Assessment of the 1991 NEHRP Provisions for Nonstructural Components and Recommended Revisions

Keywords: National Earthquake Hazards Reduction Program, NEHRP Provisions, 1991 Edition, Architectural Elements, Anchorage Detailing, Nonstructural Elements, Earthquake Resistant Design, Mechanical Components, Structural Yielding, Design Coefficients, Design Recommendations, Electrical Components, and Structural Period.

Abstract: This report represents part of the 1994 effort to update the provisions of the 1991 National Earthquake Hazards Reduction Program (NEHRP). The 1991 seismic design formulas for nonstructural components are critically reviewed and improvements are recommended based on analyses and experiment. The improvements preserve the equivalent lateral force format for design applicability and correct some of the deficiencies. Three recommendations are proposed and the maximum and minimum design forces in the three recommendations are compared with those produced by the 1991 NEHRP provisions, the 1991 Uniform Building Code (UBC), and the 1985 Tri-Services Code. Case studies of a parapet, a storage rack, and equipment attached to a reinforced concrete shear wall are provided to show the relative conservatism involved in different codes and the importance of the factors ignored in the current provisions.