Development of Technological Solutions for Sewer Rehabilitation Using Clinker Brick

The aim of the work is to develop a technology for the restoration of damaged sections of sewer collectors using clinker bricks. A significant part of such collectors in the Ukraine has completely exhausted their depreciation resource. For their construction, concrete and reinforced concrete were used, which are subject to destruction as a result of the influence of many factors and, above all, microbiological corrosion. Therefore, the selection of the optimal repair technology using corrosion-resistant clinker brick is relevant. The paper considers the problems of repair and reconstruction of worn-out collectors. Technical and technological solutions of an open method for their recovery using pneumatic formwork and corrosionresistant clinker brick are presented. The design of the collector lining structure has been carried out using the finite element method. To justify the feasibility of using the proposed technology, two options for restoring a worn-out collector have been considered: the “pipe-in-pipe” method and method developed by the authors using clinker bricks. The second option in terms of the cost of materials is almost four times more economical and more expedient than the first one (where polymer materials are used). The advantage of restoring circular sewer collectors by means of laying clinker bricks lies in the durability and resistance of this material (taking into account the anticorrosive composition of concrete) to the aggressive effects of the sewer environment. It should be noted that the application of the developed restoration technology is the most appropriate in conditions of sparse building or outside the city due to the significant volume of earthworks.

Methodology for the Selection of Trenchless Sewer Rehabilitation Technologies in Bogotá, Colombia

Context: Operational and/or structural failures in sewer networks lead network operators to carry out rehabilitation tasks to maintain water transport conditions, which is why it is necessary to decide on the type of intervention to be performed, that is, i) a traditional open-ditch procedure, or ii) the use of trenchless rehabilitation technologies. Objective: This article focuses on the methodology developed and implemented in the SELECTOR program, whose purpose is to provide public service companies responsible for sewer service, as well as related professionals, with a decision tool that answers, from a technical perspective, which of the analyzed trenchless rehabilitation technologies (pipe bursting, cured-in-place pipe, slip lining, and spiral wound) is the most suitable for the rehabilitation of sewer networks. Method: To this effect, it is necessary ​​to consider all the influence parameters at the time of sewer rehabilitation, define the application ranges of these trenchless technologies, extract the differential variables, use fuzzy logic verbalization, determine the priority and relationship between the variables using the data mining technique known as decision trees, and develop the SELECTOR program by means of the Visual Studio 2017® platform. Results: The differential variables for decisions regarding the application of trenchless rehabilitation technologies in underground sewerage infrastructure projects were identified. A graphic summary of the decision model was made using the verbalization diagrams and the SELECTOR program, which allows processing the information of the sewerage networks individually and for a whole sewer rehabilitation project, detailing the intervention collector to collector. Conclusions: There are eight differential variables when deciding on sewer rehabilitation. Verbalization diagrams allow to compress the decision model and facilitate its programming, and automated decision models increase effectiveness and transparency in construction processes.

Using deterioration modelling to simulate sewer rehabilitation strategy with low data availability

Most cities face the problem of an aging infrastructure in need of extensive and ongoing repair, renovation or replacement. Since the 1980's, CCTV is the industry standard for sewer system inspection and the main source of information for structural performance evaluation. Due to low inspection rates and the lack of information about sewer condition, deterioration models have been developed to simulate the condition of non-inspected sewers and assess the influence of several rehabilitation scenarios. This paper presents an innovative modelling tool for long-term sewer rehabilitation planning based on the integration of a deterioration and a rehabilitation model. The tool is demonstrated in full scale using CCTV and sewer data of the city of Sofia, in Bulgaria. Results provide tangible proofs of investments needs for sewer rehabilitation and support the utility in the negotiation of budgets with the municipality. Since age is a one of key variable for deterioration modelling, a new method is proposed to estimate missing construction years in the utility database with a prediction error of less than 7 years.