Transportation
planning relies on traffic demand forecasting process. The conventional process
is impeded by extensive amount of socioeconomic data. One of the most
widely-used models which mitigate this problem is the TransCAD Model. This
model is rarely used in Gaza Strip for traffic demand forecasting, and most of
the practices depend mainly on a constant growth rate of traffic. Therefore,
the main objective of this research is to apply this model in Gaza City for
traffic estimation. This model estimates the origin-destination matrix based on
traffic count. The traffic count was carried out at 36 intersections
distributed around Gaza City. The results of traffic flow estimation obtained
from TransCAD are assigned to the Gaza maps using the GIS techniques for
spatial analysis. It is shown that the most congested area at present is the
middle of the city especially at Aljala-Omer Almokhtar intersection. Therefore,
improvement scenarios of this area should be carried out. The results of
calibration of traffic flow estimation show that the differences between the
estimated and the actual flows were less than 10%. In addition, network
evaluation results show that the network is expected to be more congested in
2015. This work can be used by transportation planners for testing any network
improvement scenarios and for studying their network performance.
Thursday, 2 July 2015
Seismic Response and Stability Analysis of Single Hinged Articulated Tower
Offshore
structures subjected to wave, earthquake or wind loads or a combination of
these loads show non-linear transient behaviour. As oceanic waves are better
modelled as stochastic process, there is a need to investigate the stochastic
stability of flexible offshore structures as well. Present study has been
carried out to determine seismic response of Single Hinged Articulated Tower
(SHAT) under different categories of wave loads and earthquake followed by its
dynamic stability analysis. Different phases of wave/earthquake loading on SHAT
have been explored to investigate dynamic instabilities existing during each
phase. Two dimensional phase plots have been used to identify phases of dynamic
instability existing within the responses of SHAT under various conditions of
loading.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Influence of the Elastic Modulus of the Soil and Concrete Foundation on the Displacements of a Mat Foundation
The
objective is to highlight the soil-structure interaction particularly the
influence of the rigidities of the soil and the concrete on the subgrade
reaction (k) and the displacements of the mat foundation subjected to vertical
loads. From plate theory and the soil-structure interaction, the general equation
is reached. This equation depends more on the subgrade properties than the
concrete foundation properties. Consequently, the behavior of the mat
foundation is more influenced by soil properties than the concrete.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Safety Assurance for Challenging Geotechnical Civil Engineering Constructions in Urban Areas
Safety
is the most important aspect during design, construction and service time of
any structure, especially for challenging projects like high-rise buildings and
tunnels in urban areas. A high level design considering the soil-structure-
interaction, based on a qualified soil investigation is required for a safe and
optimised design. Due to the complexity of geotechnical constructions the
safety assurance guaranteed by the 4-eye-principle is essential. The
4-eye-principle consists of an independent peer review by publicly certified
experts combined with the observational method. The paper presents the
fundamental aspects of safety assurance by the 4-eye-principle. The application
is explained on several examples, as deep excavations, complex foundation
systems for high-rise buildings and tunnel constructions in urban areas. The
experiences made in the planning, design and construction phases are explained
and for new inner urban projects recommendations are given.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Experimental Behavior of Partially Prestressed High Strength Concrete Beams
It currently becomes more desirable as it has
better mechanical properties and durability performance. Major defect of fully
prestressed concrete is its low ductility; it may produce less alarming signs
than ordinary reinforced concrete via smaller deflection and limited cracking.
