BULLETIN OF EARTHQUAKE SCIENCE AND ENGINEERING
Year:2020 | Volume:7 | Issue:2|Papers Count:13

Within the past few decades, researchers and designers have become more interested in utilizing the hybrid structures consisting of the reinforced concrete and steel members. This combined system benefits its own advantages from both steel and concrete characteristics. One of these systems is the RCS; Reinforced Concrete Column Steel beam. A moment frame consists of Reinforced Concrete columns (RC) and Steel beams (S). In this research, two samples of this type of connection whose experimental models were established by Alizadeh et al. (2000) were used. Both specimens were tested under quasi-static reversed cyclic loading and simulated using a nonlinear three-dimensional finite element method analyzed by the ABAQUS software. After verifying the FEM models, some special joint details were simulated for investigating the effect and the performance of the steel band plates, FBPs, EBPs, WFBPs, ABPs, steel doubler plates and the stirrups in joint. Lateral load story drift response, the cracking pattern of the joints, shear strains at the joints, non-linearization of steel beam were studied in the considered models. The results indicated that the performance of the models depended directly on the joint detailings, the effectiveness of the shear keys, and the amount of the confinement provided for the panel zone region. Engineered cementitious composites (ECC) are a class of high-performance fiber reinforced cement composite with strain hardening and multiple cracking properties. Therefore, replacing the connection column with strong and flexible concrete, such as engineered concrete, increases the seismic behavior of this type of connections. Therefore, composite concrete was replaced by the column concrete in the modeled joints for further investigations. The comparative results indicated that the application of the ECC in columns, beam-column joints, in parts or as a whole, in composite systems can greatly improve their seismic behavior. In addition, the use of ECC, allowed the reduction and even the elimination of the steel transverse reinforcements in the connection. This indeed simplifies the joint detailing, especially when the beams are framing into the same column from different directions. Finally, a model of RCS connection with ECC is presented, which in addition to simpler detailing scheme in the joint area, has also a favorable seismic behavior.

Automatic seismic phase picking algorithms are one of the current research topics and have special significance in seismic data processing requirements. One of the most fundamental tasks in seismology is the identification arrival time of seismic phases such as the compressional or P-wave, transversal or S-wave, Rayleigh-wave, Love-wave, reflected and refracted wave from boundary layers must be identified. Seismic phase arrival time identification enables scientists to derive important geophysical and seismological information, such as the geotectonic settings, structure of the earth’ s interior, seismicity of an area and seismic hazard assessment. Traditionally, these quantities were measured manually by human experts, but as seismic networks have grown worldwide, such tasks have been increasingly taken up by automated algorithms. because seismic network or even a single station operating continuously at high sampling frequency produces an enormous amount of data, processing of such a volume of waveforms manually is very time-consuming and requires considerable manpower. In addition, due to human error, incorrect detection of the phase can affect future studies. Therefore, it is needed to an alternative more efficient, faster, and accurate method that reduces the human, financial and time costs and also decreases the probability of errors. Hence, in recent decades, significant efforts have been made to develop automatic phase picking methods. Wavelet transform is a tool in the analysis of nonstationary signals such as the seismic signal. This is due to the ability of the wavelet transform to resolve features at various scales [1]. In particular, there are two types of wavelet transforms, orthogonal as discrete wavelet transform (DWT) and non-orthogonal as maximal overlap discrete wavelet transform (MODWT). DWT is useful in decomposing time series data into an orthogonal set of components with different frequencies. Whereas MODWT is a variant of DWT that can handle any sample size. The smooth and detail coefficients of MODWT multiresolution analysis are associated with zero phase filters and produces a more asymptotically efficient wavelet variance estimator than the DWT [2]. Working in the wavelet domain allows multiresolution analysis of the waveform, and provides the means to distinguish the phase arrival from random or systematic noise. In this work, we take advantage of the wavelet transform properties and define characteristic functions to detect P-and S-wave arrivals. The version of the maximum overlap discrete wavelet transform (MODWT) is used to determine and picking the arrival time of the P and S phases. The methodology of this study is divided into two parts: the first part is about the determination of the P arrival time obtained by processing the stacked envelop of the wavelet transform coefficients. The second part is determining the S arrival time, the automatic S-phase detection algorithm that we present in this paper is a combination of wavelet transform (WT) and AR model. The estimation of arrival time of the S wave is done in two steps. At first, an initial estimation of arrival time is calculated using the MODWT transform. In the next step, the final estimation of the S wave arrival time is calculated using an AR model. Method is tested on a significant number of Kermanshah cluster earthquakes. The results of automatic phase picker algorithm in this study have been compared with the STA/LTA method to assess the accuracy.

