Journal of Hydraulic Structures
Volume:11 Issue: 1, Spring 2025

Today, optimization is very important and necessary in engineering works and it seems necessary in the field of urban runoff and flood management. In this research, a case study of Darakeh River in Tehran as an important links in flood management and runoff conveying is used to reduce the costs of constructing flood conveying routs and water leakage. In the next step, rainfall values are obtained in return periods of 20, 25, 35, 50, 75 and 100 years by using hydrological relationships. Then, the output runoff is extracted by modeling the network in numerical software and the output hydrographs of the created model areentered into SWMM software. In order to present the output results of the SWMM model in a better format, the SWMM results are entered into SSA software. The SSA results are linked into the Harris Hawks Optimization (HHO) algorithm and finally, the construction cost and water leakage functions are optimized. Eventually, the results of HHO are compared with the Particle Swarm Optimization (PSO) algorithm to check the accuracy of HHO. The value of changes for width and height in bridges and channels are compared in two algorithms. As a result, the HHO algorithm reduces the volume of flood and water leakage in different return periods by presenting less cost as compared to the PSO algorithm.

Wharves supported by vertical piles are very common marine structures with suitable seismic responses. Nevertheless, they severely suffer from extensive lateral displacement in both design and service earthquake level state. Conversely, wharves with batter piles have limited displacement, but they are often restricted by numerous standards and guidelines due to the significant seismic base shear and undesirable failure modes such as buckling, pullout, and deck punching. This study aims to assess the efficacy of shape memory alloy (SMA) based dampers in controlling both displacement and seismic base shear within acceptable limits. To achieve this goal, a thorough investigation is conducted on an oil terminal platform, located north of Qesh in Iran, with a water depth of 20m, as a real case study. A structural system consisting of vertical and batter piles equipped with SMA dampers and base isolators is proposed, wherein batter piles were not directly connected to the deck. At first, three common scenarios (vertical piles, combination of vertical and batter piles, and friction dampers) are examined, and then the proposed SMA damper system is comprehensively evaluated and compares with the available solutions. The findings reveal that systems employing SMA dampers exhibit significantly reduced seismic base shear (20% reduction) and lateral displacement (68% reduction) compared to those with vertical piles. Additionally, the lateral displacement observed in systems utilizing SMA dampers falls within the range of those employing batter piles, while the seismic base shear is limited to only 40% of the system with batter piles.

In order to study the characteristics of the different formed free surface vortices at vertical hydraulic intakes, three sets of experiments were conducted. The spiral flow was detected using the Particle Tracking Velocimetry (PTV) measurement technique in three dimensions (3D) by installing two cameras at above and side of the model. The dimensions of model were 2000mm in length, 1300mm in width and 1500mm in height. Through the experiments, extensive data including tangential (Vθ), radial (Vr) and axial (Vz) velocities and their variations with the changing vortex center in different vortex classes, were recorded and analyzed. Using the obtained results, a 3D flow path was drawn for each class of the formed vortex. Moreover, changes in the diameter of the vortex core (Dvo) in the three different classes of vortex were investigated and its changes along the vortex axis were measured. Results showed that the average of Dvo/D (D is the intake diameter) was about 0.14, 0.2 and 0.23 for vortices Class C, B and A, respectively.

Flows in stepped chutes built with gabions have been studied for about four decades and have found applications mainly in small dams and drainage systems. This paper presents a literature review of experimental studies on the subject, especially those that published data and methodologies for designing stepped chutes in gabions. A dimensionless methodology for predicting the main design variables is proposed, and equations were proposed for this purpose. These equations, based on physical principles and statistically supported, involve characteristics of stilling basins of hydraulic jump downstream of stepped chutes formed by gabions and the main quantities related to the design of these hydraulic structures. More than 160 data points were used, each of them involving several parameters of the adopted physical models, making the proposed methodology valid for five different slopes of the downstream face of the stepped chutes. The new equations allow for calculating the length and elevation of the stilling basin bottom. They also allow the determination of the supercritical depth at the basin inlet and the estimation of the height of the continuous end sill of the stilling basin. The proposed equations present strong correlations and adherence to the experimental data in the literature and reveal the missing data about the subject considering the existing literature. In addition, an application example illustrates the use of the developed methodology and compares the present results with those obtained from a methodology available in the literature.

Considering the developments of new accurate constitutive models and numerical methods, a comparison between the classical and modern numerical methods of dynamic analysis of earthfill dams seems necessary. A three steps procedure was followed in this study. First, the accelerations and displacements of a typical homogenous dam were calculated using Sarma, Makdisi-Seed, and Sarma-Ambraseys methods, the results were compared with the results of Quake/W and Slope/W software using both linear elastic and equivalent linear models. Then, a special code was developed to calculate the deformations of a given wedge of the dam body. The studies showed that using linear elastic behavior model, the critical acceleration estimated in classic methods is high and leads to oversized design. However, the more realistic constitutive models give better results. Also, in classic methods the shape of the wedges was unrealistic as it was assumed to pass through the core of the dam, while in numerical analysis it was shown that the critical wedge passes through downstream shell. Therefore, the critical acceleration of wedges was different from the predictions of the classic models, for example it was estimated to be 0.41g in the Ambraseys-Sarma method compared to 0.31g in the linear method for a wedge depth of 0.6h. It was concluded that numerical methods with more realistic constitutive models must be used. Finally, the Kheyrabad embankment dam was analysed using the developed method. It was concluded that the dam would show a permanent deformation of 4.0 cm under scaled Naghan earthquake.

The Makran coastline, a strategic maritime region, has remained understudied regarding its hydrodynamic behavior. This study applies numerical simulations to analyze wave patterns in the northern Gulf of Oman, focusing on wave height (HS), power (P), and mean wave direction (MWD) through Fuzzy Logic transformation and overlaying techniques. Seasonal and annual variations reveal that HS ranges from 0.07 to 1.9 m, peaking during the summer with an average of 0.7 m, while winter and spring exhibit calmer conditions with an average HS of 0.4 m. Wave power (P) shows a marked increase in summer, reaching up to 10.2 kW/m, with an annual mean ranging from 0.02 to 5.3 kW/m. Wave direction shifts seasonally, predominantly from 171° to 247° during winter and spring, and between 189° to 191° in summer and autumn. Spatial analysis highlights intensified hydrodynamic activity in the eastern region, influenced by oceanic conditions and the monsoon, while the western sector remains relatively calmer. Omega-shaped coasts and bays demonstrate more stable conditions, whereas headlands and capes experience significant hydrodynamic intensification. These findings provide critical insights for coastal management and sustainable development, enabling policymakers to balance maritime potential with risk mitigation. By integrating hydrodynamic dynamics into coastal planning, resilient strategies can be established for the sustainable utilization of the Makran region’s resources.