Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 4 Articles
Cold-formed steel frames (CFS) are popular all over the world. In this study, we have investigated 112 frames with different bracing\narrangements and different dimensional ratios with different thicknesses of sheathing plates under cyclic and monotonic loading\nusing Finite Element Nonlinear Analysis.We also evaluated seismic parameters including resistance reduction factor, ductility, and\nforce reduction factor due to ductility for all specimens. On the other hand, we calculated the seismic response modification factor\nfor these systems. The maximum modification factor among shear wall panels with sheathing plates related to GWB (gypsum wall\nboard) specimen with thickness of 15mm was 5.14; among bracing specimens in bilateral bracing mode related to B sample was\n3.14. The maximum amount of resistance among the specimens with bilateral (2-side) bracing systems belongs to the specimen C\n(2-side double X-bracing) with the dimension ratio of 2 (4.8m Ã?â?? 2.4 m) and resistance of 305.60 kN and also among the shear wall\npanels with sheathing plates, it belongs to DFP (douglas fir plywood) with a thickness of 20mm and resistance of 371.34 kN....
Concrete cracking strength can be defined as the tensile strength of concrete subjected to pure tension stress. However, as it is\ndifficult to apply direct tension load to concrete specimens, concrete cracking is usually quantified by the modulus of rupture for\nflexural members. In this study, a new direct tension test setup for cylindrical specimens (101.6mm in diameter and 203.2mm in\nheight) similar to those used in compression test is developed. Double steel plates are used to obtain uniform stress distributions.\nFinite element analysis for the proposed test setup is conducted. The uniformity of the stress distribution along the cylindrical\nspecimen is examined and compared with rectangular cross section. Fuzzy image pattern recognition method is used to assess\nstress uniformity along the specimen. Moreover, the probability of cracking at different locations along the specimen is evaluated\nusing probabilistic finite element analysis.Theexperimental and numerical results of the cracking location showed that gravity effect\non fresh concrete during setting time might affect the distribution of concrete cracking strength along the height of the structural\nelements....
Doubtlessly the first step in a river management is the precipitation modeling over the related watershed. However, considering\nhigh-stochastic property of the process, many models are still being developed in order to define such a complex phenomenon in\nthe field of hydrologic engineering. Recently artificial neural network (ANN) as a nonlinear interextrapolator is extensively used\nby hydrologists for precipitation modeling as well as other fields of hydrology. In the present study, wavelet analysis combined with\nartificial neural network and finally was compared with adaptive neurofuzzy systemto predict the precipitation in Verayneh station,\nNahavand, Hamedan, Iran. For this purpose, the original time series using wavelet theory decomposed to multiple subtime series.\nThen, these subseries were applied as input data for artificial neural network, to predict daily precipitation, and compared with\nresults of adaptive neurofuzzy system. The results showed that the combination of wavelet models and neural networks has a better\nperformance than adaptive neurofuzzy system, and can be applied to predict both short- and long-term precipitations....
Selection of urban bypass highway alternatives involves the consideration of competing and conflicting criteria and factors, which\nrequire multicriteria decision analysis. Analytic hierarchy process (AHP) is one of the most commonly used multicriteria decision\nmaking (MCDM) methods that can integrate personal preferences in performing spatial analyses on the physical and nonphysical\nparameters. In this paper, the traditional AHP is modified to fuzzy AHP for the determination of the optimal bypass route for\nEldoret town inKenya.ThefuzzyAHPis proposed in order to take care of the vagueness type uncertainty encountered in alternative\nbypass location determination. In the implementation, both engineering and environmental factors comprising of physical and\nsocioeconomic objectives were considered at different levels of decision hierarchy.The results showed that the physical objectives\n(elevation, slope, soils, geology, and drainage networks) and socioeconomic objectives (land-use and road networks) contributed\nthe same weight of 0.5 towards the bypass location prioritization process. At the subcriteria evaluation level, land-use and existing\nroad networks contributed the highest significance of 47.3% amongst the seven decision factors. Integrated with GIS-based least\ncost path (LCP) analysis, the fuzzy AHP results produced themost desirable and optimal route alignment, as compared to the AHP\nonly prioritization approach....
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