Reformulation and Evaluation of ASCE 43–05 Approximate Design Criteria for Rocking Systems

This work reformulates the approximate seismic design methodology for slender rocking structures in ASCE 43–05 within a mechanics-based framework. Using dimensional analysis, two theoretically consistent and equivalent approaches are developed: Spectrum-Based Iterative Design (SBID) and Spectrum-Based Direct Design (SBDD). Within SBID, the Stability Coefficient Spectrum (SCS) and Rocking Spectrum (RS) operate iteratively to satisfy target objectives, whereas the proposed Constant Rotation Spectrum (CRS) provides equivalent solutions directly and efficiently. Procedures are demonstrated for pulse-type excitations and recorded motions. Comparisons with nonlinear response-history analysis reveal conservative or unconservative predictions without consistent bias, emphasizing the need of engineering judgment.