Analysis and retrofitting of fixed steel platforms under low seismic loads

Abstract

The low seismic load effects on offshore platforms designed without considering the earthquake load with different water depths and brace configurations was investigated in Northern Borneo.In order to propose a new strengthening scheme with high strength CFRP for platforms that cannot resist the extreme level of earthquake load, long circular steel braces (88.9mm X 4mm) are retrofitted with CFRP sheets in various configurations and tested to study the effects of CFRP on overall buckling behavior. The results show that CFRP effectively increases the axial strength and stiffness of steel braces. Finally, two retrofitting methods, one with high strength grout and the other with CFRP are used to enhance the performance of the offshore platforms that could not resist the extreme level of earthquake load at the chosen site under the combination of wave and earthquake loads.