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KR-102961882-B1 - Preloading and maintenance method of reinforcement pile

KR102961882B1KR 102961882 B1KR102961882 B1KR 102961882B1KR-102961882-B1

Abstract

The present invention relates to a method for applying and maintaining a preload on a reinforcing pile, which allows for the early recovery of the loading device to achieve excellent equipment operation efficiency, while also resolving load imbalance between existing piles and newly installed reinforcing piles by monitoring and adjusting the magnitude of the preload on the reinforcing pile. The present invention comprises: (a) a step of forming a bore hole in a foundation plate at a location where a reinforcing pile is to be constructed; (b) a step of constructing a plurality of reaction anchors inside or around the bore hole such that their upper ends protrude above the bore hole, and a step of constructing a reinforcing pile by embedding it into the ground through the bore hole so that its upper end protrudes above the bore hole; (c) a step of placing a loading plate on the upper end of the reinforcing pile so that the reaction anchors penetrate; (d) a step of placing a load cell on the upper end of the loading plate and placing a load plate on the upper end of the load cell so that the reaction anchors penetrate; (e) a step of placing a load-applying device on the upper end of the load plate and placing a reaction plate on the upper end of the load-applying device so that the reaction anchors penetrate, thereby fixing the reaction plate to the reaction anchors; and (f) a step of applying a preload to the reinforcing pile by operating the load-applying device to press the load plate, load cell, and loading plate.

Inventors

  • 하효진
  • 김영석
  • 정용섭
  • 박정규
  • 권혁범
  • 조인성
  • 강민수

Assignees

  • (주)포스코이앤씨
  • 케이에이치건설 주식회사

Dates

Publication Date
20260508
Application Date
20240603

Claims (8)

  1. A reinforcing pile (3) is driven into the ground (1) through a drilled hole (21) formed in the base plate (2) of an existing structure and a preload is introduced, and the introduced preload is maintained. (a) A step of forming a hole (21) in the base plate (2) at the location where the reinforcing pile (3) is to be constructed; (b) A step of installing a plurality of reaction anchors (4) such that their upper ends protrude above the hole (21) inside or around the hole (21), and installing a reinforcing pile (3) into the ground (1) through the hole (21) so that its upper end protrudes above the hole (21); (c) A step of mounting a loading plate (5a) on the top of the reinforcing pile (3) so that the reaction anchor (4) penetrates; (d) a step of mounting a load cell (6a) on the upper part of the loading plate (5a), mounting a load plate (5b) on the upper part of the load cell (6a) so that the reaction anchor (4) passes through, and then fastening a load plate fixing nut (51b) to the reaction anchor (4) on the upper part of the load plate (5b); (e) A step of mounting a force device (7) on the upper part of the force plate (5b), and mounting a reaction plate (5c) on the upper part of the force device (7) so that the reaction anchor (4) passes through, thereby fixing the reaction plate (5c) to the reaction anchor (4); (f) a step of applying a pre-load to the reinforcing pile (3) by operating the above-mentioned force device (7) to press the above-mentioned force plate (5b), load cell (6a) and loading plate (5a); (g) A step of lowering the above-mentioned force plate fixing nut (51b) to fix the force plate (5b); (h) Step of removing the above-mentioned force device (7); (i) a step of monitoring the preload of the reinforcing pile (3) measured by the load cell (6a); and (j) a step of reinstalling a loading device (7) between the loading plate (5b) and the reaction plate (5c) and operating the loading device (7) according to the measured loading device to apply an additional load to the loading pile (3); characterized by comprising a method for loading a loading device and maintaining a loading device on a loading pile.
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  4. In Paragraph 1, Step (c) above involves installing the loading plate (5a) and then fastening the loading plate fixing nut (51a) to the reaction anchor (4) on the upper part of the loading plate (5a). After the above (j) step, (k) lowering the loading plate fixing nut (51a) to fix the loading plate (5a), and removing the reaction plate (5c), the applying plate (5b), and the load cell (6a); and (l) a step of removing the upper protrusion of the base plate (2) of the reaction anchor (4) and pouring non-shrink mortar (M) into the space between the drilled hole (21) and the reinforcing pile (3) to anchor the head of the reinforcing pile (3) inside the base plate (2); further comprising a reinforcing pile preloading and maintenance method.
  5. In Paragraph 4, The above reaction anchor (4) is fixed to the base plate (2) and consists of a lower anchor (4a) whose upper end does not protrude above the base plate (2) and an upper anchor (4b) which is connected to the upper end of the lower anchor (4a). In step (b) above, a lower anchor (4a) is installed, and In step (c) above, the loading plate fixing nut (51a) is fastened to the lower anchor (4a), and then the upper anchor (4b) is connected to the upper part of the lower anchor (4a) using a coupler (40). The above step (l) is characterized by removing the upper anchor (4b) by dismantling the coupler (40), and is a method for applying a preload to a reinforcing pile and maintaining it.
  6. In Paragraph 1, Step (b) above involves installing a reaction anchor (4) on the inner outer side of the drilled hole (21), and A method for applying a pre-load to a reinforcing pile and maintaining it, characterized in that a casing member (8) including a cylindrical casing body (81) is inserted into the inner side of the reaction anchor (4), and non-shrink mortar (M) is poured between the inner wall of the drilled hole (21) and the casing body (81), thereby anchoring the reaction anchor (4) to the base plate (2).
  7. In paragraph 6, A method for applying a pre-load to a reinforcing pile and maintaining it, characterized in that the upper part of the casing body (81) of the above-mentioned casing member (8) is further provided with a flange (82) through which the reaction anchor (4) passes, which is positioned over the upper part of the drilled hole (21).
  8. In Paragraph 1, A control server (9) is provided to receive pre-load data measured by the load cell (6a) and to transmit a control signal to the load applying device (7). A method for applying and maintaining a reinforcing pile preload, characterized in that the control server (9) controls the loading device (7) in step (f) to apply a preload with a management load ( P1 ) that is larger than the target load ( P0 ), and in step (j), if the preload measured by the load cell ( 6a ) decreases to the target load (P0), the control server (9) controls the loading device (7) to increase the preload to the management load ( P1 ).

