Osamu Ishizaka / Planning and Promotion Section, MAEDAKOSEN Co., Ltd.
Shinji Sassa / Port and Airport Research Institute, National Institute of Maritime, Port and Aviation Technology
A new wave reduction method, called the Net Buffer Method, has been developed by the authors
to reduce caisson joint waves for suppressing internal erosion and collapse behind seawalls and
quaywalls. This new method, in which a net fiber material is installed within the joints, is capable
of reducing caisson joint waves by more than 80% in terms of the maximum and average wave
pressures. This study investigated the applicability of this method as a preventive maintenance and
recurrence prevention measure against coastal internal erosion and collapse based on field
observations. The results of analysis of the measured caisson joint wave pressures during the
passage of three typhoons and a seven-year follow-up survey show the effectiveness of this method
as a preventive maintenance and in preventing re-collapse under severer wave conditions than
those that led to collapse in the past.