Presentation on theme: "KRAH AG : STRUCTURED WALL PIPE TECHNOLOGY"— Presentation transcript:
1 KRAH AG : STRUCTURED WALL PIPE TECHNOLOGY WISA Appropriate Technology Conference, Cape Town3 September 2007Please visit
2 Who and What is Krah? Krah AG of Germany commenced 1969 40 polyolefin pipe plants worldwideReference list over 260 major projectsStructured wall - gravity pipelines (KPS)Structured wall - pressure pipes (KPPS)Diam mm- 16kN/m2 or 2500kPaComply with applicable standardsStandard pipe designs profilesCustomised designs can be computedAPPROPRIATE for SA CONDITIONS
4 What are the Attributes? Good hydraulics – smooth inner surfaceTough – abrasion and impact resistanceChemical resistance – chemically inertInspection friendly – bright yellow linerSafe joint – integrated electro-fusionFlexible – will flex not fractureLight weight – fast cheap constructionDesign is a permutation of 5 attributes100 year life – environmentally correctAPPROPRIATE for INFRASTRUCTURE
6 Are the Designs and Standards Adequate? Hydraulic design ATV-DVWK-A110E a 79 page comprehensive document Sept. 2001Structural design ATV-DVWK-A127E a 91 page comprehensive document Aug. 2000Dimensions and Technical DIN /2System specification prEN /2/3Design software includes all in-situ soil strength in the “soil pipe structure”Manufacture control software integrated with design software to prevent errors.APPROPRIATE TECHNOLOGY for SA
10 Is It a Complete System?Bends, branches, laterals, reducers, house connections and in-line or tangential manholesDesign software “Easy Pipe” integrated with manufacturing software “Mickey”Complete design detail submitted to client for adjudication and approvalElectro-fusion bar code in each socketJoint clamped; pressure + temperatureTraceability of every weld and pipe
12 RESULTS OF EASY PIPE DESIGNS RUN 1: Standard InstallationThis is typical the in excess one that is done when data are not had on the work, assuming conditions of standard installation.RUN 2: Very Low cover depthsIn this run the value of the minimum cover depths is modified, taking minimun value accepted by EASY PIPE, that is 0.5 mts.RUN 3: Very deep cover depthsIn this run the value of the max. Cover depths, taking it to 7.00 is modified mtsRUN 4: Water tableIn this run the water table is added, to a height of 2 mts over the max. level of the seat bed.RUN 5: Combination of all RUNSHere all the changes done in the previous runs are put into play, is to say the parameters of RUN 1 but changing: the minimum cover depth to 0.5 mts, the Maxima cover depth to 7.00 mts and 2.00 the water table level to mts over the seat bed.
14 Please visit www.krah.net CONCLUSIONSThe results show that, contrary to the intuition, the annular rigidity that need the tubes for certain condition of installation he is not constant, but that will depend on the diameter of such (to see graph). This must to the different interaction tube-settles (fundamental to obtain a joint package structural) that takes place in each measurement and thus it demonstrates that the rigidity of the tube only has an intervention limited in the structural resistance of the set.Take note also how it substantially increases to the necessary rigidity before the combination of high cover depth and water table, which increases exponentially when the phreatic level rises.Please visit