توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱THE ANALYSIS OF CHLORIDE DIFFUSION COEFFICIENT IN CONCRETE BASED ON NEURAL NETWORK MODELS
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۸
Chloride diffusion is one of the major causes of deterioration of concrete structures. A large amount of research has been conducted to study the chloride diffusion of concrete, both experimentally and theoretically. Because chloride diffusion experiments are time consuming, it is desirable to develop a model to predict the chloride profiles in concrete. This paper studies the feasibility of using a
neural network as an adaptive synthesizer as well as a predictor to meet such a requirement. So some neural network models to predict chloride diffusion coefficient were made. The models were trained by results of chloride profile experiments. Input parameters were water to binder ratios, the amount of silica–fume and environmental condition of samples. The output parameter was chloride diffusion
coefficient. Neural network models are multi layer Perspetron models and they differ in the number of hidden layers and neurons. To control the accuracy of the model, an ANNs model was made and the result of the model was compared with test specimens. The result demonstrates that both neural network models have the ability of predicting the chloride diffusion coefficient with good accuracy.<\div>

۲The Effect of Vertical Component of Earthquake on Continuous and Monolithic Frame Bridges
نویسنده(ها): ،
اطلاعات انتشار: Journal of the Structural Engineering and Geotechnics، دوم،شماره۱، ۲۰۱۲، سال
تعداد صفحات: ۶
Performance of structures during recent earthquakes shows that the effect of vertical component of earthquake (VCE) could be considered as one of the main causes of bridges collapse. In most of bridge design codes, for seismic analysis of bridges, VCE is not taken into account or a distinguished method isn’t presented for assessment of VCE. In the present work, the effect of VCE on two existing bridges, one with continuous deck and the other with monolithic frame system, was studied. The first model consisted of a pre–stress bridge in which the superstructure was connected rigidly to piers. The super structure consisted of 3 spans with length of 16, 48 and 16 m. The end of side slabs was put on abutments. The second model was a bridge with steel deck and concrete piers. The bridge superstructure was composed of I girder beams and in–place concrete slab. The beams were placed on 3 piers located 24 m far from each other, continually. In both models, the effect of VCE was studied considering the 3 acceleration of Tabas, Northridge and Kobe earthquakes and using linear and nonlinear time history and spectrum analysis on 3D models. In each analysis, the model was analyzed considering the 3 component and 2 horizontal components of earthquakes separately. The ratio of the difference of results in two analyses to the result of bridge response under its weight (DL) was compared. Through this method the amount of VCE effect on affected elements (according to statistical system of bridge) was found out.
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