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Partner Journal
Volume 3 : Issue 5, September 2013
Table of Content, 25 September 2013
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An Energy Approach to Static Analysis of a Centrally Loaded Simply Supported Thin Rectangular Isotropic Plate |
Original Article, C38 ABSTRACT:In this paper, the numerical factors for deflection of a centrally loaded all round simply supported thin rectangular isotropic plate are determined using energy approach. The results obtained using energy approaches are compared with those obtained from literature. It is shown that results obtained using energy method are agreed favorably with those of other author serving as the exact solution showing the efficacy of the energy method in the determination of numerical factors for deflection of a centrally loaded simply supported thin rectangular isotropic plate. It is also found that the value of the numerical factors for deflection of all round simply supported thin rectangular isotropic plate is a function of the assumed polynomial function. |
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Neighbourhood Classification and Organization of Informal Settlements Using Development Method of Morris (Case Study: Bonab City) |
Original Article, C39 ABSTRACT:Informal settlement is influenced by unequal global political-economic relationship, weakness of national programs in middle level and urban planning in micro level. Ever increasing expansion of the phenomena lead to the emergence, development and expansion of conflict in the urban soul and body, and creates abnormal biological conditions with dissimilar development indicators that not only questions equitable allocation of resources and services in line with social justice, but challenges sustainable development of urban life. However, any urban planning and designing considers comprehensive content - physical, scientific - practical understanding of urban systems, subsystems and outreach systems in relativist position of space and time; therefore, it is necessary to understand neighborhood and informal settlements based on different physical, business, economic, social, cultural, and infrastructure indicators. In this regard, development method of Morris is used. To investigate neighborhood development, physical, economic, social and infrastructural characteristics of all neighborhoods in Bonab city are studied. Results of the study show there is obvious difference between physical, economic, social and developmental indicators of neighborhoods in Bonab city that lead to inequitable distribution of services and resources. Finally, based on results of Morris development model and neighborhood classification, suggestions and priorities of neighborhood-oriented urban planning and informal settlement organizing are presented. |
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An Investigation of Efficiency and Accuracy of Energy-Based Capacity Spectrum in Estimating the Seismic Demands of Buildings |
Original Article, C40 ABSTRACT:In the conventional methods of pushover analysis, the capacity spectrum is obtained with linking roof displacement to base shear, while this relationship only is meaningful in pushover analysis with load pattern that is proportional to the first mode. In the higher modes, changes of the roof displacement is not proportional to the changes of other stories displacement, and even in some cases roof displacement is decreased with increasing base shear and reverses. Therefore, using the roof displacement for establishing the capacity spectrum in the higher modes is faced with ambiguities. Using the energy method for establishing the capacity spectrum of structure is one of the proposed methods to eliminate these ambiguities. In this method, not only the amount of the roof displacement, but also the amount and the sign of other stories displacements participate in the establishment of capacity spectrum of structure. In this research, the accuracy and efficiency of energy-based capacity spectrum has been studied on two steel moment-frame buildings under different earthquakes for using in different pushover analysis with various load patterns. The results show that using the energy method for establishing the capacity spectrum not only eliminate the existent ambiguities and problems in establishment of capacity spectrum, but also the responses of the different nonlinear static analysis by using the energy-based capacity spectrum instead of the conventional capacity spectrum (based on roof displacement) have better accuracy and efficiency. |
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Equivalent Static Analysis of the Kabud Tower of Maragheh |
Original Article, C41 ABSTRACT:This paper investigates the behavior of masonry materials under lateral loads. The specific structure investigated in this paper is The Kabud Tower which is attributed to Hulagu khan’s mother and is related to Seljuk era in1197 BC (539 Hegira). Since this structure is made of two distinct parts, stone and brick with mortar, modeling of the elements is limited to distinct ways with contact bond in ANSYS. Because the first step for strengthening is detecting of the weak points, the structure was analyses against lateral loads. Concerning the existence of crack on the structure, this structure was modeled on cracked and non –cracked models and then effect of present crack on the behavior of the structure was investigated. |
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Errors Estimation of Different Numerical Integration Techniques on Stiffness Matrix and Stress Intensity Factor in XFEM |
Original Article, C42 Keywords:Gauss Quadrature Integration, SIF ,Stiffness Matrix, Sub Element Rule Integration, Trapezoidal Rule Integration, XFEM |
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An Independent Robust Modal PID Control Approach for Seismic Control of Buildings |
Original Article, C43 ABSTRACT:In this paper, an independent robust modal PID control approach for seismic control of structures is proposed. First, state space equations of the structure are transformed into modal coordinates. Second, the parameters of the modal PID control are separately designed in a reduced modal space. To create a good trade-off between the performance and robustness of the modal controller, the modal feedback gain is determined using genetic algorithms. Then, the feedback gain matrix of the controller is obtained based on the contribution of modal responses to the structural response. Considering four earthquakes and twelve performance indices, the performance of the controller is investigated for an 11-story realistic building equipped with ATMD. Simulation results show that the proposed controller significantly performs better than the LQR in reduction of structural responses. Unlike the LQR, the proposed controller is able to significantly reduce structural responses in strong earthquakes at the cost of demanding a higher control force and external power. Furthermore, it maintains appropriate performance in dealing with model uncertainties. In addition, the proposed controller has several advantages over conventional modern controllers in terms of simplicity and reduction of required sensors to the number of controlled stories. |
