UC San Diego

The floating modular hybrid pier (MHP) is a multi-level reinforced concrete structure that was developed as an alternative to traditional fixed pile-supported pier structures. A test structure was constructed to investigate the actual performance of the structure. To maintain its position in the bay, four Trellex MV1000x900B rubber fenders are mounted to the structure and face the sides of a mooring shaft. In addition to resisting the typical wind, wave, and tidal forces, they must be able to withstand ship berthing and seismic activity. In order to determine the level of performance available in this installation, the fenders were subjected to a series of long term tests, where creep behavior was studied. A series of short term tests were also developed to explore the temporary, high load behavior of the fender system. Since the reaction capacity and stiffness are rate dependent, two hydraulic actuators were used to load the fenders at varying rates for several cycles, which also allowed for a study of fender interaction behavior and friction between the fender and mooring shaft. Analysis of the test data has shown that the measured fender axial load-deformation relationship is typically similar to the manufacturer's data, with strength degradation at high displacement cyclic loading. Axial reaction capacity was also reduced during bi-axial testing due to the presence of lateral load. These studies revealed that the access ramp exhibits a high level of friction that significantly affects fender behavior for the test structure. Lower friction between the fenders and primary mooring shaft was found once sliding was initiated