Damage states of an underground tunnel structure need to be defined in the estimation of its seismic fragility. They are identified in this paper by applying pushover analyses of an typical tunnel structure. Latin Hypercube sampling (LHS) technique is used to explicitly consider uncertainties in the associated design variables.

A RSM-based reliability analysis approach is applied to evaluate the safety of floating structures considering uncertainties associated with various design variables. Uncertainties in both load and resistance related variables are explicitly considered in the analysis. It is expected to be practically applied in the reliability-based design of real structures including floating structures.

This paper deals with the response analysis of a floating building structure subject to both wind and wave loads. The hydrodynamic analysis is performed with sets of wind and wave loads selected from the 100-year return period concept to assess the effect of extreme ocean environmental loads on a floating building. From hydrodynamic analysis in time-domain analysis, it is shown that the responses obtained from the analysis in consideration of both wind and wave loads are far greater than those of wave load only.

In this paper a computationally efficient methodology to establish the seismic fragility curve for underground tunnel structures is developed by integrating the response acceleration method and the maximum likelihood approach with a large set of artificial ground motion time-histories. It is elaborated with an illustrative numerical example.