نشریه مهندسی عمران
سال پنجاه و سوم شماره 12 (اسفند 1400)

Probabilistic seismic demand assessment of steel moment-resisting frames is associated with uncertainty. The most important factors of uncertainty include the inherent uncertainty caused by the record-to-record variability, as well as the epistemic capacity uncertainty due to the model parameters. The first uncertainty can be applied in the form of using an acceptable number of different ground motion records. Capacity uncertainty arises due to the approximate nature of the parameters used to define the structural model behavior which is based on the experimental relationships derived from laboratory results. In the present study, a 20-story steel moment-resisting frame in two cases of uncertain and base model has been investigated with and without considering the capacity uncertainty, respectively. The method of applying such uncertainty has been done by generating random variables in the defined range by Monte Carlo simulation. Based on the results of the incremental dynamic analysis performed for both base and uncertain models, the seismic hazard demand curves for the entire range of demand parameters including limit states of immediate occupancy and collapse prevention has been extracted and compared. Also, in order to evaluate the influence of the fragility and seismic hazard curves parameters on the variation of the mean annual frequency of limit state of the uncertain model, sensitivity analysis based on the above-mentioned quantities has been done. The results indicate the significant effect of capacity uncertainty on increasing the mean annual frequency at the collapse prevention limit state.

One of the causes of early-age cracking in concrete pavements is plastic shrinkage. This shrinkage occurs after the balance of bleeding and evaporation and the formation of negative capillary pressures at the pavement surface. Different environmental conditions cause the rate of evaporation to change, resulting in a change in time of balance and subsequent cracking. This study, using the standard ASTM C 1579 method, examined the relationship between time of balance of bleeding and evaporation, and cracking area in concrete in 27 different environmental conditions, including a combination of three ambient temperatures, three wind speeds, and three relative humidities with using a continuous video recording system and digital image analysis. The results showed that there was a significant relationship between time of balance and severity of plastic shrinkage cracking. By reducing the time of balance from the maximum value to its minimum value, the cracking area increased by more than four times. It was seen that the combination of environmental conditions has a significant effect on increasing or decreasing the severity of cracking, and the fact that only one factor is critical cannot necessarily create critical conditions for plastic shrinkage cracking. Time of balance can be an essential factor in controlling and reducing plastic shrinkage cracking and assessing the effects of different environmental conditions on the severity of cracking in concrete pavements. It is necessary to control this factor during the construction of concrete pavements in different environmental conditions.

Coupled steel plate shear wall (C-SPSW) is a relatively new system that has received less attention from research centers. This system benefits from a high ductility and stiffness, which are the two advantages that make this system superior to the other lateral load-resisting systems. This paper aims to study seismic response of the CSPSWs under near and far-field earthquakes, resting on soil types II and IV considering soil-structure interaction (SSI) effects using the 5, 10 and 15-storey frames in which length of link beams and frame bays is equal to 1.25, 2.5 and 3.75 as well as 2.4, 3.2 and 4.8m, respectively. Based on the analysis results, maximum roof displacement of the 5, 10 and 20-storet frames located on stiff soils (soil type II), does not experience remarkable changes under near and far-field earthquakes but to the contrary, in the case of soil type IV, changes are considerable. Roof acceleration of the structure located on stiff soil, is less than that of the structure on soft soil. In this paper, ratio of base shear to effective weight of the structure was taken into account and it was found that incorporation of SSI effects influences the base shear. Moreover, regarding behavioral modes of the coupling beam and coupling degree of the SPSW, the results indicated that this degree has a meaningful correlation with fundamental period of the structure and the short coupling beams that yield in shear, have a better performance.

