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Home>Products>Journal and Reviews>I.RE.C.E.>Latest issue
International Review of Civil Engineering - November 2011 (Vol. 2 N. 6) - Papers
International Review of Civil Engineering - Papers
Abstract - This
paper is aimed to explain a new methodology for evaluating the behaviour
of sandy soil under dynamic loadings. In order to do so, only standard
soil mechanics laboratory equipment has been used. Currently, the
liquefaction potential is determined in the laboratory by means of
undrained and drained dynamic triaxial, resonant column or shaking table
tests. However, these tests are far from being of generalized use in
most soil mechanics laboratories. The equipment employed herein has been
the conventional direct shear box, in which the cyclic loading is
manually applied to different samples of quartzitic sand subjected to
various vertical loading conditions. By correlating the stress
distributions in the direct shear box and the simple shear apparatus, a
recently proposed liquefaction model has been calibrated, and the sand
liquefaction potential has been estimated.
Keywords: Densification, Cyclic Shear Tests, Liquefaction Potential.
Abstract - Prediction and control of the excessive settlements are very important in the design of different structures. In recent decades, many ways of prediction of settlement have been developed by researchers. Using soil models via numerical methods for prediction of soil behavior is one of the newest of them. In this regard the critical state models have been used widely for this purpose.The Modified Cam-clay model is an elastic plastic strain hardening model that is based on Critical state theory. This model is used in geotechnical engineering practice. Nevertheless, due to some reasons using of this modelis in doubt for practical issues. In this paper, a pair of circular and rectangular footings has been modeled via finite-element method and Modified Cam-clay model in a case study. In the next step, the predicted and monitored settlements of these footings were compared. Finally, relatively good and conservative performance of Modified Cam-clay theory is shown in practice, as the main aim of this paper. Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Modified Cam-Clay Theory, Finite Element Method, Settlement.
Abstract - In this
study, the theoretical behavior of curved prestressed concrete beams
have been investigated by using of three dimensional finite element
method, in order to understand the behavior of this beam under
incremental loads up to failure and also under long-term time
conditions. Therefore, the analytical study have been done by parts:
First part deals with short-term analysis, and other part deals with
long-term analysis. This analysis is done by depending on package
programs (ANSYS+CivilFEM V12.0 version 2009). Willam and Warnke models
have used to represent the nonlinear behavior for concrete. The curved
prestressed concrete beam represents by three dimensional model include
of Isoparametric 8-Node Brick Element known as SOLID65 which is used in
short-term analysis, while the Element known as SOLID185 have been used
in long-term analysis. Due to the time-dependent effect on ultimate load
value for concrete structures, both of the creep and the shrinkage
effects on properties and behavior for concrete have been taken into
consideration using finite elements technology dependence on
recommendation committee of American Concrete Institute (ACI 209). Also,
the effective modulus approaches used in the representation of creep
effect. Also, all the prestressed loss for prestress concrete members
have been included.
Keywords: Curved Beam, ANSYS+CivilFEM, SOLID65, Creep, Long-Term, Shrinkage, Prestressed Losses.
Abstract - Each
concrete component has a very important role on the tribological
behavior in the vicinity of wall surface. The objective of this paper is
to understand the influence of the paste volume on the mechanisms
intervening at the concrete/formwork. Two concrete with 28 and 34% of
paste were formulated in order to study the influence of fines content
at the concrete/wall interface. Friction tests were carried out using an
apparatus which can reproduce the same conditions of jobsites. Then,
three types of mixtures fine elements and the aggregates forming the
granular skeleton were prepared to study the effect of water content and
aggregates on the interface behavior of fresh concrete. The results show
that the friction is governed by the cement grains and its water
content. Hypotheses were proposed to explain the different mechanisms
occurring at the interface.
Keywords: Cement Grains, Tribology, Friction, Interface, Fresh Concrete, Formwork.
