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Finite element evaluation of ultimate capacity of strip footing: assessment using various constitutive models and sensitivity analysis Abstract Finite element method can be used for computing bearing capacity of shallow foundation with irregular geometry resting on variable subsoil. It is necessary to quantify the parameters affecting the ultimate capacity of footing. This paper presents the results of finite element (FE) analysis of the ultimate failure load of a rough base rigid strip footing resting on c-ϕ soil. The soil is assumed as linear elastic perfectly plastic with Mohr–Coulomb failure criterion and non-associative flow rule. Sensitivity analysis is carried out to examine the ultimate capacity of strip footing considering the strength parameters (c′, ϕ′, and ψ), width of strip footing (B), unit weight of soil (γ), surcharge (q) at the base level of footing, and the deformation parameters (E and ν) as the variables. The study also examines the effect of different material models on the ultimate capacity of the strip footing. The material models considered are Mohr–Coulomb (MC) model, Hardening Soil (HS) model, Hardening Soil model with small-strain stiffness (HSsmall), and Soft Soil (SS) mode-l. It is found from the results of FE analysis that the ultimate load of the strip footing is dependent on the strength parameters, width of footing, unit weight of soil, and surcharge at the base level of the footing. The ultimate capacity is independent of the deformation parameters and will remain almost same corresponding to the material models like MC, HS, HSsmall, and SS. The FE results are compared with the analytical solutions of Terzaghi and Meyerhof. Based on the study, a few suggestions are given in regard to the FE analysis of geotechnical stability problems to obtain the quick results. منبع @civilbest - capacity of strip footing.pdf

The Portion of the Influent Parameters on Adaptation Length in Sediment Transport in Numerical Models Original Article, B36 Fuladipanah M,Majediasl M. Journal. Civil Eng. Urban. 2(6): 202-206. 2012. ABSTRACT:River flow and sediment transportation are two phenomena, which are taken place in alluvial streams. The complexity of the simulation of this phenomena have been caused numerous numerical models which are consists of different parameters. The un-equilibrium nature of sediment transport has been caused using un-equilibrium predictor. Adaptation length is one of the most important parameters in this type of equations, which is function of four parameters: flow depth, flow velocity, adaptation coefficient, and sediment fall velocity. Determining of sensitivity level of four mentioned parameters is discussed in this paper. The FAST technique, which is variance based sensitivity method, was applied in this research. According to the results, the first order FAST based sensitivity indices, explain 81.42% of the total variance, i.e., the result of this technique is acceptable. Results showed that sediment fall velocity has the most parameter, which must be measured with high accuracy. In addition, it was found that sediment particle properties are more effective than flow properties. Keywords:River, Sediment, Adaptation length, numerical models, sensitivity analysis. منبع: [Hidden Content] دانلود: [Hidden Content],%20B%2036%20202-206.pdf JCEU, B 36 202-206.pdf

Sensitivity Analysis of Movable Bed Roughness Formula in Sandy Rivers Original Article, B33 Fuladipanah M,Majediasl M. Journal. Civil Eng. Urban. 2(5): 187-190. 2012. ABSTRACT:Sensitivity analysis as a technique is applied to determine influential input factors on model output. Variance-based sensitivity analysis method has more application compared to other methods because of including linear and non-linear models. In this paper, van Rijn’s movable bed roughness formula was selected to evaluation because of its reasonable results in sandy rivers. This equation contains four variables as: flow depth, sediment size, Bed form height and Bed form length. These variable’s importance was determined using the first order of Fourier Amplitude Sensitivity Test. Sensitivity index was applied to evaluate importance of factors. The first order FAST based sensitivity indices test, explain 90% of the total variance that is indicating acceptance criteria of FAST application. More value of this index is indicating more important variable. Results show that bed form height, bed form length, sediment size and flow depth are more influential factors with sensitivity index: 32%, 24%, 19% and 15% respectively. Keywords:Sensitivity Analysis, Variance, Movable bed roughness formula, Sandy River. منبع: [Hidden Content] دانلود: [Hidden Content],%20B%2033%20187-190.pdf JCEU, B 33 187-190.pdf