Identification of damage to structures in order to prevent its expansion or improvement is an important issue that has received much attention from researchers. Despite presenting different methods for damage detection, the embedded crack identification in beam-columns has received less attention. In this experimental study, a triangular model was used to apply the embedded cracks with using CNC on the laboratory beam-columns. The size of the elements is such that the effective length of the crack is located inside the element and from it has not been removed .To identify embedded cracks, static data indices was used for Euler-Bernoulli beam-columns under axial load. That in this method to calculate static responses a finite element method is used. Then, based on the finite central difference method, the slope and curvature of the horizontal displacements are calculated. For this purpose, in this laboratory study, two simple beams models with single, multiple damage and different loading scenarios were used. In the first step, the laboratory horizontal displacements are recorded and then included in the index. Finally Comparison of laboratory and the numerical results have shown the performance accuracy of the static data base index. Partial difference between laboratory and theoretical result showed noise and errors (making parts, performing tests, sensor errors, etc) that occurred in the laboratory.

Tunneling induced displacements could be dangerous for surface structures and urban infrastructure, if not controlled. Accordingly, different techniques are carried out to mitigate tunneling induced displacements. In this regard, using a diaphragm wall is a practical technique. In this study, the effect of using a diaphragm wall in mitigating the Madrid metro tunneling induced displacements was investigated. Despite mechanized tunneling of the Madrid metro extension, there is a considerable settlements due to a thick layer of made soil ground. In this regard, TBM-EPB tunneling of the Madrid metro tunnel has been modeled step by step and three-dimensional in the finite element code of ABAQUS. The main construction aspects of a TBM are modelled, such as the face pressure, the injection of grout behind the segments, the overcut produced by the gap between the diameters of the cutter-head and the shield. The diaphragm wall is also modeled three dimensional. Varied parameters of the study are the elastic modulus of the wall, the length of the wall, friction between the wall and the soil, the distance of the wall from the tunnel axis and the density of the wall. The results show the elastic modulus of the wall and the distance of the wall from the tunnel axis are the most effective parameters in mitigating of the tunneling induced surface settlements and horizontal displacements. In the distance of 0.7D between the wall and tunnel axis, a wall of 0.5D or C+1D length could be the optimum option to mitigate the settlements.

Having the exact values of boundary conditions is one of the effective way to accurate groundwater models. In the present study, the exact value of constant head boundaries in Birjand aquifer is specified with the usage of particle filter linked to meshless groundwater model. Particle filter known as one of the data assimilation methods applies to dynamic systems in order to improve their performance. Meshless model, one of the numerical models that do not mesh the problem domain, enforces the governed equation to nodes. Birjand aquifer with almost 269 km2 area, has 190 extraction and 10 observation wells. There are also nine inflow and one outflow regions with constant head boundary conditions, which include 105 boundary nodes. After determination of the lower and upper bounds of groundwater head for each node, the exact values of this parameter is computed. Finally, the simulated groundwater head compared with observation data. The closeness of the achieved results to the observation data showed the performance of the engaged method, as the results indicated a significant decrease in RMSE occurs just with the usage of particle filter linked to meshless model. RMSE value reduced to 0.386 m as its previous value was 0.757 m. The results also showed that the model was more accurate when the number of particles in particle filter increased. The RMSE value for 500, 700 and 1000 particles were 0.484, 0.401 and 0.386m respectively.

In the piled raft foundation, in contrast to the pile group, both raft and piles transfer the imposed load to the foundation soil. The concentration of shear stresses and bending moments at the connection point of the pile and raft in the piled raft may cause a structural collapse in the pile while the geotechnical bearing capacity of the pile has not fully mobilized. This problem may be solved by disconnecting the piles from raft and inserting a soil layer between the piles and the raft. This layer in non-connected piled rafts is called cushion. In a non-connected piled raft, the cushion plays an important role to mobilize the bearing capacity of the foundation soil, adjusting the load transfer mechanism, and changing the system stiffness. The behavior of a connected and non-connected piled raft is too complicated to easily estimate the load sharing ratio and stiffness for the preliminary design. In the present research, based on the test results of the pile group and the unpiled raft, an analytical approach is introduced to calculate the load sharing ratio and the stiffness of the connected and non-connected piled rafts. To verify the proposed analytical model accuracy, 21 small scale tests on the unpiled raft, pile group, connected and non-connected piled rafts were conducted. According to the results increasing the number and length of piles, increases the bearing capacity. In a non-connected piled raft, increasing the cushion thickness decreases the load sharing ratio of piles, stiffness, and bearing capacity of the system.