Abstract -
Plate anchors are being increasingly used as a foundation system to
provide uplift resistance for several types of structures constructed
both on land and offshore sites. Accurate estimation of the ultimate
uplift capacity is necessary in the design to ensure the safety and
stability of the supported structures. A parametric study has been
carried out with finite element modeling using PLAXIS to estimate the
ultimate uplift capacity of horizontal anchor plates embedded in
cohesionless soils by varying soil relative density and embedment ratio.
The results have been compared with those obtained from various methods
and approaches which are based on theoretical, computational, physical
and experimental studies.
Keywords: Plate Anchors, Uplift Capacity, Finite Element Analysis, Parametric Study.
Abstract -
Attikes Diadromes S.A (the company ensuring the “Maintenance – Operation
and Exploitation of the motorway Elefsina – Stavros – Spata Airport &
West Peripheral Ymittos Avenue”), in cooperation with the University of
Thessaly - Faculty of Civil Engineering (Laboratory of Environmental
Transportation Acoustics-LTEA) has executed during 2010 (an extended
environmental monitoring & research program [1] in, selected toll booths
of “Attiki Odos” network (Athens Ring Road) & also to selected
maintenance machinery equipment, aiming at the evaluation of
environmental noise, body vibration & air pollution generated from the
road operation aiming at the evaluation of the relevant impact at the
employees exposed during working periods. This article presents and
evaluates the relevant full typical week (24/7) monitoring measurements
in the selected booths in comparison with the existing criteria &
limits.
Keywords: Air Pollution, Attiki Odos Motorway, Body Vibration, Environmental Noise, Toll Booths.
Abstract -
Driver’s fatigue has received considerable attention as a road safety
issue, worldwide, for all kind of vehicles(light, heavy etc)and all kind
of drivers(ordinary, professional etc). The deteriorating driver
performance associated with driver fatigue presents a serious safety
risk. In the present paper, the relationship between driving performance
and fatigue is examined using an innovative, specially instrumented,
vehicle. According to a pilot study that was conducted, the
investigation whether the driving behaviour, as it can be interpreted
through speeding and accelerating profiles analysis, is directly related
to drive’s fatigue. A deep analysis of the variation of the trajectories
followed in different driver’s fatigue levels combined with the relevant
speeding and accelerating profiles is very revealing, in order to assess
the severe impact of the tired driver’s behaviour and attitude.
Keywords: Driver’s Behaviour, Fatigue, Speed, Safety, Accidents.
Abstract -
Finite element method is used to determine the ultimate bearing capacity
of Circular Footing resting on geogrid reinforced sand. The effect of
each of the depth ratio of the topmost layer of geogrid (u/D), the
vertical distance ratio between consecutive layers (h/D), number of
geogrid layers (N), and the effective depth ratio of reinforcement (d/
D) on the bearing capacity were studied, where (D) is the footing
diameter. In addition, for all these parameters, depth of embedment
ratio of footing (D / Df) and the angle of internal friction
( Φ) on the ultimate bearing capacity were studied as well. In general,
the results showed that by increasing the number of reinforcement layers
(N), the bearing capacity increased. The optimum value of reinforcement
layers was (N=3-5) .The optimum depth ratio of the topmost layer geogrid
was between (0.25D-0.3D-0.35D) depending on the angle of internal
friction (30˚,35˚,40˚)respectively. The optimum vertical distance ratio
between consecutive layers was between
(0.325D-0.35D),(0.225D-0.25D)and(0.3D-0.375D). As a result, the optimum
effective depth ratio of reinforcement was between (0.95D-1.55D),
(0.8D-1.2D) and (0.95D-1.1D)depending on the angle of internal friction
(30˚,35˚,40˚)respectively. Also, the depth of embedment ratio of footing
was (0D,0.25D,0.5D) respectively.
Keywords: Bearing Capacity, Finite Element, Geogrid, Reinforced Sand, Circular Footing.
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