نشریه مهندسی عمران و محیط زیست دانشگاه تبریز
سال چهل و چهارم شماره 1 (پیاپی 74، بهار 1393)

Nowadays, beside water shortage, we face with mismanagement in water resources. In this situation, optimal water management especially in arid and semi-arid areas is very important. The increase of water demands due to population growth, industrial and agricultural developments was inevitable. On the other hand, due to water resources limitations and principal of sustainability in water management, water allocation, is a very challenging work. Hence, for answering to agricultural, municipal, industrial and ecological demands with high reliability, we need very rigorous programs. The purpose of this paper is to investigate the effect of storage dam on Hesaroo river in Golak area for floodwater collection at raining times and also providing so called demands to recharge the alluvial aquifer, downstream plain and also rich the groundwater. System Dynamic Modelling (SDM) System Dynamic Modelling is a methodology for studying feedback systems. Forrester introduced SDM as a methodology for decision-making in industrial management problems [1]. SDM is extensively used for water resources modelling due to its flexibility, effectiveness in assessing different management options, ease of operation and suitability for encouraging stakeholder involvement [2]. For simulation, first we made a basic demand and supply framework and our model in Vensim is originated from that framework. In this model, all demands, supplies and also groundwater has been considered.Developed model:We identified shortage in groundwater, agricultural and environmental demands as the most important elements in Golak area. For that reason, after making causal loop diagram (CLD), we developed a Stock and Flow Diagram (SFD) for Golak dam. This model includes Golak storage, evaporation from it, groundwater supply, municipal, agricultural, industrial and environmental demands. Because of groundwater crisis in that area, we added a new Stock to model for distribution of floods to enrich the groundwater supply. The proposed system dynamics model was validated by comparing estimated values to historical data. Validation proved the accuracy of our model.3.1. SFD model in VENSIM In order to investigate the effect of distribution of floods for enrichment of groundwater supply, we run the model (Fig.1) and analyze the effects of distribution while all demands are answered. The results show significant increasing in groundwater’s elevation. This study has showed that System Dynamics is a useful decision support tool for the simulation of sustainable water resource management. Results of this study showed the effect of Golak dam on groundwater storage by distribution of floods to enrich the groundwater. According to this paper, this model can use for the implementation of different managing and operational policies on the water resource allocations. Different Scenarios such as altering the river flow due to dry periods and changing in various demands because of growth in population and industry can be simulated and analyzed by this model.

Dynamic Analysis of Dam‐Reservoir Interaction by Euler‐LagrangeApproach Using Perfectly Matched Layer (PML) in Radiation BoundaryReza Tarinejad *, Sajjad PirboudaghiFaculty of Civil Engineering, University of Tabriz, Tabriz, 5166616471 IranReceived: 24 February 2013; Accepted: 09 September 2013Keywords:Dam-reservoir interaction, Euler-Lagrange, Perfectly matched layer (MPL), Radiation boundary, Finite elementmethod A key issue in the seismic analysis of a dam-reservoir system is the accurate and inexpensive modeling of the unbounded reservoir. The Perfectly matched layer (PML) is one of the state-of-the-art boundary conditions, introduced by Berenger for the absorption of radiated boundary waves. In this research,seismic analysis of damreservoir systemis carried out using the PML in the radiation boundary of the reservoir. For this purpose,the numerical implementation of the PML based on the finite element method is presented. A special purpose computer code is developed to carry out the dynamic analysis of the dam-reservoir systems using the MATLAB software. Sensitivity analyses corresponding to the PML layer parameters, the decay function and layer thickness, are carried out to achieve accurate results in less computing time. Coupling of dam and reservoir equations The dam-reservoir interaction is a classic coupled problem, which contains two harmonic differential equations in the frequency domain. Damreservoir analysis by using PML at far end of reservoir A computer code is developed to carry out the seismic analysis of the dam-reservoir interaction system using the PML layer in the radiation boundary of the reservoir. Verification of the developed code is carried out by the comparison of the results using Sommerfeld boundary condition by appropriate length of the reservoir, three times of the dam height, with the results of the previous investigations. Good agreement was obtained in time and frequency domain. Sensitivity analysis with PML’s length (LP), reservoir’s length (LR) and attenuation coefficient (σ*) are performed to achieve accurate results in less computing time. The convergence errors of the dam crest horizontal displacement (L2 error) are indicated versus different parameters in Figs. 1 and 2. The maximum responses of the dam-reservoir system obtained from two kinds of boundary conditions, the optimum PML layer and Sommerfeld, are presented in Table 2. Although the small length of the reservoir is modeled by using the PML layer in comparison with the classic Sommerfeld boundary condition, the results show good agreement for different kinds of responses. The PML was adopted in the radiation boundary of the reservoir in the seismic analysis of the dam-reservoir interaction system and the finite element implementation was presented. A computer code is developed and verified to carry out the dynamic analysis of the interaction system using the MATLAB software. Sensitivity analysis of the PML parameters, PML’s length (Lp), reservoir’s length (LR) and attenuation coefficient (σ*), was performed to achieve the accurate results with less computational time in comparison with the results obtained from the classic Sommerfeld boundary conditions. Results from this analysis demonstrated that for the same accuracy, the PML-type radiation boundary leads to 50% off in time consumption of the analysis compared to the Sommerfeld boundary condition.