Therefore, partially prestressing is considered an intermediate design between
the two extremes. So, combining high strength concrete with partial
prestressing will result in a considerable development in the use of
prestressed concrete structures regarding the economical and durability view
points. This study presents the results of seven partially prestressed high
strength concrete beams in flexure. The tested beams are used to investigate
the influence of concrete compressive strength, prestressing steel ratio and
flange width on the behavior of partially prestressed beams. The experimentally
observed behaviors of all beams were presented in terms of the cracking load,
ultimate load, deflection, cracking behavior and failure modes.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
3-D Modelling of the Confederation Bridge Using Data of Full Scale Tests
Long-span
bridges are special structures that require advanced analysis techniques to
examine their performance. This paper presents a procedure developed to model
the Confederation Bridge using 3-D beam elements. The model was validated using
the data collected before the opening of the bridge to the public. The bridge
was instrumented to conduct fullscale static and dynamic tests. The static
tests were to measure the deflection of the bridge pier while the dynamic tests
to measure the free vibrations of the pier due to a sudden release of the
static load. Confederation Bridge is one of the longest reinforced concrete
bridges in the world. It connects the province of Prince Edward Island and the
province of New Brunswick in Canada. Due to its strategic location and vital
role as a transportation link between these two provinces, it was designed using
higher safety factors than those for typical highway bridges. After validating
the present numerical model, a procedure was developed to evaluate the
performance of similar bridges subjected to traffic and seismic loads. It is of
interest to note that the foundation stiffness and the modulus of elasticity of
the concrete have significant effects on the structural responses of the
Confederation Bridge.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Similarity Study on Snowdrift Wind Tunnel Test
The
model for snowdrift wind tunnel test needs to be similar with the prototype.
Based on detailed analysis in aspects of geometry, kinematics and dynamics, the
major similarity parameters that need to be satisfied are gained. The
contradiction between the Reynolds number and Froude number as well as the
problem of time scale is introduced, and the selections of the model parameters
are specified. Lastly, an example of snowdrift wind tunnel test by adoption of
quartz sand as the model of snow grains is presented. The flow field and the
snow distributions on a typical stepped roof were investigated. The results
show that the flow filed characters are in good agreement with the field
observations, and the stepped roof snow depth distributions are basically
consistent with the observation results.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Intrinsic Compression Behavior of Remolded and Reconstituted Clays-Reappraisal
Evaluating
the impacts of soil structure on mechanical behavior for natural sedimentary
clays is an important issue in geotechnical engineering. Burland introduced
void index for normalizing the compression curves of various remolded and
reconstituted clays to obtain the intrinsic compression line, which provides a
reference framework to assess the in-situ compression behavior. However, it
does not quantitatively account for the effects of initial water content on
compressive behavior of remolded and reconstituted clays and the initial water
contents of clays are not always limited to 1.0 - 1.5 times the liquid limits
defined by Burland. A modification based on collected tests data was presented
on the expressions of and defined by Burland. Extensive oedometer test
data were also collected on various remolded and reconstituted soils with
distinct liquid limits and initial water contents to verify the validity of
modified expressions. A normalized compression line deduced by intrinsic
compression line is proposed in the e-log p plot, which can be used to evaluate
the effects of soil structure quantitatively on the intact compressive behavior
for natural sedimentary clays.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Significance Analysis of Flexural Behaviour of Hybrid Sandwich Panels
Two
different types of natural fibers reinforced plastics (NFRP) laminate were
incorporated into the new sandwich panel as an intermediate layer. The
significance analysis in this research has been carried out using analysis of
variance (ANOVA). As the aim of the analysis is to select the most appropriate
natural fiber composites for the intermediate layer, the experiments were
arranged as a single factor experiment in which 3 levels of a factor have been
examined. The factor refers to the type of intermediate layer used in the
sandwich panel. The result of this study shows that the incorporation of
intermediate layer has significantly enhanced the load carrying capacity of the
sandwich panels.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Pedestrian Countdown Signals: What Impact on Safe Crossing?
