Merve SAĞIROĞLU, Mahyar MAALI, Abdulkadir Cüneyt AYDIN, Ahmet Mahmut KILIÇ
Merve SAĞIROĞLU, Mahyar MAALI, Abdulkadir Cüneyt AYDIN, Ahmet Mahmut KILIÇ
The behavior of beam-column semi-rigid connection plays an important role in the response of a steel moment resisting, stiffness and rotation capacity framed structure, especially under static loading conditions. In this study, the moment-rotation characteristics of semi-rigid bolted connections using web cleat connections with IPE standard profile is discussed, based on the experimental investigation. The study revealed that the moment resistance of beam-column semi-rigid connection is improved by increasing the height of the beam to the height of web cleat joint (H), and the increasing thickness of web and flange in web cleat joints. The aim was to provide necessary data to improve the Eurocode 3 and efficiently use residue IPE standard profiles, rather than send them back to the consumption cycle. While the resistance moment increased with an increase in H from Hmin to Hmax.
|
Kemal HACIEFENDİOĞLU, Gökhan DEMİR, Ahmet Can ALTUNIŞIK
Kemal HACIEFENDİOĞLU, Gökhan DEMİR, Ahmet Can ALTUNIŞIK
This paper studies to estimate the dynamic behavior of a demineralized water tank with a piled raft foundation system considering soil-pile-structure-fluid interaction to shock-ground motion. A three-dimensional finite element model of a coupled system is constituted in ANSYS software. Interaction between pile and soil is represented with the frictional contact element. The frictionless contact elements are utilized to model between the water and tank shell to allow for displacement of the free surface adjacent to the tank wall. Shell elements are used for the tank body and its vault. The dynamic analyses of the tank including soil-pile-structure-fluid interaction are presented by using shock response spectra. Ground shock acceleration time histories, generated by using a developed computer program based on Fortran programming language, produce shock response spectra. The effects of the different charge weights and distances from the charge center are examined in the analyses. Also, the effect of the water fill level in the tank and the number of piles is also investigated. The results of the research are presented with the directional displacements
and equivalent stresses. It seen from the analyses that the dynamic responses of the tank increase with the charge weight, while decreasing with the charge center distance. Moreover, the water fill level and the number of piles extremely affect the displacement and stress values of the coupled interaction system.
|
Concrete has a significant place in construction structures, is a material that can be
easily damaged due to incorrect design, incorrect material selection. Concrete may
be damaged by physical and chemical factors. One of these factors is the alkali-silica
reaction (ASR). ASTM C1260, is a short-term test method, and ASTM C227, is a longterm test method, are used to measure effect of alkali-silica reaction. In this study,
the effect of fly ash additive use with 0, 5, 10, 15, and 20 wt.% replacement of cement
was investigated in short- and long-term ASR test methods. For this purpose, while
samples prepared for ASTM C1260 were kept in NaOH solution 14-days, samples prepared for ASTM C227 were waited 360-days in normal water solution. As a result;
mortar bars with 20% fly ash additive ratio were classified as harmless for ASR in
both test methods.
|
Dynamic behavior is one of the most crucial characters in the railways structures.
One of the items which leads to precise identification of the dynamic behavior of railways is the soil depth beneath them. In this paper, an Euler-Bernoulli beam on a finite
depth foundation under accelerated moving load is presented. The dynamic equilibrium in the vertical direction is only regarded in accordance with the factor of finite
beams. In this study, the dynamic equilibrium of the soil in the vertical direction and
the sensitivity of soil depth are considered. The governing equations are simulated
by using Fourier transform method. Eventually, by considering the sequences of
shear waves, and different kinds of damping, displacement of the beam is obtained
for the various acceleration, times and soil depth. As a result, it is shown that, higher
acceleration is not dramatically effective on the beam displacement. Also, foundation
inertia causes a significant reduction in critical velocity and can augment the beam
response.
|
A previously benchmarked finite element model of a previously tested composite
plate shear wall-concrete filled (C-PSW/CF) was used to investigate the influence of
three concrete material models on in-plane cyclic inelastic wall response, using LSDyna. The concrete material models considered were the Winfrith, KCC and CSCM, all
available in LS-Dyna. Wall moment hysteresis, using the three concrete material
models, were obtained and compared. Individual contribution of the steel and concrete to total base moment was investigated for each wall with the three concrete material models. The numerical results obtained using the KCC and CSCM were compared
against the benchmarked results obtained using the Winfrith concrete material model.
