نشریه مهندسی عمران
سال پنجاه و سوم شماره 1 (فروردین 1400)

Plastic shrinkage cracking in concrete pavement is a place for ingression of water and corrosive substances to the pavement, which reduces its durability and ultimately leads to failure of the pavement slab. The use of fibers is one way to control these cracks. This study investigates the effect of the addition of macro polymer fibers in comparison with micro polymer fibers on plastic shrinkage cracking in concrete pavements. For this purpose, one type of micro polypropylene fibers and two types of macro polypropylene fibers in a volume of 0.1% were used to make the samples. Mechanical tests including compressive, tensile and flexural strengths and evaluation of plastic shrinkage cracking according to ASTM C 1579 in climate conditions including relative humidity of 20%, wind speed of 30 km/h and at temperatures of 35 and 40 Celsius degrees, were performed. The results showed that concrete samples containing both macro and micro fibers had better performance in controlling cracks than control samples. Meanwhile, micro fibers performed better in controlling crack width at both temperatures conditions. In contrast, macro fibers showed a better effect in reducing the length of cracking, especially at higher temperatures. The use of macro fibers can significantly reduce the length and area of plastic shrinkage cracking in concrete pavements.

By the concept of control structures a new shell configuration for a steel energy dissipative device designed for earthquake protection of structures is proposed in this study. This device is named a nested-eccentric-shells damper (NESD). This device is made of a large cylindrical shell that surrounded three small cylindrical shells. The conventional methods of welding or metal casting can be applied in constructing this damper. The configuration of the shell-type components is designed in such a way that to be able as a combination of series and parallel springs. To assess the performance of this damper, numerical analysis and full-scale testing are run. Hysteretic loops obtained from the analysis with highly ductile performance are applied to determine the behavior of this proposed damper. The results indicate that the nested-eccentric-shells damper is of a stable behavior in hysteretic loops, and can provide appropriate damped energy subject to cyclic loading. However, in order to improve the performance and interaction of the internal members of this damper, a thickness ratio is proposed for the inner shells and the usefulness of using this modification in numerical analysis has been proven in this study.

In this study, the bond strength and failure mode of CFRP strengthened concrete in tensile and shear stresses are investigated using nonlinear finite element and experimental method. Due to the fact that in the study of mechanical behavior of concrete strengthened with CFRP sheet, the assumption of homogeneity of concrete leads to unrealistic results, so in this study, a meso-scale model is used to model concrete. The mesoscopic model of concrete includes three-phase inhomogeneous material consisting of aggregate, mortar and Interfacial Transition Zone (ITZ). Tests performed include "pull-off" and "twist-off" to determine tensile and shear bond strength. The results show that the tensile and shear strength of the finite element model is 18% and 13% higher than the results of the "pull-off" and "twist-off" tests, respectively, which are due to laboratory influencing factors and ignoring They are acceptable in numerical modeling of this difference. Also, the tensile strength of the numerical and experimental models is 34% and 33% lower than the shear strength, respectively. According to the obtained results, the debonding in the CFRP strengthened concrete sample was from the substrate concrete. The results show that the micro-cracks, followed by debonding in the mortar and ITZ phases of concrete, due to high porosity and lower strength than the aggregate phase, spread easily.

Introducing the behavior of reinforced concrete materials is generally considered as one of the complex parts of modeling in finite element software. On the other hand, entering accurate material information has an effective role in software output results. There are several methods in ABAQUS software for nonlinear analysis of reinforced concrete, one of which is the use of a damaged plastic model of concrete.In this method, entering the mechanical properties of concrete is of special importance, so that in case of insufficient data entry, many errors are created in the results and sometimes cause no convergence despite spending a lot of time analyzing in the software. In most numerical modeling in ABAQUS, it is noted that by eliminating the number of points in the inelastic stress-strain curves and in the tensile damage parameter, despite the reduction in analysis time, what errors occur for software outputs.In this study, according to the conditions of ABAQUS software in entering numerical values that should be positive for plastic strains and with increasing strain, the amount of plastic strain should also be ascending. It becomes plastic. Therefore, first, structural analysis is performed by entering the stress and compressive strain points of concrete, compressive damage parameter (dc) and tensile damage parameter (dt) completely, and then by changing the number of stress points and tensile strain and tensile damage parameter (dt), this analysis is repeated. Finally, the results of the displacement load curves at the output are examined and compared.