In many cases, with entering the floods in the reservoirs of dams, turbidity currents are occurred at the bottom of reservoir. This current is one of agents in sedimentation and reducing the water capacity of reservoirs and useful life of dams. Opening bottom gates is a conventional method of this currents venting and preservation of the useful volume of the reservoir. Sefid-Rud reservoir dam is the largest hydroelectric dam in Gilan which has a lot of sedimentation problems. In this research, advancing the turbidity current in Sefid-Rud reservoir dam was surveyed and the effect of bottom gates of Sefid-Rud dam on venting of turbidity current was evaluated in different scenarios by using Mike3 Model. The Mike3 model Mike3 is a three-dimensional numerical model which has developed by the Danish Hydraulic Institute for simulation of free-surface flows, cohesive/non cohesive sediment transport and water quality using structured or unstructured grids. There are different modules for unstructured grids in Mike3 model. In this research, the hydrodynamic module was used for simulation according to the features of this module. The model based on unstructured grids uses a finite volume method to integrate numerical equations [1]. Reaching time of turbidity current to the dam According to entering flood into reservoir at the same time in beginning of Ghezel-Ozan and Shah-Rud branches, turbidity current reached the dam body through the Shah-Rud branch earlier than Ghezel-Ozan branch and determined the time opening of bottom outlet gates. The results showed that according to entering flood into reservoir at the same time in beginning of Ghezel-Ozan and Shah-Rud branches, turbidity current reached the dam body through the Shah-Rud branch earlier than Ghezel-Ozan and determined the time opening of bottom outlet gates. Modeling results of suspended sediments concentration profile were compared with field data in three cross-sections and were calibrated. High values of deterministic coefficient and low values of error coefficients show the ability of the used model in simulation of turbidity current in Sefid-Rud reservoir dam. Also the optimum operation of bottom outlet gates of Sefid-Rud dam for venting of turbidity current in defined scenarios was studied. The results showed that according to sediment evacuation efficiency and removed sediments weight respect to outflow water volume from reservoir parameters and existence of enough water in reservoir for venting of turbidity current, the best option and optimum operation of bottom outlet gates can be determined.

The bond between concrete and tensile reinforcement is a major problem in RC structures, as far as strength and safety are concerned. Because of the complexity and the effect of a variety of parameters, researchers have not been able to theoretically include all parameters in their solutions for the bond phenomena. This paper proposes an equation for calculating the splice length of lap-spliced concrete beams reinforced with FRP bars. Firstly, equations for displacement modulus and local bond strength of FRP bars are obtained by available pullout test results. After wards, using the local bond strength equation and based on the experimental results of lapspliced FRP reinforced concrete beams, an equation for bond strength of splices is derived. Finally, an equation for splice length calculation is also presented. The splice lengths calculated by the proposed equation are compared with the values predicted by different code provisions and other models. The proposed equation is compared with the existing design equations (ACI 440.1R-06 4] and CSA S806-02 [5]) using a parametric study. According to Fig. 4, in specimens with concrete compressive strength of 28 MPa, the splice length obtained from the proposed and ACI 440.1R-06 [4] equations are almost the same. For specimens with concrete compressive strengths of 41 MPa and 55 MPa, the splice length obtained from the proposed equation is longer than that obtained from ACI 440.1R-06 equation, and as the compressive strength increases, the difference between these two equations increases. As seen in Fig. 4, for specimens reinforced with small diameter bars (db< 22mm), the splice length calculated by the proposed equation is greater than that calculated by CSA S806-02 [5] equation. For the specimens reinforced with large diameter bars (db≥ 22mm) and C/db 1.5, the difference between the values calculated by the proposed equation and CSA S806-02 equation are small.Based on the results of this study, the following conclusions were drawn:1- The proposed equation for determining the local bond strength of GFRP bars showed a good correlation with experimental results. The average ratio value of the experimental to calculated local bond strength obtained by the proposed equation was 1.022 with a standard deviation of 0.138.2- The average of the experimental over calculated bond strength ratios obtained by the proposed equation was 1.09 with a standard deviation of 0.164. These values were 0.649 and 0.187 for the ACI 440.1R-06 guideline. Therefore, ACI 440.1R-06 equation overestimates the bond strength of GFRP bars in splices of beams.3- A simple and practical equation was proposed for determining the splice length in beams with GFRP spliced bars. When compared to the ACI 440.1R-06 and CSA S806-02 codes, the proposed equation is generally conservative.

