No abstract available. / Thesis (Ph.D.)-University of Natal, Durban, 1983.

Thesis: M.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1975 / Bibliography: leaf 95. / M.S. / M.S. Massachusetts Institute of Technology, Department of Civil Engineering

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / Includes bibliographical references. / M.S.

The purpose of this research was to develop a simplified analytical procedure for determining the optimal timing for upgrading low-volume roads in developing countries. Most roadway upgradings from gravel to surface treated and to asphaltic concrete are carried out when total transport cost on a road becomes high as a result of high traffic and the consequent rapid deterioration of the roadway. Adequate timing of upgrading strategies ensures effective use of resources and lower total transport cost. This study examined existing systems, models, and approaches for estimating total transport cost components. An analytical procedure was then developed using a decision-tree concept to delineate all possible upgrading strategies within a plan period. The decision-tree concept depicts all the possible upgrading strategies within a plan period with decisions on roadway upgrading made at certain decision intervals. The total transport cost of the upgrading strategies is evaluated to establish the optimal strategies and traffic warrants for improving a roadway surface. A computer program PVMNT was written to facilitate the computation of the total transport cost. A case study was presented to demonstrate the application of the analytical procedure. The case study revealed interesting results on the changes of optimal upgrading strategies with changes in base traffic volume and growth rate. However, general conclusions could not be drawn based on the results of the case study. These results, as well as the analytical procedure, should be of interest to engineers responsible for providing low-volume roads in developing countries.

No description available.

The primary aim of the research study was to analyse the implementation of the Zibambele Road Maintenance Programme within the KwaZulu-Natal Department of Transport. The Zibambele Programme is one of South African government attempts to respond to social problems of poverty and unemployment. The Zibambele Programme identifies with the principles of Expanded Public Works Programme (EPWP). The research study identifies and discusses the obstacles to and challenges of the implementation of the Zibambele Road Maintenance Programme. Programme monitoring or process evaluation is used as an analytical framework of the study. The study employs Rossi and Freemans (1989) approach by examining the admission of the contractors into the programme, their progression and exit strategies. In order to best accomplish the objectives of the study and to provide an informed and critical analysis on the implementation of the Zibambele Programme, the study used both qualitative and quantitative research methodologies i.e. triangulation. For the quantitative method data was collected using in depth interview questions (i.e. face-to-face interviews) with the KwaZulu-Natal Department of Transport officials. The officials that were interviewed fall under the development directorate within the Department and they are directly responsible for the implementation of the Zibambele Programme. Four officials participated in the interviews and purposive sampling was used. For the quantitative method, the survey data collection method was employed to collect data from the Zibambele contractors. The contractors were randomly collected from the Pietermaritzburg and Empangeni regions. The results of the interviews were not generalised to all Zibambele contractors. However, the findings collected were useful as far as the implementation process of the Zibambele Programme is concerned. Content analysis was used to analyse qualitative data and descriptive statistics using the SPSS programme was used to analyse the quantitative data. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

published_or_final_version / Public Administration / Master / Master of Public Administration

The problems associated with increased heavy grain truck traffic in rural regions were investigated. Both the short-run incremental costs of accelerated pavement replacement and the long-run incremental costs of upgrading low-volume highways were considered. A set of demand and traffic models was formulated which projects the annual flow of grain from each production zone in an impact region to each elevator, allocates the flows among truck-types, computes the annual trips, gross vehicle weights and axle weights, and assigns the truck trips to the highway network. A set of highway models was also formulated which computes the equivalent single axle loads for each highway section in an impact region and estimates the incremental costs associated with subterminal traffic. The impacts of a newly-formed subterminal-satellite elevator system in rural North Dakota were investigated. The results of the case study indicate that rural collector highways are likely to experience substantial localized impacts from subterminal development but the effects on principal arterials may be minimal. Altogether, $1.14 million in short-run costs and $8.41 million in long-run costs were projected for the impact region. However, the case study roads represent less than 2 percent of the rural arterial and collector highway mileage in the state. If the case-study network represents a microcosm of rural North Dakota, then the statewide short-run and long-run incremental costs may be in the vicinity of $57 million and $420 million respectively. However, regional variations within the state may result in either higher or lower costs for a given elevator system than those projected in the case study. / Ph. D.

