Stainless steel circular tubular stub columns infilled with seawater sea-sand concrete: Experiments and design

Due to the acute shortage of fresh water and river sand in many places, especially remote islands, and the large carbon footprint of cement manufacturing, which has been causing global warming, it has been advocated in recent years to reduce fresh water, river sand and cement consumptions. Herein, it is proposed to infill seawater sea-sand concrete (SWSSC) into stainless steel tubes to form concrete-filled steel tubes, which should have the advantages of reduced fresh water, river sand and cement consumptions. A series of austenitic stainless steel circular tubular stub columns infilled with SWSSC were tested. The test results revealed that the use of SWSSC in place of conventional concrete in stainless steel tubes has little effect on the structural behaviour. A new design equation for stainless steel tubes infilled with different types of concrete, including SWSSC were proposed, which provided more accurate strength predictions than the existing design equations.