The Technological Research Association of Mega-Float in Japan was organized in 1995 to start a R & D project of Mega-Float. In the first phase of the project from 1995 through 1997, a 300m-class pontoon-type model was constructed in Tokyo Bay and field measurements were carried out on responses of the model and environmental conditions. In the second phase of the project from 1998 through 2001, a 1000m-class pontoon-type model was constructed in the vicinity of the phase I site and landing and take-off tests were conducted to verify the applicability of the mega-float as an airport. Also done were field measurements on responses of the elastic deflection and the mooring system to validate the simulation program developed in the project. The non-linear mooring simulation program calculates the responses of motions and reaction forces of the mooring system in time domain, using the hydrodynamic forces calculated by another developed code. In this paper, mooring simulations for the 1000m phase II model are conducted. Calculated results of the horizontal motions of the megafloat and reaction forces of the mooring system are confirmed to have good agreement with the measured results. It is verified that the mooring simulation program of the mega-float is a useful tool for design of the mooring system of the mega-float.
A nonlinear mooring analysis system for designing mooring system of the mega-float has been developed in the mega-float research project. The mooring analysis system consists of a hydrodynamic analysis code in frequency domain and a nonlinear motion analysis code in time domain. The present paper shows usefulness of the mooring analysis system in comparison of computed and measured results on the horizontal motions and the mooring forces of a 1,000m long mega-float phase-II model, moored off Yokosuka from September of 1999 to December of 2000.