Constantinou, Michael

Seismic Isolation Bounding Analysis: Property Modification Factor Approach of Asce 7-2016 and Asce 41-2017

Abstract eng:
The application of seismic isolation in the United States is regulated by Building Codes which invariably refer to Chapter 17 of ASCE 7 (the Standard) for the analysis and design requirements of new buildings and Chapter 14 of ASCE 41 for the retrofit of existing buildings. The Standard has evolved over the years to reflect the state of the art knowledge and practice in the field. The latest evolution, ASCE 7-2016, now includes a systematic procedure for establishing maximum and minimum probable values of bearing properties with due consideration for three categories of effects, namely: 1) aging effects and environmental conditions, 2) hysteretic heating and speed of loading effects, and 3) manufacturing variations. This paper provides guidance to practicing engineers on the basis and implementation of the Standard, with respect to the property modification (λ) factors. These factors are used to define the isolation system properties that are used in separate upper- and lower-bound analyses, where the governing case for each response parameter of interest is used for design. The determination of isolation system properties is illustrated for a lead-rubber and a concave sliding isolation systems. For each system, the following design scenarios were investigated: (a) assuming there is little qualification test data available and adopting default properties, and (b) using prototype test data of two bearings to calculate properties. Although these λ factors may be useful for similar systems, they are project-specific, manufacturer-specific and also dependent on the materials used, therefore cannot be merely adopted for other designs. The requirements of ASCE 7-2016 have been largely replicated in ASCE 41-2017, with the intent being identical, thus for simplicity only one Standard (ASCE 7) is mentioned in this paper. Nevertheless, ASCE 41-2017 contains differences and further improvements on the Standard based on the work of the authors. The second author was involved in the revision of ASCE 7 and the first author was involved in the alignment of ASCE 41 provisions.

Contributors:

Mcvitty, William

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.