جستجوی مقالات مرتبط با کلیدواژه « تحلیل دینامیکی » در نشریات گروه « عمران »

Damage to the structure during operation has always been possible, and therefore the issue of monitoring the health of important structures in order to control and manage safe operation has received attention in recent years. The process of extracting the parameters involved in identification the inherent characteristics of the target structural systems in order to monitor and detect damages is possible with different methods which have been introduced and investigated under the title of environmental modal analysis, which have been developed both in the time domain and in the frequency domain. Among the time domain methods, we can mention the stochastic subspace identification (SSI) method. The stochastic subspace identification method is one of the Output Only Modal Analysis (OOMA) methods that has been taken into consideration assuming the existence of uncertainty in modeling as well as noise in data observation and measurement, and system parameters are identification by applying statistical relationships to the output data. Due to the high accuracy of the covariance-drived stochastic subspace (SSI-cov) method which performs data monitoring by constructing the covariance function related to the recorded output data, therefore this sub-method has been used. Due to the limitation in the number of sensors that can be installed in real structures, the use of the Reference-based covariance-drived stochastic subspace identification (SSI-cov-ref) method will make it possible to identification the structure under investigation with a limited number of sensors and if there is damage, Its location can be recognized. The efficiency of the reference-based covariance-drived stochastic subspace identification method with a more limited number of sensors can also be presented. In order to damage detecting in the structure, the method of measuring changes in the modal strain energy of the members in healthy and damaged states has been used, and an index called modal strain energy has been defined and presented But in the case of damage in the structure, the undamaged members will also have strain energy due to the strain effect of the damaged members. Therefore, by using the probabilities approach, it will be possible to provide an index of the probability of structural member damage under a specific failure scenario using different information sources based on the mode shapes. In the following, using the genetic algorithm in the form of an optimization problem, the installation location for the available sensors for the target structure is optimized and presented. During the current research, after finite element modeling in MATLAB software and dynamic analysis of several samples of structure with the assumption of installing a limited number of sensors ,and the results obtained from the output of the reference-based covariance-drived stochastic subspace identification method using the changes in the modal strain energy of the members And the Bayesian strategy has been used in the damage detection in the affected members, and the efficiency of the proposed method has been discussed in the framework of the mentioned process. Based on the results obtained from the output of the proposed process, the affected members will be identified and distinguishable.
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One of the issues that affects the behavior of the structure during an earthquake is the geometrical shape of the cross section of the structure's columns. In concrete buildings, it is possible to use columns with different shapes, which can be different in terms of behavior and performance. In this research, for the analysis and design of the studied structures, two completely similar concrete buildings, one with columns with a cut surface, are compared and analyzed. circular and the other with a square cross-section under the effect of earthquake force. The results shown in the comparison of stresses and drift in two four-story buildings with circular and square columns have been analyzed by dynamic analysis, and the minimum and maximum drift and the permissible value are specified graphically. In this research, modeling of flexural concrete frame with square and circular columns under earthquake force in Etabse software and applying loads to it and performing dynamic analysis, the results were extracted from the said software and compared. The results of this research showed that the amount The energy loss of circular columns is more than that of square columns. Also, the ductility of circular columns is more than square columns, in general, the performance of circular columns in short buildings is better than square columns.

Currently, the Pardis high-speed train with a speed of 150 (km/h) is known as the only high-speed train in service in Iran. Impact factor or dynamic load allowance are the most important parameters that can express the dynamic behavior of the bridge under a train. These parameters are used in bridge design codes instead of exhaustive dynamic analyses. Although the use of impact coefficients in some cases provides conservative answers, the use of these coefficients and the possible relationships derived from them can be a good alternative to dynamic analyses due to time and computational cost savings. Masonry arch bridges are geometrically and behaviorally complex structures and it is impossible to prepare an accurate numerical model and to conduct dynamic analyses due to their multiplicity; Therefore, calculating the impact factor due to the passage of high-speed trains can determine the initial behavior of masonry arch bridges. For this purpose, in the present study, first the finite element model of two masonry arch bridges was prepared which are completely different in terms of geometric and mechanical characteristics, and then by performing 52 dynamic analyzes, the time history of impact factor and dynamic load allowance has been calculated. The results show that the behavior of masonry arch bridges is appropriate in different conditions under the Pardis high-speed train and all the calculated impact coefficients are in the rational range.

