• Geomechanics and Engineering
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• 제35권2호
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• pp.195-208
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• 2023

The nodular diaphragm wall (NDW) is a novel type of foundation with favorable engineering characteristics, which has already been utilized in high-rise buildings and high-speed railways. Compared to traditional diaphragm walls, the NDW offers significantly improved vertical bearing capacity due to the presence of nodular parts while reducing construction time and excavation work. Despite its potential, research on the vertical bearing characteristics of NDW requires further study, and the investigation and visualization of its displacement pattern and failure mode are scant. Meanwhile, the measurement of the force component acting on the nodular parts remains challenging. In this paper, the vertical bearing characteristics of NDW are studied in detail through the indoor model test, and the displacement and failure mode of the foundation is analyzed using particle image velocimetry (PIV) technology. The principles and methods for monitoring the force acting on the nodular parts are described in detail. The research results show that the nodular part plays an essential role in the bearing capacity of the NDW, and its maximum load-bearing ratio can reach 30.92%. The existence of the bottom nodular part contributes more to the bearing capacity of the foundation compared to the middle nodular part, and the use of both middle and bottom nodular parts increases the bearing capacity of the foundation by about 9~12% compared to a single nodular part of the NDW. The increase in the number of nodular parts cannot produce a simple superposition effect on the resistance born by the nodular parts since the nodular parts have an insignificant influence on the exertion and distribution of the skin friction of NDW. The existence of the nodular part changes the displacement field of the soil around NDW and increases the displacement influence range of the foundation to a certain extent. For NDWs with three different nodal arrangements, the failure modes of the foundations appear to be local shear failures. Overall, this study provides valuable insights into the performance and behavior of NDWs, which will aid in their effective utilization and further research in the field.

• 한국공간구조학회논문집
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• 제20권4호
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• pp.169-176
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• 2020

When an unexpected excessive seismic load is applied to the base isolation of arch structure, the seismic displacement of the base isolation may be very large beyond the limit displacement of base isolation. These excessive displacement of the base isolation causes a large displacement in the upper structure and large displacement of upper structure causes structural damage. Therefore, in order to limit the seismic displacement response of the base isolation, it is necessary to install an additional device such as an anti-uplift device to the base isolation. In this study, the installation direction of the base isolation and the control performance of the base isolation installed anti-uplift device were investigated. The installation direction of the base isolation of the arch structure is determined by considering the horizontal and vertical reaction forces of the arch structure. In addition, the separation distance of the anti-uplift device is determined in consideration of the design displacement of the base isolation and the displacement of the arch structure.

• 한국제4기학회지
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• 제18권2호통권23호
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• pp.5-16
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• 2004

The geomorphic deformation of the alluvial fans by tectonic movement was investigated along the lineaments of the northem part of the Ulsan(Bulguksa) fault system. Based on the aerial photographs interpretation and field surveys Ulsan fault system was identified as an active reverse fault which has displaced the Quatemary fan deposits. Buguksa fault system strikes for the direction of NW-SE and N-S. These two lineaments of active fault are crossing at Jinty village in Gyeongju city and the fault plane forms here almost vertical dip. The lateral pressures from the two directions have possibly influenced on the formation of the vertical dip at jinty villagy. It should be resulted from that the two pressures responsible for the active reverse fault at which the one with the NW-SE strike thrusts the hanging wall of Tohamsan block southwestward and the other pressure with the N-S strike thrusts it westward over the foot wall of the fan deposits. The marine oxygen isotope stage 8(0.30-0.25 Ma. BP) and stage 6(0.20-0.14 Ma. BP) are presumed to be the ages of high and middle surfaces of the alluvial fan, repectively. The vertical displacements on the high surfaces along the Bulguksa fault system are about 1.05 m at Ha-Dong, 9.5-10.5 m at Jinhyun-Dong, and about 10 m high at Jinty village. And the vertical displacement on the middle surface was measured about 6 m high at Ha-Dong. The average slip rate of vertical displacements is calculated about 0.03-0.43 mm/y.