Observations after the 1999 Turkey and Taiwan earthquakes and the 2008 China earthquake have indicated that the structures experience different levels of damages induced by faulting dislocation. Numerous studies have been conducted on the most common types of foundations such as shallow foundations, pile and caisson foundations subjected to faulting by means of numerical and experimental investigations. The parameters affecting the interaction of a reverse fault rupture with a shallow embedded foundation have been investigated by experimentally validated numerical models using ABAQUS software. These parameters are the embedment depth of foundation, the bearing pressure of foundation, the rigidity of foundation and the foundation position. The reverse fault rupture at a dip angle of 60° propagates in a moderately dense sand layer and interplays with the embedded foundation. A summary of conclusions is as follows:  The behavior of foundation and the development of rupture mechanisms are fully dependent on the location of the foundation relative to the fault rupture and the magnitude of the fault offset. Depending on the foundation position, the loss of support of the foundation takes place either under the edges (i. e. the hogging deformation) or under the middle (i. e. the sagging deformation) of the foundation. The foundation experiences the loss of support and stressing even for the indirect-hit case when the fault rupture emerges outside the foundation width.  The increase of the weight of the foundation leads to diverting the fault rupture and less stressing of the foundation. However, the rotation of foundation depends strongly on the foundation position relative to the fault outcrop compared to the weight of the foundation. By increasing the embedment depth of the foundation, the weight of the foundation has no beneficial effect for the behavior of shallow foundation and the kinematic constraint of deeper foundation causes to significantly increase the rotation of the embedded foundations.  As the embedment depth increases, the rotation of the foundation decreases for the same rupturing mechanism. It can be attributed to the similar performance of a deeper shallow embedded foundation to that of a deep foundation (such as a caisson foundation). However, the rotation of the foundations with the different embedment depths is largely dependent on the position of the foundation relative to the outcropping fault rupture and the magnitude of the fault offset. Also, the results show that the different fault-induced mechanisms such as footwall, gapping and hanging wall may happen depending on the magnitude of fault offset for a given embedment depth and position of the foundation.  Depending on the rigidity of the foundation, the rigid shallow foundation may diffuse/divert the fault rupture beyond the foundation, whereas by contrast with a flexible foundation, the fault rupture will develop as a distinct rupture and strike the foundation underneath. In all cases, the foundation rigidity is an important parameter controlling the stressing of the foundation. Decreasing the rigidity of the foundation causes to increase the normalized bending moment of the foundation and the foundation may experience substantial distress. The results indicate that rigid shallow foundations are more suitable than flexible ones for a structure subjected to a major reverse fault rupturing underneath.

