Current Issue : April-June Volume : 2024 Issue Number : 2 Articles : 5 Articles
Machine learning (ML) algorithms are increasingly applied to structure health monitoring (SHM) problems. However, their application to pile damage detection (PDD) is hindered by the complexity of the problem. A novel multi-sensor pile damage detection (MSPDD) method is proposed in this paper to extend the application of ML algorithms in the automatic identification of PDD. The time-series signals collected by multiple sensors during the pile integrity test are first processed by the traveling wave decomposition (TWD) theory and are then input into a hybrid one-dimensional (1D) convolutional and recurrent neural network. The hybrid neural network can achieve the automatic multi-task identification of pile damage detection based on the time series of MSPDD results. Finally, the analytical solution-based sample set is utilized to evaluate the performance of the proposed hybrid model. The outputs of the multi-task learning framework can provide a detailed description of the actual pile quality and provide strong support for the classification of pile quality as well....
Adhesives and metallic fasteners play a pivotal role in the domain of engineered wood products (EWPs). Nevertheless, owing to their origins in petroleum, adhesives can pose environmental hazards, whereas metal fasteners can complicate end-of-life disposal and reusability. Nonetheless, a resolution emerges in the form of dovetail massive wooden board elements (DMWBEs), characterized by their pure wood composition and absence of adhesive metal connections. The existing literature pertaining to DMWBEs has predominantly focused on inadequate structural analysis and model testing of connection specifics rather than appraising the efficacy of a structural member, such as a floor slab. This article presents a comparative analysis between a DMWBE and a correspondingly sized cross-laminated timber (CLT) panel, focusing on their respective airborne sound insulation capabilities. Experimental samples of model scale with dimensions of 200 mm thickness, 1160 mm width, and 1190 mm length were employed for both CLT and DMWBE. The evaluation of airborne sound insulation performance was conducted in accordance with ISO 10140-2 standards. The findings underscored the superior performance of DMWBE (Rw = 43 dB) in contrast to CLT (Rw = 40 dB) concerning airborne sound insulation efficacy. Additionally, the damping of the panel increased due to the different composition of the DMWBE, as evidenced by a higher measured total loss factor (TLF) compared with CLT....
The carrying capacity for vertical loads of well-maintained masonry arch bridges is reasonably high. This might not be the case for horizontal loads, the effects of which have not been the subject of extensive research aside from seismic occurrences. Arch bridges crossing rivers are subjected to sudden horizontal loads, due to river torrents, carrying debris from higher grounds. The magnitude of these horizontal loads is similar to those of coastal waves and debris; however, their effect on these structures has yet to be explored in detail. The narrow and high Devil’s Bridge across the Arda River (BG) and the wide, low Candia Viaduct across the Sesia River (I) were chosen as examples. Both are strongly exposed to fast-washing flow in the river during spring. FE simulations show that the impact of the rapidly rising river water influences the general stability, while the effect of debris mainly causes local damage. The results exhibit that tall, slender masonry arch structures fail due to the brittle fracture of the material, followed by the shear failure of a pier body. In contrast, lower and wider viaducts fail due to exaggerated tensile cracking in the upstream parts of a pier and the associated increasing pressure at its downstream parts....
The estimation of earth pressure is crucial in the design of retaining structures. The evaluation of vertical retaining walls has been well studied within the framework of the differential flat element method in prior investigations, in which the vertical stress and maximum principal stress are assumed to be uniformly distributed. Inclined retaining walls have been successfully adopted in excavation engineering. Due to the inclination of retaining walls, the maximum principal stress direction rotates approximately parallel to the inclined wall back, which affects the active earth pressure on the walls. This paper provides an analytical solution to evaluate the active earth pressure on inclined retaining walls. A numerical model is first established to analyze the characteristics of the principal stresses and vertical stress distribution of soil behind walls with various inclination angles. An idealized vertical stress field containing two zones is developed, and a hyperbolic function is proposed to illustrate the distribution of vertical stress at various depths. Subsequently, the relationship between the nonuniform characteristics of the vertical stress and normal stress acting on a differential flat element is established based on a circular stress trajectory. The active earth pressure along the inclined wall is then obtained based on the balance of the forces on the differential elements. The predicted data from the proposed analytical solution are compared with the previous experimental, numerical, and theoretical results with excellent agreement, demonstrating the accuracy of the proposed method....
Fixed offshore platforms are structures of steel or concrete located in the middle of the sea used to export oil, trade, or military. These are designed to withstand all types of weather and dynamic loads. The response was very high under applied these loads. This paper includes a proposal to apply a new isolation system to be placed in different places on the offshore platform to reduce vibrations from high water waves. Three cases that be used, fixed-based (column connect directly to the pile), isolation system in the pile head (isolation between column and pile), and isolation system in the pile head and the middle of columns. The dynamic movements in waves were simulated using ABAQUS programs. More accurate elements and real material properties were used to bring the results closer to reality. The Computational Fluid Dynamics (CFD) method was used to study the effect of water-structure interaction and soil-structure interaction. The results show that the use of the isolation system at the base of the offshore platform has a very significant effect on decreasing the response of the platform to the loads placed on it. Where the isolation system works as a hinge at the pile head and is not allowed to move and rotate for the pile, also the moments are zero. As for the shear force, it is the least that can be compared with the other cases....
Loading....