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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Physical properties of sandy soil stabilized with asphalt emulsion for a highway project

Bellin, Peter A. F., January 1966 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
62

Preliminary investigation of energy dissipation at culvert outlets using a riprap step

Weikle, Belinda M., January 2000 (has links)
Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains ix, 168 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 148-167).
63

Characterization of road materials and environmental conditions for the analysis and design of flexible pavements in Hong Kong

Teague, Frederick Thomas. January 1999 (has links)
Thesis (Ph.D.)--University of Hong Kong, 2000. / Includes bibliographical references. Also available in print.
64

On factors which decide the quality of asphalt concrete surfacings, based upon experience gained in Finland.

Hyyppä, J. M. I. January 1966 (has links)
Thesis--Helsingin Teknillinen Oppilaitos. / Includes bibliographical references.
65

Performance benchmarking of large highway projects

Shrestha, Pramen Prasad, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
66

An expert system applied to earthmoving operations and equipment selection

Alkass, Sabah Toma January 1988 (has links)
The thesis represents an effort to assess the current and future development of expert systems relating to civil engineering problems. It describes the development and evaluation of an Expert System (ESEMPS) that is capable of advising on earth allocation and plant selection for road construction similar to that of an expert in the domain.
67

Approche probabiliste de la sécurité des véhicules légers en zones accidentogènes / Probabilistic approach to light vehicle safety in accident prone areas

Rey, Guillaume 08 December 2010 (has links)
Les sorties de route en virage constituent une part importante des accidents de la route en France, causes d'environ 30 % des accidents mortels pour 2008. Ces accidents se produisent principalement sur route secondaire ce qui montre le besoin du conducteur d'être assisté dans sa tâche de lecture et de négociation du virage. L'objectif de ce travail est le développement d'une méthodologie d'évaluation du risque encouru par le conducteur lors du franchissement d'un virage afin de mettre en place sur les itinéraires routiers un système d'alerte déclenchée en cas de situation potentiellement dangereuse. La méthodologie menant à l'évaluation du risque est basée sur l'emploi des méthodes probabilistes, permettant de prendre en compte fidèlement les incertitudes inhérentes au conducteur, au véhicule et à l'infrastructure. A l'entrée du virage, un dispositif de mesure renseigne sur la position latérale et la vitesse du véhicule arrivant. Une famille de trajectoires de passage en virage est alors stimulée à partir d'un modèle dynamique de véhicule dont certains paramètres d'entrée dépendent des trajectoires mesurées sur le trafic réel. Des indices de risque associés à des critères de sécurité sont ensuite évalués par des méthodes fiabilistes. Les résultats obtenus sont la détermination et la hiérarchisation des paramètres influents sur les critères de sécurité, ainsi que l'évolution des indices de risque en fonction des conditions initiales en entrée de virage. Les applications réalisées dans le dernier chapitre démontrent le potentiel de la méthodologie fiabiliste proposée et son intérêt dans le domaine de la sécurité routière. / Roadway departure while cornering constitutes a major part of car accidents in France, accounting for nearly 30 % of casualties in 2008. Most of them occur on secondary roads and reveal that drivers need assistance for a safe curve negociation. The subject of this work is the development of a methodology to access the roadway departure risk in order to implement in the road infrastructure warning devices alarming the driver in case of potentially dangerous situations. The application of probabilistic methods for the risk assessment allows an accurate representation of the uncertainties arising from the driver, the vehicle and the road infrastructures. At the entrance of the curve, speed and position of the approaching vehicle are measured. Then, a family of trajectories is simulated from a dynamic model. Some of the model input depend on experimental trajectories measured on the real traffic. Finally, savety criteria are chosen and associated risk indices are calculated using reliability methods.The influence of various parameters of the model are studied, and the obtained results are the evolutions of the risk indices as a function of the measured initial conditions. The probabilistic methodology elaborated in the road safety domain constitute a valuable decision support tool for the alarm triggering.
68