Fluid storage tanks are one of the most important components of vital arteries that play a key role in various water and industry networks, including oil, petrochemical, and water transmission systems. A study of seismic damage reports of tanks in previous earthquakes shows that one of the major damages in reinforcement concrete tanks that are commonly used to store water is cracking and liquid leakage. Therefore, in the present paper, the analysis and evaluation of ground concrete tanks are investigated to develop the fragility curve for these tanks. For this purpose, nonlinear numerical analyzes have been performed for three types of concrete cylindrical tanks with variable height to diameter ratio, taking into account the cracking of concrete. Then, the fragility curves of the tanks for the critical crack width are extracted according to the recommendation of Journal 123. These curves are compared with the results of previous research conducted in a linear manner without considering the cracks in the reservoir body, and the effects of applying crack widths in the analyses are discussed. The results indicate the need to apply tank cracking conditions in increasing dynamic analysis and extraction of fragility curves.

Red-light running is one of the prevalent sights at signalized intersections that vehicles pass without caring for the light. A red- light runner not only ventures his life, but also the safety of other road users. Elaborating features of at-fault drivers and vehicles that issue the risk of crashes could result in recognizing important factors and lead decision-makers to find out actions they could prevent them. This study aims to identify the driver and vehicle characteristics affecting red-light running crash occurrence risk at signalized intersections of Iran. The methodology of the study was based on quasi-induced exposure concept and logistic regression model for 10 independent variables and one binary target variable of "driver status". The statistical population included 12445 red-light running crashes from 2012 to 2016. The results demonstrated that vehicle type, residence, license type, and education level affect drivers' fault status in these crashes. based on the logistic regression model, truck and emergency vehicles, foreign drivers, and type 2 driving license increase the risk of drivers' being at-fault. However, academic education level of drivers decreases at-fault risk. Finally, some countermeasures were suggested for decreasing the risk of red-light running crashes.

This paper presents the results of an experimental study on the properties of environmentally friendly concrete. In the making of specimens, 0%, 15%, and 30% of ordinary Portland cement (OPC) was replaced by recycled concrete powder (RCP) and silica fume (SF). In addition, 0%, 50%, and 100% of natural aggregates (NA) was replaced by recycled concrete aggregates (RCA). In the production of RCA, 3 types of concrete waste with initial strength of 20, 40, and 80 MPa were used. In this study, rheological, mechanical (compressive, splitting tensile and flexural strengths), economic and environmental (GWP) properties of 28 mix designs were investigated. The results showed that the use of RCA and RCP has a negative effect on rheological and mechanical properties. However, the results showed that the use of RCA and RCP has a positive effect on environmental and economic properties. Moreover, the results indicated that the negative effect of RCA can be prevented by increasing the initial strength of RCA, and the negative effect of RCP can be prevented by using SF. Finally, by optimization of mixing designs, it was concluded that it is justified to use 50% of RCA with initial strength of 40 and 80 MPa and 30% of RCP and SF, in terms of rheological, mechanical, economic and environmental properties.

Rework is one of the common problems in the construction industry. Despite the many studies that have taken place in the world, the lack of a comprehensive examination of the rework causes in Iran is evident. In addition, there is a need to provide an efficient and effective way to improve the rework issues. Therefore, in this study, using the survey method through the questionnaire, the main factors of rework in Iran were identified and ranked according to the criteria of cost, time, quality, safety and satisfaction of the project team by Fuzzy-TOPSIS method. Then, lean construction techniques were considered as a strategy to prevent rework, and the impact of these techniques on the importance of the rework factors was tested. The results of 52 questionnaires showed that the factors related to the client, the construction phase and the design phase were three main factors of the rework in Iran. Factors for insufficient turnover and commissioning resourcing, late client changes, delaying financing and contract delivery, insufficient skill levels, and ineffective management of project team are also the most important sub-factors, respectively. On the other hand, the lean construction measuring of the projects was examined through the Lean Project Rating System (LPRS) with 14 factors. The results showed that some of the lean construction factors considered in this study (including focus on communication and collaboration status, the use of IT and RFI, and the use of BIM) significantly alter rework and the importance of the its causes.

