scholarly journals ANALISIS DEFORMASI LATERAL GRUP PONDASI TIANG DENGAN PERKUATAN MENGGUNAKAN TIANG MIRING (BATTER PILES) PADA JEMBATAN DERMAGA

2021 ◽  
Vol 25 (1) ◽  
pp. 10
Author(s):  
Wirman Hidayat
Keyword(s):  
Vertical Direction ◽  
Deformation Analysis ◽  
Lateral Deformation ◽  
Lateral Resistance ◽  
Bridge Structures ◽  
The Stability ◽  
Group Piles ◽  
Reinforcement Design ◽  
Batter Piles ◽  
Safety Limit

ABSTRACT: Lateral deformation of group piles foundation is one of the parameters that must be considered properly, excessive lateral deformation can cause damage to the structure. In bridge structures, cases of excessive lateral deformation often occur which potentially affect the reliability of the bridge and cause damage to the structure. When the lateral deformation that occurs in the foundation group exceeds the safety limit, it needs additional reinforcement designed to provide additional lateral resistance, so that the deformation that occurs can be reduced and the strength of the structure also increases. Reinforcement using inclined piles (batter piles) can be used in increasing the lateral resistance of the group piles foundation. The use of batter piles mechanically distributes the horizontal load to the vertical direction of the foundation, so that the lateral load that carried by the foundation is distributed into vertical and horizontal components, to reduce the lateral deformation that occurs. In this study, the lateral deformation analysis was carried out on the group piles foundation on the jetty bridge which experienced a large deformation, then a reinforcement design was designed using batter piles to increase lateral resistance. The analysis was performed using PLAXIS 2D and GROUP software. From the analysis, it was found that reinforcement using batter piles can reduce the lateral deformation that occurs and increase the stability of the bridge..Keywords: batter piles, lateral deformation, lateral resistance

The Stability Analysis of Slope of Shegang Protecting Dyke

2011 ◽  
Vol 261-263 ◽  
pp. 1841-1845
Author(s):  
Hui Qin Yao
Keyword(s):  
Stability Analysis ◽  
Working Conditions ◽  
Saturation Line ◽  
Dam Safety ◽  
Design Code ◽  
Embankment Dam ◽  
Safe Operation ◽  
Calculation Results ◽  
The Stability ◽  
Reinforcement Design

Appraisal of dam slope safety is essential for security and stability of the dyke that has been constructed for many years. According to the requirements of the appraisal of dam safety, the stability analysis of slope of Shegang dyke has been carried out by using Sweden circular-arc method, Bishop method, Engineer Corps method and Lowe method four methods under many kinds of working conditions and some conditions when the saturation line raising. Combined with the design code form embankment dam, the calculation results can be analyzed. The analysis can show that the security indexes of anti-slide under four kinds of working conditions and some conditions when the saturation line raising meet the requirements of the design code. This can provide basis for the reinforcement design of the dam, which also has a certain directive significance for the safe operation and observation of the dam in the future.

scholarly journals The linear instability of the stratified plane Couette flow

2018 ◽  
Vol 853 ◽  
pp. 205-234 ◽  
Author(s):  
Giulio Facchini ◽  
Benjamin Favier ◽  
Patrice Le Gal ◽  
Meng Wang ◽  
Michael Le Bars
Keyword(s):  
Reynolds Number ◽  
Stability Analysis ◽  
Numerical Simulations ◽  
Couette Flow ◽  
Vertical Direction ◽  
Stability Diagram ◽  
Linear Instability ◽  
Plane Couette Flow ◽  
Horizontal Shear ◽  
The Stability

