Some Thoughts on Permanent Risk in the Earthquake Engineering Context

摘要

The aim of this paper is to illustrate that the existing ideology of aseismic design cannot provide the reliable prognosis of the levels of damages to buildings in future. If the mankind does not realize the necessity to reduce the level of risk contained in the current ideology of aseismic design, the number of seismically instable buildings will increase even more in the (ⅩⅩⅠ) century. The only way of reducing the risk associated with the ideology of aseismic design appears to be the requirement for the undamaged structural behavior of building. The requirement for the undamaged structural behavior of building is something like a threshold (a level), the raising of which increases the reliability of constructions planned to be built in seismically active regions and, on the contrary, its lowering increases the uncertainties and makes the behavior unpredictable. The modern global tendencies of aseismic design are to lower this level as much as possible and to make the constructions cheaper. According to the opinion of the present writer though the level, on the contrary, should be raised, in order to keep off the chaos.