Identification of Rational Functions using two-degree-of-freedom model by forced vibration method

An enhanced forced vibration rig for wind tunnel testing of bridge deck section models in arbitrary motion

“…Several experimental setups capable of forcing the section model in horizontal, vertical and pitching motions have been presented more recently (Diana et al, 2004;Han et al, 2014;Lee and Kwon, 2009;Neuhaus et al, 2009;Sarkar, et al, 2004). It is interesting that experimental setup developed at Iowa State University (Cao and Sarkar, 2012;Sarkar et al, 2007Sarkar et al, , 2004) is able to perform both free and forced vibration test. It is achieved by a system of springs and pneumatic bushings that glide along polished steel shafts making the friction very low.…”

“…Cao and Sarkar, 2012;Chen et al, 2005;Diana et al, 2004Diana et al, , 2010Diana et al, , 2015Falco et al, 1992;Han et al, 2014;Lee and Kwon, 2009;Li, 1995;Matsumoto et al, 1993;Matsumoto, 1996;Neuhaus et al, 2009;Sarkar et al, 2009). Forced vibration tests considering vertical and pitching motions are now routinely conducted when designing bridges, occasionally allowing for coupling between the two motions (Cao and Sarkar, 2012;Diana et al, 2004;Falco et al, 1992;Han et al, 2014). Several experimental setups capable of forcing the section model in horizontal, vertical and pitching motions have been presented more recently (Diana et al, 2004;Han et al, 2014;Lee and Kwon, 2009;Neuhaus et al, 2009;Sarkar, et al, 2004).…”

“…Significant progress has been made since Ukeguchi et al, (1966) presented the first experimental results for bridge decks in 1966, and an impressive amount of forced vibration rigs used in research can be found in the literature (e.g. Cao and Sarkar, 2012;Chen et al, 2005;Diana et al, 2004Diana et al, , 2010Diana et al, , 2015Falco et al, 1992;Han et al, 2014;Lee and Kwon, 2009;Li, 1995;Matsumoto et al, 1993;Matsumoto, 1996;Neuhaus et al, 2009;Sarkar et al, 2009). Forced vibration tests considering vertical and pitching motions are now routinely conducted when designing bridges, occasionally allowing for coupling between the two motions (Cao and Sarkar, 2012;Diana et al, 2004;Falco et al, 1992;Han et al, 2014).…”

“…Despite the considerable progress made in the modeling of self-excited forces using rational or indicial functions (e.g. Cao and Sarkar, 2012;Caracoglia and Jones, 2003;Chowdhury and Sarkar, 2005;Costa, 2007;Costa and Borri, 2006;Salvatori and Borri, 2007;Zhang et al, 2011;Zhang and Chen, 2010;Øiseth et al, 2011, aerodynamic derivatives, as introduced in bridge engineering by Scanlan and Tomko (1971), remains the most common output from wind tunnel tests of bridges. The aerodynamic derivatives for a bridge cross-section can be determined by either forced or free vibration tests.…”

“…Thus, free vibration tests are considered to provide more realistic in-wind motion of the bridge deck and are easier to perform and less expensive; however, it is far more challenging to identify the aerodynamic derivatives from free vibration data; see (Bogunović Jakobsen and Hjorth-Hansen, 1995;Brownjohn and Jakobsen, 2001;Chowdhury and Sarkar, 2003;Sarkar et al, 1994;Scanlan, 1978) for an overview of the methodology available. The forced vibration technique provides higher data reliability (Diana et al, 2015) and is more suitable for higher velocities, larger motion amplitudes and higher turbulence intensities (Cao and Sarkar, 2012;Sarkar et al, 2009). However, the ability to consider a realistic bridge deck motion might be important for some cross sections.…”