Seismic analysis of complex structures: Practical application issues and case study

All large structures are vulnerable to earthquake damage. Local failures or total collapses of such structures represent not only immediate concern for loss of life and repair costs, but also major economic impacts due to loss of service. The 1989 Loma Prieta and 1994 Northridge earthquakes in California provided dramatic examples of the vulnerability of engineered structures and the extensive impact of their failure in regions classified as high seismic risk zones. Today, engineers throughout the world are faced with increasing requirements to assess the seismic vulnerability of existing structures, even in regions of relatively low seismic risk classification, and to design new, more sophisticated structures. The purpose of this paper is to discuss the particular features and benefits of ADINA with respect to the requirements of advanced seismic analysis. Major aspects of earthquake related analysis are discussed, i.e. static lateral push-over analysis, ground motion specification for dynamic analysis, and significant structural behavior phenomena associated with contact and ductile energy dissipation. The modelling of typical structural components is presented and analysis strategies are delineated via case study of a large public building. In addition to issues related to the as-built structure analysis, the philosophy of accommodating displacements via the deformation of highly ductile components or dampers introduced at existing expansion joint hinges and other appropriate structural locations is presented along with the requisite modelling requirements. With respect to post-processing, typical structural component performance is illustrated via monotonic and hysteretic energy characterizations as well as with standard displacement and force demand data. A summary of the analytical issues and their simulation within ADINA especially with respect to new capabilities, is also provided.