• Advances in concrete construction
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• 제13권3호
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• pp.243-254
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• 2022

Reinforced concrete (RC) deep beams are critical structural elements used in offshore pile caps, rectangular cross-section water tanks, silo structures, transfer beams in high-rise buildings, and bent caps. As a result of the low shear span ratio to effective depth (a/d) in deep beams, arch action occurs, which leads to shear failure. Several studies have been carried out to improve the shear resistance of RC deep beams and avoid brittle fracture behavior in recent years. This study was performed to investigate the behavior of RC deep beams numerically and experimentally with different reinforcement arrangements. Deep beams with four different reinforcement arrangements were produced and tested under monotonic static loading in the study's scope. The horizontal and vertical shear reinforcement members were changed in the test specimens to obtain the effects of different reinforcement arrangements. However, the rebars used for tension and the vertical shear reinforcement ratio were constant. In addition, the behavior of each deep beam was obtained numerically with commercial finite element analysis (FEA) software ABAQUS, and the findings were compared with the experimental results. The results showed that the reinforcements placed diagonally significantly increased the load-carrying and energy absorption capacities of RC deep beams. Moreover, an apparent plastic plateau was seen in the load-displacement curves of these test specimens in question (DE-2 and DE-3). This finding also indicated that diagonally located reinforcements improve displacement ductility. Also, the numerical results showed that the FEM method could be used to accurately predict RC deep beams'behavior with different reinforcement arrangements.

• 한국지반신소재학회논문집
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• 제7권3호
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• pp.25-30
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• 2008

본 논문에서는 순환골재 다공질 콘크리트말뚝(RAPP)공법에 대한 실내모형실험의 결과를 바탕으로 RAPP로 개량된 복합지반의 침하 및 압밀 거동 특성을 분석하였다. 이를 위하여 실내모형실험에서 관측된 복합지반의 침하량과 무보강 지반의 침하량을 비교하여 복합지반의 침하저감효과를 분석하였으며 복합지반의 압밀도를 산정하여 RAPP공법으로 인한 압밀촉진효과를 검토 하였다. RAPP공법으로 인한 복합지반의 침하저감효과는 상재하중증분이 증가할수록 감소하였으나 전반적으로 SCP공법에 의한 효과보다 크게 나타났으며 압밀촉진효과는 SCP공법과 유사하게 나타났다.

• Earthquakes and Structures
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• 제1권1호
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• pp.129-146
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• 2010

This paper proposes an approximate procedure to estimate seismic displacement capacity - defined as yield displacement times the displacement ductility - of piles in marine oil terminals. It is shown that the displacement ductility of piles is relatively insensitive to most of the pile parameters within ranges typically applicable to most piles in marine oil terminals. Based on parametric studies, lower bound values of the displacement ductility of two types of piles commonly used in marine oil terminals - reinforced-concrete and hollow-steel - with either pin connection or full-moment-connection to the deck for two seismic design levels - Level 1 or Level 2 - and for two locations of the hinging in the pile - near the deck or below the ground - are proposed. The lower bound values of the displacement ductility are determined such that the material strain limits specified in the Marine Oil Terminal Engineering and Maintenance Standard (MOTEMS) are satisfied at each design level. The simplified procedure presented in this paper is intended to be used for preliminary design of piles or as a check on the results from the detailed nonlinear static pushover analysis procedure, with material strain control, specified in the MOTEMS.

• Geomechanics and Engineering
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• 제25권3호
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• pp.171-178
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• 2021

Wave interaction in marine structures is an important issue where requires to be considered in view of number of bases, piles and arrangement method. In this research, effect of waves and their forces on piles with different arrangements was investigated using numerical modeling. Simulations were performed in presence of bracing elements between piles against the force of waves and also were compared with simple arrangement without bracing elements in different arrangements. Results showed that in models that were fitted with bracing elements, the displacement rate reduced about 96%, and tension tolerances increased more than 53% and abutment responses also decreased about 70%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.379-384
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• 2001

This paper presents the experimental result of composite basement wall in which H-pile and reinforced concrete wall are combined using shear connector. Twelve specimens are tested to evaluate the shear capacity of the wall. Main variables in the test are composite ratio, arrangement of shear connector, thickness of wall, shear span ratio, and shear reinforcement. Test results indicate that the shear capacity of test specimens varies with the foregoing variables except the composite ratio. The results are compared with strengths predicted using the equations of ACI 318-99, Zsutty, and Bazant. Based on this investigation, a method for predicting the shear strength of composite basement walls is proposed.

• Journal of Advanced Marine Engineering and Technology
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• 제38권10호
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• pp.1206-1211
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• 2014

This study has been conducted to confirm the effect of sacrificial anode cathodic protection system for 90 days to protect corrosion on pier that is located in Korea. The cathodically protected structure was a slab and a pile cap. Before the construction of cathodic protection system, the macrography was carried out. As a result of the macrography, many corrosion traces were confirmed in this structure. The trace was mainly focused on joint and zones that concrete cover was eliminated. To apply the cathodic protection system, many onsite techniques have been adopted. In addition, to confirm the inner state of steel in concrete properly, a corrosion monitoring sensor (DMS-100, Conclinic Co. Ltd) has been applied. Test factors were corrosion & cathodic protection potential, 4 hour depolarization potential, resistivity and current density. After 90 days from the installation of cathodic protection system, it could confirm that proper corrosion protection effect was obtained by considering the result of tests.