Crossing
episodes of over 5000 pedestrians were videotaped and analyzed using
multivariate statistical methods. Details of timing of pedestrian crossing as
well as information about vehicular traffic and signal timing were carefully
coded for each pedestrian. Significant safety benefits of the PCS system were
found on the long crossings over a street with high vehicular volumes: most
pedestrians were able to effectively increase their walking speed to complete
their crossing without committing the exit violation—even if they have already
committed the entry violation. However, on the short crossing with light
vehicular traffic, PCS was generally ineffective in preventing the entry
violations from becoming exit violations. Over there, many pedestrians felt
safe enough to walk over a short crossing with no apparent vehicular traffic in
sight instead of waiting for a green signal. The length of crossing and volume
of interfering vehicular traffic were consistently found the most significant
variables affecting the crossing violation rates of different categories of
pedestrians. Crossing violation rates were the highest for runners, bicyclists
and older males. Crossing violation characteristics were found to be consistent
over time.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Wednesday, 1 July 2015
The Effect of Incorporation of Ferrite Nano-particles on Compressive Strength and Re-sistivity of Self-Compacting Concrete
The data
of XRD clarified that the sample was formed in single phase spinel structure
without any extra peaks indicating non-existence of any secondary phase. The
HRTEM micrograph indicated that the particles were in an agglomerated state due
to the absence of surfactant and high magnetic properties of Mn-Ferrite
nanoparticles. The mechanical properties were measured at different ratios of
nano-Ferrite to concrete. The obtained values of mercury intrusion porosimetry
(MIP) indicated that the addition of Mn-Ferrite nanoparticles increased the
compressive strength and decreased the total intrusion volume. This was due to
the rapid consuming of Ca(OH)2 which was formed during hydration of Portland
cement especially at early ages due to the high reactivity of MnFe2O4
nanoparticles. Moreover, MnFe2O4 nanoparticles recovered the particle packing
density of the blended cement, leading to a reduced volume of pores in the
cement paste.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Seismic Capacity Assessment of Existing RC Buildings in The Sudan by Using Pushover Analysis
The
objective of this paper is to assess the seismic performance of existing RC
buildings in The Sudan. Four typical buildings were investigated using pushover
analysis according to ATC-40. They were designed according to the Regulations
for earthquake-resistant design of buildings in Egypt (ESEE) and International
Building Code (IBC2012). Results showed that the buildings designed considering
by ESEE and IBC2012 loads were found adequate and satisfied the Immediate
Occupancy (IO) acceptance criteria according to ATC-40. The comparison of the
pushover curve shows that the stiffness of frames is larger when using ESEE
Regulations compared to the IBC2012 design. This means that ESEE design
procedure provides a greater capability to resist seismic load than the IBC2012
design.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Applications and Prospects of Fiber Reinforced Concrete in Industrial Floors
Upon the
view of this work, industrial floor is a vital structure due to its relation to
quality of production, labor comfort, and human health. Flooring costs may
reach 20% of single-story building construction expenditure, and the
consumption of concrete for floors may come to 40% - 50% of the total size of
concrete. Thereby, the efficient design of floor will reduce materials
consumption and labor, and will increase the endurance of the floor. Fiber
reinforcement reduces the thickness of the subfloor about 20% - 30%, hence
enabling to reduce the consumption of cement and fillers. The use of fiber
meshes will enable to save 30% - 40% of steel. Despite the flexible use of
fiber in concrete reinforcement saves effort and money, still fiber reinforced
concrete is lacking additional regulations in Jordan.
Evaluation of Water Distribution Jointed Pipe Networks under Transient Ground Motions
wave
propagation. First, using finite element method and solid elements, different
kinds of currently used connections in the network are modeled, and their
nonlinear behavior in all directions is obtained. Second, a 950-meter long
network consisting of ductile iron pipes segments of 6-meter length and springs
characterizing the connections, are modeled using beam elements.