Controllability of road vehicles at the limits of tyre adhesion

Kohn, Heinz Joachim January 1998 (has links)
The research project 'Controllability of Road Vehicles at the Limits of Tyre Adhesion' (CROVLA) was established to investigate how tyre and chassis properties contribute to the handling characteristics and stability of vehicles operating at or near to the limit condition. The project involved the Department of Transport, SP Tyres UK Limited, Jaguar Cars and Cranfield University. An extensive proving ground test program of typical limit handling tests provided characteristic driver input and vehicle response data for a variety of vehicle configurations. The test data analysis was based on the concept of correlation. Cross- correlation coefficients and average response time delays were obtained for various pairs of quantities, namely steering angle and torque for the input and yaw rate and lateral acceleration for the response. The predictability of the vehicle response was evaluated by the rate by which the correlation coefficients change with severity. Analogous to the proving ground work, vehicle dynamics simulations were carried out. Two programs were employed to study the steady state performance and the transient limit handling behaviour. The 'Steady State Cornering Model' was used to confirm some basic suspension design rules established for optimising the lateral adhesion of a suspension design. The importance of controlling camber and vehicle jacking by an appropriate suspension design was identified. A detailed vehicle model was built-up using the simulation code AUTOSIM. After validating the model against proving ground data, some parametric studies were conducted to quantify the effects of suspension and tyre properties on the transient limit response behaviour. Proving ground and simulation results suggest that response time lags and cross- correlation coefficients in combination with other handling parameters can be used as objective quality measures. The results quantified to what extent tyre and chassis modifications change the limit handling behaviour.
69

The behaviour of brickwork arches subjected to cyclic loading

Alnuaimi, Matar M. January 2002 (has links)
There are over 40,000 road bridges in the UK and most of them are over a hundred years old. These bridges were not designed to carry today's modern traffic and the everincreasing live loads especially with the introduction of 40 tonne lorries since January 1999. Moreover, in the case of multi-ring brickwork arches the penetration of rainwater and/or overloading with the passage of time breaks the adhesion between the rings leading to ring separation. The loss of continuum behaviour is accompanied by a significant drop in load carrying capacity. It is important that they continue to perform their functions. Sympathetic strengthening is preferred to demolition and replacement. A large amount of work has, in recent years, been devoted to the study of the behaviour of brickwork arch bridges subjected to monotonic loading. However, little is known about the behaviour under cyclic loading. The thesis reports the results of tests under cyclic loading applied at the quarter spans on six large-scale brickwork arch bridges of spans 3m and 5m. Some of them were constructed with damp sand between the brickwork rings, which simulate the defect of ring separation in real bridges. The tests were used to develop a better understanding about the behaviour and failure mechanisms of these arches subjected to cyclic loading. Additionally, the efficacy of surface strengthening to the structural performance of multi-ring brickwork arches was investigated. Both the ring separation and surface strengthening affects the behaviour of arches subjected to cyclic loading where the former reduces the carrying capacity and the latter increases the carrying capacity. The static failure loads of brickwork arches were predicted using four different methods: the mechanism method, Gilbert's 'RING' program, the elastic method and the FE method using ABAQUS software. It was found that the mechanism method and the 'RING' program were conservative in predicting the carrying capacity of the tested arches.
70

A general theory for channel brush design for street sweeping

Peel, Gareth January 2002 (has links)
The objective of this thesis is to develop an understanding of the brushing process for a road sweeper so that a theoretical model of the process can be developed. The brush model has been confined to the kerb operating channel brush that usually sweeps about 80% of the debris on the road in the region of the kerb. The other 20% is swept by a roller brush beneath the vehicle. This has not been included in the study. A concept for a semi-autonomous road sweeping vehicle has also been proposed in order to sweep debris efficiently with minimum fatigue for the vehicle driver, although the debris sensing and control system have not been developed in this thesis. The metal tines of road sweeping brushes are usually rectangular in section (unlike cleaning brushes which are circular in section), giving rise to two commercial brush types. These are the flicking brush (major axis in the radial direction) and cutting brush (major axis in the tangential direction). A theoretical steady-state model of these two brushes has been developed which allows the calculation of brush axial loads, torques and tine deflection geometry as the brush rotates. The theoretical model has been validated experimentally within acceptable limits although this does require an experimental choice of the co-efficient of friction between the tines and the ground, usually between 0.6 and 0.7 for commercial brushes sweeping on concrete and tarmacadam surfaces. A dominant feature of the brush characteristics is the tine wear, as the brush stiffness increases over 120% as the tine shortens by 40%, which is the recommended minimum length taking into account brushing efficiency and damage to the road surface. The model can also be used as a tool to design new brushes so that, for example, by rotating the tine by 30 to 40° from the cutting brush configuration a 20% improvement in mechanical efficiency is predicted. In order to assess the mechanism of debris removal from the road and its subsequent collection by the vacuum unit, the brush model has been incorporated into a brush sweep-gear linkage used by commercial vehicles to track the edge of the kerb. It has been shown that a constant brush contact arc on the road can be maintained by adjusting the brush angle of attack and brush height and that this relationship is independent of the vehicle speed and brush linkage with respect to the kerb. Under these contact conditions efficient sweeping may be expected. In the case of the Johnston 600 sweeping vehicle the brush contact arc angle is 150°. This parameter is used as the output criterion for automatic control schemes that have been proposed to improve brushing efficiency and reduce driver fatigue. These will require the development of an on-line brush height sensor that can also measure brush wear.

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