The feature article of a recent issue of the Structure Magazine titled
“Reclaiming the Waterfront”
was about the City of Vancouver, Washington’s new development along the Columbia River with the Grant Street Pier as its centerpiece. The focal point for this development is a concrete cantilever pier with an iconic and attractive form. The pier’s triangular, post-tensioned concrete deck overhangs the water by 90 feet and provides an expansive view of the river. A cable system and 80-foot-tall mast support the deck.
Two 11,000 lb tuned damping systems, designed and fabricated by DEICON, were installed in cavities within the concrete deck, close to the tip of the pier. The units were tuned to the natural frequency of the first mode (flapping mode) of vibration of the pier, measured when the construction was nearly complete.
Comparison of the vibration measurements conducted ‘before’ (the installation) and ‘after’ (the installation) of tuned damping systems revealed that the tuned mass dampers abated the vibration of the pier, significantly.