Development of Block-embedded Double-box type Caisson

The 5th District Port Construction Bureau, Ministy of Transport has been developing Block-embedded Double-box type Caisson adapted for the deep-sea (-40m) and the large waves (Hmax=16m) at the baymouth of Shimoda Port.As compared with the caisson covered with wave dissipating blocks in the deep-sea, this caisson saves many blocks, but it has the similar characteristics of wave left-lettlection and transmission.However, in order to keep the stability of embedded blocks, it is necessary to make the upper blocks of heavy concrete. Besides, the stress caused by highest wave is so large in some members of the caisson that it is necessary to use steel-concrete composite hybrid members.