Applied Mechanics and Materials Vol. 935

Abstract: Foundation engineering has large challenges with weak and loose soil, especially sandy soil, which has low shear strength and high compressibility. as known used pile raft to reduced excessive settlement, differential settlement, and to increase bearing capacity of the soil to carrying the loads from super structure. The benefit of use combined (raft piles) to improved load distribution and, increase bearing capacity and enhance stability. It is depending upon many influencing factors the load distribution mechanisms, the pile number, the space between piles and on the pile position. Geopolymers are inorganic formed by the reaction of aluminosilicate materials with alkaline activator. To produce geopolymers, two essential conditions must be fulfilled: the presence of source material abundant in Silicon (Si) and Aluminium (Al), and the addition of an alkali activator, such as sodium/potassium hydroxide..it has several advantage than other traditional soil stabilization method, which increased the soil's load-bearing capacity, enhance the soil properties. This study aims to review the studies of previous researchers and their practical and theoretical findings regarding the use of geopolymers as stabilising agents and pile raft to improve the soil's resistance properties.

Abstract: In order to improve the mechanical performance and sustainability of road rehabilitation operations, this research sought to examine the effects of adding sugarcane bagasse ash and polyester fibers to Babylon soil on certain geotechnical parameters. Throughout the course of the experiment, soil was amended using ash alone, with and without polyester fibers, and finally with a mix of the two additives. Particularly, the results demonstrated a considerable improvement in the soil's surface bearing capacity, unconfined compressive strength, and ideal moisture content. The maximum dry density dropped even more, as one would anticipate when dealing with less dense materials than thick soil particles. The study indicates that a 20% polyester to 15% ash ratio is the optimal ash to polyester ratio. This study adds to the growing body of information suggesting that using recycled materials might enhance soil behavior. If this holds, it may reduce environmental damage by allowing newly constructed infrastructure in areas with poor soil to be replaced with recycled materials.

Abstract: This study applies Life Cycle Assessment (LCA) using OpenLCA software in accordance with ISO 14040/14044 standards. A two-story school building was modeled with reinforced concrete and structural steel systems, both designed using ETABS. The study looks at a two-story school building over several phases, such as getting materials, making them, building them, using them, and then getting rid of them. Key performance indicators such as carbon emissions, energy consumption, recyclability, and construction waste are analyzed. Results reveal that concrete structures emit 27% less CO₂ and consume 55% less energy than steel systems, though steel offers superior recyclability (98%). The results show that steel structures may be recycled and used again and again, whereas reinforced concrete uses substantially less energy and carbon. The study proposes the use of hybrid systems that combine concrete slabs and foundations with steel superstructures to actualize these results. It also proposes employing materials that are good for the environment, such fly ash and recycled aggregates, and establishing national databases to assist people choose products. These suggestions are a practical way to get Iraq to embrace green building laws and practices.

Abstract: This study presents a methodology for predicting structural damage in a concrete and steel bridge using acceleration signal processing and artificial intelligence techniques. Structural vibrations were recorded continuously for 24 hours using five LARA (Low-cost Adaptable Reliable Anglemete) triaxial sensors located on the metal beams under the bridge, capturing data in three axes. The signals were normalized in order to be able to have a fairness of accelerations in the 3 axes and processed through a Convolutional Autoencoder (CAE), which achieved a signal reconstruction fidelity of 97.22%, enabling the generation of realistic synthetic data. To evaluate the separability between real and synthetic signals, a Domain-Adversarial Neural Network (DANN) was applied, successfully classifying both domains. Subsequently, K-Means clustering was performed on the compressed latent space, identifying three distinct structural states: healthy, transitional, and anomalous, with a silhouette coefficient of 0.8947. Notably, Sensors 2 and 4 were grouped into the anomalous cluster, indicating potential localized structural degradation. Finally, a Temporal Convolutional Network (TCN) was implemented to predict the future structural condition based on sequences of latent features. The model achieved an overall accuracy of 85.29% and an F1-score of 0.9954 for transitional states, demonstrating its effectiveness in anticipating early structural changes and reinforcing the potential of the proposed methodology for real-time, predictive bridge monitoring applications.

Abstract: This study employs hydrogen permeation tests, slow-strain-rate tensile tests, and Charpy impact tests to investigate how the welding process and PWHT influence hydrogen diffusion behavior and hydrogen embrittlement susceptibility of welded joint. The research results indicate: The microstructure of all regions of the welded joint consist of granular bainite, MA islands, and precipitated carbides, carbides are mainly M₂₃C₆, M₇C₃, M₂C, and M₆C types. These carbides act as irreversible hydrogen traps and are the primary reason for the reduced hydrogen diffusion coefficient in the material. The heterogeneous microstructure of the weld metal causes direction-dependent hydrogen diffusivity. PWHT also influence hydrogen embrittlement susceptibility. The findings of this study can provide theoretical guidance for optimizing welding procedures in the fabrication of hydrogenation reactors.

Abstract: This study addresses the increasing occurrence of sinkholes in northern and eastern Saudi Arabia, driven by soluble karst geology and unsustainable groundwater extraction. The primary objective is to understand the underlying mechanism of sinkhole formation and propose targeted mitigation strategies. By integrating geological, geophysical (ERT, GPR, microgravity), and hydrological data from previous studies, the research identifies key subsurface features and groundwater conditions contributing to sinkhole development. The results reveal that sinkhole formation is primarily governed by cover-collapse processes, strongly associated with aquifer over-extraction, low-resistivity anomalies, and irrigation-induced saturation. Groundwater declines of 2.5–3 m/year, along with acidic and saline conditions, further accelerate karst dissolution. The study concludes with a three-part mitigation framework: sustainable groundwater management, engineered stabilization of high-risk cavities, and an integrated early-warning system using geophysical monitoring and InSAR. These findings offer a practical roadmap for managing sinkhole hazards in arid karst environments.