Parichatprecha, Rattapoohm
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Parichatprecha, Rattapoohm
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rattapoohm.pa@kmitl.ac.th
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Item type:Publication, Structural Behavior of LC-GFRP Confined Waste Aggregate Concrete Square Columns with Sharp and Round Corners(2022-09-01); ;Rodsin, Kittipoom ;Chaiyasarn, Krisada ;Ali, NazamReusing construction brick waste to fabricate new concrete is an economical and sustainable solution for the ever-increasing quantity of construction waste. However, the substandard mechanical properties of the concrete made using recycled crushed brick aggregates (RBAC) have limited its use mainly to non-structural applications. Several studies have shown that the axial compressive performance of the concrete is a function of the lateral confining pressure. Therefore, this study proposes to use low-cost glass fiber-reinforced polymer (LC-GFRP) wraps to improve the substandard compressive strength and ductility of RBAC. Thirty-two rectilinear RBAC specimens were constructed in this study and tested in two groups. The specimens in Group 1 were tested without the provision of a corner radius, whereas a corner radius of 26 mm was provided in the Group 2 specimens. Specimens in both groups demonstrated improved compressive behavior. However, the premature failure of LC-GFRP wraps near the sharp corners in Group 1 specimens undermined its efficacy. On the contrary, the stress concentrations were neutralized in almost all Group 2 specimens with a 26 mm corner radius, except low-strength specimen with six layers of LC-GFRP. As a result, Group 2 specimens demonstrated a more significant improvement in peak compressive strength and ultimate strain than Group 1 specimens. An analytical investigation was carried out to assess the efficiency of existing compressive stress–strain models to predict the peak compressive stress and ultimate of LC-GFRP-confined RBAC. Existing FRP models were found unreliable in predicting the key parameters in the stress–strain curves of LC-GFRP-confined RBAC. Equations were proposed by using nonlinear regression analysis, and the predicted values of the key parameters were found in good agreement with the corresponding experimental values. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Collapse prevention of pre-stressed electric transmission poles using glass fiber reinforced polymers(2025-07-01); ;Rodsin, Kittipoom; ;Mehmood, TahirNawaz, AdnanNatural hazards such as strong winds, typhoons, and earthquakes have caused massive economic losses in the form of damage to residential and life-line structures. Electric transmission infrastructures are life-line structures susceptible to severe damage under lateral loads like wind and earthquakes. This study focused on vulnerability assessment and measures to reduce the expected damage to the prestressed electric transmission poles under lateral loads. The Glass Fiber Reinforced Polymer (GFRP) sheet is selected as a strengthening material because the fiber cost is affordable but still has acceptable high tensile strength. A full-scale 12-meter-long prestressed transmission pole was tested under reversed cyclic lateral loading. Furthermore, another specimen strengthened with the GFRP sheet was tested to quantify the effectiveness of this technique. The experimental results show significant improvement in the lateral response behavior of prestressed poles in terms of lateral drift capacity, ductility, and energy dissipation characteristics. The GFRP-strengthened specimen exhibited a significantly enhanced lateral drift capacity (more than 100 %) compared to the control specimen. The performance of GFRP in preventing the collapse of a full-scale transmission pole is proved experimentally in this study. Finally, a numerical model based on the fiber modeling concept was also implemented in the open-source platform OpenSees to simulate the observed hysteretic behavior for strengthened and unstrengthened prestressed electric transmission poles. The application of this strengthening method is shown to be very practical for collapse prevention of existing PC poles both in terms of performance and budget. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Detection of Isolated Track Defects Using Axle Box Acceleration from Multibody Simulation and Recurrent Neural Network(2026-01-23) ;Plodphai, Kritat ;Petcharat, Thitiwut; Railway track inspection is typically conducted cyclically, which is slow, budget-intensive, and time-consuming, as it can only be performed during non-service periods when trains are not in operation. Currently, there are emerging concepts and research studies utilizing railway defect detection through acceleration measurements from axle box mounted on service trains, as this approach offers easier implementation, reduced costs, and time efficiency compared to conventional methods. However, the diagnostic process remains challenging due to the high complexity and large volume of data involved. This research presents a method for applying Recurrent Neural Network (RNN) that works with time-series data in diagnosing railway defects by classifying three specific types of isolated defects: squats and corrugation. The training samples for the neural network were derived from axle box acceleration data obtained through multibody simulation analysis that modeled various railway conditions, speeds, and defect characteristics. A total of 360 samples from the multibody model were used for training, validation, and testing. The study results showed that the Recurrent Neural Network (RNN) achieved an average defects classification accuracy of 91.67%. Furthermore, the study findings revealed that the developed RNN model can accurately predict the location and classify defects, with particularly high accuracy in predicting the location and defects caused by long-pitch corrugation. The study concluded that the developed RNN model can efficiently learn and classify defects from axle box acceleration data obtained from multibody simulation. This approach can be applied as a guideline for railway damage diagnosis in future maintenance applications. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Low-Cost Glass Fiber-Reinforced Polymer Composite Wraps for Strengthening Deep Beams with and without Longitudinal Openings(2025-08-01) ;Rodsin, Kittipoom ;Ejaz, Ali ;Hussain, Qudeer; This is a preliminary work on the application of low-cost glass fiber-reinforced polymer composites (Lo-Gs) wraps to enhance the structural response of shear-critical deep beams with and without openings. This study explores the performance of nine deep beams divided into three groups depending on the existence and number of longitudinal openings: solid section beams (Group 1), beams with one opening (Group 2), and beams with two openings (Group 3). Each group consisted of one unstrengthened beam and two beams strengthened with either one or two layers of Lo-Gs wraps. The results showed that Lo-Gs confinement effectively delayed failure in strengthened beams, while having minimal impact on the sudden failure behavior of unstrengthened specimens. Solid section beams exhibited peak load increases of 12.1% and 20.2% with one and two wraps, respectively. In contrast, beams with openings demonstrated higher but more variable strength gains. The presence of longitudinal openings diminished the effectiveness of the wraps in improving ultimate deflection and energy dissipation. While solid beams achieved up to a 130.1% increase in energy dissipation, beams with one and two openings showed lower gains of 63.4% and 57.0%, respectively. Existing design models, calibrated for synthetic FRPs, poorly predicted the behavior of beams with Lo-Gs wraps and neglected the effects of openings, emphasizing the need for further research and model development to address these limitations. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Application of Multibody Dynamics Simulation in Approximation of Rail Vehicle Dynamic Envelope(2023-01-01); ;Petcharat, Thitiwut ;Kim, Ki DuThe master plan for Thailand's Eastern High-Speed Rail Project calls for the Airport Rail Link to be shared with high-speed trains. To ensure the safety of mixed operations, it is imperative to assess loading and structural gauges. This study determined the dynamic envelopes of rail vehicles using multibody dynamics modeling, focusing on three rolling stock models-Siemens Desiro UK Class 360/2 EMU, CRH2C EMU, and Shinkansen Series 300 High-Speed EMU-across a spectrum of operating conditions. Factors such as train mass, suspension characteristics, running speed, wheel wear, track geometry, and track irregularities were incorporated as dynamic simulation parameters. The greatest vehicle movement occurred along the westbound curve path, particularly at the transition between the 996-meter-radius curve to the 180-meter-radius curve. The Shinkansen Series 300 exhibited the greatest lateral and vertical maneuverability. Both the CRH2C EMU and Shinkansen 300 Series trains exceeded the structural envelope limitations of the Airport Rail Link.
