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Appendix 2. Requirement pyramid - COST 337
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- Bu səhifədəki naviqasiya:
- Level 1: Requirements of interested parties / users; boundary conditions
- Level 2: Function / performance of the base during the road’s lifetime
- Level 3: The structural behaviour / properties of the base layer
- Behaviour Requirement
- Table A2.1: Structural behaviour requirements of a base layer Level 4: Material behaviour / properties
- Table A2.2: Material behaviour requirements Level 5: Material nature (particle)
- Nature Aspect of the particulate and physical nature of the materials
- Table A2.3: Required description of the particulate and physical nature of the materials
Appendix 2. Requirement pyramid - COST 337Requirement pyramid from COST 337 COST 337 present a structure in requirements for roads. It is a political pyramid and a technical pyramid, which has been publish by Dienst Weg- en Waterboukunde; Rijkswaterstaat (CROW in the Netherlands. Five levels in the pyramid are described. Following sections are from the draft final report, section 4.4 Functional and Structural Requirements from COST 337 (2002). Level 1: Requirements of interested parties / users; boundary conditions The requirements at level 1 are important for the road. These requirements are, however, not directly meant for base material, but are used to derive the requirements for base and sub-base layers. Interested parties and users of roads are very extensive groups. Not only the end-user is included, but also the financier, the contractor, the road-authority, persons and institutions in the direct surroundings of the road, and others directly affected by the road. The requirements and boundary conditions at this level are often complex and subjective. The following elements are distinguished at this level:
The definitions / descriptions of those elements are given below. The road has to satisfy or fulfil the following requirements: Safety The legal, traffic engineering and social requirements related to the safety of the road-user should be fulfilled. Comfort The evenness of the road should be such that the user experiences a level of comfort and serviceability consistent with the class of road. Environment The system of environmental, technical, public health regulations and boundary conditions related to the production and use of the building materials for the road should be fulfilled. The material or non-material (e.g., aesthetic) damage to the road’s surroundings (landscape, environment and nature), or to the neighbouring persons or buildings, during construction, during the road’s lifetime and eventually during demolition and reconstruction of the road should be within acceptable limits. Durability The road should be capable of withstanding the traffic loads during its calculated lifetime, within acceptable maintenance cost ranges. Economy The social cost (the balance) of the direct and indirect benefits and costs of construction, use, maintenance and demolition of roads should be adequate. Aesthetics The form and structure of the road built in the urban and rural landscape should harmonise with the landscape and social architecture. Traffic capacity The traffic capacity is the maximum possible traffic flow in stated units under ideal conditions. The geometry and the design of the road should be compatible with and complement the expected amount of traffic. Load transfer The pavement should be capable of transferring the traffic loads to the subgrade under all circumstances (frost, thaw, heavy rains, and high groundwater levels). The interruptions to the traffic flow during maintenance and reconstruction works should be within acceptable limits. Building materials policy The system of governmental regulations and boundary conditions related to the use of primary and reclaimed materials, as well as industrial waste products in road construction should be taken into account during the design and construction of the road. Public health considerations The system of governmental regulations and boundary conditions related to the working conditions during construction, maintenance and demolition of roads and the handling of building materials and equipment should be taken into account during the production, construction, and the maintenance and the eventual demolition of the road. Level 2: Function / performance of the base during the road’s lifetime The requirements of interested parties are often complex, subjective and indefinite. They have to be modified in terms of material-independent requirements, which are quantitative, if possible. Such functional requirements can be used in performance-related specifications. The authority can check the performance and the contractor has many possibilities to be innovative, for instance by using alternative materials or equipment. The next functional requirements for bases and sub-bases can be distinguished as: Realisation / construction process A. Technically realisable It should be possible to construct the road with available building materials, available techniques and within the available time. B. Safe (working conditions) and no harm for human health Risks during production of aggregates and during construction, maintenance, reconstruction and demolition of the road under valid safety and health regulations should always be acceptable. C. No inconvenience for surroundings during realisation During construction, maintenance and demolition, the inconvenience to the surroundings and neighbouring persons and institutions should be within acceptable limits. Bearing capacity (in terms of (maximum) loads)
During construction of the road, all separate construction layers should be passable for the building equipment under all or most circumstances. Exceptions may be frost, thaw, heavy rain, and high groundwater level. Good working platform (for applying the subsequent layer) It should be possible to apply the upper layers of the road pavement to the desired thickness and (compacted) densities on the existing layer. Reducing stresses / strains in the road construction The base should reduce the stresses / strains in the asphalt / concrete layers caused by the traffic loads to the maximum extent possible. Spreading loads on the sub-base / subgrade The base should spread the traffic loads and the weight of the upper layers of the road, pavement on the sub-base / subgrade in such a way that these loads will not lead to unacceptable deformation in the sub-base / subgrade during the lifetime of the road. Evenness The base should possess satisfactory longitudinal and transverse evenness during construction and during the lifetime of the pavement to provide a smooth ride, consistent with the importance of the road. Drainage The permeability of the base should be such that the layer is not affected by water during the construction of the road and during its service period. Re-use
At some time the road’s service life terminates and it is often then required to be demolished. When the road demolition stage is reached, it should be possible to remove the materials used for the base and sub-base in such a way that it will not cause harm to the environment. Materials reusable After demolition of the base and sub-base the materials obtained should be reusable for road construction or for other regenerative applications to the most favourable economic degree possible. Limitation of environmental damage during aggregate production and use
The effects of obtaining the materials to be used for the base and sub-base on nature, the scenery and the environment should be within acceptable limits. Using the material causes no damage to environment The effects of the application of the base and sub-base materials on nature, the scenery and the environment should be within acceptable limits. Reduced leaching The rate of pollution, due to the application of base and sub-base materials, on the soil, groundwater and surface water should be within acceptable limits. Groundwater management / resource The effect of the road construction on the existing groundwater system should be within acceptable limits. Costs The costs of sourcing, construction, maintenance, demolition, reuse and wastage of the unbound road materials should be affordable for the interested parties. Level 3: The structural behaviour / properties of the base layer The functional requirements are followed by the requirements for the behaviour of the construction under traffic loads. These requirements are related to the lifetime of the base layer, because normally there will be no maintenance carried out on the base layer during its lifetime. The expected lifetime of a base can be between 50 to 100 years, or even more, such as for instance the Via Apia Antica. The structural behaviour is determined by measurable properties obtained from laboratory testing, FWD and other NDT methods. Requirements for structural behaviour of the layer are listed in Table A2.1, following.
Table A2.1: Structural behaviour requirements of a base layer Level 4: Material behaviour / properties Elementary material behaviour can be divided into three main items:
The elementary material behaviour is mainly determined by the nature of the material, for instance, by the shapes of the particles of the material, which in turn affect the compactability of a material and its mechanical properties. The following material properties influence the behaviour of a base layer and sub-base layer: Requirements for the material behaviour of the layer are listed in Table A2.2.
Table A2.2: Material behaviour requirements Level 5: Material nature (particle) The level 5 requirements, for the nature of the material, concern the requirements related to chemical-mineralogical, physical and morphological (shape) aspects. Required descriptions of the particulate and physical nature of the materials comprising the layer are listed in Table A2.3.
Table A2.3: Required description of the particulate and physical nature of the materials Yüklə 0,7 Mb. Dostları ilə paylaş:
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