Large machines operations cause vibration to its supporting floor as well as its sheltering structures. Vibration is measured and evaluation is made accordingly. Pictures below show a case that once machines are functioning, a strong vibration is observed in its sheltering structure and a large deformation is visualized in long-slender steel columns. Reason found to be the accidentally matching between machine vibration frequency and 1st natural frequency of the columns. Resonance therefore occurs. Solutions later on are given and problems are solved successfully.
Vibration measurement is conducted through accelerometer and dynamic data acquisition system. Data is then analyzed to determine machine vibration frequency and column displacement is also interpreted. The vibration measurement was done at various locations: machine platform, column at base, column at machine level and column at top level, the results shown that, even the machine vibration is just 0.035g, but column vibration reaches 0.1755g, this phenomena causes the column and siding walls to shake horizontally, large deformation of column in out of plane was interpreted from acceleration data to be 0.4 cm, exactly same as visual observation. Slenderness ratio of column in out of plane direction was greater than recommended value given by codes of practice for steel design. SOLUTIONS are then GIVEN and PROBLEMS are SOLVED.