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Nov 24, 2004 In view of the selection possibilities as well as the very involved piping-specific bordering conditions and other factors to be taken into account (such as structures, plant growth and traffic), the provision of decision aids that make it possible to choose the best possible structural rehabilitation process for application cases while taking process-technical, ecological, economic and legal considerations into account becomes increasingly important. |
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Nov 24, 2004 Engineering services are technical intellectual services that offer individual solutions for single-case tasks. They are not subject to the "Verdingungsordnung für Bauleistungen" German Contract Procedures for Building Works (VOB) [VOB92] nor the "Verdingungsordnung für Dienstleistungen" German Contract Procedure in the Service Industry (VOL) [VOL97]. These services are generally awarded by private contract letting according to the following selection … |
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An important feature of a proposal request based on a contract requirement with a specification sheet is that the technical planning phase of the measures to be adopted in sewage construction is generally already completed. The instructing party must describe the service so comprehensively on the basis of the planned construction proposal that all tenderers understand the description in the same way and can calculate their prices without comprehensive … |
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According to VOB/A ยง 9 Nos. 10-12, there is also the possibility of throwing open the proposal for the building works to competition. In this well-known proposal request process, also known as functional proposal request, the description of the service is also provided by the tenderer. The obligatory results contract of the instructing party describes the purpose of the completed service and should present a detailed description of the required construction … |
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What type of contract requirements in a proposal request is finally deemed to be "more suitable" for the particular case depends on a multitude of factors. The more the planning is moved into the proposal request, the more the proposal request should move in the direction of the obligatory results programme. If one views the present proposal request practice in the execution of sewer rehabilitation, then one finds that §, in comparison with new sewer … |
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Nov 24, 2004 The ATV-M 143 Part 5 [ATVM143-5a] has the aim that all tenderers understand the contract requirements when applied to the relining process according to ATV-M 143E Part 3 [ATVM143-3] unambiguously, that they can calculate their prices with safety and that they can avoid differences in competitiveness. This specification pamphlet can also be used as a base for other rehabilitation processes for repair of damage until other process-specific specifications … |
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Nov 24, 2004 The guidelines of the AGI [AGI94a] contain keyword listed individual services divided into the following sections:
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Nov 24, 2004 The "Gemeinsame Ausschuss Electronik im Bauwesen" (Combined Committee for Electronics in Construction) (GAEB) has taken on the task of promoting rationalisation in the construction field by means of data processing. They deal with the federal and the state sectors, the main communal associations as well as the main organisations of industry and technology that are concerned with construction work. The GAEB is involved wherever matters of construction … |
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Feb 16, 2011 Standard specification book - LB 309: "Reinigung und Inspektion von Abwasserkanälen und -leitungen" (Cleaning and inspection of drains and sewers) |
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Feb 16, 2011 (Image: Example of a specification position from the standard specification book LB 310 (Standard service number STL-No. 310/080 2102) [LB310]) This specification section of the StLB [LB309] also limits itself to non-man-accessible drains and sewers. It comprises exclusively the process groups "Repair" and "Renovation". The structure of the LB 310 is based on the idea that before its application, the selection of the process has already been carried … |
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In order that specification sheets for the rehabilitation of sewers can be laid down in a professional and safe manner and that they contain all the information to enable the tenderer to work out a price and to execute the work, aids to proposal requests have been developed by various institutions in the past years, such as:
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Nov 24, 2004 In the Federal Republic of Germany, the federal, the states and community administrators as well as a large number of non-public developers make use of the "Verdingungsordnung für Bauleistungen" (VOB) (Contract Procedures for Building Works) in the purchase of building works [VOB92]. The VOB provides rules for the procedure for the contract letting of public building contracts and formulates general contract conditions, which place the rights and … |
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Nov 24, 2004 |
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Jul 26, 2005 Starting point of each qualified network analysis is an extensive analysis of the actual condition of the network or network part looked at. Here, it has to be considered that the significance of following predictions decisively depends on the completeness and consistency of the data taken as a basis as well as their analysis within the scope of the evaluation of the actual condition. For this reason, previous to the start of the evaluation of the … |
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Jul 26, 2005 The aging process of drain and sewer systems depends on a variety of influencing factors and interdependencies similar to the lifetime of humans and cannot be grasped mathematically for a specific individual case. For the aging prediction the observed network aging of the past is mathematically represented instead and extrapolated into the future. For that purpose the cohort survival model, which was developed in demography, is applied [Truji95]. … |
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Jul 20, 2005 Whereas the survival functions illustrate the average aging behaviour of single characteristic groups which has been observed in the past, an extended analysis is necessary for the condition- and substance predictions of a network and single network elements. Here the foundation of the substance- as well as the condition predictions is provided by the survival functions determined in Abschnitt 5.7.1.1.1.1.2 as well as by the mathematical model of … |
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Jul 20, 2005 The accuracy of the prediction correlates with the quality and the extent of the available inspection data. The following differentiations can be made in the condition- and substance predictions:
The procedure of the section-related prediction is illustrated in the following by means of a case model for the substance prediction of an inspected section. An inspected, ten-year-… |
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Jul 26, 2005 Since the long-term prediction presents a vital basis of modern rehabilitation planning, it is indispensable to ensure a corresponding prediction quality. On the one hand the predictions are to provide similar results with similar data and thus are to be steady. On the other hand the results are to illustrate the real network aging process as precisely as possible. The prediction quality can be checked with the help of available re-inspections by ex-… |
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Jul 26, 2005 |
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Jul 26, 2005 The prediction model "STATUS-Sewer" forms a solid basis for analyses of effectiveness of decisions for rehabilitations. By giving budget sizes, ecologic and hydraulic requirements as well as further network-specific limiting conditions, various strategies can be investigated exhaustively concerning their effects on the substance development, the rehabilitation costs, the fees etc. Here the prediction of the network-specific aging processes allows … |
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Jul 26, 2005 Priority string At present short-term rehabilitation plannings are carried out on the basis of a priority list, e.g. according to ATV-M 149 [ATVM149a] or KAPRI [Mölleb]. Due to the lacking or marginal consideration of the initially described section substance as well as section-related limiting conditions wrong decisions are likely to develop in the operative planning process. In "STATUS-Sewer" especially the differentiated constructional evaluation … |
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Jul 26, 2005 |
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The rehabilitation of drain and sewer systems is a continuous task due to the extent of the measures necessary and the financial means that have to be introduced. For this reason it requires long-term and future-oriented strategies. The integral challenge in the development of strategies is to find a way which ensures the preservation of a network's substance for the following generations within the conflict area of budget restrictions, fees and other … |
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(Image: Possibilities for influences of cost during the course of a project [Bohn96]) The network-oriented investigations are subject to economic efficiency testing for projects. In both cases the owner of the installations has the duty of decisions that cannot finally be passed on to anybody else. Thus, it is important to use practicable methods for economic efficiency testing. Bild 5.7.1.1.2 shows the large influence of costs, especially in the … |
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