Wharf is an engineering structure which is constructed generally for loading or unloading of goods. The structure may be constructed on the weak layers like gravel and sand with respect to the bank conditions. In case of incorrect design of this type of structure and its failure, the wharf activities may be stopped for a long time due to damage to adjacent facilities. For this reason, investigating the behavior of coastal structures against failure factors such as earthquake and the liquefaction due to it, is of great importance. Analysis of wharf performance against liquefaction is done generally using the numerical methods. In this article using the Flac2D software which has the capability of nonlinear analysis of effective stress and generation of excess pore water pressure in the soil continuum, the liquefaction phenomenon in the soil surrounding the wharf is simulated using the behavioral model Finn. In continuation, the impact of different earthquake parameters on the wharf behavior is investigated. Finally, the results of the excess pore water pressure, horizontal displacement, soil settlement and bending moment of piles are presented. Then, the correlation between these parameters and different earthquake parameters is investigated. As the earthquake intensity criteria have great importance in terms of statistical assessment of seismic demand of various types of structures, therefore, in this study in order to investigate the quality of earthquake intensity criteria, the determining indices such as being optimal and applicable, efficiency index, sufficiency with respect to the earthquake magnitude and distance to the center of earthquake propagation are investigated. The results show that compatibility between the earthquake parameters and soil settlement is generally better with respect to other parameters.

Advancements in tunnelling technologies and ease of implementation of drilling methods in addition of other political and security issues made the construction of underground structures as an important alternative for answering the demands of population growth and the limitations of surface spaces in urban areas. Underground roads and highways, various types of tunnels and urban subway networks are the examples of underground structures being constructed and rapidly implemented in different countries. Meanwhile, for reducing negative effects to the environment, shortening the routes and improving traffic efficiency, urban tunnels should have high level of safety standards in design, construction and operation. Tunnels are considered major national projects and infrastructure investments, and huge costs are incurred around the world to build these structures. In countries located in highly active seismic zone, such as Iran, seismic researches for such important underground structures should not be ignored. The safety of such structures should be provided with respect to all loading demands and hazards issues associated with the site, including seismic loads. Reviewing seismic events in the past shows that underground structures have suffered less damage than above ground structures against seismic loads. However, in recent years, major earthquakes such as the 1995 Kobe earthquake in Japan, the 1999 Chi-Chi earthquake in Taiwan, the 1999 Kocaeli earthquake in Turkey, and the 2008 Wenchuan earthquake in China have caused underground structures to experience significant damage. There is evidence to conclude that the structural vulnerability of a tunnel in seismically active areas is an important issue but is either not yet well understood or not well assessed at the time of construction, emphasising that dynamic analysis of these structures against seismic loads is necessary. Earthquakes are likely to significantly affect tunnel performance by causing severe damage or excessive deformation of the tunnel structure. To understand the seismic-induced behaviour and performance of urban tunnels, this paper provides the state of the art in modelling studies of seismic design and assessment of tunnels. The review includes an investigation in seismic responses of real tunnels reported during past seismic events, the probable mechanisms caused damages in tunnels and physical and numerical methods used until now to either investigate those mechanisms or implemented in new designs. As an introduction, the seismic performance of tunnels affected by previous seismic events discusses first, emphasising the effective parameters in evaluation of tunnel seismic response and the relationship between the parameters, and the damage levels caused during earthquakes. Subsequently, the paper continues with a comprehensive literature review on the experimental methods used to investigate seismic-induced response in tunnels including physical testing, centrifuge tests, shaking table tests, and static tests. Analytical, quasi-static and numerical methods of dynamic analysis of tunnels and the accuracy of these methods are discussed then in details referring to some examples. The paper also reviews the effects of soil heterogeneity in the seismic response of tunnel and application of the random field for dynamic analysis of underground structures.  Examining the achievements and challenges remained in the field, the paper concludes with the existing gaps in the field to stimulate readers for doing more relevant researches.

