Arch dams are often preferred in narrow, high valleys due to their distinctively high and curved geometries, making them particularly effective for water retention. Consequently, assessing the seismic performance of these critical structures is essential. The presence of gallery openings within arch dams further heightens research interest, especially in regions of high seismic activity. This study presents a detailed three-dimensional (3D) numerical failure analysis of the Ermenek Dam, one of Turkey's largest arch dams. Using the finite-difference method, a 3D model is constructed, incorporating four distinct D-shaped gallery openings within the dam body. These openings are integrated into the model using specialized FLAC3D fish functions. To enhance simulation accuracy, the foundation is proportionally extended along the dam's base and sides. The Burgers creep material model is applied to assess both creep behavior and seismic response within the concrete body and foundation. Non-reflecting boundary conditions are imposed on the model boundaries to create realistic constraints. Numerical analyses are conducted on various gallery dimensions, evaluating 28 distinct geometries under ten different strong ground motions. The seismic analysis results indicate that damage may occur within the dam body when gallery height exceeds twice its width. Therefore, careful consideration of the geometrical dimensions of gallery openings is highly recommended during the modeling and analysis of arch dams.

This research investigates the mechanical behavior of high-density polyethylene (HDPE) pipes reinforced with composite materials, including Boron/epoxy, Carbon/epoxy, and Glass/epoxy. The study examines the effects of reinforcement position (external, internal, and central) and fiber orientation on stress distribution under simulated load conditions. Using finite element analysis (FEA), the research aims to identify the most effective reinforcement strategy for enhancing the mechanical properties and performance of HDPE pipes. Comparative analysis of stress and displacement data across various configurations offers insights for optimizing the design and application of composite reinforcements in HDPE structures.

The paper focuses on the free vibration analysis of Functionally Graded (FG) beams under various boundary conditions, accounting for the presence of porosity. The effect of different porosity distribution rates is also investigated by employing a newly modified power law formulation to adjust the material properties in the thickness direction of porous FG beams. The displacement model used in this formulation is based on the higher-order shear deformation theory (HDT). Utilizing Hamilton's principle, the governing equation for the free vibration analysis of FG beams is derived. A comprehensive comparative study is conducted, comparing the results obtained with other existing theories. The findings from this comparative analysis, using the state space approach, provide valuable insights into the vibration behavior of FG beams. Analytical solutions are presented to explore the impact of porosity distribution rates, volume exponent, slenderness ratio, and boundary conditions on vibration characteristics. Numerical examples demonstrate that these key parameters significantly influence the vibration response of FG beams.

This study deals with the strengthening of rectangular masonry columns with precast Engineered Cementitious Composites (ECC) system to enhance the axial compressive strength of columns. Masonry columns of 230×230 mm cross-section (b×d) and 700 mm height were cast using locally available burnt clay bricks. These rectangular masonry columns were strengthened with precast ECC sheets. In this method, precast ECC sheets bonded to the rectangular columns without making round edge with proper utilization of strength of the confinement materials. The size of precast ECC sheets depending upon the strength required of the column. In this study, ECC sheets of thickness 25 mm, 35 mm, and 40 mm were used for strengthening of masonry columns. These strengthened and unstrengthened masonry columns were tested for under pure axial compressive load through Universal Testing Machine (UTM). The compressive strength of strengthened masonry columns is increased significantly with precast ECC sheets. This study demonstrates the effectiveness of ECC precast system for strengthening of rectangular masonry columns without making round edge with proper utilizations of the confinement. Moreover, design equations for strengthening of rectangular masonry columns with precast ECC sheets were derived. The design equations were derived based on experimental results. These newly developed design equations would be useful for rehabilitation and strengthening of old/deficient masonry columns.

