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The following table shows the DVGW working sheet GW 323 (Trenchless replacement of gas and water supply pipelines with pipe bursting; Requirements, quality assurance and inspections / not available in English at present) specified permissible tensile forces for PE 100 pipes for a load duration of 30 minutes. (Table: Permissible tensile forces for PE 100 pipes under a 30 min load [DVGWGW323]) |
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According to GW 323-4.3.2, the breaking strength of HD-PE is 2.5 times the permissible tensile stress [DVGWGW323]. The cross sectional area of a pipe section used as overload protection may only amount to 40 % of the cross sectional area of the new pipeline being pulled in. (Image: Overload protection in form of a predetermined breaking point by reduction of the wall thickness) (Table: Example calculation of an overload protection for HD-PE 100 used … |
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Illustrated example of the steps involved in the manufacturing of the overload protection in the form of a predetermined breaking point. (Image: Step 1: New pipeline) (Image: Step 2: Wall thickness reduction) (Image: Step 3: Welding on of the overload protection) (Image: Stept 4: Removing the weld seam) |
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A cross section reduction is obtained by reducing the effective circumference of pipe or the effective cross-sectional area. (Image: Overload protection in form of a predetermined breaking point by reduction of the effective pipe circumference) (Table: Overload protection) |
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May 27, 2019 |
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May 27, 2019 Congratulations! You have successfully finished this lesson. Next you will have the opportunity to review the newly acquired knowledge with an interactive questionnaire. You can of course still navigate back to any point in the lessons if you wish to review a specific point or subject. Stay curious! |
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May 27, 2019 This module is devoted to the pipe bursting as a special method of the replacement of pipelines. In addition, the module looks at the effects that pipe bursting has on the pipeline itself as well as its surrounding environment. Upon the successful completion of this module, you will be able to:
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May 27, 2019 AE-08 Replacement: Gallery Techniques (Heading) - Part III - Limiting Conditions BE-15 Replacement: Gallery Techniques (Heading) - Part III - Limiting conditions This lecture deals with the application fields and limits of gallery techniques (heading), the measures of quality assurance as well as the advantages and disadvantages of this process. |
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(Table: Material restrictions for gallery techniques (heading)) |
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(Table: Material restrictions for gallery techniques (heading)) |
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(Image: Documentation) Parallel to the ongoing construction measurement of the gallery, geotechnical measurements should be carried out before and during the construction process in order to confirm the positional stability of the gallery during the heading process. This is needed to detect potential ground deformations and to determine the effects on adjacent buildings. Surface levelings are suited for measurement methods to detect advancing or trailing … |
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(Image: Documentation) For the verification of the quality assurance of the applied materials and accomplished works, a QA-manual should be established by the contractor. The QA-manual should contain the following indications and verifications:
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Advantages of gallery techniques (heading):
Disadvantages of gallery techniques (heading):
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May 27, 2019 AE-08 Replacement: Gallery Techniques (Heading) - Part III - Limiting Conditions BE-15 Replacement: Gallery Techniques (Heading) - Part III - Limiting conditions Congratulations! You have successfully finished this lesson. Next you will have the opportunity to review the newly acquired knowledge with an interactive questionnaire. You can of course still navigate back to any point in the lessons if you wish to review a specific point or subject. Stay curious! |
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May 27, 2019 This module focuses on the fundamentals of the trenchless replacement of gas, water, wastewater pipelines using the gallery techniques known from the mining industry. In addition, the individual steps of the gallery heading process with steel and timber support are described - from the preparatory measures to the final work. In addition, the areas of application and limitations of gallery heading, the measures for quality assurance as well as the advantages and disadvantages of this method are presented. After completing this module, you will have a sound knowledge of:
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(Image: Sequence of operations work flow for pipe bursting) |
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(Image: Condition acquisition of a sewer via CCTV-inspection) (Image: Maintaining the drainage capability) (Image: Exposing a lateral connection using the open cut method as part of the bursting process) Pre-construction survey: The pre-construction survey includes a walkthrough at ground level of the pipeline sections to be replaced, to determe the location of existing pipelines and utilities in the surrounding area, as well as acquiring a visual assessment … |
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Pipeline cleaning, and removal of obstructions: Pipeline cleaning is not a required process as long as the pulling-in of the winch cable or the pulling rods is possible. If there are any obstructions preventing equipment access, e.g. pipe collapse, positional deviations, roots, etc., the pipeline must be cleared of such obstacles first. Preparation of the manholes: The manhole invert and connection areas must be prepared or modified in such a way that … |
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(Image: Documentation) Upon arrival at the construction site, the pipes are to be inspected for defects and damages. In addition, the delivery papers must be checked to ensure that the product corresponds with the original order details. These checks must be documented as part of the quality assurance procedure. (Image: HDPE discrete long pipes DA 20 in (500 mm)) |
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