Phosphorus is one of the vital nutrients for plants and algae growth. Low solubility of phosphorus compared of other nutrients, has caused phosphorus plays key role in algae growth and its often limiting nutrient in most freshwater. So that excessive phosphorus level in water can produce more algae that cannot be cosumed by waterbody creatures and can cause eutrophication, water quality reduction and harmful condition for aquatic ecosystem. Therefore, it is important to identify the main sources of entering into rivers, recognizing the mechanism of transport and its distribution as well as the conditions created in rivers due to the advection and diffusion of phosphorus. For this purpose, in this research, after identifying the main sources of phosphorus entry into the river, it investigates and simulates the advection and dispersion of phosphorus in the Qezel-Ozan, Shahrood and Sefidrood Rivers based on field meusring data and using HEC-RAS software. Five scenarios were designed based on changes in environmental and anthropogenic factors and then by numerical simulating using HEC-RAS software, the impacts of phosphorus dispersion have been investigated in the region research area. The result presented that controlling human activities that entering phosphorus to Qezel-Ozan and Shahrood rivers can reduced total phosphorus concentration of Sefidrood river but mass of algae has been increased only by increasing air temperature and discharge of rivers and decreasing by decreased river discharge

Water demand management policies (WDMPs) are being proposed as a solution to water scarcity. Applying any of WDMPs can have far-reaching consequences even on the urban infrastructures like wastewater systems. However, studies on the effects of WDMPs often focused on the water sector, and there is a research gap in the wastewater section. Therefore, in this study, the impact of the application of WDMPs on sewage systems from a social point of view has been evaluated during different scenarios of demand reduction. For this purpose, the Social Life Cycle Assessment (SLCA) method, which is a subset of life cycle thinking, has been used. In this regard, Baharestan city (located in Isfahan province) is selected. The groups (stakeholders) affected by the social effects of WDMPs on wastewater systems have been identified and their characteristics have been determined. Stakeholders are social and local community, workers and consumers. Then, by compiling a questionnaire and using the opinion of experts in this field, the Analytic Hierarchy Process (AHP) method has been used for scoring. Then, taking into account the intensity of the effects of each indicator in each scenario, the social score of all scenarios is obtained. The results show that social and local community has the biggest weight than other stakeholders (wight of 0.45), and safe and healthy living condition is the most important indicator of it. Also, the scenario that has the least decline in water consumption and sewage production is socially better than others.

ABSTRACT During earthquakes, infill walls are imposed by in-plane (IP) and out-of-plane (OOP) seismic loads. After some in-plane seismic vibrations, the worst case for out-of-plane stability of the infill appears when there is the least integrity in the frame-to-wall connections. Using some kind of reliable connectors for frame-to-wall connection is an innovative method to improve their IP and OOP seismic behavior. Regarding that the literature on infilled frames has not focused on this subject yet, the present research was carried out with the purpose of introducing a kind of reliable and efficient frame-to-wall connector and to study its effects on IP and OOP behavior of the infilled frames and the infills. Four half-scale single-story single-bay specimens, including one bare frame, an infill wall and two infilled steel frames having walls of autoclave-cured aerated concrete (AAC) blocks were tested under IP and OOP cyclic displacement controlled loading. The specimens were tested to investigate their failure modes, strength, stiffness degradation, damage evolution in frame and infill, cracking patterns of infill, energy dissipation capacity and out-of-plane displacement of infills. The experimental results revealed that the V type connectors showed good and reliable interaction as far as the safety issues were concerned. Therefore, such type of fasteners can be used as kinds of promising reliable frame-to-wall connectors for AAC infill panels.