Most seismic hazard assessments are usually performed only with consideration of the initial shock in the technical literature of structural and earthquake engineering. While the magnitude of aftershocks that occur after the main earthquake, may be enough strong to cause a lot of damage to the structures. Most aftershocks increase the structural damage caused by the main earthquake because of cumulative damage and increased vulnerability may seriously threaten the safety of residents. The structures are designed for solely a single earthquake – design earthquake –  based on the existing seismic design codes. For example, these codes did not provide specific values for the actual relative displacement under successive earthquakes to assess the structural damages. Therefore, considering the effect of multiple shocks consist of fore-shock and main-shock or main-shock and after-shock seems necessary. Moreover, the construction of a new building is not economic and requires a lot of time, which is not easily available to many communities. Hence, the design of structures considering the some capabilities such as replacement of damaged elements can improved significantly the performance of structures after severe successive earthquakes. However, most of the proposed structural systems are not generally repairable while replacing several damaged members under the earthquake, can be very economic and applicable. The linked column frame (LCF) as a relatively modern lateral bearing system, is a type of dual systems; the recent emergence of this structural system has reinforced the need for multiple seismic studies. For this reason, LCF is selected in this paper and the deflection amplification factor (Cd) for this system is evaluated under critical earthquakes with seismic sequences. This coefficient is calculated based on the linear displacements obtained from linear static analysis and actual values from nonlinear analysis. In this regard, 18 steel frames equipped by the linked column frame as lateral bearing system, with 3, 7, and 11 stories are designed based on the Iranian earthquake design code (Standard No. 2800, 4th version – 2014). These frames are implemented in Opensees software and have been subjected to linear static, linear, and nonlinear dynamic analyses using critical earthquakes with/ without seismic sequence phenomenon to calculate the deflection amplification factor (Cd) and Cd/R for each of them based on Uang methaod. In order to better investigation of the mentioned coefficient, the effect of various parameters such as the length of the connection beams as well as the flexural or shear behavior of the connection beams have been considered. Thus, after the evaluations, the findings indicate an increase in Cd and Cd / R values, for the linked column frame with the connected column exposed to successive earthquakes. The increase of this coefficient has been more in short-frame frames. So that the most increase which hase been related to the 3-story frame with shear behavior and 2-meter linked distance, is about 11 percentage under the successive earthquakes. Also, the average results which have been obtained from consecutive earthquakes reveal that the proposed values ​​for Cd coefficient in the technical literature are not sufficient, and larger values ​​have been demanded.

Earthen dams have a significant impact on the lives of surrounding communities, so the need for continuous monitoring during the construction and safe operation of these structures when applying dynamic loads, especially explosive loads due to possible sabotage and firefighting has always been considered. The effects of explosive loading, assuming the conditions affecting the performance of earth dams, can be measured using several parameters, the most important of which are the dimensions of the pit caused by the explosion and the stability coefficient of the slopes of the structure. Therefore, in the present study, according to the researches done in the field of dynamic loading of earth dams, while selecting the model and its characteristics, in order to validate the simulation process and apply dynamic loading, the results of numerical solution with the article A reference is compared that provides acceptable consistency. Then the dynamic loading of the explosion in the form of finite element software is simulated in certain parts of the structure and after analysis, the results show that by increasing the explosive charge and increasing the water level of the dam reservoir and also reducing the density of constituents Of the body; The depth and dimensions of the hole created by the explosion in the crown of the dam will increase, which will also indicate local damage. Finally, to investigate the dynamic stability of the slopes, the results are transferred from finite element software to the slope stability analysis software, and the model under pseudo-analysis Static and dynamic, and finally stability analysis. The results indicate that under an explosive charge of 800 kg , the reliability coefficient of slope stability is higher than the reliability coefficient introduced by the publication 624, which indicates no serious damage and instability of the dam structure

One of the most widely used among the existing methods proposed by the codes for the seismic analysis of structures is linear static analysis. Several methods have been presented for determining the static lateral load pattern. In spite of the simplicity of the existing procedures, their accuracy is not desirable, especially for structures in which the influences of higher modes are significant. In this study, a new method is developed to improve the lateral load pattern in linear static analysis. To achieve the proposed lateral load distribution, firstly, the average response of structure subjected to some earthquakes is acquired. Then, regarding the dynamic of structures, the static lateral load pattern compatible with the average response is developed. Eventually, to derive a straightforward and hands on lateral load distribution, using a statistical study, some relations coupled with a graph are developed. Since the proposed method is developed based on the structural responses resulting from linear dynamic analysis (time-history analysis), it is shown that the suggested way despite its simplicity and efficiency, presents appropriate accuracy in predicting the response of the structures subjected to seismic excitations. The developed method is evaluated for a set of structures with different fundamental periods. Results show that the method gives higher accuracy in comparison with the static method of Iranian standard 2800 and FEMA 356. Also the developed procedure can be considered as an appropriate technique for determining lateral load distribution in seismic codes.

