M25 Motorway Research Articles

Contribution of construction activity to aggressive ground conditions causing the thaumasite form of sulfate attack to concrete in pyritic ground

Abstract Historically, the potential for sulfate concentration to be increased as a result of disturbance of pyrite-bearing ground during construction has not been taken into account in UK guidance documents for concrete specification such as BRE Digest 363. This omission was found in 1998 to have contributed to the occurrence sulfate attack in the foundations to several bridges on the M5 motorway founded on pyrite-bearing Lower Lias Clay. The concrete for these was specified to meet the maximum Sulfate Class 2 natural sulfate levels measured during site investigation, however, Sulfate Class 3 and Class 4 levels were generated subsequently by oxidation of pyrite in backfill. In response to the M5 cases, new UK guidance has been issued for assessing pyrite-bearing ground which may be disturbed by construction activity, this being based on the newly defined parameter total potential sulfate.

Evidence from the highways agency thaumasite investigation in Gloucestershire to support or contradict postulated mechanisms of thaumasite formation (TF) and thaumasite sulfate attack (TSA)

In March 1998 the thaumasite form of sulfate attack (TSA) was identified in the reinforced concrete foundations of Tredington Ashchurch Road Bridge on the M5 Motorway in Gloucestershire, UK and the UK Government’s Highways Agency appointed Halcrow to investigate the problem. A total of 28 structures were selected for investigation to encompass sites where bridge works were planned and structures were assessed to be at greatest risk as well as to provide a representative sample of sites and structure types. Desk study work and peer reviews were continued throughout the project to establish protocols for the site work and facilitate the interpretation of the data. The latter included a dual approach of a systematic examination of the data collected to identify trends coupled with a review of postulated mechanisms for the formation of thaumasite from the desk study work against the data from the investigation. This paper summarises the findings of this review, which examines in detail four proposed stages in the development of TSA.

Defamiliarizing the Mundane Roadscape

It is a popular and academic notion that routine driving along motorways signifies contemporary alienation through a kind of serial “non-space.”The author counters these dystopian assumptions about the character of this everyday pursuit by exploring his own experience of driving along England’s M6 motorway, showing how roads are enmeshed within unpredictable, multiple flows of ideas, sensations, other spaces and times, narratives, and socialities. By critiquing notions that autospace is inherently linear and featureless, that driving is asocial and desensitizing, and that the quotidian is a realm of unthinking and automatic behavior, he shows how it is precisely in the realm of mundane space-time that both homely familiarities and imaginative connections can be fostered.

Selection of demolition techniques: a case study of the Warren Farm Bridge

There are numerous demolition techniques available to the demolition contractor from the well‐known blasting techniques to the less known hydrodemolition techniques. It is essential for the demolition contractor to be aware of the various types of demolition techniques available in the demolition industry and to know their advantages and disadvantages. It is also equally important for the demolition contractor to have a set of criteria to follow in order to arrive at the most appropriate demolition technique to employ on projects. This paper outlines the case study of the demolition of Warren Farm Bridge over the M1 motorway in the UK. The demolition was closely followed from the planning stage until the actual execution on‐site with the co‐operation of the demolition contractors and site agents. The paper also discusses the selection criteria for demolition techniques and as a result some guidelines for selecting a demolition technique have been produced.

Excavation of an Iron Age and Romano-British enclosure at Woodend Farm, Johnstonebridge, Annandalw, 1994 and 1997

Excavations were undertaken at a multi-vallate enclosure in advance of the construction of an extension of the M6 motorway. Geophysical survey and excavation revealed a third bank beyond two upstanding banks. Within the interior, seven separate blocks of superimposed buildings were observed, together with an eighth, single-phase structure interpreted as an animal pen. Artefacts were few, consisting of worked stones and querns, while the radiocarbon dates indicated a Romano-British date for much of the occupation, although the enclosure was built in the pre-Roman Iron Age. Includes separately authored reports on:

Motorway speeds in wet weather: the comparative influence of porous and conventional asphalt surfacings

This paper examines motorists’ speeds in wet weather compared with non-hazardous dry conditions (the control) for two separate survey locations on the M4 motorway, south Wales. One site was surfaced with conventional asphalt, whilst the other location had a porous asphalt wearing course. The aim of this study is to establish whether drivers compensate for the additional risks posed in rain by reducing their speed in wet weather. Drivers are slowing down in wet weather, but only marginally; and although the speed reductions proved statistically significant, they are insufficient to compensate for the additional wet weather risks imposed. Such findings have broader implications for the government’s road safety targets.