The current research seeks to present a novel method for numerical modeling of concrete behavior at meso-scale. In this method, as the stress distribution at the macro scale can be a suitable indicator for critical areas (crack propagate and growth), the areas under stress (critical areas) are identified through numerical modeling at the macro scale (coarse mesh) and using the extended finite element method and topology optimization. Macro-scale critical regions are considered cumulatively using topology optimization. Therefore, critical regions are modeled at the meso-scale, and the rest are modeled on the macro scale. At the meso-scale, the three phases including aggregate, mortar matrix, and ITZ were considered. The aggregate phase was distributed in the mortar matrix using a random algorithm and a Fuller curve. The accuracy of modeling concrete at the meso-scale using topology optimization was investigated by two examples, the results of which show the appropriate accuracy of the method. Furthermore, the method can reduce the computational cost and analysis time compared to modeling the whole sample at the meso-scale. In this research, the piecewise meshing method was used for numerical modeling. Using this method, traction-separation crack growth and expansion are modeled with appropriate accuracy.

One of the common methods in controlling the seismic response of structures is the use of seismic isolators. Isolators reduce the base shear as well as the relative displacement of the floors by increasing the period of the structure. Typically, extreme deformation of the isolator level occurs due to severe environmental factors, which can lead to damage to the isolators; As a result, there is a possibility of permanent deformation in the isolator and also the collision of the structure with adjacent buildings. Therefore, to prevent damage to buildings equipped with base isolations due to severe ground motions, it is important to identify damage at the isolators. In this study, assuming the linear behavior of the main structure, a proposed subspace-based method for identifying the stiffness of the base isolation with a limited number of sensors is presented. For this purpose, using the compression technique, the structure equipped with a separator with a large number of degree of freedom (DOF) is transformed into a two DOF structure; So that the stiffness associated with the first DOF in the reduced system corresponds to the stiffness of the Isolator level in the original structure. Then, using the identified Markov parameters of the system, the reduced structural stiffness is identified. Numerical examples are used to evaluate and compare the performance of the proposed method. The results show that even in the presence of noises in the measured responses, the proposed method detects the amount of damage at the isolator level with acceptable accuracy.

The inconveniences of introducing and modifying the mesh grids in mesh-based numerical methods lead the researchers to meshfree methods. In this research the steady-state numerical solution of incompressible continuity and Navier–Stokes equations, and the standard k-Ɛ turbulence model was investigated in a 2D domain. The computational domain consisting of a 0.5 m×0.5 m square lid-driven cavity was analyzed for five Reynolds numbers of 2.5×105, 5×105, 10×105, 2×106, and 5.5×106. The multiquadric radial basis function (MQ-RBF) was employed with 36 and 121 domain computational nodes to solve the PDEs. The fields parameters were computed using a try–and–error algorithm for solving a set of nonlinear equations, and the optimal values of the shape parameter c and the λ set coefficients were evaluated and discussed for each flow field. According to the results, assuming the independence of the values of the shape parameter c for each flow field at different Reynolds numbers, a predictable pattern can be obtained for the λ set for different Reynolds’ numbers in the studied range. These patterns with the predictor functions of the flow fields were compared to existing benchmark results of the finite volume method (ANSYS Fluent). The Nash-Sutcliffe coefficients of 93-99% and RRSME of about %1 obtained from this comparison indicated the reasonable accuracy of the assumption concerning the independence of the shape parameter c of the Reynolds’ numbers, the repeatable patterns of the normalized λ set, and polynomial predictor functions in the MQRBF method for each flow field.

