Non-destructive modal parameter identification of historical timber bridges using ambient vibration tests after restoration

Abstract

Historical structures are important cultural relics which illustrate the progress of engineering development. They are a valuable source of information on construction techniques and materials selection over the centuries. However, many factors, including environmental conditions and natural disasters, contribute to damage and destruction of historical structures. Today, the aim of restoration is to carry out necessary works with care and sensitivity while ensuring historical buildings are restored as near as possible to their original structural strength. However, the extent of the contribution of the restoration to the structure and the determination of the restoration success is carried out by various non-destructive experimental studies. This aim of this paper was to obtain structural modal parameters for the historical timber Buzlupınar Bridge using non-destructive ambient vibration tests after restoration. From calculations of natural frequencies and mode shapes, it can be seen that the six natural frequencies obtained are between 2.0 and 20.0 Hz. To minimize the 34.55% differences in experimental and numerical natural frequencies, a FE model of the timber bridge was updated using manual model updating procedures. The maximum differences were reduced to below 1% except for the fourth mode.