The Thiel–Zsutty earthquake damage model, reformulated and extended

Abstract

SummaryThe Thiel–Zsutty (TZ) model predicts mean and the probability distribution function for earthquake damageability of building as a function of peak ground acceleration. ATC‐13‐1 provides an alternate damageability model based on modified Mercalli intensity characterization of ground motion and a beta distribution function for selected building types. This paper provides a reconciliation of the TZ and Applied Technology Council (ATC) methods. It is shown that the beta distribution can provide a continuous representation of the step‐wise TZ Markov distribution function. When the TZ model uses a compression factor for the standard deviation to represent the degree of uncertainty in the parameters, then the TZ results are found to be consistent with the ATC‐13‐1 distribution function for a specific compression factor of 0.40. This paper provides a new, simply applicable method to determine the damage distribution function for a given site, building type, and site conditions; using a beta distribution and allowing inclusion of the degree of confidence the assessor has in the determination of the parameters. New equations are provided to estimate the mean, standard deviation, and upper confidence limit of the damage ratio.

The revised Thiel–Zsutty earthquake damage model—Reformulated and extended—Part 2

“…One of the most common uses of the TZ model is evaluation of the damage risk posed by existing, new, or modified buildings for financial transactions, either for lending or equity investment. In a series of papers in this Journal, methods are discussed to apply the TZ model in a wide range of applications for individual and groups of buildings. Implementation of the reformulated TZR model to determine damageability values for a building includes the following sequential steps: Choose ASTM Level of Investigation. Perform an assessment of the building and site to determine the seismic performance characteristics consistent with the requirements of ASTM for the Level of investigation specified. Select a reference b value corresponding to the type of building and modify it to reflect the specific knowledge and understanding of the building's expected seismic performance.…”

“…Application of the TZR model requires assessments of three major contributors to the seismic damageability of a particular building: the intensity of ground motion as represented by site acceleration PGA, ( a ); the site‐specific soil characteristics, (s); building damageability and response parameters ( b and m ); and the assessment uncertainty factor ( α ) that reflects the degree of knowledge in the determination of seismic performance. This paper address how to assign damage parameters in the TZR model extending the discussions in the original 1987 paper and subsequent papers on application of TZ, including the uncertainty factor ( α ) . Additional information is provided below on how to assign model parameters, including assignments corresponding to the ASCE 7 provisions and system descriptions, and to tall buildings requiring special analyses.…”

“…In the Part 1 of The Thiel–Zsutty Earthquake Damage Model, Reformulated and Extended , the original Thiel–Zsutty (TZ) damage estimation model employed a discrete Markov probability distribution for building damageability states was changed to the revised Thiel–Zsutty (TZR) model, which employs the continuous beta distribution for damageability . Further, the revised model employs an α factor to represent the level of knowledge concerning building damageability characteristics and site conditions.…”

Evaluating the safe interim use of seismically deficient buildings

“…The TZR method is relatively easy to apply and is based upon field data of the damage performance of over 30,000 buildings in actual earthquakes in California, the United States, and China along with expert opinion, and results of its applications are peer reviewable. The method provides base damageability parameters for many structural systems and soil conditions, along with suggested ways to quantify the uncertainty involved in the evaluation of these parameters for application to a given building and site …”

“…The seismic load density function can be obtained from a site‐specific seismic hazard report. For the building response density function, the data‐based Thiel–Zsutty reformulated (TZR) damage model will be used in this paper . Later sections of this paper will develop the seismic load density function in terms of the earthquake hazard at a building site and the damageability density function of the building response.…”