In past few decades, the expansion of industrial areas and increasing the effluents has led to increase the contamination of heavy metal in soil and groundwater resources. Adsorption is one of the most important processes that affecting in the leakage of contamination. Prevention the leakage of heavy metal contamination and economic considerations are always one of the basic principles in designs. Thus the use of natural and inexpensive adsorbents ,like clay and zeolite, is feasible procedure for the improvement of contaminated soil. In this study, with triaxial tests, the behavior of mixed sandy clay (base composition) with 10% of different low plasticity (kaolinite and zeolite) and high plasticity (bentonite) adsorbents is studied in both contaminated and uncontaminated states. The results show, as the concentration of lead heavy metal increase in soils with low plasticity adsorbent, the shear strength and internal friction angle decrease by about 20% and 14% respectively. As the type of adsorbent mineral changed, the resistance parameters of contaminated soil show different trend. Increasing the concentration of lead in the soil with bentonite adsorbent, has led to form the flocculation structure and it cause shear strength and internal friction angle increase a bout 18% than uncontaminated state. Also, cohesion in compositions with low and high adsorbent increases and decreases by about 30% and 19%, respectively.

Considering the increasing hostile and terroristic threats in the country, it is important to consider the passive defecncecriteria in structures. The desirable properties of steel and concrete cab be used simultaneously to increase the strength of structural members. Concrete-filled steel tube columns (CFSTs) have been proposed as an efficient system in the previous years. The main problem with using this type of column is how to connect the beam to such a column and extensive researches has been done for seismic load scenarios. Despite the excellent resistance of these types of columns to the blast load, no comprehensive investigation has yet been conducted on the performance of beam-to-column joints under blast load. In this paper, the behavior of three types of beam-to-column connections under 5 blast scenarios is investigated. ABAQUS software was used to conduct the research. Verification was first performed using the results of an experimental study and a good agreement was observed. The behavior of beam-to-column blast-loaded connections was investigated using 16 different models using explicit nonlinear dynamic analysis. The results were compared in terms of stress, strain and damage contour as well as force, energy absorption, displacement, rotation and torsion diagrams. It was observed that when the connection was carried out as an extension of the beam inside the column, all parts of the column contributed in the load carrying and energy absorption and very good behavior was observed. In this case, the plastic joint in the beam is formed away from the column face.

Over the recent decades, with spreading the unusual events such as fire, blast, and vehicles collision, studying the behavior of structures subjected to abnormal loadings has been attracted the attention of researchers and structural engineers. Among the various scenarios of impact loads, the collision of light and heavy vehicles to the external column of steel buildings accidentally and or intentionally is important as a research and an applied topic. The impact loads caused by vehicle collisions to column of buildings are usually not considered in the design, so it's necessary that the effect of these loads should be studied on the nonlinear performance of structures. In this study, the steel moment-resisting frame structures 2, 5, 8 and 12-story with intermediate ductility are designed for gravity and seismic loads and then nonlinear dynamic analyses are conducted under the impact induced by Light and heavy vehicles collision to corner column of side axis by OpenSees software and fragility curves are proposed based on the different damage levels. Finally, structural responses of studied frames are investigated and compared due to the collision impact with different velocities until the occurrence of dynamic instability. The results showed that the impact induced by light vehicle collision at velocities 80, 100, 140 and 130 Km/h and impact induced by heavy vehicle at velocities 50, 60, 80 and 70 Km/h has been caused dynamic instability in the desired frames 2, 5, 8 and 12-story, respectively.

Shear module is of the most crucial soil dynamic properties in seismic geotechnical engineering. The replacement of a part of cement, the production of which is one of the most important sources of CO2 emission in the world, with natural materials such as zeolite is of great importance. In the present study, the cyclic behaviour of pure sand is compared with the cyclic behaviour of sand grouted with cement and zeolite. The sand used in this research was taken from Babolsar, which is classified as a poorly graded sand based on the Unified soil classification system. The effects of the confining pressure, the shear strain and the replacement of cement by zeolite on the shear modulus are studied. All the specimens were prepared by the wet tamping method and cyclic triaxial tests were performed with three different confining pressures of 100, 200, and 300 kPa in the moderate shear strain range. The results show that Shear modulus values of the cemented sand specimens with a water-to-cement ratio of 1 are greater than that of the pure sand specimens in all range of shear strains. The shear modulus values increased with the replacement of cement by zeolite of cemented samples. Therefore, the replacing of cement with zeolite can be considered from an environmental point of view. By increasing the confining pressure, the shear modulus values of the pure sand, cemented sand, zeolite cemented sand specimens increased. This increase is significant for cemented and cemented zeolite specimens at larger confining pressure range.