Zinc, lead, cadmium and copper concentrations of meadow plants along the M3 motorway

The toxic heavy metal concentrations were investigated in plants in a meadow located 51 kilometres from Budapest along the M3 motorway. The field is regularly harvested, and the hay is used as fodder. The area under investigation is situated directly alongside the protecting fence of the motorway. The soil of the area is classified as chernozem brown forest soil. In 2000 approximately 22,860 cars per month travelled on the motorway. The plant samples were taken at a distance of 5, 10, 25, 50 and 100 metres from the motorway. At each distance 10 samples were collected. After digestion with hydrogen peroxide and nitric acid the zinc, lead, cadmium and copper contents of the samples were analysed using an ICP spectrophotometer. After analysing the data it was established that for each of the heavy metals the concentration of metal in the plant samples decreased as the distance from the motorway grew. The measured zinc, cadmium and copper concentrations were similar to those reported by other authors (on average 44.9, 0.276 and 5.25 mg kg-1), while the values of the lead concentration were lower than those published previously (on average 2.93 mg kg-1). This may have been due to the widespread use of lead-free fuel.

Concrete in aggressive ground

BRE publishes guidance on concrete in sulphate-bearing ground and groundwater in the form of BRE digests. A new edition of Special Digest 1 (SD1), first published in 2001 with a revised edition in 2003, was published in 2005 following the completion of a four-year programme of research on the thaumasite form of sulphate attack (TSA). TSA was first identified on high-quality concrete foundations on bridges on the M5 motorway in the UK. Thaumasite results from the reaction of sulfates with the calcium silicate phase of Portland cement. SD1:2005 deals with the specification of concrete for buildings and civil engineering construction in contact with aggressive ground in the UK. The six parts of SD1 have the following titles: introduction, chemical attack on conaete, assessing the aggressive chemical environment, specifying concrete for general cast-in-situ use, specifying surface-carbonated precast concrete for general use in the ground, and design guides for specific precast concrete products. The key changes between the 2003 and 2005 editions are explained. The relationship between SD1:2005 and BS and EN standards is outlined.

SRP Meeting: Visit to Hack Green Secret Nuclear Bunker 20 June 2001

From the first announcement of the visit to Hack Green Secret Nuclear Bunker I was intrigued and determined to go there. I was a little concerned about how I would find it - geography has never been my strong point - but I need not have worried: the brown `secret bunker' signs were plentiful and prominent from leaving the M6 motorway to driving into the car park of the establishment. There was a tremendous buffet, with wine, laid on for us following which our guide explained about the history of Hack Green. This huge underground complex was hidden in the Cheshire countryside for over 50 years, it was only declassified in 1993, and would have been the centre of regional government following a nuclear attack - a chilling thought indeed. Now it is a popular tourist attraction. We then went on the behind-the-scenes tour. Our guide ensured that we really got a flavour of what life was like in the bunker and how it was designed to function if it had ever needed to be used in anger. We saw the BBC studio, telephone exchange, ventilation plant room, decontamination facilities and much more. There were many examples of the protective clothing and monitoring equipment in their museum which many of the older members of the group looked at fondly and started reminiscing about using them in the good old days! We ended the visit with a question and answer session in the café and a vote of thanks to Mr Sibert. our enthusiastic guide. In the time allowed we only had a taste of the place and I for one will be returning for a visit at my leisure.

The Effects of Detector Spacing on Traffic Forecasting Performance Using Neural Networks

An investigation was made as to how short‐term traffic forecasting on motorways and other trunk roads is related to the density of detectors. Forecasting performances with respect to different detector spaces have been investigated with both simulated data and real data. Pruning techniques to the input variables used for neural networks were applied to the simulated data. The real data were collected from the M25 motorway and included flow, speed, and occupancy. With the data used in our study, the forecasting performances decrease with the increase of detector spaces. However, by taking the assumed costs of detector infrastructure into account, it may be concluded from this study that increasing coverage to a spacing of 500 m gives little extra benefit and may actually be counter productive in certain circumstances. It was concluded that, on the basis of current evidence, a detector spacing of between 1 and 1.5 km might be optimal.

