Automatic Road Survey by Using Vehicle Mounted Laser for Road Asset Management

In most countries local roads (i.e., urban and rural) form over 80% of the entire road network and constitute the country's largest asset value. In order for local roads to remain fit for purpose and maintain their value, they require periodic maintenance. To make the best use of scarce maintenance resources, road maintenance needs to be preventative which requires the condition of the road to be assessed periodically. Traditional road surveys suffer from the lack of repeatability and reproducibility, are high cost and time consuming. This work proposes a vehicle mounted point laser system for the automated, rapid and inexpensive measurement of a major mode of local road deterioration, namely fretting. Compared to other technologies such as Ground Penetrating Radar (GPR), visual sensors and the Mobile Laser Scanning (MLS) system, the point laser requires less computational power, is less sensitive to the surrounding environment and is of comparatively low cost. A robust approach is proposed which consists of a number of pre-processing algorithms to deal with noise and the effects of the vehicles dynamic motion, and a signal processing algorithm which analyses histograms of the distance from the road surface measured by the laser to account for changes in road texture. Road fretting measured by the proposed system on a variety of roads is compared with fretting determined using a standard visual assessment process. The results indicate that the proposed system can measure road fretting to the levels of detail which are suitable for planning, programming and preparations road management functions

Case Histories of Settlement Performance Comparisons on Ground Improvement Using Soil Stiffness

Ground improvements often aim to reduce settlement risks for foundations and this requires reliable methods of prediction. Current approaches are based on empirical procedures and methods developed over 30 years ago. This has resulted historically in designs and installations of unnecessarily sophisticated foundations. In addition many developments now encountered by ground improvement contractors involve previously developed or ‘brownfield’ sites made up of heterogeneous and variable made ground. Methods to predict settlements traditionally use destructive and invasive approaches such as SPT or CPT that can be insensitive to time dependent changes, which often occur when brownfield sites are improved. By comparison geophysical methods are both non-invasive and non-destructive. One such technique that has demonstrated considerable promise is that of continuous surface wave determinations, which allows stiffness depth profiles to be obtained in a cost effective way. A recently developed method to determine settlements from these data has shown through four case studies presented in this paper to accurately predict settlements measured from zone tests. Thus offers a potentially more reliable way to predict settlement profiles than traditionally used methods

An investigation of the suitability of the construction of an old railway embankment for a new freight route

In Europe there is increasing political, environmental and economic pressure for more freight to be carried by rail. Consequently, initiatives are underway to recommission redundant and under-utilised railway infrastructure. There are a number of technical and environmental issues which must be addressed in order to reuse such lines, including designing a suitable track substructure which can carry the proposed freight at design speeds and loads which far exceed those originally intended. To investigate the feasibility of utilising such infrastructure, research was conducted on a heritage line at East Leake, UK. The research consisted of measuring the performance of the existing track, field and laboratory trials to determine the engineering properties of embankment materials and the development of an analytical methodology to establish a suitable structural design for a conventional ballasted railway track. The preliminary analysis demonstrated that a thickness of 0·44 m of granular material placed on the embankment would be sufficient to prevent structural failure of the embankment for freight trains with a wheel load of 125 kN travelling at up to 125 km h−1 for a period of 60 years. The thickness of granular material is similar to that currently used on similar lines in the UK