Abstract: In recent years, the introduction of Pre Engineered Building (PEB) concept in the design of structures has helped in optimizing design. The adoptability of PEB in the place of Conventional Steel Building (CSB) design concept resulted in many advantages, including economy and easier fabrication. In this study, an industrial structure (Ware House) is analyzed and designed according to the Indian standards, IS 800-1984, IS 800-2007 and also by referring MBMA-96 and AISC-89. In this study, a structure with length 187m,width 40m,with clear height 8m and having R-Slope 1:10,isconsidered to carry out analysis& design for 2D frames (End frame, frame without crane and frame with 3 module cranes). The economy of the structure is discussed in terms of its weight comparison, between Indian codes (IS800-1984, IS800-2007) & American code (MBMA-96), & between Indian codes (IS800-1984, IS800-2007).
Abstract: There are several types of metal-based devices conceived as dampers for the seismic energy absorber whereby damages to the major structural components could be minimized for both new and existing structures. This paper aimed to develop and evaluate structural performance of slit circular shear panel damper for passive seismic energy protection by inelastic deformation. Structural evaluation was done using commercially available nonlinear FE simulation program. The main parameters considered are: diameter-to-thickness (D/t) ratio and slit length-to-width ratio (l/w). Depending on these parameters three different buckling mode and hysteretic behavior was found: yielding prior to buckling without strength degradation, yielding prior to buckling with strength degradation and yielding with buckling and strength degradation which forms pinching at initial displacement. The susceptible location at which the possible crack is initiated is also identified for selected specimens using rupture index.
Abstract: High temperature is one of the most detrimental
effects that cause important changes in concrete’s mechanical,
physical, and thermo-physical properties. As a result of these
changes, especially high strength concrete (HSC), may exhibit
damages such as cracks and spallings. To overcome this problem,
incorporating polymer fibers such as polypropylene (PP) in concrete
is a very well-known method. In this study, using RRH, as a
sustainable material, instead of PP fiber in HSC to prevent spallings
and improve physical and thermo-physical properties were
investigated. Therefore, seven HSC mixtures with 0.25 water to
binder ratio were prepared incorporating silica fume and blast furnace
slag. PP and RRH were used at 0.2-0.5% and 0.5-3% by weight of
cement, respectively. All specimens were subjected to high
temperatures (20 (control), 300, 600 and 900˚C) with a heating rate
of 2.5˚C/min and after cooling, residual physical and thermo-physical
properties were determined.
Abstract: Amongst the many priorities facing Libya following the 2011 uprising is the provision of a transport infrastructure that will meet the nation’s needs and not undermine its prospects for economic prosperity as with many developing economies non-technical issues such as management, planning and financing are the major barriers to the efficient and effective provision of transport infrastructure. This is particularly true in the case of the effective incorporation of sustainability criteria, and the research upon which this paper is based involves the examination of alternative ways of approaching this problem. It is probably fair to say that criteria that relate to sustainability have not, historically, featured strongly in Libya’s approach to the development of its transport infrastructure. However, the current reappraisal of how best to redevelop the country’s transport infrastructure that has been afforded by recent events may offer the opportunity to alter this. The research examines recent case studies from a number of countries to explore ways in which sustainability has been included as a criterion for planning and procurement decisions. There will also be an in-depth investigation into the Libyan planning and legislative context to examine the feasibility of the introduction of such sustainability criteria into the process of planning and procurement of Libya’s transport infrastructure.
Abstract: This paper deals with a proposal of a new
methodology for durability assessment of solidification product for
its safe further use. The new methodology is based on a review of the
current state of assessment of treated waste in Czech Republic and
abroad. The aim of the paper is to propose an optimal evaluation
methodology for verifying properties of solidification product to
ensure its safe further use in building industry.