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Estimation of Suspended Sediment Load Using Genetic Expression Programming |
Original Article, C44 ABSTRACT:Accurate estimation of suspended sediment load carried by a natural river is important for river engineering and water resources projects. In recent years, using smart systems to increase accuracy of estimating of river sediments are common. In this study were used the Genetic Expression Programming (GEP) in order to estimate suspended sediment load in Sistan River. Root mean square error (RMSE), mean bias error (MBE) and determination coefficient (R2) statistics are used for evaluating the accuracy of the models. GEP is found that scenario 3 with four function and RMSE=0, MBE=2.69×10-4, R2=1 in train period and RMSE=0, MBE=2.4×10-4 and R2=1 in test period are superior in estimating suspended sediment load as the best accurate model. The modeling approach presented in this paper can be potentially used to reduce the frequency of costly operations for sediment measurement where hydrological data is readily available.Also estimation of suspended sediment load using other AI methods such as Particle Swarm Optimization, Tabu Search in Sistan River are suggested. |
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Spatial Analysis of Urban Inequality in Qazvin Province |
Original Article, C45 ABSTRACT:As a descriptive-analytical study, this paper aims to investigate and analyze spatial inequalities among different cities of Qazvin province during 1976-2006, using statistical models and software. Regarding population, social, economic, health, cultural, infrastructural, transportation and communicational indicators in 25 cities of Qazvin province, Qazvin, Abgarm, Narje are most developed, and KhakAli, Sagez Abad, Aavaj, Abgarm, Zia Abad, and Sirdan, are deprived cities, respectively. Coefficient of variance model indicates the most inequality belongs to cultural indicator and the least belong to social indicators. Based on the results of the study, economical factor is more effective on spatial structure of all cities in Qazvin. Moreover, infrastructural and cultural factors are influential in cities of the province. |
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The Effect of Post-Yield Stiffness Ratio on Strength Reduction Factors Due to Ductility with an Emphasis on Iran's Strong Ground Motions |
Original Article, C46 ABSTRACT:Inelastic strength demands can be calculated from elastic strength demands by strength reduction factors. These factors are also called response modification factors which depend on some parameters such as ductility, over-strength, redundancy and damping. The main objective of this study is to determine the strength reduction factor due to ductility for non-deteriorating bilinear single degree of freedom systems which have positive post-yield stiffness or strain hardening for some Iran’s major earthquake records. Compact structural steel sections and some seismic base isolation systems are some examples of mechanical systems with bilinear hysteresis behaviour. In this research, The effect of positive post-yield stiffness ratio is studied for both constant-ductility response spectra or inelastic strength demand spectra and strength reduction factors due to ductility. The evaluation of ductility factor requires large computational efforts. To overcome this problem, the PRISM software was used. A functional form was proposed and parameters were evaluated by the least square error method. This functional form is assumed to be a function of post-yield stiffness ratio, target ductility factor and structural period. For this purpose, the El-Centro, Tabas, Naghan and Abbar ground motions were used. |
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Phosphorus Removal from Aqueous Solutions by Bentonite: Effect of Al2O3 Addition |
Original Article, C47 ABSTRACT:Phosphorus is the main nutrient responsible for eutrophication of aquatic ecosystems; therefore, it is important to develop new processes to remove phosphorus from aqueous solutions. In this research, performance, kinetics, and adsorbing isotherms of Bentonite and Bentonite- Alumina compound (10% Alumina (Al2O3), 90% Bentonite) were investigated. According to the results of this study, the Langmuir adsorption model was best to describe adsorption equilibrium data for Bentonite-Alumina mixture and Bentonite (r2=0.999 for Bentonite-Alumina mixture and r2=0.996 for Bentonite). The Langmuir Isotherm parameters for Bentonite and Bentonite-Alumina were Qm=15.2, 18.1 mg/g and K=4.3, 5.5 L/mg, respectively. Moreover, the Freundlich Isotherm parameters were K=6.6, 9.12 and n=3.05, 3.7, respectively. Bentonite-Alumina mixture was found to more effective for the removal of phosphorus than Bentonite (97% in 140 min in comparison to 90% in 140 min). |
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Runoff Estimation Based on Stochastic Optimization Method |
Original Article, C48 ABSTRACT:Despite widespread use of Curve Number (CN) as main parameter in SCS equations for estimating runoff of basins with limited data, its capability in appropriate estimation of runoff has always been controversial. In this study, ability of CN method has been studied in estimating runoff through the application of a stochastic optimization method and within the framework of SCS equations. In stochastic method, sensitivity of statistical distributions, number of statistical samples and range of CN changes on accuracy of calculations have been studied through the application of Monte Carlo Simulation. The used stochastic method is based on the rainfall and runoff information. For this purpose, rainfall and runoff modeling are first selected and probable distribution functions, governing these events, are specified. Then, rainfall and runoff modeling are produced in different sample sizes within random modeling. Produced samples of rainfall and runoff are evaluated based on the specific criteria and specific runoff modeling is selected. The selective runoffs and number of experimental curves are used in SCS equations, rainfall modeling is calculated and their probable functions are determined. Based on Kolmogrov-Smirnov Test, optimal curve number (CNOPT) is set between produced distribution functions and initial probability distribution function governing rainfall events. Also, average and mean curve number (CNAVG,,CNMEG) has been studied. Statistics of basins representing Kasilian and Emameh (Northen Iran) has been used with the aim of studying efficiency of stochastic method. In Kasilian Basin, the runoffs, calculated through the use of CN OPT, enjoyed the minimum error than observational runoffs. This emphasizes desirable capability of CN method in estimating runoff of the basin but stochastic method was unenforceable in Emameh Basin due to the shortage of rainfall and runoff events. |
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