Duyệt theo Tác giả "Nguyen Tien Thuy"
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Tài liệu Assessing bridge stiffness decline using power spectral density: A case study on Saigon Bridge(2023-01) Nguyen Quang Thanh; Vu Ba Tu; Nguyen Anh Tuan; Nguyen Tien ThuyBridges, especially civil infrastructure, serve a vital role in social activities. A damaged bridge can cause severe consequences such as traffic congestion, economic impacts, and loss of lives. Therefore, it is crucial for infrastructure management communities to detect and assess the condition of damaged bridges to ensure safety. To address this issue, in this study, the authors have put forth a novel set of parameters that can be used to evaluate the reduction in stiffness of spans over time. The stiffness is a critical factor that determines its structural integrity, and it is essential to monitor any changes in this parameter over the lifespan of the bridge. The proposed parameters take into account factors such as the age of the bridge, the material used in its construction, and environmental factors that may contribute to the degradation of the structure. They conducted experiments on a beam structure to evaluate its ability to monitor the reduction in bearing capacity of Saigon Bridge's spans using these parameters. To analyze the vibration signals from a randomized traffic load model, they utilized the power spectral density. The results of the study suggest a correlation between the frequency of harmonics and the high-frequency regions observed in the power spectral density and the decline in the stiffness of spans.Tài liệu Assessing mechanical responses for damage detection in bridge spans through resonance region analysis(2023-03) Nguyen Quang Thanh; Vu Ba Tu; Nguyen Anh Tuan; Nguyen Tien ThuyThis article introduces a new method for evaluating the mechanical behavior of structures to detect potential damages in bridge spans. The study enables us to monitor the stiffness degradation of bridge spans over time, operating under different working conditions. The proposed approach suggests monitoring the operational status of bridge spans at different measuring points, corresponding to different levels of applied load, measurement time, and environmental conditions according to the random theory. The study results demonstrate that changes in the area under the resonance regions of the power spectrum density can provide accurate information on the change in the structural behavior during operational periods. Furthermore, the research indicates that changes in the area under resonance regions can identify hazardous points on different spans of a bridge through different measuring points. Overall, in the future, this method can assist in identifying potential damages and warning of potential hazards to improve safety and reliability for people and vehicles crossing the bridge.Tài liệu Assessment of noise pullution and its impact to the citizens in Ho Chi Minh City(2022-05) Nguyen Tuan Anh; Nguyen Tien Thuy; Pham Thi AnhNoise pollution can cause health and well-being problems for people including hearing loss, stress, high blood pressure, sleep disturbances, etc. Ho Chi Minh City is the primary economic center of Vietnam. Its rapidly development, especially in recent year bring along serious noise pollution. This study assesses the current noise pollution in Ho Chi Minh City and its impact to residential areas by measuring the noise levels due the traffic; industrial and commercial activities in the urban areas. The results show that the noise pollution in Ho Chi Minh city is at alarming level. Several technical solutions has been recommended to reduce the noise level that ultimately improve life quality and further sustainable development in Ho Chi Minh City.Tài liệu Local buckling resistance of Pultruded FRP columns: Theoretical predictions vs. Experimental study(2023-01) Nguyen Tien ThuyFiber-Reinforced Polymer (FRP) in the form of thin-walled plate structures are widely used in different engineering applications due to their outstanding features such as: high strength-to-weight ratio, excellent fatigue and corrosion resistance, etc. Due to the low stiffness, design of FRP material is usually governed by deformations or instabilities, rather than strengths. The development of a technical specification for design of FRP composite structures requires the understanding on buckling behaviour of FRP components. Local buckling of pultruded FRP column is a type of structural instabilities, occurs when the compressive stress reaches to the level that form waves in the flanges or web plates, causing the plastic deformation in the fiber which ultimately reduces its strength and stiffness. This study focuses on the local buckling resistance of pultruded FRP columns by experimental work. The test data were compared to current theoretical and numerical predictions. It is found that the difference of <15% between experiment and predictions can be acceptable. The author recommends that the Kollar’s equations to be used when predicting local buckling of Pultruded FRP column of I or channel shapes.Tài liệu Process of inspecting road bridges in Ho Chi Minh City - Part 1: Existing inadequacies in the current process(2022-05) Nguyen Quang Thanh; Vu Ba Tu; Nguyen Hoai Bac; Nguyen Dang Quang; Nguyen Anh Tuan; Nguyen Tien ThuyQuality inspection of traffic works, including quality control of simple bridge construction, is always a big problem in the management process of current authorities. This article will evaluate the outstanding issues in this current demand test standard, in which the study will build an overview evaluation model of the demand test standard and identify the outstanding shortcomings. The analysis from the article shows that the inspection process has problems that need to be supplemented and improved to both meet the requirements according to the process and properly represent the scientific nature of the problem. In addition, the inspection standards need to strongly eliminate problems that are not really necessary or that do not affect the quality of the work at the time of the survey. The issues investigated from the testing standards in the following sections include: remaining shortcomings in the existing bridge testing process; necessary additions in the bridge inspection process based on the development of science and technology; the bridge health monitoring system has been bringing about important decisions in assessing the quality of the bridge construction; the existing demand testing process – how to better match the rate of change of the present.