The retaining wall is a wall that creates a lateral support for vertically or vertically oriented walls for the soil. Simplicity of construction and ease of use are the features of the use of gravity retaining walls. The prediction of the displacement and rotation caused by the earthquake is an important point in the seismic design of the gravity retaining walls. Excessive displacement does not only damage the walls itself, but also causes irreparable damage to adjacent retaining walls. The forces imposed on the wall by the earthquake depend on factors such as the behavior of the soil under the wall, the behavior of the embankment, the flexural behavior and the wall's inertia, and the nature of the entrance movements. One of the techniques for wall design is a power-based method and a performance-based method. In this paper, using the ABAQUS / CAE finite element software, the seismic performance of the gravity retaining wall is evaluated under harmonic load. Four types of subsoil according with the 2800 regulations and three types of backfill (sand behind the wall) are used. Two types of wall are 3 and 6 meters under sinusoidal load at the fundamental frequency of each model and the effect of backfill, subsoil and height of the wall on the top displacement, bottom displacement and rotation were investigated. The results of this research show that as the soil around the wall is denser, the wall displacement decreases. The amount of displacement increases with increasing wall height. The higher the density of the soil in the site, the lower the maximum vertical stress on the wall. By changing the soil profile and increasing soil bed density, the mean value of the average maximum absorbed acceleration increases. Mechanical properties of the embankment such as density, internal friction and hardness, effect on the average maximum acceleration and maximum vertical stress. With increasing dynamic loading; the average maximum acceleration is increased. Under the basic vibration of the wall, the height and dimensions do not have any effect in maximum absorbed acceleration. By increasing the wall height, the vertical stress decreases. The result of this research show that dimension and physical characteristics of retaining wall and soil properties of embankment have effect on absorbed maximum acceleration and the maximum vertical wall stress in different conditions of seismic acceleration by numerical method. The numerical models were analyzed for sinusoidal harmonic loading at the fundamental frequency of the model (natural frequency of the first mode). The results of this research are summarized as follows.  By increasing the wall height, the vertical stresses generated in the model are reduced. The increase in wall height does not have a significant effect on the average maximum absorbed acceleration.  With increasing soil density around the wall (backfill and foundation) due to the increased hardness of the soil, the wall shows a good resistance to the forces involved and creates a lower stress in the wall.  increasing the density of soil around the wall (backfill and foundation), followed by increasing density and hardness, the average maximum acceleration absorbed by the part of the backfill that is in contact with the back of the wall increases.

In seismic design of engineering structures, usually bedrock acceleration-displacement response spectra are within hand. The crucial issue in seismic design of underground structures is the serious need for the geotechnical logs to be used in numerical simulations. However, large dimensions of typical sub-surface structures like tunnels, subways and sewage water transporting routes, require considerable logging efforts based on notable budgets. As such structures would lay several ten meters under the ground surface, the mentioned efforts and budgets expand with respect to that of required for over ground systems. Hence, any approximate estimation on critical bedrock depth can help to draw reasonable engineering design judgments. Providing such information, regardless of precise log information, guide the designer to implement conservative assumptions and reach upper bound estimations on seismic demands. To approach this goal, here, an investigation is conducted to find such critical depth parametrically. The structures are considered as box shaped long embedded systems for which 2D rectangular cross sections are studied linearly and a simple procedure for fast and conservative seismic design is proposed. To this end, the article constitutes of two parts. At first, the approximate relation between maximum bedrock displacement (DB) and maximum internal drift of the soil layer over the bedrock (DL) is explored. It is notable that in underground soil-structure interaction, the soil deformation field surrounds the structure and through an interaction procedure, both soil and structure converge to an equilibrium state. So, maximum internal deformation of the soil layer, in which the structure is embedded, plays an important role in seismic demands of subsurface struc tures. In this part, a set of 20 real bedrock records is utilized to reach the approximate DB-DL relation through a linear wellknown closed form equation for single layer transfer function. The bedrock histories were all selected from the sites with shear wave velocity, Vs, over 700 m/s. The results of this part show that the average value of DL, for the selected set of records, is approximately close to the value of DB. In the second part, various Finite Element (FE) models were developed in ABAQUS software including different structures. Then, the resulted DL from previous step was applied to the boundaries of FE models, in first-mode-shape of each layer. It is supposed that the total layer deformation comes from its first mode shape. Next, the uppermost flexural, shear and axial strains are tabulated and sketched against the parameter H/Vs, where H is the soil layer depth. This process was repeated for structures with different values of flexibility ratio, FR, and aspect ratio, AS. The effect of h/H ratio is also reviewed where h is the structure vertical dimension. The depth of the structure from ground surface is set to a constant value and just a single layer over the bedrock is taken into account. The trends of strain demands and critical layer depths are the explored and discussed. It is shown that, as the distant of the structure and the bedrock diminishes, the strain demands increase. This happens as the maximum gradient of soil deformation occurs near the bedrock surface. This makes clear that, in the absence of enough information on soil layers, it is suggested that the minimum stratum laye5r depth to be considered for a conservative analysis. Such depth, which can be assumed as the overburden depth plus structural vertical height, is expected to produce the upper most seismic demands for preliminary design of underground structures. It should be noted that this research is based on linear analysis and complementary investigations, considering different types of nonlinearities, are required to reach more precise conclusions with more reasonable safety factors.

