986 resultados para Road construction contracts.


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The BPR type Roughometer has been used by the Iowa State Highway Commission since 1955 for the evaluation of the relative roughness of the various Iowa road surfaces. Since the commencement of this program, standardized information about the roughness of the various Iowa roads with respect to their type, construction, location and usage has been obtained. The Roughometer has also served to improve the economics and quality of road construction by making the roughness results of various practices available to all who are interested. In 1965, the Portland Cement Association developed a device known as the PCA Road Meter for measuring road roughness. Mounted in a regular passenger car, the Road Meter is a simple electromechanical device of durable construction which can perform consistently with extremely low maintenance. In 1967, the Iowa State Highway Commission's Laboratory constructed a P.C.A. type Road Meter in order to provide an efficient and reliable method for measuring the Present Serviceability Index for the state's highways. Another possibility was that after considerable testing the Road Meter might eventually replace the Roughometer. Some advantages of the Road Meter over the Roughometer are: (1) Road Meter tests are made by the automobile driver and one assistant without the need of traffic protection. The Roughometer has a crew of four men; two operating the roughometer and two driving safety vehicles. (2) The Road Meter is able to do more miles of testing because of its faster testing speed and the fa.ct that it is the only vehicle involved in the testing. (3) Because of the faster testing speed, the Road Meter gives a better indication of how the road actually rides to the average highway traveler. (4) The cost of operating a Road Meter is less than that of a Roughometer because of the fewer number of vehicles and men needed in testing.

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Several road construction projects involving concrete overlays at the state and county levels in Iowa in 2009 were studied for construction techniques and methods. The projects that were evaluated consisted of sites in four Iowa counties: Osceola, Worth, Poweshiek, and Johnson counties. The construction techniques and methods that were studied included concrete overlays and material usage. By evaluating these methods, highway agencies can explore different ways of making road construction less costly and can minimize the amount of time that the traveling public is exposed to road construction.

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Fly ash, a by-product of coal-fired electricity generating plants, has for years been promoted as a material suitable for highway construction. Disposal of the large quantities of fly ash produced is expensive and creates environmental concerns. The pozzolanic properties make it promotable as a partial Portland cement replacement in pc concrete, a stabilizer for soil and aggregate in embankments and road bases, and a filler material in grout. Stabilizing soils and aggregates for road construction has the potential of using large quantities of fly ash. Iowa Highway Research Board Project HR-194, "Mission-Oriented Dust Control and Surface Improvement Processes for Unpaved Roads", included short test sections of cement, fly ash, and salvaged granular road material mixed for a base in western Iowa. The research showed that cement fly ash aggregate (CFA) has promise as a stabilizing agent in Iowa. There are several sources of sand that when mixed with fly ash may attain strengths much greater than fly ash mixed with salvaged granular road material at little additional cost

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Recent developments in contracting practice in the UK have built upon recommendations contained in highprofile reports, such as those by Latham and Egan. However, the New Engineering Contract (NEC), endorsed by Latham, is based upon principles of contract drafting that seem open to question. Any contract operates in the context of its legislative environment and current working practices. This report identifies eight contentious hypotheses in the literature on construction contracts and tests their validity in a sample survey that attracted 190 responses. The survey shows, among other things, that while partnership is a positive and useful idea, authoritative contract management is considered more effective and that “win-win” contracts, while desirable, are basically impractical. Further, precision and fairness in contracts are not easy to achieve simultaneously. While participants should know what is in their contracts, they should not routinely resort to legal action; and standard-form contracts should not seek to be universally applicable. Fundamental changes to drafting policy should be undertaken within the context of current legal contract doctrine and with a sensitivity to the way that contracts are used in contemporary practice. Attitudes to construction contracting may seem to be changing on the surface, but detailed analysis of what lies behind apparent agreement on new ways of working reveals that attitudes are changing much more slowly than they appear to be.