Highway Bridges are a major part of the transportation network and an important part of a country's national economy. Despite numerous studies on their seismicity and fragility, very little research has comprehensively addressed all of their dimensions. In this regard, the purpose of this study is to consider the unique details of the design period of these bridges in Isfahan City. To do so, the bridges of the last 50 years in Isfahan were examined through fragility curves. Considering uncertainties and changes in loading in this study is one of the most important surveys conducted through the non-linear history-time analysis method. The 1971 San Fernando and 1989 Loma Prieta earthquakes revolutionized the philosophy of bridge design. Therefore, the study of the three bridges that were designed and built in the three periods before the San Fernando earthquake, after that and after the Loma Prieta earthquake has been done. The results of this study showed that due to the significant improvements in different seismic codes, the possibility of damage to bridges at different times, under the influence of different earthquake intensities is likely. Also, according to the results of this study, column failure is not the sole criterion of bridge failure and the involvement of different components of a bridge in probabilistic seismic evaluation of that bridge will lead to greater fragility. Therefore, in order to evaluate the probabilistic seismicity properly, in addition to the column, the involvement of all bridge members must be considered.

Nowadays, industrial environmental management with the aim of preserving the environment has become one of the crucial matters to industries. Rising global concerns about the negative effects of industrial activity have led to a variety of changes in governments' policies and strategies to improve environmental performance. Hence, it is very important to study the environmental performance of industries This study evaluates and ranks the Iranian provinces o in terms of environmental performance of industries, various dimensions. This research defines a multidimensional set of environmentally friendly manufacturing criteria by examining the various aspects of industrial activities impacts on the environment and also with the assistance of experts’ guidance for evaluating the industries at the provincial level. Then, we use a combined approach based on decision-making trial and evaluation laboratory technique and analytic network process (DANP) method to calculate the interactions between the research criteria and sub-criteria along with their influential weights. In the end, we utilize the additive ratio assessment (ARAS) technique to obtain relative utility coefficients (closeness coefficients) and ranking the provinces. Generally, this study concludes that industries in northwestern and southwestern provinces of Iran are more environmentally friendly than other provinces. In this evaluation, Bushehr, North Khorasan and Khuzestan provinces were ranked first to third with their relative utility coefficients of 0.488, 0.412 and 0.401, respectively.

Biological drying is one of the pre-processing methods of waste to reduce its moisture. High humidity of municipal waste makes it difficult to manage this type of waste, reduce the thermal value, produce leachate and complicate disposal and recycling methods. Therefore, this method can be used as a method of preprocessing organic waste to produce heat and convert it into a fuel with high calorific value. The aim of this study was to investigate the effect of aeration on reducing the moisture content of food waste by biological drying of perishable organic waste. Hence, a new pilot-scale biological drying system was designed for municipal solid waste processing. Also, important and influential factors on biological drying including mixing rate, moisture, particle size, aeration time, aeration amount and bulking factor were investigated. Finally, the pilot performance on perishable food waste prepared was evaluated with two aeration rates. The results showed that the weight, volume and moisture content of the waste was significantly reduced and the ph value of the waste leachate was stabilized at 8.35. Moisture is also greatly reduced so that at the end of the first phase is equal to 25.10 and the second phase is equal to 21.80 and volatile solids are increased. The final weight of the waste reached 6.86 kg and as a result aeration in reducing the moisture content of perishable food waste by biological drying method is a sustainable method to reduce the moisture content of the waste

Optimization in TBM cutterhead design is essential for increasing its performance. Lace design for the cutters, buckets, and manholes, is one of the major considerations in the design of the cutterheads. An optimum lace design is necessary to avoid cutterhead deviation, vibration, stress concentration, etc. during its operation. TBM manufacturers usually utilize two common lace designs of radial and spiral configurations. Each of these designs have its own disadvantages which may cause difficulties in achieving an efficient design of the cutterhead. This paper presents the basis of the lace design of the hard rock TBMs. With the consideration of the problems of the radial and spiral configurations, a new method of “evenly distributed lace design” is introduced and the steps of achieving the final layout of the cutterhead is explained with its required parameters. The parameters are obtained from statistical analyses conducted on the gathered design information of many TBM cutterheads from around the world. The results, show that the new method is very efficient in both evenly distributing the cutters on the cutterhead surface as well as in minimizing the unbalanced forces and moments.