One of the most important geotechnical issues is problematic soils (dispersive soils, expansive soils, collapsing soils, liquefying soils, soluble soils …) which may affect the constructing projects on these soils and may even cancel them [1]. In this research collapsing soils are studied. A sudden collapse of the land is called collapsing. It is because the strength of the bonding among soil particles no longer exists. Studies have shown the of these soils structure need to be improved before constructing any structures on them [2]. Improvement of these soils with various substances leads to different results. The effect of Polyurethane B with different combination percentages (0.5, 1, 1.5, 2, 3 and 5 weight percentage) on improving the structure of these soils were examined. Polyurethane B is one of the most common elastomerics in engineering which has numerous uses. It has unique characteristics such as high mechanical and wear resistance, flexibility in low temperature, high cutting potential and elasticity and resistance to absorbing water, oils and solvents. The most significant feature of these polymers is that a fixed structure is obtained after reaction. In this research, direct shear test was used with stress control. Vertical pressures of 54.5, 109 and 218 Kilopascals were applied out on specimens. In order to determine the collapsing rate, ASTM D 5333-03 standard criteria were used [3]. The sample was collected from Hamidiyeh Region near Ahvaz city. Atterberg limits, simple shear test and collapsible index experiments were carried out on the specimen to determine some of the physical and geotechnical features of the soil. The results are shown in Table 1. Collapsing tests revealed that by increasing the percentage of additive substance, collapsing index decreases. The value of collapsing index for 0.5, 1, 1.5, 2, 3 and 5 combination percentages were 45%, 58%, 75%, 86% and 92%. After conducting the direct shear test on the soil which was combined with Polyurethane B, it was concluded that the most shear strength can be obtained in 1% combination percentage. In this combination, the value of adhesion and angle of internal friction were increased 27% and 3%, respectively.

A coupling beam is a type of beam for connecting two adjacent shear walls, with a functioning similar to that of eccentrically braced steel frames (EBF). Seismic characteristics of various types of coupled beams such as diagonally reinforced concrete coupling beam (DBCB), steel coupling beam (SCB), composite steel/concrete beam utilising a vertical web shear plate with headed shear (SPCB), and steel beam with a steel fuse link located at mid span of the beam (FCB) are studied (Fig. 1). Pushover analysis has been performed for chosen frames of up to 20 storeys in order to determine reduction factor as a function of overstrength factor, ductility factor and indeterminacy reduction factor. In this research, novel relations have been proposed for calculating reduction factor, which include the effect of the type of soil and height of the structure. Four 5-, 10-, 15- and 20-storey frames with 3 m-high storeys and five spans have been analysed. There are four concrete bending frame spans, each 5 m long, and a 4 m-long span with two coupling core wall, each 1.4 m long, and a 1.2 m-long coupling beam. ETABS code [1] has been used for the design of structural members, pushover analysis, and the determination of overstrength factor, ductility factor and indeterminacy reduction factor by which reduction factor can be calculated. The effect of four different types of soil has been considered. Effect of variable parameters on reduction factor In order to investigate the effect of variable parameters on reduction factor, two types of frames, i.e. intermediate and special bending frames, four numbers of storeys, i.e. 5, 10, 15 and 20 storeys, and four different types of soil, i.e. types I, II, III and IV [2], have been considered. The sequence of member stiffness increase is from coupling beams towards beams, columns and shear walls and it is more pronounced for lower frames. By increasing the height of the frame, the reduction factor calculated by the proposed equations is decreased until it coincides with the value proposed by the Iranian Earthquake Code [2]. For points higher than the coincidence point, reduction factor is on the safe side. For looser soils, the value of reduction factor increases slightly for points lower than the coincidence point and it decreases slightly for points higher than the coincidence point.

