Keywords: seismic assessment, school building, modelling, database, structural component, nonlinear analysis, automation.

Current nonlinear structural analysis technology has reached the point where the nonlinear response of a structure or a structural component can be very accurately simulated. Therefore, nonlinear analysis has become the most reliable method to assess the seismic performance of a structure. The Federal Emergency Management Agency (FEMA) [1] of the United States has published standards which suggest using nonlinear static procedure-pushover analysis to obtain the nonlinear behavior and damage sequence of a structure under severe earthquake load, and using the analysis result to evaluate the performance and reliability of that structure. In addition, pushover analysis is already supported by and has been made simple by some commercial software, such as ETABS.

The reliability of a nonlinear analysis result depends much on the validity of the analytical model. A valid analytical model must be able to numerically describe the realistic post-damage behavior of the structure. Otherwise, the result will be unreliable and useless. The building of a nonlinear model of a structure must rely on an experienced professional opinion based on the design data and current condition of the structure. In comparison with the following analysis calculation by computer, the modeling is usually much more time-consuming and demanding of experience. Recently, the National Center for Research on Earthquake Engineering Research (NCREE) in Taiwan has established a database for school buildings. The database contains surveying data of over 12,000 school buildings in Taiwan. The collected data includes dimensions, geometry, building date, floor area, number of columns, number of walls, etc. of school buildings. The reason for establishing this database is for evaluating the seismic performance of those school buildings surveyed. The seismic resistance ability of school buildings is very important because it is a high human density facility. In addition, it should serve as a shelter for casualties after a severe earthquake.

Since most school buildings were built based on a few standard plans, it is possible to automatically create a linear-elastic model for school buildings by a standard procedure using some school building data, which has been collected in the school building database. To build a nonlinear model, however, requires nonlinear elements or nonlinear models for simulating the nonlinear behavior of various structural components. Knowledge of structural component modeling cannot be automatically generated by a computer program.

In order to enable the automatic modeling of school buildings for nonlinear analysis, this study has established a structural component model database by collecting various structural component models from various sources. A typical structural component model is composed of simple nonlinear elements and bounds on the element's validity. Usually, each nonlinear element of a model describes a different deformation mechanism that affects the nonlinear behavior of a structural component. The behavior of a nonlinear element is described by one or a few performance curves, which may be established by codifying experimental results or theorems. By considering the characteristics of and relationships between the above modeling entities, this paper proposes a data structure and a database schema for storing structural component models.

The proposed structural component model database alone can serve as a decision supporting system for building nonlinear analytical models. Furthermore, since all the modeling information is available either in the school building database or the structural component model database, a standard procedure to automatically generate school building models by querying the two databases based on the user's selections is proposed. An automatic modeling system is designed and implemented based on the above procedure. By using this system, analytical models of school buildings can be built efficiently for seismic assessment. The concept of this study is illustrated in Figure 1.

1

Federal Emergency Management Agency (FEMA)-273, "NEHRP guidelines for the seismic rehabilitation of buildings", FEMA 273/October 1997, Applied Technology Council, Redwood City, California, USA, 1997.

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