TY - CONF A1 - Auersch, Lutz ED - Vogiatzis, Konstantinos T1 - Modes and waves of coupled roof or floor structures in historical and modern buildings N2 - Long wooden floor beams above a ball room in an old historical palace have been analysed experimentally. The eleven beams are weakly coupled by three layers of floor boards. It has been investigated if the state (the stiffness) of the wooden beams can be determined by vibration measurements of global or preferably local modes. Hammer, heel-drop and ambient excitations have been used. The vibration modes of the structure show dominating local deformations if an impact excitation is applied. This is understood as the positive superposition of several modes which yield the maximum at the excitation point but a cancellation at more distant points. Natural modes have been estimated from these vibration modes by standard and special methods which were necessary for the high damping of the wooden floor. It has been found that all floor beams contribute to each natural mode even for a weak coupling of the beams. In addition to the modal discussion, the impact tests have also been analysed for the wave propagation and amplitude attenuation with distance. The coupling of floor beams has been studied theoretically by an analytic multiple-beam model where the coupling by translational or rotational springs and by a common support motion has been assumed. T2 - 23. International Congress on Sound and Vibration CY - Athen, Greece DA - 10.07.2016 KW - modal analysis KW - floor vibration KW - wave analysis PY - 2016 SN - 978-960-99226-2-3 SN - 2329-3675 SP - Paper 318, 1 EP - 8 AN - OPUS4-37090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -