pulling up the reinforcing strip gripped by the gripper, and a fixing hook connected to a rear end of the wire grip to be hooked to a temporarily fixing iron bar on the ground or at the rear end of a reinforcing soil member, wherein the wire grip includes a pair of levers at the right and left sides thereof so as to pull up a wire of the wire grip while manipulating the levers by both hands back and forth.
As shown in
In the reinforcing strip placement method according to the present invention, a worker can pull up the reinforcing strips using a single pulling-up device sequentially from a rear end of each of the reinforcing strips. Preferably, as shown in
According to the reinforcing strip placement method of the present invention, when the pulling-up work for the second line is completed, the pulling-up device 10 for the first line is removed and then shifted to the third line to be locked while the pulling-up device 10′ for the second line is retained at a locked state. This work is continuously repeated, thereby completing a sequence of installation and pulling-up works of the reinforcing strips.
In this embodiment, the gripper 100 is constructed such that the base 110, the lateral plate 120 and the connecting plate 160 are separately fabricated and then integrally connected to one another by means of bolts 170 and 172. Otherwise, the base 110, the lateral plate 120 and the connecting plate 160 may be integrally fabricated. Alternatively, while the base 110 and the lateral plate 120 are integrally fabricated, only the connecting plate 160 may be separately fabricated and assembled by means of a bolt. Otherwise, while only the base 110 is separately fabricated, the lateral plate 120 and the connecting plate 160 may be integrally fabricated, and the base 110, the lateral plate 120 and the connecting plate 160 can be assembled to one another.
A top plane 112 of the base 110 is planar so that the reinforcing strip placed thereon becomes slidable, and chamfer planes 114 and 116 for reducing resistance against the ground are formed at the lower portions of the front and rear sides of the base 110. A female screw hole (not shown) for bolt connection with the lateral plate 120 is formed at the lateral surface of the base 110.
Connection holes 122 for bolt connection with the base 110 are formed through at the lower portion of the lateral plate 120. A shaft fixing hole 126 into which one end of the support shaft 130 is inserted, to be fixed by a set screw 124, is formed at the upper portion of the lateral plate 120. Connection holes 128 for selective installation of the connecting plate 160 are formed at the front and rear sides of the lateral plate 120. In such a manner, the connecting plate 160 can be fixed on the front or rear surface of the lateral plate 120 such that the reinforcing strip can be pushed away left or right according to user's preference or conditions of a construction site where the pulling-up device is to be used.
The eccentric roller 140 inserted into the support shaft 130 is formed with eccentricity, that is, in such a manner that the center of an internal shaft hole 142 deviates from the center of the outer diameter of the eccentric roller 140. Thus, if the eccentric roller 140 rotates in a state in which it is inserted into the support shaft 130, the gap between the eccentric roller 140 and the top plane 112 of the base 110 becomes narrower or wider. That is, as shown in
In order to increase the friction between the surface of the eccentric roller 140 and the surface of the reinforcing strip 400, the surface of the eccentric roller 140 is embossed.
Referring back to
The tensiometer 150 is configured such that the strength of tension applied to the reinforcing strip can be confirmed by naked eye, the tension applied when the reinforcing strip is pulled by manipulating the wire grip 200 in a state in which the reinforcing strip is gripped by the gripper 100 such that a male screw 152 of its front end is connected to a female screw hole 162 of the connecting plate 160 and a male screw 154 of its rear end is connected to the wire grip 200, and includes a compression spring.
Holes 125 and 127 for selectively installing a stopper 180 are formed at the front and rear of the upper portion of the lateral plate 120. The stopper 180 for preventing the eccentric roller 140 from excessively rotating, is in contact with a outer portions of the eccentric roller 140 and controls unidirectional rotation of the eccentric roller 140, as shown in FIG. 4.
In the present invention, the gripper 100 for gripping the reinforcing strip 400 consists of the base 110 provided at the lower portion thereof and the eccentric roller 140 provided at the upper portion thereof, and the reinforcing strip 400 is horizontally gripped therebetween. Thus, there is no warp of the reinforcing strip at a gripped portion by gripping and pulling-up the reinforcing strip in a state in which the reinforcing strip is spread over the reinforcing soil member. If the pulling-up work is completed, the reinforcing strip is not loosened, thereby achieving more accurate placement. Also, the reinforcing strip 400 can be inserted between the base 110 and the eccentric roller 140 just by advancing the gripper 100 therebetween, and the reinforcing strip 400 can be gripped just by retracting the gripper 100. Thus, it is not necessary to apply press or remove pressure using a pressing handle, unlike in the prior art, or to manipulate a gap adjusting device for adjusting an appropriate gap, thereby performing the gripping work more easily and fast. Also, the gripper 100 can be miniaturized, and can be simplified, thereby attaining better manageability thereof.