Abstract: The use of low quality concrete has been identified as one of the main causes of the incessant collapse of buildings in Nigeria. Emphasis has been on the use of poor quality aggregates, poor workmanship and the use of lean concrete mix with low cement quantity as the reasons for the low quality of concrete used for building construction in Nigeria. Surveys conducted revealed that in the construction of most privately owned buildings where concrete trial mixes and concrete compressive strength quality assurance tests are not conducted, concretes used for building constructions are produced using the 1:2:4 mix ratio irrespective of the cement grade/strength class. In this paper, the possible role of the use of inappropriate cement grade/strength class as a cause of the incessant collapse of building in Nigeria is investigated. Investigation revealed that the compressive strengths of concrete cubes produced with Portland-limestone cement grade 32.5 using 1:2:4 and 1:1.5:3 mix ratios are less than the 25MPa and 30MPa cube strengths generally recommended for building superstructures and foundations respectively. Conversely, the compressive strengths of concrete cubes produced with Portland-limestone cement grade 42.5 using 1:2:4 and 1:1.5:3 mix ratios exceed the 25MPa and 30MPa generally recommended for building superstructures and foundations respectively. Thus, it can be concluded that the use of inappropriate cement grade (Portland-limestone cement grade 32.5), particularly for the construction of building foundations is a potential cause of the incessant collapse of buildings in Nigeria. It is recommended that the Standards Organisation of Nigeria should embark on creating awareness for Nigerians, particularly, the home owners and the roadside craftsmen that Portland-limestone cement grade 32.5 should not be used for the construction of building load-carrying members, particularly, building foundations in order to reduce the incessant incidence of collapsed building.
Abstract: Artificial Neural Networks (ANN) trained using backpropagation
(BP) algorithm are commonly used for modeling
material behavior associated with non-linear, complex or unknown
interactions among the material constituents. Despite multidisciplinary
applications of back-propagation neural networks
(BPNN), the BP algorithm possesses the inherent drawback of
getting trapped in local minima and slowly converging to a global
optimum. The paper present a hybrid artificial neural networks and
genetic algorithm approach for modeling slump of ready mix
concrete based on its design mix constituents. Genetic algorithms
(GA) global search is employed for evolving the initial weights and
biases for training of neural networks, which are further fine tuned
using the BP algorithm. The study showed that, hybrid ANN-GA
model provided consistent predictions in comparison to commonly
used BPNN model. In comparison to BPNN model, the hybrid ANNGA
model was able to reach the desired performance goal quickly.
Apart from the modeling slump of ready mix concrete, the synaptic
weights of neural networks were harnessed for analyzing the relative
importance of concrete design mix constituents on the slump value.
The sand and water constituents of the concrete design mix were
found to exhibit maximum importance on the concrete slump value.
Abstract: Heating, cooling and lighting appliances in buildings
account for more than one third of the world’s primary energy
demand. Therefore, main components of the building heating systems
play an essential role in terms of energy consumption. In this context,
efficient energy and exergy utilization in HVAC-R systems has been
very essential, especially in developing energy policies towards
increasing efficiencies. The main objective of the present study is to
assess the performance of a family house with a volume of 326.7 m3
and a net floor area of 121 m2, located in the city of Izmir, Turkey in
terms of energetic, exergetic and sustainability aspects. The indoor
and exterior air temperatures are taken as 20°C and 1°C, respectively.
In the analysis and assessment, various metrics (indices or indicators)
such as exergetic efficiency, exergy flexibility ratio and sustainability
index are utilized. Two heating options (Case 1: condensing boiler
and Case 2: air heat pump) are considered for comparison purposes.
The total heat loss rate of the family house is determined to be
3770.72 W. The overall energy efficiencies of the studied cases are
calculated to be 49.4% for Case 1 and 54.7% for Case 2. The overall
exergy efficiencies, the flexibility factor and the sustainability index
of Cases 1 and 2 are computed to be around 3.3%, 0.17 and 1.034,
respectively.