Damage of canal concrete lining is one of the common problems in irrigation and drainage network projects. Results of several Studies show that swelling of unsaturated expansive soils usually led to theses damages. In recent paper, this phenomenon is studied by physical modeling. In this paper two different ways are studied to control and reduce the effect of swelling soil on canal lining. The first way is the optimization of number and location of joints on canal linig and the second is the investigation of the effect of canal wall slope on soil-lining interaction behavior. For this purpose the irrigation and drainage network of Tabriz plain canal that is under construction on expansive soil is selected as a refrence for geometric properties of canal section. The physical models are constructed as small scale (1/10) in laboratory and two techniques is used in tests: PIV method and instrumentation. By using of PIV method displacement vetors, volumetric countours and magnitude of them in bed soil are obtained and drawn. In addition the results of physical modelings show the effect of joints to control and distribute of expansive soil-canal lining interaction forces. In the other hand the strain gauges recorded data show that the relative displacement of panels and destructive bending moments of lining are decreased by considering joints on location of maximum internal forces in the canal section. Also it is inferred that the variation of canal wall slope is not an effective way to reduce the lining damages.

With attention to the importance of the three span continuous bridges and complexity of analyzing structures with multi degree of freedom, utilizing desirable numerical models to estimate the internal forces of this group of structures is highly effective. A new analyzing method is introduced in this study which can be used to the 3-span continuous bridges with constant section and heavy moment resistance in transverse direction. The defined pattern is based on employing sinusoidal shape function both the bridge’s deflection shape and its corresponding applied forces. This model is developed by assuming a simple beam on the elastic constraints and thereby its results can be earned by minimizing the created potential function of whole structure. Creating a desirable manual method in calculating the internal shear forces of columns in the three-span bridges is a good comparative idea over the complicated method proposed by Aashto needing 3-dimentinal modeling in related software. By considering 5 different state of an example sample and analyzing those, the obtained results of the suggested way proves its high precision and efficiency on controlling the calculations manually because of having the deference lesser than 10 percent related to the exact method.

A stepped spillway is a hydraulic and cost effective measure to dissipate the energy of large water flow over the spillway. Due to some limitations in stepped spillways, this study is intended a plan to increase and improve the effectiveness of energy depreciation. For this purpose, the effect of the wedge-shape elements on the velocity and pressure changes over the steps, water level and energy dissipation at downstream the stepped spillway are evaluated. In this regard, several forms of wedge elements are studied with changes in wedge arrangement and the rate of discharge by using numerical model of Flow-3D, and the appropriate models from the aspect of the most energy depreciation are selected and studied in the laboratory. In the laboratory, 25 experiments were performed on 5 physical models.Numerical and experimental results show that the addition of wedge elements on the stepped spillway has reduced the velocity and water depth at downstream of spillway to about 80% and 30%, respectively, and the energy dissipation over the stepped spillway increased by about 2.7 times. Also, by drawing the distribution profiles of pressure on the edge and the floor of steps, it was observed that the negative pressure in the horizontal section turned into a positive pressure. Also negative pressure in the vertical section decreased up to 96% and positive pressure increased about 2 times. As well as, by increasing the density of the elements, the results that increase the energy dissipation are more remarkable.

Traffic congestion has been rapidly increasing in cities. It leads to an increase in transit travel time and loss in reliability of transit vehicles. The implementation of the priority system for transit at signalized intersections with high traffic volumes will help reduce transit delays and red lights stops at these intersections. In this paper, we propose an unconditional active signal priority control method for public transportation system, which includes regular buses and a Bus Rapid Transit. we examined 11 different modes of bus availability at the intersection, based on the estimated time of transit arrival. Reduce transit delays at the intersection, increase the convenience and reliability of public transportation, increase the total intersection efficiency and reduce the negative impact on personal vehicles are also considered. Finally, a model simulation was conducted by VISSIM by writing an algorithm modeling in a signalized intersection with BRT and regular bus in Isfahan City,Iran. the results showed that, due to the implementation of this method, BRT passengers delay decreased by an average of 65% and decrease regular bus passengesrs delay by an average of 7% comparing to existing signal control scenarios.

