Ground Motion Intensity Measures to Evaluate II: The Performance of Shallow-Founded Structures on Liquefiable Ground

2017 ◽  
Vol 33 (1) ◽  
pp. 277-298 ◽  
Author(s):  
Zana Karimi ◽  
Shideh Dashti
Keyword(s):  
Three Dimensional ◽  
Soil Surface ◽  
Accurate Estimation ◽  
Damage Potential ◽  
Intensity Measures ◽  
Liquefaction Hazard ◽  
Story Drift ◽  
Permanent Settlement ◽  
Excess Pore Pressures ◽  
Base Rock

A reliable mitigation of the liquefaction hazard requires an accurate estimation of the consequences of liquefaction in the context of building performance. Knowledge and use of an optimal intensity measure (IM) will reduce variability and improve accuracy of the predicted measure of performance. This paper presents the results of a three-dimensional, fully coupled, nonlinear, dynamic parametric numerical simulation of shallow-founded structures on layered, liquefiable soils, previously validated with centrifuge results. The generation and redistribution of excess pore pressures as well as soil-structure interaction effects were directly considered in the simulations. The influence of different IMs recorded at the base rock, far-field soil surface, and foundation was evaluated and compared on engineering demand parameters (EDP) that relate to structural performance and damage potential, such as foundation settlement and peak, transient, inter-story drift ratios. The IMs identified with the best combination of efficiency, sufficiency, and predictability in predicting the structural EDPs of interest were identified at the base rock as: CAV and CAV5 for permanent settlement, PSA[ T STo] for total and flexural drift ratios, and PGV for rocking drift ratio.

Vector and Scalar IMs in Structural Response Estimation, Part II: Building Demand Assessment

2016 ◽  
Vol 32 (3) ◽  
pp. 1525-1543 ◽  
Author(s):  
Mohsen Kohrangi ◽  
Paolo Bazzurro ◽  
Dimitrios Vamvatsikos
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Three Dimensional ◽  
Structural Response ◽  
Response Assessment ◽  
Companion Paper ◽  
Period Range ◽  
Intensity Measures ◽  
Advantages And Disadvantages ◽  
Story Drift

The advantages and disadvantages of using scalar and vector ground motion intensity measures (IMs) are discussed for the local, story-level seismic response assessment of three-dimensional (3-D) buildings. Candidate IMs are spectral accelerations, at a single period ( Sa) or averaged over a period range ( Sa avg). Consistent scalar and vector probabilistic seismic hazard analysis results were derived for each IM, as described in the companion paper in this issue ( Kohrangi et al. 2016 ). The response hazard curves were computed for three buildings with reinforced concrete infilled frames using the different IMs as predictors. Among the scalar IMs, Sa avg tends to be the best predictor of both floor accelerations and inter story drift ratios at practically any floor. However, there is an improvement in response estimation efficiency when employing vector IMs, specifically for 3-D buildings subjected to both horizontal components of ground motion. This improvement is shown to be most significant for a tall plan-asymmetric building.

Ground Motion Intensity Measures to Evaluate I: The Liquefaction Hazard in the Vicinity of Shallow-Founded Structures

2017 ◽  
Vol 33 (1) ◽  
pp. 241-276 ◽  
Author(s):  
Shideh Dashti ◽  
Zana Karimi
Keyword(s):  
Pore Pressure ◽  
Ground Motions ◽  
Pressure Ratio ◽  
Soil Surface ◽  
Excess Pore Pressure ◽  
Far Field ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Liquefaction Hazard ◽  
Simplified Procedures