We present the stability analysis of a plane Couette flow which is stably stratified in the vertical direction orthogonal to the horizontal shear. Interest in such a flow comes from geophysical and astrophysical applications where background shear and vertical stable stratification commonly coexist. We perform the linear stability analysis of the flow in a domain which is periodic in the streamwise and vertical directions and confined in the cross-stream direction. The stability diagram is constructed as a function of the Reynolds number $Re$ and the Froude number $Fr$, which compares the importance of shear and stratification. We find that the flow becomes unstable when shear and stratification are of the same order (i.e. $Fr\sim 1$) and above a moderate value of the Reynolds number $Re\gtrsim 700$. The instability results from a wave resonance mechanism already known in the context of channel flows – for instance, unstratified plane Couette flow in the shallow-water approximation. The result is confirmed by fully nonlinear direct numerical simulations and, to the best of our knowledge, constitutes the first evidence of linear instability in a vertically stratified plane Couette flow. We also report the study of a laboratory flow generated by a transparent belt entrained by two vertical cylinders and immersed in a tank filled with salty water, linearly stratified in density. We observe the emergence of a robust spatio-temporal pattern close to the threshold values of $Fr$ and $Re$ indicated by linear analysis, and explore the accessible part of the stability diagram. With the support of numerical simulations we conclude that the observed pattern is a signature of the same instability predicted by the linear theory, although slightly modified due to streamwise confinement.

scholarly journals Spatial Data Analysis for Deformation Monitoring of Bridge Structures

2020 ◽  
Vol 10 (23) ◽  
pp. 8731
Author(s):  
Ján Erdélyi ◽  
Alojz Kopáčik ◽  
Peter Kyrinovič
Keyword(s):  
Spatial Data ◽  
Laser Scanning ◽  
Deformation Monitoring ◽  
Radar Interferometry ◽  
Spatial Data Analysis ◽  
Deformation Analysis ◽  
Measuring Instruments ◽  
Engineering Structures ◽  
Essential Information ◽  
Bridge Structures

Weather conditions and different operational loads often cause changes in essential parts of engineering structures, and this affects the static and dynamic behavior and reliability of these structures. Therefore, geodetic monitoring is an integral part of the diagnosis of engineering structures and provides essential information about the current state (condition) of the structure. The development of measuring instruments enables deformation analyses of engineering structures using non-conventional surveying methods. Nowadays, one of the most effective techniques for spatial data collection is terrestrial laser scanning (TLS). TLS is frequently used for data acquisition in cases where three-dimensional (3D) data with high resolution is needed. Using suitable data processing, TLS can be used for static deformation analysis of the structure being monitored. For dynamic deformation measurements (structural health monitoring) of bridge structures, ground-based radar interferometry and accelerometers are often used for vibration mode determination using spectral analysis of frequencies. This paper describes experimental deformation monitoring of structures performed using TLS and ground-based radar interferometry. The procedure of measurement, the analysis of the acquired spatial data, and the results of deformation monitoring are explained and described.

Stability and Deformation Analysis for Excavation and Backfilling of Fushun West Open-Pit Coal Mine

2013 ◽  
Vol 353-356 ◽  
pp. 751-755 ◽  
Author(s):  
Yong Cheng Yan ◽  
Xian Zhang Ling ◽  
Feng Zhang ◽  
Jia Hui Wang
Keyword(s):  
Coal Mine ◽  
Slip Surface ◽  
Surrounding Rock ◽  
Open Pit ◽  
Deformation Analysis ◽  
Interface Model ◽  
Safety Coefficient ◽  
Mine Slope ◽  
The Stability ◽  
Technical Basis

Taking section W400 of Fushun west open-pit coal mine for the research, the interface model of fracture zone and surrounding rock was established. FLAC3D is used to analysis the influence of excavation and backfill of open-fit coal mine to the slope stability and deformation. The numerical results and analysis show that: (1) when the open-pit coal mine slope is excavated to final production line, the safety coefficient is 2.98, with the excavation, the deformation of the Fushun No.1 Refinery Factory area increases. (2) With the increase of backfilling, the slope coefficient increases to 3.32, this will reduce the deformation of the Fushun No.1 Refinery Factory area. Furthermore, the positions of the dangerous slip surface and serious deformation part of factory area should be regards as key areas. These conclusions could provide technical basis for the stability analysis of Fushun west open-pit coal mine.