In the present study, the removal of heavy metals (in the case of cobalt removal) from contaminated water using Fe3O4 magnetic nanoparticles and the effects of pH factors, time, cobalt concentration and temperature on cobalt removal were investigated and to describe the data obtained Langmuir and Freundlich equilibrium isotherms have been used for absorption experiments. The experiments were designed with the Taguchi method in the Coalition software, which uses a partial factorial method. Nanoparticles are synthesized by co-operation in the laboratory, and then experiments are performed on four levels of each factor on a simulated solution containing cobalt, and the results are analyzed with the aid of the Coalytic software using the Taguchi standard analysis method. The highest cobalt adsorption rate is 81%, pH is equal to 9, 15 minutes, initial concentration of cobalt is 7 mg / l, and 60 ° C. Also, according to the analysis, the optimum conditions in pH state are 9, the remaining 10 minutes, the initial concentration of cobalt is 25 mg / L, and 20 ° C. The rate of yield in cobalt adsorption is expected to be 383/86 percent. At the end, the result of the experiment under optimal conditions on real industrial waste water contains 36 mg / l of cobalt 60 with an absorption rate of 6.7%, which is 17.1%, due to changes in experimental and actual conditions. The data obtained from adsorption isotherms are consistent with the two models and are more fitted to the Freundlich model.

Extensive damages in welded unreinforced flange (WUF) connections in 1994 Northridge earthquakes has led to the idea of using reduced beam section (RBS) connections and Drilled Flange (DF) connection to prevent brittle failure modes in welded joints. In this paper, the seismic behavior of DF moment resisting connection with slot holes as an easy-to-construct method for DF connection in seismic regions was investigated. DF connection is made by drilling at top and bottom beam flange along beam main axis to establish intentional weak point to reduce stress concentration at beam to column flange welded connection. In this investigation, Finite Element models which were validated with previous experiments were utilized to consider the effect of slot holes compared to circular holes on rupture potential of beam to column welded connection. The utilized FE models of DF connection with various geometric properties and different panel zone strength ratios were developed to investigate the optimum slot hole configuration and reduce the rupture potential at CJP groove weld. The results showed that the optimum drilled slot holes is able to shift the plastic strain at beam to column welded connection having the ratio of slot hole length to hole diameter (L/D) by up to 2. Using the latter holes configuration, the plastic strain at beam to column weld connection and around the holes decreases up to 28 and 70% respectively compared to corresponding values of DF connection with circular holes.

To design safe transportation systems, it is unavoidable to completely recognize the complicated behaviors of bridges under earthquake. The past earthquakes showed that horizontally curved bridges are highly affected by earthquakes, especially near-fault earthquakes, due to irregular geometry. The previous studies indicated that magnitude; PGV and TP have been the three most effective near-fault-earthquake parameters. In the present study, the attempts were made to determine the effect of these parameters on such bridges using a verified software model by a field test and analyzing two horizontally curved bridges. Three suites of near-fault records were used in order to conduct time-history analysis with three parameters, namely magnitude, PGV and TP. In each suite, two of these parameters are almost constant and third parameter is variable in order to observe its effect on result. The results indicated that the change in PGV has the most significant effect on the behaviors of such bridges. Also, the effect of TP increases in longer bridges. If the difference between lateral displacement of two ends of deck is considered as criteria for assessing potential of Deck rotation, increasing in bridge length and being in near-fault area can lead to increase in bridge deck rotation behavior, respectively up to 2.37 and 2.47 times.

The separation of ions from wastewater and environments such as hydrometallurgy has been a major challenge in the development of ion flotation in recent years. A few studies have been carried out on the kinetics of metal ion removal by ion flotation. In this study, a new model using gene expression programming (GEP) method is proposed to predict the kinetic constant of zinc ion removal (k-Zn(II)) from synthetic wastewater with sodium dodecyl sulphate as collector. The efficiency of ion flotation is depends on both the amount of ion removal and water removed during the process. In this regard, the water removal kinetics constant (k-W) was also investigated. The effect of important parameters on k-Zn(II) and k-W including the ratio of SDS/Zn(II), the activity coefficient and the pH were investigated. The values of R2, RMSE and VAF of the GEP models for the testing data for k-Zn(II) were 0.98, 0.66, and 98.9 and for water removal they were 0.94, 0.004 and 0.93, respectively. The results indicate the higher performance of GEP models for the prediction of k-Zn(II) and k-W. The sensitivity analysis of GEP models showed that k-Zn(II) and k-W are more sensitive to pH and the ratio of SDS/Zn(II), respectively.

