Advanced Materials Research Vols. 779-780

Abstract: The pre-stressed composite box-girder with corrugated steel webs is a new kind structure, which includes corrugated steel webs, external pre-stressed cables and shear connectors that connect the corrugated steel webs and the concrete flange slab. In recent years more and more attention has been given to this kind structure and important achievement has been got in bridge engineering in China. In this paper three pre-stressed composite box-girder bridges with corrugated steel webs in China are introduced. Design experiences about the bridges are summarized, and their construction are discussed.

Abstract: In order to realize the curve-type assistance characteristic of the electric power steering system , the parabola-type assistance characteristic is brought out, and realizing it by designing the electric power steering system which is controlled by computer. And then math model of computer control system is constructed, and adopting Z-transform to analysis the stabilization of the system. The result shows that computer control system can realize the curve-type assistance characteristic.

Abstract: Considering the randomness of the traffic flow, a self-adaptive control method for isolated intersection signal timing is proposed, which imitates the traffic polices signal controlling behaviors. Firstly, we define the concepts of Busy Level (for the phase that has got the right of way) and Urgent Level (for the other phases that have not got the right of way). Based on the definitions, the signal control method is put forward, which can be summarized in brief that when Urgent Level is greater than Busy Level, the phase with the highest Urgent Level gains the right of way. Then, based on the fuzzy control theory, we elaborate the fuzzy modeling process of Busy Level and Urgent Level and put forward an optimization method of the membership function using the traversing method. The proposed method is a breakthrough comparing with the old methods that optimize the circle time, the split or the amount of the green time extension. The method has the charactaristics of no fixed circle time, no fixed phase sequence and is more effective to suit the fluctuant traffic flow. At last, the computational results of an simulation demostrates that the proposed method is far more effective than the pretimed signal timing methods.

Abstract: According to the vehicle dynamics theory, the dynamics simulation models of single-vehicle NX_70H flat marked loading capacity of 70t with K5 bogies and NX₇₀ flat marked loading capacity of 70t with K6 bogies under certain loading and running conditions were established by SIMPACK, in order to discuss the change rules of the roll angles, the yaw angles, the lateral offsets and the maximum lateral vibration offsets. Based on the statistical analysis of data calculated by SIMPACK, the results of dynamics single-vehicle models of the two wagon types running on Chinese I and III grade railway lines respectively were compared. Simulation results show that the running speed, the line condition and the height distancing the rail surface all have a significant impact on the maximum lateral vibration offset.

Abstract: Tunnel project across Yangtze River about Line NO. 8 of track traffic located at 450m in upper the second bridge of Wuhan reach. Change of velocity, hydrodynamic axis, diversion ratio of inlet about river reach of project under the different conditions of hydrology were studied through experiment of river engineering model, and the minimal buried depth of the top of tunnel about deep trough is about 7.5 m while the maximal scour depth of section about site of tunnel based on variation of deposition or erosion of riverbed, the possible lowest altitude of eroding, change of swing range of thalweg about river reach of tunnel project, and building of tunnel has no effect on river regime, flood control and shipping for river reach of project. The results can be applicable as a reference for design of project.Key words: tunnel across river; river engineering model; river regime; flood control; altitude of deepest location

Abstract: A two year study of evaluate the valid service life of durable pavement markings on urban roads was conducted in Beijing as a pilot field study of Chinese national transportation product evaluation program and minimum retro-reflectivity requirements standards and road maintenance standards. 34 pavement marking lines including edge line, arrow, skip line, crossing line and stop line were installed on expressway and intersection. Marking materials included thermoplastic with glass beads, preformed thermoplastic tape with glass beads and preformed rubber based pavement tape. Service life evaluation was base on minimum value of durability and retro-reflectivity. Retro-reflectivity attenuation varies at different locations (express way, intersection), different marking functions (e.g., skip line, edge line) and different materials (thermoplastic or tape). It was found the more accumulated traffic, the more loss of retro-reflectivity. The most loss of retro-reflectivity happens at stop lines, skip line and cross line are better, arrows are less, edge line is the best. Cleanliness factor are also considered, retro-reflectivity significantly rises after cleaned. A maintenance schedule for different markings was given in this paper. Stop line, skip line and crossing line are suggested to be replaced every 12 months; arrow and edge line are suggested to be replaced every 24 months with a special concern of cleanliness at urban area.

Abstract: Improper design of grasslands highway curve is an important cause of accident, which research on is not mature. Drivers are the main body of grasslands highway traffic man-machine environment system. The paper aims at four sections of highway curve, using frequency domain analysis and grey correlation analysis method to study the relationship between driver’s HFnorm, LH/HF and the highway curves. Results indicate that it can not distinguish the effects of driver's sympathetic nerve, vagus nerve and the balance between them caused by different curves in statistical terms. In the monotonous landscape grasslands, increasing some curves of different radii appropriately in highway alignment design can relieve driver’s fatigue to a certain extent. Diversification of grasslands highway curve has a less influence on parasympathetic nerve of young drivers with long driving experience than that of old drivers with long driving experience. To ensure the driver’s autonomic nerve activity being at a reasonable state, it is more perfect to design grasslands highway horizontal and vertical curves combined with driver’s LF/HF indexes, and profile grade with driver’s HFnorm and LH/HF indexes. The results can offer part of theoretical support for thorough study on humanity of grasslands highway alignment.

Abstract: This paper analyzed the structure of the intake about 65-gasoline engine, which take into account t of the shortcomings of the lack of intake, a new intake system was re-designed. And a numerical calculation was carried on about the air transport computation on the new system. The result indicated that the intake flow resistance to reduce greatly after the improvement, and the filling ratio has the distinct improvement. And a comparative test has carried. Also the experimental result indicated, the engines useful torsion increased and the fuel oil consumption rate reduces also after the optimization.

Abstract: In order to save energy and protect environment, above all ,to adapt to the requirement of the future city traffic, a new motorized wheel system for mini electric vehicle including in-wheel motor, brake and suspension was proposed .The structure schemes of in-wheel motor, suspension and brake were selected, then the project of directly driven electric wheel system was formed. Some essential performance indexes of electric vehicle considering the traffic condition and environment of city road were studied. According to these performance requirements of electric vehicle, the power and rotational speed of in-wheel motor were reasonably determined. Finally, a multifunctional, high efficient and integrated electric wheel system was established. Results can be used as reference for the research and development of the motorized wheel.

Abstract: A prediction method for the sound radiated power from submerged double cylindrical shells based on measuring vibration of inner shell is presented. The prediction model of submerged double cylindrical shells is established by using modal superposition method. Applied the ratio of the measuring value and theoretical value of the acceleration in one point or mean square velocity of inner shell, and combined with the theoretical value of the sound radiated power, the predicted value of the sound radiated power is derived. The corresponding experiment is carried out in lake. And then the measuring power curve is compared with the predicted power curve based on this method. The result shows that they have good agreement and the average prediction error is less than 2dB.