Three-component displacement record of the Tabas earthquake is applied to the
network considering the time lag between support inputs, and the nonlinear
soil-pipe interaction. The record is applied once in North-South direction and
once in East-West direction with different wave propagation velocities. Results
of interest such as stress values and rotations at various points of the
network are then obtained, and critical points are introduced in each
direction. Results show that the points other than the critical ones at the network
intersections remain elastic.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Effect of Using Stone Cutting Slurry Waste (Al-Khamkha) on the Compaction Characteristics of Jerash Cohesive Soil
The
aim of this research is to study the effect of using (Al-KHAMKHA) is stone
cutting slurry waste local name in JORDAN on the unit weight and moisture
content of Jerash cohesive soil Al-Khamkha which is the local name of the stone
cutting slurry waste which is produced during the cutting operation, This water
carries large amounts of stone powder, which leads to complex nature of
environmental problem so these waste material needs to be utilized meaningfully
in economic way. The degree of compaction of a soil is measured in terms of its
dry unit weight Al-Khamkha mixed with Jerash cohesive soil at different amount
ranges from 0%, 5%, 10%, 15%, up to 50% and compaction characteristics of
Jerash cohesive soil without and with different amount of Al-Khamkha was
studied. This investigation show that as the amount of Al-Khamkha increase from
0% to 15%, the dry unit weight of Jerash cohesive soil increase from 14.4 KN/m3
at 0% of Al-Khamkha to 16.5 KN/m3 at 15% and after that .any increase of
Al-Khamkha decrease the dry unit weight. On the other hand, the optimum water
content of the Jerash cohesive soil was increases with increasing the
percentage of Al-Khamkha on the cohesive soil.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Computational Finite Element Modelling of Structural Behaviours of Precast Sandwiched Foamed Concrete Slab
The
structural behaviour of Precast Lightweight Foamed Concrete Panel (PLFP) under
flexural load is investigated by using ABAQUS 6.13. The PLFP is made up of two
Whyte’s with a polystyrene insulator placed in between them using a double
shear truss connector of diameter 6mm placed at an angle 45°. The panel is
reinforced with both vertical and horizontal steel reinforcement of 9 mm
diameter. Four panels with varying dimensions are simulated to investigate
their Ultimate Strength and Load-deflection profile. The results show that the
length to thickness ratio of the panel is the major contributing factor to the
ultimate strength of the PLFP. From the load deflection curve, the panel with
the least deflection has the highest thickness which also results in a high
ultimate strength recorded at 34.43 KN.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Comparative Studies of Steel, Bamboo and Rattan as Reinforcing Bars in Concrete: Tensile and Flexural Characteristics
The
beams were subjected to centre-point flexural loading according to BS 1881 to
evaluate the flexural behaviour. The YS of bamboo and rattan bars were 13% and
45% of that of steel respectively, while their UTS were 16% and 62% of that of
steel in the same order. The elongation of bamboo, rattan and steel were 7.42%,
10% and 14.7% respectively. The natural rebars were less than the 12% minimum
requirement of BS 4449. The load-deflection plots of bamboo and steel RC beams
were quadratic, while rattan RC beams had curvilinear trend. The stiffness of
bamboo RC beams (BB) and rattan RC beams (RB) were 32% and 13.5% of the
stiffness of steel RC beams (SB). The post-first crack residual flexural
strength was 41% for BB and SB, while RB was 25%. Moreover, the moment
capacities of BB and RB corresponded to 51% and 21% respectively of the
capacity of steel RC beams. The remarkable gap between the flexural capacities
of the natural rebars and that of steel can be traced not only to the tensile
strength but also the weak bonding at the bar-concrete interface. It can be
concluded that the bamboo bars are suitable rebars for non-load bearing and
lightweight RC flexural structures, while more pre-strengthening treatment is
required more importantly for rattan for improved interfacial bonding and
load-carrying capacity.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Compressive and Flexural Behaviour of Unstressed Concrete Substructure in Cassava Effluent Contaminated Soils
The
rate of deterioration is affected by the loading condition, and more
importantly the physical and chemical nature of the host environments. This
paper reports the experimental investigation of unstressed concrete
substructure in the natural (uncontaminated) and cassava’s hydrocyanide
effluent-polluted soils on the compressive and flexural strengths of buried
concrete specimens for a maximum of 84 days. The compressive strengths of the
cubes were tested every 7 days until the 84th day, while the beams were only