Analysis of underground structures under blast has challenges due to the complexity of blast dynamic loading and soil behavior. Due to the role of underground structures as a shelter and the vulnerability of these structures to explosive loads, it is vital to investigate and analyze the effect of explosions on these structures. The aim of this study is to investigate the effect of explosive projectile distance from the underground structure and the diameter of the explosive sphere on the underground structure. For this purpose, using the finite difference method and dynamic analysis, the underground structure was simulated for different distances of the explosive projectile and different diameters of the explosive sphere. In this study, the propagation of explosion waves in a spherical manner was considered by applying an explosion pressure on the wall of the explosive sphere. The results show that with increasing the distance of the underground structure from the center of the explosion, the maximum soil pressure on the maintenance system as well as the bending moment and axial force in the canopy and wall of the tunnel maintenance structure decrease exponentially. In addition, after the explosion wave reaches the tunnel maintenance system, the displacement and vertical velocity of the storage system particles in the tunnel crown is the highest. As the diameter of the explosive sphere increases, the bending moment at the crown and wall of the tunnel increases almost linearly, which is three times the slope for the tunnel crown

Considering the high seismic potential in most parts of Iran, the importance of studying the behavior of earth dams under earthquake loading, especially in the southern regions, is very important due to the number of these dams and seismicity of the Zagros mountain range. In recent years, many studies have been performed on the effects of earthquakes on earth dams, but these structures exhibit seismic response and different dynamic behavior in earthquakes under different geometric conditions and properties of different materials.In this study, the Shamil earth dam located in Hormozgan province has been investigated due to the importance of its application by means of numerical methods using the critical linear equation method. Dynamic behavior and seismic response of the dam and its following in terms of strains, tensions, acceleration and displacement distribution have been studied and the areas which susceptible to fracture were identified based on the relevant criteria. The results show that the upper part of the dam has a potential to crack and the maximum displacement is very small and occurred in less than one percent of the height of the dam, which indicates the stability of the dam during and after earthquakes.

Abrupt and non-uniform changes in track vertical stiffness in railway bridges transition zone, increase dynamic loads, asymmetric deformations and track components damage and as a result, it increases maintenance costs. In this paper, the most widely used methods for stiffness transition are investigated, including concrete approach slab, hot mixed asphalt layer, stabilization and improvement of transition zone embankment. Then, the innovative combinatorial methods including improvement of transition zone backfill (embankment) materials with resilient pads under sleepers and rails on the deck based on specific criteria according to the finite element model. The results show that despeite various stiffness transition methods, the track according to the rail vertical displacement, ballasted layer vertical displacement and stress in the middle of the subgrade layer states has more desirable behaviour by about 14 to 22 percent, 3 to 29 and 4 to 36 percent respectively, rather than there is no stiffness transition in transition zone. Based on dynamic analysis, rail dynamic vertical displacement, rail dynamic vertical acceleration and force in subgrade layer is decreased by about 11 to 17, 32 to 40 and 1 to 22 percent respectively. Finally it appears that a combinatorial transition method include improved embankment in transition zone with resilient pads under the rail for rail on deck improved track behavior based on the criteria the rail vertical displacement and ballasted layer vertical displacement about %31, also decreased the normal stress in the middle of the subgrade layer approximately %28 and based on dynamic analysis, rail dynamic vertical displacement, rail dynamic vertical acceleration and force in subgrade layer is decreased by about 21, 34 and 23 percent, respectively. This method can provide the best impact and performance between different methods for concrete short span bridge and the relative displacement reduced in transition zone from 0.55 mm to 0.11 mm.

In the present paper, the effect of rotation with different angles in the Structural bearing system was investigated by irregular non-parallel systems in the concrete structure with the dual design bearing system of the moment frame and the concrete shear wall. The structure was examined in two different modes, first without rotation in the bearing system and analyzed at an angle of zero degrees. Then, the bearing system was seismically analysed by rotating at angles of 15, 30, and 45 degrees to create irregularities in non-parallel systems. The results of structural behavior were performed by comparing the values of base shear, drift, and torsion effect in the structure. The results of the present study showed that the amount of drift and base shear of the structure in the state that has irregularity of non-parallel systems in the structure is more than the state of the structure without irregularity of the non-parallel system. Comparing the amount of base shear for the angels and other modes increases the amount of base shear by increasing the rotation angle of the bearing system, which increases the amount of rotation angle, imposes more force on the structure. The amount of base shear for the angle of 30 degrees of rotation of the Structural bearing system in the main direction of the building is more than other angles. The analysis results also showed that the non-parallelism of the central core of the structure reduces the lateral bearing capacity of the whole system. As a general conclusion, it can be stated that the higher the rotation angle of the bearing system, the higher the amount of displacement and drift, which is the most critical state for the 30-degree angle and the best performance in the structure for the zero degrees angle.

