LAX Theme Building

nees@UCLA recently assisted in the voluntary seismic retrofit project for the iconic Theme Building at Los Angeles International Airport. In October 2007, the nees@UCLA team was responsible for experimental modal analysis on this very unique historic structure to help understand its dynamic behavior as it responds to vibration, wind and earthquake loading. Led by Dr. Robert Nigbor and Prof. John Wallace, nees@UCLA measured the mode shapes, frequencies and damping ratios under ambient and forced vibration.

The Los Angeles World Airports (LAWA) design team developed computer models to be used in engineering analysis and retrofit design to extend the life of the building. Due to the unusual architectural configuration and uncertainties in the material properties, these computer models were validated using actual measurements of the structure's dynamic properties. Experimental modal analysis was repeated in April, 2010 after construction to verify performance. Of particular interest was the performance of the unique 1.2 million pound tuned-mass damper ("TMD") atop the central building core. UCLA engineers devised a way to push this large mass sideways and release it, allowing direct measurement of its as-built frequency and damping. After these tests, a permanent earthquake monitoring instrumentation was installed to capture response to future earthquakes and to act as a testbed for advanced structural monitoring research.


LAX Theme Building


S. Keowen working on the shaker