subjected to third-point loading flexural tests at age 84 days. The compressive
strength of concrete specimens in the two soil environments increased, though
the trend was lower in the polluted soil. The strength reduced by 2.50% to
9.47% between the 7th and 28th days, but steadily between the 28th and 84th
days with strength loss of 9.95% (COV = 2.64%). The load-deflection curves were
quadratic for the beams in the two geo-environments. The beams in
cyanide-polluted soil lost 34.5% of its flexural stiffness, while its loss of
load-carrying capacities at the first crack and ultimate failure was 15.8% and
20% respectively. Higher degree of deterioration is certain for loaded concrete
substructures in similar conditions. Hence, prior knowledge of soil chemistry
is crucial to determining suitable concrete grade and nominal cover for durable
substructural elements.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Influence of Mechanical Properties of Concrete and Soil on Solicitations of Mat Foundation
These
two parameters are dependent on the geometrical and mechanical characteristics
of the system. Results of this study show a sensitivity of solicitations to
variations of geometrical and mechanical characteristics of the model. Although
solicitations in the plate are sensitive to mechanical properties of concrete,
these solicitations are strongly influenced by the mechanical and geometrical
characteristics of the soil mass. However, it should be noted that the
influence of Eb is denoted in the center of the plate whereas the Es feels
almost in the same manner over the entire extent of the plate. This study also
shows that for the same load cases, the values of the torsion moment and shear
stress are not significant those of bending moments and normal stresses,
respectively.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Analysis of the Probability Model of Wind Load on the Offshore Wind Turbine
According
to the actual measurement data, probability models of horizontal wind load were
obtained based on wind velocity statistic and power spectral density function
of fluctuating wind velocity through stochastic sampling and using spectrum
analysis method. Through the comparison of two models, probability models of
horizontal wind load based on probability models of fluctuating wind velocity
were obtained by revising the mean and variance of fluctuating wind velocity.
Results show that the variance takes lower value when the power spectral
density function of fluctuating wind velocity is used to obtain the probability
model of horizontal wind load. The quadratic term of fluctuating wind velocity
takes a small contribution value in total wind load with almost no contribution
to the model of horizontal wind load. It is convenient for practical
engineering to obtain the models of horizontal wind load by using probability
models of fluctuating wind velocity.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Sunday, 28 June 2015
Analysis of the Probability Model of Wind Load on the Offshore Wind Turbine
According
to the actual measurement data, probability models of horizontal wind load were
obtained based on wind velocity statistic and power spectral density function
of fluctuating wind velocity through stochastic sampling and using spectrum
analysis method. Through the comparison of two models, probability models of
horizontal wind load based on probability models of fluctuating wind velocity
were obtained by revising the mean and variance of fluctuating wind velocity.
Results show that the variance takes lower value when the power spectral
density function of fluctuating wind velocity is used to obtain the probability
model of horizontal wind load. The quadratic term of fluctuating wind velocity
takes a small contribution value in total wind load with almost no contribution
to the model of horizontal wind load. It is convenient for practical
engineering to obtain the models of horizontal wind load by using probability
models of fluctuating wind velocity.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Influence of Mechanical Properties of Concrete and Soil on Solicitations of Mat Foundation
This
work studies the influence of mechanical and geometrical characteristics of the
concrete and the soil on the stresses in a mat foundation. In this study, the
soil-structure interaction is modeled by two parameters, the modulus of
subgrade vertical reaction (k) and the modulus of subgrade horizontal reaction
(2T). These two parameters are dependent on the geometrical and mechanical
characteristics of the system. Results of this study show a sensitivity of
solicitations to variations of geometrical and mechanical characteristics of
the model. Although solicitations in the plate are sensitive to mechanical
properties of concrete, these solicitations are strongly influenced by the
mechanical and geometrical characteristics of the soil mass. However, it should
be noted that the influence of Eb is denoted in the center of the plate whereas
the Es feels almost in the same manner over the entire extent of the plate.
