CHARACTERISTICS OF WAVE-INDUCED BENDING MOMENT AND SHEAR FORCE IN PONTOON-TYPE VLFSS

摘要

Recently very large floating structures (VLFSs) available for international airport have been developed in Japan. The national project of 'Mega-float' proved the feasibility and the large potential for utilizing ocean space. In the structural design, designers have to decide principal dimensions and scantlings of the structure considering a lot of constraints including safety constraints as well as functional ones. Wave loads acting on the VLFSs are mainly governed by elastic behavior of the structure unlike wave loads on ship structures. Therefore hydroelastic response analysis is needed for bending moment and shear force due to wave loads. In other words, different rigidity of the structure produces different stresses due to hydroelastic effect. In the initial design stage, structural optimization should be performed to decide the initial scantlings considering hydroelasticity. But hydroelastic analysis of VLFS is time-consuming procedure. Therefore simple formulas to predict those stress resultants are demanded. In the present study the characteristics of wave-induced bending moment and shear force that can produce bending stress and shear stress have been investigated for some design parameters by numerical simulation considering hydroelasticity. And some formulas for the wave-induced resultant stresses available for structural optimization are proposed.