An Investigation into Recommendations of NZSEE for Seismic Assessment of Steel Moment Resisting Frames

Abstract

The major guidance documents for seismic assessment of existing buildings are ASCE 41-06 in US, Eurocode 8 Part 3 in Europe and NZSEE recommendations in New Zealand. All of these guidelines have proposed using nonlinear static analysis as a tool for seismic assessment of buildings. In New Zealand recommendations there is a parameter %NBS which means percentage of new building standard, the building with %NBS=100 is a building that satisfies standards of a new building. NZSEE recommendations have proposed force based, displacement based and consolidated force / displacement based methods for seismic assessment of existing buildings. Consolidated force / displacement based method is a combination of force based and displacement based methods. Displacement based method has a direct emphasis on estimating the ultimate displacement capacity of the structure and utilizes displacement spectra which can represent the characteristics of earthquakes. In this paper 5 and 10 story steel moment resisting frames are designed with %NBS approximately equal to 100 calculated via displacement based method. In this method the nonlinear static analysis is used for estimating strength and deformation capacity of steel moment resisting frames then nonlinear dynamic analysis procedure is used to assess the seismic performance of these structures according to ASCE 41-06.