This study also shows that for the same load cases, the values of the torsion
moment and shear stress are not significant those of bending moments and normal
stresses, respectively.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Compressive and Flexural Behaviour of Unstressed Concrete Substructure in Cassava Effluent Contaminated Soils
Concrete
research is gradually shifting from the conventional strength-based approach to
durability-centred in the past decade. Durability is the measure of the
robustness of constructed facilities against deterioration tendencies. The rate
of deterioration is affected by the loading condition, and more importantly the
physical and chemical nature of the host environments. This paper reports the
experimental investigation of unstressed concrete substructure in the natural
(uncontaminated) and cassava’s hydrocyanide effluent-polluted soils on the
compressive and flexural strengths of buried concrete specimens for a maximum
of 84 days. The compressive strengths of the cubes were tested every 7 days
until the 84th day, while the beams were only subjected to third-point loading
flexural tests at age 84 days. The compressive strength of concrete specimens
in the two soil environments increased, though the trend was lower in the
polluted soil. The strength reduced by 2.50% to 9.47% between the 7th and 28th
days, but steadily between the 28th and 84th days with strength loss of 9.95%
(COV = 2.64%). The load-deflection curves were quadratic for the beams in the
two geo-environments. The beams in cyanide-polluted soil lost 34.5% of its
flexural stiffness, while its loss of load-carrying capacities at the first
crack and ultimate failure was 15.8% and 20% respectively. Higher degree of
deterioration is certain for loaded concrete substructures in similar
conditions. Hence, prior knowledge of soil chemistry is crucial to determining
suitable concrete grade and nominal cover for durable substructural elements.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Comparative Studies of Steel, Bamboo and Rattan as Reinforcing Bars in Concrete: Tensile and Flexural Characteristics
Three
beams of concrete strength 20 N/mm2 at age 28 days were separately reinforced
with bamboo, rattan and steel bars of same percentage, while the stirrups were
essentially mild steel bars. The beams were subjected to centre-point flexural
loading according to BS 1881 to evaluate the flexural behaviour. The YS of
bamboo and rattan bars were 13% and 45% of that of steel respectively, while
their UTS were 16% and 62% of that of steel in the same order. The elongation
of bamboo, rattan and steel were 7.42%, 10% and 14.7% respectively. The natural
rebars were less than the 12% minimum requirement of BS 4449. The
load-deflection plots of bamboo and steel RC beams were quadratic, while rattan
RC beams had curvilinear trend. The stiffness of bamboo RC beams (BB) and
rattan RC beams (RB) were 32% and 13.5% of the stiffness of steel RC beams
(SB). The post-first crack residual flexural strength was 41% for BB and SB,
while RB was 25%. Moreover, the moment capacities of BB and RB corresponded to
51% and 21% respectively of the capacity of steel RC beams. The remarkable gap
between the flexural capacities of the natural rebars and that of steel can be
traced not only to the tensile strength but also the weak bonding at the
bar-concrete interface. It can be concluded that the bamboo bars are suitable
rebars for non-load bearing and lightweight RC flexural structures, while more
pre-strengthening treatment is required more importantly for rattan for
improved interfacial bonding and load-carrying capacity.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Computational Finite Element Modelling of Structural Behaviours of Precast Sandwiched Foamed Concrete Slab
The
structural behaviour of Precast Lightweight Foamed Concrete Panel (PLFP) under
flexural load is investigated by using ABAQUS 6.13. The PLFP is made up of two
Whyte’s with a polystyrene insulator placed in between them using a double
shear truss connector of diameter 6mm placed at an angle 45°. The panel is
reinforced with both vertical and horizontal steel reinforcement of 9 mm
diameter. Four panels with varying dimensions are simulated to investigate
their Ultimate Strength and Load-deflection profile. The results show that the
length to thickness ratio of the panel is the major contributing factor to the
ultimate strength of the PLFP. From the load deflection curve, the panel with
the least deflection has the highest thickness which also results in a high
ultimate strength recorded at 34.43 KN.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Effect of Using Stone Cutting Slurry Waste (Al-Khamkha) on the Compaction Characteristics of Jerash Cohesive Soil
This
water carries large amounts of stone powder, which leads to complex nature of
environmental problem so these waste material needs to be utilized meaningfully
in economic way. The degree of compaction of a soil is measured in terms of its
dry unit weight Al-Khamkha mixed with Jerash cohesive soil at different amount