Formulas for Time of Travel in Channel with Upstream Inflow

For a drainage design to be based on a consistent theory, the kinematic wave time of travel formula for channel flow ought to be used in conjunction with the kinematic wave overland time of concentration formula. This paper contains the kinematic wave time of travel formulas for channels of seven different cross sections. The channels are subject to a uniform lateral inflow and a constant upstream inflow. By means of a computer model that has been validated with the rainfall runoff data from a hydrologically isolated section of the M6 motorway in the United Kingdom, the times of travel in a channel with a vertical curb section were estimated for rainfall intensities ranging from 20 to 100 mm h−1. A comparison of the time of travel estimates from the computer model, and from the time of travel formula, shows that the differences are less than 5%. The derived time of travel formulas are suitable for use in the design of drainage channels whose properties are within the applicability of the kinematic wave ap...

Use of sequential learning for short-term traffic flow forecasting

Accurate short-term traffic flow forecasting has become a crucial step in the overall goal of better road network management. Previous research [H. Kirby, M. Dougherty, S. Watson, Should we use neural networks or statistical models for short term motorway traffic forecasting, International Journal of Forecasting 13 (1997) 43–50.] has demonstrated that a straightforward application of neural networks can be used to forecast traffic flows along a motorway link. The objective of this paper is to report on the application and performance of an alternative neural computing algorithm which involves ‘sequential or dynamic learning’ of the traffic flow process. Our initial work [H. Chen, S. Clark, M.S. Dougherty, S.M. Grant-Muller, Investigation of network performance prediction, Report on Dynamic Neural Network and Performance Indicator development, Institute for Transport Studies, University of Leeds Technical Note 418, 1998 (unpublished)] was based on simulated data (generated using a Hermite polynomial with random noise) that had a profile similar to that of traffic flows in real data. This indicated the potential suitability of dynamic neural networks with traffic flow data. Using the Kalman filter type network an initial application with M25 motorway flow data suggested that a percentage absolute error (PAE) of approximately 9.5% could be achieved for a network with five hidden units (compared with 11% for the static neural network model). Three different neural networks were trained with all the data (containing an unknown number of incidents) and secondly using data wholly obtained around incidents. Results showed that from the three different models, the ‘simple dynamic model’ with the first five units fixed (and subsequent hidden units distributed amongst these) had the best forecasting performance. Comparisons were also made of the networks’ performance on data obtained around incidents. More detailed analysis of how the performance of the three networks changed through a single day (including an incident) showed that the simple dynamic model again outperformed the other two networks in all time periods. The use of ‘piecewise’ models (i.e. where a different model is selected according to traffic flow conditions) for data obtained around incidents highlighted good performance again by the simple dynamic network. This outperformed the standard Kalman filter neural network for a medium-sized network and is our overall recommendation for any future application.

Measuring atmospheric pollution around junction 16 of the M25 Motorway, London, United Kingdom, using lichenophagous invertebrates

AbstractWe investigate some environmental effects of exhaust emissions from motorway traffic in an area centered on the Junction 16 interchange of the M25 (London Orbital Motorway, UK) with the M40 (London‐to‐Birmingham Motorway, UK). This junction is surrounded by woodland and farmland, with urban development to the west and east. Both motorways carry large volumes of vehicular traffic, so one would expect exhaust‐related air pollution to be higher downwind of the junction than in the surrounding area. Epiphytic algae were collected, analyzed, and used as a pabulum for lichenophagous insect larvae. Analysis showed the concentrations of exhaust‐related heavy metals in algal samples collected downwind were generally higher than those for the surrounding areas. An experiment in which insect larvae were fed these algae identified 13 sites that were significantly affected in two discrete areas: the area with high metals to the east (downwind) of Junction 16, and an area of intensively managed forestry with low metals on the western edge of the survey area. These results suggest this methodology may be a useful screening tool for monitoring air quality and managing the biological effects of atmospheric contaminants. Data from such studies would increase the trophic representation of risk assessments for atmospheric contaminants.

Fluctuation analysis of M25 loop data

By calculating exponents relating to the flow velocity of traffic on the M25 motorway in the United Kingdom, evidence is given for scale-free behaviour in the dynamics of traffic at near-capacity flow. Specifically, it is demonstrated that during periods of high demand the flow is well described by a strongly antipersistent fractional Brownian motion. This approach to traffic flow analysis provides a robust and accurate quantitative characterization of the flow which can be used to inform choices of traffic flow prediction methods. Additionally, the quantities calculated here can be used to assess the performance of individual-based traffic simulation models which are finding increasingly widespread use as a means of understanding the impact of potential modifications to motorway networks.