Nowadays, there are various types of existing buildings with poor seismic detailing so they cannot cover the seismic code provisions. Accordingly, the seismic rehabilitation technics should be implemented for these structures. Eccentrically Braced Frame having vertical link is a new strategy for retrofitting of existing RC buildings. In this article, three types of reinforced concrete structures with the same architectural plan having 3, 5, and 8 stories are retrofitted with Eccentrically Braced Frames having vertical links and the seismic fragility curves are developed based on Incremental Dynamic Analysis (IDA) in OpenSEES. The demand statistics in terms of maximum inter-story drift ratio are obtained for 20 sets of ground motion records, the capacity is determined according to the HAZUS-MH limit states, and finally the corresponding seismic fragility curves are developed. The results represent the effect of the implemented retrofit strategy on the seismic vulnerability of this subclass of structures. The median seismic fragility for 3, 5, and 8 story models are increased 35%, 90% and 146 % accordingly, at the complete damage state.

Today, science of risk analysis and seismic improvement of structures are from the earthquake engineering branches, whose process is very long, bulky and costly.One of the most important problems in this field is the timeliness and the high error rate, so achieving a logical result can be used by decision makers to solve problems.The goal is to provide a method to help accelerate earthquake risk analysis through refurbishment studies using neuro-fuzzy tools.400 schools were selected from Shahrekord and suburbs schools and then evaluated their seismic risk acceptance using a quick evaluation checklist based on the Rapid Assessment Guidelines of Buildings 364 and the ATC methodology.Also, with the help of wika software, among several structural data, the most effective ones were selected based on the number of replications and the value of the selection, then Anfis software was used to design the neuro-fuzzy system.In order to check the accuracy of the designed model, we first compared the level of risk obtained from the neuro-fuzzy system and the actual level of risk, and in the next step, we calculated the amount of dispersion of the outputs of the system and compared with the results in the data. This implies adapting the results of the neuro-fuzziness system and the results of the qualitative assessment and proper operation of the system.One of the main advantages of this method is the modeling of uncertainties, the entry of information from the structure by qualitative and quantitative methods, and the high speed of the risk analysis process.

management of these resources. The use of modern methods, including ANN and evolutionary algorithms in estimating water quality, due to its high speed, convergence and efficiency, saves and reduces costs and the best management. The main purpose of this study is to evaluate the results of the chemical analysis of groundwater samples from 14 wells in Jolfa plain and also estimate the ground water quality parameters using imperialist competitive algorithm (ICA) and ANN. Therefore, ground water quality parameters include TDS, EC and SAR estimate using imperialist competitive algorithm (ICA) and ANN and groundwater resources quality in terms of drinking, agriculture and industry were examined by Wilcox, Schuler and Piper and standards. Correlation coefficient of (R2) 90%, indicates the acceptable accuracy of ANN compared with ICA algorithm in estimating groundwater quality parameters. By using different diagrams the results show that the hardness of samples are too much and not suitable for drinking. It should also be noted that a very high hardness and corrosion of sample, water not be used in industry. The salinity of 7 samples is very high and according classification is located in C4S2 class and not suitable for agricultural consumption.

Today, in most of megalopolises such as Tehran, the lack of restriction on gasoline motorcycle traffic in contrast to restrictions on car usage such as odd-even scheme causes increasing in gasoline motorcycle usage. Therefore, to decrease air pollution and noise pollution produced by gasoline motorcycles, electric motorcycle usage has been encouraged. This study was carried out based on 503 interviews with gasoline motorcyclists who are working in the central part of Tehran and identified factors affecting their willingness to purchase electric motorcycles in case of gasoline motorcycle ban. Accordingly, the role of variables such as motorcycle characteristics, socio-economic characteristics and motorcyclists' attitudes toward gasoline motorcycle usage were investigated through a binary logit model. Results show that motorcyclists who have purchased their gasoline motorcycle because of its cheap price, those who drive more and those who have older motorcycles are less willing to purchase electric motorcycles. The paper provides a discussion regarding the model application.

