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Fig. 4: DN 700 HDD – Plan of locations and heights 2 The problems and how they were solved With all the requirements and constraints described, installation in open trenches could be dismissed straightaway. The old pipeline could not be replaced during operation, but operation needed to be maintained. Because of the restricted access routes, pipes of any great length were not an option and short assembly times were wanted. Laying out a string of pipes would have hampered access and consent had not been given for the pipeline to be floated out on the river. The experience which Berliner Wasserbetriebe had already had with ductile iron pipes on previous sections had been good. The relatively short laying lengths of 6 m were found to be an advantage on these. Angular deflections of the restrained joints would allow flexible adjustments to be made to cater for fixed points along the route. The horizontal direction drilling (HDD) technique was an elegant way of meeting these different requirements. After a critical check on 60 the costs, the consulting engineers doing the planning, Hyder Consulting GmbH Deutschland, also considered it the preferred technique. Experience with projects of a similar size abroad meant that there was even less of a risk. 3 Preparations for installation Berliner Wasserbetriebe’s project management department did the planning and took conscientious account of the interests and demands of all the parties involved and affected. A restricted invitation to tender with an open competitive pre-qualification procedure then selected the consortium to do the installation work and a further invitation to tender decided the pipe and fittings supplier. An order was placed for 504 m of ductile iron pipes to EN 545 [1] of wall-thickness class K 9 with TYTON® push-in sockets and the BLS®-/ VRS®-T restraint system and for the fittings required. The pipes are lined with cement mortar and on the outside are zinc coated with a rugged outer cement mortar coating to FGR® / EADIPS® 46
EN 15542 [2]. This coating withstands very high mechanical and chemical stresses. The joint regions are protected by heat-shrinkable tapes and sheet-metal cones. 4 The installation work – Part 1 Under the lead management of the Berlin branch of the Stehmeyer + Bischoff GmbH & Co. KG company, the preparatory work got under way: ■ drawing up and agreeing a timetable for installation, ■ setting up of the site, ■ digging of the launch pit lined with timber shoring, ■ surfacing/securing the site areas ■ dismantling/relaying a number of pipelines in the launch pits and target pits. The pilot bore and the following enlargement stages were the work of consortium member BLK-Bohrteam GmbH. The client required the allowable curve radius of 230.00 m (max. angular deflection at sockets 1.5°) to be kept to with absolute accuracy and to be documented by means of a cable-guided measuring system. While the drilling specialists were enlarging the diameter of the drilled bore, the target pit was dug and the line for the back-flushing fluid was set up. Work began early in November 2010. By the end of November, the bore had been enlarged first to 500 mm and then to 850 mm. The pipes were ferried from the storage point to the assembly pit on smaller vehicles. Fig. 5: High water on the Havel – Work in the flooded site area 5 Problems with the installation work Early in December 2010, the onset of winter forced the work to be suspended. Because of the frost there could be no guarantee of thorough back-flushing and the launch pits and target pits were also iced up. Another surprise was a historically high water level on the Havel, which meant that the track along the bank to the assembly pit was flooded (Fig. 5). The water even threatened to run into the assembly pit, which needed an extra safeguard in the form of sandbags. 6 The installation work – Part 2 Work resumed from mid-January 2011. The enlargement to 850 mm was repeated and the bore then bored out to 1,100 mm. The final clearing was done by a “cleaning pass” by a 6 m long DN 850 trial pipe and the bore was checked for free passage. The requirements for river bank protection prevented a pre-assembled pipe string from being pulled in. This was why pipe-by-pipe assembly (Fig. 6) with a fairly steep angle of entry at the assembly pit was adopted. A 12 m long inclined steel assembly ramp, which was enclosed in scaffolding and tarpaulins because of possible bad weather, was constructed for this purpose (Figs. 7 and 8). Following instruction by the pipe supplier’s applications engineering department (Fig. 9) and joint fitting of the traction head (Fig. 10), the actual pulling-in could begin (Fig. 11). The crew from the installing company soon got into a routine and the 486 m long pipeline was assembled and pulled in in just 34 hours, including the protection of the joints (60 hours had Fig. 6: Pipe-by-pipe assembly – the first DN 700 ductile iron pipe on the assembly ramp DUCTILE IRON PIPE SYSTEMS 61
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DUCTILE IRON PIPE SYSTEMS The Annua
Page 3 and 4:
Subjects and authors A DN 400 culve
Page 5 and 6:
Abstracts Ductile iron pipe systems
Page 7 and 8:
Germany’s biggest HDD project, us
Page 9 and 10: Fig. 1 Ductile iron pipes do not re
Page 11 and 12: Fig. 3 A DN 125 push-in joint being
Page 13 and 14: DN 500 culvert pipeline for sewage
Page 15 and 16: Fig. 3: Driving the sheet piling Fi
Page 17 and 18: Fig. 10: The traction head 3.3 Pull
Page 19 and 20: DN 700 pipeline for uncontaminated
Page 21 and 22: 4 Advantages of ductile iron as a p
Page 23 and 24: Immediately behind the socket, the
Page 25 and 26: GP 1 0.60 m GP 2 1.00 m GP 3 3.00 m
Page 27 and 28: References [1] EN 598 Ductile iron
Page 29 and 30: Fig. 1: Settling chamber outlet Sof
Page 31 and 32: Fig. 2: Double-socket tee with 45°
Page 33 and 34: The new EN 545 - Impact on practica
Page 35 and 36: The value of K can be freely select
Page 37 and 38: 4.2 Marking Quotation from EN 545:2
Page 39 and 40: Table 1: List of the four pressure
Page 41 and 42: To ensure that the pipeline remains
Page 43 and 44: Fig. 1 Diagrammatic representation
Page 45 and 46: A DN 400 culvert pipeline Culvert p
Page 47 and 48: Fig. 5: A culvert pipeline combinat
Page 49 and 50: Fig. 2: Removing the soil from an i
Page 51 and 52: DN 500 press-pull technique World p
Page 53 and 54: 3 The machinery and pipes As the in
Page 55 and 56: 4.2 Inspection of the old pipeline
Page 57 and 58: 4.6 Connecting together of the sect
Page 59: The horizontal direction drilling t
Page 63 and 64: een planned). All in all, an averag
Page 65 and 66: A DN 500 penstock pipeline A DN 500
Page 67 and 68: 4 The installation work For the qui
Page 69 and 70: DN 80 to DN 250 snow-making systems
Page 71 and 72: In their fully developed form, the
Page 73 and 74: Driven ductile iron piles 25 years
Page 75 and 76: ecomes very big and the advantages
Page 77 and 78: Fig. 7: The driven ductile iron pil
Page 79 and 80: Imprint Picture credits: Except whe
Page 81 and 82: A note from the Editor includes a s
Page 83 and 84: Notes DUCTILE IRON PIPE SYSTEMS 83
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