Abstract:

This dissertation focuses on analytical studies on the performance of primary and secondary systems in buildings with seismic protective devices. Emphasis was given in buildings equipped with viscous (linear and nonlinear) and metallic-yielding energy dissipation systems, and buildings seismically isolated with lead-rubber and friction-pendulum isolation systems. This study concentrates on three tasks: (1)?assessment of the validity and accuracy of the simplified analysis methods for buildings with damping systems for near-field and soft-soil ground motions; (2)?assessment of the performance of nonstructural and structural components in structures with damping systems; and (3)?assessment of the performance of nonstructural and structural components in seismically isolated structures.

The first task assesses of the accuracy of simplified methods for the analysis of buildings with energy dissipation devices for near-field and soft-soil ground motions. Nonlinear response-history and simplified methods of the 2003 NEHRP Recommended Provisions are used to analyze single-degree-of-freedom systems with linear viscous, nonlinear viscous, and yielding damping devices, as well as three-story moment frames with linear viscous and nonlinear viscous damping systems, to acquire knowledge on the influence of near-field and soft-soil ground motions on the accuracy of simplified methods of analysis.

The second task of this dissertation concentrates on an analytical study aimed at investigating the use of damping systems as a means of passive protection for secondary systems. Moment-frame buildings with and without damping systems on stiff- and soft-soil sites as well as on sites with near-field characteristics are designed by the procedures described in the 2003 NEHRP Recommended Provisions.

In the last task, an analytical study is carried out on the response of structural and nonstructural components in seismically isolated systems with a range of attributes, namely: (i)?structural systems with different stiffness (period) characteristics; (ii)?different types of seismic isolation hardware, including lead-rubber and friction-pendulum systems, with a range of isolation periods; (iii)?a series of parameters for upper/lower bound analysis for each particular isolation system; and (iv)?different types of seismic excitations, including far-field and near-field motions, all represented by suites of motions having a representative average spectrum. (Abstract shortened by UMI.)