According to increasing demand of box-shaped tunnels in transportation networks, which are mainly built as cut and cover tunnels, the impact of natural hazards such as earthquakes on these geotechnical structures and seismic load reduction methods of these types of structures is more important than before. Nowadays, the use of lightweight materials such as geofoam plays fundamental role in civil engineering and has solved many of the challenges of civil engineering. In the present study, the role of geofoam materials as embankments for cut and cover tunnels on the internal forces of the tunnel structure during the earthquake have been investigated. The numerical modeling was performed by twodimensional finite difference software, FLAC 2D v7. 0. The results of an experimental study were used to verify the numerical model. Time histories of acceleration and bending moments for Kobe and Northridge earthquakes were examined. Based on the analysis, it was observed that the software was able to predict the results of the centrifugal experiment well and provided reliable results. EPS19 has been used as a geofoam embankment in the analyzes. The acceleration time history of the Kobe and Northridge earthquakes with a maximum acceleration of 0. 3 g has been used in the analysis. In the numerical model of the present study, the equivalent linear model (ELM) has been used to model the behavior of the geofoam. MohrCoulomb elastoplastic model was used in soil behavior modeling for static analysis. The behavior of the soil in dynamic analyses was considered as nonlinear and modeled with hysteretic damping. The results are determined in the form of bending moment and shear force diagrams for the roof and wall of the tunnel. The diagrams were provided for static and seismic loading conditions. According to the results of numerical studies, it was observed that the geofoam model has a very good performance in reducing the bending moments and shear forces in static and seismic conditions. Present study shows that geofoam, as the cover material of the cut and cover tunnel, is able to reduce internal forces of the tunnel structure in static, seismic loading condition compared to the soil. Based on the results, it was concluded that geofoam is a suitable material for retrofitting the cut and cover tunnels during earthquakes.

Source, site and path effect are three important parameters in ground seismic response in any area (flat surface and sloping surface). Site effect is a key parameter to study the evaluation of the seismic response of a hill or valley particularly in soil. Another important parameter is the soil layer combination in height of a hill, for example. In other words, appearing a loose and weak layer between dense soil layers, makes different seismic responses in comparison with a full homogenous slope in height. As we know in nature, there is not full homogenous slope or hill, so it is very important to study this problem in evaluating ground seismic response. We should take part soil slopes and rock slopes in seismic analyses. In this research, only non-homogenous soil hill is studied. We know that the slope angle has a clear role on the hill seismic response, so the amplification can be seen in top of the hill. It is clear that gathering energy in a bounded local area, top of the hill, can make a great response at top of the hill, as we call it, amplification. Amplification is related to different parameters such as soil layer parameters, geometry, slope angle, wave type and its characteristic as dominant frequency, and maybe so many other parameters that researchers have not studied yet. Another important civil engineering problem is construction on top of the slopes or near them. Therefore, in high seismic disaster areas, we may have large demolition of structures if designer has not implemented the site effect on his/her analysis. Recently, in 2800 Code (4th edition), topography effect is implemented in a simple table due to the slope angle to increase horizontal acceleration parameter. It should be noted that other different parameters may have great effect on ground seismic response and slope angle is one of them. In this research, effects of non-homogenous slopes’ angle on seismic response of ground surface due to the incident SV wave using FLAC 2D finite difference software are studied. Different parameters are used in this research. The numerical and behavioral model linear elastic is selected. In order to study the effect of non-homogenous slopes, slopes with different materials with 25, 30, 35, 45 and 60 degree are selected. In addition, dependence of slope angle with other slope height and incident wave frequency are studied. Obtained results show that the effect of slope angle on seismic response, in comparison with other studied parameters, are low and it may be neglected. Besides, it can be seen that changing the location of soil layers, does not have high effect on ground seismic response. The results show that the effects of slope angle in low frequencies and also low height are small on ground seismic response. Thus, increasing these parameters, frequencies and slope height, increases the effect of slope angle on ground seismic response. In this research, due to dependence of slope angle to slope height and incident wave frequency on ground seismic response, the effect of slope angle on amplification of non-homogenous slopes are studied based on different H/  (normalized height). In H / 0. 4   , the effect of slope angle on amplification response can be neglected. In other words in this condition the effect of slope angle is small but increasing H/  , increase this effect. For H / 0. 4   the amplification response in slopes with 25 degree is the highest in comparison with 30-degree slope. In addition, these results can be seen in 30-degree slope in comparison with 35-degree slope.

