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Local scouring around sloped bridge piers in steady currents was studied both experimentally and mathematically. The effects of different inclination angles, flow intensities, flow depths, and pier size on local scouring were investigated. The experimental results show that the scouring depth increases with an increase in the values of discharge and pier width. The scouring depth for the sloped piers is smaller than the vertical piers one and the maximum scouring depth continuously decreases as the pier inclination angle increases. Prediction of the scouring depth around bridge piers using analytical models can be utilized in the feasibility studies of different models, and evaluations of the parametric analytical. Therefore, it was tried to model the scouring depth as a function of Froude number, flow intensity, and relative roughness parameters using non-dimensional analysis. The regression analysis based models were introduced to determine the scouring depth at upstream side of the pier using experimental tests data. Step-wise linear regression showed that the value of relative scouring depth has considerably good correlation only with two non-dimensionless parameters of inclination angle and normalized approaching flow depth. In this regard, some linear and nonlinear regression tools were utilized to establish functional relationships between these variables. Statistical indices and residual analyses of the models revealed the suitability of the models. Comparison of the experimental and predicted value of relative scouring depth illustrates that the suggested models can reasonably predict this parameter.

Steel concentrically braced frames (CBFs) and Steel eccentricity braced frames (EBFs) are frequently used as efficient lateral load resisting systems to resist earthquake and wind loads. This paper focuses on high seismic applications where the brace members in CBFs and EBFs dissipate energy through repeated cycles of buckling and yielding. The present study evaluates in detail the design philosophies and provisions used in the United States for these systems. The results of a total of 176 analysis of nonlinear history of seismic behavior of CBFs and EBFs braces have been presented. Notable differences are observed between the performances of the CBFs and EBFs designed using American provisions. The similarities and differences are thoroughly discussed.

In this study, a nonstructural and eco-friendly solution has been used to reduce scouring downstream of screens. Upstream of the screen are stilling basins protected against scouring, but downstream locations are subjected to flow scouring. One of the challenges that the current research brings with it is the process of dispersing nanomaterials. In this research, to achieve its goals, three beds of channels with sedimentary materials, sedimentary materials plus clay, as well as sedimentary materials with a combination of clay and montmorillonite nanoclay have been used. The experimental results show the positive effect of clay and nanoclay on scour depth reduction downstream of the screens. The best performance occurs with the clay and montmorillonite clay mixture. The positive effect of clay and montmorillonite nanoclay mixture for scour length reduction is observed, and by utilizing this mixture, the length of scouring has decreased 33%. Furthermore, by adding clay and montmorillonite nanoclay mixture, the scour depth is reduced up to 39 and 46%, respectively. Utilizing clay and montmorillonite nanoclay mixture has a positive effect on scouring control. It could be very useful for cases such as rivers where bed protection with concrete is not possible.