Search results for: framed structures

Authors: Barbora Svechova, Monika Licbinska

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Geochemical modeling of mineralogical changes of various materials in contact with an aqueous solution is an important tool for predicting the processes and development of given materials at the site. The modeling focused on the mutual interaction of groundwater at the contact with the rock mass and its subsequent influence on concrete structures. The studied locality is located in Slovakia in the area of the Liptov Basin, which is a significant inter-mountain lowland, which is bordered on the north and south by the core mountains belt of the Tatras, where in the center the crystalline rises to the surface accompanied by Mesozoic cover. Groundwater in the area is bound to structures with complicated geological structures. From the hydrogeological point of view, it is an environment with a crack-fracture character. The area is characterized by a shallow surface circulation of groundwater without a significant collector structure, and from a chemical point of view, groundwater in the area has been classified as calcium bicarbonate with a high content of CO2 and SO4 ions. According to the European standard EN 206-1, these are waters with medium aggression towards the concrete. Three rock samples were taken from the area. Based on petrographic and mineralogical research, they were evaluated as calcareous shale, micritic limestone and crystalline shale. These three rock samples were placed in demineralized water for one month and the change in the chemical composition of the water was monitored. During the solution-rock interaction there was an increase in the concentrations of all major ions, except nitrates. There was an increase in concentration after a week, but at the end of the experiment, the concentration was lower than the initial value. Another experiment was the interaction of groundwater from the studied locality with a concrete structure. The concrete sample was also left in the water for 1 month. The results of the experiment confirmed the assumption of a reduction in the concentrations of calcium and bicarbonate ions in water due to the precipitation of amorphous forms of CaCO3 on the surface of the sample.Vice versa, it was surprising to increase the concentration of sulphates, sodium, iron and aluminum due to the leaching of concrete. Chemical analyzes from these experiments were performed in the PHREEQc program, which calculated the probability of the formation of amorphous forms of minerals. From the results of chemical analyses and hydrochemical modeling of water collected in situ and water from experiments, it was found: groundwater at the site is unsaturated and shows moderate aggression towards reinforced concrete structures according to EN 206-1a, which will affect the homogeneity and integrity of concrete structures; from the rocks in the given area, Ca, Na, Fe, HCO3 and SO4. Unsaturated waters will dissolve everything as soon as they come into contact with the solid matrix. The speed of this process then depends on the physicochemical parameters of the environment (T, ORP, p, n, water retention time in the environment, etc.).

Keywords: geochemical modeling, concrete , dissolution , PHREEQc

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Authors: Jinkoo Kim, Minsung Kim

Abstract:

This study develops a hybrid seismic energy dissipation device composed of a viscoelastic damper and a steel slit damper connected in parallel. A cyclic loading test is conducted on a test specimen to validate the seismic performance of the hybrid damper. Then a moment-framed model structure is designed without seismic load so that it is retrofitted with the hybrid dampers. The model structure is transformed into an equivalent simplified system to find out optimum story-wise damper distribution pattern using genetic algorithm. The effectiveness of the hybrid damper is investigated by fragility analysis and the life cycle cost evaluation of the structure with and without the dampers. The analysis results show that the model structure has reduced probability of reaching damage states, especially the complete damage state, after seismic retrofit. The expected damage cost and consequently the life cycle cost of the retrofitted structure turn out to be significantly small compared with those of the original structure. Acknowledgement: This research was supported by the Ministry of Trade, Industry and Energy (MOTIE) and Korea Institute for Advancement of Technology (KIAT) through the International Cooperative R & D program (N043100016).

Keywords: seismic retrofit, slit dampers, friction dampers, hybrid dampers

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Authors: Putul Haldar, Yogendra Singh, D. K. Paul

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Un-Reinforced Masonry (URM) infilled RC framed buildings are the most common construction practice for modern multi-storey buildings in India like many other parts of the world. Although the behavior and failure pattern of the global structure changes significantly due to infill-frame interaction, the general design practice is to treat them as non-structural elements and their stiffness, strength and interaction with frame is often ignored, as it is difficult to simulate. Indian Standard, like many other major national codes, does not provide any explicit guideline for modeling of infills. This paper takes a stock of controlling design provisions in some of the major national seismic design codes (BIS 2002; CEN 2004; NZS-4230 2004; ASCE-41 2007) to ensure the desired seismic performance of infilled frame. Most of the national codes on seismic design of buildings still lack in adequate guidelines on modeling and design of URM infilled frames results in variable assumption in analysis and design. This paper, using nonlinear pushover analysis, also presents the effect of one of such assumptions of conventional ‘simultaneous’ analysis procedure of infilled frame on the seismic performance of URM infilled RC frame buildings.