The above-described construction according to the present invention is used in such manners as shown in
In the above-described manipulating process, the tension applied to the wire is not so strong. Thus, the lever L rotates easily. If a greater force is applied as the number of rotations of the lever L increases, the reinforcing strip can be tightly pulled as the wire is pulled by manipulating the lever L back and forth, in a state in which the wire grip 200 is allowed to stand so as to make the lever L stand accordingly and the auxiliary lever L1 is aligned with the lever L, as shown in FIG. 11. Then, after adjusting an appropriate tension while observing graduations of the tensiometer 450, the reinforcing strip fixing work is performed.
In this embodiment, since the tensiometer 450 is integrally formed with the fixing hook 300 and is positioned at the rear of the wire grip 200, the tension applied to the reinforcing strip can be easily observed by worker's naked eye just by looking down while the worker manipulates the lever L.
In other words, the pulling-up device according to this embodiment includes the levers 15a and 15b provided at both sides of the wire grip 14 to be alternately driven, thereby pulling up the wire two times faster than the conventional wire grip in which only a lever is provided and only one hand is used in manipulating the wire grip.
As shown in
According to the present invention, in the process of pulling up a reinforcing strip, the pulling-up work can be done by a single worker using the present invention pulling-up device. Also, since the pulling-up device is manipulated in a state in which it is locked between the rear end of the reinforcing strip and a fixing iron bar, construction of the reinforcing strip can be completed even at a construction site where obstacles such as rock or other pre-installed construction exist at the rear of a reinforcing soil member, without any difficulty.
Further, since a pair of levers are provided at the pulling-up device according to the present invention, a worker can manipulate the levers by both hands, thereby completing the pulling-up work more rapidly. Also, since the pulled state of the reinforcing strip is adjusted constantly while observing a tensiometer, deformation of a concrete facing panel, which may occur due to a nonuniform pulling-up work of the reinforcing strip after hardening a reinforcing soil member, can be prevented.
In contrast with the conventional technology in which a worker must pull up a reinforcing strip with the reinforcing strip gripped with a hand, according to the present invention, a worker has only to pull up the lever of a wire grip with a reinforcing strip gripped by a gripper, thereby reducing the worker's physical fatigue and greatly reducing a construction period and labor force.
As described above, according to the present invention, unlike in the prior art in which the construction work is only affected by labor force, a pulling-up device is employed for constructing a precast concrete facing panel, thereby performing a pulling-up work rapidly with a constant tension, leading to accurate construction. Also, a reduction in labor force and a shortened construction period can be achieved. That is, a concrete facing panel can be more effectively constructed, compared to the conventional concrete facing panel.
According to the present invention, when a reinforcing strip is installed at the rear of a concrete facing panel in a zigzag pattern, a pulling-up work can be performed faster, more easily and more accurately with a constant tension, without loosening of a reinforcing strip, thereby improving the working efficiency and accuracy in constructing a precast concrete facing panel. Also, since initial elongation of a reinforcing strip can be controlled initially by a mechanical force of a pulling-up device, initial deformation of the reinforcing strip itself and deformation of the concrete facing panel, which may occur after completing the placement due to a nonuniform pulling-up work of the reinforcing strip, can be prevented.
Number | Date | Country | Kind |
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2000-31205 U | Nov 2000 | KR | national |
2000-34463 U | Dec 2000 | KR | national |
2001-22866 | Apr 2001 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCTKR01/01632 | 9/28/2001 | WO | 00 | 5/7/2003 |
Publishing Document | Publishing Date | Country | Kind |
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WO0238872 | 5/16/2002 | WO | A |
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Number | Date | Country |
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7-90863 | Apr 1995 | JP |
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2000-12630 | Mar 2000 | KR |
Number | Date | Country | |
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20040025315 A1 | Feb 2004 | US |