FULL SCALE EVALUATION OF THE CORE TUBES GROUT INJECTION METHOD FOR LARGE DIAMETER HDPE OFFSHORE PIPELINES SINKING

April 25, 2022 by admin in Uncategorized

Mehdi Jalili, Maziar Neyshabouri, Ashkan Nasrollahi

# 2021 Amsterdam

Seawater intake/outfall systems in nine lines with 1400/2200 m length and large diameter polyethylene pipelines (O.D. 2700 mm dia.) had been designed and fabricated to supply 4,200,000 cubic meters per day seawater into a basin in northern coast of Persian Gulf, Bandar Abbas/IRAN. The usual sinking by additional concrete ballasts had been considered for installation of the pipelines in basic engineering phase. During the detailed installation engineering an alternative method considered which was grouting the core tubes in the pipe wall instead of the use of the concrete ballasts. This novel method evaluated by performing two bending tests on 30 m strings. Based on the tests results, grouting the core tubes has no significant effect on the initial deformation of the strings under pipe’s own weight in comparison to the situation of the Non-grouted pipes with concrete ballasts. Furthermore, it could be predicted that the grouting would have no significant effect on the pipe string’s stiffness in the sinking conditions that string will experience a great deformation. The bend radius ratio to the pipe diameter obtained 32 and 34 for the Grouted and Non-Grouted pipes, respectively, and no defect have been observed in both strings. Therefore, no difference would be observed regarding the bending behavior of the grouted pipes in comparison to the non-grouted pipes. The pipeline installation with using the grout injection in the pipes has been done successfully in the project and it could be recommended as the lessons learned for similar projects which PE pipes will be installed in shallow water conditions, considering advantages such as uniformly weighted pipe, no local loading exerted by ballasting weights, faster construction, and decrease the possibility of free spanning occurrence.

articles source :  https://www.pe100plus.com/PPCA/FULL-SCALE-EVALUATION-OF-THE-CORE-TUBES-GROUT-INJECTION-METHOD-FOR-LARGE-DIAMETER-HDPE-OFFSHORE-PIPELINES-SINKING-p1742.html