When evaluating the liquefaction hazard within a performance-based framework, whether using simplified procedures or advanced numerical tools, the hazard and its effects on structures need to be evaluated under a range of ground motions. Choice of an optimum intensity measure (IM) in the selection and scaling of ground motions will reduce variability in the predicted response, dependence on source characteristics, and uncertainty in the prediction of the IM. This paper presents the results of a numerical parametric study, validated against centrifuge results, to evaluate the influence of different IMs on the liquefaction hazard in the far-field and near shallow-founded structures. Pore pressure redistribution and soil-structure interaction were considered in estimating the liquefaction hazard in terms of peak excess pore pressure ratio ( r u,peak). The IMs at the base rock, far-field soil surface, and foundation with the best combination of efficiency, sufficiency, and predictability were evaluated and identified as: (1) pseudo-spectral acceleration at the site's initial fundamental period ( PSA Base[ T So]) for predicting r u,peak in the far-field; (2) peak ground acceleration, ( PGA Base); and Arias intensity ( AI Base) for predicting r u,peak under the foundation.

Automatic weaving method for three-dimensional composite preforms using vision system

2021 ◽  
pp. 004051752098238
Author(s):  
Siyuan Li ◽  
Zhongde Shan ◽  
Dong Du ◽  
Li Zhan ◽  
Zhikun Li ◽  
...  
Keyword(s):  
Relative Position ◽  
Vision System ◽  
Estimation Error ◽  
Three Dimensional ◽  
Fiber Reinforced Composites ◽  
Accurate Estimation ◽  
Digital Manufacturing ◽  
Relative Rotation ◽  
Reinforced Composites ◽  
Main Structure

Three-dimensional composite preform is the main structure of fiber-reinforced composites. During the weaving process of large-sized three-dimensional composite preform, relative rotation or translation between the fiber feeder and guided array occurs before feeding. Besides, the weaving needles can be at different heights after moving out from the guided array. These problems are mostly detected and adjusted manually. To make the weaving process more precise and efficient, we propose machine vision-based methods which could realize accurate estimation and adjustment of the relative position-pose between the fiber feeder and guided array, and make the needles pressing process automatic by recognizing the position of the weaving needles. The results show that the estimation error of relative position-pose is within 5%, and the rate of unrecognized weaving needles is 2%. Our proposed methods improve the automation level of weaving, and are conducive to the development of preform forming toward digital manufacturing.

“A NOVEL ATTEMPT IN ESTIMATION OF FETAL WEIGHT USING NEW SOFT TISSUE MEASUREMENTS”

2021 ◽  
pp. 1-3
Author(s):  
Sathyan Gnanasigamani ◽  
Sudhakar Vadivel ◽  
Bala Subramaniam ◽  
Sakthivel Raja Ganesan ◽  
Pradeebaa Thiyagarajan ◽  
...  
Keyword(s):  
Birth Weight ◽  
Soft Tissue ◽  
Strong Predictor ◽  
Three Dimensional ◽  
Fetal Weight ◽  
Ultrasound Measurement ◽  
Accurate Estimation ◽  
Tissue Thickness ◽  
Third Trimester ◽  
Soft Tissue Thickness

Background: The Accurate estimation of fetal weight is important in modern obstetrics. Currently, Hadlock's formula is used widely for fetal weight estimation, which includes BPD, AC, FL and HC. The correct plane of measurement of various standard parameters is difcult to obtain especially in third trimester. Hence soft tissue thicknesses of the fetus are tested for correlation with birth weight in this study. Materials & Methods: A prospective observational study conducted among 90 pregnant females referred for Ultrasound examination in the third trimester with an interval from the ultrasound scan to delivery of ≤7 days from 2019 to 2020. Results: The measurements of abdominal, fetal mid-thigh and mid-arm soft tissue thicknesses correlated well with birth weight in a high statistically signicant positive linear relationship. A new regression model developed out of the soft tissue thicknesses(FASTT, FMASTT, FTSTT) correlates better than the Hadlock's model and Sujitkumar Hiwale et al model (For Indian population) based on BPD, HC, AC and FL Conclusion: Ultrasound measurement of soft tissue thickness may prove to be a strong predictor of fetal weight essential for sonographic assessment of pregnancy. They are easy and simple hence fetal soft tissue thickness measurements, both two- and three-dimensional, may prove to be a diagnostic parameter that has as small an error rate as possible, is quick to use and reproducible by different examiners

scholarly journals GEOtop 2.0: simulating the combined energy and water balance at and below the land surface accounting for soil freezing, snow cover and terrain effects