Infill panel significantly affect the behavior of surrounding frame. The infill walls are usually considered as nonstructural element in analysis and designing process of the structures which is due to inherent complexity and uncertainty behavior of the infill wall and its materials. However, the seismic codes and guidelines are recommended to consider the effect of infill walls on strength and stiffness of the frame structures by using some simple macro models as well as changing the fundamental period of the structures. Among many model proposed by researchers in the literatures, the equivalent diagonal compression strut model is more prevalent, which is recommended by seismic guideline codes. Due to dead and live loads, the presence of vertical loads applied on the beams and columns of the frames is unavoidable. Moreover, the rigidity of beam to column connections of the frame is different and changed depending on the connection types. The previous studies have shown that the presence of vertical load on the frame or the rigidity of frame joints affect the behavior of infilled frames. However, these effects are not considered to estimate the mechanical and geometric characteristics of equivalent strut in seismic codes. In other words, the previous researches have not presented an obvious and explicit conclusion to take into account the vertical load and connection rigidity effect on the modeling of equivalent strut. Moreover, it is assumed that the equivalent strut of multi-bay infilled frame have the same characteristics of that in single-bay ones, which is doubtful based on results of previous researches in the literature. In this paper, the effect of vertical load, connection rigidity and number of bays on the seismic lateral behavior of infilled frames are investigated. For this purpose, an experimental program has been carried out to investigate the lateral behavior of infilled steel frames. Seven specimens included one bare frame and six infilled frames were tested under cyclic loading. The infilled frames were containing single-bay, double-bay frames, rigid frames and pinned frames. Also two infill specimens were tested under combined lateral and vertical loadings. Afterward, an extensive parametric finite element analyses were carried out to achieve more accurate results. The results also show that the stiffness and strength of infilled frames are increased by applying vertical load, but do not affect the properties of equivalent strut. Moreover, it is found that the contribution of infill panel on global behavior of infilled frames is decreased in specimens with pinned connections in comparison with the infill panels in rigid frames. It also concluded that using the struts with the same properties in multi-bay infilled frame are accurately acceptable. In other words, the properties of equivalent struts do not vary with the increase in the bay numbers in the infilled frames.