In first part of this paper, the theory of design of X-braces using different steel grades introduced and its effects on different frames verified using nonlinear static analyses. It was found hat using lower grade steel in X-braces increases the stiffness, energy absorption capacity, dampingand ductility of system and decreases its lateral drift. In order to completely investigate behavior of steel structures with X-bracing system in design with different steel grades and consider their dynamic behavior, the frames with different stories studied using advanced nonlinear static and Incremental Dynamic Analyses (IDA). The results presented as comparative diagrams and tables. The near and far field earthquakes used for dynamic analyse sand their seismic performance studied. Therefore, this research can lead to better investigation of seismic behavior of X-braced systems in design with different steel grades. The proposed theory along with analyses show that building codes and steel seismic design specifications can consider the effects of steel grades in seismic parameters definition of structures.The comparative diagrams and tables show that the seismic behavior of X-braces designed with lower grade steel improves considerably. In addition, the response of structures under near field earthquakes is bigger than related parameters under far field earthquakes.

Crude oil is one of the soil and water pollution sources which changes the geotechnical properties of the soil via both physical and chemical processes. Carbonate sand which found in oil-rich and continental regions is exposed to oil pollution so that studying the effect of oil and petroleum products contamination is unavoidable. On the other hand, injecting colloidal silica solution, stabilization and improvement of oil-contaminated sand has been investigated broadly. In this research, several triaxial undrained-unconsolidated tests were conducted to investigate the shear strength of carbonate sand contaminated with crude oil as well as contaminated sand stabilized by colloidal silica injection. The results showed that oil pollution reduced the maximum shear strength and the friction angle of carbonate sand, as well as a significant decrease in elasticity modulus while oil content increased. In injected specimens, colloidal silica increases the shear strength, cohesion and stiffness significantly relative to the oil-contaminated ones.

this research, an inverse solution has been employed to simulate the movement of TCE. To evaluate inverse solution, HYDRUS-1D (asa numerical solution) and STANMOD (as an analytical solution) software were used with two transport models including: convection-dispersion equation (CDE) and Mobile-Immobile model (MIM)). In this study, a set of data from Yolcubal and Akyol (2001) were used at three TCE concentrations of 110, 113 and 1300 mg/L. The research was conducted on the loamy-sand and carbonate soil with a mean bulk density of 1.2 g/cm3. Experiments were carried out in columns with a length of 15 cm in stainless steel in saturated conditions. TCE injection continued until the effluent concentration was equal to the injection concentration (C/C0=1). At different time step, the water samples of the column output were taken to determine the TCE concentration and the breakthrough curves (BTC). The results of HYDRUS-1d and STANMOD software showed that the MIM model had a higher correlation coefficient than the CDE model with respect to the match BTC. The highest correlation coefficient was 0.97 at the concentration of 1300 mg/L with inverse-analytical solution and MIM model. The minimum error was zero for estimation of the dispersion coefficient (D) at CDE where it is 3.5% at MIM. The error rate was minimum at the concentration 113 mg/L for adsorption isotherm (Kd) coefficients in the inverse numerical solution and the same result for retardation factor (R) in an inverse-analytical solution. It means that the rate was higher at the other two TCE concentrations.

Interaction study on shaking tables is considered necessary for such devices to guarantee their operational accuracy in vibration simulation. In such studies, accurate estimation on dynamic characteristics of foundation of shaking tables and their neighboring soil is usually required. In this regard, experimental studies on the soil or on the foundation after its completion is recommended to reduce uncertainties in operation of the table in near future. In this work a forced vibration study on the foundation of a six degrees of freedom shaking table (to be operated by International institute of earthquake engineering and seismology) have been performed. In addition to the measured excitation information collected for determination of dynamic characteristics of the foundation, that part of the vibration that transfers to the soil (in different distances form the foundation) was also evaluated. Based on the results of such measurements, dynamic characteristics of the shaking table foundation using a single degree of freedom model is estimated. Later the magnitude and the frequency contents of the vibration that was transferred to the soil in distances up to 25 meters from the edge of the foundation (in both vertical and horizontal direction) was also determined. According to the results of this study, the level of transferred acceleration to the soil reduces, rapidly, by distance from the foundation. However, the results of these measurements indicates that, acceleration magnitude in the range of high frequency vibration remains untouched.