• 센서학회지
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• 제13권2호
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• pp.101-109
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• 2004

This paper presents a novel z-axis accelerometer with perfectly aligned vertical combs fabricated using the extended sacrificial bulk micromachining (extended SBM) process. The z-axis accelerometer is fabricated using only one (111) SOI wafer and two photo masks without wafer bonding or CMP processes as used by other research efforts that involve vertical combs. In our process, there is no misalignment in lateral gap between the upper and lower comb electrodes, because all critical dimensions including lateral gaps are defined using only one mask. The fabricated accelerometer has the structure thickness of $30{\mu}m$, the vertical offset of $12{\mu}m$, and lateral gap between electrodes of $4{\mu}m$. Torsional springs and asymmetric proof mass produce a vertical displacement when an external z-axis acceleration is applied, and capacitance change due to the vertical displacement of the comb is detected by charge-to-voltage converter. The signal-to-noise ratio of the modulated and demodulated output signal is 80 dB and 76.5 dB, respectively. The noise equivalent input acceleration resolution of the modulated and demodulated output signal is calculated to be $500{\mu}g$ and $748{\mu}g$. The scale factor and linearity of the accelerometer are measured to be 1.1 mV/g and 1.18% FSO, respectively.

• Smart Structures and Systems
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• 제26권2호
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• pp.195-211
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• 2020

Among anti-seismic technologies, base isolation is a very effective means of mitigating damage to structural and nonstructural components, such as equipment. However, most seismic isolation systems are designed for mitigating only horizontal seismic responses because the realization of a vertical isolation system (VIS) is difficult. The difficulty is primarily due to conflicting isolation stiffness demands in the static and dynamic states for a VIS, which requires sufficient rigidity to support the self-weight of the isolated object in the static state, but sufficient flexibility to lengthen the isolation period and uncouple the ground motion in the dynamic state. To overcome this problem, a semi-active VIS, called the piezoelectric inertia-type vertical isolation system (PIVIS), is proposed in this study. PIVIS is composed of a piezoelectric friction damper (PFD) and a leverage mechanism with a counterweight. The counterweight provides an uplifting force in the static state and an extra inertial force in the dynamic state; therefore, the effective vertical stiffness of PIVIS is higher in the static state and lower in the dynamic state. The PFD provides a controllable friction force for PIVIS to further prevent its excessive displacement. For experimental verification, a shaking table test was conducted on a prototype PIVIS controlled by a simple controller. The experimental results well agree with the theoretical results. To further investigate the isolation performance of PIVIS, the seismic responses of PIVIS were simulated numerically by considering 14 vertical ground motions with different characteristics. The responses of PIVIS were compared with those of a traditional VIS and a passive system (PIVIS without control). The numerical results demonstrate that compared with the traditional and passive systems, PIVIS can effectively suppress isolation displacement in all kinds of earthquake with various peak ground accelerations and frequency content while maintaining its isolation efficiency. The proposed system is particularly effective for near-fault earthquakes with long-period components, for which it prevents resonant-like motion.

• 대한지리학회지
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• 제34권3호
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• pp.231-246
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• 1999

The geomorphic deformation of the alluvial fans by tectonic movement was investigated along the lineaments of the northern part of the Bulguksa fault system. Based on the aerial photographs interpretation and field surveys Bulguksa fault system was identified as an active reverse fault which has displaced the Quaternary fan deposits. Bulguksa fault system strikes for the direction of NW-SE and N-S. These two lineaments of active fault are crossing at Jinty village in Kyungju city and the fault plane forms here almost vertical dip. Thelateral pressures from the two directions have possibly influenced on the formation of the vertical dip at Jinty village. It should be resulted from that the two pressures responsible for the active reverse fault at which the one with the NW-SE strike thrusts the hanging wall of Tohamsan block southwestward and the other pressure with the N-S jstrike thrusts it westwrd over the foot wall of the fan deposits. The marine oxygen isotope stage 8(0.30-0.25 Ma. BP) and stage 6(0.20-0.14 Ma. BP) are presumed to be the ages of high and middle surfaces of the alluvial fan, repectively. The vertical dispiacements on the high surface along the Bulguksa fault system are about 10.5m at Ha-dong, 9.5-10.5m at Jinhyun-dong, and about 10m at Jinty village. And the vertical displacement on the middle surface was measured about 6m high at Ha-dong. The average slip rate of vertical displacements is calculated about 0.03-0.043mm/y.

