The Continued Functionality Standard is applied together with
ASCE 7-16, and the REDi Resilience-based Earthquake Design Initiative.
American Society of
1.3.3 Functionality. Structural systems and members and connections thereof assigned to Risk Category IV shall be designed with reasonable probability to have adequate structural strength and stiffness to limit deflections, lateral drift, or other deformations such that their behavior would not prevent function of the facility immediately following any of the design level environmental hazard events specified in this Standard.
Qualified Manufacturers and Code Compliant Seismic Isolation
Building codes allow structural members to be damaged during earthquakes, and some collapses of newly built structures are expected to occur. Expert seismic isolation engineering, quality manufactured bearings, and bearing performance criteria more stringent than code compliance, can effectively avoid damage to all structure members, which is the ultimate goal of seismic isolation technology.
Seismically isolated structures that are well designed and built minimize economic losses caused by earthquake shaking, and also reduce construction costs. Unqualified bearing manufacturers, or seismic isolation bearings that satisfy only the minimum building code requirements, can cause major structural damage and collapse. Since 1987, important applications of seismic isolation have selected manufacturers that have qualified their bearings through rigorous testing and successful in-service performance. Achieving reliable damage protection requires expert seismic isolation engineering, quality manufactured bearings, and specifying seismic performance more stringent than minimum code compliance.
Bearings made by unqualified fabricators without proven industry standards are extremely dangerous. In 1999, the newly constructed Trans-European Motorway in Turkey that had been seismically isolated came close to complete collapse due to poor seismic isolation engineering and products. Over 1000 seismic isolation bearings and dampers failed, and structure repair costs were over US $100 Million. Public safety requires that construction plans specify qualified bearing manufacturers that have proven the adequacy of their products, materials and manufacturing standards.