Abstract: Recently, to cope with the rapidly changing
construction trend with aging infrastructures, modular bridge
technology has been studied actively. Modular bridge is easily
constructed by assembling standardized precast structure members in
the field. It will be possible to construct rapidly and reduce
construction cost efficiently. However, the shape of the transverse
connection of T-type girder newly developed between the segmented
modules is not verified. Therefore, the verification of the connection
shape is needed. In this study, shape of the modular T-girder bridge
transverse connection was analyzed by finite element model that was
verified in study which was verified model of transverse connection
using Abaqus. Connection angle was chosen as the parameter. The
result of analyses showed that optimal value of angle is 130 degree.
Abstract: This research paper aims to identify, analyze and rank
factors affecting labor productivity in Spain with respect to their
relative importance. Using a selected set of 35 factors, a structured
questionnaire survey was utilized as the method to collect data from
companies. Target population is comprised by a random
representative sample of practitioners related with the Spanish
construction industry. Findings reveal the top five ranked factors are
as follows: (1) shortage or late supply of materials; (2) clarity of the
drawings and project documents; (3) clear and daily task assignment;
(4) tools or equipment shortages; (5) level of skill and experience of
laborers. Additionally, this research also pretends to provide simple
and comprehensive recommendations so that they could be
implemented by construction managers for an effective management
of construction labor forces.
Abstract: The measured data obtained from sensors in
continuous monitoring of civil structures are mainly used for modal
identification and damage detection. Therefore, when modal
identification analysis is carried out the quality in the identification of
the modes will highly influence the damage detection results. It is
also widely recognized that the usefulness of the measured data used
for modal identification and damage detection is significantly
influenced by the number and locations of sensors. The objective of
this study is the numerical implementation of two widely known
optimum sensor placement methods in beam-like structures.
Abstract: The reduction of greenhouse gases emissions is highly
discussed ecological theme at present. In addition to power industry
also main production sectors of binders, i.e. cement, air and hydraulic
lime are very sensitive to these questions. One of the possibilities
how CO2 emissions can be reduced directly at clinker burnout is
represented by partial substitution of lime with a material containing
limy ions at absence of carbonate group. Fluidised fly ash is one of
such potential raw materials where CaO can be found free and also
bound in anhydrite, CaSO4. At application of FBC (fluidized bed
combustion) fly ash with approximate 20% CaO content and its
dosing ratio to high percent lime 1:2, corresponding stechiometrically
to the preparation of raw material powder, approximately 0,37 t CO2
per 1 ton of one-component cement would be released at clinker
burnout compared to 0,46 t CO2 when orthodox raw materials are
used. The reduction of CO2 emissions thus could reach even 20%.
Abstract: This entry concerned with dense silica bricks
microstructure was produced as a part of a project within the
Technology Agency of the Czech Republic which is being
implemented in cooperation of the biggest producer of refractories
the P-D Refractories CZ company with the research organisation
Brno University of Technology. The paper is focused on the
influence of mixture homogenisation and the influence of grain size
of the mineraliser on the resulting utility properties of the material as
well as its microstructure. It has a decisive influence on the durability
of the material in a building structure. This paper is a continuation of
a previously published study dealing with the suitability of various
types of mineralising agents in terms of density, strength and mineral
composition of silica brick.
The entry describes the influence of the method of mixture
homogenisation and the influence of granulometry of the applied Femineralising
agent on the resulting silica microstructure. Porosity,
density, phase composition and microstructure of the experimentally
prepared silica bricks samples were examined and the results were
discussed in context with the technology of homogenisation and
firing temperature used. The properties of silica bricks samples were
compared to the sample without any Fe-mineraliser.
Abstract: Well-designed composite steel and concrete structures
highlight the good material properties and lower the deficiencies of
steel and concrete, in particular they make use of high tensile strength
of steel and high stiffness of concrete. The most common composite
steel and concrete structure is a simply supported beam, which
concrete slab transferring the slab load to a beam is connected to the
steel cross-section. The aim of this paper is to find the most adequate
numerical model of a simply supported composite beam with the
cross-sectional and material parameters based on the results of a
processed parametric study and numerical analysis. The paper also
evaluates the suitability of using compact concrete with the
lightweight aggregates for composite steel and concrete beams. The
most adequate numerical model will be used in the resent future to
compare the results of laboratory tests.
