Abstract: Over the early years of the 21st century, cities
throughout the Middle East, particularly in the Gulf region have
expanded more rapidly than ever before. Given the presence of a
large volume of high-rise buildings allover the region, the local
authority aims to set a new standard for sustainable development;
with an integrated approach to maintain a balance between economy,
quality, environmental protection and safety of life. In the very near
future, as mandatory requirements, sustainability will be the criteria
that should be included in all building projects. It is well known in
the building sustainability topics that structural design engineers do
not have a key role in this matter. In addition, the LEED (Leadership
in Energy and Environmental Design) has looked almost exclusively
on the environmental components and materials specifications. The
objective of this paper is to focus and establish groundwork for
sustainability techniques and applications related to the RC high-rise
buildings design, from the structural point of view. A set of
recommendations related to local conditions, structural modeling and
analysis is given, and some helpful suggestions for structural design
team work are addressed. This paper attempts to help structural
engineers in identifying the building sustainability design, in order to
meet local needs and achieve alternative solutions at an early stage of
project design.
Abstract: Time-Cost Optimization "TCO" is one of the greatest challenges in construction project planning and control, since the optimization of either time or cost, would usually be at the expense of the other. Since there is a hidden trade-off relationship between project and cost, it might be difficult to predict whether the total cost would increase or decrease as a result of the schedule compression. Recently third dimension in trade-off analysis is taken into consideration that is quality of the projects. Few of the existing algorithms are applied in a case of construction project with threedimensional trade-off analysis, Time-Cost-Quality relationships. The objective of this paper is to presents the development of a practical software system; that named Automatic Multi-objective Typical Construction Resource Optimization System "AMTCROS". This system incorporates the basic concepts of Line Of Balance "LOB" and Critical Path Method "CPM" in a multi-objective Genetic Algorithms "GAs" model. The main objective of this system is to provide a practical support for typical construction planners who need to optimize resource utilization in order to minimize project cost and duration while maximizing its quality simultaneously. The application of these research developments in planning the typical construction projects holds a strong promise to: 1) Increase the efficiency of resource use in typical construction projects; 2) Reduce construction duration period; 3) Minimize construction cost (direct cost plus indirect cost); and 4) Improve the quality of newly construction projects. A general description of the proposed software for the Time-Cost-Quality Trade-Off "TCQTO" is presented. The main inputs and outputs of the proposed software are outlined. The main subroutines and the inference engine of this software are detailed. The complexity analysis of the software is discussed. In addition, the verification, and complexity of the proposed software are proved and tested using a real case study.
Abstract: This paper analysis performance of disbursement
procedure of public works project in Thailand. The results of
research were summarised based on contracts, submitted invoice,
inspection dated, copies of disbursement dated between client and
their main contractor and interviewed with persons involved in
central and local government projects during 1994-2008 in Thailand.
The data collection was to investigate the disbursement procedure
related to performance in disbursement during construction period
(Planned duration of contract against Actual execution date in each
month). A graphical presentation of a duration analysis of the
projects illustrated significant disbursement formation in each
project. It was established that the shortage of staff, the financial
stability of clients, bureaucratic, method of disbursement and
economics situation has play major role on performance of
disbursement to their main contractors.
Abstract: Adopting the measured constitutive relationship of
stress-strain of river ice, the finite element analysis model of
percussive force of river ice and pier is established, by the explicit
dynamical analysis software package LS-DYNA. Effects of element
types, contact method and arithmetic of ice and pier, coupled modes
between different elements, mesh density of pier, and ice sheet in
contact area on the collision force are studied. Some of measures for
the collision force analysis of river ice and pier are proposed as
follows: bridge girder can adopt beam161 element with 3-node; pier
below the line of 1.30m above ice surface and ice sheet use solid164
element with 8-node; in order to accomplish the connection of
different elements, the rigid body with 0.01-0.05m thickness is defined
between solid164 and beam161; the contact type of ice and pier adopts
AUTOMATIC_SURFACE_TO_SURFACE, using symmetrical
penalty function algorithms; meshing size of pier below the line of
1.30m above ice surface should not less than 0.25×0.25×0.5m3. The
simulation results have the advantage of high precision by making a
comparison between measured and computed data. The research
results can be referred for collision force study between river ice and
pier.
Abstract: The innovative fuzzy estimator is used to estimate the
ground motion acceleration of the retaining structure in this study. The
Kalman filter without the input term and the fuzzy weighting recursive
least square estimator are two main portions of this method. The
innovation vector can be produced by the Kalman filter, and be
applied to the fuzzy weighting recursive least square estimator to
estimate the acceleration input over time. The excellent performance
of this estimator is demonstrated by comparing it with the use of
difference weighting function, the distinct levels of the measurement
noise covariance and the initial process noise covariance. The
availability and the precision of the proposed method proposed in this
study can be verified by comparing the actual value and the one
obtained by numerical simulation.
Abstract: In this study, hydroxyapatite (HA) composites are
prepared on addition of 30%CaO-30%P2O5-40%Na2 O based glass to
pure HA, in proportion of 2, 5, and 10 wt %. Each composition was
sintered over a range of temperatures. The quantitative phase
analysis was carried out using XRD and the microstructures were
studied using SEM. The density, microhardness, and compressive
strength have shown increase with the increasing amount of glass
addition. The resulting composites have chemical compositions that
are similar to the inorganic constituent of the mineral part of bone,
and constitutes trace elements like Na. X-ray diffraction showed no
decomposition of HA to secondary phases, however, the glass
reinforced-HA composites contained a HA phase and variable
amounts of tricalcium phosphate phase, depending on the amount of
bioglass added. The HA-composite material exhibited higher
compressive strength compared to sintered HA. The HA composite
reinforced with 10 wt % bioglass showed highest bioactivity level.