Stiffness and strength of a structure are two vital and important parameters. Always designers try to find a method to produce equilibrium between these. Recent decade's investigations focused on optimization of stiffness. In these structures we can not ensure that structure has adequate strength or not. So survey of strength is a very important topic. To maximize the strength we have to minimize the maximum stress of the structures. In all of old researches stress is a constraint rather than objective in the optimization processes. Although this may guarantee the stress within a prescribed constraint (generally less than some limit), it cannot always make the maximum stress a minimum. In optimization of a single criterion (stiffness or strength), other criteria can not be maximum. Hence, multicriteria optimization is a logical method. In this research, we use Evolutionary Structural Optimization (ESO) method for size optimization to maximize stiffness and strength of structures. To obtain global criteria, we use weighting method and weight factors. A linear combination of both weighted criteria produces global criteria. In order to calculate suitable weight factors for any structure that we use in research, we examined different value of these and optimize the structures for this values. By comparison of the results, we select the best value of weight factors that can optimize strength and stiffness of the structure. This research has two important a) Thickness distribution at different positions of structure according to stiffness or strength alone does not optimize other criteria in order to have a structure with optimum stiffness and strength; we have to optimize two criteria simultaneously.b) Programming ESO method for multicriteria optimization is very easy and simple. We used a MATLAB code for the FE analysis and a loop for repeating the optimization procedure. Optimization of stiffness alone does not lead to a structure with adequate and vice versa. In order to have a structure with adequate stiffness and strength, we have to optimized the these criteria simultaneously. ESO is a very easy method for multicriteria optimization and programming. We optimize topology of the structures in this research.

Formaldehyde is used in many industrial activities such as adhesives, resins, paper producing and pharmaceutics industries. Due to formaldehyde toxicity for microorganisms, aerobic biological methods were less studied for its treating. Chemical and anaerobic biological methods are often applied for treating wastewaters containing formaldehyde. Recently, some methods such as Fenton and photo-Fenton, photo catalytic degradation, combination of chemical-biological and anaerobic-aerobic biological have been investigated. In this research, formaldehyde removal efficiencies using aerobic biological treatment systems including moving bed biofilm reactor (MBBR) and sequencing batch airlift reactor (SBAR) were compared.Temperature, pH, and dissolved oxygen were adjusted every 6 hours for preparing suitable condition for microorganisms activity. Mixed liquor suspended solid and sludge volume index were measured daily. COD, BOD5, granular diameter, and velocity settling were used for illustrating reactors situation. All of the experiments were accomplished in accordance with the instructions presented in the "Standard Methods for the Examination of Water and Wastewater" [1]. After investigating all methods, the best one was selected regarding to the laboratory facilities. Removal efficiency was determined using COD results. COD removal efficiency The results showed both systems can be used for treating formaldehyde wastewater in low concentrations. The most removal efficiencies were 100% that occurred in concentration of 100 mg/L (Fig. 2). The results of this research in pilot scale showed both systems were capable in removing formaldehyde from wastewater in concentration of less than 300 mg/L with a 24-hour retention time. SBR and MBBR systems can be used as pretreatment units for the treatment of formaldehyde CODs more than 500 mg/L. 5.

Today, the cement industry is one of the most air polluting industries in the world. With over seven decades of experience in the cement industry with a total annual production capacity of approximately seventy million tons, Iran is the largest producer of cement in the Middle East. Ilam cement factory is one of the major cement manufacturers in Iran. Hence in this study, owing to the importance and role of contaminants from the plant, appraisal of the emissions contribution in addition to other factors has been discussed. For this purpose, in the first place, the flow parameters and the suspended particles from stack outlet have been measured using appropriate equipment [1]. Then by applying AERMOD software, diffusion and dispersion of suspended particles in the surrounding area has been modeled [2]. Because of entering the suspended particles from the west of the country to the study area, in order to determine and evaluate the factory’s share of total available particles, the amount of particles in the atmosphere is measured at four points around the plant using SKC pump. By subtracting the measured amount of particles resulted from modeling from measured ones using SKC pump, Ilam cement factory's share percent, compared to other sources of pollution in the region, can be estimated 3]. Measuring the output suspended particulates from the stack and surrounding environment To achieve the research objectives, primarily the output suspended particles from the cement factory’s stacks should be measured by sampling. Thus output gas speed, temperature and pressure have been measured by applying the KIMO device and suspended particles have been assessed by using WESTECH. Table 1 shows the location of stacks in Cartesian coordinate system and local coordinate system [4]. AERMOD run Table 2 shows the maximum concentration for mean time at 1 hour, 3 hours, 8 hours, 2 hours, 1 month and 1 year. By comparison of results in a functional state (enabled simultaneously for all sources) which is presented in Table 2, whit proposed limit values for particulate emissions, it is well received that even though all of the plant sources are active, the maximum concentration for mean time at 24 hours and 1 year are much lower than clean air standards. As the satellite image (Fig. 1) shows, some areas such as Sarabeleh, Ilam, and Kovar are less affected by output particle emissions from cement plants. Although in comparison with other areas, Ivan district is more affected by pollution from these sources, it does not meet the limit proposed by the Environmental Protection Agency. According to the presented results, the maximum concentration of particles originated from Ilam cement plant in all points is equal to 1 microgram per cubic meter occurred at a distance of 8900 m and 5300 m along the north-east direction.