The flexural responses under different loading of self-prepared partially biodegradable hybrid composites comprising an animal-based (human hair) fiber, a plant-based (Luffa cylindrica) fiber, and incense stick ash (ISA) filler have been first time investigated. These composites were fabricated in-house using an Ultrasonicator-assisted hand lay-up technique, incorporating epoxy resin as the matrix and varying ISA filler weight ratios from 0 to 20 wt.% in steps of 5 wt.%. Firstly, the density, and elastic properties through the non-destructive Impulse Excitation Technique (IET), micro-hardness, strengths under tensile, bending, and impact loading are obtained and the surface morphology of fractured surfaces is studied. Subsequently, finite element (FE) analysis using a simulation model in ANSYS is employed to acquire the tensile and flexural strength. Then, a higher-order nonlinear FE model was developed to compute static responses under various loads (point load, sinusoidal line load, uniform line load, uniform load, and sinusoidal load). The model's validity was confirmed through lab-scale experimentation. The composite with 10 wt.% ISA showed the best overall tensile, bending, and shear properties, while the 20 wt.% ISA composites exhibited the highest flexural strength and micro-hardness. Additionally, composites with 10 wt.% ISA, higher aspect ratio, and lower thickness ratio demonstrated significant resistance to deflection under static loading.

Using a modified Green-Lindsay model, the issue in a nonlocal rotating fiber-reinforced thermo-elastic solid is examined. A formula for the analytical treatment of physical fields is produced by introducing the normal mode analysis. A comparison is made between physical fields for various values of the nonlocal parameter, an empirical material constant, inclined load, and rotation. Rotation, inclined load, an empirical material constant, and the nonlocal parameter all have positive effects on the physical variables. When a nonlocal fiber-reinforced thermoelastic solid is swapped out for a thermoelastic one, this approach still holds true. Normal mode analysis applied to a wide range of problems in hydrodynamics and thermoelasticity. It is also found that the modified Green-Lindsay theory is more efficient in determining the wave propagation phenomenon.

This work presents a full-scale study of the structural behavior of nanoparticles reinforced nanocomposite porous beams under sinusoidal transverse dynamic force. Application of the Mori-Tanaka method for the assessment of the effective properties of the nanocomposite material takes into account the structure of nanoparticle arrangement as well as their interaction with the pores in the matrix. Consequently, the structural transverse behavior of the beams is modeled using Aydogdu shear deformation theory (ASDT) that provides a more accurate deformation extended through a refined shear deformation framework. By integrating the nonlinear strain displacement relations of the component using energy methods and Hamilton's principle, the governing equations are derived which incorporates the interactional and dynamic behavior of the structure. The displacement response of the beams is determined by using the Ritz method for the dynamic analysis of the structure. This paper establishes the impact of a number of key variables on the time varying behavior of nanocomposite porous beams. Among them are the volume concentration of nanoparticles, porosity, effects of the localized aggregation of nanoparticles, geometric characteristics of the beams, and the boundary conditions. The findings also show that an increase in the percentage volume fraction of nanoparticles reduces the dynamic displacement, proving the durability offered by nanoparticle reinforcement for structural applications. Furthermore, the effects of porosity and nanoparticle agglomeration as well as design parameters on the dynamic behavior of the developed material are also investigated.

Control of deflections is more important in the design of reinforced concrete beams. Best estimation of ultimate deflection is the key to better control of failure. The moment-area theorem is a simple method used to predict the deflections of reinforced concrete (RC) beams. This research uses the moment-area theorem to calculate yield and ultimate deflections of RC beams under mid-span and two-point loads. The study compares various models of plastic hinge length to predict ultimate deflection of RC beams. Experimental results from 33 RC beams with normal and high strength concrete were used to evaluate the performance of the models. The results showed that Panagiotakos and Fardis (2001) model provided the best predictions for RC beams under mid-span load and two-point loads with concrete strength over 70 MPa, with errors less than 20%. However, plastic hinge length can be neglected for RC beams under two-point loads with concrete strength less than 70 MPa, with errors less than 25%.