Displacement-based conception of moment-resisting frames that house essential facilities

The pertinence of using an importance factor to promote an adequate structural and non-structural performance of essential facilities is studied. Although an importance factor of 1.5 may promote adequate performance of essential facilities built in firm soil; the value of this factor for structures built in soft soil exhibits significant dependence with respect to the dynamic characteristics of the structural system. Because of this, the current use given to the importance factor may result in conservative or unsafe design of essential facilities built in soft soils. One way to improve the seismic design of essential facilities is to formulate displacement-based approaches. Within this context, a displacement-based methodology should aim at controlling simultaneously the level of structural and non-structural damage by limiting the plastic rotation and inter-story drift demands in the structural system of the essential facility.

► The use of an importance factor aims to promote an adequate performance of essential facilities.
► The importance factor may work in the seismic design of essential facilities built in firm soil.
► The importance factor may result in unsafe design of essential facilities built in soft soils.
► A displacement-based methodology aimed at the design of essential facilities is formulated.
► The proposed methodology yields adequate level of design of essential facilities.