A STUDY FOR WAVE RESPONSE OF HORIZONTAL-ARCH BRIDGES WITH SEMI-SUBMERSIBLE FLOATING FOUNDATIONS

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This research has studied "Horizontal-arch bridges with semi-submersible floating foundations, " which the floating pontoon foundations are replaced by the semi-submersible floating foundations. In this study, the attention has been paid on the wave response characteristics, and the effect of the foundation shapes are examined to improve the wave-resistant design.The diffraction and radiation wave forces have been calculated by using axi-symmetric Finite Element Program for each floating foundation. The program enploys infinite elements for satisfying radiation condition at infinity. The bridge structure is modeled as a elastic beam, and the whole structural system has been analyzed by NASTRAN,general purpose F.E.M.program. The fluid-elastic structure system has successfully been analyzed by the procedure.The effect of the floating foundations have been examined on the condition that the immersed displacement of the foundation has the constant value. Numerical examples have shown that the semi-submersible type floating bridge has an improved characteristics. Moreover, the floating bridge that the Osaka municipal office is now planning at Maishima-Yumeshima channel is studied, and the transient response analysis in the time-domain considering nonlinearity of the fender and the elastic deformation of the bridge system has also been made.