Keywords: URM infills, RC frame, seismic design codes, construction sequence of infilled frame

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Authors: Mahdi Almaky

Abstract:

Conducting polymer of N-(3-pyrrol-1-yl-propyl)-2,2`-bipyridinium hexafluoro-phosphate (PPBH) was prepared via chemical and electrochemical polymerization methods. The bulk polymer showed conductivity in the order of 10-12 S cm-1. DNA-templated polymer nano wires of PPBH (PolyPPBH-DNA) have been chemically prepared then used as templates to direct the formation of metal nanowires (Cu) in order to enhance the electrical properties of the polymer/DNA wires. The chemical structures, morphology and the electrical characterisation of the as obtained structures have been characterized through spectroscopic (FTIR, UV-vis and XPS), single-crystal X-ray diffraction and microscopic (AFM, EFM and c-AFM) techniques. The morphology of the nanomaterials has been observed by AFM; showing the nanowires are uniform and continuous. The polymer conductivity was slightly improved after metallization. The conductivity of Cu-PolyPPBH-DNA nanowires was estimated to be 7.1x10-2 S cm-1. This conductivity is slightly higher than the conductivity of PolyPPBH-DNA nano wires (2.0 x 10-2 S cm-1), but it is lower than the measurements for PPy/DNA nano wires (2.1 x 10-1 S cm-1) prepared and measured by using c-AFM probe. These results reflect the large effect of the chemical structure (N-substitution) on the electrical properties of these polymers by reducing the extended conjugation.

Keywords: DNA, template, nano wires, N-Alkylatedpyrrole, copper

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Authors: Hajnalka Szarvas

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The research examines the effectiveness of e-participation tools and methods from a point of view of cultural fitting to the Hungarian community traditions. Participation can have very different meanings depending on the local cultural and historical traditions, experiences of the certain societies. Generally when it is about e-democracy or e-participation tools most of the researches are dealing with its technological sides and novelties, but there is not much said about the cultural and social context of the different platforms. However from the perspective of their success it would be essential to look at the human factor too, the actual users, how the certain DMS or any online platform is fitting to the way of thought, the way of functioning of the certain society. Therefore the paper will explore that to what extent the different online platforms like Loomio, Democracy OS, Your Priorities EVoks, Populus, miutcank.hu, Liquid Democracy, Brain Bar Budapest Lab are compatible with the Hungarian mental structures and community traditions, the contents of collective mind about community functioning. As a result the influence of cultural embeddedness of the logic of e-participation development tools on success of these methods will be clearly seen. Furthermore the most crucial factors in general which determine the efficiency of e-participation development tools in Hungary will be demonstrated.

Keywords: cultural embeddedness, e-participation, local community traditions, mental structures

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Authors: Seyed Abolhasan Naeini, Saeideh Mohammadi

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Rapid urban development leads to the construction of urban tunnels for transport. Passage of tunnels under the surface structures and utilities prompted the changes in the site conditions and hence alteration of the dynamic response of surface structures. Therefore, in this study, the effect of the interaction of tunnel-superstructure on the site response is investigated numerically. For this purpose, Fast Lagrangian Analysis of Continua (FLAC 2D) is used, and stratification and properties of soil layers are selected based on the line No 7 of Tehran subway. The superstructure is modeled both as an equivalent surcharge and the actual structure, and the results are compared. A comparison of the results shows that consideration of structure geometry is necessary for dynamic analysis and it leads to the changes in displacements and accelerations. Consequently, the geometry of the superstructure should be modeled completely instead of the application of an equivalent load. The effect of tunnel diameter and depth on the settlement of superstructures is also studied. Results show that when the tunnel depth and diameter grow, the settlements increase considerably.

Keywords: tunnel, FLAC2D, settlement, dynamic analysis

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Authors: Tauhidur Rahman, Gitartha Kalita

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In this study a four span box girder bridge is considered and effect of the rotational and translational earthquake ground motion have been thoroughly investigated. This study is motivated by the fact that in many countries the translational and rotational components of earthquake ground motion, especially rocking, is not adequately considered in analysing the overall response of the structures subjected to earthquake ground excitations. Much consideration is given to only the horizontal components of the earthquake ground motion during the response analysis of structures. In the present research work, P waves, SV waves and Rayleigh wave excitations are considered for different angle of incidence. In the present paper, the four span bridge is model considering the effects of vertical and rocking components of P, SV and Rayleigh wave excitations. Ground responses namely displacement, velocity and acceleration of the substructures of the bridge have been considered for rotational and translational effects in addition to the horizontal ground motion due to earthquake and wind.

