Structural behaviour and design of grouted connections cast with neat seawater mixed OPC

Seawater mixed neat ordinary Portland cement (OPC) has been used to connect tubular members of offshore structures since the 1940s in the Oil and Gas industry. More recently seawater mixed neat OPC has been used to connect the foundation piles of offshore wind turbine jacket structures, some of these structures are now since over 10 years in operation. The design of these connections was carried out mostly using design guidance stipulated in ISO 19902 or DNVGL Certification Guidelines. Despite the vast amount of documented background data substantiating these codes, it was to date not possible to readily carry out or certify design in accordance with the Eurocode design family, although constituent materials OPC CEM I and seawater as a mixing water are defined in EN 206 and EN 1008. The use of neat seawater cement grout, i.e. without any aggregates, is not covered in EN 1992 as a primary load carrying material. The aim of this work is to give comprehensive guidance for a Eurocode compliant design of concentric subsea connections grouted with seawater mixed neat OPC and subject to static and cyclical axial load with coexisting bending.