A cost estimate is one of the most important steps in road project management. There are ranges of factors that mostly affect the final project cost. Many approaches were used to estimate project cost, which took into...A cost estimate is one of the most important steps in road project management. There are ranges of factors that mostly affect the final project cost. Many approaches were used to estimate project cost, which took into consideration probable project performance and risks. The aim is to improve the ability of construction managers to predict a parametric cost estimate for road projects using SVM （support vector machine）. The work is based on collecting historical road executed cases. The 12 factors were identified to be the most important factors affecting the cost-estimating model. A total of 70 case studies from historical data were divided randomly into three sets： training set includes 60 cases, cross validation set includes three cases and testing set includes seven cases. The built model was successfully able to predict project cost to the AP （accuracy performance） of 95%.展开更多
Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and anima...Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and animals in natural habitats.In this study,we evaluated the effects of different road construction scenarios on animal species movement by using the methods of ecological landscape connectivity in the typical regions of Yunnan Province,China.The results showed landscape connectivity levels(Probability of Connectivity(PC))decreased after road construction and species with lower dispersal abilities were more affected to the subsequent habitat fragmentation.First level roads affected landscape connectivity most significantly.At a distance of 100 m,the PC index decreased more than 50%.Further analysis suggested that the use of landscape connectivity to assess landscape processes revealed the adverse effects on the species movement more effectively compared with the traditional landscape pattern analysis.In addition,we conducted a graph theory and a least-cost modeling discussion,it is obvious that they are powerful tools to represent and analyze landscape networks with respect to related species movement.Network analysis offers a quantitative and simple but effective tool for ecological process assessment and biological conservation on large scales.展开更多
With the continuous growth of Chinas national economy, the development of Chinas road and bridge construction industry has also gained good development space, and advanced road construction technology has also been de...With the continuous growth of Chinas national economy, the development of Chinas road and bridge construction industry has also gained good development space, and advanced road construction technology has also been developed one after another. On this basis, the paper also focuses on the analysis of the basic pavement rolling compaction technology of municipal road and bridge projects in our country. Firstly, the theoretical application foundation of the basic pavement rolling compaction technology of municipal road and bridge projects in our country is analyzed. Secondly, the specific process of the basic pavement rolling compaction technology in municipal facilities projects is analyzed. Finally, the application focus of the construction method is further discussed, which involves the control of material yard, soil moisture content, structural layer uniformity and roller usage control, in order to strive to improve the overall construction quality of municipal road and bridge construction in our country.展开更多
Drivers experience variations in travel time due to congestion and delays associated with road construction projects on existing transportation facilities. The effect on the travel time of a link decreases as its dist...Drivers experience variations in travel time due to congestion and delays associated with road construction projects on existing transportation facilities. The effect on the travel time of a link decreases as its distance from the road construction project increases. In addition, the effect could extend to the connecting arterial street links within the vicinity of the road construction project. Therefore, the focus of this research is to model the effect of a road construction project on the freeway and connecting arterial street link-level travel times. Data pertaining to a resurfacing construction project, which lasted for six months,was gathered from the traffic incident management systems(TIMS). The travel time data was collected and processed, for each selected freeway and connecting arterial street link,for six months before the start of the resurfacing construction project and six months during the construction of the resurfacing project. Generalized linear models(GLM) were developed and validated for before and during the construction project periods with the average travel time on a link as the dependent variable. Data such as time-of-the-day, dayof-the-week, the distance of a link from the work zone, subject link characteristics, and upstream and downstream link characteristics were collected and used as the predictor variables. The results indicate that the subject link, upstream link and downstream link characteristics have a significant effect on the freeway and connecting arterial street linklevel travel times due to the resurfacing construction project.展开更多
文摘A cost estimate is one of the most important steps in road project management. There are ranges of factors that mostly affect the final project cost. Many approaches were used to estimate project cost, which took into consideration probable project performance and risks. The aim is to improve the ability of construction managers to predict a parametric cost estimate for road projects using SVM （support vector machine）. The work is based on collecting historical road executed cases. The 12 factors were identified to be the most important factors affecting the cost-estimating model. A total of 70 case studies from historical data were divided randomly into three sets： training set includes 60 cases, cross validation set includes three cases and testing set includes seven cases. The built model was successfully able to predict project cost to the AP （accuracy performance） of 95%.
基金Under the auspices of Nonprofit Environment Protection Specific Project of China(No.201209029-4)
文摘Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and animals in natural habitats.In this study,we evaluated the effects of different road construction scenarios on animal species movement by using the methods of ecological landscape connectivity in the typical regions of Yunnan Province,China.The results showed landscape connectivity levels(Probability of Connectivity(PC))decreased after road construction and species with lower dispersal abilities were more affected to the subsequent habitat fragmentation.First level roads affected landscape connectivity most significantly.At a distance of 100 m,the PC index decreased more than 50%.Further analysis suggested that the use of landscape connectivity to assess landscape processes revealed the adverse effects on the species movement more effectively compared with the traditional landscape pattern analysis.In addition,we conducted a graph theory and a least-cost modeling discussion,it is obvious that they are powerful tools to represent and analyze landscape networks with respect to related species movement.Network analysis offers a quantitative and simple but effective tool for ecological process assessment and biological conservation on large scales.
文摘With the continuous growth of Chinas national economy, the development of Chinas road and bridge construction industry has also gained good development space, and advanced road construction technology has also been developed one after another. On this basis, the paper also focuses on the analysis of the basic pavement rolling compaction technology of municipal road and bridge projects in our country. Firstly, the theoretical application foundation of the basic pavement rolling compaction technology of municipal road and bridge projects in our country is analyzed. Secondly, the specific process of the basic pavement rolling compaction technology in municipal facilities projects is analyzed. Finally, the application focus of the construction method is further discussed, which involves the control of material yard, soil moisture content, structural layer uniformity and roller usage control, in order to strive to improve the overall construction quality of municipal road and bridge construction in our country.
基金funded by the United States Department of Transportation-Office of the Assistant Secretary for Research and Technology (USDOT/OST-R) University Transportation Centers Program (Grant #69A3551747127)。
文摘Drivers experience variations in travel time due to congestion and delays associated with road construction projects on existing transportation facilities. The effect on the travel time of a link decreases as its distance from the road construction project increases. In addition, the effect could extend to the connecting arterial street links within the vicinity of the road construction project. Therefore, the focus of this research is to model the effect of a road construction project on the freeway and connecting arterial street link-level travel times. Data pertaining to a resurfacing construction project, which lasted for six months,was gathered from the traffic incident management systems(TIMS). The travel time data was collected and processed, for each selected freeway and connecting arterial street link,for six months before the start of the resurfacing construction project and six months during the construction of the resurfacing project. Generalized linear models(GLM) were developed and validated for before and during the construction project periods with the average travel time on a link as the dependent variable. Data such as time-of-the-day, dayof-the-week, the distance of a link from the work zone, subject link characteristics, and upstream and downstream link characteristics were collected and used as the predictor variables. The results indicate that the subject link, upstream link and downstream link characteristics have a significant effect on the freeway and connecting arterial street linklevel travel times due to the resurfacing construction project.