The construction of resistant structures against blast loads and vibration is essential. Structures are vulnerable to the external loads in different areas. The initial purpose of designing against blast loads include life safety and the prevention of progressive, collapse based on economic considerations. Structures with these qualities are of great importance and should be protected against explosion. 1. Structures with sensitive and expensive equipment. 2. Structures with long-term guidance role. 3. Structures that cause disruption when they are destroyed. The clear understanding of any occurrence and its consequences are required in order to provide an assessment. The literature review of designing steel frame structures against explosion is evaluated in the next part. Bogosian et al. [1] have modeled the blast load (300-1000 kips) on a structure, and in their result, there is a graph that shows the relation between the chance of occurring an event with weight and the distance of explosive materials. Liew [2] have modeled a five floors steel frame against blast and fire loads. The study on the columns of the structure has shown that local inelastic buckling in critical sections will occur in high strain rates. Izadifar and Maheri [3] have evaluated the effects of ductility on the behavior of steel frames against explosion. The graph of force against displacement has been drawn and the parameters of ductility has been studied. An eight-floor steel frame, which has been designed for service load (live and dead load) was evaluated under explosion by Urgessa and Arciszewski [4]. The results of the research show that the joints with side plates exhibit a better behavior than the conventional joints when blasting. They also behave more efficiently than conventional joints because of the use of these joints to move the plastic hinge into the beam. By comparing the behavior of similar joints with differences in the thickness of the bonding sheet, it was shown that doubling the thickness of the bonding sheet reduces the in-plane displacement. Inappropriate design is the main reason for the vulnerability of these structures. The optimal model for performance-based design of steel framework structures resistant to explosion is provided in this study. For the purpose of the study, the authors assessed the three performance levels of IO, LS, and CP. The intended system for structures is the steel bending frame. In the first step, the structures are designed against seismic load for three levels of performance. In the second step, the structures were redesigned against the blast load. In order to investigate the behavior of structures, the following parameters were investigated. Weight of structural materials used Assessment of the designed frames has shown that the weight of structural materials consumed by the specimens against seismic load is less than the weight of structural materials consumed against the blast load. Examine the horizontal displacement of the roofs of the floors According to the results, the horizontal displacement values of the roofs in the frames are lower than the seismic load compared to the explosive load. Check the absolute acceleration of the roofs of the frames The results show that in designing the frames against the seismic and explosive loads, the absolute acceleration of the roofs is reduced from IO to CP level. Also with respect to the amount of explosive and its distance to the frames and the amount of seismic load, it is observed that as the number of floors increases, the absolute acceleration of the roof of the frames is closer to each other under seismic load and explosive load.

This paper examines the simultaneous effect of blast and earthquake loads on the structural nonlinear dynamic responses of the structure. For this purpose, it is assumed that an explosion occurs near the structure during the earthquake, induced by the ground motion. Initially, the pressure caused by the explosion is calculated with two different intensities (i. e., 1000 and 1500 kg TNT at a distance of five meters from the structure) and is applied to the structure at different time intervals. It is assumed that the structure is excited by the Sarpol-eZahab earthquake. In order to investigate the simultaneous effect of earthquake and blast loads on the nonlinear dynamic responses of the structure, four different scenarios are considered. In the first scenario (State A), the explosion occurs at the beginning time of the earthquake, while in the second state (State B), the explosion happens at the time that the strong ground motion will be started. In the third state (State C), the blast load is applied to the structure at the time that the maximum earthquake acceleration occurs. Finally, in the fourth state (State D), the blast load is applied to the structure at the end time of the earthquake. It is assumed that during an earthquake, or at the beginning and the end of the earthquake, the earth's motion causes an explosion near the structure, which has been observed repeatedly in previous earthquakes and causing significant financial and human casualties. Therefore, to study the simultaneous effect of blast and earthquake loads on the structural nonlinear dynamic responses of the structure, a six-story steel structure modeled in OpenSees software is considered. The frame is modeled nonlinearly, and the Steel 02 material is used to model the frame members. Finally, the acceleration, drift, displacement, and base shear curves of the structure are computed. The results show that with increasing the amount of blast load, the structural response has generally increased. In addition, considering the different scenarios, the maximum response of the structure has occurred in state C. Besides, by increasing the amount of blast load, the maximum response of the structure has not been changed by considering the simultaneous effect of the blast and earthquake loads. In the case that the structure is only excited by the blast load, the results also show that the amount of base shear and base moment is much more than the same values for the state that the structure is only excited by the earthquake load. The values of roof rotation, roof drift, shear, and base moment for the states A and D are similar to these values when the structure is only affected by the blast load. This is due to the short time of the blast load and also the low intensity of the earthquake at the beginning time of the earthquake. Therefore, the earthquake load could not change the response of the structure in these cases. At the end of the earthquake, due to the lack of earthquake load, only the structure was excited by the blast load, and the same results occurred. For example, in the case of using 1500 kg of explosives at a distance of five meters from the structure along with the earthquake load, the maximum displacement of the structure is 64. 75% more than the amount of the responses of the structure when it is only excited by the explosive load and also 65. 94% more than the amount of the responses of the structure when it is only excited by the earthquake load. These values were increased by 146. 12% and 3. 44%, respectively, when 1000 kg explosive is considered at a distance of five meters from the structure.

