Presentation on theme: "Forced vibration modal testing of ‘International Bridge’ at Wayne, New Jersey, 21-23 July 2010 Prof. James Brownjohn Dr Ki-Young Koo Dr Chris Middleton."— Presentation transcript:
Forced vibration modal testing of ‘International Bridge’ at Wayne, New Jersey, 21-23 July 2010 Prof. James Brownjohn Dr Ki-Young Koo Dr Chris Middleton The University of Sheffield Department of Civil and Structural Engineering Vibration Engineering Section
Lessons Expected to be able to do two spans: took much longer to move between swipes! Could have done one span per night We could get good quality FRFs with light ‘automobile’ traffic OMAX proved very effective Walkway swipe was very valuable –dynamic link between spans, no evidence of amplitude dependence Orthotropic nature of deck revealed by set of swipes Movement at piers was surprising, shame we couldn’t study horizontal movement Step-sine testing was tedious and not good value Shaker testing did give OK FRFs
What we would do in future Think seriously about the logistics of moving accelerometers Probably foregoing the luxury of full realisation of mode shapes & use reduced cross-deck measurements Pay more attention to the bearings, which in any case are more accessible Estimate modal mass, frequency and damping from shaker chirp excitation Use either shaker shutdown or passage of heavy vehicle to obtain reliable frequency and damping estimates.