Keywords: ground motion, response, rotational effects, translational effects

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Authors: Ewa Brychcy, Natalia Ulbin-Figlewicz, Dominika Kulig, Żaneta Król, Andrzej Jarmoluk

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Acidic electrolyzed water (AEW) is an alternative with environmentally friendly broad spectrum microbial decontamination. It is produced by membrane electrolysis of a dilute NaCl solution in water ionizers. The aim of the study was to evaluate the effectiveness of low-concentrated AEW in reducing selected foodborne pathogens and to examine its bactericidal effect on cellular structures of Escherichia coli. E. coli and S. aureus cells were undetectable after 10 minutes of contact with electrolyzed salt solutions. Non-electrolyzed solutions did not inhibit the growth of bacteria. AE water was found to destroy the cellular structures of the E. coli. The use of more concentrated salt solutions and prolonged electrolysis time from 5 to 10 minutes resulted in a greater changes of rods shape as compared to the control and non-electrolyzed NaCl solutions. This research showed that low-concentrated acid electrolyzed water is an effective method to significantly reduce pathogenic microorganisms and indicated its potential application for decontamination of meat.

Keywords: acidic electrolyzed water, foodborne pathogens, meat decontamination, membrane electrolysis

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Authors: Subramaniam Chandran, A. Geetha

Abstract:

This paper addresses three issues: how to prepare the instructional design for imparting English language skill from inter-disciplinary self-learning material; how the disadvantaged students are benefited from such kind of language skill imparted through m-learning; and how do m-learners perform better than the other learners. This paper examines these issues through an experimental study conducted among the distance learners enrolled in a preparatory program for bachelor’s degree. This program is designed for the disadvantaged learners especially for the school drop-outs to qualify to pursue graduate program through distant education. It also explains how mobile learning helps them to enhance their capacity in learning despite their rural background and other disadvantages. In India, nearly half of the students enrolled in schools do not complete their study. The pursuance of higher education is very low when compared with developed countries. This study finds a significant increase in their learning capacity and mobile learning seems to be a viable alternative where the conventional system could not reach the disadvantaged learners. Improving the English language skill is one of the reasons for such kind of performance. Exercises framed from the relevant self-learning material for enhancing English language skill not only improves language skill but also widens the subject-knowledge. This paper explains these issues out of the study conducted among the disadvantaged learners.

Keywords: English language skill, disadvantaged learners, distance education, m-learning

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Authors: Mehdi Habibagahi, Shami Nejadi, Ata Aminfar

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A significant degradation factor that impacts the durability of concrete structures is the alkali-silica reaction. Engineers are frequently charged with the challenges of conducting a thorough safety assessment of concrete structures that have been impacted by ASR. The alkali-silica reaction has a major influence on the structural capacities of structures. In most cases, the reduction in compressive strength, tensile strength, and modulus of elasticity is expressed as a function of free expansion and crack widths. Predicting the effect of ASR on flexural strength is also relevant. In this paper, a nonlinear three-dimensional (3D) finite-element model was proposed to describe the flexural strength degradation induced byASR.Initial strains, initial stresses, initial cracks, and deterioration of material characteristics were all considered ASR factors in this model. The effects of ASR on structural performance were evaluated by focusing on initial flexural stiffness, force–deformation curve, and load-carrying capacity. Degradation of concrete mechanical properties was correlated with ASR growth using material test data conducted at Tech Lab, UTS, and implemented into the FEM for various expansions. The finite element study revealed a better understanding of the ASR-affected RC beam's failure mechanism and capacity reduction as a function of ASR expansion. Furthermore, in this study, decreasing of the residual mechanical properties due to ASRisreviewed, using as input data for the FEM model. Finally, analysis techniques and a comparison of the analysis and the experiment results are discussed. Verification is also provided through analyses of reinforced concrete beams with behavior governed by either flexural or shear mechanisms.

Keywords: alkali-silica reaction, analysis, assessment, finite element, nonlinear analysis, reinforced concrete

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Authors: Neda Nabid

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Friction-based supplemental devices have been extensively used for seismic protection and strengthening of structures, however, the conventional use of these dampers may not necessarily lead to an efficient structural performance. Conventionally designed friction dampers follow a uniform height-wise distribution pattern of slip load values for more practical simplicity. This can lead to localizing structural damage in certain story levels, while the other stories accommodate a negligible amount of relative displacement demand. A practical performance-based optimization methodology is developed to tackle with structural damage localization of RC frame buildings with friction energy dissipation devices under severe earthquakes. The proposed methodology is based on the concept of uniform damage distribution theory. According to this theory, the slip load values of the friction dampers redistribute and shift from stories with lower relative displacement demand to the stories with higher inter-story drifts to narrow down the discrepancy between the structural damage levels in different stories. In this study, the efficacy of the proposed design methodology is evaluated through the seismic performance of five different low to high-rise RC frames equipped with friction wall dampers under six real spectrum-compatible design earthquakes. The results indicate that compared to the conventional design, using the suggested methodology to design friction wall systems can lead to, by average, up to 40% reduction of maximum inter-story drift; and incredibly more uniform height-wise distribution of relative displacement demands under the design earthquakes.

