A prescriptive method for the design of new steel moment frame structures with supplemental damping

Abstract

This paper presents a prescriptive method for the design of new steel moment frame structures with supplemental damping using fluid viscous dampers. The prescriptive method uses Modal Response Spectrum Analysis (MRSA) instead of Nonlinear Response History Analysis (NLRHA) as the basis for evaluation. Additionally, the procedure decouples the design of the moment frame from the damper frame, reducing design iterations. This makes the use of FVDs in new buildings easier to evaluate at schematic level design and significantly reduces the effort for full design. The procedure produces a 25% viscous damping ratio at the Design Earthquake (10% probability of exceedance in 50 years) and requires the use of nonlinear dampers with a damping exponent, alpha of 0.4.

The design procedure has been developed and validated through the AC 494 and FEMA P-695 procedures and has been approved by the ICC Evaluation Services process. An overview of the procedure development and approval process will be provided, including a description of the evaluation archetype space, nonlinear modeling and collapse probability evaluation using incremental dynamic analysis. While the design procedure has been written in alignment with the United States’ ASCE 7-16 provisions, the ICC-ESR is applicable in both New Zealand and Australia. While presenting the prescriptive method design procedure, this paper presents appropriate parallels between the ASCE 7-16 code approach and the New Zealand Standard NZS 1170.5.2004.