Cemex West Sacramento Cement Import Terminal

The site's relatively low seismicity created an unusual condition where the vessel broadside berthing forces, rather than earthquake loads, threatened to drive up the pile count and overall project cost. The cement unloader added further complexity. Its multiple modes of vibration and large mass meant a standard structural analysis wouldn't accurately capture its effect on the wharf's seismic behavior.

Liftech designed the wharf so that half of the fenders were recessed and only half would load the wharf during a broadside berthing. This resulted in a dramatic reduction in the number of piles compared to the competing design-build team. This in turn reduced the wharf’s lateral stiffness, increasing its period of vibration, and reduced its earthquake loading. Liftech designed the entire wharf superstructure as a slab without crane girders, delivering further cost savings. To address the unloader's seismic influence, Liftech performed a novel dynamic analysis of the combined wharf and unloader structure to accurately design for the unloader forces and provide useful earthquake design guidance to the unloader manufacturer.