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The cost of a road construction over its service life is a function of the design, quality of construction, maintenance strategies and maintenance operations. Unfortunately, designers often neglect a very important aspect which is the possibility to perform future maintenance activities. The focus is mainly on other aspects such as investment costs, traffic safety, aesthetic appearance, regional development and environmental effects. This licentiate thesis is a part of a Ph.D. project entitled “Road Design for lower maintenance costs” that aims to examine how the life-cycle costs can be optimized by selection of appropriate geometrical designs for the roads and their components. The result is expected to give a basis for a new method used in the road planning and design process using life-cycle cost analysis with particular emphasis on road maintenance. The project started with a review of literature with the intention to study conditions causing increased needs for road maintenance, the efforts made by the road authorities to satisfy those needs and the improvement potential by consideration of maintenance aspects during planning and design. An investigation was carried out to identify the problems which obstruct due consideration of maintenance aspects during the road planning and design process. This investigation focused mainly on the road planning and design process at the Swedish Road Administration. However, the road planning and design process in Denmark, Finland and Norway were also roughly evaluated to gain a broader knowledge about the research subject. The investigation was carried out in two phases: data collection and data analysis. Data was collected by semi-structured interviews with expert actors involved in planning, design and maintenance and by a review of design-related documents. Data analyses were carried out using a method called “Change Analysis”. This investigation revealed a complex combination of problems which result in inadequate consideration of maintenance aspects. Several urgent needs for changes to eliminate these problems were identified. Another study was carried out to develop a model for calculation of the repair costs for damages of different road barrier types and to analyse how factors such as road type, speed limits, barrier types, barrier placement, type of road section, alignment and seasonal effects affect the barrier damages and the associated repair costs. This study was carried out using a method called the “Case Study Research Method”. Data was collected from 1087 barrier repairs in two regional offices of the Swedish Road Administration, the Central Region and the Western Region. A table was established for both regions containing the repair cost per vehicle kilometre for different combinations of barrier types, road types and speed limits. This table can be used by the designers in the calculation of the life-cycle costs for different road barrier types.

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The cost of a road construction over its service life is a function of design, quality of construction as well as maintenance strategies and operations. An optimal life-cycle cost for a road requires evaluations of the above mentioned components. Unfortunately, road designers often neglect a very important aspect, namely, the possibility to perform future maintenance activities. Focus is mainly directed towards other aspects such as investment costs, traffic safety, aesthetic appearance, regional development and environmental effects. This doctoral thesis presents the results of a research project aimed to increase consideration of road maintenance aspects in the planning and design process. The following subgoals were established: Identify the obstacles that prevent adequate consideration of future maintenance during the road planning and design process; and Examine optimisation of life-cycle costs as an approach towards increased efficiency during the road planning and design process. The research project started with a literature review aimed at evaluating the extent to which maintenance aspects are considered during road planning and design as an improvement potential for maintenance efficiency. Efforts made by road authorities to increase efficiency, especially maintenance efficiency, were evaluated. The results indicated that all the evaluated efforts had one thing in common, namely ignorance of the interrelationship between geometrical road design and maintenance as an effective tool to increase maintenance efficiency. Focus has mainly been on improving operating practises and maintenance procedures. This fact might also explain why some efforts to increase maintenance efficiency have been less successful. An investigation was conducted to identify the problems and difficulties, which obstruct due consideration of maintainability during the road planning and design process. A method called “Change Analysis” was used to analyse data collected during interviews with experts in road design and maintenance. The study indicated a complex combination of problems which result in inadequate consideration of maintenance aspects when planning and designing roads. The identified problems were classified into six categories: insufficient consulting, insufficient knowledge, regulations and specifications without consideration of maintenance aspects, insufficient planning and design activities, inadequate organisation and demands from other authorities. Several urgent needs for changes to eliminate these problems were identified. One of the problems identified in the above mentioned study as an obstacle for due consideration of maintenance aspects during road design was the absence of a model for calculating life-cycle costs for roads. Because of this lack of knowledge, the research project focused on implementing a new approach for calculating and analysing life-cycle costs for roads with emphasis on the relationship between road design and road maintainability. Road barriers were chosen as an example. The ambition is to develop this approach to cover other road components at a later stage. A study was conducted to quantify repair rates for barriers and associated repair costs as one of the major maintenance costs for road barriers. A method called “Case Study Research Method” was used to analyse the effect of several factors on barrier repairs costs, such as barrier type, road type, posted speed and seasonal effect. The analyses were based on documented data associated with 1625 repairs conducted in four different geographical regions in Sweden during 2006. A model for calculation of average repair costs per vehicle kilometres was created. Significant differences in the barrier repair costs were found between the studied barrier types. In another study, the injuries associated with road barrier collisions and the corresponding influencing factors were analysed. The analyses in this study were based on documented data from actual barrier collisions between 2005 and 2008 in Sweden. The result was used to calculate the cost for injuries associated with barrier collisions as a part of the socio-economic cost for road barriers. The results showed significant differences in the number of injuries associated with collisions with different barrier types. To calculate and analyse life-cycle costs for road barriers a new approach was developed based on a method called “Activity-based Life-cycle Costing”. By modelling uncertainties, the presented approach gives a possibility to identify and analyse factors crucial for optimising life-cycle costs. The study showed a great potential to increase road maintenance efficiency through road design. It also showed that road components with low investment costs might not be the best choice when including maintenance and socio-economic aspects. The difficulties and problems faced during the collection of data for calculating life-cycle costs for road barriers indicated a great need for improving current data collecting and archiving procedures. The research focused on Swedish road planning and design. However, the conclusions can be applied to other Nordic countries, where weather conditions and road design practices are similar. The general methodological approaches used in this research project may be applied also to other studies.

