INSTRUMENTS FOR DYNAMIC MEASUREMENTS

Abstract

In the rapidly developing construction activity of various types of projects the dynamic measurements have assumed a definite important role. The measurements may be required in the laboratory or f Leld studies. In the laboratory they are useful to arrive a basis for design and to predict the behaviour of certain important type of structures and machine elements under dynamic conditions. In the field the measurements are required to provide a check on the theoretical analysis and laboratory studies. The vibrations may be the result of a blast, eartquake, operation of machinery or fast moving traffic etc. To measure the vibration characteristics three types of pick-ups, viz., displacement pick-ups , velocity pickups and acceleration pick ups are commonly used. Also to enable precise design of structures in seismic zones study of behaviour of struc-tures under dynamic conditions and frequency and intensity of earthquakes is necessary. In such studies experimental analysis would be more helpful than the theoretical one fora realistic approach. The structural response recorders and strong motion accelerographs etc. are useful for collecting the necessary basic data in this regard. Further, in the design of foundations of structures subjected to dynamic forces the knowledge of behaviour of soils under dynamic conditions is also a must. For this the test?ican be carried out with shear box and oscillatory shear box etc. Thus the instruments for dynamic measurements are indispensable in all these studies.