Rural road management in Botswana

This paper discusses the management of rural roads in Chobe in Botswana, which are mainly tertiary and access roads. These roads are low-volume roads and mostly gravelled. It was observed that the maintenance management of these roads was based on engineering judgement through visual inspection all over the country, without having any economic or technical analysis. Therefore, a comprehensive pavement management system for rural roads' maintenance is needed in Chobe and also in all the council areas of Botswana, which would consist of data collection, database, use of the Highway Development and Management Model to undertake efficient decision making project preparation, funding, implementation and feedback. A partial implementation of pavement management system in Chobe has been highlighted in this paper. The present analysis reveals that total demand for the road network in Chobe was 41·29 million pula, the backlog was 34·86 million pula and the first-year backlog demand was 20·63 million pula. Furthermore, the analysis found the long-term periodic maintenance strategy for the network at 6·43 million pula when there is no backlog. This huge backlog indicates that roads are not being maintained appropriately. The paper also estimates current road asset value in Chobe at 55·48 million pula. Finally, the paper recommends several solutions for the efficient preservation of road assets in Botswana

BEASAC - A Survey Hovercraft for Observing the Beaches and Offshore Areas Near the Belgian Coast

In 1983, the Belgian Government instructed the Belgian company Eurosense to start with the development of a new hydrographic measuring system: a specially designed hovercraft-based sounding system. After a period of extended testing, the craft and its special purpose hardware and software was accepted in 1985 by the Coastal Hydrographic Office of the Belgian Ministry of Public Works. Now the system is successfully employed for monitoring changes to access channels of the major Belgian sea ports and for supervising the extensive dredging activities. Moreover, it is used to observe the beaches and offshore areas near the Belgian coast

Automobile and Motorcycle Traffic on Indonesian National Roads: Is It Local or Beyond the City Boundary?

経済学 / EconomicsThis paper investigates the dimensions of private vehicles\u27 trips on national roads between neighboring cities in Indonesia using the spatial lag model and the spatial error model approach to reveal the spatial correlations among cities. Private vehicles are defined as privately owned automobiles and motorcycles, and vehicle trips or usage levels are defined in terms of vehicle kilometers traveled (VKT) for both types of private vehicles. The paper finds that motorcycle trips are characteristically local because there is no sign of a spatial correlation with neighboring cities for those trips; by contrast, automobile trips often cross city boundaries, although the models constructed in this study demonstrate only weak spatial correlations among neighboring cities for automobile trips. The models also indicate that the road capacity, gasoline prices, gross domestic regional product per capita, population density, city size, number of public buses, and worker resident density have a significant effect on VKT for both cars and motorcycles. Therefore, these findings suggest that in general, the design of urban transportation policies on national roads could be less complex in Indonesian cities because local solutions may be effective for solving traffic problems in individual cities.JEL Classification Codes: R41, R49, R53http://www.grips.ac.jp/list/jp/facultyinfo/yoshida_yuichiro

A laboratory study on cold-mix, cold-lay emulsion mixtures

This paper describes laboratory experiments and presents results for the performances of cold-mix, cold-lay emulsion mixtures. The main objective of the experiments was to evaluate and improve the properties of the cold mixtures. The mixture properties evaluated were: volumetric properties, indirect tensile stiffness modulus (ITSM), repeated load axial creep and fatigue. These properties were compared with conventional hot asphalt mixtures not containing any waste/recycled materials. To optimise the performances of the mixtures, a target of ITSM value of 2000 MPa was selected. At full curing conditions, the stiffness of the cold mixes was found to be very similar to that of hot mixtures of the same penetration grade base bitumen (100 pen). Test results also show that the addition of 1–2% cement significantly improved the mechanical performance of the mixes and significantly accelerated their strength gain. The fatigue behaviour of the cold mixes that incorporated cement was comparable with that of the hot mixtures

Contribution to sustainable seismic design of reinforced concrete members through embodied CO2 emissions optimization

