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Chen S.S.,East China Jiaotong University | Wang D.S.,Jiangxi Ganyue Expressway Co.
Advanced Materials Research | Year: 2013

Taking the bending stiffness, cable static sag and cable inclined angle into consideration, equations of space free vibration of the cable-damper system are derived in this paper. Joining the variable separation strategy and center difference method, the partial differential equations are discretized in space and a set of complex eigenvalue equations, which are solved by state space method, are derived, and both the maximum modal damping ration and the optimal damper parameter are obtained. Several typical stay cables are investigated for both the in-plane and out-of-plane modes under different cable parameters and damper parameters. The results demonstrate that modal damping ratio for the first in-plane mode is significantly affected by the cable static sag only, but those for the other modes affected by cable sag are slight, and cable static sag do not affect the optimal damper parameter for all modes, however the bending stiffness will changes both the maximum modal damping ratios and the optimal damper parameters. Some valuable suggestions are proposed for the optimal damper design. © (2013) Trans Tech Publications, Switzerland. Source

Kuang A.-W.,Changsha University of Science and Technology | Tang Z.-Q.,Changsha University of Science and Technology | Tang Z.-Q.,Jiangxi Ganyue Expressway Co. | Huang Z.-X.,Changsha University of Science and Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2014

To investigate the impact of the link capacity degradation degree on the equilibrium market penetration of advanced traveler information systems (ATIS), the travelers were divided into two classes: "travelers equipped with ATIS" and "travelers unequipped with ATIS". Assuming that two classes of travelers made their route choices based on travel time budget at a given reliability, the equilibrium market penetration model was established by the average travel time budget saving derived from ATIS service between an origin-destination pair, which could be determined by the uncertain road network mixed stochastic user equilibrium modeling approach. A heuristic solution algorithm for solving the model was proposed and some numerical studies on a test network were conducted to analyze the impacts of the information quality, the capacity degradation degree and the level of traffic demand on the market penetration. Results show that the concentration phenomenon is more likely to occur in an uncertain road network. In addition, the improvement of information quality may not be able to increase the market penetration, which depends on the congestion degree of the entire road network more significantly. Source

Yu L.,South China University of Technology | Sun B.,Jiangxi Ganyue Expressway Co.
Proceedings of 2012 IEEE International Conference on Service Operations and Logistics, and Informatics, SOLI 2012 | Year: 2012

Four types of typical discrete Choice Models: Multinomial logit (MNL) model, Nested logit (NL)model, Heteroscedastic Extreme Value (HEV)Model and Mixed logit model, have been proposed and implemented in empirical investigations, although there is no universally acknowledged using principle. Here we report study to test this type of models in a travel mode choice case. we implemented four models calibration using software programmed by ourselves. We found that if sample data satisfied with IIA property, our experience has confirmed that MNL is the first choice in mode split forecasting. The nested logit model and Heteroscedastic Extreme Value (HEV)Model are not significantly better than the multinomial logit model. Mixed logit model corrects IIA flaw, but is somewhat more difficult to estimate. © 2012 IEEE. Source

Zhang J.,Changsha University of Science and Technology | Dai L.,Changsha University of Science and Technology | Zheng J.,Changsha University of Science and Technology | Wu H.,Jiangxi Ganyue Expressway Co.
Journal of Testing and Evaluation | Year: 2016

To investigate the reflective crack-propagation behavior and provide control techniques for asphalt pavements widening, the finite-element models were built to simulate the widened asphalt pavement with a latent joint. The developed finite-element model considered the influence factors, including the loading modes (i.e., the symmetrical and unsymmetrical loading modes), the thickness and modulus of the asphalt concrete surface, the modulus of the new and existing stabilized bases, and the sheet stiffness of the reinforced geosynthetic. The finite-element simulation results show that increasing the thickness or reducing the modulus of the asphalt concrete surface effectively delays the propagation speed of the reflective cracks. The cracking potential reaches the minimum when the new and existing bases have a uniform modulus. Additionally, geosynthetic reinforcement across the joints significantly reduces the stress concentration around the crack tip and slows down the propagation of the reflective cracks. These benefits become greater when increasing the sheet stiffness of the geosynthetic. Finally, an experimental study was conducted to investigate the influence of the types of the asphalt overlay and the geosynthetic reinforcement on the reflective crack-propagation behavior. The experimental results indicate that the geosynthetic-reinforced structure with a lower modulus of the asphalt concrete surface significantly increases the fatigue life of widened pavements, and the polypropylene geotextile performs better than the glass-fiber grid in terms of the extension of the fatigue life. © 2016 ASTM Int'l (all rights reserved). Source

Zhang J.,Changsha University of Science and Technology | Chen Y.,Changsha University of Science and Technology | Wu H.,Jiangxi Ganyue Expressway Co.
International Journal of Earth Sciences and Engineering | Year: 2015

Red clays are widespread in South China. As typical unsaturated soils, they are sensitive to moisture and their mechanical performances deteriorate with moisture changing.. In order to reveal the moisture migration mechanism of the unsaturated red clays by measuring the water content in red clay cylinders at different migration time and then rationally use the local red clays as a filling material for highway embankments, a nondestructive and continuous method to measure the water content can avoid the sample to sample variation and improve the efficiency of moisture migration tests greatly. Accordingly, the red clay cylinders with three degrees of compaction of 90%, 93% and 96% and with five water contents at each degree of compaction were scanned using an X-ray computed tomography (CT). A total of 3 layers were scanned for each specimen and the average CT-value of each red clay cylinder was measured. Then, a relationship between CT-value, dry density and water content of red clay cylinders was developed. Subsequently, the tests were conducted to validate this relationship. The results show that the calculated water contents using the relationship built in this study agree favorably with the measured values, suggesting that the relationship between CT-value, dry density and water content is very accurate to measure the water content of the red clay cylinders. © 2015 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved. Source

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