The braced tube structure is one of the most efficient lateral load resistant skeletal systems under seismic loads. This high-rise mega frame has desirable aspects in terms of seismic response. Also, this system increases the resistance potential of high-rise structures in comparison with three-dimensional steel rigid frames. The present study denotes the seismic response properties of four mega braced tube structural systems of 20-story with different bracing configurations, which are the same in plan and loading arrangements, subjected to strong near-field records. The two studied structures have skeletal configuration of centralized braced panels. Moreover, the two other studied models were designed based on mega braced tube system considered as the resistant structure. In order to assess dynamic response parameters of the studied structures, several nonlinear time history analyses were performed. The selected earthquake records contain a variety of wave-like characteristics such as long period pulses and high amplitude spikes in the ground velocity and acceleration time histories. The analytical evaluation of seismic response parameters indicates the desirable performance of mega braced tube structural systems under powerful near-fault records. The aforementioned seismic performances were investigated in terms of maximum lateral displacement, interstory drift as well as absolute acceleration, relative velocity of floors and total base shear along with the integrated formations of skeletal nonlinear hinges. It was obtained that the concentrated configuration of a limited number of aligned braced panels in high-rise framed skeleton is not relatively suitable. Also, dynamic response parameters of the 20-story models with the configuration of centralized braced panels are influenced more while being subjected to near-field ground motions in comparison to the mega braced tube systems. The application of centralized braced panels would lead to the more intensive variation in seismic response parameters. It should be noted that the application of single elements as well as concentric aligned braced panels cannot be effective in controlling the maximum lateral displacement and drift demands. The structural vulnerability assessment indicated that mega braced tube structures have better seismic performance than the other type of resistant skeletons under influencing of large coherent velocity pulses which displayed in the time history of strong earthquake records.

In the aftermath of a large earthquake many buildings can have either disaster-mitigation or disaster-creation roles depending on the extent of their damage and performance conditions. The success of the emergency response in cities depends on the damage extent of the disaster-creative buildings, on the one hand, and the appropriate performance of the disaster-mitigative buildings, on the other. On this basis, with regard to the effective role of buildings in disaster response management after earthquakes, it is important to recognize and evaluate their roles. In order to evaluate the building damage and casualties, the classification of buildings are done based on the type of the building, number of stories and the age of the building. With regard to the previous earthquakes, in addition to these three factors, some other factors should also be considered in the classification of buildings in order to reach more reliable results. This study was conducted with the aim of upgrading the evaluation method of influential buildings by contributing more factors. A case study was done in selected Chizar neighborhood located in the eighth section of district 1 in capital city of Tehran. For structural vulnerability, guidelines No. 364 (Rapid Visual Screening for potential seismic hazard), was used. JICA and Coburn & Spence methods were utilized for risk assessment and evaluating losses and damages. Based on the results of structural vulnerability, 9% of the buildings had low vulnerability, 6% had medium vulnerability and 33% had relatively high vulnerability. The rest of the buildings were out of the scope of the mentioned guidelines. Victims for night and day in the worst scenario (without emergency assistance) are estimated 9. 6% death for night scenario, and 10% death for day scenario. The results showed that in main streets due to the existence of tall buildings and the narrowness of the pathways, there is a threat of route blockage. In case of appropriate emergency disaster response and provisions, 437 people can be saved in day scenario, and 500 in night scenario, respectively.