Keywords: friction damper, nonlinear dynamic analysis, RC structures, seismic performance, structural damage

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Authors: M. Saadi, S. E. H. Abaidia, M. Y. Mokeddem.

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We present the results of a systematic and comparative study of the bulk, the structural properties, and phonon calculations of aluminum alloys using several exchange–correlations functional theory (DFT) with different plane-wave basis pseudo potential techniques. Density functional theory implemented by the Vienna Ab Initio Simulation Package (VASP) technique is applied to calculate the bulk and the structural properties of several structures. The calculations were performed for within several exchange–correlation functional and pseudo pententials available in this code (local density approximation (LDA), generalized gradient approximation (GGA), projector augmented wave (PAW)). The lattice dynamic code “PHON” developed by Dario Alfè was used to calculate some thermodynamics properties and phonon dispersion relation frequency distribution of Aluminium alloys using the VASP LDA PAW and GGA PAW results. The bulk and structural properties of the calculated structures were compared to different experimental and calculated works.

Keywords: DFT, exchange-correlation functional, LDA, GGA, pseudopotential, PAW, VASP, PHON, phonon dispersion

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Authors: Cameron Brown, Jessica Vanburen, Scott Hunt

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This study analyzed 411 international newspaper stories pertaining to gambling-related crimes from January 2013 to December 2014. These stories included accounts of crimes committed to fund gambling or pay gambling debts or that occurred at gambling establishments. Our analysis pays particular attention to those crimes that were imputed to be committed by “problem” or “addictive” gamblers, who commit crimes to fund gambling or pay gambling debts. Previous research on problem/addictive gambling has focused on its etiology or prevalence rates and has not attended to the media portrayals of this behavior and its association with crime. Using frame analysis concepts, the data demonstrate that the newspaper stories typically frame the events as “crimes” and not the result of illness or addiction. The “evidence” of motive that could have indicated psychological problems or additions were rather framed as “criminal motive.” This framing practice advances an identity of a “problem/addictive gambler” as a deviant criminal perpetrator and not a victim of addiction. The paper concludes with a discussion of how these findings can be used to advance research on social portrayals of problem/addictive gamblers. Specifically, we consider how these media frames impede an understanding of problem/addictive gambling as a public health problem.

Keywords: problem gambling, addictive gambling, identity resonace, frame analysis

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Authors: Seung-Ho Choi, Jae Yuel Oh, Chi Sung Lim, Ho Seong Jung, Kang Su Kim

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In recent years, various strengthening methods for buildings have been developed, but most of them require quite a long construction period during which the building users need to be patient on uncomfortable working environments including various lousy noises or even evacuation of the buildings. In this study, externally anchored precast wall-panel method (EPCW) for strengthening non-seismic reinforced concrete (RC) structures has been proposed, which is occupant-friendly technique because the strengthening walls are manufactured at factory and can be tightened to the members very quickly at the site. In order to investigate the structural performance of the specimens strengthened by the EPCW method, a total of four specimens were fabricated, and tested under axial and reversed cyclic lateral loads. The test results showed that the lateral resistances of the specimens strengthened by the EPCW method were greatly enhanced in both positive and negative directions, compared to the RC specimen having non-seismic details.

Keywords: precast wall, seismic strengthening, reinforced concrete, externally-anchored

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Authors: Wooseok Song, Sunjung Park, Jongkwon Lee, Jaye Koo

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The objective of this paper is to observe the effects of injection conditions on flame structures in gas-centered swirl coaxial injector. Gaseous oxygen and liquid kerosene were used as propellants. For different injection conditions, two types of injector, which only differ in the diameter of the tangential inlet, were used in this study. In addition, oxidizer injection pressure was varied to control the combustion chamber pressure in different types of injector. In order to analyze the combustion instability intensity, the dynamic pressure was measured in both the combustion chamber and propellants lines. With the increase in differential pressure between the propellant injection pressure and the combustion chamber pressure, the combustion instability intensity increased. In addition, the flame structure was recorded using a high-speed camera to detect CH* chemiluminescence intensity. With the change in the injection conditions in the gas-centered swirl coaxial injector, the flame structure changed.

