Abstract: Natural Disasters have always occurred through earth life. As human life developed on earth, he faced with different disasters. Since disasters would destroy his living areas and ruin his life, he learned how to respond and overcome to these matters. Nowadays, in the era of industrialized world and informatics, the man kind seeks for stages and classification of pre and post disaster process in order to identify a framework in these circumstances. Because too many parameters complicate these frameworks and proceedings, it seems that this goal has not been properly established yet and the only resource is guidelines of UNDRO (1982) [1]. This paper will discuss about temporary housing as one of an approved stage in disaster management field and investigate the affects of disapproval or dismissal of this at two earthquakes which took place in Iran.
Abstract: When earthquakes strike the city it results in great loss of lives. The present paper talks about a new innovative design system (MegEifel) for buildings which has a mechanism to mitigate deaths in case any earthquake strikes the city. If buildings will be designed according to MegEifel design then the occupants of the building will be safe even when they are in sleep or are doing day wise activities during the time earthquake strikes. The core structure is suggested to be designed on the principle that more deep the foundations are, the harder it is to uproot the structure. The buildings will have an Eifel rod dug deep into earth which will help save lives in tall buildings when earthquake strikes. This design takes a leverage of protective shells to save lives.
Abstract: This paper focuses on the Mega-Sub Controlled
Structure Systems (MSCSS) performances and characteristics
regarding the new control principle contained in MSCSS subjected to
strong earthquake excitations. The adopted control scheme consists of
modulated sub-structures where the control action is achieved by
viscous dampers and sub-structure own configuration. The
elastic-plastic time history analysis under severe earthquake excitation
is analyzed base on the Finite Element Analysis Method (FEAM), and
some comparison results are also given in this paper. The result shows
that the MSCSS systems can remarkably reduce vibrations effects
more than the mega-sub structure (MSS). The study illustrates that the
improved MSCSS presents good seismic resistance ability even at 1.2g
and can absorb seismic energy in the structure, thus imply that
structural members cross section can be reduce and achieve to good
economic characteristics. Furthermore, the elasto-plastic analysis
demonstrates that the MSCSS is accurate enough regarding
international building evaluation and design codes. This paper also
shows that the elasto-plastic dynamic analysis method is a reasonable
and reliable analysis method for structures subjected to strong
earthquake excitations and that the computed results are more precise.
Abstract: In this study, shaking table tests are performed to investigate the behavior of excess pore water pressure in different soft soil-foundations of soil-structure interaction (SSI) system. The variation of the behaviors under cycled minor shock is observed. Moreover, The generation and variation mechanism of excess pore water pressure under earthquake excitation in different soft soilfoundations are analyzed and discussed.
Abstract: Antiseismic property of telecommunication equipment
is very important for the grasp of the damage and the restoration after
earthquake. Telecommunication business operators are regulating
seismic standard for their equipments. These standards are organized
to simulate the real seismic situations and usually define the minimum
value of first natural frequency of the equipments or the allowable
maximum displacement of top of the equipments relative to bottom.
Using the finite element analysis, natural frequency can be obtained
with high accuracy but the relative displacement of top of the
equipments is difficult to predict accurately using the analysis.
Furthermore, in the case of simulating the equipments with access
floor, predicting the relative displacement of top of the equipments
become more difficult.
In this study, using enormous experimental datum, an empirical
formula is suggested to forecast the relative displacement of top of the
equipments. Also it can be known that which physical quantities are
related with the relative displacement.
Abstract: Successive event of explosion earthquake and harmonic tremor recorded at Semeru volcano were analyzed to investigate the dynamical system regarding to their eruptive mechanism. The eruptive activity at Semeru volcano East Java, Indonesia is intermittent emission of ash and bombs with Strombolian style which occurred at interval of 15 to 45 minutes. The explosive eruptions accompanied by explosion earthquakes and followed by volcanic tremor which generated by continuous emission of volcanic ash. The spectral and Lyapunov exponent of successive event of explosion and harmonic tremor were analyzed. Peak frequencies of explosion earthquakes range 1.2 to 1.9 Hz and those of the harmonic tremor have peak frequency range 1.5 — 2.2 Hz. The phase space is reconstructed and evaluated based on the Lyapunov exponents. Harmonic tremors have smaller Lyapunov exponent than explosion earthquakes. It can be considerably as correlated complexity of the mechanism from the variance of spectral and fractal dimension and can be concluded that the successive event of harmonic tremor and explosions are chaotic.
Abstract: This study examines the inelastic behavior of adjacent planar reinforced concrete (R.C.) frames subjected to strong ground motions. The investigation focuses on the effects of vertical ground motion on the seismic pounding. The examined structures are modeled and analyzed by RUAUMOKO dynamic nonlinear analysis program using reliable hysteretic models for both structural members and contact elements. It is found that the vertical ground motion mildly affects the seismic response of adjacent buildings subjected to structural pounding and, for this reason, it can be ignored from the displacement and interstorey drifts assessment. However, the structural damage is moderately affected by the vertical component of earthquakes.
