Concrete weighting services
Concrete weighting services
Keywords Pipeline Induction Heat, Van Oord, Concrete
Pipeline Induction Heat Limited (PIH) have been awarded a subcontract by Van Oord ACZ, to apply a thick concrete jacket to the East of Scotland Water "Fillyside Storm Water Outfall Line", being fabricated at the dry docks in Leith, near Edinburgh.
The project represents a massive undertaking – 2,150mm/84.65 inch diameter steel pipes (19mm WT) are being supplied in 14-metre pipelengths and welded into eight "strings" with flanged ends. (Four strings will later be bolted together offshore, to create the "twin" 560-metre storm water outfall lines.)
PIH were selected to install a thick concrete jacket, that meets the following stringent project requirements:
All concrete placement to be performed "in situ" (within the dry dock) after welding-up of the strings (by Van Oord) into 140-metre lengths.
In places only 1-metre access distance exists between the individual pipe strings, within the dry dock.
Moulds must be capable of placement on/off the 85-inch pipe in this confined space, without fouling the concrete or damaging the gibe.
The large pipe diameter and comparatively thin pipe wall require that pipe handling must be minimised to prevent problems of ovality.
The concrete jacket was designed with an octagonal shape, eccentrically placed around the pipe, so as to provide negative buoyancy below the centreline.
This "bottom heavy" design will allow the pipe to fit snugly into a fairly narrow and shallow trench, while further preventing the pipe from twisting during and after installation (when it will be "exposed" to weathering elements at low tide).
Furthermore, the octagon shape (with vertical sides) negates any requirement to "rock-dump" over the pipe, thus significantly reducing installation costs.
The scale and location of the works presented PIH with a number of unique challenges, necessitating an innovative approach. Double-hinged vibrating "forms"(moulds) were developed for safe use within the enclosed dry dock environment.
"Health and safety" considerations are of paramount importance when working on such large pipes in confined spaces and PIH "work procedures"emphasise safe practice in all its operations.
Since the pipes are located deep within the dry dock, concrete delivery trucks cannot physically move alongside the pipe strings (as would normally be the case). Therefore, the moulds are being "fed" via concrete pumps and 22-metre length concrete booms.
The statistics of the job are impressive:
PIH are coating 30.5 linear metres of pipe every 12-hour shift.
Each 14-metre pipe weighs 69.48 tonnes (hence 694.8 tonnes per 140-metre length pipe string) following concrete coating.
During each 12-hour shift, PIH are casting approximately 132 tonnes of concrete.
Phil Bond, managing director of PIH, commented, "The project represents the first of its kind in the UK, and exemplifies PIH's commitment to providing innovative solutions to its worldwide customer base".
In related news, PIH Concrete Weighting Services has recently purchased two novel concrete coating machines, to further increase PIH's capacity to concrete weight all diameters of pipe on-site.
Further details are available from Pipeline Induction Heat Ltd (PIH). Tel : +44 (0) 1282 415323; Fax: + 44 (0) 1282 415326; E-mail: sales@pih.co.uk; Web site: www.pih.co.uk
