Pillar-reinforcement technology beneath existing structures: Small-scale model tests

H. J. Seo, Hangseok Choi, K. H. Lee, G. J. Bae, In Mo Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

More than 90% of the nation's flood damage now occurs in the downtown areas of metropolitan cities, where underground space is highly developed. To prevent and/or minimize such damage, we propose the installation of underground rainwater detention caverns, built beneath existing structures. For achieving flood control, multiple caverns would be used, rather than one larger cavern, which could have stability problems. Because of stress concentration in the pillars between two adjacent caverns, pillar stability is considered the Achilles' heel of a multiple-cavern design concept. Therefore, a new pillar-reinforcement technology for improved pillar stability is proposed. In this technology, reinforcing materials, comprising a steel bar and PC strands, are installed with the application of pressurized grouting, thus applying prestress to the PC strands and anchor body. This method has the advantage of utilizing full strength mobilized in situ ground, while minimizing the necessity to construct precast concrete structures. Using pressurized grouting provides an increase in ground strength, and even more importantly, it reduces stress concentrations in the pillars. Applying prestress further increases ground strength because of the increase in internal pressure. In this study, numerical analyses and small-scale model tests were performed to verify the ground reinforcement effects. First, the stress changes in a pillar were determined via the small-scale model tests at each construction stage. In particular, changes in the major and minor principal stresses were measured at the sidewalls, using a p-q diagram, to assess the safety of pillars. The influence of pressurized grouting on the pillar behavior was ascertained. The zone affected by the prestress level was verified by varying the prestress during the smallscale model tests. Further, experimental results were compared with the results of numerical analyses; reasonably good correlation was observed.

Original languageEnglish
Pages (from-to)819-826
Number of pages8
JournalKSCE Journal of Civil Engineering
Volume18
Issue number3
DOIs
Publication statusPublished - 2014 Jan 1

Fingerprint

Grouting
Reinforcement
Stress concentration
Flood damage
Flood control
Precast concrete
Anchors
Concrete construction
Steel

Keywords

  • pillar
  • pressurized grouting
  • prestress
  • underground rainwater detention cavern

ASJC Scopus subject areas

  • Civil and Structural Engineering

Cite this

Pillar-reinforcement technology beneath existing structures : Small-scale model tests. / Seo, H. J.; Choi, Hangseok; Lee, K. H.; Bae, G. J.; Lee, In Mo.

In: KSCE Journal of Civil Engineering, Vol. 18, No. 3, 01.01.2014, p. 819-826.

Research output: Contribution to journalArticle

@article{3387d974a70f4b4cb9dbe09f1ea592b0,
title = "Pillar-reinforcement technology beneath existing structures: Small-scale model tests",
abstract = "More than 90{\%} of the nation's flood damage now occurs in the downtown areas of metropolitan cities, where underground space is highly developed. To prevent and/or minimize such damage, we propose the installation of underground rainwater detention caverns, built beneath existing structures. For achieving flood control, multiple caverns would be used, rather than one larger cavern, which could have stability problems. Because of stress concentration in the pillars between two adjacent caverns, pillar stability is considered the Achilles' heel of a multiple-cavern design concept. Therefore, a new pillar-reinforcement technology for improved pillar stability is proposed. In this technology, reinforcing materials, comprising a steel bar and PC strands, are installed with the application of pressurized grouting, thus applying prestress to the PC strands and anchor body. This method has the advantage of utilizing full strength mobilized in situ ground, while minimizing the necessity to construct precast concrete structures. Using pressurized grouting provides an increase in ground strength, and even more importantly, it reduces stress concentrations in the pillars. Applying prestress further increases ground strength because of the increase in internal pressure. In this study, numerical analyses and small-scale model tests were performed to verify the ground reinforcement effects. First, the stress changes in a pillar were determined via the small-scale model tests at each construction stage. In particular, changes in the major and minor principal stresses were measured at the sidewalls, using a p-q diagram, to assess the safety of pillars. The influence of pressurized grouting on the pillar behavior was ascertained. The zone affected by the prestress level was verified by varying the prestress during the smallscale model tests. Further, experimental results were compared with the results of numerical analyses; reasonably good correlation was observed.",
keywords = "pillar, pressurized grouting, prestress, underground rainwater detention cavern",
author = "Seo, {H. J.} and Hangseok Choi and Lee, {K. H.} and Bae, {G. J.} and Lee, {In Mo}",
year = "2014",
month = "1",
day = "1",
doi = "10.1007/s12205-014-1392-3",
language = "English",
volume = "18",
pages = "819--826",
journal = "KSCE Journal of Civil Engineering",
issn = "1226-7988",
publisher = "Korean Society of Civil Engineers",
number = "3",

}

TY - JOUR

T1 - Pillar-reinforcement technology beneath existing structures

T2 - Small-scale model tests

AU - Seo, H. J.