The dynamic design of tunnels and their dynamic response under various seismic and vibration loads is one of the important in tunnel engineering issues that has been studied by researchers in recent years. The most suitable methods for investigating the effects of seismic and vibrational loads on tunnels and underground structures are analytical methods and numerical simulations. In numerical methods such as finite element method or boundary element method, the problem is first modeled and then analyzed. Comparing the results of research in this field, it can be concluded that due to the low flexibility of analytical methods in solving problems with geometry and properties of complex materials, the need to use numerical methods is more felt because of its advantages in solving complex problems. The purpose of this study was to investigate the review for effect of vibrations on tunnels and underground structures that is special considered at design.

In structural dynamic analysis, various time integration techniques have been proposed. Generally, these algorithms discretize the time domain into a finite number of intervals and approximate the displacements, velocities, and accelerations via mathematical expressions at each time increment. Based on the structure of these approximations, time integration schemes are classified as explicit and implicit. Explicit schemes are much simpler and often march forward only through pure vector operations. On the other hand, implicit strategies require more computational efforts especially in nonlinear behaviors since they involve solving a system of simultaneous equations at each time step using iterative techniques. Although computationally more expensive, implicit schemes are unconditionally stable, meaning that the growth of solution errors at each time increment remains bounded. On the contrary, explicit techniques suffer from instabilities which manifest as unrealistic growth of amplitude of the responses. To overcome this issue, time step size should be chosen small enough to meet the stability criterion. In this paper, by gathering the advantages of both approach, a new semi-explicit unconditionally stable time integration method based on the well-known implicit Generalized-α (G-α) technique is proposed. To this end, first, the fundamental approximating relationships of the suggested method is introduced for a single degree of freedom system with the unknown integration parameters. Then, using the concept of amplification matrix, these unknown parameters are determined so that the method possesses the same characteristic equation as the G-α technique. This leads to a set of model-dependent integration parameters that are no longer scalar constants. Due to this kind of formulation, similar stability and accuracy behavior are observed when comparing the proposed method with the G-α technique, both analytically and numerically. After generalization of the proposed algorithm to the multi-degree of freedom systems, some numerical examples are solved and comparisons are also made with other similar time integration schemes. Findings reveal the merits of the proposed algorithm over the other well-known time stepping techniques.

Gravity block type quay walls are one of the main options when the seabed has a suitable bearing capacity. Today, the design of quay walls is based on its seismic performance, and the pseudo-static method is the most common design method. In this method, the force caused by the earthquake is considered as the product of the equivalent acceleration coefficient in the effective mass of the structure. The choice of the value of this coefficient, consisting of horizontal (kh) and vertical (kv) components, is of great importance. Therefore, in this paper, the effect of selecting the earthquake equivalent acceleration coefficient on the seismic performance of the hunch-back quay wall of Pars Petrochemical Port has been studied as a case study. In this regard, the recommendations and relationships reflected in the old and new editions of the Japanese Maritime Codes (OCDI, 2002, 2009) are more comprehensive and complete than other codes, especially in the seismic design of berths. The results illustrated that the proposed relationships of horizontal earthquake acceleration coefficient (kh) based on the new version of the Japanese code is more suitable and helps predict the seismic performance of this type of quay walls more accurately and their realistic design. Moreover, in this research, based on acceleration time-histories resulted from seismic hazard studies at the site, using FLAC2D software, the values of horizontal displacement of the quay wall crown have been investigated, and based on that, earthquake coefficient values have been predicted for each relevant time-history.

Concrete faced rockfill dams (CFRDs) are among the structures that due to their advantages such ease of construction and low execution costs,have attracted more attention nowadays.Due to the fact that during large earthquakes,the hydrodynamic pressure will be large and cannot be ignored,the main purpose of this research is to apply reservoir hydrodynamic pressure of dam reservoir caused by the earthquake and investigate its effects in three-dimensional analysis using ABAQUS software.The considered dams in this study have 70,100&130 meters height located in the valley with the length to height ratio of  (L/H=1)&(L/H=3). To investigate the effect of the earthquake,a maximum scaled acceleration of 0.6g was used in the carried out analysis.Linear elastoplastic Mohr-Coulomb material model for rockfill embankment, an elastic material model for rocky foundation,and the concrete damage plasticity model for the concrete face are adopted.In order to take into account,the effects of the reservoir hydrodynamic pressure,the reservoir water is represented by acoustic elements with the Lagrangian formulation.It is found that considering the hydrodynamic pressure, increases the settling values by 5to80%,plastic strain by 37%, surface compressive stress by 20to57% and maximum dam crest acceleration up to 2 times in some of the analyzed dams.