Keywords: liquid rocket engine, flame structure, combustion instability, dynamic pressure

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Authors: Benhammadi Hocine, Chaffai Hicham

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Urban development is often dependent on adequate land for expansion, except that sometimes these areas have vulnerability. This is the case of karst regions characterized by carbonate geological formations marked by the presence of cavities and cracks. The impact of climate variability in Cheria area marked by a growing shortage of rainfall, the impact resulted in the development of the vulnerability of these structures. This vulnerability has led to the appearance of collapse phenomena as well in both agricultural and urban areas. Two phenomena have emerged to explain the collapses, the first is assigned a filling process in the cavities, and the second is due to a weakening of the resistance that collapses limestone slab shear phenomenon. In urban areas, the weight of the buildings has increased the load on the limestone slab and accelerated the collapse. The analysis of the environmental process is in the context of our modest work, after which we indicate the appropriate methods for management policy of urban expansion. This management more preventive (upstream), much less expensive than remedial solutions (downstream) needed after the event and sometimes ineffective.

Keywords: Cheria, urban, climate variability, vulnerability karst collapse, extension, management

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Authors: Shai Gabay

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The tunnel effect describes the phenomenon where a moving object seems to persist even when temporarily hidden from view. Numerous studies indicate that humans, infants, and nonhuman primates possess object persistence, relying on spatiotemporal cues to track objects that are dynamically occluded. While this ability is associated with neural activity in the cerebral neocortex of humans and mammals, the role of subcortical mechanisms remains ambiguous. In our current investigation, we explore the functional contribution of monocular aspects of the visual system, predominantly subcortical, to the representation of occluded objects. This is achieved by manipulating whether the reappearance of an object occurs in the same or different eye from its disappearance. Additionally, we employ Archerfish, renowned for their precision in dislodging insect prey with water jets, as a phylogenetic model to probe the evolutionary origins of the tunnel effect. Our findings reveal the active involvement of subcortical structures in the mental representation of occluded objects, a process evident even in species that do not possess cortical tissue.

Keywords: archerfish, tunnel effect, mental representations, monocular channels, subcortical structures

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Authors: Hadach Fatiha, Algouti Ahmed, Algouti Abdellah, Jdaba Naji, Es-Sarrar Othman, Mourabit Zahra

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This paper investigates the structure and evolution of diapirism in the Ait Ourir basin, located in the High Atlas of Marrakesh, using structural and sedimentological fieldwork integrated with field mapping. A tectonic-sedimentological study of the Mesozoic cover of the Ait Ourir basin area revealed that these units were subjected to important saccadic halokinetic activity, reflected by anticline structures associated with regional faults that created several synclinal mini-basins. However, the lack of seismic coverage in the study area makes the proposed interpretation based on extrapolations of information observed on the surface. In this work, we suggest that faults and salt activity led to the formation of different structures within the studied area. The growth of the Triassic evaporites at different stages during the Mesozoic is reflected by progressive and local unconformities, recorded as having different ages. These structures created high diapiric zones with reduced sedimentation, showing abrupt lateral thickness variations in several places where this activity was occurring; this is clearly defined within the Wanina and Jbel Sour’s mini-basins, where the Senonian was observed to rest at an angular unconformity over the entire sedimentary cover encompassing the time period from the Liassic to the Turonian. The diapirism associated with the major faults, especially encountered between the basins, is often accompanied by late Triassic volcanic material. This diapir-fault relationship resulted in shallow and often depocentric zones in a pull-apart system within a distensive context.

Keywords: diapir, evaporites, faults, pull-apart, Mesozoic cover, Ait Ourir, western High Atlas, Morocco

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Authors: Ekin Ozer

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Assessment of structural reliability is essential for efficient use of civil infrastructure which is subjected hazardous events. Dynamic analysis of finite element models is a commonly used tool to simulate structural behavior and estimate its performance accordingly. However, theoretical models purely based on preliminary assumptions and design drawings may deviate from the actual behavior of the structure. This study proposes up-to-date reliability estimation procedures which engages actual bridge vibration data modifying finite element models for finite element model updating and performing reliability estimation, accordingly. The proposed method utilizes vibration response measurements of bridge structures to identify modal parameters, then uses these parameters to calibrate finite element models which are originally based on design drawings. The proposed method does not only show that reliability estimation based on updated models differs from the original models, but also infer that non-updated models may overestimate the structural capacity.