The embodied CO2 emissions of reinforced concrete (RC) structures can be significantly reduced by structural optimization that maximizes structural efficiency. Previous studies dealing with design of RC structures for minimum CO2 emissions do not address seismic design provisions. This is the case despite the fact that in many countries around the world, including most of the top-10 countries in CO2 emissions from cement production, RC structures have to be designed against earthquake hazard. To fill a part of this gap, this study, using exhaustive search, examines optimum designs of RC beam and column members for minimum embodied CO2 emissions according to Eurocode-8 for all ductility classes and compares them with optimum designs based on material cost. It is shown that seismic designs for minimum CO2 footprint lead to less CO2 emissions but are more expensive than minimum cost designs. Their differences strongly depend on the assumed values of the environmental impact of reinforcing steel and concrete materials. Furthermore, it is concluded that seismic design for high ductility classes can drive to significant reductions in embodied CO2 emissions

Climate change adaptation in practice: People's responses to tidal flooding in Semarang, Indonesia

In many places in the world the effects of common floods are increased by climate change. In the area around the Indonesian city of Semarang, the number and effects of tidal flooding are becoming more and more severe. We found that the inhabitants used different strategies against the impact of flooding. In both the existing and the predicted flood prone areas, most people appear not to intend to leave the area, even when the floods become everyday routine. People are connected to their dwellings in a way that abandoning is not a realistic scenario. This study provides relevant information about the way people in the affected areas perceive flood risks and adaptation opportunities. Governmental policy-makers and urban planners could base their strategies and actions on this information. © 2011 The Authors. Journal of Flood Risk Managemen

The indispensability of good operation & maintenance (O&M) manuals in the operation and maintenance of low carbon buildings

Increase in energy usage, particularly from fossil fuel sources is widely understood to be responsible for the environmental problems (Climate Change) experienced globally today. Response to mitigating this anthropogenic induced consequence created the need for innovative low carbon and renewable technologies in buildings. In the UK presently, every new building is expected to be low-carbon and energy-efficient. However, it is widely acknowledged that significant differences often exist between designed and in-use performances of the buildings. Clients and end-users of these technologies appear not to be getting long term value for their investments; much attention has not been given to how these innovative technologies can be operated and maintained long into the future. Recent researches also underpin the fact that the wide information gap existing between designers and building end-users is one of the factors responsible for the performance-gap. This paper therefore presents excerpts of a research aimed at exploring a best practice approach to operability and maintainability of low-carbon-buildings. The research methodology involved the use of interviews, surveys and case study. Findings suggest that a properly prepared O&M manual is a potential document that that could bridge this gap and that it is an indispensable tool for the effective and efficient operation and maintenance of low carbon buildings

Proceedings of the national workshop on wastewater management and decentralised wastewater treatment systems (DEWATS) in Lao PDR, 6-7 October 2014

The Ministry of Public Works and Transport (MPWT) with support from UNESCAP and UN-HABITAT has organised the national work shop on 6-7 October, 2014, to take stock of the current situation and to enhance existing strategies and policies with mechanisms o

An Evaluation of the Resilient Modulus and Permanent Deformation of Unbound Mixtures of Granular Materials and Rubber Particles from Scrap Tyres to Be Used in Subballast Layers

[EN] Over the last years rubber from scrap tyres has been reused in different civil works such as road embankments and railway platforms due to its resilient properties, low degradation and vibration attenuation. Unfortunately, this issue is still scarce. For instance, in Spain about 175.000 tonnes of scrap tyres were collected in 2014, of which only 0.6% were reused in civil works. Aiming to contribute to the reutilisation of large quantities of this waste material, this paper focuses on the analysis of unbound mixtures of granular materials with different percentages of rubber particles to be used as subballast layers. Mixtures are tested under cyclic triaxial tests so as to obtain their resilient modulus and evaluate their permanent deformations. It is found that as the rubber content increases, the resilient modulus decreases and the permanent deformation increases. Taking into account the usual loads transmitted to the subballast layer, the optimum rubber content that does not compromise the behaviour of the mixture is set in a range between 2.5% and 5% in terms of weight. (C) 2016 The Authors. Published by Elsevier B.V.Hidalgo Signes, C.; Martínez Fernández, P.; Garzón-Roca, J.; Garrido De La Torre, ME.; Insa Franco, R. (2016). An Evaluation of the Resilient Modulus and Permanent Deformation of Unbound Mixtures of Granular Materials and Rubber Particles from Scrap Tyres to Be Used in Subballast Layers. Transportation Research Procedia. 18:384-391. doi:10.1016/j.trpro.2016.12.050S3843911