Radio Ga-Ga

Medicine surrounds us. Like a second atmosphere it's every. where, permeating into everything. Go to work, it's medicine. Come home and read the paper, there's medicine on the front page. Open a magazine, there's illness everywhere. Turn on the television, and a thousand fly on the wall docu-soaps scream out at you. Sleep medicine, breathe medicine, eat medicine. We're a nation truly obsessed, unable to live for the present, and running frantically from the inevitable. So perhaps it's not so surprising that even the most innocuous of things have been caught up in our tangled medical lives. I just never realised until recently how bad the situation had become. Two weeks ago, cruising south on the M6 motorway, surrounded …

Case-control study of hospital admission with asthma in children aged 5–14 years: relation with road traffic in north west London

BACKGROUNDEvidence for an association between road traffic pollution and asthma is inconclusive. We report a case-control study of hospital admissions for asthma and respiratory illness among children aged 5–14 in...

Comparison of the heavy metal content of motorway stormwater following discharge into wet biofiltration and dry detention ponds along the London Orbital (M25) motorway

The Surrey section of the London Orbital M25 motorway uses mainly detention pond facilities for the treatment of stormwater runoff. A majority of these implement the use of dry detention basins. However, in a few locations biofiltration facilities operate through the use of reed bed systems. An assessment of the removal efficiencies for both wet biofiltration and dry pond treatment facilities was undertaken. Motorway-derived contaminants, including V, Cr, Mn, Co, Ni, Cu, Zn, Mo, Cd, Sb and Pb, were measured in unfiltered stormwater collected during the initial stages of a storm event using inductively coupled plasma mass spectrometry (ICP-MS). Results suggest that a higher level of motorway-derived heavy metal contamination exists in stormwater runoff from a road section with a higher average daily traffic density. In addition, a comparison of both sites shows a higher percentage removal efficiency of heavy metals in stormwater from the biofiltration facility.

Speed adjustment of motorway commuter traffic to inclement weather

Drivers theoretically acknowledge the need to reduce their speed in inclement weather, but in practice only alter their speed marginally. This paper examines traffic behaviour in three weather categories: fine, rain and misty conditions. Weekly spot speed surveys undertaken on the M4 Motorway, south Wales are analysed. Each survey recorded the 2-lane carriageway. Manual observations were made also concerning the weather at the time of each survey. For consistency commuter speeds occurring on the same weekday peak hour were recorded for a six month period (8–9 am Tuesday mornings), thus, effectively controlling many other external factors that might influence vehicle speeds. Hourly traffic flow information was obtained from an automatic traffic counter located at the survey site. Analysis of this not only confirms the peak hour, but also the consistency the commuters' daily travel routine. Speeds in inclement weather are compared with those in fine conditions (the control). This study finds a small, but significant reduction in mean speeds in both wet weather and misty conditions, and yet such speed modifications are not sufficient to compensate for the increased hazard posed by inclement weather.

M4 BRYNGLAS TUNNELS AND MALPAS ROAD RELIEF SCHEME.

The opening of the award-winning M4 Brynglas tunnels and A4042 Malpas Road relief scheme in May 1995 provided much-needed relief to the M4 motorway at the constriction caused by the dual two-lane tunnel section at Newport, South Wales. The #95 million project provides a new north-south route to the heart of Newport with links to the M4 and the local road network, taking almost a third of the traffic out of the previously congested Brynglas tunnels. This paper describes the variety of challenges presented in the planning, design and construction of the scheme, including two crossings of the tidal River Usk, crossing the M4 close to the tunnels, and a new grade-separated junction at a busy intersection in the middle of Newport. (A)

The Limpsfield Grange disc

In March 1992 a diminutive decorated disc was submitted for comment to the Department of Medieval and Later Antiquities, British Museum. The owner had found it by using a metal detector in an arable field south of the M25 motorway at Limpsfield Grange in the parish of Limpsfield near Oxted, Surrey (NGR TQ 4053). The disc appeared to be an isolated find and a Coroner's Inquest was not held. The piece was subsequendy sent for auction and acquired by the British Museum acting in cooperation with Guildford Museum. There is no Anglo-Saxon material recorded from the immediate area.