Keywords: earthquake engineering, engineering vibrations, reliability estimation, structural health monitoring

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Authors: H. Abbasi, K. Sennah

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A Structural Insulated Panel (SIP) is a structural element contains of foam insulation core sandwiched between two oriented-strand boards (OSB), plywood boards, steel sheets or fibre cement boards. Superior insulation, exceptional strength and fast insulation are the specifications of a SIP-based structure. There are also many other benefits such as less total construction costs, speed of construction, less expensive HVAC equipment required, favourable energy-efficient mortgages comparing to wood-framed houses. This paper presents the experimental analysis on selected foam-timber SIPs to study their structural behaviour when used as walls in residential construction under lateral loading. The experimental program has also taken several stud panels in order to compare the performance of SIP with conventional wood-frame system. The results of lateral tests performed in this study established a database that can be used further to develop design tables of SIP wall subjected to lateral loading caused by wind or earthquake. A design table for walls subjected to lateral loading was developed. Experimental results proved that the tested SIPs are ‘as good as’ the conventional wood-frame system.

Keywords: structural insulated panel, experimental study, lateral load, design tables

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Authors: Abdurrahim Bolukbasi, Hassan Athari, Dogan Ciloglu

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The modeling lung respiratory system which has complex anatomy and biophysics presents several challenges including tissue-driven flow patterns and wall motion. Also, the lung pulmonary system because of that they stretch and recoil with each breath, has not static walls and structures. The direct relationship between air flow and tissue motion in the lung structures naturally prefers an FSI simulation technique. Therefore, in order to toward the realistic simulation of pulmonary breathing mechanics the development of a coupled FSI computational model is an important step. A simple but physiologically-relevant three dimensional deep long geometry is designed and fluid-structure interaction (FSI) coupling technique is utilized for simulating the deformation of the lung parenchyma tissue which produces airflow fields. The real understanding of respiratory tissue system as a complex phenomenon have been investigated with respect to respiratory patterns, fluid dynamics and tissue visco-elasticity and tidal breathing period.

Keywords: lung deformation and mechanics; Tissue mechanics; Viscoelasticity; Fluid-structure interactions; ANSYS

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Authors: Gokhan Dok, Hakan Ozturk, Aydin Demir

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The behavior of reinforced concrete (RC) members is quite important in RC structures. When evaluating the performance of structures, the nonlinear properties are defined according to the cross sectional behavior of RC members. To be able to determine the behavior of RC members, its cross sectional behavior should be known well. The moment-curvature (MC) relationship is used to represent cross sectional behavior. The MC relationship of RC cross section can be best determined both experimentally and numerically. But, experimental study on RC members is very difficult. The aim of the study is to obtain the MC relationship of RC shear walls. Additionally, it is aimed to determine the parameters which affect MC relationship. While obtaining MC relationship of RC members, XTRACT which can represent robustly the MC relationship is used. Concrete quality, longitudinal and transverse reinforcing ratios, are selected as parameters which affect MC relationship. As a result of the study, curvature ductility and effective flexural stiffness are determined using this parameter. Effective flexural stiffness is compared with the values defined in design codes.

Keywords: moment-curvature, reinforced concrete, shear wall, numerical

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Authors: M.Rüştü Karaman, İsmail İşeri, Kadir Saltalı, A.Reşit Brohi, Ayhan Horuz, Mümin Dizman

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Considerable relations has recently been given to the environmental hazardous caused by agricultural chemicals such as excess fertilizers. In this study, a neural network approach was investigated in the prediction of potential nitrate pollution across different land-use patterns by using a feedforward multilayered computer model of artificial neural network (ANN) with proper training. Periodical concentrations of some anions, especially nitrate (NO3-), and cations were also detected in drainage waters collected from the drain pipes placed in irrigated tomato field, unirrigated wheat field, fallow and pasture lands. The soil samples were collected from the irrigated tomato field and unirrigated wheat field on a grid system with 20 m x 20 m intervals. Site specific nitrate concentrations in the soil samples were measured for ANN based simulation of nitrate leaching potential from the land profiles. In the application of ANN model, a multi layered feedforward was evaluated, and data sets regarding with training, validation and testing containing the measured soil nitrate values were estimated based on spatial variability. As a result of the testing values, while the optimal structures of 2-15-1 was obtained (R2= 0.96, P < 0.01) for unirrigated field, the optimal structures of 2-10-1 was obtained (R2= 0.96, P < 0.01) for irrigated field. The results showed that the ANN model could be successfully used in prediction of the potential leaching levels of nitrate, based on different land use patterns. However, for the most suitable results, the model should be calibrated by training according to different NN structures depending on site specific soil parameters and varied agricultural managements.