• 한국지반공학회논문집
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• 제18권1호
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• pp.5-16
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• 2002

본 연구에서는 직경 1,000mm의 시험말뚝에 대한 압축정재하시험 수행시 반력말뚝으로 사용된 직경 2,500mm의 대구경 경사반력소켓말뚝의 인발거동을 분석하였다. 경사반력말뚝은 풍화암층과 연암층 10m에 걸쳐서 현장타설말뚝으로 소켓되어졌으며, 강관부는 강관과 속채움콘크리트로, 그리고 소켓부는 콘크리트와 철근으로 구성되었다. 각 구성부재에 작용하는 변형율을 측정하기 위해 센서를 설치하였으며, 반력말뚝두부의 인발량을 측정하기 위하여 LVDT를 설치하였다. 정재하시험중 재하된 최대인발하중은 10MN이었으며 최대인발변위는 7m, 잔류인발변위는 최대 1mm 정도 발생하였다. 인발하중의 83%를 풍화암층에서 그리고 12%를 연암층에서 지지하는 것으로 나타났으며 풍화암에 소켓된 철근콘크리트부와 연암에 소켓된 털근콘크리트부에서 각각 125.3kPa와 61.8kPa의 인발응력이 발생하였다. 따라서, 풍화암층에서도 인발하중을 충분하게 지지하고 있으므로 풍화암층은 마찰력을 크게 발휘하는 지지층으로 사용되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1994년도 학술발표집 신소재, 신기술에 의한 사면안정이론과 시공사례
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• pp.94-110
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• 1994

본 연구에서는 Wright 등이 제안한 산사태 억지벽체공법에, nailing system을 추가한 새로운 형태의 사면보강공법을 제시하였다. 이를 위해, nail로 보강된 콘크리트판넬에 작용하는 토압산정법의 제시 및 억지말뚝 해석법의 정립 등이 이루어 졌다 또한 제시된 토압산정법을 토대로 nail의 효율적인 배치형태 및 설치각도 등에 대한 분석과, 콘크리트 판넬 및 억지말뚝 등으로 구성된 억지벽체의 최적설치위치에 관한 FLAC 프로그램 분석 등이 수행되었다. 이외에도 본 공법의 시공개요를 제시하였으며, 아울러 설계예를 통한 Wright 등의 제안방법과의 비교, 억지말뚝 상호간섭작용의 영향검토 등이 포함되었다.

• Structural Engineering and Mechanics
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• 제4권3호
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• pp.227-242
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• 1996

An important class of problems in the field of geotechnical engineering may be analyzed with the aid of a simple integro-differential equation. Behavior of "rigid" piles(say concrete piles), "deformable" piles(say gravel piles), pile groups, pile-raft foundations, heavily reinforced earth, flow within circular silos and down drag on cylindrical structures (for example the crusher unit of a mineral processing complex) are the type of situations that can be handled by this type of equation. The equation under consideration has the form; $$\frac{{\partial}w(r,\;z)}{{\partial}z}+f(z){\int}^z_0g({\xi})(\frac{{\partial}^2w(r,\;{\xi})}{{\partial}r^2}+\frac{1}{r}\frac{{\partial}w(r,\;{\xi})}{{\partial}r})d{\xi}+h(r,\;z)=0$$ where w(r, z) is the vertical displacement of a soil particle expressed as a function of the polar cylindrical space coordinates (r, z) and the symbols f, g and h represent soil properties and the loading conditions. The merit of the analysis is its simplicity (both in concept and in application) and the ease with which it can be expressed in a computer code. In the present paper the analysis is applied to investigate the behavior of a single rigid pile to bedrock. The emphasis, however, is placed on developing the equation, the numerical techique used in its evaluation and validation of the technique, hereafter called the ID technique, against a formal program, CRISP, which uses the FEM.

• 한국지반공학회논문집
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• 제33권12호
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• pp.81-92
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• 2017

2013년 주택법 개정에 따라 최대 3개층까지 공동주택의 수직증축 리모델링 사업이 가능해졌다. 수직증축 리모델링은 추가하중으로 인한 구조 안전성 및 강화된 내진기준을 만족해야 하므로 기초보강을 필요로 하며, 말뚝 보강설계에서는 기존 말뚝과 보강 말뚝의 하중분담을 고려해야 한다. 말뚝의 하중분담을 계산하기 위해서는 말뚝의 수직 강성($K_v$)이 필요하지만, 20~30년 전에 설치된 PC 말뚝 강성에 대한 연구는 매우 미미한 실정이다. 본 논문에서는 1990년대 아파트 신축시 수행된 38건의 현장 말뚝재하 시험 결과를 검토하여, 직경 및 길이의 변화에 따른 PC말뚝의 강성을 분석하였다. 분석 결과 말뚝강성은 장경비(L/D)가 증가함에 따라 감소하는 것으로 나타났다. 또한, 현장 말뚝재하 시험결과를 도로교설계기준해설(2008) 및 한국철도시설공단 말뚝기초의 설계(2012)에서 제안하고 있는 말뚝강성 산정을 위한 계수 'a'와 비교하였다. 비교결과 10