Advanced Materials Research Vols. 838-841

Abstract: As one of the key steps in the process of durability design and redesign, corrosion monitoring of reinforcement in concrete is of importance. To ensure the concrete durability of the quay structure, corrosion monitoring systems are utilized in Port Said East Container Terminal - Phase 2, Egypt. Embedded half-cell potential reference electrodes and anode ladder systems were used together. Early stage corrosion monitoring data in a precast slab is presented. Comparison of half-cell potential and anode ladder system data give some comprehensive understanding of the mechanism of the corrosion monitoring.

Abstract: The paper shows the results of monitoring activities to check the structural response and the level of damage of two historic monument of LAquila: San Pietro di Coppito and Santa Maria Paganica, that were damaged by the main earthquake of April 2009. The diagnostics operation was planned and carried out in situ and in laboratory to verify the integrity of the residual stiffness of the structures and to define the mechanical parameters of the material. The mechanical characterization of materials was carried out through destructive tests on samples, taken directly on site, and micro-destructive tests through single and double flat jacks. To give a first qualitative assessment of overall was used sonic test (non-destructive test) on the main macro-structure. The global structural health monitoring (SHM) was carried out through ambient vibrations to define the real dynamic behavior in serviceability state and to calculate - via a modal identification of output-only systems-the dynamic parameters (mode of vibration, frequencies, displacements and damping ratios). The aim of this research is to prove the reliability of different diagnostic methodologies, the real extent of global and local damage and the extent of the residual stiffness of the macro elements of the structures (façade, tower, walls of nave, transept) that are subjected to different mechanism of failure.

Abstract: Developing statistics methods to distinguish significant factors associated with roadways is one of the most feasible accesses to understand the nature of traffic accidents. In this study, zero-inflated negative binomial (ZINB) model was developed to allow for overdispersion and excess zeros, as well as the factors of land use, design and environment to examine the effects. The statistical tests show that ZINB model is preferred to zero-inflated Poisson and negative binomial models due to its ability to describe crash counts associated with severe injuries and fatalities more effectively. The results show that fatalities are positively associated with segment length, surface width, land use variables and rainfall. For example, an increase of one inch rainfall will result in an increase of 0.02% in fatalities. Interestingly, distances to hospitals yield positive impact, which suggests that longer distances lead to higher fatalities, presumably due to time lost in transporting crash victims to hospitals.

Abstract: The correlation and Hausdroff dimensions of traffic flow and speed series are analyzed based on the Fractal theory. Using the traffic flow data of four typical expressways in China as input sample, the data statistical results indicates that both synchronized and free flow state are fractal and chaotic. In addition, traffic flow rate and speed time series are determined by different intervals and then G-P arithmetic is applied to estimate their correlation dimensions and the Hausdroff dimension. The results also illustrates that Fractal dimension could by clearly identified, which provides a useful tool for expressway operation management and facilities provision.

Abstract: Dynamic traffic data quality evaluation can provide reliable data support for the traffic management system. This paper aim at three kinds of common failure data, put forward the traffic flow data quality control methods and process. First time evaluate the data quality in three stages, and each stage respectively for all kinds of ITS detector, and builds the six index system. Finally take Beijing as an example to analyze and verify the method of this paper.

Abstract: In recent years, as the traffic congestion has been increasing serious in Beijing, many advanced transportation science and technologies have been proposed to solve the traffic problems. Intelligent control of intersection has been one of the major elements globally in the research on road traffic congestion. Based on the experience of engineering practice, this paper does research of intersection fuzzy control modeling and the fuzzy control optimization modeling based on neural network. Then, it puts forward the method of intersection fuzzy control design based on state automaton technology. Based on Matlab/VAP, it presents the method of intersection fuzzy control simulation modeling. Finally, making an actual intersection for an example, it compares the effect of timing control, induction control, fuzzy control, and neural network fuzzy control.

Abstract: Dense urban group is the inevitable product of relative developed stage of economic and social development. In order to ensure the sustainable development of dense urban group and provide a basis for formulating the transportation infrastructure of scientific development planning, this paper analyzed the traffic demand characteristics in dense urban group. The paper makes use of the statistic analysis method to analyze traffic demand characteristics, especially travel intensity, travel modaltrip time consume and trip distance. It can be concluded that trip number per person and traffic connection of dense urban group are far higher than other regions and the highway is main travel modal. However its average trip distance is low in the nationwide scope.

Abstract: Based on empirical microwave data on the second Ring Road in Beijing, spatial and temporal characteristics of traffic congestion were analyzed. Three specific indexs for the congestion have been analyzed, i.e., congestion duration, time percentage of traffic congestion and key congestion sections. The hazard-based traffic congestion duration model was established through survival method. Temporal-spatial distribution of traffic congestion was studied using non-parametric method. The discrepancies of traffic congestion on different time and different links were considered. Results show that there has a big difference on congestion duration and congestion number between different links. Hazard rate will be less than 10% when congestion lasting more than 20 minutes. Three characteristics of the key congested points are confirmed. The judgment for key congestion sections show that key congestion segments have original affect to other sections.

Abstract: In this paper, considering the influence of mixed traffic and overtaking on traffic flow, the formula of viscous resistance was put forth; a new Hydrodynamics model was established. Discrete analysis was carried out on the mechanical equation through the difference method, through which the change in the traffic flows parameters through time and space can be analyzed. Finally, the measured data simulation analysis results show that the new traffic flow model is of certain practical reference.

Abstract: This paper presents a new lane-changing model of multi-lane mixed traffic flow. The influences of heavy vehicles on lane-changing are analyzed. An improved accumulated speed benefit model is proposed in which drivers generate lane-changing intentions based on accumulated speed benefit of preceding vehicle in target lane over the preceding vehicle in current lane, not just relative to the speed and desired speed of subject vehicle. Drivers may accelerate or decelerate during lane-changing due to different traffic conditions. Simulations show that with the increase in the proportion of heavy vehicles, lane changing frequency first increases and then decreases. The model is validated with empirical data.