The effect of freeze-thaw cycles on the hydraulic conductivity (HC) of clayey barriers in water retaining structures and municipal solid waste landfills is a key issue in designing barrier systems in those structures. The effect of freeze-thaw cycles on the hydraulic conductivity of a compacted clayey soil from Nazlou Region of Urmia City and a geosynthetic clay liner (GCL) was investigated. The effect of effective stress on the hydraulic conductivity change of clayey soil in freeze-thaw cycles was studied for water and leachate. The flexible-wall triaxial hydraulic conductivity apparatus was used to measure the HC of specimens subjected to freeze-thaw. During the freezing process, ice lenses grow in soil sample and when they melt, a network of cracks is left causing the increase of HC. Increasing the effective stress reduces the increased hydraulic conductivity due to freeze-thaw. The results show that on the contrary to compacted clayey soil, the application of freeze-thaw cycles does not significantly affect the HC of GCL. Interaction of clayey soil with leachate leads to decrease in thickness of diffuse double layer and thus the hydraulic conductivity of clayey soil increases. Increase in hydraulic conductivity of clayey soil and GCL subjected to freeze-thaw and permeated with leachate is lower than that for water.

Selecting a construction project manager is one of the most important processes in human resource management in the construction industry. Deciding on the issue of hiring a project manager will be a complex and multivariate issue. The purpose of this study is to provide a hybrid model that optimally solves the issue of ranking and selection of a construction project manager by using decision-making techniques. The proposed model is based on fuzzy linguistic decision criteria, to solve the construction manager selection based on criteria derived from the Delphi method based on previous studies. In this research, two methods of group decision making in ranking and selecting the construction project manager are presented. The Delphi method extracts the criteria, while the fuzzy TOPSIS method selects the optimal candidate. The results show that the use of multi-criteria decision-making methods in the construction project manager selection, increases the efficiency of the process and because it considers various criteria, in the end, efficient managers in accordance with the needs of the project-based organization is a candidate in the recruitment process. One of the features of the proposed approach is to minimize the involvement of subjective judgments in the selection of the construction project manager. This approach can also help decision makers of project-based organizations in identifying and determining the basic criteria before selecting a construction project manager and facilitate the decision to select the best construction project manager based on multiple criteria and options.

One of the effective methods to reduce the impact of earthquakes on structures and improve the seismic performance of structures is the use of seismic isolation system. In this paper, the seismic performance of asymmetric isolated structures with different bracing systems under near-fault strong ground motions is investigated. Nonlinear dynamic analysis are performed under the simultaneous application of horizontal and vertical components of seismic acceleration. For this purpose, three types of chevron, cross and zipper bracing systems in 5 and 10-story structures with 0%, 10% and 20% mass eccentricity have been studied. Nonlinear time history analysis is performed by seven selected accelerogram. First, the symmetrical structure was analyzed in fixed and isolated base states. Then, the asymmetric effect on two eccentricity cases 10% and 20% in the target structures was compared. The average of shear force, drift and rotation of floors and input energy to the structure are the parameters studied in this paper. With an increasing eccentricity of the structure, the energy absorption by the isolator is reduced and the base shear is increased. Among the different bracing systems, the energy absorbed by the isolation system in the structure with zipper bracing increased by 53% and the base shear rate decreased by 80%.Based on the analysis results, base-isolation in the structure with cross-bracing in symmetrical, and asymmetric has caused a reduction of more than 70% of the floor rotation compared to other bracing systems.