Keywords: artificial intelligence, ANN, drainage water, nitrate pollution

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Authors: Seyed Abolhasan Naeini, Mohammad Hosseinzade

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Settlement and bearing capacity of a piled raft are the two important issues for the foundations of the structures built on coastal areas from the geotechnical engineering point of view. Strip piled raft as a load carrying system could be used to reduce the possible extensive consolidation settlements and improve bearing capacity of structures in soft ground. The aim of this research was to evaluate the efficiency of strip piled raft embedded in soft clay. The efficiency of bearing capacity of strip piled raft foundation is evaluated numerically in two cases: in first case, the cap is placed directly on the ground surface and in the second, the cap is placed above the ground. Regarding to the fact that the geotechnical parameters of the soft clay are considered at low level, low bearing capacity is expected. The length, diameter and axe-to-axe distance of piles are the parameters which varied in this research to find out how they affect the bearing capacity. Results indicate that increasing the length and the diameter of the piles increase the bearing capacity. The complementary results will be presented in the final version of the paper.

Keywords: soft clay, strip piled raft, bearing capacity, settlement

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Authors: Myoung-Jin Lee, Sung-Jin Lee, Young-Kon Park, Jin-Wook Kim, Bo-Kyoung Kim, Song-Hun Chong, Sun-Il Kim

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Currently, sinkholes may occur due to natural or unknown causes. When the sinkhole is an instantaneous phenomenon, most accidents occur because of significant damage. Thus, methods of monitoring are being actively researched, such that the impact of the accident can be mitigated. A sinkhole can severely affect and wreak havoc in community-based facilities such as a city railway construction. Therefore, the development of a laser / scanning system and an image-based tunnel is one method of pre-monitoring that it stops the accidents. The laser scanning is being used but this has shortcomings as it involves the development of expensive equipment. A laser / videobased scanning tunnel is being developed at Korea Railroad Research Institute. This is designed to automatically operate the railway. The purpose of the scanning is to obtain an image of the city such as of railway structures (stations, tunnel). At the railway structures, it has developed 3D laser scanning that can find a micro-crack can not be distinguished by the eye. An additional aim is to develop technology to monitor the status of the railway structure without the need for expensive post-processing of 3D laser scanning equipment, by developing corresponding software.

Keywords: 3D laser scanning, sinkhole, tunnel, city railway construction

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Authors: Subramaniam Chandran, A. Geetha

Abstract:

This paper addresses three issues: how to prepare instructional design for imparting English language skill from inter-disciplinary self-learning material; how the disadvantaged students are benefited from such kind of language skill imparted through m-learning; and how do the m-learners perform better than the other learners. This paper examines these issues through an experimental study conducted among the distance learners enrolled in preparatory program for bachelor’s degree. This program is designed for the disadvantage learners especially for the school drop-outs to qualify to pursue graduate program through distant education. It also explains how mobile learning helps them to enhance their capacity in learning despite their rural background and other disadvantages. In India nearly half of the students enrolled in schools do not complete their study. The pursuance of higher education is very low when compared with developed countries. This study finds a significant increase in their learning capacity and mobile learning seems to be a viable alternative where conventional system could not reach the disadvantaged learners. Improving the English language skill is one of the reasons for such kind of performance. Exercises framed from the relevant self-learning material for enhancing English language skill not only improves language skill but also widens the subject-knowledge. This paper explains these issues out of the study conducted among the disadvantaged learners.

Keywords: English language skill, disadvantaged learners, distance education, m-learning

Procedia PDF Downloads 644

Authors: Radhwane Boudjelthia

Abstract:

The most recent earthquakes occurred in the world have killed thousands of people and severe damage. For all the actors involved in the building process, the earthquake is the litmus test for construction. The goal we set ourselves is to contribute to the implementation of a thoughtful approach to the seismic protection of structures. For many engineers, the most conventional approach to protection works (buildings and bridges) the effects of earthquakes is to increase rigidity. This approach is not always effective, especially when there is a context that favors the phenomenon of resonance and amplification of seismic forces. Therefore, the field of earthquake engineering has made significant inroads, among others catalyzed by the development of computational techniques in computer form and the use of powerful test facilities. This has led to the emergence of several innovative technologies, such as the introduction of special devices insulation between infrastructure and superstructure. This approach, commonly known as "seismic isolation," to absorb the significant efforts without the structure is damaged and thus ensuring the protection of lives and property. In addition, the restraints to the construction by the ground shaking are located mainly at the supports. With these moves, the natural period of construction is increasing, and seismic loads are reduced. Thus, there is an attenuation of the seismic movement. Likewise, the insulation of the base mechanism may be used in combination with earthquake dampers in order to control the deformation of the insulation system and the absolute displacement of the superstructure located above the isolation interface. On the other hand, only can use these earthquake dampers to reduce the oscillation amplitudes and thus reduce seismic loads. The use of damping devices represents an effective solution for the rehabilitation of existing structures. Given all these acceleration reducing means considered passive, much research has been conducted for several years to develop an active control system of the response of buildings to earthquakes.

