The future energy demand necessitates the exploration of all potential energy sources both onshore and offshore. Global trend has shifted towards offshore energy, which can be obtained from either carbon intensive or renewable options, hence requiring structures such as rigs, platforms, and monopiles. Most of these structures adopt easily installable construction techniques, where lower foundation need to be connected with the super structure by mean of grouted composite joints. Generally, these composite connections have exterior sleeve, interior pile and infill grout. Being located in remote offshore conditions, connections can experience considerable adverse loading during their lifetimes. Degradations were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites may often be proven difficult, which eventually leads to reduced capacity of connections in the long run. Thus, repair and rehabilitation of such connections should be planned ahead to minimize operational delays and costs in the future. This study aims at characterizing the nature of crack generation in grouted connections and thereby identifying the potential of repair using suitable repair material. Scaled grouted joints were manufactured using a novel mold, and connections were loaded under static load to visualize the main failure pattern. The failure mechanism and loading capacity are found compatible to previous results from earlier literature. Grouted connection was then repaired using cementitious injectable grout. The effectiveness of the repair system is also discussed.
Current advancement in the modern world is dependent on energy. About 30% growth is expected in energy demand worldwide by the year 2040 (International Energy Agency 2014). Although, oil and gas (O&G) sector may well dominate the global primary energy supply for the rest of this century, energy security issues are directing countries towards renewable energy choices, which can reduce their dependency on fossil fuels as well as achieving sustainable energy future (Larsen & Petersen 2010). Hence, a future of sustainable energy demands substitution of fossil fuels by renewable energy sources around the world. The contribution of renewable energy sources in primary energy use, suggested by the New Policies Scenario, is raised to 18% in 2035 compared to 13% in 2011, where wind energy is expected to provide major share, limiting the rapid growth of traditional fossil fuels (International Energy Agency 2013). In fact, investments towards annual wind energy in 27 European Union member states (EU-27) will reach almost €20 billion with 60% towards offshore productions by 2030 (Krohn et al. 2009). At the end of 2015, Europes collective installed capacity reached 11027 MW across a total of 3230 wind turbines (Ho et al. 2016). Ho et al. also stated that there were 84 offshore wind farms, including sites under construction, in 11 European countries. Therefore, growing energy demand and advancement of technology lead to explore both onshore and offshore locations using wind structures, which are susceptible to adverse loading conditions and costly maintenance.