• Geomechanics and Engineering
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• 제36권6호
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• pp.545-561
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• 2024

Piled raft foundation has become widely used in the recent years because it can increase bearing capacity of foundation with control settlement. The design for a piled raft in terms vertical load and lateral load need to understands contribution load behavior to raft and pile in piled raft foundation system. The load-bearing behavior of the piled raft, especially concerning lateral loads, is highly complex and challenge to analyze. The complex mechanism of piled rafts can be clarified by using three dimensional (3-D) Finite Element Method (FEM). Therefore, this paper focuses on free-standing head pile group, on-ground piled raft, and embedded raft for the piled raft foundation systems. The lateral resistant of piled raft foundation was investigated in terms of relationship between vertical load, lateral load and displacement, as well as the lateral load sharing of the raft. The results show that both vertical load and raft position significantly impact the lateral load capacity of the piled raft, especially when the vertical load increases and the raft embeds into the soil. On the same condition of vertical settlement and lateral displacement, piled raft experiences a substantial demonstrates a higher capacity for lateral load sharing compared to the on-ground raft. Ultimately, regarding design considerations, the piled raft can reliably support lateral loads while exhibiting behavior within the elastic range, in which it is safe to use.

• 한국운동역학회지
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• 제20권4호
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• pp.355-364
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• 2010

The purpose of this study was to investigate the kinematical analysis of T-stop motion by inline skate rolling speed. Six subjects were participated in the experiment(age: $35.0{\pm}3.3$ yrs, weight: $72.70{\pm}5.1\;kg$, height: $176.30{\pm}3.1\;cm$, career: $10.00{\pm}2.5$ yrs). The study method adopted 3-dimensional analysis and 2 cameras for filming to analyze the required displacement of center of mass, displacement of right and left hip joint, displacement of right and left knee joint, displacement of trunk tilt using by APAS. The results were as follows; In anterior-posterior displacement of COM, the faster rolling speed, the longer displacement at phase 2. In vertical displacement of COM, the faster rolling speed, the lower displacement. In medial-lateral displacement of COM, there was no significant on rolling speed. In angular displacement of right thigh segment, the faster rolling speed, the bigger displacement in X and Z axis. In angular displacement of left thigh segment, the faster rolling speed, the lower displacement in X axis. In angular displacement of right shank segment, the faster rolling speed, the bigger displacement in Z axis. In angular displacement of left shank segment, the faster rolling speed, the bigger displacement in X and Y axis. In angular displacement of trunk segment, the faster rolling speed, the bigger displacement in Z axis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.932-939
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• 2005

Recently, the lateral displacement of the passive piles which installed under the revetment on soft ground is very important during the land reclamation work along the coastal line. The revetment on the soft clay develops the lateral displacement of the ground when the revetment loading is exceeded a certain limit. The lateral displacement of ground causes an excessive deformation of under structure itself and develops lateral earth pressure against the pile foundation as well. Especially passive piles subjected to lateral earth pressures are likely to have excessive horizontal displacement and large bending moment, which induces structural failure of pile foundation and harmful effects on superstructure. The subject of study is to investigate the later displacement of pile foundation during the construction of container terminal at the south port of Incheon. Actual field measurement data and finite element method(FEM) by AFFIMEX Ver 3.4 were used to analyze the displacement of pile and the vertical settlement of soft ground. This analysis was carried out at each sequence of construction work.

• Steel and Composite Structures
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• 제16권2호
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• pp.117-133
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• 2014

Natural vibration of truss cable structures is analyzed based upon the general structural analysis software ANSYS, energy variational method and Rayleigh method, the calculated results of three methods are compared, from which the characteristics of free-vibration are obtained. Moreover, vertical seismic response analysis of truss cable structures is carried out via time-history method. Introducing three natural earthquake waves calculated the results including time-history curve of vertical maximal displacement, time-history curve of maximal internal force. Variation curve of maximal displacement of node along span, and variation curve of maximal internal force of member along span are presented. The results show the formulas of frequencies for truss cable structures obtained by energy variational method are of high accuracy. Furthermore, the maximal displacement and the maximal internal force occur near the 1/5 span point. These provide convenient and simple design method for practical engineering.