AU - Choi, Hangseok

AU - Lee, K. H.

AU - Bae, G. J.

AU - Lee, In Mo

PY - 2014/1/1

Y1 - 2014/1/1

N2 - More than 90% of the nation's flood damage now occurs in the downtown areas of metropolitan cities, where underground space is highly developed. To prevent and/or minimize such damage, we propose the installation of underground rainwater detention caverns, built beneath existing structures. For achieving flood control, multiple caverns would be used, rather than one larger cavern, which could have stability problems. Because of stress concentration in the pillars between two adjacent caverns, pillar stability is considered the Achilles' heel of a multiple-cavern design concept. Therefore, a new pillar-reinforcement technology for improved pillar stability is proposed. In this technology, reinforcing materials, comprising a steel bar and PC strands, are installed with the application of pressurized grouting, thus applying prestress to the PC strands and anchor body. This method has the advantage of utilizing full strength mobilized in situ ground, while minimizing the necessity to construct precast concrete structures. Using pressurized grouting provides an increase in ground strength, and even more importantly, it reduces stress concentrations in the pillars. Applying prestress further increases ground strength because of the increase in internal pressure. In this study, numerical analyses and small-scale model tests were performed to verify the ground reinforcement effects. First, the stress changes in a pillar were determined via the small-scale model tests at each construction stage. In particular, changes in the major and minor principal stresses were measured at the sidewalls, using a p-q diagram, to assess the safety of pillars. The influence of pressurized grouting on the pillar behavior was ascertained. The zone affected by the prestress level was verified by varying the prestress during the smallscale model tests. Further, experimental results were compared with the results of numerical analyses; reasonably good correlation was observed.

AB - More than 90% of the nation's flood damage now occurs in the downtown areas of metropolitan cities, where underground space is highly developed. To prevent and/or minimize such damage, we propose the installation of underground rainwater detention caverns, built beneath existing structures. For achieving flood control, multiple caverns would be used, rather than one larger cavern, which could have stability problems. Because of stress concentration in the pillars between two adjacent caverns, pillar stability is considered the Achilles' heel of a multiple-cavern design concept. Therefore, a new pillar-reinforcement technology for improved pillar stability is proposed. In this technology, reinforcing materials, comprising a steel bar and PC strands, are installed with the application of pressurized grouting, thus applying prestress to the PC strands and anchor body. This method has the advantage of utilizing full strength mobilized in situ ground, while minimizing the necessity to construct precast concrete structures. Using pressurized grouting provides an increase in ground strength, and even more importantly, it reduces stress concentrations in the pillars. Applying prestress further increases ground strength because of the increase in internal pressure. In this study, numerical analyses and small-scale model tests were performed to verify the ground reinforcement effects. First, the stress changes in a pillar were determined via the small-scale model tests at each construction stage. In particular, changes in the major and minor principal stresses were measured at the sidewalls, using a p-q diagram, to assess the safety of pillars. The influence of pressurized grouting on the pillar behavior was ascertained. The zone affected by the prestress level was verified by varying the prestress during the smallscale model tests. Further, experimental results were compared with the results of numerical analyses; reasonably good correlation was observed.

KW - pillar

KW - pressurized grouting

KW - prestress

KW - underground rainwater detention cavern

UR - http://www.scopus.com/inward/record.url?scp=84897084045&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84897084045&partnerID=8YFLogxK

U2 - 10.1007/s12205-014-1392-3

DO - 10.1007/s12205-014-1392-3

M3 - Article

AN - SCOPUS:84897084045

VL - 18

SP - 819

EP - 826

JO - KSCE Journal of Civil Engineering

JF - KSCE Journal of Civil Engineering

SN - 1226-7988

IS - 3

ER -