The Blind Side: Using ‘Canned’ Loading Protocols in Seismic Testing

Published: June 17, 2019

Author(s)

Matthew S. Speicher, Bruce F. Maison

Abstract

The seismic behavior of a building component (e.g., shear wall) is a fundamental attribute engineers need to assess the earthquake performance of a building. It is no surprise that component behavior is often dependent on the loading history. Repeatedly cycling a specimen with increasing displacement amplitudes tends to produce different response than simply applying a monotonically increasing displacement. This is quite intuitive to most engineers. However, laboratory tests are often carried out with “canned” (termed here as “standard”) fully-reversed cyclic loading protocols that do not reflect actual earthquake loadings. Why? Because of historical precedence of using certain standard protocols, and general recognition that standard protocols are considered worst case loadings. With the emergence of performance-based engineering, it is essential to use realistic estimates of component performance. We summarize standard protocols commonly used in practice and point out problems of using them as the main (and sometimes only) source of seismic performance determination. We then compare the incremental dynamic analysis (IDA) results of building models using component backbone curves based on “standard” lab tests to a model using more realistic backbone curves. It is found that the second model is much more rugged and has better agreement with the expected performance of new building designs. Given the challenge of accurately and economically simulating the degradation behavior of structural components, it is encouraged that researchers need to include testing with more realistic loading protocols so that the results are best suited for performance-based engineering.
Proceedings Title: 12th Canadian Conference on Earthquake Engineering
Conference Dates: June 17-20, 2019
Conference Location: Quebec City, -1
Pub Type: Conferences

Keywords

loading protocols, experimental testing, cyclic performance, performance-based seismic engineering
Created June 17, 2019, Updated August 20, 2019