Papers by Keyword: Highway

Abstract: The goal of the highway maintenance achievement and effect contract management is to maximize reduce the maintenance cost, prolong the service life of the highway; preventive maintenance investment little, benefit is good, spend less money, and prevent illness.

Abstract: In this paper we propose a stepwise genetic algorithms approach for optimizing highway alignments for improving computational efficiency and quality of solutions. Our previous work in highway alignment optimization has demonstrated that computational burden is a significant issue when working with a geographic information system (GIS) database requiring numerous spatial analyses. For solving real-world problems working directly with real maps through a GIS is highly desirable. Furthermore, saving computation time can enhance adoptability of a model especially when a study area is relatively large, or involves many sensitive properties, or if locating complex structures such as intersections, bridges and tunnels is necessary. It is well acknowledged that in many optimization processes subdividing large problems into smaller pieces can decrease the computation time and produce a better solution. In this research two different population sizes are used to develop a stepwise alignment optimization when employing genetic algorithms in suitably subdivided study areas. An example study shows that the proposed stepwise optimization gives more efficient results than the existing methods and also improves quality of solutions.

Abstract: The purpose of this study was to evaluate flow characteristics on two-lane rural highways and to develop criteria for highway widening The study is conducted on two tracks: theoretical development of delay models and use of a simulation model to estimate the effect of certain parameters on delay and percent-time-spent-following. Models of delay are presented, as are the regions in which the traffic is stable or unstable. It was also possible from the simulation to obtain the percent-time-spent-following, which is a key parameter in determining level-of-service on two-lane highways.The accrued delay over the usable life of a two-lane highway pavement, assumed to be 20 years, was discounted to present monetary value This was then compared to four typical construction costs for different terrain types. The threshold average daily traffic volumes were determined at the points where the present value of the accumulated delay was equal to the cost of constructing two more lanes. These threshold values can be used as criteria for widening a two-lane highway and converting it into a four-lane facility. Additional criteria, based on percent-time-spent-following, are also presented.

Abstract: Many long-span suspension bridges have been built around the world, and many of them carry both of rail and road traffic. Fatigue assessment shall be performed to ensure the safety and functionality of these bridges. This paper first briefly introduces the main procedure of fatigue assessment recommended by British Standard, and then it is applied to the Tsing Ma suspension bridge in Hong Kong. Vehicle spectrum of trains and road vehicles are investigated based on the measurement data of trains and road vehicles recorded by the Structural Health Monitoring System (SHMS) installed on the bridge so that fatigue damage assessment will be more realistic and accurate. Stress influence lines corresponding to railway tracks and highway lanes are established based on a complex finite element bridge model so that an accurate vehicle-induced stress response can be estimated based on them. The fatigue-critical locations for different type of bridge components are identified in terms of the maximum stress range due to a standard train running over the bridge. Finally, the fatigue life at the fatigue-critical locations due to both trains and road vehicles are estimated, and the result indicates the bridge is in very good condition.

Abstract: In the algorithm of Corner Reflector Interferometric Synthetic Aperture Radar (CR-InSAR), the identification of Corner Reflector (CR) points in SAR images is necessary. Due to the uncertainty of traditional method in estimating the row and column information of CR, this paper presents a method for CR points’ identification, which is based on the intensity and correlation coefficient. The method has been successfully used to find the CR points in the six SAR images of the study area where the identification of CR points installed along a high way is difficult. The results show that the method presented is effective and reliable which will play important role in the deformation monitoring in highway using CR-InSAR algorithm.

Abstract: In order to improve the operation safety under disastrous conditions of highway, the classification of highway catastrophic conditions was analyzed. And then the operation safety management and the kinds of countermeasure and foundation of decision-making for emergency disposal against disastrous conditions of freeway were put forward.

Abstract: At present the highway horizontal curve section of Anti-glare panels with a uniform height, through investigation and analysis, the arrangement of the glare effect is not very good ,under mixed traffic, to analyze the reasonableness of the highway glare plate height,the ighway glare plate heigh of the road sightline safety model is set up , the design speed of 60km / h, 80km / h,anti-glare plate height of model is proven。Concluded，In the combinations of different vehicles，anti-glare plate height ranges between 1.15 and 1.65；By contrasting static line of sight and moving-horizon，in thedifferent velocity, when vehicles travel a critical location, vehicle traffic safety start to receive greater impact. Conclusions can be got,first,vehicles travel in the flat curve sections, according to different traffic, adopt different glare height; When the design speed is 60km / h, if central angle is less than 15 °, vehicles which is traveling on the section is safe; When the design speed is 80km / h, if central angle is less than 30°, vehicles which is traveling on the section is safe.

Abstract: Abstract：Polyurethane concrete which applies to the rapid repair highway pavement was systematically researched. Influences on mechanical properties of the polyurethane concrete of cement-dinas and binder-aggregate ratio, curing agent dosage, thinning agent dosage, etc. were analyzed in this paper. Furthermore, the optimal formulation materials were gotten to use in the repairment of used-broken cement blocks in the experiment. Simultaneously, the microstructure of polyurethane concrete and their adhesive situation bewteen waste cement blocks were observed through scanning electron microscope (SEM). The results show that the flexural strength of the specimen for two hours can reach to 6.67 MPa, and the compressive strength can reach to 9.15MPa, which can achieve the rapid pavement repair on highway in two hours, and it is superior to the related Chinese Standard. Besides the SEM images indicate that polyurethane molecular and aggregate are firmly bonded to each other as well as the cementation between polyurethane concrete and concretes, it means that the material has characteristic of rapid repair as well as good mechanical property.

Abstract: s. In this paper, we discuss the design and calculation methods of Circular-shaped Corrugated Steel Culvert Pipe (CCSCP) used in highway construction. With many advantages such as lightweight, environment friendly, cost-effective, rapid construction, etc., Corrugated Steel Culvert Pipe (CSCP) have been widely used in highway construction acting as the alternative of RC culvert in China in recent years. It will not crack under impact loads or vibrations due to the inherent strength of steel and the flexibility of the corrugated pipe section. The high ring compression of the pipe absorbs and transfers the load to the surrounding soil around the entire circumference. In this paper CCSCP is a kind of culvert which is fabricated to a circular shape by several pieces of corrugated steel plates jointed by high strength bolts. In this paper, a serial test is conducted on site in process of the fabricating of the CCSCP used in the construction of Shanghai North Outer Ring Line Highway in China. In addition, 3D FEM analysis is performed with the intent of contrasting with the result of the test. Some design methods are proposed in this paper, and they will be useful guidelines for safe design of CCSCP.

Abstract: Based on the geometry irregularity of pavement, an expression of the traffic load was put forward. The influence law of design parameters of each part of highway and pavement geometry irregularity on vertical deformation of highway was discussed by the three-dimension finite element numerical analysis. The research shows that the vertical deformation range of highway under the action of traffic load is generally semi-circular; the influence of surface stiffness on vertical deformation is different in different horizontal positions of surface; the influence of subgrade stiffness and foundation stiffness on vertical deformation is remarkable, but that of course stiffness is small; the rational matching of all parts of highway can effectively reduce the vertical deformation; with the increase of geometric irregularity index, the vertical deformation increases significantly.