The Client's Angoflex facility needed a significant upgrade to support the manufacture of longer and larger umbilicals. This required upgrading the existing factory to support two cranes each twice the capacity of the existing crane, the extension of the foundation for an enlarged planetary strander machine and the construction of foundations for two basket spooling carrousels, each with a total load of nearly 2,700 tonnes. The design challenges were to avoid major modifications to the existing steelwork and existing building foundations, and to ensure that specified differential and absolute settlement criteria for the carrousels would be met over their design life.
Royal HaskoningDHV undertook significant research of the applied loadings to the building and the ground, together with a detailed review to develop a design philosophy that would ensure compliance with the Client’s stated aims. There were two key elements to achieving those goals. Firstly was the geotechnical work that identified surcharging as the most appropriate method of improving the ground for the carrousel foundations. Secondly was the application of realistic loads and load combinations and the specification of a spreader beam for the cranes. This was all achieved in close co-operation with the Client’s project management team on site.
The comparison between the predicted and recorded settlements for the nine months of the surcharging process was insignificant. This gave the Client’s confidence in a novel solution to a significant issue, because the comparison was consistent at thirteen locations across the site and for every week of the nine months over which records were kept. We were equally diligent and successful with the other elements of the project so that our involvement with this site continues.