Moment contribution of the steel web and the steel boundary on total base moment of
the steel part of the wall and moment contribution of the concrete web and concrete
boundary on total base moment of the concrete part of the wall were individually
investigated. The wall models with the KCC and CSCM concrete models were observed to cannot capture wall pinching which was captured by the Winfrith concrete
model. The wall strength was overpredicted by the CSCM concrete model and predicted reasonably by the KCC concrete model. Average axial stress distribution of the
infill concrete was obtained to investigate wall neutral axis and the maximum attained concrete strength using the three concrete models. Concrete axial stress distribution showed some level of confinement for the concrete models considered.
|
Building codes follow a common concept in designing buildings to achieve an acceptable
seismic performance. The objective underlying the concept is to ensure that
the buildings should be able to resist minor earthquake without damage, resist moderate
earthquake with some non-structural damage, and resist major earthquakes
without collapse, but some structural as well as non-structural damage. This study
aims to evaluate the performance-based seismic to come up with necessary recommendations
for both future practices, essential review, and restoration of existing
structures in Yemen. To do this real case studies incorporated, and nonlinear pushover
analysis is carried out. The analysis results presented and then assessed to find
out the conformity with the required performance. The structural sections assumed
at the beginning of the design, then the design repeated many times to achieve the
selected performance criteria (the plastic hinge properties and the maximum displacement).
|
In developing countries, the need for shelter, working area, shopping and entertainment
centers is increasing due to the increasing population effect. In order to meet
this need, it is necessary to turn to high-rise buildings. Significant damages have been
observed as a result of insufficient horizontal displacement stiffness of high-rise
buildings in major earthquakes in previous years. It is known that as the height of the
structure increases, the displacement demand of the structure also increases. Since
it is accepted that the structure will make inelastic deformation in the design of the
structure, these displacements increase to very high levels as the number of stories
increases. For this reason, damages can be much higher than expected. In order to
limit the level of damage that may occur in high-rise buildings, the horizontal displacement
of buildings is limited in many regulations in our age. This limitation is
possible by increasing the rigidity of the structures against horizontal displacement.
In recent years, the use of shear wall has increased due to the horizontal displacement
limitation in the regulations. The use of shear walls in buildings limits the horizontal
displacement. However, the choice of where the shear walls will be placed on
the plan is very important. Failure to place the shear walls correctly may result in
additional loads in the structure. It can also lead to torsional irregularity. In this
study, a 10-storey reinforced concrete building model was created. Shear wall at the
rate of 1% of the plan area of the building was used in the building. The shear walls
are arranged in different geometric shapes and different layouts. The earthquake
analysis of 5 different models were performed. Equivalent Earthquake Load, Mode
Superposition and Time History Analysis methods were used for earthquake analysis.
The results were compared and a proposal was made for the geometry and configuration
of the shear wall.
|
Historical structures reflect the historical and cultural properties of countries and also
contributes to the economy in terms of cultural tourism. Therefore, it is important to
understand the structural behavior of these kinds of structures under dynamics loads
such as earthquakes, etc. to protect and transfer them safely to future generations. For
this reason, this study aims to investigate the dynamic behavior of a reduced-scale
one-span masonry arch bridge constructed in laboratory conditions by performing experimental
and numerical analysis. Operational Modal Analysis (OMA) Technique was
performed under ambient vibrations for experimental study to determine modal parameters
of the reduced-scaled bridge model. Sensitive three-axial accelerometers
were located on critical points on the bridge span and signals originated by accelerometers
were collected to quantify the vibratory response of the scale bridge model. The
experimental natural frequencies, mode shapes and damping ratios resulting from
these measurements were figured out by using Enhanced Frequency Domain Decomposition
(EFDD) technique. ANSYS software was utilized to carry out 3D finite element
(FE) modeling of the reduced-scale masonry bridge and determine the natural frequencies
and mode shapes of the bridge numerically. Experimental results were compared
with FE analysis results of the bridge. Significant differences appeared when
comparing the results of the experimental and numerical with the initial conditions.
Therefore, the finite element model is calibrated by using the response surface (RS)
method according to the experimental results to minimize the uncertain finite element
modeling parameters of the reduced-scale bridge model such as material properties.
|
Base isolation system with lead rubber bearing (LRB) is commonly used to prevent
structure against to damage of earthquake. Design of LRB system is detailed in this
study. The isolated building with LRB design according to Uniform Building Code
(UBC-97) and fixed building were examined. The six-storey building with LRB and
fixed building were modelled in SAP2000 with the same dynamic loads. The relative
floor displacement and internal forces of the seismic isolated and fixed building are
compared. In addition, transverse and longitudinal reinforcement of any axis of seismic isolated and fixed building are compared. Analyse results showed that effectiveness of using seismic isolation system on building. The weight of longitudinal and
transverse reinforcement of isolated building is smaller than fixed building about
36%, 40% respectively.
|
Lean aims to maximize value while minimizing waste. Lean practices are likely to reduce
the number potential hazards and errors. The use of Lean practices in construction
is essential to experience less hazards. Benefitting from Lean practices has
gained much attention in the last decade. Especially, the destroying effect of hazards
and accidents is of utmost importance in terms of seeking for better strategies.
Within this context, Lean practices offer a wide variety of advantages and provide
means for achieving greater success in projects. This study investigates the use of
Lean practices in post disaster management. Since post disaster management includes
the activities to help community in rebuilding, Lean tools and techniques might be employed
to better handle post disaster management processes. The study also scrutinizes
the integration of Lean practices with the post disaster processes and encourages
the community to compete against the destroying effect of disasters thanks to
using Lean tools and techniques. The main contribution of this study is that it introduces
Lean practices to be used in the post disaster management processes, which
might potentially remove safety concerns in construction sites up to a great extent.
|