Hydrocarbons and petroleum pollutants are considered as one of the most important sources of soil contamination. Designing methods for clearing contaminated areas of these pollutants requires familiarization with the behavior and prediction of their release. In this study, a quantitative model based on finite element and using SEEP / W and CTRAN / W programs was employed, and the variation of hydrocarbon emission trends in a variety of soils under unsaturated conditions has been investigated. Based on the results of the experimental model, it has been shown that the used numerical method can accurately predict the release of pollutants in unsaturated soils. The results of numerical analysis show that the rate of diffusion in soil depth is considerably reduced due to the finer soil degradation. Meanwhile, the main pattern of contamination in the gravel soil is penetration in depth and in the fine-grained soil is longitudinal expansion in soil. Also, with increasing groundwater level, the depth of penetration of pollutants in the sandy soil decreases, while in the range of water depth examined, there is no significant effect on fine-grained soil. In the following, two methods for controlling pollution and preventing its penetration into groundwater resources were evaluated. Based on numerical analysis, the use of walls with more permeable materials than the soil under the source of the pollutant is technically and economically feasible.

Due to shrinkage, evaporation, or atmospheric conditions, small cracks appear in the outer concrete surfaces. These cracks can be repaired by using additives, which may also affect the structure and strengthening process. Concrete hydration may partially contribute to concrete repair. Repair usually occurs in small cracks. If concrete cracks were controlled, ordinary concrete would have somewhat of self-healing characteristic. This study investigated the self-healing effect of concrete at different ages by adding fiber (0%, 1%, and 2% of cement weight) to decrease the crack width, and micro silica (0%, 5%, and 10% of cement weight) to affect hydration. Due to the self-healing characteristic of concrete, compressive strength of concrete is a concern of this study. In fact, this study set out to investigate the self-healing effect on compressive strength recovery after the development of structural cracks. Results suggest that adding micro silica can enhance the rate and degree of self-healing in concrete. However, high micro silica content results in relative reduction of concrete strength as compared to the baseline. Moreover, adding fiber imposes crack closure and enhances self-healing characteristic of concrete. Adding these materials may improve the self-healing compressive strength of concrete, which is induced by compressive strength recovery of concrete.

In this paper, the comparison between the behavior of pile groups with two types of connector plugs into the cap clamped and has been joint and seismic response of pile groups with shear force, axial force, vertical displacement, horizontal displacement of the torque moment in the pile is measured. For this purpose, three-dimensional dynamic finite element software Ansys 3D under earthquake loads in use and the results were compared with each other. Finally, comparing the behavior of pile groups in both study with two types of connector shows a joint connection for minimizing vertical displacement and fixed connection to minimize the axial and shear force and bending moment is right. It means that the fixed connection have a better operation than the joint connection. because the joint connection have a better operation just at the vertical displacement and optimizes it. But fixed connection have a better operation at most of outputs.Keywords: pile, pile cap, dynamic analysis, liquefaction.

In this paper, the seismic performance safety of a concrete gravity dam (Hygher dam) located in Fars Province, Iran, has been evaluated. Probable levels of seismic damages of Hygher dam induced by three levels of ground motions (DBE, MDE and MCE) have been quantitatively estimated according to the USACE guidelines. The methodology is based on the stress demand-capacity ratio (DCR) and the cumulative inelastic duration as two performance indices. Based on the EAGD computer code linear analyses results, it is concluded that the response of the dam at the DBE level (0.34g) will exhibit either no damage or at most minor damages. At the MDE and MCE levels (0.42g and 0.55g), some tensile cracking will occur, but its level is considered acceptable with no possibility of total collapse. According to the proposed performance criteria, the selected ground motions did not produce significant nonlinear deformation in this dam, and so the said guideline did not require nonlinear analysis to be performed.

Coupled steel plate shear wall (CSPSW) is an efficient system to withstand lateral forces, especially in regions with high risk of earthquakes. This system consists of two steel plate shear walls which are linked together with coupling beams at the floor levels. In this article to study the CSPSW behavior, two parameters have been investigated. One is the degree of coupling, which represents the level of interaction between the two piers and the other is the plastic strength of the coupled steel plate shear wall. 12 CSPSW models have been selected which differ in terms of the length and the characteristics of the coupled beam and the height of CSPSW. These models have been analyzed using nonlinear static method. To verify the results, Borello & Fahnestock verified numerical model has been used. The results from the numerical modeling shows that changing the length of the coupled beams, with the same stiffness has a significant impact on the degree of coupling, while it has little effect on the plastic strength of the CSPSW. Additionally, increasing the stiffness of the coupled beams results in an increase of the degree of coupling, as well as an increase of the base shear of CSPSW.