Abstract: This paper attempts to evaluate the effect of fire
damage on concrete by using nonlinear resonance vibration method,
one of the nonlinear nondestructive method. Concrete exhibits not
only nonlinear stress-strain relation but also hysteresis and discrete
memory effect which are contained in consolidated materials.
Hysteretic materials typically show the linear resonance frequency
shift. Also, the shift of resonance frequency is changed according to
the degree of micro damage. The degree of the shift can be obtained
through nonlinear resonance vibration method. Five exposure
scenarios were considered in order to make different internal micro
damage. Also, the effect of post-fire-curing on fire-damaged concrete
was taken into account to conform the change in internal damage.
Hysteretic nonlinearity parameter was obtained by amplitudedependent
resonance frequency shift after specific curing periods. In
addition, splitting tensile strength was measured on each sample to
characterize the variation of residual strength. Then, a correlation
between the hysteretic nonlinearity parameter and residual strength
was proposed from each test result.
Abstract: This paper focuses on the presentation of results
which were obtained as a part of the project FR-TI 3/742: “System of
Lightweight Materials for Finishing of Buildings with Waste Raw
Materials”. Attention was paid to the light weighting of polymermodified
mortars applicable as adhesives, screeds and repair mortars.
In terms of repair mortars, they were ones intended for the sanitation
of aerated concrete.
Abstract: The effect of particle size on shear strength of
granular materials are investigated using direct shear tests. Small
direct shear test (60 mm by 60 mm by 24 mm deep) were conducted
for particles passing the sieves with opening size of 2.36 mm.
Meanwhile, particles passing the standard 20 mm sieves were tested
using large direct shear test (300 mm by 300 mm by 200 mm deep).
The large direct shear tests and the small direct shear tests carried out
using the same shearing rate of 0.09 mm/min and similar normal
stresses of 100, 200 and 300 kPa. The results show that the peak and
residual shear strength increases as particle size increases.
Abstract: The paper deals with current issues in research of
advanced methods to increase reliability of traditional timber
structural elements. It analyses the issue of strengthening of bent
timber beams, such as ceiling beams in old (historical) buildings with
additional concrete slab in combination with externally bonded fibre -
reinforced polymer. The paper describes experimental testing of
composite timber-concrete beam with FRP reinforcement and
compares results with FEM analysis.
Abstract: The majority of contemporary insulation materials
commonly used in the building industry is made from non-renewable
raw materials; furthermore, their production often brings high energy
costs. A long-term trend as far as sustainable development is
concerned has been the reduction of energy and material demands of
building material production. One of the solutions is the possibility of
using easily renewable natural raw material sources which are
considerably more ecological and their production is mostly less
energy-consuming compared to the production of normal insulations
(mineral wool, polystyrene). The paper describes the results of
research focused on the development of thermal and acoustic
insulation materials based on natural fibres intended for floor
constructions. Given the characteristic open porosity of natural fibre
materials, the hygrothermal behaviour of the developed materials was
studied. Especially the influence of relative humidity and temperature
on thermal insulation properties was observed.
Abstract: This paper involved the performance of a hightemperature
X-Ray powder diffraction analysis (XRD) of a sample of
chemical gypsum generated in the production of titanium white; this
gypsum originates by neutralizing highly acidic water with limestone
suspension. Specifically, it was gypsum formed in the first stage of
neutralization when the resulting material contains, apart from
gypsum, a number of waste products resulting from the
decomposition of ilmenite by sulphuric acid. So it can be described as
red titanogypsum. By conducting the experiment using XRD
apparatus Bruker D8 Advance with a Cu anode (λkα=1.54184 Å)
equipped with high-temperature chamber Anton Paar HTK 16, it was
possible to identify clearly in the sample each phase transition in the
system of CaSO4·xH2O.