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KR-102961883-B1 - Preloading and maintenance method of reinforcement pile for remodeling

KR102961883B1KR 102961883 B1KR102961883 B1KR 102961883B1KR-102961883-B1

Abstract

The present invention relates to a method for applying and maintaining a preload on reinforcing piles for remodeling construction, wherein a load measuring means and a loading means are sequentially provided on the upper part of a reinforcing pile embedded in a loading frame anchored within a bore hole of a foundation plate to maintain a preload introduced into the reinforcing pile for foundation reinforcement of an existing structure, thereby enabling long-term monitoring of the effect of introducing the preload by actually measuring the preload, satisfying the design preload level by applying additional load to the reinforcing pile when necessary, and allowing for the early retrieval of the loading means. The present invention relates to a method for introducing a preload to a reinforcing pile additionally constructed in the ground to reinforce the foundation of an existing structure during remodeling work, and for maintaining the introduced preload, comprising: (a) a step of installing a load-applying frame in a bore hole formed in a foundation plate and anchoring it to the foundation plate, while embedding the reinforcing pile into the ground through the bore hole; (b) a step of installing a load measuring means and a load-applying means on the load-applying frame so as to be provided on the upper part of the reinforcing pile; (c) a step of applying a preload to the reinforcing pile by applying a load from the load-applying means; (d) a step of monitoring the load applied to the reinforcing pile by the load measuring means; and (e) a step of operating the load-applying means according to the preload measured by the load measuring means to apply an additional load to the reinforcing pile.

Inventors

  • 하효진
  • 김영석
  • 권혁범
  • 조인성
  • 강민수
  • 이준태
  • 이정은

Assignees

  • (주)포스코이앤씨
  • 케이에이치건설 주식회사

Dates

Publication Date
20260507
Application Date
20250512

Claims (9)

  1. In order to reinforce the foundation of an existing structure during remodeling work, a load-applying frame (4) is configured to include a reaction anchor (41) fixed in a hole (21) formed in a foundation plate (2), a loading plate (42) mounted on the upper end of a reinforcing pile (3) through which the reaction anchor (41) passes, a movable plate (43) that is spaced above the loading plate (42) through which the reaction anchor (41) passes and accommodates a load measuring means (5) between the loading plate (42) and the movable plate (43), and a reaction plate (44) that is spaced above the movable plate (43) through which the reaction anchor (41) passes and accommodates a load-applying means (6) between the movable plate (43) and the movable plate (43). This is for introducing a preload to a reinforcing pile (3) that is additionally constructed on the ground (1) and for maintaining the introduced preload. (a) A step of installing the load-bearing frame (4) in the above-mentioned drilling hole (21) and fixing it to the base plate (2), while inserting a reinforcing pile (3) into the ground (1) through the above-mentioned drilling hole (21); (b) A step of installing the load measuring means (5) and the force applying means (6) on the force applying frame (4) so as to be provided on the upper part of the reinforcing pile (3); (c) A step of fixing the movable plate (43) by fastening the fixing nut (N) to the reaction anchor (41) at the upper part of the movable plate (43), and applying pressure to the load measuring means (5) with the force applying means (6) so that the load measuring means (5) applies pressure to the upper part of the reinforcing pile (3), thereby measuring the magnitude of the preload transmitted between the reinforcing pile (3) and the force applying means (6), and then lowering the fixing nut (N) to fix the movable plate (43); (d) a step of measuring the load applied to the reinforcing pile (3) in real time by the load measuring means (5) above and monitoring the change over time after the introduction of the pre-load; and (e) a step of applying an additional load to the reinforcing pile (3) by operating the loading means (6) according to the preceding load measured by the load measuring means (5); comprising, The above step (c) is, (c 1 ) A step of pre-loading the reinforcing pile (3) with a first load greater than the target load and then removing the load; and (c 2 ) A step of applying a pre-load to the reinforcing pile (3) by applying a second load greater than the target load after a certain period of time; characterized by a method for applying a pre-load to a reinforcing pile and maintaining it for remodeling work.
  2. delete
  3. In paragraph 1, A method for pre-loading and maintaining reinforcing piles for remodeling construction, characterized in that a plurality of reinforcing piles (3) constructed at a target site are divided into at least two zones, and in step (c), the loading means (6) of each zone is controlled to be loaded simultaneously, thereby loading sequentially from the outer zone to the inner zone.
  4. In Paragraph 3, A method for applying a pre-load to reinforcing piles and maintaining them for remodeling construction, characterized in that, in step (c) above, a plurality of zones are sequentially loaded first with a portion of the second load, and then a plurality of zones are sequentially loaded second to reach the second load.
  5. In paragraph 1, A control server (7) is provided to receive pre-load data measured by the load measuring means (5) and to transmit a control signal to the load applying means (6). A method for applying and maintaining a reinforcing pile preload for remodeling construction, characterized in that, after step (d), the control server (7) controls the loading means (6) to increase the preload to a management load ( P1 ) greater than the target load when the preload measured by the load measuring means (5) reaches the target load.
  6. delete
  7. In paragraph 1, Step (a) above involves installing a reaction anchor (41) 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 for remodeling construction, characterized in that a casing (46) is inserted into the inner side of the reaction anchor (41) and non-shrink mortar (M) is poured between the inner wall of the drilled hole (21) of the foundation plate (2) and the casing (46), thereby fixing the reaction anchor (41) to the foundation plate (2).
  8. delete
  9. In paragraph 1, A method for pre-loading and maintaining reinforcing piles for remodeling construction, characterized by having an extension pressure member (30) provided between the reinforcing pile (3) and the loading plate (42).

Description

Preloading and maintenance method of reinforcement pile for remodeling The present invention relates to a method for applying and maintaining a preload on reinforcing piles for remodeling construction, wherein a load measuring means and a loading means are sequentially provided on the upper part of a reinforcing pile embedded in a loading frame anchored within a bore hole of a foundation plate to maintain a preload introduced into the reinforcing pile for foundation reinforcement of an existing structure, thereby enabling long-term monitoring of the effect of introducing the preload by actually measuring the preload, satisfying the design preload level by applying additional load to the reinforcing pile when necessary, and allowing for the early retrieval of the loading means. Reconstruction, which involves the complete demolition of aging multi-unit housing and the construction of new buildings, faces difficulties in implementation due to safety inspection requirements and various regulations. In contrast, remodeling, which utilizes existing structures, is subject to relatively fewer regulations and proceeds faster, making it a common method recently to revitalize aging buildings. 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 constructed pre-reinforcement piles act as reaction piles when preloading 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 difficult to practically determine whether the load on the existing piles has been reduced, and load imbalance may be exacerbated depending on the arrangement of the existing and reinforcement piles or the order of pile reinforcement. FIGS. 1 to 5 are drawings illustrating step (a) of the present invention. FIGS. 6 to 11 are drawings illustrating step (b) of the present invention. FIG. 12 is a cross-sectional view illustrating the state after the execution of steps (a) and (b) of the present invention. Figure 13 is a graph showing the results of preload measurements over time after preloading of the reinforcing pile. Figure 14 is a graph showing the results of measuring the preload during the main loading after the preloading of the reinforcing pile. FIG. 15 is a diagram showing the concept of sequential loading of reinforcing piles by zone using a loading means. FIG. 16 is a drawing illustrating the concept of central monitoring of a pre-load by a load measuring means. FIG. 17 is a diagram illustrating the concept