Abstract: This paper highlights the importance of the selection
of the building-s wall material,and the shortcomings of the most
commonly used framed structures with masonry infills .The
objective of this study is investigating the behavior of infill walls as
structural components in existing structures.Structural infill walls are
very important in structural behavior under earthquake effects.
Structural capacity under the effect of earthquake,displacement and
relative story displacement are affected by the structural irregularities
.The presence of nonstructural masonry infill walls can modify
extensively the global seismic behavior of framed buildings .The
stability and integrity of reinforced concrete frames are enhanced by
masonry infill walls. Masonry infill walls alter displacement and
base shear of the frame as well. Short columns have great
importance during earthquakes,because their failure may lead to
additional structural failures and result in total building collapse.
Consequently the effects of short columns are considered in this
study.
Abstract: Structural performance and seismic vulnerability of
masonry buildings in Algeria are investigated in this paper. Structural
classification of such buildings is carried out regarding their
structural elements. Seismicity of Algeria is briefly discussed. Then
vulnerability of masonry buildings and their failure mechanisms in
the Boumerdes earthquake (May, 2003) are examined.
Abstract: Eight steel reinforced concrete beams (SRC), were
fabricated and tested under earthquake type cyclic loading. The
effectiveness of intermediate stiffeners, such as mid-span stiffener and
plastic hinge zone stiffeners, in enhancing composite action and
ductility of SRC beams was investigated. The effectiveness of
strengthened beam-to-column (SBC) and weakened beam-to-column
(WBC) connections in enhancing beam ductility was also studied. It
was found that: (1) All the specimens possessed fairly high flexural
ductility and were found adequate for structures in high seismic zones.
(2) WBC connections induced stress concentration which caused extra
damage to concrete near the flange tapering zone. This extra damage
inhibited the flexural strength development and the ductility of the
specimens with WBC connections to some extent. (3) Specimens with
SBC connections demonstrated higher flexural strength and ductility
compared to specimens with WBC connections. (4) The intermediate
stiffeners, especially combination of plastic hinge zone stiffener and
mid span stiffeners, have an obvious effect in enhancing the ductility
of the beams with SBC connection.
Abstract: Recordings from recent earthquakes have provided evidence that ground motions in the near field of a rupturing fault differ from ordinary ground motions, as they can contain a large energy, or “directivity" pulse. This pulse can cause considerable damage during an earthquake, especially to structures with natural periods close to those of the pulse. Failures of modern engineered structures observed within the near-fault region in recent earthquakes have revealed the vulnerability of existing RC buildings against pulse-type ground motions. This may be due to the fact that these modern structures had been designed primarily using the design spectra of available standards, which have been developed using stochastic processes with relatively long duration that characterizes more distant ground motions. Many recently designed and constructed buildings may therefore require strengthening in order to perform well when subjected to near-fault ground motions. Fiber Reinforced Polymers are considered to be a viable alternative, due to their relatively easy and quick installation, low life cycle costs and zero maintenance requirements. The objective of this paper is to investigate the adequacy of Artificial Neural Networks (ANN) to determine the three dimensional dynamic response of FRP strengthened RC buildings under the near-fault ground motions. For this purpose, one ANN model is proposed to estimate the base shear force, base bending moments and roof displacement of buildings in two directions. A training set of 168 and a validation set of 21 buildings are produced from FEA analysis results of the dynamic response of RC buildings under the near-fault earthquakes. It is demonstrated that the neural network based approach is highly successful in determining the response.
Abstract: Few studies have been conducted on polymeric strip
and the behavior of soil retaining walls. This paper will present the
effect of frequency on the dynamic behavior of reinforced soil
retaining walls with polymeric strips. The frequency content
describes how the amplitude of a ground motion is distributed among
different frequencies. Since the frequency content of an earthquake
motion will strongly influence the effects of that motion, the
characterization of the motion cannot be completed without the
consideration of its frequency content. The maximum axial force of
reinforcements and horizontal displacement of the reinforced walls
are focused in this research. To clarify the dynamic behavior of
reinforced soil retaining walls with polymeric strips, a numerical
modeling using Finite Difference Method is benefited. As the results
indicate, the frequency of input base acceleration has an important
effect on the behavior of these structures. Because of resonant in the
system, where the frequency of the input dynamic load is equal to the
natural frequency of the system, the maximum horizontal
displacement and the maximum axial forces in polymeric strips is
occurred. Moreover, they were to increase the structure flexibility
because of the main advantages of polymeric strips; i.e. being simple
method of construction, having a homogeneous behavior with soils,
and possessing long durability, which are of great importance in
dynamic analysis.
Abstract: After a strong earthquake occurs, a secondary disaster due to strong aftershocks, flood, landslide or heavy snow can possible to occur and the secondary disaster due to resident-s action also can possible to happen. However, until now seldom researchers have paid attention at it. This paper focused on the Inhabitant-s action after the strong earthquake occurs when a terrible even becomes calm. An inappropriate behavior of people with disadvantaged climate after the worse earthquake can bring a tragedy to their life.