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Comparing the cost effectiveness of warranty vs. non-warranty road construction options for a 100 mile section of road over a 20 year period.

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verso: Nr. [near] Kalkaska

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Mode of access: Internet.

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Mode of access: Internet.

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The outcome of this research is an Intelligent Retrieval System for Conditions of Contract Documents. The objective of the research is to improve the method of retrieving data from a computer version of a construction Conditions of Contract document. SmartDoc, a prototype computer system has been developed for this purpose. The system provides recommendations to aid the user in the process of retrieving clauses from the construction Conditions of Contract document. The prototype system integrates two computer technologies: hypermedia and expert systems. Hypermedia is utilized to provide a dynamic way for retrieving data from the document. Expert systems technology is utilized to build a set of rules that activate the recommendations to aid the user during the process of retrieval of clauses. The rules are based on experts knowledge. The prototype system helps the user retrieve related clauses that are not explicitly cross-referenced but, according to expert experience, are relevant to the topic that the user is interested in.

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Debido a los cambios que se han dado en los sistemas de contratación en Colombia, para la ejecución de las obras de infraestructura que necesita el país, las responsabilidades frente a los riesgos han sido transferidas del Estado a los contratistas, salvo en el caso del riesgo geológico en la construcción de túneles, situación totalmente nueva, por cuanto en el pasado próximo, era el Estado el que resultaba siendo garante de las situaciones adversas que se presentaban durante la ejecución de los proyectos, por tanto, este hecho debe ser manejado de una manera seria y responsable por parte del contratista, de lo contrario es muy posible que en el camino se encuentre ante escenarios desfavorables que pueden afectar significativamente las finanzas de los ejecutores de dichos proyectos -- Se observa que en el caso del primer paquete de licitaciones de las mega obras, llamadas cuarta generación de concesiones, que el tema de riesgos no fue abordado de la manera como se debe hacer; las organizaciones participantes en dichos procesos se limitaron, en su gran mayoría, a solicitar asesoría a las aseguradoras, resultando análisis reducidos y direccionados hacia la venta de pólizas de seguros, cuando en realidad, el grueso de los riesgos que se deben asumir en este tipo de proyectos, no son asegurables, situación que posiblemente ha dejado desprotegidos a muchos de los constructores que resultaron ser adjudicatarios del mencionado paquete de licitaciones -- Debido a lo antes descrito, el autor de este trabajo decidió abordar el tema de los riesgos de otra manera, siendo más profundo en el análisis, y en primera instancia olvidándose de los seguros y las empresas aseguradoras -- Inicialmente, se pretendió hacer la identificación, clasificación y valoración de los riesgos encontrados, sin embargo, debido a lo extenso y complejo del tema, se hizo necesario repensar el alcance del trabajo de grado para optar al título de Magister en Gerencia Financiera, hasta la identificación de los riesgos en las diferentes etapas que comprende un proyecto de Alianza Público Privada o de concesión vial -- Quedan las puertas abiertas para que estudiantes de posgrado continúen este trabajo en las etapas de valoración y control de los riesgos identificados, no solo del área financiera, sino de riesgos, administración, o cualquier otra disciplina, que aborde tan interesante tema para profundizar, esto con el ánimo de cambiar la mentalidad del constructor colombiano que ha venido acostumbrado a no mirar el futuro con sentido de proyección y prevención de las tantas situaciones adversas que alteran el normal desarrollo de los macro proyectos de ingeniería

