Alternative Foundation Methods for Upgradation of Oil Jetty

Abstract

Marine civil structures in the harbour are used to handle various types of cargoes. Liquid cargo terminal berth vessels are used for loading and unloading of petroleum, oil, lubricants and other liquid chemical products. These liquid cargoes move through pipelines. India is keen to explore the possibilities of increasing the capacity utilization of oil berths and to improve the existing liquid terminals to handle the ever-growing demand for POL and other liquid cargoes. The objective of the present study is to assess and suggest the most suitable among the proposed three alternative methods for upgrading the oil berth at Visakhapatnam Port Trust (VPT). The existing oil berths at VPT have a dredge level of −10 m, which were built using caissons more than 40 years back and will be dismantled after constructing new berths which will have dredge level of −16 m. The space available between the existing berths and current pipeline layout is limited and restricted posing a challenge for capacity augmentation. The alternative methods for substructure configuration are as follows (i) T-diaphragm wall + pile + anchor wall, (ii) T-diaphragm wall + pile + anchor wall + anchor rod and (iii) pile + rectangular diaphragm wall, respectively. The proposed structural configurations have been analysed to withstand the maximum forces acting on the berth. In addition, these three alternative foundation options once implemented will handle vessels up to 85,000 DWT (Panamax size). This techno-commercial exercise was carried out through STAAD Pro V8i software to analyse the structural integrity and foundation stability in collapse and service conditions for all three alternative methods. The comparison of results indicates that the first alternative has better structural stability and is also cost-effective.