Description

Preloading and maintenance method of reinforcement pile The present invention relates to a method for applying and maintaining a preload on a reinforcing pile embedded in the ground by penetrating the foundation plate of an existing structure, which offers excellent equipment operation efficiency by allowing the loading device to be retrieved early, and resolves load imbalance between the existing pile and the newly installed reinforcing pile by monitoring and adjusting the magnitude of the preload on the reinforcing pile. Reconstruction, which involves the complete demolition of aging multi-unit housing and the construction of new buildings, faces difficulties in project implementation due to safety inspection requirements and various regulations. In contrast, remodeling is subject to relatively fewer regulations and proceeds faster, making it a common method for revitalizing aging buildings recently. In remodeling projects, vertical expansion offers excellent business feasibility as it allows for an increase in gross floor area without adding to the building area. However, vertical expansion increases the load burden on existing piles due to the additional vertical load caused by the upper extension structure. Therefore, additional reinforcing piles must be installed to support this increased load. If reinforcement piles are simply added to the existing foundation, the existing piles, which are already supporting the vertical load of the existing building, will bear the additional vertical load resulting from the extension. On the other hand, the newly installed reinforcement piles will bear only the additional load caused by the extension without bearing the vertical load of the existing structure. Consequently, a load imbalance occurs between the existing piles and the newly installed reinforcement piles. If piles are designed without considering such uneven loading and behavior, there is a problem where differential settlement occurs or additional moments are generated in the foundation, increasing the stress burden on the foundation. To solve these problems, Registered Patent No. 10-1494260 and Published Patent No. 10-2018-0112907, etc., aim to resolve the load imbalance between the existing pile and the reinforcing pile by installing a preload jack on top of the additionally installed reinforcing pile and anchoring the reinforcing pile to the foundation while applying a load to the newly installed reinforcing pile by the load of the preload jack. In this conventional preloading method, a preload is applied to the reinforcement pile using a hydraulic jack, and then the pile is anchored by filling the borehole where the pile is to be installed with non-shrink mortar. Consequently, the hydraulic jack can only be removed after the non-shrink mortar has hardened, making equipment operation inefficient and increasing the cost burden when installing reinforcement piles at multiple locations. In addition, during the construction process of individual reinforcing piles, changes in stress acting on the foundation plate are inevitable due to the construction of surrounding reinforcing piles, and the load acting on the reinforcing piles is bound to change depending on the construction stage of the superstructure, but conventional preloading methods cannot monitor these stress changes or readjust the preload after monitoring. Furthermore, individually pre-constructed pre-reinforcement piles act as reaction piles when pre-loading is applied to subsequently constructed reinforcement piles, thereby reducing stress transfer to the existing piles and diminishing the effectiveness of the pre-reinforcement method. Consequently, it is practically difficult to determine whether the load on the existing piles is reduced, and load imbalance may be exacerbated depending on the arrangement of the existing piles and reinforcement piles, or the order of pile reinforcement. FIGS. 1 to 7 are drawings illustrating the step-by-step process for the preloading and maintenance of reinforcing piles according to the present invention. FIG. 8 is a drawing illustrating step (g). FIG. 9 is a drawing illustrating step (h). FIG. 10 is a cross-sectional perspective view illustrating the state in which a displacement gauge is installed. FIG. 11 is a cross-sectional perspective view illustrating the lowering of the loading plate fixing nut in step (k). FIG. 12 is a cross-sectional perspective view illustrating the removal state of the upper protrusion in step (l). FIG. 13 is a cross-sectional perspective view illustrating the pouring state of non-shrink mortar in step (l). FIG. 14 is a perspective view illustrating a casing member. FIG. 15 is a perspective view illustrating the combined state of a casing member and a reaction anchor. FIG. 16 is a cross-sectional perspective view illustrating a state in which non-shrink mortar is poured into the inside of a bore hole by a casing member. FIG. 17 is a drawing illustrating an automatic management s