2014 ◽  
Vol 7 (6) ◽  
pp. 2831-2857 ◽  
Author(s):  
S. Endrizzi ◽  
S. Gruber ◽  
M. Dall'Amico ◽  
R. Rigon
Keyword(s):  
Snow Cover ◽  
Land Surface ◽  
Three Dimensional ◽  
Soil Surface ◽  
Soil Freezing ◽  
Energy Budgets ◽  
Freezing And Thawing ◽  
Terrain Effects ◽  
Synthetic Simulation ◽  
Soil Freezing And Thawing

Abstract. GEOtop is a fine-scale grid-based simulator that represents the heat and water budgets at and below the soil surface. It describes the three-dimensional water flow in the soil and the energy exchange with the atmosphere, considering the radiative and turbulent fluxes. Furthermore, it reproduces the highly non-linear interactions between the water and energy balance during soil freezing and thawing, and simulates the temporal evolution of the water and energy budgets in the snow cover and their effect on soil temperature. Here, we present the core components of GEOtop 2.0 and demonstrate its functioning. Based on a synthetic simulation, we show that the interaction of processes represented in GEOtop 2.0 can result in phenomena that are significant and relevant for applications involving permafrost and seasonally frozen soils, both in high altitude and latitude regions.

Evolutionary Algorithm Based Solution of Rössler Chaotic System Using Bernstein Polynomials

2020 ◽  
Vol 17 (7) ◽  
pp. 2932-2939
Author(s):  
Rania A. Alharbey ◽  
Kiran Sultan
Keyword(s):  
Chaotic System ◽  
Fitness Function ◽  
Bernstein Polynomials ◽  
Three Dimensional ◽  
Accurate Estimation ◽  
Interior Point Algorithm ◽  
Research Attention ◽  
Rossler System ◽  
Rössler System ◽  
Error Dynamics

Chaotic systems have gained enormous research attention since the pioneering work of Lorenz. Rössler system stands among the extensively studied classical chaotic models. This paper proposes a technique based on Bernstein Polynomial Basis Function to convert the three-dimensional Rössler system of Ordinary Differential Equations (ODEs) into an error minimization problem. First, the properties of Bernstein Polynomials are applied to derive the fitness function of Rössler chaotic system. Second, in order to obtain the values of unknown Bernstein coefficients to optimize the fitness function, the problem is solved using two versatile algorithms from the family of Evolutionary Algorithms (EAs), Genetic Algorithm (GA) hybridized with Interior Point Algorithm (IPA) and Differential Algorithm (DE). For validity of the proposed technique, simulation results are provided which verify the global stability of error dynamics and provide accurate estimation of the desired parameters.

Intensity measures for seismic liquefaction hazard evaluation of sloping site

2015 ◽  
Vol 22 (10) ◽  
pp. 3999-4018 ◽  
Author(s):  
Zhi-xiong Chen ◽  
Yin Cheng ◽  
Yang Xiao ◽  
Liang Lu ◽  
Yang Yang
Keyword(s):  
Hazard Evaluation ◽  
Intensity Measures ◽  
Seismic Liquefaction ◽  
Liquefaction Hazard

Numerical Assessment of Thermal Response Associated With In Vivo Skin Electroporation: The Importance of the Composite Skin model

2006 ◽  
Vol 129 (3) ◽  
pp. 330-340 ◽  
Author(s):  
S. M. Becker ◽  
A. V. Kuznetsov
Keyword(s):  
Three Dimensional ◽  
Thermal Response ◽  
Physical Parameters ◽  
Damage Potential ◽  
Electric Pulses ◽  
Large Molecules ◽  
Composite Layers ◽  
Thermal Tissue Damage ◽  
Pass Through

Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. The structure of the transport inhibiting outer layer, the stratum corneum, is temporarily destabilized due to the development of microscopic pores. Consequently agents that are ordinarily unable to pass into the skin are able to pass through this outer barrier. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with Joule heating. This paper shows the importance of using a composite model in calculating the electrical and thermal effects associated with skin electroporation. A three-dimensional transient finite-volume model of in vivo skin electroporation is developed to emphasize the importance of representing the skin’s composite layers and to illustrate the underlying relationships between the physical parameters of the composite makeup of the skin and resulting thermal damage potential.

The Improvement to the Environmental Wind and Tropical Cyclone Circulation Retrievals with the Modified GBVTD (MGBVTD) Technique

2013 ◽  
Vol 52 (11) ◽  
pp. 2493-2508 ◽  
Author(s):  
Xiaomin Chen ◽  
Kun Zhao ◽  
Wen-Chau Lee ◽  
Ben Jong-Dao Jou ◽  
Ming Xue ◽  
...  
Keyword(s):  
Inner Core ◽  
Doppler Radar ◽  
Three Dimensional ◽  
Radar Data ◽  
Accurate Estimation ◽  
Doppler Radar Data ◽  
Tangential Wind ◽  
The Mean ◽  
Landfalling Tropical Cyclones ◽  
Beam Component

AbstractThe ground-based velocity track display (GBVTD) was developed to deduce a three-dimensional primary circulation of landfalling tropical cyclones from single-Doppler radar data. However, the cross-beam component of the mean wind cannot be resolved and is consequently aliased into the retrieved axisymmetric tangential wind . Recently, the development of the hurricane volume velocity processing method (HVVP) enabled the independent estimation of ; however, HVVP is potentially limited by the unknown accuracy of empirical assumptions used to deduce the modified Rankine-combined vortex exponent . By combing the GBVTD with HVVP techniques, this study proposes a modified GBVTD method (MGBVTD) to objectively deduce from the GBVTD technique and provide a more accurate estimation of and via an iterative procedure to reach converged and cross-beam component of solutions. MGBVTD retains the strength of both algorithms but avoids their weaknesses. The results from idealized experiments demonstrate that the MGBVTD-retrieved cross-beam component of is within 2 m s−1 of reality. MGBVTD was applied to Hurricane Bret (1999) whose inner core was captured simultaneously by two Weather Surveillance Radar-1988 Doppler (WSR-88D) instruments. The MGBVTD-retrieved cross-beam component of from single-Doppler radar data is very close to that from dual-Doppler radar synthesis using extended GBVTD (EGBVTD); their difference is less than 2 m s−1. The mean difference in the MGBVTD-retrieved from the two radars is ~2 m s−1, which is significantly smaller than that resolved in GBVTD retrievals (~5 m s−1).

Shaking Table Test of Muti-Story Subway Station Considering Soil-Structure Interaction

2013 ◽  
Vol 694-697 ◽  
pp. 321-324 ◽  
Author(s):  
Shu Wei Wang ◽  
Ying Ming Zhou ◽  
Shu Yun Mi
Keyword(s):  
Seismic Waves ◽  
Shaking Table Test ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Soil Surface ◽  
Shaking Table ◽  
Subway Station ◽  
Acceleration Process ◽  
Underground Structures

In this paper, a three-dimensional shaking table test of three three-span subway station model is done. Three test seismic waves were selected in this experiment, which were applied to the model. Modal analysis of the structure was done, and the determination of the acceleration of the model structure was obtained. And the law of underground structures under earthquake damage was analysis. Soil surface acceleration process and its response spectrum and strain are obtained in the different amplitudes of ground motion input case. From experiment cracks in the emergence and development of the situation were observed, and which gives recommendations for the seismic design of underground structures.

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