for amplified viola and tape
The original Tacoma Narrows bridge opened for traffic on July 1, 1940 and collapsed in a spectacular manner into the Puget Sound on Nov. 7, 1940 just six short months after it had opened. Unbeknownst to the bridge's engineers, the thin roadway they designed acted like a giant airfoil and caused the bridge to oscillate up and down in the face of strong winds blowing in from the ocean. On the day of its collapse, a strong steady 40 mph crosswind forced the bridge into a new torsional mode of vibration of .2 Hz and the entire structure began to twist and buckle in addition to its more typical up and down oscillation. A famous film shot by Barney Elliot captures the last moments of this beautiful and graceful structure as it literally shook itself apart and collapsed into the deep waters below. The spectacular twisting and fracturing motion of the bridge's last gallop provides the inspiration for this composition. The main source for the work is a graceful, untempered pentatonic scale made from partials 17, 19, 23, 27 and 31 of the harmonic series (roughly C# D# F# A# B#) that is then "fractured" in various ways to create all the pitch material presented the work. In the first type of fracturing, "foreign tones" (actually partials 1, 3 and 5) are sequentially added to the pentatonic collection to build increasingly dissonant microtonal scales of 6, 7 and 8 tones. Each of these scales are introduced as rising step-wise motion that is then "twisted" using a multi layered change-ringing strategy to form each sections melodic activity. In another sort of fracturing, the tape sounds are generated by superimposing many copies of the fiddling music but slightly shifted and stretched in time by prime number ratios so that a non-periodic harmonic smearing takes place. Finally, the .2 Hz destructive mode that produced the fatal twisting vibration in the bridge provides the incessant, steady fiddling pulse that underlies the perpetuum mobile effect of the entire work.
Tacoma Narrows was composed in the Common Music software package with audio produced by Common Lisp Music, developed by William Schottstaedt at CCRMA, Stanford. The performance score was generated to Finale using the FOMUS music notation package developed by David Psenicka at University of Illinois. Tacoma Narrows was commissioned by, and is dedicated to, Melia Watras of the University of Washington. Funding support for commission and CD recording was granted by The University of Washington Royalty Research Fund. A recording of Tacoma Narrows appears on Melia Watras' latest CD released by Fleur de Son Classics, Ltd.