Developing transportation system in populated cities needs to construct subsurface infrastructures, such as tunnels. With a close attention to densely surface structured urban environments, it is most likely that tunnels would inevitably cross near of adjacent structures. It should be considered, whether the settlement induced by tunneling are in allowable range or not. Several factors may affect the magnitude of ground movement due to tunneling and consequently the tunnel- structure interaction, such as ground geotechnical properties, adjacent structure stiffness and relative position of structures and tunnels, and tunnel construction parameters.When pile foundations are exposed to intense dynamic transverse loads during earthquakes, soil- structure interaction (SSI) plays an important role in allocating the response of pile foundations to lateral excitation. The numerical investigation with analysis subway tunnels and deep foundation interaction behavior under seismic loads by the finite element method was carried out.

In seismic analysis, vertical component of the earthquake due to the impact on fluid sloshing in a tank and intensifying of "P-delta" effects is of particular importance. In order to investigate the performance of the tank and the impact of the fluid surface sloshing, harmonic frequencies were applied to a tank of of water with 60 cm in diameter and different depths of water. Different frequencies were applied to the tank by an innovative tool. Abacous is a structural soft-ware which is capable to model numerically the interaction of structure and fluid. Verification and calibration of numerical model was performed by comparing water level fluctuations in experimental and numerical models. Different combinations of parameters such as hourglass coefficient, methods of grid generations and the cell sizes in numerical model were performed to obtain the consistent results with experiments. The results of numerical modeling had a correlation factor of 98% with laboratory results. Then, the numerical model of elevated tanks with large scales were created in software The numerical model of elevated tanks with three different ratios of fluid depth and tank radiuses to the tank height were created and modeled by software. The angle of the floor in all tanks was 45 degrees. Each case was evaluated by7 different mapping acceleration from different earthquakes. In all cases the effect of vertical component of earthquake, the wave height and moment in foundation were investigated. The results showed that the vertical component of the earthquake resulted in an increase of 38% in the height of water and 9% increase in the moment of foundation.

In this study, dynamic behavior of earth dams with clay core was analyzed using finite element method. The seismic responses of earth dams under main and wavelet-based decomposed earthquake records were investigated. Earthquake records were decomposed up to five stages by using wavelet de-noising method. The ratio of acceleration response spectrum to maximum acceleration, ratio of velocity response spectrum to maximum velocity, ratio of displacement response spectrum to maximum displacement, Fourier amplitude spectrum and time history of Arias intensity of earth dam crest under main and wavelet-based decomposed earthquake records were analyzed. The results demonstrate that the acceleration response spectrum ratio of dam crest under de-noised records up to 3rd level and the velocity and displacement spectrum ratios of dam crest up to 4th level has an acceptable accuracy in comparison to the responses under main earthquake records. Results of dynamic analysis indicate that Fourier Amplitude Spectra and Arias intensity of earth dam crest under de-noising based records up to 4th level are compatible with main earthquake records. The results indicate that the wavelet-based decomposed earthquake records can be a reliable alternative for main earthquake records in dynamic analysis of embankment dams.

In this paper, the damage detection of single tapered pole is studied. Structural damage has been identified using the vibration method. In this method, the APSO was used to detect the location and severity of the damage. The objective function for detecting damages, is a correlation coefficient based on natural frequencies. In order to accelerate the calculation of the natural frequencies of the structure, iterative method was used. In this paper, the damage is applied to the structure, by reduction of the stiffness matrix of the element in a finite element modeling and also in order to match the real situation, error in frequency is considered. To evaluate the efficiency and robustness of the proposed method in detecting damage of tapered poles, two numerical examples, including a police surveillance camera pole and a water storage pole under different damaged scenarios, are examined. In first and second example, structures are divided by 15 and 25 elements, respectively, with uniform moment of inertia. The results show that the proposed method is capable of detecting both location and severity of the damage properly, despite the complexity of some damage scenarios. Therefore, the algorithm can be used to detect the damage of other structures.