Device for protecting a structure against the effects of high horizontal dynamic stresses

Claim 1

A construction protected against the effects of high horizontal dynamic stresses and vibrations especially of seismic origin, said construct-ion resting on foundations by a plurality of seating block means each compri-sing in combination a) friction means for permitting relative horizontal dis-placement of the construction with respect to the foundations, said friction means absorbing at least part of the energy of said horizontal dynamic stres-ses, said friction means having two horizontal friction surfaces in contact with each other, said friction surfaces having a predetermined coefficient of static and dynamic friction comprised between a minimum value which is com-patible with the permissible displacements of the construction as a function of the structural connections of the construction and a maximum value which is compatible with the threshold value of inherent resistance of said con-struction, said minimum and maximum values being chosen within the range be-tween 0.08 and 0.5, the nature, the surface treatment and the profile of said friction surfaces being such that said coefficient of friction is stable in time and substantially constant and lies in said range in respect of maximum rates of displacement within the range of 0.20 to m/sec approximately and in respect of bearing pressures within the range of 290 to 2900 p.s.i. approxi-mately; and b) elastomer blocks supporting the weight of the construction and dimensioned such that the vibration of the different points of the construct-ion is in phase and is maintained below 4 Hz, thereby to prevent resonance of the construction with the frequency of the seismic vibrations.