A full-scale stability experiment on a diaphragm wall trench

2000 ◽  
Vol 37 (2) ◽  
pp. 379-392 ◽  
Author(s):  
Jiin-Song Tsai ◽  
Lee-Der Jou ◽  
Hsii-Sheng Hsieh
Keyword(s):  
Full Scale ◽  
Failure Pattern ◽  
Diaphragm Wall ◽  
Lateral Deformation ◽  
Sandy Ground ◽  
Stability Experiment ◽  
Scale Field ◽  
Slurry Trench ◽  
Scale Experiment ◽  
The Stability

This paper presents the results of a full-scale field experiment on the stability of a slurry-filled diaphragm wall trench. The objective of this experiment was to observe the failure pattern of a slurry-supported trench excavated in sandy ground. Ground responses, including settlement and lateral deformation of the surrounding ground adjacent to the experimental trench, were carefully monitored during the experiment. The stability of the trench was examined by lowering the slurry level in stages. The trench was deliberately failed. Field observations indicated that the experimental trench failed in 2 h in a progressive sliding pattern that resulted in a near-hemispherical cave-in of the adjacent ground. In this paper, a failure mechanism of the trench is proposed and an analytical method is adopted to back-analyze the stability of the trench. The stability of the trench and the failure pattern can be accurately analyzed using the method of Tsai and Chang.Key words: full-scale experiment, field test, slurry trench, stability analysis.

Dynamic Research of Knitting Element for Computerized Flat Knitting Machine Based on ANSYS/LS-DYNA

2012 ◽  
Vol 472-475 ◽  
pp. 488-493
Author(s):  
Yuan Fang ◽  
Fan Tian Xia
Keyword(s):  
Experimental Measurement ◽  
Impact Force ◽  
Vertical Direction ◽  
Displacement Velocity ◽  
Mechanic Model ◽  
Ansys Simulation ◽  
Ansys Analysis ◽  
The Stability ◽  
The Impact ◽  
Dynamic Research

Based on research on the knitting processes, an impact mechanic model for knitting elements was established to investigate the variation of the impact force in vertical direction between the cam and the select jack. The variation of the displacement, velocity, acceleration of the select jack and the stability for the needles’ moving has been confirmed by the simulation of knitting process based on the software ANSYS/LS-DYNA. Furthermore, the variation of the select jack has been confirmed by experimental measurement during the knitting process. The data of the experiment results were in accordance with the ANSYS’ simulation which verified the correctness of the ANSYS’ analysis. It provided a theoretic basis for the design of computerized flat knitting machines.

Direct numerical simulation of instabilities in a two-dimensional near-critical fluid layer heated from below

2001 ◽  
Vol 442 ◽  
pp. 119-140 ◽  
Author(s):  
S. AMIROUDINE ◽  
P. BONTOUX ◽  
P. LARROUDÉ ◽  
B. GILLY ◽  
B. ZAPPOLI
Keyword(s):  
Boundary Layer ◽  
Critical Point ◽  
Stokes Equations ◽  
Fluid Layer ◽  
Vertical Direction ◽  
Single Layer ◽  
Bulk Temperature ◽  
Two Dimensional ◽  
Piston Effect ◽  
The Stability

An analysis of the hydrodynamic stability of a fluid near its near critical point – initially at rest and in thermodynamic equilibrium – is considered in the Rayleigh–Bénard configuration, i.e. heated from below. The geometry is a two-dimensional square cavity and the top and bottom walls are maintained at constant temperatures while the sidewalls are insulated. Owing to the homogeneous thermo-acoustic heating (piston effect), the thermal field exhibits a very specific structure in the vertical direction. A very thin hot thermal boundary layer is formed at the bottom, then a homogeneously heated bulk settles in the core at a lower temperature; at the top, a cooler boundary layer forms in order to continuously match the bulk temperature with the colder temperature of the upper wall. We analyse the stability of the two boundary layers by numerically solving the Navier–Stokes equations appropriate for a van der Waals' gas slightly above its critical point. A finite-volume method is used together with an acoustic filtering procedure. The onset of the instabilities in the two different layers is discussed with respect to the results of the theoretical stability analyses available in the literature and stability diagrams are derived. By accounting for the piston effect the present results can be put within the framework of the stability analysis of Gitterman and Steinberg for a single layer subjected to a uniform, steady temperature gradient.

