Alignment model for trunk road network maintenance outsourcing

Road maintenance outsourcing is now the foremost strategy by which road authorities procure maintenance works. Despite growing application of road maintenance outsourcing, there are conflicting estimates on the effective­ness of road maintenance outsourcing and shortage of appropriate models to align over optimistic expectations of road authorities from road maintenance outsourcing with substantiated benefits. This paper investigates the efficacy of road maintenance outsourcing. In this paper, the different variants of road maintenance outsourcing and road maintenance works are evaluated with a SWOT analysis and a comprehensive literature review respectively. In addition, a road main­tenance outsourcing alignment model based on a decision tree and Balance Score Card is proposed and illustrated with a Nigerian trunk road network authority as a case study. The result of the SWOT analysis and comprehensive literature review establishes fresh insight into road maintenance outsourcing dynamics. The presented road maintenance outsourc­ing alignment model provides adequate pathways that could assist road authorities identify the most appropriate road maintenance outsourcing variant for road maintenance procurement. In addition it aligns actual benefits and expectations of road maintenance outsourcing and facilitates development of SMART metrics for effective assessment of road main­tenance outsourcing. The proposed model is applicable across other infrastructures. First published online: 01 Sep 201

A possible solution of the grain boundary problem for applications of high-Tc superconductors

It is shown that the critical current density of high-Tc wires can be greatly enhanced by using a threefold approach, which consists of grain alignment, doping, and optimization of the grain architecture. According to model calculations, current densities of 4x10^6 A/cm2 can be achieved for an average grain alignment of 10 degree at 77K. Based on this approach, a road to competitive high-Tc cables is proposed.Comment: 3 pages, 5 figure

Sustainable road alignment planning in the built environment based on the MCDM-GIS method

Sustainable road planning in the cities' built-up areas strives to meet traffic demands of society within limited spaces available for construction and various constraints in the built environment considering engineering, traffic, economic, social, and environmental factors. Unlike rural areas, road planning in the built environment can be significantly influenced by the surroundings, such as existing buildings, road network, and land use, and should consider noise and air pollution impact on residents. In addition, road width and road widening are significant factors for road alignment planning. Based on the MCDM-GIS method, the least-cost wide path algorithm is employed for sustainable road alignment planning in the built environment, considering building demolition and land use, traffic congestion, noise impact, air pollution impact, and construction costs. Road width, new road construction, and existing road widening are considered simultaneously. Several methods are proposed to digitalise and parse various sustainable factors into understandable expressions for road alignment planning. Forbidden areas and road buffer areas for road widening are defined. The proposed method is implemented in road planning in Dartford, Kent County, UK. Sustainable factors with different weights can generate various road alignments from different perspectives, and road widths can significantly and locally influence road alignments

Incorporating Soil Surface Erosion Prediction into Forest Road Alignment Optimization

A previous study introduced a forest road design model developed to simultaneously optimize horizontal and vertical alignments of forest roads using a Tabu Search optimization technique and a high-resolution Digital Elevation Model (DEM). In this study, surface erosion prediction was incorporated into the road design model, so that users can optimize horizontal and vertical alignments of forest roads while constrained by maximum allowable sediment delivery from roads to streams. The road alignment optimization model was applied to a part of the Capitol State Forest in western Washington state. The application confirms the potential of the model to determine forest road alignments in a way to reduce total road costs as well as sediment delivery to streams. This paper also discusses the effects of DEM resolution on forest road alignment optimization. The accuracy of generating ground profile and forest road alignments depends on the resolution and accuracy of the DEM. The study results suggest that a 10-m grid DEM might be inappropriate to use for the purpose of road design and alignment optimization due to the lower accuracy in its elevation representation

Reconstruction of Road Embankment Failure Using Reinforced Geogrid: Revisiting the Site After 15 Years

A case history of repair works of road embankment failure at KM39, Route 68, Kuala Lumpur – Bentong Road in the state of Selangor, Malaysia and an observation on the condition of the site after 15 years and some tensile strength testing carried out on buried and exposed geogrid was presented in this paper. Due to heavy rainfall in 1995, about half of the road embankment which was located at the alluvial fan of an upslope stream valley was washout. For the reconstruction of the alignment, the existing half of the alignment was converted into a buffer zone with a row of gabion as a barrier to trap any fallen debris from the upslope stream valley. A geogrid reinforced embankment was constructed to provide an additional area for the new alignment of the road

Road Alignment and Gradient Issues in the Maintenance of Logging Roads in Tanzania

In forestry, roads are essential structures as they provide access to the forest from the establishment phase to harvesting stage. Thus it is important that roads are properly planned, constructed and maintained in order to ensure easy access, smooth transport of forest products, safety, comfort and economy on vehicle operations. For Tanzania where commercial timber harvesting in plantation forests has just started, appropriate values of parameters for road alignment and gradient, in the context of the country's settings, need to be established. This study, which was carried out on a gravel secondary access road, established that traffic and water contribute significantly to road deterioration or loss of road surface materials. Road alignment and road gradient were found to influence the rate of soil loss. The study found that the optimal road grade and curve radii which minimized road maintenance cost in this area were grades less than 6% and radii above 100m respectively. Statistical analysis however showed that there was no significant difference between straight sections of the road and the curve sections in terms of loss of surface layer materials