Keywords: earthquake, building, seismic forces, displacement, resonance, response.

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Authors: Rajkumar Ghosh

Abstract:

Out-of-sequence thrusts (OOST) are reported at different geographic locations with various local names along Siwalik Himalaya (SH), Lesser Himalaya (LH), Higher Himalaya (HH) from Bhutan, India, Nepal, and Pakistan Himalayan range. Most of OOSTs have been identified within the upper LH, and the lower HH based on geochronological age jump across. These thrusts activated from Late Miocene to recent. The Chaura Thrust (CT) was deciphered from age jump of Apatite Fission Track (AFT) and considered as blind thrust base on variable exhumation rates in Chaura region, Satluj river valley, Himachal Pradesh. CT is located north of Jhakri Thrust (JhT) and is also differently identified as Sarahan thrust (ST). Structural documentation from the rocks near the OOST in Chaura was not so far done. Detail structural study of the Jeori Group of rocks was carried out in this study to understand the manifestation of the Chaura thrust and associated structures in meso- to micro-scale. Box fold, scar fold, kink fold, crenulation cleavages, and boudins are developed in the Chaura region. These structures usually do not indicate shear sense. When studied under an optical microscope, the Chaura samples reveal that the mica fish are usually lenticular with aspect ratio (R) varying from 6–11 and inclination angle (α) from 15–40°. According to ‘R’ and ‘α’, elongated sigmoid shaped mica fish and parallelogram shaped mica fish were also documented. Asymmetric mica fish demonstrate top-to-S/SW ductile shear, which is similar as that of Chaura thrust. Grain boundary migration (GBM) structures in quartzo-feldspathic grains from Jeori Group of rocks indicate deformation temperature ranging from 400 to 650°C. This can indicate that the OOST at Chaura, i.e., the Chaura Thrust, underwent thrusting in the ductile regime.

Keywords: out-of-sequence thrust, chaura thrust, sarahan thrust, jakhri thrust, higher himalaya, s/c- fabric

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Authors: Vithul Kalki

Abstract:

The mainstream political economy failed to explain the nature and causes of systemic failures and thus to compare and comprehend how contemporary capitalist systems work. An alternative research framework of Critical Macro-Finance (CMF) is an attempt to collaborate political theory with post-Keynesian economics with an objective to find answers to unresolved questions that emerged since the international financial crisis and repeated failures of capital systems. This unorthodox approach brings out four main propositions, namely : (a) that the adoption of American financial practices has anchored financial globalization in market-based finance; (b) that global finance is a set of interconnected, hierarchical balance sheets, increasingly subject to time-critical liquidity; (c) that credit creation in market-based finance involves new forms of money; and (d) that market-based finance structurally requires a de-risking state capable both of protecting systemic liabilities and creating new investment opportunities. The ongoing discussion of CMF literature is yet to be tested or even fully framed. This qualitative paper will critically examine the CMF framework and will engage in discussions aiming to connect the CMF with theories of capitalism in a wider context to bring a holistic approach for analyzing contemporary financial capitalism.

Keywords: critical macro-finance, capitalism, financial system, comparative political economy

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Authors: S. K. Hashemi, M. A. Bradford, H. R. Valipour

Abstract:

The Recent collapse of bridges has raised the awareness about safety and robustness of bridges subjected to extreme loading scenarios such as intentional/unintentional blast loads. The air blast generated by the explosion of bombs or fuel tankers leads to high-magnitude short-duration loading scenarios that can cause severe structural damage and loss of critical structural members. Hence, more attentions need to put towards bridge structures to develop guidelines to increase the resistance of such structures against the probable blast. Recent advancements in numerical methods have brought about the viable and cost effective facilities to simulate complicated blast scenarios and subsequently provide useful reference for safeguarding design of critical infrastructures. In the previous studies common bridge responses to blast load, the traffic load is sometimes not included in the analysis. Including traffic load will increase the axial compression in bridge piers especially when the axial load is relatively small. Traffic load also can reduce the uplift of girders and deck when the bridge experiences under deck explosion. For more complicated structures like cable-stayed or suspension bridges, however, the effect of traffic loads can be completely different. The tension in the cables increase and progressive collapse is likely to happen while traffic loads exist. Accordingly, this study is an attempt to simulate the effect of traffic load cases on the maximum local and global response of an entire cable-stayed bridge subjected to blast loadings using LS-DYNA explicit finite element code. The blast loads ranged from small to large explosion placed at different positions above the deck. Furthermore, the variation of the traffic load factor in the load combination and its effect on the dynamic response of the bridge under blast load is investigated.

Keywords: blast, cable-stayed bridge, LS-DYNA, numerical, traffic load

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