This dissertation focuses on the development of data analytics approaches to two distinct important condition monitoring applications in civil infrastructure: structural health monitoring and road surface monitoring. In the first part, measured vibration responses of a major long-span bridge are used to identify its modal properties. Variations in natural frequencies over a daily cycle have been observed with measured data, which are probably due to environmental effects such as temperature and traffic. With a focus on understanding the relationships between natural frequencies and temperatures, a controlled simulation-based study is conducted with the use of a full-scale finite element (FE) model and four regression models. In addition to the temperature effect study, the identified modal properties and the FE model are used to explore both deterministic and probabilistic model updating approaches. In the deterministic approach (sensitivity-based model updating), the regularization technique is applied to deal with a trade-off between natural frequency and mode shape agreements. Specific nonlinear constraints on mode shape agreements are suggested here. Their capabilities to adjust mode shape agreements are validated with the FE model. To the best of the author's knowledge, the sensitivity-based clustering technique, which enables one to determine efficient updating parameters based on a sensitivity analysis, has not previously been applied to any civil structure. Therefore, this technique is adapted and applied to a full-scale bridge model for the first time to highlight its capability and robustness to select physically meaningful updating parameters based on the sensitivity of natural frequencies with respect to both mass and stiffness-related physical parameters. Efficient and physically meaningful updating parameters are determined by the sensitivity-based clustering technique, resulting in an updated model that has a better agreement with measured data sets. When it comes to the probabilistic approach, the application of Bayesian model updating to large-scale civil structures based on real data is very rare and challenging due to the high level of uncertainties associated with the complexity of a large-scale model and variations in natural frequencies and mode shapes identified from real measured data. In this dissertation, the full-scale FE model is updated via the Bayesian model updating framework in an effort to explore the applicability of Bayesian model updating to a more complex and realistic problem. Uncertainties of updating parameters, uncertainty reductions due to information provided by data sets, and uncertainty propagations to modal properties of the FE model are estimated based on generated posterior samples. In the second part of this dissertation, a new innovative framework is developed to collect pavement distress data via multiple vehicles. Vehicle vibration responses are used to detect isolated pavement distress and rough road surfaces. GPS positioning data are used to localize identified road conditions. A real-time local data logging algorithm is developed to increase the efficiency of data logging in each vehicle client. Supervised machine learning algorithms are implemented to classify measured dynamic responses into three categories. Since data are collected from multiple vehicles, the trajectory clustering algorithm is introduced to integrate various trajectories to provide a compact format of information about road surface conditions. The suggested framework is tested and evaluated in real road networks.

Workers have the right to a safe working environment. This right is encapsulated in the Bill of Rights (1996) wherein strong emphasis is placed on the right to a healthy and safe work environment. The construction industry has been labeled as dangerous owing to regular incidents, serious accidents, and fatalities. Road workers’ safety is at high risk in road construction areas, as they perform their work activities alongside moving vehicles that are often large and sometimes moving at high speed. It was determined that very few secondary sources provided information regarding the safety of South African road construction workers. Therefore, the knowledge obtained from this study contributes to the body of knowledge on the subject matter. To collect data, three descriptive surveys were conducted on two different road construction projects within the Eastern Cape. The survey participants included engineering consultants, contractors, traffic safety officers, general road construction workers, as well as random motorists driving through the work zone. Further data was collected from a speed measuring instrument placed in the work zone of the Port Elizabeth. The findings of this research report indicate that road users are not cognizant of the risk to workers in the work zone and that signage and advance warning signs alone are not sufficient to slow motorists’ speed. A further significant threat to road worker safety, is plant operator visibility. This study recommends that government and construction firms educate the public regarding the risks associated with speeding through a work zone. Construction firms should use electronic speed measuring devices prior to the work zone to make road users aware of their speed in relation to the speed limit. To limit plant related accidents, companies should install sensors or cameras on the rear and side panels of plant, so that plant operators have all round vision. Furthermore, road workers could be educated on the controlled use of their mobile phones to reduce the risks associated with the use of mobile phones inside work zones.