Strong Motion Instrumentation for Structures of Civil Engineering and Economical Aspects of Planning of Territory of Big Cities

A number of strong earthquakes have taken place in last several years, and they were characterized by suddenly high peak values of accelerations (0.4–2.0 g). The existing position of structural engineers and scientists at the usage of so-called design accelerations is based on rather formal connection between acceleration and seismic intensity. So, according to Mercalli seismic scale (MMI), the design acceleration, which corresponds to earthquake intensity 9 degrees, has changed 5 times (from 0.1 to 0.5g) over the last 40 years. From the other side during high accelerations (2.0g, Nortridge, 1995 etc.) the intensity has reached even above-mentioned intensity of 9. At the same time a buildings designed at the intensity of 7 (e.g. 0.1g), very often can endure the seismic intensity of 9 degrees (0.4g, Sakhalin, 1995).The existing factors of seismic hazard are correlated badly with instrumental characteristics of earthquakes. All above-mentioned sets the problem for selection of parameter. which is directly connected with destructive seismic effect.Based at this and other views, the paper shows necessity of such type of equipment (strong motion instrumentation) which will give opportunity to test the reaction of buildings at seismic effect accurately, based on direct energy parameters or more closely on parameter which characterizes seismic effect (acceleration, velocity etc.),In the regions with low seismic intensity (Georgia), which means the country where the return period of strong earthquakes is rather long, it should be used the equipment (strong motion instrumentation) which would have widen working characteristics, in order to accept the weak signals.The paper contains economical aspects of planning of urban areas, based on hazard mitigation and vulnerability of buildings and structures in the case of their provision by corresponding strong motion instrumentation. The following part contains considerations about the creation of monitoring instrumental systems in buildings and at major structures of urban areas of Georgia.