ranges from 0%, 5%, 10%, 15%, up to 50% and compaction characteristics of
Jerash cohesive soil without and with different amount of Al-Khamkha was
studied. This investigation show that as the amount of Al-Khamkha increase from
0% to 15%, the dry unit weight of Jerash cohesive soil increase from 14.4 KN/m3
at 0% of Al-Khamkha to 16.5 KN/m3 at 15% and after that .any increase of
Al-Khamkha decrease the dry unit weight. On the other hand, the optimum water
content of the Jerash cohesive soil was increases with increasing the percentage
of Al-Khamkha on the cohesive soil.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Effects of Building Configuration on Seismic Performance of RC Buildings by Pushover Analysis
These
existing reinforced concrete buildings need to be evaluated to determine the
capacity to resist seismic loads. The behavior of a building during earthquakes
depends critically on its overall shape, size and geometry. Conventional
approach to earthquake resistant design of buildings depends upon providing the
building with strength, stiffness and inelastic deformation capacity which are
great enough to withstand a given level of earthquake-generated force. This is
generally accomplished through the selection of an appropriate building
configuration and the careful detailing of structural members. In this
research, nonlinear pushover analysis has been used to evaluate the seismic
performance of three buildings with three different plans having same area and
height. This method determines the base shear capacity of the building and
performance level of each part of building under varying intensity of seismic
force. The results of effects of different plan on seismic response of
buildings have been presented in terms of displacement, base shear and plastic
hinge pattern.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Evaluation of Water Distribution Jointed Pipe Networks under Transient Ground Motions
a
new method is proposed to evaluate the seismic behavior of buried jointed water
pipeline networks subjected to wave propagation. First, using finite element
method and solid elements, different kinds of currently used connections in the
network are modeled, and their nonlinear behavior in all directions is
obtained. Second, a 950-meter long network consisting of ductile iron pipes
segments of 6-meter length and springs characterizing the connections, are
modeled using beam elements. Three-component displacement record of the Tabas
earthquake is applied to the network considering the time lag between support
inputs, and the nonlinear soil-pipe interaction. The record is applied once in
North-South direction and once in East-West direction with different wave
propagation velocities. Results of interest such as stress values and rotations
at various points of the network are then obtained, and critical points are
introduced in each direction. Results show that the points other than the
critical ones at the network intersections remain elastic.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Applications and Prospects of Fiber Reinforced Concrete in Industrial Floors
Flooring
costs may reach 20% of single-story building construction expenditure, and the
consumption of concrete for floors may come to 40% - 50% of the total size of
concrete. Thereby, the efficient design of floor will reduce materials
consumption and labor, and will increase the endurance of the floor. Fiber
reinforcement reduces the thickness of the subfloor about 20% - 30%, hence
enabling to reduce the consumption of cement and fillers. The use of fiber
meshes will enable to save 30% - 40% of steel. Despite the flexible use of
fiber in concrete reinforcement saves effort and money, still fiber reinforced
concrete is lacking additional regulations in Jordan.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Seismic Capacity Assessment of Existing RC Buildings in The Sudan by Using Pushover Analysis
The
evaluation of seismic performance of existing buildings has received a great
attention. Current research works and observations indicate that The Sudan have
low-to-moderate seismic regions. Most of existing buildings are designed only
for gravity load. The objective of this paper is to assess the seismic
performance of existing RC buildings in The Sudan. Four typical buildings were
investigated using pushover analysis according to ATC-40. They were designed
according to the Regulations for earthquake-resistant design of buildings in
Egypt (ESEE) and International Building Code (IBC2012). Results showed that the
buildings designed considering by ESEE and IBC2012 loads were found adequate
and satisfied the Immediate Occupancy (IO) acceptance criteria according to
ATC-40. The comparison of the pushover curve shows that the stiffness of frames
is larger when using ESEE Regulations compared to the IBC2012 design. This
means that ESEE design procedure provides a greater capability to resist
seismic load than the IBC2012 design.
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/
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