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Les méthodes de design et de construction des routes développés dans le sud canadien ont maintenant besoin d’être adaptés aux environnements nordiques du pays afin de prévenir le dégel dramatique du pergélisol lors de la construction d’une nouvelle route. De plus, le réchauffement climatique occasionne présentement d’importants problèmes de stabilité des sols dans le nord canadien. Ces facteurs causent des pertes importantes au niveau des capacités fonctionnelles et structurales de l’Alaska Highway au Yukon sur un segment de plus de 200 km situé entre le village de Destruction Bay et la frontière de l’Alaska. Afin de trouver des solutions rentables à long terme, le ministère du transport du Yukon (en collaboration avec le Federal Highway Administration du gouvernement américain, Transports Canada, l’Université Laval, l’Université de Montréal et l’Alaska University transportation Center) a mis en place 12 sections d’essais de 50 mètres de longueur sur l’autoroute de l’Alaska près de Beaver Creek en 2008. Ces différentes sections d’essais ont été conçues pour évaluer une ou plusieurs méthodes combinées de stabilisation thermique telles que le drain thermique, le remblai à convection d’air, le pare-neige / pare-soleil, le remblai couvert de matières organiques, les drains longitudinaux, le déblaiement de la neige sur les pentes et la surface réfléchissante. Les objectifs spécifiques de la recherche sont 1) d’établir les régimes thermiques et les flux de chaleur dans chacune des sections pour les 3 premières années de fonctionnement ; 2) de documenter les facteurs pouvant favoriser ou nuire à l’efficacité des systèmes de protection et ; 3) de déterminer le rapport coûts/bénéfices à long terme pour chacune des techniques utilisées. Pour ce faire, une nouvelle méthode d’analyse, basée sur la mesure de flux d’extraction de chaleur Hx et d’induction Hi à l’interface entre le remblai et le sol naturel, a été utilisée dans cette étude. Certaines techniques de protection du pergélisol démontrent un bon potentiel durant leurs 3 premières années de fonctionnement. C’est le cas pour le remblai à convection d’air non-couvert, le remblai à convection d’air pleine largeur, les drains longitudinaux, le pare-soleil / pare-neige et la surface réfléchissante. Malheureusement, des problèmes dans l’installation des drains thermiques ont empêché une évaluation complète de leur efficacité.

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This paper features a tool to carry out environmental performance evaluation in highway rehabilitation works, as a component of environmental supervision activities. The procedure involves (i) evidence gathering by conducting technical inspections and reviewing environmental compliance reports, (ii) ranking nonconformities according to a proposed weighting framework, and (iii) calculation of an environmental conformity index. For the sake of testing and calibration, the procedure was applied to five road segments that were submitted to rehabilitation works in Sao Paulo State and the results were treated qualitatively.