Consensus-Based Cooperative Formation Control for Multiquadcopter System With Unidirectional Network Connections

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Toru Namerikawa ◽  
Yasuhiro Kuriki ◽  
Ahmed Khalifa
Keyword(s):  
Cooperative Control ◽  
Horizontal Plane ◽  
Formation Control ◽  
Vertical Direction ◽  
Order System ◽  
Control Algorithms ◽  
Network Connections ◽  
Directed Spanning Tree ◽  
Aerial Vehicle ◽  
The Stability

In this paper, we consider cooperative control issues for a multi-unmanned aerial vehicle (UAV) system. We propose a cooperative formation control strategy with unidirectional network connections between UAVs. Our strategy is to apply a consensus-based algorithm to the UAVs so that they can cooperatively fly in formation. First, we show that UAV models on the horizontal plane and in the vertical direction are expressed as a fourth- and second-order system, respectively. Then, we show that the stability discriminants of the multi-UAV system on the horizontal plane and in the vertical direction are expressed as polynomials. For a network structure composed of bidirectional or unidirectional network connections under the assumption that the network has a directed spanning tree, we provide conditions for formation control gains such that all roots of the polynomials have negative real parts in order for the UAVs to asymptotically converge to the positions for a desired formation by using the generalized Routh stability criterion. The proposed control algorithms are validated through simulations, and experiments are performed on multiple commercial small UAVs to validate the proposed control algorithm.

Design and Prototype of a Two-Axis Acoustic Levitator

2016 ◽  
Author(s):  
Justin Clough ◽  
Michael W. Sracic ◽  
Daniel Piombino ◽  
Jonathan Braaten ◽  
Scott Connors ◽  
...  
Keyword(s):  
Water Droplet ◽  
Vertical Direction ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Test Stand ◽  
Frame Structure ◽  
Particle Stability ◽  
The Stability ◽  
Adequate Power ◽  
Acoustic Levitator

The purpose of this paper is to document the process required to design and prototype a two-axis acoustic levitator and to show that the two-axis levitator improves the stability of a particle in an acoustic levitation field. The levitator design consists of the following subsystems: the transducer assemblies, which are responsible for generating the acoustic pressure field needed for levitation; the electrical system, which is responsible for providing the transducer assemblies with adequate power to maintain levitation; and the frame structure, which is responsible for locating and rigidly supporting the transducer assemblies. The two-axis levitator is designed to have four transducers that operate at 27.2 kHz, and simulated results show that the system satisfies nearly all the design criteria and objectives. A transducer test stand and prototype were constructed to verify the design. The test stand was used to characterize all four transducers, and once the assembly was constructed the prototype operating frequency was determined to be 27.5 kHz. The prototype was used to successfully levitate Styrofoam pellets, a plastic pellet, and water droplets of various sizes. The displacement of a water droplet of approximately 1 mm in diameter was measured when levitated with both one-axis (vertical) and two-axis (vertical and horizontal) levitation. Using one-axis levitation, the water droplet displaced a maximum of 1.1 mm in the horizontal direction and 0.17 mm in the vertical direction. Using two-axis levitation, the horizontal displacement was 0.07 mm and the vertical displacement was 0.05 mm. Therefore, the two-axis acoustic levitator provides significant improvements in levitated particle stability.

Three-dimensional stability analysis for slurry-filled trench wall in cohesionless soil

1996 ◽  
Vol 33 (5) ◽  
pp. 798-808 ◽  
Author(s):  
Jiin-Song Tsai ◽  
Jia-Chyi Chang
Keyword(s):  
Stability Analysis ◽  
Stability Problem ◽  
Slip Surface ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Soil Mass ◽  
Cohesionless Soil ◽  
Cohesionless Soils ◽  
Slurry Trench ◽  
The Stability

On the basis of the limiting equilibrium and arching theory, a three-dimensional analysis is proposed for slurry-supported trenches in cohesionless soils. This analytical approach is developed by considering the trench stability problem as a vertical soil cut within a fictitious half-silo with a rough wall surronding. Arching effects are considered not only in the vertical direction but also in the horizontal direction. A shell-shaped slip surface of the sliding soil mass is defined by Mohr-Coulomb criterion. The factor of safety is defines as the ratio of the resisting force induced by slurry pressure to the horizontal force required to maintain the stability of the trench wall. Results of the proposed method have been compared with those of two existing analytical methods for a typical trench stability problem. Key words: stability analysis, slurry trench wall, cohesionless soil.

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