Abstract: The unanticipated brittle fracture of connection of the
steel moment resisting frame (SMRF) occurred in 1994 the Northridge
earthquake. Since then, the researches for the vulnerability of
connection of the existing SMRF and for rehabilitation of those
buildings were conducted. This paper suggests performance-based
optimal seismic retrofit technique using connection upgrade. For
optimal design, a multi-objective genetic algorithm(NSGA-II) is used.
One of the two objective functions is to minimize initial cost and
another objective function is to minimize lifetime seismic damages
cost. The optimal algorithm proposed in this paper is performed
satisfying specified performance objective based on FEMA 356. The
nonlinear static analysis is performed for structural seismic
performance evaluation. A numerical example of SAC benchmark
SMRF is provided using the performance-based optimal seismic
retrofit technique proposed in this paper
Abstract: The present work presents a method of calculating the
ductility of rectangular sections of beams considering nonlinear
behavior of concrete and steel. This calculation procedure allows us
to trace the curvature of the section according to the bending
moment, and consequently deduce ductility. It also allowed us to
study the various parameters that affect the value of the ductility. A
comparison of the effect of maximum rates of tension steel, adopted
by the codes, ACI [1], EC8 [2] and RPA [3] on the value of the
ductility was made. It was concluded that the maximum rate of steels
permitted by the ACI [1] codes and RPA [3] are almost similar in
their effect on the ductility and too high. Therefore, the ductility
mobilized in case of an earthquake is low, the inverse of code EC8
[2]. Recommendations have been made in this direction.
Abstract: Bridges are one of the main components of
transportation networks. They should be functional before and after
earthquake for emergency services. Therefore we need to assess
seismic performance of bridges under different seismic loadings.
Fragility curve is one of the popular tools in seismic evaluations. The
fragility curves are conditional probability statements, which give the
probability of a bridge reaching or exceeding a particular damage
level for a given intensity level. In this study, the seismic
performance of a two-span simply supported concrete bridge is
assessed. Due to usual lack of empirical data, the analytical fragility
curve was developed by results of the dynamic analysis of bridge
subjected to the different time histories in near-fault area.
Abstract: We board the problem of creating a seismic alert
system, based upon artificial neural networks, trained by using the
well-known back-propagation and genetic algorithms, in order to emit
the alarm for the population located into a specific city, about an
eminent earthquake greater than 4.5 Richter degrees, and avoiding
disasters and human loses. In lieu of using the propagation wave, we
employed the magnitude of the earthquake, to establish a correlation
between the recorded magnitudes from a controlled area and the city,
where we want to emit the alarm. To measure the accuracy of the
posed method, we use a database provided by CIRES, which contains
the records of 2500 quakes incoming from the State of Guerrero
and Mexico City. Particularly, we performed the proposed method to
generate an issue warning in Mexico City, employing the magnitudes
recorded in the State of Guerrero.
Abstract: In this paper, the effect of width and height of the
model on the earthquake response in the finite element method is
discussed. For this purpose an earth dam as a soil structure under
earthquake has been considered. Various dam-foundation models are
analyzed by Plaxis, a finite element package for solving geotechnical
problems. The results indicate considerable differences in the seismic
responses.
Abstract: In the present paper, active control system is used in
different heights of the building and the most effective part was
studied where the active control system is applied. The mathematical
model of the building is established in MATLAB and in order to
active control the system FLC method was used. Three different
locations of the building are chosen to apply active control system,
namely at the lowest story, the middle height of the building, and at
the highest point of the building with TMD system. The equation of
motion was written for high rise building and it was solved by statespace
method. Also passive control was used with Tuned Mass
Damper (TMD) at the top floor of the building to show the robustness
of FLC method when compared with passive control system.
Abstract: Urban disaster risks and vulnerabilities are great problems for Turkey. The annual loss of life and property through disaster in the world-s major metropolitan areas is increasing. Urban concentrations of the poor and less-informed in environmentally fragile locations suffer the impact of disaster disproportionately. Gecekondu (squatter) developments will compound the inherent risks associated with high-density environments, in appropriate technologies, and inadequate infrastructure. On the other hand, there are many geological disadvantages such as sitting on top of active tectonic plate boundaries, and why having avalanche, flood, and landslide and drought prone areas in Turkey. However, this natural formation is inevitable; the only way to survive in such a harsh geography is to be aware of importance of these natural events and to take political and physical measures. The main aim of this research is to bring up the magnitude of natural hazard risks in Izmir built-up zone, not being taken into consideration adequately. Because the dimensions of the peril are not taken seriously enough, the natural hazard risks, which are commonly well known, are not considered important or they are being forgotten after some time passes. Within this research, the magnitude of natural hazard risks for Izmir is being presented in the scope of concrete and local researches over Izmir risky areas.