Collapse modes of structures under strong motions of earthquake

Under strong motion earthquakes, structures receive various types of damage. The most fatal damage is the loss of lateral strengths of a structure. The loss of lateral resistance causes a total collapse of the structure due to the P-d effect associated with the lateral displacements and the gravity loading. To eliminate such a collapse mode, to introduce into the ordinary stiff structure a flexible element which remains elastic is very effective. The flexible-stiff mixed structure can behave preferably in many aspects under strong earthquakes